import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

toolkit/components/osfile/modules/moz.build

@@ -0,0 +1,22 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+EXTRA_JS_MODULES.osfile += [
+    'osfile_async_front.jsm',
+    'osfile_async_worker.js',
+    'osfile_native.jsm',
+    'osfile_shared_allthreads.jsm',
+    'osfile_shared_front.jsm',
+    'osfile_unix_allthreads.jsm',
+    'osfile_unix_back.jsm',
+    'osfile_unix_front.jsm',
+    'osfile_win_allthreads.jsm',
+    'osfile_win_back.jsm',
+    'osfile_win_front.jsm',
+    'ospath.jsm',
+    'ospath_unix.jsm',
+    'ospath_win.jsm',
+]

toolkit/components/osfile/modules/osfile_async_worker.js

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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+
+if (this.Components) {
+  throw new Error("This worker can only be loaded from a worker thread");
+}
+
+// Worker thread for osfile asynchronous front-end
+
+(function(exports) {
+  "use strict";
+
+  // Timestamps, for use in Telemetry.
+  // The object is set to |null| once it has been sent
+  // to the main thread.
+  let timeStamps = {
+    entered: Date.now(),
+    loaded: null
+  };
+
+  importScripts("resource://gre/modules/osfile.jsm");
+
+  let PromiseWorker = require("resource://gre/modules/workers/PromiseWorker.js");
+  let SharedAll = require("resource://gre/modules/osfile/osfile_shared_allthreads.jsm");
+  let LOG = SharedAll.LOG.bind(SharedAll, "Agent");
+
+  let worker = new PromiseWorker.AbstractWorker();
+  worker.dispatch = function(method, args = []) {
+    return Agent[method](...args);
+  },
+  worker.log = LOG;
+  worker.postMessage = function(message, ...transfers) {
+    if (timeStamps) {
+      message.timeStamps = timeStamps;
+      timeStamps = null;
+    }
+    self.postMessage(message, ...transfers);
+  };
+  worker.close = function() {
+    self.close();
+  };
+  let Meta = PromiseWorker.Meta;
+
+  self.addEventListener("message", msg => worker.handleMessage(msg));
+
+ /**
+  * A data structure used to track opened resources
+  */
+  let ResourceTracker = function ResourceTracker() {
+   // A number used to generate ids
+   this._idgen = 0;
+   // A map from id to resource
+   this._map = new Map();
+  };
+  ResourceTracker.prototype = {
+   /**
+    * Get a resource from its unique identifier.
+    */
+   get: function(id) {
+     let result = this._map.get(id);
+     if (result == null) {
+       return result;
+     }
+     return result.resource;
+   },
+   /**
+    * Remove a resource from its unique identifier.
+    */
+   remove: function(id) {
+     if (!this._map.has(id)) {
+       throw new Error("Cannot find resource id " + id);
+     }
+     this._map.delete(id);
+   },
+   /**
+    * Add a resource, return a new unique identifier
+    *
+    * @param {*} resource A resource.
+    * @param {*=} info Optional information. For debugging purposes.
+    *
+    * @return {*} A unique identifier. For the moment, this is a number,
+    * but this might not remain the case forever.
+    */
+   add: function(resource, info) {
+     let id = this._idgen++;
+     this._map.set(id, {resource:resource, info:info});
+     return id;
+   },
+   /**
+    * Return a list of all open resources i.e. the ones still present in
+    * ResourceTracker's _map.
+    */
+   listOpenedResources: function listOpenedResources() {
+     return Array.from(this._map, ([id, resource]) => resource.info.path);
+   }
+  };
+
+ /**
+  * A map of unique identifiers to opened files.
+  */
+  let OpenedFiles = new ResourceTracker();
+
+ /**
+  * Execute a function in the context of a given file.
+  *
+  * @param {*} id A unique identifier, as used by |OpenFiles|.
+  * @param {Function} f A function to call.
+  * @param {boolean} ignoreAbsent If |true|, the error is ignored. Otherwise, the error causes an exception.
+  * @return The return value of |f()|
+  *
+  * This function attempts to get the file matching |id|. If
+  * the file exists, it executes |f| within the |this| set
+  * to the corresponding file. Otherwise, it throws an error.
+  */
+  let withFile = function withFile(id, f, ignoreAbsent) {
+   let file = OpenedFiles.get(id);
+   if (file == null) {
+     if (!ignoreAbsent) {
+       throw OS.File.Error.closed("accessing file");
+     }
+     return undefined;
+   }
+   return f.call(file);
+  };
+
+  let OpenedDirectoryIterators = new ResourceTracker();
+  let withDir = function withDir(fd, f, ignoreAbsent) {
+   let file = OpenedDirectoryIterators.get(fd);
+   if (file == null) {
+     if (!ignoreAbsent) {
+       throw OS.File.Error.closed("accessing directory");
+     }
+     return undefined;
+   }
+   if (!(file instanceof File.DirectoryIterator)) {
+     throw new Error("file is not a directory iterator " + file.__proto__.toSource());
+   }
+   return f.call(file);
+  };
+
+  let Type = exports.OS.Shared.Type;
+
+  let File = exports.OS.File;
+
+ /**
+  * The agent.
+  *
+  * It is in charge of performing method-specific deserialization
+  * of messages, calling the function/method of OS.File and serializing
+  * back the results.
+  */
+  let Agent = {
+   // Update worker's OS.Shared.DEBUG flag message from controller.
+   SET_DEBUG: function(aDEBUG) {
+     SharedAll.Config.DEBUG = aDEBUG;
+   },
+   // Return worker's current OS.Shared.DEBUG value to controller.
+   // Note: This is used for testing purposes.
+   GET_DEBUG: function() {
+     return SharedAll.Config.DEBUG;
+   },
+   /**
+    * Execute shutdown sequence, returning data on leaked file descriptors.
+    *
+    * @param {bool} If |true|, kill the worker if this would not cause
+    * leaks.
+    */
+   Meta_shutdown: function(kill) {
+     let result = {
+       openedFiles: OpenedFiles.listOpenedResources(),
+       openedDirectoryIterators: OpenedDirectoryIterators.listOpenedResources(),
+       killed: false // Placeholder
+     };
+
+     // Is it safe to kill the worker?
+     let safe = result.openedFiles.length == 0
+           && result.openedDirectoryIterators.length == 0;
+     result.killed = safe && kill;
+
+     return new Meta(result, {shutdown: result.killed});
+   },
+   // Functions of OS.File
+   stat: function stat(path, options) {
+     return exports.OS.File.Info.toMsg(
+       exports.OS.File.stat(Type.path.fromMsg(path), options));
+   },
+   setPermissions: function setPermissions(path, options = {}) {
+     return exports.OS.File.setPermissions(Type.path.fromMsg(path), options);
+   },
+   setDates: function setDates(path, accessDate, modificationDate) {
+     return exports.OS.File.setDates(Type.path.fromMsg(path), accessDate,
+                                     modificationDate);
+   },
+   getCurrentDirectory: function getCurrentDirectory() {
+     return exports.OS.Shared.Type.path.toMsg(File.getCurrentDirectory());
+   },
+   setCurrentDirectory: function setCurrentDirectory(path) {
+     File.setCurrentDirectory(exports.OS.Shared.Type.path.fromMsg(path));
+   },
+   copy: function copy(sourcePath, destPath, options) {
+     return File.copy(Type.path.fromMsg(sourcePath),
+       Type.path.fromMsg(destPath), options);
+   },
+   move: function move(sourcePath, destPath, options) {
+     return File.move(Type.path.fromMsg(sourcePath),
+       Type.path.fromMsg(destPath), options);
+   },
+   getAvailableFreeSpace: function getAvailableFreeSpace(sourcePath) {
+     return Type.uint64_t.toMsg(
+       File.getAvailableFreeSpace(Type.path.fromMsg(sourcePath)));
+   },
+   makeDir: function makeDir(path, options) {
+     return File.makeDir(Type.path.fromMsg(path), options);
+   },
+   removeEmptyDir: function removeEmptyDir(path, options) {
+     return File.removeEmptyDir(Type.path.fromMsg(path), options);
+   },
+   remove: function remove(path, options) {
+     return File.remove(Type.path.fromMsg(path), options);
+   },
+   open: function open(path, mode, options) {
+     let filePath = Type.path.fromMsg(path);
+     let file = File.open(filePath, mode, options);
+     return OpenedFiles.add(file, {
+       // Adding path information to keep track of opened files
+       // to report leaks when debugging.
+       path: filePath
+     });
+   },
+   openUnique: function openUnique(path, options) {
+     let filePath = Type.path.fromMsg(path);
+     let openedFile = OS.Shared.AbstractFile.openUnique(filePath, options);
+     let resourceId = OpenedFiles.add(openedFile.file, {
+       // Adding path information to keep track of opened files
+       // to report leaks when debugging.
+       path: openedFile.path
+     });
+
+     return {
+       path: openedFile.path,
+       file: resourceId
+     };
+   },
+   read: function read(path, bytes, options) {
+     let data = File.read(Type.path.fromMsg(path), bytes, options);
+     if (typeof data == "string") {
+       return data;
+     }
+     return new Meta({
+         buffer: data.buffer,
+         byteOffset: data.byteOffset,
+         byteLength: data.byteLength
+     }, {
+       transfers: [data.buffer]
+     });
+   },
+   exists: function exists(path) {
+     return File.exists(Type.path.fromMsg(path));
+   },
+   writeAtomic: function writeAtomic(path, buffer, options) {
+     if (options.tmpPath) {
+       options.tmpPath = Type.path.fromMsg(options.tmpPath);
+     }
+     return File.writeAtomic(Type.path.fromMsg(path),
+                             Type.voidptr_t.fromMsg(buffer),
+                             options
+                            );
+   },
+   removeDir: function(path, options) {
+     return File.removeDir(Type.path.fromMsg(path), options);
+   },
+   new_DirectoryIterator: function new_DirectoryIterator(path, options) {
+     let directoryPath = Type.path.fromMsg(path);
+     let iterator = new File.DirectoryIterator(directoryPath, options);
+     return OpenedDirectoryIterators.add(iterator, {
+       // Adding path information to keep track of opened directory
+       // iterators to report leaks when debugging.
+       path: directoryPath
+     });
+   },
+   // Methods of OS.File
+   File_prototype_close: function close(fd) {
+     return withFile(fd,
+       function do_close() {
+         try {
+           return this.close();
+         } finally {
+           OpenedFiles.remove(fd);
+         }
+     });
+   },
+   File_prototype_stat: function stat(fd) {
+     return withFile(fd,
+       function do_stat() {
+         return exports.OS.File.Info.toMsg(this.stat());
+       });
+   },
+   File_prototype_setPermissions: function setPermissions(fd, options = {}) {
+     return withFile(fd,
+       function do_setPermissions() {
+         return this.setPermissions(options);
+       });
+   },
+   File_prototype_setDates: function setDates(fd, accessTime, modificationTime) {
+     return withFile(fd,
+       function do_setDates() {
+         return this.setDates(accessTime, modificationTime);
+       });
+   },
+   File_prototype_read: function read(fd, nbytes, options) {
+     return withFile(fd,
+       function do_read() {
+         let data = this.read(nbytes, options);
+         return new Meta({
+             buffer: data.buffer,
+             byteOffset: data.byteOffset,
+             byteLength: data.byteLength
+         }, {
+           transfers: [data.buffer]
+         });
+       }
+     );
+   },
+   File_prototype_readTo: function readTo(fd, buffer, options) {
+     return withFile(fd,
+       function do_readTo() {
+         return this.readTo(exports.OS.Shared.Type.voidptr_t.fromMsg(buffer),
+         options);
+       });
+   },
+   File_prototype_write: function write(fd, buffer, options) {
+     return withFile(fd,
+       function do_write() {
+         return this.write(exports.OS.Shared.Type.voidptr_t.fromMsg(buffer),
+         options);
+       });
+   },
+   File_prototype_setPosition: function setPosition(fd, pos, whence) {
+     return withFile(fd,
+       function do_setPosition() {
+         return this.setPosition(pos, whence);
+       });
+   },
+   File_prototype_getPosition: function getPosition(fd) {
+     return withFile(fd,
+       function do_getPosition() {
+         return this.getPosition();
+       });
+   },
+   File_prototype_flush: function flush(fd) {
+     return withFile(fd,
+       function do_flush() {
+         return this.flush();
+       });
+   },
+   // Methods of OS.File.DirectoryIterator
+   DirectoryIterator_prototype_next: function next(dir) {
+     return withDir(dir,
+       function do_next() {
+         try {
+           return File.DirectoryIterator.Entry.toMsg(this.next());
+         } catch (x) {
+           if (x == StopIteration) {
+             OpenedDirectoryIterators.remove(dir);
+           }
+           throw x;
+         }
+       }, false);
+   },
+   DirectoryIterator_prototype_nextBatch: function nextBatch(dir, size) {
+     return withDir(dir,
+       function do_nextBatch() {
+         let result;
+         try {
+           result = this.nextBatch(size);
+         } catch (x) {
+           OpenedDirectoryIterators.remove(dir);
+           throw x;
+         }
+         return result.map(File.DirectoryIterator.Entry.toMsg);
+       }, false);
+   },
+   DirectoryIterator_prototype_close: function close(dir) {
+     return withDir(dir,
+       function do_close() {
+         this.close();
+         OpenedDirectoryIterators.remove(dir);
+       }, true);// ignore error to support double-closing |DirectoryIterator|
+   },
+   DirectoryIterator_prototype_exists: function exists(dir) {
+     return withDir(dir,
+       function do_exists() {
+         return this.exists();
+       });
+   }
+  };
+  if (!SharedAll.Constants.Win) {
+    Agent.unixSymLink = function unixSymLink(sourcePath, destPath) {
+      return File.unixSymLink(Type.path.fromMsg(sourcePath),
+        Type.path.fromMsg(destPath));
+    };
+  }
+
+  timeStamps.loaded = Date.now();
+})(this);

toolkit/components/osfile/modules/osfile_native.jsm

@@ -0,0 +1,70 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Native (xpcom) implementation of key OS.File functions
+ */
+
+"use strict";
+
+this.EXPORTED_SYMBOLS = ["read"];
+
+var {results: Cr, utils: Cu, interfaces: Ci} = Components;
+
+var SharedAll = Cu.import("resource://gre/modules/osfile/osfile_shared_allthreads.jsm", {});
+
+var SysAll = {};
+if (SharedAll.Constants.Win) {
+  Cu.import("resource://gre/modules/osfile/osfile_win_allthreads.jsm", SysAll);
+} else if (SharedAll.Constants.libc) {
+  Cu.import("resource://gre/modules/osfile/osfile_unix_allthreads.jsm", SysAll);
+} else {
+  throw new Error("I am neither under Windows nor under a Posix system");
+}
+var {Promise} = Cu.import("resource://gre/modules/Promise.jsm", {});
+var {XPCOMUtils} = Cu.import("resource://gre/modules/XPCOMUtils.jsm", {});
+
+/**
+ * The native service holding the implementation of the functions.
+ */
+XPCOMUtils.defineLazyServiceGetter(this,
+  "Internals",
+  "@mozilla.org/toolkit/osfile/native-internals;1",
+  "nsINativeOSFileInternalsService");
+
+/**
+ * Native implementation of OS.File.read
+ *
+ * This implementation does not handle option |compression|.
+ */
+this.read = function(path, options = {}) {
+  // Sanity check on types of options
+  if ("encoding" in options && typeof options.encoding != "string") {
+    return Promise.reject(new TypeError("Invalid type for option encoding"));
+  }
+  if ("compression" in options && typeof options.compression != "string") {
+    return Promise.reject(new TypeError("Invalid type for option compression"));
+  }
+  if ("bytes" in options && typeof options.bytes != "number") {
+    return Promise.reject(new TypeError("Invalid type for option bytes"));
+  }
+
+  let deferred = Promise.defer();
+  Internals.read(path,
+    options,
+    function onSuccess(success) {
+      success.QueryInterface(Ci.nsINativeOSFileResult);
+      if ("outExecutionDuration" in options) {
+        options.outExecutionDuration =
+          success.executionDurationMS +
+          (options.outExecutionDuration || 0);
+      }
+      deferred.resolve(success.result);
+    },
+    function onError(operation, oserror) {
+      deferred.reject(new SysAll.Error(operation, oserror, path));
+    }
+  );
+  return deferred.promise;
+};

