Dactyloidae iOS initial commit

mobile/ios/Shared/Extensions/NSFileManagerExtensions.swift

@@ -0,0 +1,112 @@
+/* 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/. */
+
+/* Created and contributed by Nikolai Ruhe and rewritten in Swift.
+ * https://github.com/NikolaiRuhe/NRFoundation */
+
+import Foundation
+
+public let NSFileManagerExtensionsDomain = "org.mozilla.NSFileManagerExtensions"
+
+public enum NSFileManagerExtensionsErrorCodes: Int {
+    case enumeratorFailure = 0
+    case enumeratorElementNotURL = 1
+    case errorEnumeratingDirectory = 2
+}
+
+public extension FileManager {
+
+    private func directoryEnumeratorForURL(_ url: URL) throws -> FileManager.DirectoryEnumerator {
+        let prefetchedProperties = [
+            URLResourceKey.isRegularFileKey,
+            URLResourceKey.fileAllocatedSizeKey,
+            URLResourceKey.totalFileAllocatedSizeKey
+        ]
+
+        // If we run into an issue getting an enumerator for the given URL, capture the error and bail out later.
+        var enumeratorError: NSError?
+        let errorHandler: (URL, Error) -> Bool = { _, error in
+            enumeratorError = error as NSError
+            return false
+        }
+
+        guard let directoryEnumerator = FileManager.default.enumerator(at: url,
+            includingPropertiesForKeys: prefetchedProperties,
+            options: [],
+            errorHandler: errorHandler) else {
+            throw errorWithCode(.enumeratorFailure)
+        }
+
+        // Bail out if we encountered an issue getting the enumerator.
+        if let _ = enumeratorError {
+            throw errorWithCode(.errorEnumeratingDirectory, underlyingError: enumeratorError)
+        }
+
+        return directoryEnumerator
+    }
+
+    private func sizeForItemURL(_ url: Any, withPrefix prefix: String) throws -> Int64 {
+        guard let itemURL = url as? URL else {
+            throw errorWithCode(.enumeratorElementNotURL)
+        }
+
+        // Skip files that are not regular and don't match our prefix
+        guard itemURL.isRegularFile && itemURL.lastComponentIsPrefixedBy(prefix) else {
+            return 0
+        }
+
+        return itemURL.allocatedFileSize()
+    }
+
+    func allocatedSizeOfDirectoryAtURL(_ url: URL, forFilesPrefixedWith prefix: String, isLargerThanBytes threshold: Int64) throws -> Bool {
+        let directoryEnumerator = try directoryEnumeratorForURL(url)
+        var acc: Int64 = 0
+        for item in directoryEnumerator {
+            acc += try sizeForItemURL(item as AnyObject, withPrefix: prefix)
+            if acc > threshold {
+                return true
+            }
+        }
+        return false
+    }
+
+    /**
+     Returns the precise size of the given directory on disk.
+
+     - parameter url:    Directory URL
+     - parameter prefix: Prefix of files to check for size
+
+     - throws: Error reading/operating on disk.
+     */
+    func getAllocatedSizeOfDirectoryAtURL(_ url: URL, forFilesPrefixedWith prefix: String) throws -> Int64 {
+        let directoryEnumerator = try directoryEnumeratorForURL(url)
+        return try directoryEnumerator.reduce(0) {
+            let size = try sizeForItemURL($1 as AnyObject, withPrefix: prefix)
+            return $0 + size
+        }
+    }
+
+    func contentsOfDirectoryAtPath(_ path: String, withFilenamePrefix prefix: String) throws -> [String] {
+        return try FileManager.default.contentsOfDirectory(atPath: path)
+            .filter { $0.hasPrefix("\(prefix).") }
+            .sorted { $0 < $1 }
+    }
+
+    func removeItemInDirectory(_ directory: String, named: String) throws {
+        let file = URL(fileURLWithPath: directory).appendingPathComponent(named).path
+        try self.removeItem(atPath: file)
+    }
+
+    private func errorWithCode(_ code: NSFileManagerExtensionsErrorCodes, underlyingError error: NSError? = nil) -> NSError {
+        var userInfo = [String: AnyObject]()
+        if let _ = error {
+            userInfo[NSUnderlyingErrorKey] = error
+        }
+
+        return NSError(
+            domain: NSFileManagerExtensionsDomain,
+            code: code.rawValue,
+            userInfo: userInfo)
+    }
+}