Bug 1096804 - Add a new asynchronous callback interface for Windows taskbar thumbnail and preview image requests. r=roc

widget/nsITaskbarPreviewController.idl

@@ -11,6 +11,18 @@ interface nsIDocShell;
 interface nsITaskbarPreview;
 interface nsITaskbarPreviewButton;
 
+/**
+ * nsITaskbarPreviewCallback
+ *
+ * Provides an interface for async image result callbacks. See
+ * nsITaskbarPreviewController request apis below.
+ */
+[scriptable, function, uuid(f3744696-320d-4804-9c27-6a84c29acaa6)]
+interface nsITaskbarPreviewCallback : nsISupports
+{
+  void done(in nsISupports aCanvas, in boolean aDrawBorder);
+};
+
 /**
  * nsITaskbarPreviewController
  *
@@ -20,7 +32,7 @@ interface nsITaskbarPreviewButton;
  * the interface the controller is attached to, only certain methods/attributes
  * are required to be implemented.
  */
-[scriptable, uuid(4FC0AFBB-3E22-4FBA-AC21-953350AF0411)]
+[scriptable, uuid(8b427646-e446-4941-ae0b-c1122a173a68)]
 interface nsITaskbarPreviewController : nsISupports
 {
   /**
@@ -42,31 +54,40 @@ interface nsITaskbarPreviewController : nsISupports
    */
   readonly attribute float thumbnailAspectRatio;
 
-  /**
-   * Invoked by nsITaskbarPreview when it needs to render the preview. The
-   * context is attached to a surface with the controller's width and height
-   * which are obtained immediately before the call.
-   *
-   * Note that the context is not attached to a canvas element.
-   *
-   * @param ctx Canvas drawing context
-   */
+  [deprecated]
   boolean drawPreview(in nsISupports ctx);
 
+  [deprecated]
+  boolean drawThumbnail(in nsISupports ctx, in unsigned long width, in unsigned long height);
+
   /**
-   * Invoked by the taskbar preview when it needs to draw the thumbnail in the
-   * taskbar's application preview window.
+   * Invoked by nsITaskbarPreview when it needs to render the preview.
+   *
+   * @param aCallback Async callback the controller should invoke once
+   * the thumbnail is rendered. aCallback receives as its only parameter
+   * a canvas containing the preview image.
+   */
+  void requestPreview(in nsITaskbarPreviewCallback aCallback);
+
+  /**
+   * An asynchronous version of drawPreview and drawThumbnail apis
+   * implemented in nsITaskbarPreviewController.
    *
    * Note: it is guaranteed that width/height == thumbnailAspectRatio
    * (modulo rounding errors)
    *
    * Also note that the context is not attached to a canvas element.
    *
-   * @param ctx Canvas drawing context
-   * @param width The width of the surface backing the drawing context
-   * @param height The height of the surface backing the drawing context
+   * @param aCallback Async callback the controller should invoke once
+   * the thumbnail is rendered. aCallback receives as its only parameter
+   * a canvas containing the thumbnail image. Canvas dimensions should
+   * match the requested width or height otherwise setting the thumbnail
+   * will fail.
+   * @param width The width of the requested thumbnail
+   * @param height The height of the requested thumbnail
    */
-  boolean drawThumbnail(in nsISupports ctx, in unsigned long width, in unsigned long height);
+  void requestThumbnail(in nsITaskbarPreviewCallback aCallback,
+                        in unsigned long width, in unsigned long height);
 
   /**
    * Invoked when the user presses the close button on the tab preview.
@@ -89,4 +110,3 @@ interface nsITaskbarPreviewController : nsISupports
    */
   void onClick(in nsITaskbarPreviewButton button);
 };
-

widget/nsWidgetsCID.h

@@ -13,7 +13,6 @@
 { 0x2d96b3d1, 0xc051, 0x11d1, \
     {0xa8, 0x27, 0x00, 0x40, 0x95, 0x9a, 0x28, 0xc9} }
 