toolkit/components/osfile/modules/osfile_shared_front.jsm

@@ -0,0 +1,567 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Code shared by OS.File front-ends.
+ *
+ * This code is meant to be included by another library. It is also meant to
+ * be executed only on a worker thread.
+ */
+
+if (typeof Components != "undefined") {
+  throw new Error("osfile_shared_front.jsm cannot be used from the main thread");
+}
+(function(exports) {
+
+var SharedAll =
+  require("resource://gre/modules/osfile/osfile_shared_allthreads.jsm");
+var Path = require("resource://gre/modules/osfile/ospath.jsm");
+var Lz4 =
+  require("resource://gre/modules/lz4.js");
+var LOG = SharedAll.LOG.bind(SharedAll, "Shared front-end");
+var clone = SharedAll.clone;
+
+/**
+ * Code shared by implementations of File.
+ *
+ * @param {*} fd An OS-specific file handle.
+ * @param {string} path File path of the file handle, used for error-reporting.
+ * @constructor
+ */
+var AbstractFile = function AbstractFile(fd, path) {
+  this._fd = fd;
+  if (!path) {
+    throw new TypeError("path is expected");
+  }
+  this._path = path;
+};
+
+AbstractFile.prototype = {
+  /**
+   * Return the file handle.
+   *
+   * @throw OS.File.Error if the file has been closed.
+   */
+  get fd() {
+    if (this._fd) {
+      return this._fd;
+    }
+    throw OS.File.Error.closed("accessing file", this._path);
+  },
+  /**
+   * Read bytes from this file to a new buffer.
+   *
+   * @param {number=} maybeBytes (deprecated, please use options.bytes)
+   * @param {JSON} options
+   * @return {Uint8Array} An array containing the bytes read.
+   */
+  read: function read(maybeBytes, options = {}) {
+    if (typeof maybeBytes === "object") {
+    // Caller has skipped `maybeBytes` and provided an options object.
+      options = clone(maybeBytes);
+      maybeBytes = null;
+    } else {
+      options = options || {};
+    }
+    let bytes = options.bytes || undefined;
+    if (bytes === undefined) {
+      bytes = maybeBytes == null ? this.stat().size : maybeBytes;
+    }
+    let buffer = new Uint8Array(bytes);
+    let pos = 0;
+    while (pos < bytes) {
+      let length = bytes - pos;
+      let view = new DataView(buffer.buffer, pos, length);
+      let chunkSize = this._read(view, length, options);
+      if (chunkSize == 0) {
+        break;
+      }
+      pos += chunkSize;
+    }
+    if (pos == bytes) {
+      return buffer;
+    } else {
+      return buffer.subarray(0, pos);
+    }
+  },
+
+  /**
+   * Write bytes from a buffer to this file.
+   *
+   * Note that, by default, this function may perform several I/O
+   * operations to ensure that the buffer is fully written.
+   *
+   * @param {Typed array} buffer The buffer in which the the bytes are
+   * stored. The buffer must be large enough to accomodate |bytes| bytes.
+   * @param {*=} options Optionally, an object that may contain the
+   * following fields:
+   * - {number} bytes The number of |bytes| to write from the buffer. If
+   * unspecified, this is |buffer.byteLength|.
+   *
+   * @return {number} The number of bytes actually written.
+   */
+  write: function write(buffer, options = {}) {
+    let bytes =
+      SharedAll.normalizeBufferArgs(buffer, ("bytes" in options) ? options.bytes : undefined);
+    let pos = 0;
+    while (pos < bytes) {
+      let length = bytes - pos;
+      let view = new DataView(buffer.buffer, buffer.byteOffset + pos, length);
+      let chunkSize = this._write(view, length, options);
+      pos += chunkSize;
+    }
+    return pos;
+  }
+};
+
+/**
+ * Creates and opens a file with a unique name. By default, generate a random HEX number and use it to create a unique new file name.
+ *
+ * @param {string} path The path to the file.
+ * @param {*=} options Additional options for file opening. This
+ * implementation interprets the following fields:
+ *
+ * - {number} humanReadable If |true|, create a new filename appending a decimal number. ie: filename-1.ext, filename-2.ext.
+ *  If |false| use HEX numbers ie: filename-A65BC0.ext
+ * - {number} maxReadableNumber Used to limit the amount of tries after a failed
+ *  file creation. Default is 20.
+ *
+ * @return {Object} contains A file object{file} and the path{path}.
+ * @throws {OS.File.Error} If the file could not be opened.
+ */
+AbstractFile.openUnique = function openUnique(path, options = {}) {
+  let mode = {
+    create : true
+  };
+
+  let dirName = Path.dirname(path);
+  let leafName = Path.basename(path);
+  let lastDotCharacter = leafName.lastIndexOf('.');
+  let fileName = leafName.substring(0, lastDotCharacter != -1 ? lastDotCharacter : leafName.length);
+  let suffix = (lastDotCharacter != -1 ? leafName.substring(lastDotCharacter) : "");
+  let uniquePath = "";
+  let maxAttempts = options.maxAttempts || 99;
+  let humanReadable = !!options.humanReadable;
+  const HEX_RADIX = 16;
+  // We produce HEX numbers between 0 and 2^24 - 1.
+  const MAX_HEX_NUMBER = 16777215;
+
+  try {
+    return {
+      path: path,
+      file: OS.File.open(path, mode)
+    };
+  } catch (ex if ex instanceof OS.File.Error && ex.becauseExists) {
+    for (let i = 0; i < maxAttempts; ++i) {
+      try {
+        if (humanReadable) {
+          uniquePath = Path.join(dirName, fileName + "-" + (i + 1) + suffix);
+        } else {
+          let hexNumber = Math.floor(Math.random() * MAX_HEX_NUMBER).toString(HEX_RADIX);
+          uniquePath = Path.join(dirName, fileName + "-" + hexNumber + suffix);
+        }
+        return {
+          path: uniquePath,
+          file: OS.File.open(uniquePath, mode)
+        };
+      } catch (ex if ex instanceof OS.File.Error && ex.becauseExists) {
+        // keep trying ...
+      }
+    }
+    throw OS.File.Error.exists("could not find an unused file name.", path);
+  }
+};
+
+/**
+ * Code shared by iterators.
+ */
+AbstractFile.AbstractIterator = function AbstractIterator() {
+};
+AbstractFile.AbstractIterator.prototype = {
+  /**
+   * Allow iterating with |for|
+   */
+  __iterator__: function __iterator__() {
+    return this;
+  },
+  /**
+   * Apply a function to all elements of the directory sequentially.
+   *
+   * @param {Function} cb This function will be applied to all entries
+   * of the directory. It receives as arguments
+   *  - the OS.File.Entry corresponding to the entry;
+   *  - the index of the entry in the enumeration;
+   *  - the iterator itself - calling |close| on the iterator stops
+   *   the loop.
+   */
+  forEach: function forEach(cb) {
+    let index = 0;
+    for (let entry in this) {
+      cb(entry, index++, this);
+    }
+  },
+  /**
+   * Return several entries at once.
+   *
+   * Entries are returned in the same order as a walk with |forEach| or
+   * |for(...)|.
+   *
+   * @param {number=} length If specified, the number of entries
+   * to return. If unspecified, return all remaining entries.
+   * @return {Array} An array containing the next |length| entries, or
+   * less if the iteration contains less than |length| entries left.
+   */
+  nextBatch: function nextBatch(length) {
+    let array = [];
+    let i = 0;
+    for (let entry in this) {
+      array.push(entry);
+      if (++i >= length) {
+        return array;
+      }
+    }
+    return array;
+  }
+};
+
+/**
+ * Utility function shared by implementations of |OS.File.open|:
+ * extract read/write/trunc/create/existing flags from a |mode|
+ * object.
+ *
+ * @param {*=} mode An object that may contain fields |read|,
+ * |write|, |truncate|, |create|, |existing|. These fields
+ * are interpreted only if true-ish.
+ * @return {{read:bool, write:bool, trunc:bool, create:bool,
+ * existing:bool}} an object recapitulating the options set
+ * by |mode|.
+ * @throws {TypeError} If |mode| contains other fields, or
+ * if it contains both |create| and |truncate|, or |create|
+ * and |existing|.
+ */
+AbstractFile.normalizeOpenMode = function normalizeOpenMode(mode) {
+  let result = {
+    read: false,
+    write: false,
+    trunc: false,
+    create: false,
+    existing: false,
+    append: true
+  };
+  for (let key in mode) {
+    let val = !!mode[key]; // bool cast.
+    switch (key) {
+    case "read":
+      result.read = val;
+      break;
+    case "write":
+      result.write = val;
+      break;
+    case "truncate": // fallthrough
+    case "trunc":
+      result.trunc = val;
+      result.write |= val;
+      break;
+    case "create":
+      result.create = val;
+      result.write |= val;
+      break;
+    case "existing": // fallthrough
+    case "exist":
+      result.existing = val;
+      break;
+    case "append":
+      result.append = val;
+      break;
+    default:
+      throw new TypeError("Mode " + key + " not understood");
+    }
+  }
+  // Reject opposite modes
+  if (result.existing && result.create) {
+    throw new TypeError("Cannot specify both existing:true and create:true");
+  }
+  if (result.trunc && result.create) {
+    throw new TypeError("Cannot specify both trunc:true and create:true");
+  }
+  // Handle read/write
+  if (!result.write) {
+    result.read = true;
+  }
+  return result;
+};
+
+/**
+ * Return the contents of a file.
+ *
+ * @param {string} path The path to the file.
+ * @param {number=} bytes Optionally, an upper bound to the number of bytes
+ * to read. DEPRECATED - please use options.bytes instead.
+ * @param {object=} options Optionally, an object with some of the following
+ * fields:
+ * - {number} bytes An upper bound to the number of bytes to read.
+ * - {string} compression If "lz4" and if the file is compressed using the lz4
+ *   compression algorithm, decompress the file contents on the fly.
+ *
+ * @return {Uint8Array} A buffer holding the bytes
+ * and the number of bytes read from the file.
+ */
+AbstractFile.read = function read(path, bytes, options = {}) {
+  if (bytes && typeof bytes == "object") {
+    options = bytes;
+    bytes = options.bytes || null;
+  }
+  if ("encoding" in options && typeof options.encoding != "string") {
+    throw new TypeError("Invalid type for option encoding");
+  }
+  if ("compression" in options && typeof options.compression != "string") {
+    throw new TypeError("Invalid type for option compression: " + options.compression);
+  }
+  if ("bytes" in options && typeof options.bytes != "number") {
+    throw new TypeError("Invalid type for option bytes");
+  }
+  let file = exports.OS.File.open(path);
+  try {
+    let buffer = file.read(bytes, options);
+    if ("compression" in options) {
+      if (options.compression == "lz4") {
+        options = Object.create(options);
+        options.path = path;
+        buffer = Lz4.decompressFileContent(buffer, options);
+      } else {
+        throw OS.File.Error.invalidArgument("Compression");
+      }
+    }
+    if (!("encoding" in options)) {
+      return buffer;
+    }
+    let decoder;
+    try {
+      decoder = new TextDecoder(options.encoding);
+    } catch (ex if ex instanceof RangeError) {
+      throw OS.File.Error.invalidArgument("Decode");
+    }
+    return decoder.decode(buffer);
+  } finally {
+    file.close();
+  }
+};
+
+/**
+ * Write a file, atomically.
+ *
+ * By opposition to a regular |write|, this operation ensures that,
+ * until the contents are fully written, the destination file is
+ * not modified.
+ *
+ * Limitation: In a few extreme cases (hardware failure during the
+ * write, user unplugging disk during the write, etc.), data may be
+ * corrupted. If your data is user-critical (e.g. preferences,
+ * application data, etc.), you may wish to consider adding options
+ * |tmpPath| and/or |flush| to reduce the likelihood of corruption, as
+ * detailed below. Note that no combination of options can be
+ * guaranteed to totally eliminate the risk of corruption.
+ *
+ * @param {string} path The path of the file to modify.
+ * @param {Typed Array | C pointer} buffer A buffer containing the bytes to write.
+ * @param {*=} options Optionally, an object determining the behavior
+ * of this function. This object may contain the following fields:
+ * - {number} bytes The number of bytes to write. If unspecified,
+ * |buffer.byteLength|. Required if |buffer| is a C pointer.
+ * - {string} tmpPath If |null| or unspecified, write all data directly
+ * to |path|. If specified, write all data to a temporary file called
+ * |tmpPath| and, once this write is complete, rename the file to
+ * replace |path|. Performing this additional operation is a little
+ * slower but also a little safer.
+ * - {bool} noOverwrite - If set, this function will fail if a file already
+ * exists at |path|.
+ * - {bool} flush - If |false| or unspecified, return immediately once the
+ * write is complete. If |true|, before writing, force the operating system
+ * to write its internal disk buffers to the disk. This is considerably slower
+ * (not just for the application but for the whole system) but also safer:
+ * if the system shuts down improperly (typically due to a kernel freeze
+ * or a power failure) or if the device is disconnected before the buffer
+ * is flushed, the file has more chances of not being corrupted.
+ * - {string} compression - If empty or unspecified, do not compress the file.
+ * If "lz4", compress the contents of the file atomically using lz4. For the
+ * time being, the container format is specific to Mozilla and cannot be read
+ * by means other than OS.File.read(..., { compression: "lz4"})
+ * - {string} backupTo - If specified, backup the destination file as |backupTo|.
+ * Note that this function renames the destination file before overwriting it.
+ * If the process or the operating system freezes or crashes
+ * during the short window between these operations,
+ * the destination file will have been moved to its backup.
+ *
+ * @return {number} The number of bytes actually written.
+ */
+AbstractFile.writeAtomic =
+     function writeAtomic(path, buffer, options = {}) {
+
+  // Verify that path is defined and of the correct type
+  if (typeof path != "string" || path == "") {
+    throw new TypeError("File path should be a (non-empty) string");
+  }
+  let noOverwrite = options.noOverwrite;
+  if (noOverwrite && OS.File.exists(path)) {
+    throw OS.File.Error.exists("writeAtomic", path);
+  }
+
+  if (typeof buffer == "string") {
+    // Normalize buffer to a C buffer by encoding it
+    let encoding = options.encoding || "utf-8";
+    buffer = new TextEncoder(encoding).encode(buffer);
+  }
+
+  if ("compression" in options && options.compression == "lz4") {
+    buffer = Lz4.compressFileContent(buffer, options);
+    options = Object.create(options);
+    options.bytes = buffer.byteLength;
+  }
+
+  let bytesWritten = 0;
+
+  if (!options.tmpPath) {
+    if (options.backupTo) {
+      try {
+        OS.File.move(path, options.backupTo, {noCopy: true});
+      } catch (ex if ex.becauseNoSuchFile) {
+        // The file doesn't exist, nothing to backup.
+      }
+    }
+    // Just write, without any renaming trick
+    let dest = OS.File.open(path, {write: true, truncate: true});
+    try {
+      bytesWritten = dest.write(buffer, options);
+      if (options.flush) {
+        dest.flush();
+      }
+    } finally {
+      dest.close();
+    }
+    return bytesWritten;
+  }
+
+  let tmpFile = OS.File.open(options.tmpPath, {write: true, truncate: true});
+  try {
+    bytesWritten = tmpFile.write(buffer, options);
+    if (options.flush) {
+      tmpFile.flush();
+    }
+  } catch (x) {
+    OS.File.remove(options.tmpPath);
+    throw x;
+  } finally {
+    tmpFile.close();
+  }
+
+  if (options.backupTo) {
+    try {
+      OS.File.move(path, options.backupTo, {noCopy: true});
+    } catch (ex if ex.becauseNoSuchFile) {
+      // The file doesn't exist, nothing to backup.
+    }
+  }
+
+  OS.File.move(options.tmpPath, path, {noCopy: true});
+  return bytesWritten;
+};
+
+/**
+ * This function is used by removeDir to avoid calling lstat for each
+ * files under the specified directory. External callers should not call
+ * this function directly.
+ */
+AbstractFile.removeRecursive = function(path, options = {}) {
+  let iterator = new OS.File.DirectoryIterator(path);
+  if (!iterator.exists()) {
+    if (!("ignoreAbsent" in options) || options.ignoreAbsent) {
+      return;
+    }
+  }
+
+  try {
+    for (let entry in iterator) {
+      if (entry.isDir) {
+        if (entry.isLink) {
+          // Unlike Unix symlinks, NTFS junctions or NTFS symlinks to
+          // directories are directories themselves. OS.File.remove()
+          // will not work for them.
+          OS.File.removeEmptyDir(entry.path, options);
+        } else {
+          // Normal directories.
+          AbstractFile.removeRecursive(entry.path, options);
+        }
+      } else {
+        // NTFS symlinks to files, Unix symlinks, or regular files.
+        OS.File.remove(entry.path, options);
+      }
+    }
+  } finally {
+    iterator.close();
+  }
+
+  OS.File.removeEmptyDir(path);
+};
+
+/**
+ * Create a directory and, optionally, its parent directories.
+ *
+ * @param {string} path The name of the directory.
+ * @param {*=} options Additional options.
+ *
+ * - {string} from If specified, the call to |makeDir| creates all the
+ * ancestors of |path| that are descendants of |from|. Note that |path|
+ * must be a descendant of |from|, and that |from| and its existing
+ * subdirectories present in |path|  must be user-writeable.
+ * Example:
+ *   makeDir(Path.join(profileDir, "foo", "bar"), { from: profileDir });
+ *  creates directories profileDir/foo, profileDir/foo/bar
+ * - {bool} ignoreExisting If |false|, throw an error if the directory
+ * already exists. |true| by default. Ignored if |from| is specified.
+ * - {number} unixMode Under Unix, if specified, a file creation mode,
+ * as per libc function |mkdir|. If unspecified, dirs are
+ * created with a default mode of 0700 (dir is private to
+ * the user, the user can read, write and execute). Ignored under Windows
+ * or if the file system does not support file creation modes.
+ * - {C pointer} winSecurity Under Windows, if specified, security
+ * attributes as per winapi function |CreateDirectory|. If
+ * unspecified, use the default security descriptor, inherited from
+ * the parent directory. Ignored under Unix or if the file system
+ * does not support security descriptors.
+ */
+AbstractFile.makeDir = function(path, options = {}) {
+  let from = options.from;
+  if (!from) {
+    OS.File._makeDir(path, options);
+    return;
+  }
+  if (!path.startsWith(from)) {
+    // Apparently, `from` is not a parent of `path`. However, we may
+    // have false negatives due to non-normalized paths, e.g.
+    // "foo//bar" is a parent of "foo/bar/sna".
+    path = Path.normalize(path);
+    from = Path.normalize(from);
+    if (!path.startsWith(from)) {
+      throw new Error("Incorrect use of option |from|: " + path + " is not a descendant of " + from);
+    }
+  }
+  let innerOptions = Object.create(options, {
+    ignoreExisting: {
+      value: true
+    }
+  });
+  // Compute the elements that appear in |path| but not in |from|.
+  let items = Path.split(path).components.slice(Path.split(from).components.length);
+  let current = from;
+  for (let item of items) {
+    current = Path.join(current, item);
+    OS.File._makeDir(current, innerOptions);
+  }
+};
+
+if (!exports.OS.Shared) {
+  exports.OS.Shared = {};
+}
+exports.OS.Shared.AbstractFile = AbstractFile;
+})(this);

