pt 1 in reviving the android build (copied from pm 28a1, wish me luck)

mobile/android/modules/AndroidLog.jsm

@@ -0,0 +1,92 @@
+/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
+ * 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/. */
+"use strict";
+
+/**
+ * Native Android logging for JavaScript.  Lets you specify a priority and tag
+ * in addition to the message being logged.  Resembles the android.util.Log API
+ * <http://developer.android.com/reference/android/util/Log.html>.
+ *
+ * // Import it as a JSM:
+ * let Log = Cu.import("resource://gre/modules/AndroidLog.jsm", {}).AndroidLog;
+ *
+ * // Or require it in a chrome worker:
+ * importScripts("resource://gre/modules/workers/require.js");
+ * let Log = require("resource://gre/modules/AndroidLog.jsm");
+ *
+ * // Use Log.i, Log.v, Log.d, Log.w, and Log.e to log verbose, debug, info,
+ * // warning, and error messages, respectively.
+ * Log.v("MyModule", "This is a verbose message.");
+ * Log.d("MyModule", "This is a debug message.");
+ * Log.i("MyModule", "This is an info message.");
+ * Log.w("MyModule", "This is a warning message.");
+ * Log.e("MyModule", "This is an error message.");
+ *
+ * // Bind a function with a tag to replace a bespoke dump/log/debug function:
+ * let debug = Log.d.bind(null, "MyModule");
+ * debug("This is a debug message.");
+ * // Outputs "D/GeckoMyModule(#####): This is a debug message."
+ *
+ * // Or "bind" the module object to a tag to automatically tag messages:
+ * Log = Log.bind("MyModule");
+ * Log.d("This is a debug message.");
+ * // Outputs "D/GeckoMyModule(#####): This is a debug message."
+ *
+ * Note: the module automatically prepends "Gecko" to the tag you specify,
+ * since all tags used by Fennec code should start with that string; and it
+ * truncates tags longer than MAX_TAG_LENGTH characters (not including "Gecko").
+ */
+
+if (typeof Components != "undefined") {
+  // Specify exported symbols for JSM module loader.
+  this.EXPORTED_SYMBOLS = ["AndroidLog"];
+  Components.utils.import("resource://gre/modules/ctypes.jsm");
+}
+
+// From <https://android.googlesource.com/platform/system/core/+/master/include/android/log.h>.
+const ANDROID_LOG_VERBOSE = 2;
+const ANDROID_LOG_DEBUG = 3;
+const ANDROID_LOG_INFO = 4;
+const ANDROID_LOG_WARN = 5;
+const ANDROID_LOG_ERROR = 6;
+
+// android.util.Log.isLoggable throws IllegalArgumentException if a tag length
+// exceeds 23 characters, and we prepend five characters ("Gecko") to every tag,
+// so we truncate tags exceeding 18 characters (although __android_log_write
+// itself and other android.util.Log methods don't seem to mind longer tags).
+const MAX_TAG_LENGTH = 18;
+
+var liblog = ctypes.open("liblog.so"); // /system/lib/liblog.so
+var __android_log_write = liblog.declare("__android_log_write",
+                                         ctypes.default_abi,
+                                         ctypes.int, // return value: num bytes logged
+                                         ctypes.int, // priority (ANDROID_LOG_* constant)
+                                         ctypes.char.ptr, // tag
+                                         ctypes.char.ptr); // message
+
+var AndroidLog = {
+  MAX_TAG_LENGTH: MAX_TAG_LENGTH,
+  v: (tag, msg) => __android_log_write(ANDROID_LOG_VERBOSE, "Gecko" + tag.substring(0, MAX_TAG_LENGTH), msg),
+  d: (tag, msg) => __android_log_write(ANDROID_LOG_DEBUG, "Gecko" + tag.substring(0, MAX_TAG_LENGTH), msg),
+  i: (tag, msg) => __android_log_write(ANDROID_LOG_INFO, "Gecko" + tag.substring(0, MAX_TAG_LENGTH), msg),
+  w: (tag, msg) => __android_log_write(ANDROID_LOG_WARN, "Gecko" + tag.substring(0, MAX_TAG_LENGTH), msg),
+  e: (tag, msg) => __android_log_write(ANDROID_LOG_ERROR, "Gecko" + tag.substring(0, MAX_TAG_LENGTH), msg),
+
+  bind: function(tag) {
+    return {
+      MAX_TAG_LENGTH: MAX_TAG_LENGTH,
+      v: AndroidLog.v.bind(null, tag),
+      d: AndroidLog.d.bind(null, tag),
+      i: AndroidLog.i.bind(null, tag),
+      w: AndroidLog.w.bind(null, tag),
+      e: AndroidLog.e.bind(null, tag),
+    };
+  },
+};
+
+if (typeof Components == "undefined") {
+  // Specify exported symbols for require.js module loader.
+  module.exports = AndroidLog;
+}