-
 /* BA7DE611-6088-11d3-A83E-00105A183419 */
 #define NS_POPUP_CID \
 { 0xba7de611, 0x6088, 0x11d3,  \
@@ -44,6 +43,11 @@
  { 0x2d96b3e0, 0xc051, 0x11d1, \
     {0xa8, 0x27, 0x00, 0x40, 0x95, 0x9a, 0x28, 0xc9} }
 
+/* 9A0CB62B-D638-4FAF-9588-AE96F5E29093 */
+#define NS_TASKBARPREVIEWCALLBACK_CID \
+  { 0x9a0cb62b, 0xd638, 0x4faf, \
+    {0x95, 0x88, 0xae, 0x96, 0xf5, 0xe2, 0x90, 0x93} }
+
 /* XXX the following CID's are not in order. This needs
    to be fixed. */
 

widget/windows/nsWidgetFactory.cpp

@@ -119,6 +119,7 @@ NS_GENERIC_FACTORY_CONSTRUCTOR(nsTransferable)
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsHTMLFormatConverter)
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsDragService)
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsBidiKeyboard)
+NS_GENERIC_FACTORY_CONSTRUCTOR(TaskbarPreviewCallback)
 #ifdef NS_PRINTING
 NS_GENERIC_FACTORY_CONSTRUCTOR_INIT(nsPrintOptionsWin, Init)
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsPrinterEnumeratorWin)
@@ -156,6 +157,7 @@ NS_DEFINE_NAMED_CID(NS_WIN_JUMPLISTSHORTCUT_CID);
 NS_DEFINE_NAMED_CID(NS_WINDOWS_UIUTILS_CID);
 NS_DEFINE_NAMED_CID(NS_DRAGSERVICE_CID);
 NS_DEFINE_NAMED_CID(NS_BIDIKEYBOARD_CID);
+NS_DEFINE_NAMED_CID(NS_TASKBARPREVIEWCALLBACK_CID);
 #ifdef NS_PRINTING
 NS_DEFINE_NAMED_CID(NS_PRINTSETTINGSSERVICE_CID);
 NS_DEFINE_NAMED_CID(NS_PRINTER_ENUMERATOR_CID);
@@ -189,6 +191,7 @@ static const mozilla::Module::CIDEntry kWidgetCIDs[] = {
   { &kNS_WINDOWS_UIUTILS_CID, false, nullptr, WindowsUIUtilsConstructor },
   { &kNS_DRAGSERVICE_CID, false, nullptr, nsDragServiceConstructor, Module::MAIN_PROCESS_ONLY },
   { &kNS_BIDIKEYBOARD_CID, false, nullptr, nsBidiKeyboardConstructor },
+  { &kNS_TASKBARPREVIEWCALLBACK_CID, false, nullptr, TaskbarPreviewCallbackConstructor },
 #ifdef NS_PRINTING
   { &kNS_PRINTSETTINGSSERVICE_CID, false, nullptr, nsPrintOptionsWinConstructor },
   { &kNS_PRINTER_ENUMERATOR_CID, false, nullptr, nsPrinterEnumeratorWinConstructor },
@@ -222,6 +225,7 @@ static const mozilla::Module::ContractIDEntry kWidgetContracts[] = {
   { "@mozilla.org/windows-ui-utils;1", &kNS_WINDOWS_UIUTILS_CID },
   { "@mozilla.org/widget/dragservice;1", &kNS_DRAGSERVICE_CID, Module::MAIN_PROCESS_ONLY },
   { "@mozilla.org/widget/bidikeyboard;1", &kNS_BIDIKEYBOARD_CID },
+  { "@mozilla.org/widget/taskbar-preview-callback;1", &kNS_TASKBARPREVIEWCALLBACK_CID },
 #ifdef NS_PRINTING
   { "@mozilla.org/gfx/printsettings-service;1", &kNS_PRINTSETTINGSSERVICE_CID },
   { "@mozilla.org/gfx/printerenumerator;1", &kNS_PRINTER_ENUMERATOR_CID },