toolkit/components/osfile/modules/osfile_unix_allthreads.jsm

@@ -0,0 +1,375 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This module defines the thread-agnostic components of the Unix version
+ * of OS.File. It depends on the thread-agnostic cross-platform components
+ * of OS.File.
+ *
+ * It serves the following purposes:
+ * - open libc;
+ * - define OS.Unix.Error;
+ * - define a few constants and types that need to be defined on all platforms.
+ *
+ * This module can be:
+ * - opened from the main thread as a jsm module;
+ * - opened from a chrome worker through require().
+ */
+
+"use strict";
+
+var SharedAll;
+if (typeof Components != "undefined") {
+  let Cu = Components.utils;
+  // Module is opened as a jsm module
+  Cu.import("resource://gre/modules/ctypes.jsm", this);
+
+  SharedAll = {};
+  Cu.import("resource://gre/modules/osfile/osfile_shared_allthreads.jsm", SharedAll);
+  this.exports = {};
+} else if (typeof module != "undefined" && typeof require != "undefined") {
+  // Module is loaded with require()
+  SharedAll = require("resource://gre/modules/osfile/osfile_shared_allthreads.jsm");
+} else {
+  throw new Error("Please open this module with Component.utils.import or with require()");
+}
+
+var LOG = SharedAll.LOG.bind(SharedAll, "Unix", "allthreads");
+var Const = SharedAll.Constants.libc;
+
+// Open libc
+var libc = new SharedAll.Library("libc",
+                                 "libc.so", "libSystem.B.dylib", "a.out");
+exports.libc = libc;
+
+// Define declareFFI
+var declareFFI = SharedAll.declareFFI.bind(null, libc);
+exports.declareFFI = declareFFI;
+
+// Define lazy binding
+var LazyBindings = {};
+libc.declareLazy(LazyBindings, "strerror",
+                 "strerror", ctypes.default_abi,
+                 /*return*/ ctypes.char.ptr,
+                 /*errnum*/ ctypes.int);
+
+/**
+ * A File-related error.
+ *
+ * To obtain a human-readable error message, use method |toString|.
+ * To determine the cause of the error, use the various |becauseX|
+ * getters. To determine the operation that failed, use field
+ * |operation|.
+ *
+ * Additionally, this implementation offers a field
+ * |unixErrno|, which holds the OS-specific error
+ * constant. If you need this level of detail, you may match the value
+ * of this field against the error constants of |OS.Constants.libc|.
+ *
+ * @param {string=} operation The operation that failed. If unspecified,
+ * the name of the calling function is taken to be the operation that
+ * failed.
+ * @param {number=} lastError The OS-specific constant detailing the
+ * reason of the error. If unspecified, this is fetched from the system
+ * status.
+ * @param {string=} path The file path that manipulated. If unspecified,
+ * assign the empty string.
+ *
+ * @constructor
+ * @extends {OS.Shared.Error}
+ */
+var OSError = function OSError(operation = "unknown operation",
+                               errno = ctypes.errno, path = "") {
+  SharedAll.OSError.call(this, operation, path);
+  this.unixErrno = errno;
+};
+OSError.prototype = Object.create(SharedAll.OSError.prototype);
+OSError.prototype.toString = function toString() {
+  return "Unix error " + this.unixErrno +
+    " during operation " + this.operation +
+    (this.path? " on file " + this.path : "") +
+    " (" + LazyBindings.strerror(this.unixErrno).readString() + ")";
+};
+OSError.prototype.toMsg = function toMsg() {
+  return OSError.toMsg(this);
+};
+
+/**
+ * |true| if the error was raised because a file or directory
+ * already exists, |false| otherwise.
+ */
+Object.defineProperty(OSError.prototype, "becauseExists", {
+  get: function becauseExists() {
+    return this.unixErrno == Const.EEXIST;
+  }
+});
+/**
+ * |true| if the error was raised because a file or directory
+ * does not exist, |false| otherwise.
+ */
+Object.defineProperty(OSError.prototype, "becauseNoSuchFile", {
+  get: function becauseNoSuchFile() {
+    return this.unixErrno == Const.ENOENT;
+  }
+});
+
+/**
+ * |true| if the error was raised because a directory is not empty
+ * does not exist, |false| otherwise.
+ */
+ Object.defineProperty(OSError.prototype, "becauseNotEmpty", {
+   get: function becauseNotEmpty() {
+     return this.unixErrno == Const.ENOTEMPTY;
+   }
+ });
+/**
+ * |true| if the error was raised because a file or directory
+ * is closed, |false| otherwise.
+ */
+Object.defineProperty(OSError.prototype, "becauseClosed", {
+  get: function becauseClosed() {
+    return this.unixErrno == Const.EBADF;
+  }
+});
+/**
+ * |true| if the error was raised because permission is denied to
+ * access a file or directory, |false| otherwise.
+ */
+Object.defineProperty(OSError.prototype, "becauseAccessDenied", {
+  get: function becauseAccessDenied() {
+    return this.unixErrno == Const.EACCES;
+  }
+});
+/**
+ * |true| if the error was raised because some invalid argument was passed,
+ * |false| otherwise.
+ */
+Object.defineProperty(OSError.prototype, "becauseInvalidArgument", {
+  get: function becauseInvalidArgument() {
+    return this.unixErrno == Const.EINVAL;
+  }
+});
+
+/**
+ * Serialize an instance of OSError to something that can be
+ * transmitted across threads (not necessarily a string).
+ */
+OSError.toMsg = function toMsg(error) {
+  return {
+    exn: "OS.File.Error",
+    fileName: error.moduleName,
+    lineNumber: error.lineNumber,
+    stack: error.moduleStack,
+    operation: error.operation,
+    unixErrno: error.unixErrno,
+    path: error.path
+  };
+};
+
+/**
+ * Deserialize a message back to an instance of OSError
+ */
+OSError.fromMsg = function fromMsg(msg) {
+  let error = new OSError(msg.operation, msg.unixErrno, msg.path);
+  error.stack = msg.stack;
+  error.fileName = msg.fileName;
+  error.lineNumber = msg.lineNumber;
+  return error;
+};
+exports.Error = OSError;
+
+/**
+ * Code shared by implementations of File.Info on Unix
+ *
+ * @constructor
+*/
+var AbstractInfo = function AbstractInfo(path, isDir, isSymLink, size, lastAccessDate,
+                                         lastModificationDate, unixLastStatusChangeDate,
+                                         unixOwner, unixGroup, unixMode) {
+  this._path = path;
+  this._isDir = isDir;
+  this._isSymlLink = isSymLink;
+  this._size = size;
+  this._lastAccessDate = lastAccessDate;
+  this._lastModificationDate = lastModificationDate;
+  this._unixLastStatusChangeDate = unixLastStatusChangeDate;
+  this._unixOwner = unixOwner;
+  this._unixGroup = unixGroup;
+  this._unixMode = unixMode;
+};
+
+AbstractInfo.prototype = {
+  /**
+   * The path of the file, used for error-reporting.
+   *
+   * @type {string}
+   */
+  get path() {
+    return this._path;
+  },
+  /**
+   * |true| if this file is a directory, |false| otherwise
+   */
+  get isDir() {
+    return this._isDir;
+  },
+  /**
+   * |true| if this file is a symbolink link, |false| otherwise
+   */
+  get isSymLink() {
+    return this._isSymlLink;
+  },
+  /**
+   * The size of the file, in bytes.
+   *
+   * Note that the result may be |NaN| if the size of the file cannot be
+   * represented in JavaScript.
+   *
+   * @type {number}
+   */
+  get size() {
+    return this._size;
+  },
+  /**
+   * The date of last access to this file.
+   *
+   * Note that the definition of last access may depend on the
+   * underlying operating system and file system.
+   *
+   * @type {Date}
+   */
+  get lastAccessDate() {
+    return this._lastAccessDate;
+  },
+  /**
+   * Return the date of last modification of this file.
+   */
+  get lastModificationDate() {
+    return this._lastModificationDate;
+  },
+  /**
+   * Return the date at which the status of this file was last modified
+   * (this is the date of the latest write/renaming/mode change/...
+   * of the file)
+   */
+  get unixLastStatusChangeDate() {
+    return this._unixLastStatusChangeDate;
+  },
+  /*
+   * Return the Unix owner of this file
+   */
+  get unixOwner() {
+    return this._unixOwner;
+  },
+  /*
+   * Return the Unix group of this file
+   */
+  get unixGroup() {
+    return this._unixGroup;
+  },
+  /*
+   * Return the Unix group of this file
+   */
+  get unixMode() {
+    return this._unixMode;
+  }
+};
+exports.AbstractInfo = AbstractInfo;
+
+/**
+ * Code shared by implementations of File.DirectoryIterator.Entry on Unix
+ *
+ * @constructor
+*/
+var AbstractEntry = function AbstractEntry(isDir, isSymLink, name, path) {
+  this._isDir = isDir;
+  this._isSymlLink = isSymLink;
+  this._name = name;
+  this._path = path;
+};
+
+AbstractEntry.prototype = {
+  /**
+   * |true| if the entry is a directory, |false| otherwise
+   */
+  get isDir() {
+    return this._isDir;
+  },
+  /**
+   * |true| if the entry is a directory, |false| otherwise
+   */
+  get isSymLink() {
+    return this._isSymlLink;
+  },
+  /**
+   * The name of the entry
+   * @type {string}
+   */
+  get name() {
+    return this._name;
+  },
+  /**
+   * The full path to the entry
+   */
+  get path() {
+    return this._path;
+  }
+};
+exports.AbstractEntry = AbstractEntry;
+
+// Special constants that need to be defined on all platforms
+
+exports.POS_START = Const.SEEK_SET;
+exports.POS_CURRENT = Const.SEEK_CUR;
+exports.POS_END = Const.SEEK_END;
+
+// Special types that need to be defined for communication
+// between threads
+var Type = Object.create(SharedAll.Type);
+exports.Type = Type;
+
+/**
+ * Native paths
+ *
+ * Under Unix, expressed as C strings
+ */
+Type.path = Type.cstring.withName("[in] path");
+Type.out_path = Type.out_cstring.withName("[out] path");
+
+// Special constructors that need to be defined on all threads
+OSError.closed = function closed(operation, path) {
+  return new OSError(operation, Const.EBADF, path);
+};
+
+OSError.exists = function exists(operation, path) {
+  return new OSError(operation, Const.EEXIST, path);
+};
+
+OSError.noSuchFile = function noSuchFile(operation, path) {
+  return new OSError(operation, Const.ENOENT, path);
+};
+
+OSError.invalidArgument = function invalidArgument(operation) {
+  return new OSError(operation, Const.EINVAL);
+};
+
+var EXPORTED_SYMBOLS = [
+  "declareFFI",
+  "libc",
+  "Error",
+  "AbstractInfo",
+  "AbstractEntry",
+  "Type",
+  "POS_START",
+  "POS_CURRENT",
+  "POS_END"
+];
+
+//////////// Boilerplate
+if (typeof Components != "undefined") {
+  this.EXPORTED_SYMBOLS = EXPORTED_SYMBOLS;
+  for (let symbol of EXPORTED_SYMBOLS) {
+    this[symbol] = exports[symbol];
+  }
+}

