Bug 1285867 (Part 3e) - Use TerminalState to exit the Decode() loop. r=edwin

image/Decoder.cpp

@@ -164,10 +164,6 @@ Decoder::Decode(NotNull<IResumable*> aOnResume)
         // Pass the data along to the implementation.
         terminalState = DoDecode(*mIterator);
 
-        if (terminalState == Some(TerminalState::FAILURE)) {
-          PostDataError();
-        }
-
         break;
       }
 
@@ -175,7 +171,12 @@ Decoder::Decode(NotNull<IResumable*> aOnResume)
         MOZ_ASSERT_UNREACHABLE("Unknown SourceBufferIterator state");
         terminalState = Some(TerminalState::FAILURE);
     }
-  } while (!GetDecodeDone() && !HasError());
+  } while (!GetDecodeDone() && !terminalState);
+
+  // If decoding failed, record that fact.
+  if (terminalState == Some(TerminalState::FAILURE)) {
+    PostDataError();
+  }
 
   CompleteDecode();
   return HasError() ? NS_ERROR_FAILURE : NS_OK;

image/decoders/nsBMPDecoder.cpp

@@ -262,12 +262,19 @@ nsBMPDecoder::FinishInternal()
     nsIntRect r(0, 0, mH.mWidth, AbsoluteHeight());
     PostInvalidation(r);
 
-    if (mDoesHaveTransparency) {
-      MOZ_ASSERT(mMayHaveTransparency);
-      PostFrameStop(Opacity::SOME_TRANSPARENCY);
-    } else {
-      PostFrameStop(Opacity::FULLY_OPAQUE);
-    }
+    MOZ_ASSERT_IF(mDoesHaveTransparency, mMayHaveTransparency);
+
+    // We have transparency if we either detected some in the image itself
+    // (i.e., |mDoesHaveTransparency| is true) or we're in an ICO, which could
+    // mean we have an AND mask that provides transparency (i.e., |mIsWithinICO|
+    // is true).
+    // XXX(seth): We can tell when we create the decoder if the AND mask is
+    // present, so we could be more precise about this.
+    const Opacity opacity = mDoesHaveTransparency || mIsWithinICO
+                          ? Opacity::SOME_TRANSPARENCY
+                          : Opacity::FULLY_OPAQUE;
+
+    PostFrameStop(opacity);
     PostDecodeDone();
   }
 

image/decoders/nsBMPDecoder.h

@@ -142,13 +142,6 @@ public:
   /// bitmap has been fully decoded.)
   bool HasTransparency() const { return mDoesHaveTransparency; }
 
-  /// Force transparency from outside. (Used by the ICO decoder.)
-  void SetHasTransparency()
-  {
-    mMayHaveTransparency = true;
-    mDoesHaveTransparency = true;
-  }
-
   Maybe<TerminalState> DoDecode(SourceBufferIterator& aIterator) override;
   nsresult BeforeFinishInternal() override;
   nsresult FinishInternal() override;

image/decoders/nsICODecoder.cpp

@@ -573,15 +573,6 @@ nsICODecoder::FinishMask()
     }
   }
 
-  // If the mask contained any transparent pixels, record that fact.
-  if (mHasMaskAlpha) {
-    PostHasTransparency();
-
-    RefPtr<nsBMPDecoder> bmpDecoder =
-      static_cast<nsBMPDecoder*>(mContainedDecoder.get());
-    bmpDecoder->SetHasTransparency();
-  }
-
   return Transition::To(ICOState::FINISHED_RESOURCE, 0);
 }