Bug 792199. Only decode visible images immediately when switching to a tab. r=joe

This creates a new method 'StartDecoding' which does a RequestDecode and some
decoding of the image.

--HG--
extra : rebase_source : 89c1c2f40e3dfb6e025939ebf3257f81ce429501

content/base/src/nsDocument.cpp

@@ -8391,7 +8391,7 @@ nsDocument::AddImage(imgIRequest* aImage)
   if (oldCount == 0 && mLockingImages) {
     rv = aImage->LockImage();
     if (NS_SUCCEEDED(rv))
-      rv = aImage->RequestDecode();
+      rv = aImage->StartDecoding();
   }
 
   // If this is the first insertion and we're animating images, request

content/base/src/nsImageLoadingContent.cpp

@@ -268,7 +268,7 @@ nsImageLoadingContent::OnStopDecode(imgIRequest* aRequest,
   if (shell && shell->IsVisible() &&
       (!shell->DidInitialize() || shell->IsPaintingSuppressed())) {
 
-    mCurrentRequest->RequestDecode();
+    mCurrentRequest->StartDecoding();
   }
 
   // Fire the appropriate DOM event.

content/svg/content/src/nsSVGFilters.cpp

@@ -5789,7 +5789,7 @@ nsSVGFEImageElement::OnStartContainer(imgIRequest *aRequest,
 
   // Request a decode
   NS_ABORT_IF_FALSE(aContainer, "who sent the notification then?");
-  aContainer->RequestDecode();
+  aContainer->StartDecoding();
 
   // We have a size - invalidate
   Invalidate();

image/public/imgIContainer.idl

@@ -57,7 +57,7 @@ native gfxGraphicsFilter(gfxPattern::GraphicsFilter);
  *
  * Internally, imgIContainer also manages animation of images.
  */
-[scriptable, uuid(ead94080-cfd6-4a3e-8353-bd45333061d2)]
+[scriptable, uuid(d6c58749-ceb6-4afe-ab72-ff3086433e1f)]
 interface imgIContainer : nsISupports
 {
   /**
@@ -233,6 +233,11 @@ interface imgIContainer : nsISupports
    */
   void requestDecode();
 
+  /*
+   * This is equivalent to requestDecode() but it also decodes some of the image.
+   */
+  [noscript] void startDecoding();
+
   /**
     * Increments the lock count on the image. An image will not be discarded
     * as long as the lock count is nonzero. Note that it is still possible for

image/public/imgIRequest.idl

@@ -146,6 +146,7 @@ interface imgIRequest : nsIRequest
    * container does not yet exist.
    */
   void requestDecode();
+  void startDecoding();
 
   /**
    * Locks an image. If the image does not exist yet, locks it once it becomes

image/src/RasterImage.cpp

@@ -2518,13 +2518,27 @@ RasterImage::WantDecodedFrames()
   }
 
   // Request a decode (no-op if we're decoded)
-  return RequestDecode();
+  return StartDecoding();
 }
 
 //******************************************************************************
 /* void requestDecode() */
 NS_IMETHODIMP
 RasterImage::RequestDecode()
+{
+  return RequestDecodeCore(ASYNCHRONOUS);
+}
+
+/* void startDecode() */
+NS_IMETHODIMP
+RasterImage::StartDecoding()
+{
+  return RequestDecodeCore(SOMEWHAT_SYNCHRONOUS);
+}
+
+
+NS_IMETHODIMP
+RasterImage::RequestDecodeCore(RequestDecodeType aDecodeType)
 {
   nsresult rv;
 