toolkit/components/osfile/modules/osfile_unix_back.jsm

@@ -0,0 +1,735 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+{
+  if (typeof Components != "undefined") {
+    // We do not wish osfile_unix_back.jsm to be used directly as a main thread
+    // module yet. When time comes, it will be loaded by a combination of
+    // a main thread front-end/worker thread implementation that makes sure
+    // that we are not executing synchronous IO code in the main thread.
+
+    throw new Error("osfile_unix_back.jsm cannot be used from the main thread yet");
+  }
+  (function(exports) {
+     "use strict";
+     if (exports.OS && exports.OS.Unix && exports.OS.Unix.File) {
+       return; // Avoid double initialization
+     }
+
+     let SharedAll =
+       require("resource://gre/modules/osfile/osfile_shared_allthreads.jsm");
+     let SysAll =
+       require("resource://gre/modules/osfile/osfile_unix_allthreads.jsm");
+     let LOG = SharedAll.LOG.bind(SharedAll, "Unix", "back");
+     let libc = SysAll.libc;
+     let Const = SharedAll.Constants.libc;
+
+     /**
+      * Initialize the Unix module.
+      *
+      * @param {function=} declareFFI
+      */
+     // FIXME: Both |init| and |aDeclareFFI| are deprecated, we should remove them
+     let init = function init(aDeclareFFI) {
+       let declareFFI;
+       if (aDeclareFFI) {
+         declareFFI = aDeclareFFI.bind(null, libc);
+       } else {
+         declareFFI = SysAll.declareFFI;
+       }
+       let declareLazyFFI = SharedAll.declareLazyFFI;
+
+       // Initialize types that require additional OS-specific
+       // support - either finalization or matching against
+       // OS-specific constants.
+       let Type = Object.create(SysAll.Type);
+       let SysFile = exports.OS.Unix.File = { Type: Type };
+
+       /**
+        * A file descriptor.
+        */
+       Type.fd = Type.int.withName("fd");
+       Type.fd.importFromC = function importFromC(fd_int) {
+         return ctypes.CDataFinalizer(fd_int, SysFile._close);
+       };
+
+
+       /**
+        * A C integer holding -1 in case of error or a file descriptor
+        * in case of success.
+        */
+       Type.negativeone_or_fd = Type.fd.withName("negativeone_or_fd");
+       Type.negativeone_or_fd.importFromC =
+         function importFromC(fd_int) {
+           if (fd_int == -1) {
+             return -1;
+           }
+           return ctypes.CDataFinalizer(fd_int, SysFile._close);
+         };
+
+       /**
+        * A C integer holding -1 in case of error or a meaningless value
+        * in case of success.
+        */
+       Type.negativeone_or_nothing =
+         Type.int.withName("negativeone_or_nothing");
+
+       /**
+        * A C integer holding -1 in case of error or a positive integer
+        * in case of success.
+        */
+       Type.negativeone_or_ssize_t =
+         Type.ssize_t.withName("negativeone_or_ssize_t");
+
+       /**
+        * Various libc integer types
+        */
+       Type.mode_t =
+         Type.intn_t(Const.OSFILE_SIZEOF_MODE_T).withName("mode_t");
+       Type.uid_t =
+         Type.intn_t(Const.OSFILE_SIZEOF_UID_T).withName("uid_t");
+       Type.gid_t =
+         Type.intn_t(Const.OSFILE_SIZEOF_GID_T).withName("gid_t");
+
+       /**
+        * Type |time_t|
+        */
+       Type.time_t =
+         Type.intn_t(Const.OSFILE_SIZEOF_TIME_T).withName("time_t");
+
+       // Structure |dirent|
+       // Building this type is rather complicated, as its layout varies between
+       // variants of Unix. For this reason, we rely on a number of constants
+       // (computed in C from the C data structures) that give us the layout.
+       // The structure we compute looks like
+       //  { int8_t[...] before_d_type; // ignored content
+       //    int8_t      d_type       ;
+       //    int8_t[...] before_d_name; // ignored content
+       //    char[...]   d_name;
+       //    };
+       {
+         let d_name_extra_size = 0;
+         if (Const.OSFILE_SIZEOF_DIRENT_D_NAME < 8) {
+           // d_name is defined like "char d_name[1];" on some platforms
+           // (e.g. Solaris), we need to give it more size for our structure.
+           d_name_extra_size = 256;
+         }
+
+         let dirent = new SharedAll.HollowStructure("dirent",
+           Const.OSFILE_SIZEOF_DIRENT + d_name_extra_size);
+         if (Const.OSFILE_OFFSETOF_DIRENT_D_TYPE != undefined) {
+           // |dirent| doesn't have d_type on some platforms (e.g. Solaris).
+           dirent.add_field_at(Const.OSFILE_OFFSETOF_DIRENT_D_TYPE,
+             "d_type", ctypes.uint8_t);
+         }
+         dirent.add_field_at(Const.OSFILE_OFFSETOF_DIRENT_D_NAME,
+           "d_name", ctypes.ArrayType(ctypes.char,
+             Const.OSFILE_SIZEOF_DIRENT_D_NAME + d_name_extra_size));
+
+         // We now have built |dirent|.
+         Type.dirent = dirent.getType();
+       }
+       Type.null_or_dirent_ptr =
+         new SharedAll.Type("null_of_dirent",
+                  Type.dirent.out_ptr.implementation);
+
+       // Structure |stat|
+       // Same technique
+       {
+         let stat = new SharedAll.HollowStructure("stat",
+           Const.OSFILE_SIZEOF_STAT);
+         stat.add_field_at(Const.OSFILE_OFFSETOF_STAT_ST_MODE,
+                        "st_mode", Type.mode_t.implementation);
+         stat.add_field_at(Const.OSFILE_OFFSETOF_STAT_ST_UID,
+                          "st_uid", Type.uid_t.implementation);
+         stat.add_field_at(Const.OSFILE_OFFSETOF_STAT_ST_GID,
+                          "st_gid", Type.gid_t.implementation);
+
+         // Here, things get complicated with different data structures.
+         // Some platforms have |time_t st_atime| and some platforms have
+         // |timespec st_atimespec|. However, since |timespec| starts with
+         // a |time_t|, followed by nanoseconds, we just cheat and pretend
+         // that everybody has |time_t st_atime|, possibly followed by padding
+         stat.add_field_at(Const.OSFILE_OFFSETOF_STAT_ST_ATIME,
+                          "st_atime", Type.time_t.implementation);
+         stat.add_field_at(Const.OSFILE_OFFSETOF_STAT_ST_MTIME,
+                          "st_mtime", Type.time_t.implementation);
+         stat.add_field_at(Const.OSFILE_OFFSETOF_STAT_ST_CTIME,
+                          "st_ctime", Type.time_t.implementation);
+
+         // To complicate further, MacOS and some BSDs have a field |birthtime|
+         if ("OSFILE_OFFSETOF_STAT_ST_BIRTHTIME" in Const) {
+           stat.add_field_at(Const.OSFILE_OFFSETOF_STAT_ST_BIRTHTIME,
+                             "st_birthtime", Type.time_t.implementation);
+         }
+
+         stat.add_field_at(Const.OSFILE_OFFSETOF_STAT_ST_SIZE,
+                        "st_size", Type.off_t.implementation);
+         Type.stat = stat.getType();
+       }
+
+       // Structure |DIR|
+       if ("OSFILE_SIZEOF_DIR" in Const) {
+         // On platforms for which we need to access the fields of DIR
+         // directly (e.g. because certain functions are implemented
+         // as macros), we need to define DIR as a hollow structure.
+         let DIR = new SharedAll.HollowStructure(
+           "DIR",
+           Const.OSFILE_SIZEOF_DIR);
+
+         DIR.add_field_at(
+           Const.OSFILE_OFFSETOF_DIR_DD_FD,
+           "dd_fd",
+           Type.fd.implementation);
+
+         Type.DIR = DIR.getType();
+       } else {
+         // On other platforms, we keep DIR as a blackbox
+         Type.DIR =
+           new SharedAll.Type("DIR",
+             ctypes.StructType("DIR"));
+       }
+
+       Type.null_or_DIR_ptr =
+         Type.DIR.out_ptr.withName("null_or_DIR*");
+       Type.null_or_DIR_ptr.importFromC = function importFromC(dir) {
+         if (dir == null || dir.isNull()) {
+           return null;
+         }
+         return ctypes.CDataFinalizer(dir, SysFile._close_dir);
+       };
+
+       // Structure |timeval|
+       {
+         let timeval = new SharedAll.HollowStructure(
+           "timeval",
+           Const.OSFILE_SIZEOF_TIMEVAL);
+         timeval.add_field_at(
+           Const.OSFILE_OFFSETOF_TIMEVAL_TV_SEC,
+           "tv_sec",
+           Type.long.implementation);
+         timeval.add_field_at(
+           Const.OSFILE_OFFSETOF_TIMEVAL_TV_USEC,
+           "tv_usec",
+           Type.long.implementation);
+         Type.timeval = timeval.getType();
+         Type.timevals = new SharedAll.Type("two timevals",
+           ctypes.ArrayType(Type.timeval.implementation, 2));
+       }
+
+       // Types fsblkcnt_t and fsfilcnt_t, used by structure |statvfs|
+       Type.fsblkcnt_t =
+         Type.uintn_t(Const.OSFILE_SIZEOF_FSBLKCNT_T).withName("fsblkcnt_t");
+
+       // Structure |statvfs|
+       // Use an hollow structure
+       {
+         let statvfs = new SharedAll.HollowStructure("statvfs",
+           Const.OSFILE_SIZEOF_STATVFS);
+
+         statvfs.add_field_at(Const.OSFILE_OFFSETOF_STATVFS_F_BSIZE,
+                        "f_bsize", Type.unsigned_long.implementation);
+         statvfs.add_field_at(Const.OSFILE_OFFSETOF_STATVFS_F_BAVAIL,
+                        "f_bavail", Type.fsblkcnt_t.implementation);
+
+         Type.statvfs = statvfs.getType();
+       }
+
+       // Declare libc functions as functions of |OS.Unix.File|
+
+       // Finalizer-related functions
+       libc.declareLazy(SysFile, "_close",
+                        "close", ctypes.default_abi,
+                        /*return */ctypes.int,
+                        /*fd*/     ctypes.int);
+
+       SysFile.close = function close(fd) {
+         // Detach the finalizer and call |_close|.
+         return fd.dispose();
+       };
+
+       libc.declareLazy(SysFile, "_close_dir",
+                        "closedir", ctypes.default_abi,
+                        /*return */ctypes.int,
+                        /*dirp*/   Type.DIR.in_ptr.implementation);
+
+       SysFile.closedir = function closedir(fd) {
+         // Detach the finalizer and call |_close_dir|.
+         return fd.dispose();
+       };
+
+       {
+         // Symbol free() is special.
+         // We override the definition of free() on several platforms.
+         let default_lib = new SharedAll.Library("default_lib",
+                                                 "a.out");
+
+         // On platforms for which we override free(), nspr defines
+         // a special library name "a.out" that will resolve to the
+         // correct implementation free().
+         // If it turns out we don't have an a.out library or a.out
+         // doesn't contain free, use the ordinary libc free.
+
+         default_lib.declareLazyWithFallback(libc, SysFile, "free",
+           "free", ctypes.default_abi,
+           /*return*/ ctypes.void_t,
+           /*ptr*/    ctypes.voidptr_t);
+       }
+
+
+       // Other functions
+       libc.declareLazyFFI(SysFile,  "access",
+                           "access", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_nothing,
+                           /*path*/   Type.path,
+                           /*mode*/   Type.int);
+
+       libc.declareLazyFFI(SysFile,  "chdir",
+                           "chdir", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_nothing,
+                           /*path*/   Type.path);
+
+       libc.declareLazyFFI(SysFile,  "chmod",
+                           "chmod", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_nothing,
+                           /*path*/   Type.path,
+                           /*mode*/   Type.mode_t);
+
+       libc.declareLazyFFI(SysFile,  "chown",
+                           "chown", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_nothing,
+                           /*path*/   Type.path,
+                           /*uid*/    Type.uid_t,
+                           /*gid*/    Type.gid_t);
+
+       libc.declareLazyFFI(SysFile,  "copyfile",
+                           "copyfile", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_nothing,
+                           /*source*/ Type.path,
+                           /*dest*/   Type.path,
+                           /*state*/  Type.void_t.in_ptr, // Ignored atm
+                           /*flags*/  Type.uint32_t);
+
+       libc.declareLazyFFI(SysFile,  "dup",
+                           "dup", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_fd,
+                           /*fd*/     Type.fd);
+
+       if ("OSFILE_SIZEOF_DIR" in Const) {
+         // On platforms for which |dirfd| is a macro
+         SysFile.dirfd =
+           function dirfd(DIRp) {
+             return Type.DIR.in_ptr.implementation(DIRp).contents.dd_fd;
+           };
+       } else {
+         // On platforms for which |dirfd| is a function
+         libc.declareLazyFFI(SysFile,  "dirfd",
+                             "dirfd", ctypes.default_abi,
+                             /*return*/ Type.negativeone_or_fd,
+                             /*dir*/    Type.DIR.in_ptr);
+       }
+
+       libc.declareLazyFFI(SysFile,  "chdir",
+                           "chdir", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_nothing,
+                           /*path*/   Type.path);
+
+       libc.declareLazyFFI(SysFile,  "fchdir",
+                           "fchdir", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_nothing,
+                           /*fd*/     Type.fd);
+
+       libc.declareLazyFFI(SysFile,  "fchmod",
+                           "fchmod", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_nothing,
+                           /*fd*/     Type.fd,
+                           /*mode*/   Type.mode_t);
+
+       libc.declareLazyFFI(SysFile,  "fchown",
+                           "fchown", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_nothing,
+                           /*fd*/     Type.fd,
+                           /*uid_t*/  Type.uid_t,
+                           /*gid_t*/  Type.gid_t);
+
+       libc.declareLazyFFI(SysFile,  "fsync",
+                           "fsync", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_nothing,
+                           /*fd*/     Type.fd);
+
+       libc.declareLazyFFI(SysFile,  "getcwd",
+                           "getcwd", ctypes.default_abi,
+                           /*return*/ Type.out_path,
+                           /*buf*/    Type.out_path,
+                           /*size*/   Type.size_t);
+
+       libc.declareLazyFFI(SysFile,  "getwd",
+                           "getwd", ctypes.default_abi,
+                           /*return*/ Type.out_path,
+                           /*buf*/    Type.out_path);
+
+       // Two variants of |getwd| which allocate the memory
+       // dynamically.
+
+       // Linux/Android version
+       libc.declareLazyFFI(SysFile,  "get_current_dir_name",
+                           "get_current_dir_name", ctypes.default_abi,
+                           /*return*/ Type.out_path.releaseWithLazy(() =>
+                             SysFile.free
+                           ));
+
+       // MacOS/BSD version (will return NULL on Linux/Android)
+       libc.declareLazyFFI(SysFile,  "getwd_auto",
