Bug 1500206 - In macOS clipboard code fallback to native clipboard for images . r=robwu,mixedpuppy
authorTom Schuster <evilpies@gmail.com>
Mon, 22 Oct 2018 14:39:09 +0000
changeset 442325 2e5b99d12a6daf88e4fffa8f80efb7b874f18379
parent 442324 76763ce5587582f94bcdebd9efb3ce6f625085ea
child 442326 d1e4e5029ffb1e38b6328b8c9d422edfb4603107
push id34904
push userarchaeopteryx@coole-files.de
push dateMon, 22 Oct 2018 17:25:25 +0000
treeherdermozilla-central@af3fd0a2c2e6 [default view] [failures only]
perfherder[talos] [build metrics] [platform microbench] (compared to previous push)
reviewersrobwu, mixedpuppy
bugs1500206
milestone64.0a1
first release with
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
last release without
nightly linux32
nightly linux64
nightly mac
nightly win32
nightly win64
Bug 1500206 - In macOS clipboard code fallback to native clipboard for images . r=robwu,mixedpuppy Differential Revision: https://phabricator.services.mozilla.com/D9132
toolkit/components/extensions/parent/ext-clipboard.js
--- a/toolkit/components/extensions/parent/ext-clipboard.js
+++ b/toolkit/components/extensions/parent/ext-clipboard.js
@@ -11,20 +11,19 @@ const Transferable = Components.Construc
 this.clipboard = class extends ExtensionAPI {
   getAPI(context) {
     return {
       clipboard: {
         async setImageData(imageData, imageType) {
           if (AppConstants.platform == "android") {
             return Promise.reject({message: "Writing images to the clipboard is not supported on Android"});
           }
-          let mimeType = `image/${imageType}`;
           let img;
           try {
-            img = imgTools.decodeImageFromArrayBuffer(imageData, mimeType);
+            img = imgTools.decodeImageFromArrayBuffer(imageData, `image/${imageType}`);
           } catch (e) {
             return Promise.reject({message: `Data is not a valid ${imageType} image`});
           }
 
           // Other applications can only access the copied image once the data
           // is exported via the platform-specific clipboard APIs:
           // nsClipboard::SelectionGetEvent (widget/gtk/nsClipboard.cpp)
           // nsClipboard::PasteDictFromTransferable (widget/cocoa/nsClipboard.mm)
@@ -33,42 +32,37 @@ this.clipboard = class extends Extension
           // The common protocol for exporting a nsITransferable as an image is:
           // - Use nsITransferable::GetTransferData to fetch the stored data.
           // - QI imgIContainer on the pointer.
           // - Convert the image to the native clipboard format.
           //
           // Below we create a nsITransferable in the above format.
           let transferable = new Transferable();
           transferable.init(null);
-          transferable.addDataFlavor(mimeType);
+          const kNativeImageMime = "application/x-moz-nativeimage";
+          transferable.addDataFlavor(kNativeImageMime);
 
           // Internal consumers expect the image data to be stored as a
           // nsIInputStream. On Linux and Windows, pasted data is directly
           // retrieved from the system's native clipboard, and made available
           // as a nsIInputStream.
           //
           // On macOS, nsClipboard::GetNativeClipboardData (nsClipboard.mm) uses
           // a cached copy of nsITransferable if available, e.g. when the copy
-          // was initiated by the same browser instance. Consequently, the
-          // transferable still holds a imgIContainer pointer
-          // instead of a nsIInputStream, and logic that assumes the data to be
-          // a nsIInputStream instance fails.
-          // For example HTMLEditor::InsertObject (HTMLEditorDataTransfer.cpp)
-          // and DataTransferItem::FillInExternalData (DataTransferItem.cpp).
-          //
-          // As a work-around, we force nsClipboard::GetNativeClipboardData to
-          // ignore the cached image data, by passing zero as the length
-          // parameter to transferable.setTransferData. When the length is zero,
-          // nsITransferable::GetTransferData will return NS_ERROR_FAILURE and
-          // conveniently nsClipboard::GetNativeClipboardData will then fall
-          // back to retrieving the data directly from the system's clipboard.
-          //
-          // Note that the length itself is not really used if the data is not
-          // a string type, so the actual value does not matter.
-          transferable.setTransferData(mimeType, img, 0);
+          // was initiated by the same browser instance. To make sure that a
+          // nsIInputStream is returned instead of the cached imgIContainer,
+          // the image is exported as as `kNativeImageMime`. Data associated
+          // with this type is converted to a platform-specific image format
+          // when written to the clipboard. The type is not used when images
+          // are read from the clipboard (on all platforms, not just macOS).
+          // This forces nsClipboard::GetNativeClipboardData to fall back to
+          // the native clipboard, and return the image as a nsITransferable.
+
+          // The length should not be zero. (Bug 1493292)
+          transferable.setTransferData(kNativeImageMime, img, 1);
 
           Services.clipboard.setData(
             transferable, null, Services.clipboard.kGlobalClipboard);
         },
       },
     };
   }
 };