@@ -2584,7 +2598,7 @@ RasterImage::RequestDecode()
   // If we can do decoding now, do so.  Small images will decode completely,
   // large images will decode a bit and post themselves to the event loop
   // to finish decoding.
-  if (!mDecoded && !mInDecoder && mHasSourceData) {
+  if (!mDecoded && !mInDecoder && mHasSourceData && aDecodeType == SOMEWHAT_SYNCHRONOUS) {
     SAMPLE_LABEL_PRINTF("RasterImage", "DecodeABitOf", "%s", GetURIString());
     DecodeWorker::Singleton()->DecodeABitOf(this);
     return NS_OK;

image/src/RasterImage.h

@@ -163,7 +163,8 @@ public:
   NS_IMETHOD ExtractFrame(uint32_t aWhichFrame, const nsIntRect & aRect, uint32_t aFlags, imgIContainer **_retval);
   NS_IMETHOD Draw(gfxContext *aContext, gfxPattern::GraphicsFilter aFilter, const gfxMatrix & aUserSpaceToImageSpace, const gfxRect & aFill, const nsIntRect & aSubimage, const nsIntSize & aViewportSize, uint32_t aFlags);
   NS_IMETHOD_(nsIFrame *) GetRootLayoutFrame(void);
-  NS_IMETHOD RequestDecode(void);
+  NS_IMETHOD RequestDecode();
+  NS_IMETHOD StartDecoding();
   NS_IMETHOD LockImage(void);
   NS_IMETHOD UnlockImage(void);
   NS_IMETHOD RequestDiscard(void);
@@ -688,6 +689,11 @@ private:
 
   void SetInUpdateImageContainer(bool aInUpdate) { mInUpdateImageContainer = aInUpdate; }
   bool IsInUpdateImageContainer() { return mInUpdateImageContainer; }
+  enum RequestDecodeType {
+      ASYNCHRONOUS,
+      SOMEWHAT_SYNCHRONOUS
+  };
+  NS_IMETHOD RequestDecodeCore(RequestDecodeType aDecodeType);
 
 private: // data
 
@@ -817,7 +823,7 @@ class imgDecodeRequestor : public nsRunnable
     }
     NS_IMETHOD Run() {
       if (mContainer)
-        mContainer->RequestDecode();
+        mContainer->StartDecoding();
       return NS_OK;
     }
 

image/src/VectorImage.cpp

@@ -575,6 +575,14 @@ VectorImage::RequestDecode()
   return NS_OK;
 }
 
+NS_IMETHODIMP
+VectorImage::StartDecoding()
+{
+  // Nothing to do for SVG images
+  return NS_OK;
+}
+
+
 //******************************************************************************
 /* void lockImage() */
 NS_IMETHODIMP

image/src/VectorImage.h

@@ -45,7 +45,8 @@ public:
   NS_IMETHOD ExtractFrame(uint32_t aWhichFrame, const nsIntRect & aRect, uint32_t aFlags, imgIContainer **_retval);
   NS_IMETHOD Draw(gfxContext *aContext, gfxPattern::GraphicsFilter aFilter, const gfxMatrix & aUserSpaceToImageSpace, const gfxRect & aFill, const nsIntRect & aSubimage, const nsIntSize & aViewportSize, uint32_t aFlags);
   NS_IMETHOD_(nsIFrame *) GetRootLayoutFrame(void);
-  NS_IMETHOD RequestDecode(void);
+  NS_IMETHOD RequestDecode();
+  NS_IMETHOD StartDecoding();
   NS_IMETHOD LockImage(void);
   NS_IMETHOD UnlockImage(void);
   NS_IMETHOD RequestDiscard(void);

image/src/imgRequest.cpp

@@ -496,6 +496,22 @@ imgRequest::RequestDecode()
   return NS_OK;
 }
 
+nsresult
+imgRequest::StartDecoding()
+{
+  // If we've initialized our image, we can request a decode.
+  if (mImage) {
+    return mImage->StartDecoding();
+  }
+
+  // Otherwise, flag to do it when we get the image
+  mDecodeRequested = true;
+
+  return NS_OK;
+}
+
+
+
 /** imgIContainerObserver methods **/
 