+                           "getwd", ctypes.default_abi,
+                           /*return*/ Type.out_path.releaseWithLazy(() =>
+                             SysFile.free
+                           ),
+                           /*buf*/    Type.void_t.out_ptr);
+
+       libc.declareLazyFFI(SysFile,  "fdatasync",
+                           "fdatasync", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_nothing,
+                           /*fd*/     Type.fd); // Note: MacOS/BSD-specific
+
+       libc.declareLazyFFI(SysFile,  "ftruncate",
+                           "ftruncate", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_nothing,
+                           /*fd*/     Type.fd,
+                           /*length*/ Type.off_t);
+
+
+       libc.declareLazyFFI(SysFile,  "lchown",
+                           "lchown", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_nothing,
+                           /*path*/   Type.path,
+                           /*uid_t*/  Type.uid_t,
+                           /*gid_t*/  Type.gid_t);
+
+       libc.declareLazyFFI(SysFile,  "link",
+                           "link", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_nothing,
+                           /*source*/ Type.path,
+                           /*dest*/   Type.path);
+
+       libc.declareLazyFFI(SysFile,  "lseek",
+                           "lseek", ctypes.default_abi,
+                           /*return*/ Type.off_t,
+                           /*fd*/     Type.fd,
+                           /*offset*/ Type.off_t,
+                           /*whence*/ Type.int);
+
+       libc.declareLazyFFI(SysFile,  "mkdir",
+                           "mkdir", ctypes.default_abi,
+                           /*return*/ Type.int,
+                           /*path*/ Type.path,
+                           /*mode*/ Type.int);
+
+       libc.declareLazyFFI(SysFile,  "mkstemp",
+                           "mkstemp", ctypes.default_abi,
+                           /*return*/   Type.fd,
+                           /*template*/ Type.out_path);
+
+       libc.declareLazyFFI(SysFile,  "open",
+                           "open", ctypes.default_abi,
+                           /*return*/ Type.negativeone_or_fd,
+                           /*path*/   Type.path,
+                           /*oflags*/ Type.int,
+                           /*mode*/   Type.int);
+
+       if (OS.Constants.Sys.Name == "NetBSD") {
+          libc.declareLazyFFI(SysFile,  "opendir",
+                              "__opendir30", ctypes.default_abi,
+                   /*return*/ Type.null_or_DIR_ptr,
+                   /*path*/   Type.path);
+       } else {
+          libc.declareLazyFFI(SysFile,  "opendir",
+                              "opendir", ctypes.default_abi,
+                    /*return*/ Type.null_or_DIR_ptr,
+                    /*path*/   Type.path);
+       }
+
+       libc.declareLazyFFI(SysFile,  "pread",
+                               "pread", ctypes.default_abi,
+                    /*return*/ Type.negativeone_or_ssize_t,
+                    /*fd*/     Type.fd,
+                    /*buf*/    Type.void_t.out_ptr,
+                    /*nbytes*/ Type.size_t,
+                    /*offset*/ Type.off_t);
+
+       libc.declareLazyFFI(SysFile,  "pwrite",
+                               "pwrite", ctypes.default_abi,
+                    /*return*/ Type.negativeone_or_ssize_t,
+                    /*fd*/     Type.fd,
+                    /*buf*/    Type.void_t.in_ptr,
+                    /*nbytes*/ Type.size_t,
+                    /*offset*/ Type.off_t);
+
+       libc.declareLazyFFI(SysFile,  "read",
+                              "read", ctypes.default_abi,
+                    /*return*/Type.negativeone_or_ssize_t,
+                    /*fd*/    Type.fd,
+                    /*buf*/   Type.void_t.out_ptr,
+                    /*nbytes*/Type.size_t);
+
+       libc.declareLazyFFI(SysFile,  "posix_fadvise",
+                               "posix_fadvise", ctypes.default_abi,
+                    /*return*/ Type.int,
+                    /*fd*/     Type.fd,
+                    /*offset*/ Type.off_t,
+                    /*len*/    Type.off_t,
+                    /*advise*/ Type.int);
+
+       if (Const._DARWIN_FEATURE_64_BIT_INODE) {
+         // Special case for MacOS X 10.5+
+         // Symbol name "readdir" still exists but is used for a
+         // deprecated function that does not match the
+         // constants of |Const|.
+         libc.declareLazyFFI(SysFile,  "readdir",
+                                "readdir$INODE64", ctypes.default_abi,
+                     /*return*/ Type.null_or_dirent_ptr,
+                      /*dir*/   Type.DIR.in_ptr); // For MacOS X
+       } else if (OS.Constants.Sys.Name == "NetBSD") {
+         libc.declareLazyFFI(SysFile,  "readdir",
+                                "__readdir30", ctypes.default_abi,
+                      /*return*/Type.null_or_dirent_ptr,
+                      /*dir*/   Type.DIR.in_ptr); // Other Unices
+       } else {
+         libc.declareLazyFFI(SysFile,  "readdir",
+                                "readdir", ctypes.default_abi,
+                      /*return*/Type.null_or_dirent_ptr,
+                      /*dir*/   Type.DIR.in_ptr); // Other Unices
+       }
+
+       libc.declareLazyFFI(SysFile,  "rename",
+                               "rename", ctypes.default_abi,
+                    /*return*/ Type.negativeone_or_nothing,
+                    /*old*/    Type.path,
+                    /*new*/    Type.path);
+
+       libc.declareLazyFFI(SysFile,  "rmdir",
+                               "rmdir", ctypes.default_abi,
+                    /*return*/ Type.int,
+                    /*path*/   Type.path);
+
+       libc.declareLazyFFI(SysFile,  "splice",
+                               "splice", ctypes.default_abi,
+                    /*return*/ Type.long,
+                    /*fd_in*/  Type.fd,
+                    /*off_in*/ Type.off_t.in_ptr,
+                    /*fd_out*/ Type.fd,
+                    /*off_out*/Type.off_t.in_ptr,
+                    /*len*/    Type.size_t,
+                    /*flags*/  Type.unsigned_int); // Linux/Android-specific
+
+       libc.declareLazyFFI(SysFile,  "statfs",
+                               "statfs", ctypes.default_abi,
+                    /*return*/ Type.negativeone_or_nothing,
+                    /*path*/   Type.path,
+                    /*buf*/    Type.statvfs.out_ptr); // Android,B2G
+
+       libc.declareLazyFFI(SysFile,  "statvfs",
+                               "statvfs", ctypes.default_abi,
+                    /*return*/ Type.negativeone_or_nothing,
+                    /*path*/   Type.path,
+                    /*buf*/    Type.statvfs.out_ptr); // Other platforms
+
+       libc.declareLazyFFI(SysFile,  "symlink",
+                               "symlink", ctypes.default_abi,
+                    /*return*/ Type.negativeone_or_nothing,
+                    /*source*/ Type.path,
+                    /*dest*/   Type.path);
+
+       libc.declareLazyFFI(SysFile,  "truncate",
+                              "truncate", ctypes.default_abi,
+                    /*return*/Type.negativeone_or_nothing,
+                    /*path*/  Type.path,
+                    /*length*/ Type.off_t);
+
+       libc.declareLazyFFI(SysFile,  "unlink",
+                           "unlink", ctypes.default_abi,
+                    /*return*/ Type.negativeone_or_nothing,
+                    /*path*/ Type.path);
+
+       libc.declareLazyFFI(SysFile,  "write",
+                           "write", ctypes.default_abi,
+                    /*return*/ Type.negativeone_or_ssize_t,
+                    /*fd*/     Type.fd,
+                    /*buf*/    Type.void_t.in_ptr,
+                    /*nbytes*/ Type.size_t);
+
+       // Weird cases that require special treatment
+
+       // OSes use a variety of hacks to differentiate between
+       // 32-bits and 64-bits versions of |stat|, |lstat|, |fstat|.
+       if (Const._DARWIN_FEATURE_64_BIT_INODE) {
+         // MacOS X 64-bits
+         libc.declareLazyFFI(SysFile,  "stat",
+                             "stat$INODE64", ctypes.default_abi,
+                      /*return*/ Type.negativeone_or_nothing,
+                      /*path*/   Type.path,
+                      /*buf*/    Type.stat.out_ptr
+                     );
+         libc.declareLazyFFI(SysFile,  "lstat",
+                             "lstat$INODE64", ctypes.default_abi,
+                      /*return*/ Type.negativeone_or_nothing,
+                      /*path*/   Type.path,
+                      /*buf*/    Type.stat.out_ptr
+                     );
+         libc.declareLazyFFI(SysFile,  "fstat",
+                             "fstat$INODE64", ctypes.default_abi,
+                      /*return*/ Type.negativeone_or_nothing,
+                      /*path*/   Type.fd,
+                      /*buf*/    Type.stat.out_ptr
+                     );
+       } else if (Const._STAT_VER != undefined) {
+         const ver = Const._STAT_VER;
+         let xstat_name, lxstat_name, fxstat_name;
+         if (OS.Constants.Sys.Name == "SunOS") {
+           // Solaris
+           xstat_name = "_xstat";
+           lxstat_name = "_lxstat";
+           fxstat_name = "_fxstat";
+         } else {
+           // Linux, all widths
+           xstat_name = "__xstat";
+           lxstat_name = "__lxstat";
+           fxstat_name = "__fxstat";
+         }
+
+         let Stat = {};
+         libc.declareLazyFFI(Stat,  "xstat",
+                             xstat_name, ctypes.default_abi,
+                      /*return*/    Type.negativeone_or_nothing,
+                      /*_stat_ver*/ Type.int,
+                      /*path*/      Type.path,
+                      /*buf*/       Type.stat.out_ptr);
+         libc.declareLazyFFI(Stat,  "lxstat",
+                             lxstat_name, ctypes.default_abi,
+                      /*return*/    Type.negativeone_or_nothing,
+                      /*_stat_ver*/ Type.int,
+                      /*path*/      Type.path,
+                      /*buf*/       Type.stat.out_ptr);
+         libc.declareLazyFFI(Stat, "fxstat",
+                             fxstat_name, ctypes.default_abi,
+                      /*return*/    Type.negativeone_or_nothing,
+                      /*_stat_ver*/ Type.int,
+                      /*fd*/        Type.fd,
+                      /*buf*/       Type.stat.out_ptr);
+
+
+         SysFile.stat = function stat(path, buf) {
+           return Stat.xstat(ver, path, buf);
+         };
+
+         SysFile.lstat = function lstat(path, buf) {
+           return Stat.lxstat(ver, path, buf);
+         };
+
+         SysFile.fstat = function fstat(fd, buf) {
+           return Stat.fxstat(ver, fd, buf);
+         };
+       } else if (OS.Constants.Sys.Name == "NetBSD") {
+         // NetBSD 5.0 and newer
+         libc.declareLazyFFI(SysFile,  "stat",
+                             "__stat50", ctypes.default_abi,
+                      /*return*/ Type.negativeone_or_nothing,
+                      /*path*/   Type.path,
+                      /*buf*/    Type.stat.out_ptr
+                     );
+         libc.declareLazyFFI(SysFile,  "lstat",
+                             "__lstat50", ctypes.default_abi,
+                      /*return*/ Type.negativeone_or_nothing,
+                      /*path*/   Type.path,
+                      /*buf*/    Type.stat.out_ptr
+                     );
+         libc.declareLazyFFI(SysFile,  "fstat",
+                             "__fstat50", ctypes.default_abi,
+                      /*return*/ Type.negativeone_or_nothing,
+                      /*fd*/     Type.fd,
+                      /*buf*/    Type.stat.out_ptr
+                     );
+       } else {
+         // Mac OS X 32-bits, other Unix
+         libc.declareLazyFFI(SysFile,  "stat",
+                             "stat", ctypes.default_abi,
+                      /*return*/ Type.negativeone_or_nothing,
+                      /*path*/   Type.path,
+                      /*buf*/    Type.stat.out_ptr
+                     );
+         libc.declareLazyFFI(SysFile,  "lstat",
+                             "lstat", ctypes.default_abi,
+                      /*return*/ Type.negativeone_or_nothing,
+                      /*path*/   Type.path,
+                      /*buf*/    Type.stat.out_ptr
+                     );
+         libc.declareLazyFFI(SysFile,  "fstat",
+                             "fstat", ctypes.default_abi,
+                      /*return*/ Type.negativeone_or_nothing,
+                      /*fd*/     Type.fd,
+                      /*buf*/    Type.stat.out_ptr
+                     );
+       }
+
+       // We cannot make a C array of CDataFinalizer, so
+       // pipe cannot be directly defined as a C function.
+
+       let Pipe = {};
+       libc.declareLazyFFI(Pipe, "_pipe",
+         "pipe", ctypes.default_abi,
+         /*return*/ Type.negativeone_or_nothing,
+         /*fds*/    new SharedAll.Type("two file descriptors",
+             ctypes.ArrayType(ctypes.int, 2)));
+
+       // A shared per-thread buffer used to communicate with |pipe|
+       let _pipebuf = new (ctypes.ArrayType(ctypes.int, 2))();
+
+       SysFile.pipe = function pipe(array) {
+         let result = Pipe._pipe(_pipebuf);
+         if (result == -1) {
+           return result;
+         }
+         array[0] = ctypes.CDataFinalizer(_pipebuf[0], SysFile._close);
+         array[1] = ctypes.CDataFinalizer(_pipebuf[1], SysFile._close);
+         return result;
+       };
+
+       if (OS.Constants.Sys.Name == "NetBSD") {
+           libc.declareLazyFFI(SysFile, "utimes",
+                               "__utimes50", ctypes.default_abi,
+                      /*return*/     Type.negativeone_or_nothing,
+                      /*path*/       Type.path,
+                      /*timeval[2]*/ Type.timevals.out_ptr
+                      );
+       } else {
+           libc.declareLazyFFI(SysFile, "utimes",
+                               "utimes", ctypes.default_abi,
+                      /*return*/     Type.negativeone_or_nothing,
+                      /*path*/       Type.path,
+                      /*timeval[2]*/ Type.timevals.out_ptr
+                      );
+       }
+       if (OS.Constants.Sys.Name == "NetBSD") {
+           libc.declareLazyFFI(SysFile, "futimes",
+                               "__futimes50", ctypes.default_abi,
+                      /*return*/     Type.negativeone_or_nothing,
+                      /*fd*/         Type.fd,
+                      /*timeval[2]*/ Type.timevals.out_ptr
+                      );
+       } else {
+           libc.declareLazyFFI(SysFile, "futimes",
+                               "futimes", ctypes.default_abi,
+                      /*return*/     Type.negativeone_or_nothing,
+                      /*fd*/         Type.fd,
+                      /*timeval[2]*/ Type.timevals.out_ptr
+                      );
+       }
+     };
+
+     exports.OS.Unix = {
+       File: {
+         _init: init
+       }
+     };
+   })(this);
+}

