1 files changed, 55 insertions, 20 deletions

diff --git a/skia/include/SkImageDecoder.h b/skia/include/SkImageDecoder.h
index 8a93ef9..e6389e4 100644
--- a/skia/include/SkImageDecoder.h
+++ b/skia/include/SkImageDecoder.h
@@ -1,19 +1,18 @@
-/* include/graphics/SkImageDecoder.h
-**
-** Copyright 2006, Google Inc.
-**
-** Licensed under the Apache License, Version 2.0 (the "License"); 
-** you may not use this file except in compliance with the License. 
-** You may obtain a copy of the License at 
-**
-**     http://www.apache.org/licenses/LICENSE-2.0 
-**
-** Unless required by applicable law or agreed to in writing, software 
-** distributed under the License is distributed on an "AS IS" BASIS, 
-** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
-** See the License for the specific language governing permissions and 
-** limitations under the License.
-*/
+/*
+ * Copyright (C) 2006 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 
 #ifndef SkImageDecoder_DEFINED
 #define SkImageDecoder_DEFINED
@@ -101,8 +100,28 @@ public:
     // approximate the sample size.
     int getSampleSize() const { return fSampleSize; }
     void setSampleSize(int size);
+    
+    /** Reset the sampleSize to its default of 1
+     */
     void resetSampleSize() { this->setSampleSize(1); }
 
+    /** Decoding is synchronous, but for long decodes, a different thread can
+        call this method safely. This sets a state that the decoders will
+        periodically check, and if they see it changed to cancel, they will
+        cancel. This will result in decode() returning false. However, there is
+        no guarantee that the decoder will see the state change in time, so
+        it is possible that cancelDecode() will be called, but will be ignored
+        and decode() will return true (assuming no other problems were
+        encountered).
+     
+        This state is automatically reset at the beginning of decode().
+     */
+    void cancelDecode() {
+        // now the subclass must query shouldCancelDecode() to be informed
+        // of the request
+        fShouldCancelDecode = true;
+    }
+
     /** Passed to the decode method. If kDecodeBounds_Mode is passed, then
         only the bitmap's width/height/config need be set. If kDecodePixels_Mode
         is passed, then the bitmap must have pixels or a pixelRef.
@@ -120,10 +139,9 @@ public:
         bitmap. It can then set the pixels with the decompressed image.
         If the image cannot be decompressed, return false.
         
-        note: document use of Allocator, Peeker and Chooser <reed>
+        note: document use of Allocator, Peeker and Chooser 
     */
-    virtual bool onDecode(SkStream*, SkBitmap* bitmap, SkBitmap::Config pref,
-                          Mode) = 0;
+    bool decode(SkStream*, SkBitmap* bitmap, SkBitmap::Config pref, Mode);
 
     /** Given a stream, this will try to find an appropriate decoder object.
         If none is found, the method returns NULL.
@@ -206,6 +224,23 @@ public:
   /** @endcond */
 
 protected:
+    // must be overridden in subclasses. This guy is called by decode(...)
+    virtual bool onDecode(SkStream*, SkBitmap* bitmap, SkBitmap::Config pref,
+                          Mode) = 0;
+
+    /** Can be queried from within onDecode, to see if the user (possibly in
+        a different thread) has requested the decode to cancel. If this returns
+        true, your onDecode() should stop and return false.
+        Each subclass needs to decide how often it can query this, to balance
+        responsiveness with performance.
+     
+        Calling this outside of onDecode() may return undefined values.
+     */
+
+public:
+    bool shouldCancelDecode() const { return fShouldCancelDecode; }
+
+protected:    
     SkImageDecoder();
 
     // helper function for decoders to handle the (common) case where there is only
@@ -224,6 +259,7 @@ private:
     SkBitmap::Allocator*    fAllocator;
     int                     fSampleSize;
     bool                    fDitherImage;
+    mutable bool            fShouldCancelDecode;
 
     // illegal
     SkImageDecoder(const SkImageDecoder&);
@@ -258,4 +294,3 @@ protected:
 ///////////////////////////////////////////////////////////////////////
 
 #endif
-