 /* [noscript] void frameChanged (in imgIRequest request,
@@ -1147,7 +1163,7 @@ imgRequest::OnDataAvailable(nsIRequest *aRequest, nsISupports *ctxt,
       if (mImage->GetType() == imgIContainer::TYPE_RASTER) {
         // If we were waiting on the image to do something, now's our chance.
         if (mDecodeRequested) {
-          mImage->RequestDecode();
+          mImage->StartDecoding();
         }
       } else { // mImage->GetType() == imgIContainer::TYPE_VECTOR
         nsCOMPtr<nsIStreamListener> imageAsStream = do_QueryInterface(mImage);

image/src/imgRequest.h

@@ -81,6 +81,7 @@ public:
   // instantiated.
   nsresult LockImage();
   nsresult UnlockImage();
+  nsresult StartDecoding();
   nsresult RequestDecode();
 
   inline void SetInnerWindowID(uint64_t aInnerWindowId) {

image/src/imgRequestProxy.cpp

@@ -177,7 +177,7 @@ nsresult imgRequestProxy::ChangeOwner(imgRequest *aNewOwner)
   // If we were decoded, or if we'd previously requested a decode, request a
   // decode on the new image
   if (wasDecoded || mDecodeRequested)
-    mOwner->RequestDecode();
+    mOwner->StartDecoding();
 
   return NS_OK;
 }
@@ -302,6 +302,20 @@ NS_IMETHODIMP imgRequestProxy::CancelAndForgetObserver(nsresult aStatus)
   return NS_OK;
 }
 
+/* void startDecode (); */
+NS_IMETHODIMP
+imgRequestProxy::StartDecoding()
+{
+  if (!mOwner)
+    return NS_ERROR_FAILURE;
+
+  // Flag this, so we know to transfer the request if our owner changes
+  mDecodeRequested = true;
+
+  // Forward the request
+  return mOwner->StartDecoding();
+}
+
 /* void requestDecode (); */
 NS_IMETHODIMP
 imgRequestProxy::RequestDecode()
@@ -316,6 +330,7 @@ imgRequestProxy::RequestDecode()
   return mOwner->RequestDecode();
 }
 
+
 /* void lockImage (); */
 NS_IMETHODIMP
 imgRequestProxy::LockImage()

layout/style/nsStyleStruct.cpp

@@ -1613,7 +1613,7 @@ nsresult
 nsStyleImage::RequestDecode() const
 {
   if ((mType == eStyleImageType_Image) && mImage)
-    return mImage->RequestDecode();
+    return mImage->StartDecoding();
   return NS_OK;
 }
 

layout/xul/base/src/nsImageBoxFrame.cpp

@@ -262,7 +262,7 @@ nsImageBoxFrame::UpdateImage()
     mIntrinsicSize.SizeTo(0, 0);
   } else {
     // We don't want discarding or decode-on-draw for xul images.
-    mImageRequest->RequestDecode();
+    mImageRequest->StartDecoding();
     mImageRequest->LockImage();
   }
 }

layout/xul/base/src/tree/src/nsTreeBodyFrame.cpp

@@ -2182,7 +2182,7 @@ nsTreeBodyFrame::GetImage(int32_t aRowIndex, nsTreeColumn* aCol, bool aUseContex
       return NS_ERROR_FAILURE;
 
     // We don't want discarding/decode-on-draw for xul images
-    imageRequest->RequestDecode();
+    imageRequest->StartDecoding();
     imageRequest->LockImage();
 
     // In a case it was already cached.

widget/cocoa/nsMenuItemIconX.mm

@@ -311,7 +311,7 @@ nsMenuItemIconX::LoadIcon(nsIURI* aIconURI)
   if (NS_FAILED(rv)) return rv;
 
   // We need to request the icon be decoded (bug 573583, bug 705516).
-  mIconRequest->RequestDecode();
+  mIconRequest->StartDecoding();
 
   return NS_OK;