toolkit/components/osfile/modules/osfile_win_allthreads.jsm

@@ -0,0 +1,425 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This module defines the thread-agnostic components of the Win version
+ * of OS.File. It depends on the thread-agnostic cross-platform components
+ * of OS.File.
+ *
+ * It serves the following purposes:
+ * - open kernel32;
+ * - define OS.Shared.Win.Error;
+ * - define a few constants and types that need to be defined on all platforms.
+ *
+ * This module can be:
+ * - opened from the main thread as a jsm module;
+ * - opened from a chrome worker through require().
+ */
+
+"use strict";
+
+var SharedAll;
+if (typeof Components != "undefined") {
+  let Cu = Components.utils;
+  // Module is opened as a jsm module
+  Cu.import("resource://gre/modules/ctypes.jsm", this);
+
+  SharedAll = {};
+  Cu.import("resource://gre/modules/osfile/osfile_shared_allthreads.jsm", SharedAll);
+  this.exports = {};
+} else if (typeof module != "undefined" && typeof require != "undefined") {
+  // Module is loaded with require()
+  SharedAll = require("resource://gre/modules/osfile/osfile_shared_allthreads.jsm");
+} else {
+  throw new Error("Please open this module with Component.utils.import or with require()");
+}
+
+var LOG = SharedAll.LOG.bind(SharedAll, "Win", "allthreads");
+var Const = SharedAll.Constants.Win;
+
+// Open libc
+var libc = new SharedAll.Library("libc", "kernel32.dll");
+exports.libc = libc;
+
+// Define declareFFI
+var declareFFI = SharedAll.declareFFI.bind(null, libc);
+exports.declareFFI = declareFFI;
+
+var Scope = {};
+
+// Define Error
+libc.declareLazy(Scope, "FormatMessage",
+                 "FormatMessageW", ctypes.winapi_abi,
+                 /*return*/ ctypes.uint32_t,
+                 /*flags*/  ctypes.uint32_t,
+                 /*source*/ ctypes.voidptr_t,
+                 /*msgid*/  ctypes.uint32_t,
+                 /*langid*/ ctypes.uint32_t,
+                 /*buf*/    ctypes.char16_t.ptr,
+                 /*size*/   ctypes.uint32_t,
+                 /*Arguments*/ctypes.voidptr_t);
+
+/**
+ * A File-related error.
+ *
+ * To obtain a human-readable error message, use method |toString|.
+ * To determine the cause of the error, use the various |becauseX|
+ * getters. To determine the operation that failed, use field
+ * |operation|.
+ *
+ * Additionally, this implementation offers a field
+ * |winLastError|, which holds the OS-specific error
+ * constant. If you need this level of detail, you may match the value
+ * of this field against the error constants of |OS.Constants.Win|.
+ *
+ * @param {string=} operation The operation that failed. If unspecified,
+ * the name of the calling function is taken to be the operation that
+ * failed.
+ * @param {number=} lastError The OS-specific constant detailing the
+ * reason of the error. If unspecified, this is fetched from the system
+ * status.
+ * @param {string=} path The file path that manipulated. If unspecified,
+ * assign the empty string.
+ *
+ * @constructor
+ * @extends {OS.Shared.Error}
+ */
+var OSError = function OSError(operation = "unknown operation",
+                               lastError = ctypes.winLastError, path = "") {
+  operation = operation;
+  SharedAll.OSError.call(this, operation, path);
+  this.winLastError = lastError;
+};
+OSError.prototype = Object.create(SharedAll.OSError.prototype);
+OSError.prototype.toString = function toString() {
+  let buf = new (ctypes.ArrayType(ctypes.char16_t, 1024))();
+  let result = Scope.FormatMessage(
+    Const.FORMAT_MESSAGE_FROM_SYSTEM |
+    Const.FORMAT_MESSAGE_IGNORE_INSERTS,
+    null,
+    /* The error number */ this.winLastError,
+    /* Default language */ 0,
+    /* Output buffer*/     buf,
+    /* Minimum size of buffer */ 1024,
+    /* Format args*/       null
+  );
+  if (!result) {
+    buf = "additional error " +
+      ctypes.winLastError +
+      " while fetching system error message";
+  }
+  return "Win error " + this.winLastError + " during operation "
+    + this.operation + (this.path? " on file " + this.path : "") +
+    " (" + buf.readString() + ")";
+};
+OSError.prototype.toMsg = function toMsg() {
+  return OSError.toMsg(this);
+};
+
+/**
+ * |true| if the error was raised because a file or directory
+ * already exists, |false| otherwise.
+ */
+Object.defineProperty(OSError.prototype, "becauseExists", {
+  get: function becauseExists() {
+    return this.winLastError == Const.ERROR_FILE_EXISTS ||
+      this.winLastError == Const.ERROR_ALREADY_EXISTS;
+  }
+});
+/**
+ * |true| if the error was raised because a file or directory
+ * does not exist, |false| otherwise.
+ */
+Object.defineProperty(OSError.prototype, "becauseNoSuchFile", {
+  get: function becauseNoSuchFile() {
+    return this.winLastError == Const.ERROR_FILE_NOT_FOUND ||
+      this.winLastError == Const.ERROR_PATH_NOT_FOUND;
+  }
+});
+/**
+ * |true| if the error was raised because a directory is not empty
+ * does not exist, |false| otherwise.
+ */
+Object.defineProperty(OSError.prototype, "becauseNotEmpty", {
+  get: function becauseNotEmpty() {
+    return this.winLastError == Const.ERROR_DIR_NOT_EMPTY;
+  }
+});
+/**
+ * |true| if the error was raised because a file or directory
+ * is closed, |false| otherwise.
+ */
+Object.defineProperty(OSError.prototype, "becauseClosed", {
+  get: function becauseClosed() {
+    return this.winLastError == Const.ERROR_INVALID_HANDLE;
+  }
+});
+/**
+ * |true| if the error was raised because permission is denied to
+ * access a file or directory, |false| otherwise.
+ */
+Object.defineProperty(OSError.prototype, "becauseAccessDenied", {
+  get: function becauseAccessDenied() {
+    return this.winLastError == Const.ERROR_ACCESS_DENIED;
+  }
+});
+/**
+ * |true| if the error was raised because some invalid argument was passed,
+ * |false| otherwise.
+ */
+Object.defineProperty(OSError.prototype, "becauseInvalidArgument", {
+  get: function becauseInvalidArgument() {
+    return this.winLastError == Const.ERROR_NOT_SUPPORTED ||
+           this.winLastError == Const.ERROR_BAD_ARGUMENTS;
+  }
+});
+
+/**
+ * Serialize an instance of OSError to something that can be
+ * transmitted across threads (not necessarily a string).
+ */
+OSError.toMsg = function toMsg(error) {
+  return {
+    exn: "OS.File.Error",
+    fileName: error.moduleName,
+    lineNumber: error.lineNumber,
+    stack: error.moduleStack,
+    operation: error.operation,
+    winLastError: error.winLastError,
+    path: error.path
+  };
+};
+
+/**
+ * Deserialize a message back to an instance of OSError
+ */
+OSError.fromMsg = function fromMsg(msg) {
+  let error = new OSError(msg.operation, msg.winLastError, msg.path);
+  error.stack = msg.stack;
+  error.fileName = msg.fileName;
+  error.lineNumber = msg.lineNumber;
+  return error;
+};
+exports.Error = OSError;
+
+/**
+ * Code shared by implementation of File.Info on Windows
+ *
+ * @constructor
+ */
+var AbstractInfo = function AbstractInfo(path, isDir, isSymLink, size,
+                                         winBirthDate,
+                                         lastAccessDate, lastWriteDate,
+                                         winAttributes) {
+  this._path = path;
+  this._isDir = isDir;
+  this._isSymLink = isSymLink;
+  this._size = size;
+  this._winBirthDate = winBirthDate;
+  this._lastAccessDate = lastAccessDate;
+  this._lastModificationDate = lastWriteDate;
+  this._winAttributes = winAttributes;
+};
+
+AbstractInfo.prototype = {
+  /**
+   * The path of the file, used for error-reporting.
+   *
+   * @type {string}
+   */
+  get path() {
+    return this._path;
+  },
+  /**
+   * |true| if this file is a directory, |false| otherwise
+   */
+  get isDir() {
+    return this._isDir;
+  },
+  /**
+   * |true| if this file is a symbolic link, |false| otherwise
+   */
+  get isSymLink() {
+    return this._isSymLink;
+  },
+  /**
+   * The size of the file, in bytes.
+   *
+   * Note that the result may be |NaN| if the size of the file cannot be
+   * represented in JavaScript.
+   *
+   * @type {number}
+   */
+  get size() {
+    return this._size;
+  },
+  // Deprecated
+  get creationDate() {
+    return this._winBirthDate;
+  },
+  /**
+   * The date of creation of this file.
+   *
+   * @type {Date}
+   */
+  get winBirthDate() {
+    return this._winBirthDate;
+  },
+  /**
+   * The date of last access to this file.
+   *
+   * Note that the definition of last access may depend on the underlying
+   * operating system and file system.
+   *
+   * @type {Date}
+   */
+  get lastAccessDate() {
+    return this._lastAccessDate;
+  },
+  /**
+   * The date of last modification of this file.
+   *
+   * Note that the definition of last access may depend on the underlying
+   * operating system and file system.
+   *
+   * @type {Date}
+   */
+  get lastModificationDate() {
+    return this._lastModificationDate;
+  },
+  /**
+   * The Object with following boolean properties of this file.
+   * {readOnly, system, hidden}
+   *
+   * @type {object}
+   */
+  get winAttributes() {
+    return this._winAttributes;
+  }
+};
+exports.AbstractInfo = AbstractInfo;
+
+/**
+ * Code shared by implementation of File.DirectoryIterator.Entry on Windows
+ *
+ * @constructor
+ */
+var AbstractEntry = function AbstractEntry(isDir, isSymLink, name,
+                                           winCreationDate, winLastWriteDate,
+                                           winLastAccessDate, path) {
+  this._isDir = isDir;
+  this._isSymLink = isSymLink;
+  this._name = name;
+  this._winCreationDate = winCreationDate;
+  this._winLastWriteDate = winLastWriteDate;
+  this._winLastAccessDate = winLastAccessDate;
+  this._path = path;
+};
+
+AbstractEntry.prototype = {
+  /**
+   * |true| if the entry is a directory, |false| otherwise
+   */
+  get isDir() {
+    return this._isDir;
+  },
+  /**
+   * |true| if the entry is a symbolic link, |false| otherwise
+   */
+  get isSymLink() {
+    return this._isSymLink;
+  },
+  /**
+   * The name of the entry.
+   * @type {string}
+   */
+  get name() {
+    return this._name;
+  },
+  /**
+   * The creation time of this file.
+   * @type {Date}
+   */
+  get winCreationDate() {
+    return this._winCreationDate;
+  },
+  /**
+   * The last modification time of this file.
+   * @type {Date}
+   */
+  get winLastWriteDate() {
+    return this._winLastWriteDate;
+  },
+  /**
+   * The last access time of this file.
+   * @type {Date}
+   */
+  get winLastAccessDate() {
+    return this._winLastAccessDate;
+  },
+  /**
+   * The full path of the entry
+   * @type {string}
+   */
+  get path() {
+    return this._path;
+  }
+};
+exports.AbstractEntry = AbstractEntry;
+
+// Special constants that need to be defined on all platforms
+
+exports.POS_START = Const.FILE_BEGIN;
+exports.POS_CURRENT = Const.FILE_CURRENT;
+exports.POS_END = Const.FILE_END;
+
+// Special types that need to be defined for communication
+// between threads
+var Type = Object.create(SharedAll.Type);
+exports.Type = Type;
+
+/**
+ * Native paths
+ *
+ * Under Windows, expressed as wide strings
+ */
+Type.path = Type.wstring.withName("[in] path");
+Type.out_path = Type.out_wstring.withName("[out] path");
+
+// Special constructors that need to be defined on all threads
+OSError.closed = function closed(operation, path) {
+  return new OSError(operation, Const.ERROR_INVALID_HANDLE, path);
+};
+
+OSError.exists = function exists(operation, path) {
+  return new OSError(operation, Const.ERROR_FILE_EXISTS, path);
+};
+
+OSError.noSuchFile = function noSuchFile(operation, path) {
+  return new OSError(operation, Const.ERROR_FILE_NOT_FOUND, path);
+};
+
+OSError.invalidArgument = function invalidArgument(operation) {
+  return new OSError(operation, Const.ERROR_NOT_SUPPORTED);
+};
+
+var EXPORTED_SYMBOLS = [
+  "declareFFI",
+  "libc",
+  "Error",
+  "AbstractInfo",
+  "AbstractEntry",
+  "Type",
+  "POS_START",
+  "POS_CURRENT",
+  "POS_END"
+];
+
+//////////// Boilerplate
+if (typeof Components != "undefined") {
+  this.EXPORTED_SYMBOLS = EXPORTED_SYMBOLS;
+  for (let symbol of EXPORTED_SYMBOLS) {
+    this[symbol] = exports[symbol];
+  }
+}

