Dactyloidae iOS initial commit

mobile/ios/Client/Extensions/UIPasteboardExtensions.swift

@@ -0,0 +1,63 @@
+/* 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/. */
+
+import Deferred
+import Foundation
+import MobileCoreServices
+import Shared
+import UIKit
+
+extension UIPasteboard {
+    func addImageWithData(_ data: Data, forURL url: URL) {
+        let isGIF = UIImage.dataIsGIF(data)
+
+        // Setting pasteboard.items allows us to set multiple representations for the same item.
+        items = [[
+            kUTTypeURL as String: url,
+            imageTypeKey(isGIF): data
+        ]]
+    }
+
+    fileprivate func imageTypeKey(_ isGIF: Bool) -> String {
+        return (isGIF ? kUTTypeGIF : kUTTypePNG) as String
+    }
+
+    private var syncURL: URL? {
+        if let string = UIPasteboard.general.string,
+            let url = URL(string: string), url.isWebPage() {
+            return url
+        } else {
+            return nil
+        }
+    }
+
+    /// Preferred method to get strings out of the clipboard.
+    /// When iCloud pasteboards are enabled, the usually fast, synchronous calls
+    /// become slow and synchronous causing very slow start up times.
+    func asyncString() -> Deferred<Maybe<String?>> {
+        return fetchAsync() {
+            return UIPasteboard.general.string
+        }
+    }
+
+    /// Preferred method to get URLs out of the clipboard.
+    /// We use Deferred<Maybe<T?>> to fit in to the rest of the Deferred<Maybe> tools
+    /// we already use; but use optionals instead of errorTypes, because not having a URL
+    /// on the clipboard isn't an error.
+    func asyncURL() -> Deferred<Maybe<URL?>> {
+        return fetchAsync() {
+            return self.syncURL
+        }
+    }
+
+    // Converts the potentially long running synchronous operation into an asynchronous one.
+    private func fetchAsync<T>(getter: @escaping () -> T) -> Deferred<Maybe<T>> {
+        let deferred = Deferred<Maybe<T>>()
+        DispatchQueue.global().async {
+            let value = getter()
+            deferred.fill(Maybe(success: value))
+        }
+        return deferred
+    }
+}