toolkit/components/osfile/modules/osfile_win_back.jsm

@@ -0,0 +1,437 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * This file can be used in the following contexts:
+ *
+ *  1. included from a non-osfile worker thread using importScript
+ *   (it serves to define a synchronous API for that worker thread)
+ *   (bug 707681)
+ *
+ *  2. included from the main thread using Components.utils.import
+ *   (it serves to define the asynchronous API, whose implementation
+ *    resides in the worker thread)
+ *   (bug 729057)
+ *
+ * 3. included from the osfile worker thread using importScript
+ *   (it serves to define the implementation of the asynchronous API)
+ *   (bug 729057)
+ */
+
+{
+  if (typeof Components != "undefined") {
+    // We do not wish osfile_win.jsm to be used directly as a main thread
+    // module yet. When time comes, it will be loaded by a combination of
+    // a main thread front-end/worker thread implementation that makes sure
+    // that we are not executing synchronous IO code in the main thread.
+
+    throw new Error("osfile_win.jsm cannot be used from the main thread yet");
+  }
+
+  (function(exports) {
+     "use strict";
+     if (exports.OS && exports.OS.Win && exports.OS.Win.File) {
+       return; // Avoid double initialization
+     }
+
+     let SharedAll = require("resource://gre/modules/osfile/osfile_shared_allthreads.jsm");
+     let SysAll = require("resource://gre/modules/osfile/osfile_win_allthreads.jsm");
+     let LOG = SharedAll.LOG.bind(SharedAll, "Unix", "back");
+     let libc = SysAll.libc;
+     let advapi32 = new SharedAll.Library("advapi32", "advapi32.dll");
+     let Const = SharedAll.Constants.Win;
+
+     /**
+      * Initialize the Windows module.
+      *
+      * @param {function=} declareFFI
+      */
+     // FIXME: Both |init| and |aDeclareFFI| are deprecated, we should remove them
+     let init = function init(aDeclareFFI) {
+       let declareFFI;
+       if (aDeclareFFI) {
+         declareFFI = aDeclareFFI.bind(null, libc);
+       } else {
+         declareFFI = SysAll.declareFFI;
+       }
+       let declareLazyFFI = SharedAll.declareLazyFFI;
+
+       // Initialize types that require additional OS-specific
+       // support - either finalization or matching against
+       // OS-specific constants.
+       let Type = Object.create(SysAll.Type);
+       let SysFile = exports.OS.Win.File = { Type: Type };
+
+       // Initialize types
+
+       /**
+        * A C integer holding INVALID_HANDLE_VALUE in case of error or
+        * a file descriptor in case of success.
+        */
+       Type.HANDLE =
+         Type.voidptr_t.withName("HANDLE");
+       Type.HANDLE.importFromC = function importFromC(maybe) {
+         if (Type.int.cast(maybe).value == INVALID_HANDLE) {
+           // Ensure that API clients can effectively compare against
+           // Const.INVALID_HANDLE_VALUE. Without this cast,
+           // == would always return |false|.
+           return INVALID_HANDLE;
+         }
+         return ctypes.CDataFinalizer(maybe, this.finalizeHANDLE);
+       };
+       Type.HANDLE.finalizeHANDLE = function placeholder() {
+         throw new Error("finalizeHANDLE should be implemented");
+       };
+       let INVALID_HANDLE = Const.INVALID_HANDLE_VALUE;
+
+       Type.file_HANDLE = Type.HANDLE.withName("file HANDLE");
+       SharedAll.defineLazyGetter(Type.file_HANDLE,
+         "finalizeHANDLE",
+         function() {
+           return SysFile._CloseHandle;
+         });
+
+       Type.find_HANDLE = Type.HANDLE.withName("find HANDLE");
+       SharedAll.defineLazyGetter(Type.find_HANDLE,
+         "finalizeHANDLE",
+         function() {
+           return SysFile._FindClose;
+         });
+
+       Type.DWORD = Type.uint32_t.withName("DWORD");
+
+       /* A special type used to represent flags passed as DWORDs to a function.
+        * In JavaScript, bitwise manipulation of numbers, such as or-ing flags,
+        * can produce negative numbers. Since DWORD is unsigned, these negative
+        * numbers simply cannot be converted to DWORD. For this reason, whenever
+        * bit manipulation is called for, you should rather use DWORD_FLAGS,
+        * which is represented as a signed integer, hence has the correct
+        * semantics.
+        */
+       Type.DWORD_FLAGS = Type.int32_t.withName("DWORD_FLAGS");
+
+       /**
+        * A C integer holding 0 in case of error or a positive integer
+        * in case of success.
+        */
+       Type.zero_or_DWORD =
+         Type.DWORD.withName("zero_or_DWORD");
+
+       /**
+        * A C integer holding 0 in case of error, any other value in
+        * case of success.
+        */
+       Type.zero_or_nothing =
+         Type.int.withName("zero_or_nothing");
+
+       /**
+        * A C integer holding flags related to NTFS security.
+        */
+       Type.SECURITY_ATTRIBUTES =
+         Type.void_t.withName("SECURITY_ATTRIBUTES");
+
+       /**
+        * A C integer holding pointers related to NTFS security.
+        */
+       Type.PSID =
+         Type.voidptr_t.withName("PSID");
+
+       Type.PACL =
+         Type.voidptr_t.withName("PACL");
+
+       Type.PSECURITY_DESCRIPTOR =
+         Type.voidptr_t.withName("PSECURITY_DESCRIPTOR");
+
+       /**
+        * A C integer holding Win32 local memory handle.
+        */
+       Type.HLOCAL =
+         Type.voidptr_t.withName("HLOCAL");
+
+       Type.FILETIME =
+         new SharedAll.Type("FILETIME",
+                  ctypes.StructType("FILETIME", [
+                  { lo: Type.DWORD.implementation },
+                  { hi: Type.DWORD.implementation }]));
+
+       Type.FindData =
+         new SharedAll.Type("FIND_DATA",
+                  ctypes.StructType("FIND_DATA", [
+                    { dwFileAttributes: ctypes.uint32_t },
+                    { ftCreationTime:   Type.FILETIME.implementation },
+                    { ftLastAccessTime: Type.FILETIME.implementation },
+                    { ftLastWriteTime:  Type.FILETIME.implementation },
+                    { nFileSizeHigh:    Type.DWORD.implementation },
+                    { nFileSizeLow:     Type.DWORD.implementation },
+                    { dwReserved0:      Type.DWORD.implementation },
+                    { dwReserved1:      Type.DWORD.implementation },
+                    { cFileName:        ctypes.ArrayType(ctypes.char16_t, Const.MAX_PATH) },
+                    { cAlternateFileName: ctypes.ArrayType(ctypes.char16_t, 14) }
+                      ]));
+
+       Type.FILE_INFORMATION =
+         new SharedAll.Type("FILE_INFORMATION",
+                  ctypes.StructType("FILE_INFORMATION", [
+                    { dwFileAttributes: ctypes.uint32_t },
+                    { ftCreationTime:   Type.FILETIME.implementation },
+                    { ftLastAccessTime: Type.FILETIME.implementation },
+                    { ftLastWriteTime:  Type.FILETIME.implementation },
+                    { dwVolumeSerialNumber: ctypes.uint32_t },
+                    { nFileSizeHigh:    Type.DWORD.implementation },
+                    { nFileSizeLow:     Type.DWORD.implementation },
+                    { nNumberOfLinks:   ctypes.uint32_t },
+                    { nFileIndex: ctypes.uint64_t }
+                   ]));
+
+       Type.SystemTime =
+         new SharedAll.Type("SystemTime",
+                  ctypes.StructType("SystemTime", [
+                  { wYear:      ctypes.int16_t },
+                  { wMonth:     ctypes.int16_t },
+                  { wDayOfWeek: ctypes.int16_t },
+                  { wDay:       ctypes.int16_t },
+                  { wHour:      ctypes.int16_t },
+                  { wMinute:    ctypes.int16_t },
+                  { wSecond:    ctypes.int16_t },
+                  { wMilliSeconds: ctypes.int16_t }
+                  ]));
+
+       // Special case: these functions are used by the
+       // finalizer
+       libc.declareLazy(SysFile, "_CloseHandle",
+                        "CloseHandle", ctypes.winapi_abi,
+                        /*return */ctypes.bool,
+                        /*handle*/ ctypes.voidptr_t);
+
+       SysFile.CloseHandle = function(fd) {
+         if (fd == INVALID_HANDLE) {
+           return true;
+         } else {
+           return fd.dispose(); // Returns the value of |CloseHandle|.
+         }
+       };
+
+       libc.declareLazy(SysFile, "_FindClose",
+                        "FindClose", ctypes.winapi_abi,
+                        /*return */ctypes.bool,
+                        /*handle*/ ctypes.voidptr_t);
+
+       SysFile.FindClose = function(handle) {
+         if (handle == INVALID_HANDLE) {
+           return true;
+         } else {
+           return handle.dispose(); // Returns the value of |FindClose|.
+         }
+       };
+
+       // Declare libc functions as functions of |OS.Win.File|
+
+       libc.declareLazyFFI(SysFile, "CopyFile",
+         "CopyFileW", ctypes.winapi_abi,
+                    /*return*/ Type.zero_or_nothing,
+                    /*sourcePath*/ Type.path,
+                    /*destPath*/   Type.path,
+                    /*bailIfExist*/Type.bool);
+
+       libc.declareLazyFFI(SysFile, "CreateDirectory",
+         "CreateDirectoryW", ctypes.winapi_abi,
+                    /*return*/ Type.zero_or_nothing,
+                    /*name*/   Type.char16_t.in_ptr,
+                    /*security*/Type.SECURITY_ATTRIBUTES.in_ptr);
+
+       libc.declareLazyFFI(SysFile, "CreateFile",
+         "CreateFileW", ctypes.winapi_abi,
+                    /*return*/  Type.file_HANDLE,
+                    /*name*/    Type.path,
+                    /*access*/  Type.DWORD_FLAGS,
+                    /*share*/   Type.DWORD_FLAGS,
+                    /*security*/Type.SECURITY_ATTRIBUTES.in_ptr,
+                    /*creation*/Type.DWORD_FLAGS,
+                    /*flags*/   Type.DWORD_FLAGS,
+                    /*template*/Type.HANDLE);
+
+       libc.declareLazyFFI(SysFile, "DeleteFile",
+         "DeleteFileW", ctypes.winapi_abi,
+                    /*return*/ Type.zero_or_nothing,
+                    /*path*/   Type.path);
+
+       libc.declareLazyFFI(SysFile, "FileTimeToSystemTime",
+         "FileTimeToSystemTime", ctypes.winapi_abi,
+                    /*return*/ Type.zero_or_nothing,
+                    /*filetime*/Type.FILETIME.in_ptr,
+                    /*systime*/ Type.SystemTime.out_ptr);
+
+       libc.declareLazyFFI(SysFile, "SystemTimeToFileTime",
+         "SystemTimeToFileTime", ctypes.winapi_abi,
+                    /*return*/   Type.zero_or_nothing,
+                    /*systime*/  Type.SystemTime.in_ptr,
+                    /*filetime*/ Type.FILETIME.out_ptr);
+
+       libc.declareLazyFFI(SysFile, "FindFirstFile",
+         "FindFirstFileW", ctypes.winapi_abi,
+                    /*return*/ Type.find_HANDLE,
+                    /*pattern*/Type.path,
+                    /*data*/   Type.FindData.out_ptr);
+
+       libc.declareLazyFFI(SysFile, "FindNextFile",
+         "FindNextFileW", ctypes.winapi_abi,
+                    /*return*/ Type.zero_or_nothing,
+                    /*prev*/   Type.find_HANDLE,
+                    /*data*/   Type.FindData.out_ptr);
+
+       libc.declareLazyFFI(SysFile, "FormatMessage",
+         "FormatMessageW", ctypes.winapi_abi,
+                    /*return*/ Type.DWORD,
+                    /*flags*/  Type.DWORD_FLAGS,
+                    /*source*/ Type.void_t.in_ptr,
+                    /*msgid*/  Type.DWORD_FLAGS,
+                    /*langid*/ Type.DWORD_FLAGS,
+                    /*buf*/    Type.out_wstring,
+                    /*size*/   Type.DWORD,
+                    /*Arguments*/Type.void_t.in_ptr
+                   );
+
+       libc.declareLazyFFI(SysFile, "GetCurrentDirectory",
+         "GetCurrentDirectoryW", ctypes.winapi_abi,
+                    /*return*/ Type.zero_or_DWORD,
+                    /*length*/ Type.DWORD,
+                    /*buf*/    Type.out_path
+                   );
+
+       libc.declareLazyFFI(SysFile, "GetFullPathName",
+         "GetFullPathNameW", ctypes.winapi_abi,
+                    /*return*/   Type.zero_or_DWORD,
+                    /*fileName*/ Type.path,
+                    /*length*/   Type.DWORD,
+                    /*buf*/      Type.out_path,
+                    /*filePart*/ Type.DWORD
+                   );
+
+       libc.declareLazyFFI(SysFile, "GetDiskFreeSpaceEx",
+         "GetDiskFreeSpaceExW", ctypes.winapi_abi,
+                    /*return*/ Type.zero_or_nothing,
+                    /*directoryName*/ Type.path,
+                    /*freeBytesForUser*/ Type.uint64_t.out_ptr,
+                    /*totalBytesForUser*/ Type.uint64_t.out_ptr,
+                    /*freeTotalBytesOnDrive*/ Type.uint64_t.out_ptr);
+
+       libc.declareLazyFFI(SysFile, "GetFileInformationByHandle",
+         "GetFileInformationByHandle", ctypes.winapi_abi,
+                    /*return*/ Type.zero_or_nothing,
+                    /*handle*/ Type.HANDLE,
+                    /*info*/   Type.FILE_INFORMATION.out_ptr);
+
+       libc.declareLazyFFI(SysFile, "MoveFileEx",
+         "MoveFileExW", ctypes.winapi_abi,
+                    /*return*/   Type.zero_or_nothing,
+                    /*sourcePath*/ Type.path,
+                    /*destPath*/ Type.path,
+                    /*flags*/    Type.DWORD
+                   );
+
+       libc.declareLazyFFI(SysFile, "ReadFile",
+         "ReadFile", ctypes.winapi_abi,
+                    /*return*/ Type.zero_or_nothing,
+                    /*file*/   Type.HANDLE,
+                    /*buffer*/ Type.voidptr_t,
+                    /*nbytes*/ Type.DWORD,
+                    /*nbytes_read*/Type.DWORD.out_ptr,
+                    /*overlapped*/Type.void_t.inout_ptr // FIXME: Implement?
+         );
+
+       libc.declareLazyFFI(SysFile, "RemoveDirectory",
+         "RemoveDirectoryW", ctypes.winapi_abi,
+                    /*return*/ Type.zero_or_nothing,
+                    /*path*/   Type.path);
+
+       libc.declareLazyFFI(SysFile, "SetCurrentDirectory",
+         "SetCurrentDirectoryW", ctypes.winapi_abi,
+                    /*return*/ Type.zero_or_nothing,
+                    /*path*/   Type.path
+                   );
+
+       libc.declareLazyFFI(SysFile, "SetEndOfFile",
+         "SetEndOfFile", ctypes.winapi_abi,
+                    /*return*/ Type.zero_or_nothing,
+                    /*file*/   Type.HANDLE);
+
+       libc.declareLazyFFI(SysFile, "SetFilePointer",
+         "SetFilePointer", ctypes.winapi_abi,
+                    /*return*/ Type.DWORD,
+                    /*file*/   Type.HANDLE,
+                    /*distlow*/Type.long,
+                    /*disthi*/ Type.long.in_ptr,
+                    /*method*/ Type.DWORD);
+
+       libc.declareLazyFFI(SysFile, "SetFileTime",
+         "SetFileTime",  ctypes.winapi_abi,
+                    /*return*/   Type.zero_or_nothing,
+                    /*file*/     Type.HANDLE,
+                    /*creation*/ Type.FILETIME.in_ptr,
+                    /*access*/   Type.FILETIME.in_ptr,
+                    /*write*/    Type.FILETIME.in_ptr);
+
+
+       libc.declareLazyFFI(SysFile, "WriteFile",
+         "WriteFile", ctypes.winapi_abi,
+                    /*return*/ Type.zero_or_nothing,
+                    /*file*/   Type.HANDLE,
+                    /*buffer*/ Type.voidptr_t,
+                    /*nbytes*/ Type.DWORD,
+                    /*nbytes_wr*/Type.DWORD.out_ptr,
+                    /*overlapped*/Type.void_t.inout_ptr // FIXME: Implement?
+         );
+
+        libc.declareLazyFFI(SysFile, "FlushFileBuffers",
+          "FlushFileBuffers", ctypes.winapi_abi,
+                     /*return*/ Type.zero_or_nothing,
+                     /*file*/   Type.HANDLE);
+
+        libc.declareLazyFFI(SysFile, "GetFileAttributes",
+          "GetFileAttributesW", ctypes.winapi_abi,
+                     /*return*/   Type.DWORD_FLAGS,
+                     /*fileName*/ Type.path);
+
+        libc.declareLazyFFI(SysFile, "SetFileAttributes",
+          "SetFileAttributesW", ctypes.winapi_abi,
+                     /*return*/         Type.zero_or_nothing,
+                     /*fileName*/       Type.path,
+                     /*fileAttributes*/ Type.DWORD_FLAGS);
+
+        advapi32.declareLazyFFI(SysFile, "GetNamedSecurityInfo",
+          "GetNamedSecurityInfoW", ctypes.winapi_abi,
+                     /*return*/       Type.DWORD,
+                     /*objectName*/   Type.path,
+                     /*objectType*/   Type.DWORD,
+                     /*securityInfo*/ Type.DWORD,
+                     /*sidOwner*/     Type.PSID.out_ptr,
+                     /*sidGroup*/     Type.PSID.out_ptr,
+                     /*dacl*/         Type.PACL.out_ptr,
+                     /*sacl*/         Type.PACL.out_ptr,
+                     /*securityDesc*/ Type.PSECURITY_DESCRIPTOR.out_ptr);
+
+        advapi32.declareLazyFFI(SysFile, "SetNamedSecurityInfo",
+          "SetNamedSecurityInfoW", ctypes.winapi_abi,
+                     /*return*/       Type.DWORD,
+                     /*objectName*/   Type.path,
+                     /*objectType*/   Type.DWORD,
+                     /*securityInfo*/ Type.DWORD,
+                     /*sidOwner*/     Type.PSID,
+                     /*sidGroup*/     Type.PSID,
+                     /*dacl*/         Type.PACL,
+                     /*sacl*/         Type.PACL);
+
+        libc.declareLazyFFI(SysFile, "LocalFree",
+          "LocalFree", ctypes.winapi_abi,
+                     /*return*/       Type.HLOCAL,
+                     /*mem*/          Type.HLOCAL);
+     };
+
+     exports.OS.Win = {
+       File: {
+           _init:  init
+       }
+     };
+   })(this);
+}

toolkit/components/osfile/modules/ospath.jsm

@@ -0,0 +1,45 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Handling native paths.
+ *
+ * This module contains a number of functions destined to simplify
+ * working with native paths through a cross-platform API. Functions
+ * of this module will only work with the following assumptions:
+ *
+ * - paths are valid;
+ * - paths are defined with one of the grammars that this module can
+ *   parse (see later);
+ * - all path concatenations go through function |join|.
+ */
+
+"use strict";
+
+if (typeof Components == "undefined") {
+  let Path;
+  if (OS.Constants.Win) {
+    Path = require("resource://gre/modules/osfile/ospath_win.jsm");
+  } else {
+    Path = require("resource://gre/modules/osfile/ospath_unix.jsm");
+  }
+  module.exports = Path;
+} else {
+  let Cu = Components.utils;
+  let Scope = {};
+  Cu.import("resource://gre/modules/osfile/osfile_shared_allthreads.jsm", Scope);
+
+  let Path = {};
+  if (Scope.OS.Constants.Win) {
+    Cu.import("resource://gre/modules/osfile/ospath_win.jsm", Path);
+  } else {
+    Cu.import("resource://gre/modules/osfile/ospath_unix.jsm", Path);
+  }
+
+  this.EXPORTED_SYMBOLS = [];
+  for (let k in Path) {
+    this.EXPORTED_SYMBOLS.push(k);
+    this[k] = Path[k];
+  }
+}

toolkit/components/osfile/modules/ospath_unix.jsm

@@ -0,0 +1,202 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Handling native paths.
+ *
+ * This module contains a number of functions destined to simplify
+ * working with native paths through a cross-platform API. Functions
+ * of this module will only work with the following assumptions:
+ *
+ * - paths are valid;
+ * - paths are defined with one of the grammars that this module can
+ *   parse (see later);
+ * - all path concatenations go through function |join|.
+ */
+
+"use strict";
+
+// Boilerplate used to be able to import this module both from the main
+// thread and from worker threads.
+if (typeof Components != "undefined") {
+  Components.utils.importGlobalProperties(["URL"]);
+  // Global definition of |exports|, to keep everybody happy.
+  // In non-main thread, |exports| is provided by the module
+  // loader.
+  this.exports = {};
+} else if (typeof module == "undefined" || typeof exports == "undefined") {
+  throw new Error("Please load this module using require()");
+}
+
+var EXPORTED_SYMBOLS = [
+  "basename",
+  "dirname",
+  "join",
+  "normalize",
+  "split",
+  "toFileURI",
+  "fromFileURI",
+];
+
+/**
+ * Return the final part of the path.
+ * The final part of the path is everything after the last "/".
+ */
+var basename = function(path) {
+  return path.slice(path.lastIndexOf("/") + 1);
+};
+exports.basename = basename;
+
+/**
+ * Return the directory part of the path.
+ * The directory part of the path is everything before the last
+ * "/". If the last few characters of this part are also "/",
+ * they are ignored.
+ *
+ * If the path contains no directory, return ".".
+ */
+var dirname = function(path) {
+  let index = path.lastIndexOf("/");
+  if (index == -1) {
+    return ".";
+  }
+  while (index >= 0 && path[index] == "/") {
+    --index;
+  }
+  return path.slice(0, index + 1);
+};
+exports.dirname = dirname;
+
+/**
+ * Join path components.
+ * This is the recommended manner of getting the path of a file/subdirectory
+ * in a directory.
+ *
+ * Example: Obtaining $TMP/foo/bar in an OS-independent manner
+ *  var tmpDir = OS.Constants.Path.tmpDir;
+ *  var path = OS.Path.join(tmpDir, "foo", "bar");
+ *
+ * Under Unix, this will return "/tmp/foo/bar".
+ *
+ * Empty components are ignored, i.e. `OS.Path.join("foo", "", "bar)` is the
+ * same as `OS.Path.join("foo", "bar")`.
+ */
+var join = function(...path) {
+  // If there is a path that starts with a "/", eliminate everything before
+  let paths = [];
+  for (let subpath of path) {
+    if (subpath == null) {
+      throw new TypeError("invalid path component");
+    }
+    if (subpath.length == 0) {
+      continue;
+    } else if (subpath[0] == "/") {
+      paths = [subpath];
+    } else {
+      paths.push(subpath);
+    }
+  }
+  return paths.join("/");
+};
+exports.join = join;
+
+/**
+ * Normalize a path by removing any unneeded ".", "..", "//".
+ */
+var normalize = function(path) {
+  let stack = [];
+  let absolute;
+  if (path.length >= 0 && path[0] == "/") {
+    absolute = true;
+  } else {
+    absolute = false;
+  }
+  path.split("/").forEach(function(v) {
+    switch (v) {
+    case "":  case ".":// fallthrough
+      break;
+    case "..":
+      if (stack.length == 0) {
+        if (absolute) {
+          throw new Error("Path is ill-formed: attempting to go past root");
+        } else {
+          stack.push("..");
+        }
+      } else {
+        if (stack[stack.length - 1] == "..") {
+          stack.push("..");
+        } else {
+          stack.pop();
+        }
+      }
+      break;
+    default:
+      stack.push(v);
+    }
+  });
+  let string = stack.join("/");
+  return absolute ? "/" + string : string;
+};
+exports.normalize = normalize;
+
+/**
+ * Return the components of a path.
+ * You should generally apply this function to a normalized path.
+ *
+ * @return {{
+ *   {bool} absolute |true| if the path is absolute, |false| otherwise
+ *   {array} components the string components of the path
+ * }}
+ *
+ * Other implementations may add additional OS-specific informations.
+ */
+var split = function(path) {
+  return {
+    absolute: path.length && path[0] == "/",
+    components: path.split("/")
+  };
+};
+exports.split = split;
+
+/**
+ * Returns the file:// URI file path of the given local file path.
+ */
+// The case of %3b is designed to match Services.io, but fundamentally doesn't matter.
+var toFileURIExtraEncodings = {';': '%3b', '?': '%3F', '#': '%23'};
+var toFileURI = function toFileURI(path) {
+  // Per https://url.spec.whatwg.org we should not encode [] in the path
+  let dontNeedEscaping = {'%5B': '[', '%5D': ']'};
+  let uri = encodeURI(this.normalize(path)).replace(/%(5B|5D)/gi,
+    match => dontNeedEscaping[match]);
+
+  // add a prefix, and encodeURI doesn't escape a few characters that we do
+  // want to escape, so fix that up
+  let prefix = "file://";
+  uri = prefix + uri.replace(/[;?#]/g, match => toFileURIExtraEncodings[match]);
+
+  return uri;
+};
+exports.toFileURI = toFileURI;
+
+/**
+ * Returns the local file path from a given file URI.
+ */
+var fromFileURI = function fromFileURI(uri) {
+  let url = new URL(uri);
+  if (url.protocol != 'file:') {
+    throw new Error("fromFileURI expects a file URI");
+  }
+  let path = this.normalize(decodeURIComponent(url.pathname));
+  return path;
+};
+exports.fromFileURI = fromFileURI;
+
+
+//////////// Boilerplate
+if (typeof Components != "undefined") {
+  this.EXPORTED_SYMBOLS = EXPORTED_SYMBOLS;
+  for (let symbol of EXPORTED_SYMBOLS) {
+    this[symbol] = exports[symbol];
+  }
+}

toolkit/components/osfile/modules/ospath_win.jsm

@@ -0,0 +1,373 @@
+/**
+ * Handling native paths.
+ *
+ * This module contains a number of functions destined to simplify
+ * working with native paths through a cross-platform API. Functions
+ * of this module will only work with the following assumptions:
+ *
+ * - paths are valid;
+ * - paths are defined with one of the grammars that this module can
+ *   parse (see later);
+ * - all path concatenations go through function |join|.
+ *
+ * Limitations of this implementation.
+ *
+ * Windows supports 6 distinct grammars for paths. For the moment, this
+ * implementation supports the following subset:
+ *
+ * - drivename:backslash-separated components
+ * - backslash-separated components
+ * - \\drivename\ followed by backslash-separated components
+ *
+ * Additionally, |normalize| can convert a path containing slash-
+ * separated components to a path containing backslash-separated
+ * components.
+ */
+
+"use strict";
+
+// Boilerplate used to be able to import this module both from the main
+// thread and from worker threads.
+if (typeof Components != "undefined") {
+  Components.utils.importGlobalProperties(["URL"]);
+  // Global definition of |exports|, to keep everybody happy.
+  // In non-main thread, |exports| is provided by the module
+  // loader.
+  this.exports = {};
+} else if (typeof module == "undefined" || typeof exports == "undefined") {
+  throw new Error("Please load this module using require()");
+}
+
+var EXPORTED_SYMBOLS = [
+  "basename",
+  "dirname",
+  "join",
+  "normalize",
+  "split",
+  "winGetDrive",
+  "winIsAbsolute",
+  "toFileURI",
+  "fromFileURI",
+];
+
+/**
+ * Return the final part of the path.
+ * The final part of the path is everything after the last "\\".
+ */
+var basename = function(path) {
+  if (path.startsWith("\\\\")) {
+    // UNC-style path
+    let index = path.lastIndexOf("\\");
+    if (index != 1) {
+      return path.slice(index + 1);
+    }
+    return ""; // Degenerate case
+  }
+  return path.slice(Math.max(path.lastIndexOf("\\"),
+                             path.lastIndexOf(":")) + 1);
+};
+exports.basename = basename;
+
+/**
+ * Return the directory part of the path.
+ *
+ * If the path contains no directory, return the drive letter,
+ * or "." if the path contains no drive letter or if option
+ * |winNoDrive| is set.
+ *
+ * Otherwise, return everything before the last backslash,
+ * including the drive/server name.
+ *
+ *
+ * @param {string} path The path.
+ * @param {*=} options Platform-specific options controlling the behavior
+ * of this function. This implementation supports the following options:
+ *  - |winNoDrive| If |true|, also remove the letter from the path name.
+ */
+var dirname = function(path, options) {
+  let noDrive = (options && options.winNoDrive);
+
+  // Find the last occurrence of "\\"
+  let index = path.lastIndexOf("\\");
+  if (index == -1) {
+    // If there is no directory component...
+    if (!noDrive) {
+      // Return the drive path if possible, falling back to "."
+      return this.winGetDrive(path) || ".";
+    } else {
+      // Or just "."
+      return ".";
+    }
+  }
+
+  if (index == 1 && path.charAt(0) == "\\") {
+    // The path is reduced to a UNC drive
+    if (noDrive) {
+      return ".";
+    } else {
+      return path;
+    }
+  }
+
+  // Ignore any occurrence of "\\: immediately before that one
+  while (index >= 0 && path[index] == "\\") {
+    --index;
+  }
+
+  // Compute what is left, removing the drive name if necessary
+  let start;
+  if (noDrive) {
+    start = (this.winGetDrive(path) || "").length;
+  } else {
+    start = 0;
+  }
+  return path.slice(start, index + 1);
+};
+exports.dirname = dirname;
+
+/**
+ * Join path components.
+ * This is the recommended manner of getting the path of a file/subdirectory
+ * in a directory.
+ *
+ * Example: Obtaining $TMP/foo/bar in an OS-independent manner
+ *  var tmpDir = OS.Constants.Path.tmpDir;
+ *  var path = OS.Path.join(tmpDir, "foo", "bar");
+ *
+ * Under Windows, this will return "$TMP\foo\bar".
+ *
+ * Empty components are ignored, i.e. `OS.Path.join("foo", "", "bar)` is the
+ * same as `OS.Path.join("foo", "bar")`.
+ */
+var join = function(...path) {
+  let paths = [];
+  let root;
+  let absolute = false;
+  for (let subpath of path) {
+    if (subpath == null) {
+      throw new TypeError("invalid path component");
+    }
+    if (subpath == "") {
+      continue;
+    }
+    let drive = this.winGetDrive(subpath);
+    if (drive) {
+      root = drive;
+      let component = trimBackslashes(subpath.slice(drive.length));
+      if (component) {
+        paths = [component];
+      } else {
+        paths = [];
+      }
+      absolute = true;
+    } else if (this.winIsAbsolute(subpath)) {
+      paths = [trimBackslashes(subpath)];
+      absolute = true;
+    } else {
+      paths.push(trimBackslashes(subpath));
+    }
+  }
+  let result = "";
+  if (root) {
+    result += root;
+  }
+  if (absolute) {
+    result += "\\";
+  }
+  result += paths.join("\\");
+  return result;
+};
+exports.join = join;
+
+/**
+ * Return the drive name of a path, or |null| if the path does
+ * not contain a drive name.
+ *
+ * Drive name appear either as "DriveName:..." (the return drive
+ * name includes the ":") or "\\\\DriveName..." (the returned drive name
+ * includes "\\\\").
+ */
+var winGetDrive = function(path) {
+  if (path == null) {
+    throw new TypeError("path is invalid");
+  }
+
+  if (path.startsWith("\\\\")) {
+    // UNC path
+    if (path.length == 2) {
+      return null;
+    }
+    let index = path.indexOf("\\", 2);
+    if (index == -1) {
+      return path;
+    }
+    return path.slice(0, index);
+  }
+  // Non-UNC path
+  let index = path.indexOf(":");
+  if (index <= 0) return null;
+  return path.slice(0, index + 1);
+};
+exports.winGetDrive = winGetDrive;
+
+/**
+ * Return |true| if the path is absolute, |false| otherwise.
+ *
+ * We consider that a path is absolute if it starts with "\\"
+ * or "driveletter:\\".
+ */
+var winIsAbsolute = function(path) {
+  let index = path.indexOf(":");
+  return path.length > index + 1 && path[index + 1] == "\\";
+};
+exports.winIsAbsolute = winIsAbsolute;
+
+/**
+ * Normalize a path by removing any unneeded ".", "..", "\\".
+ * Also convert any "/" to a "\\".
+ */
+var normalize = function(path) {
+  let stack = [];
+
+  if (!path.startsWith("\\\\")) {
+    // Normalize "/" to "\\"
+    path = path.replace(/\//g, "\\");
+  }
+
+  // Remove the drive (we will put it back at the end)
+  let root = this.winGetDrive(path);
+  if (root) {
+    path = path.slice(root.length);
+  }
+
+  // Remember whether we need to restore a leading "\\" or drive name.
+  let absolute = this.winIsAbsolute(path);
+
+  // And now, fill |stack| from the components,
+  // popping whenever there is a ".."
+  path.split("\\").forEach(function loop(v) {
+    switch (v) {
+    case "":  case ".": // Ignore
+      break;
+    case "..":
+      if (stack.length == 0) {
+        if (absolute) {
+          throw new Error("Path is ill-formed: attempting to go past root");
+        } else {
+         stack.push("..");
+        }
+      } else {
+        if (stack[stack.length - 1] == "..") {
+          stack.push("..");
+        } else {
+          stack.pop();
+        }
+      }
+      break;
+    default:
+      stack.push(v);
+    }
+  });
+
+  // Put everything back together
+  let result = stack.join("\\");
+  if (absolute || root) {
+    result = "\\" + result;
+  }
+  if (root) {
+    result = root + result;
+  }
+  return result;
+};
+exports.normalize = normalize;
+
+/**
+ * Return the components of a path.
+ * You should generally apply this function to a normalized path.
+ *
+ * @return {{
+ *   {bool} absolute |true| if the path is absolute, |false| otherwise
+ *   {array} components the string components of the path
+ *   {string?} winDrive the drive or server for this path
+ * }}
+ *
+ * Other implementations may add additional OS-specific informations.
+ */
+var split = function(path) {
+  return {
+    absolute: this.winIsAbsolute(path),
+    winDrive: this.winGetDrive(path),
+    components: path.split("\\")
+  };
+};
+exports.split = split;
+
+/**
+ * Return the file:// URI file path of the given local file path.
+ */
+// The case of %3b is designed to match Services.io, but fundamentally doesn't matter.
+var toFileURIExtraEncodings = {';': '%3b', '?': '%3F', '#': '%23'};
+var toFileURI = function toFileURI(path) {
+  // URI-escape forward slashes and convert backward slashes to forward
+  path = this.normalize(path).replace(/[\\\/]/g, m => (m=='\\')? '/' : '%2F');
+  // Per https://url.spec.whatwg.org we should not encode [] in the path
+  let dontNeedEscaping = {'%5B': '[', '%5D': ']'};
+  let uri = encodeURI(path).replace(/%(5B|5D)/gi,
+    match => dontNeedEscaping[match]);
+
+  // add a prefix, and encodeURI doesn't escape a few characters that we do
+  // want to escape, so fix that up
+  let prefix = "file:///";
+  uri = prefix + uri.replace(/[;?#]/g, match => toFileURIExtraEncodings[match]);
+
+  // turn e.g., file:///C: into file:///C:/
+  if (uri.charAt(uri.length - 1) === ':') {
+    uri += "/"
+  }
+
+  return uri;
+};
+exports.toFileURI = toFileURI;
+
+/**
+ * Returns the local file path from a given file URI.
+ */
+var fromFileURI = function fromFileURI(uri) {
+  let url = new URL(uri);
+  if (url.protocol != 'file:') {
+    throw new Error("fromFileURI expects a file URI");
+  }
+
+  // strip leading slash, since Windows paths don't start with one
+  uri = url.pathname.substr(1);
+
+  let path = decodeURI(uri);
+  // decode a few characters where URL's parsing is overzealous
+  path = path.replace(/%(3b|3f|23)/gi,
+        match => decodeURIComponent(match));
+  path = this.normalize(path);
+
+  // this.normalize() does not remove the trailing slash if the path
+  // component is a drive letter. eg. 'C:\'' will not get normalized.
+  if (path.endsWith(":\\")) {
+    path = path.substr(0, path.length - 1);
+  }
+  return this.normalize(path);
+};
+exports.fromFileURI = fromFileURI;
+
+/**
+* Utility function: Remove any leading/trailing backslashes
+* from a string.
+*/
+var trimBackslashes = function trimBackslashes(string) {
+  return string.replace(/^\\+|\\+$/g,'');
+};
+
+//////////// Boilerplate
+if (typeof Components != "undefined") {
+  this.EXPORTED_SYMBOLS = EXPORTED_SYMBOLS;
+  for (let symbol of EXPORTED_SYMBOLS) {
+    this[symbol] = exports[symbol];
+  }
+}