Fixes for piping bitmaps with encoded data.

src/core/SkOrderedWriteBuffer.cpp

 
 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkOrderedWriteBuffer.h"
 #include "SkBitmap.h"
@@ skipping 127 matching lines @@
         fWriter.reservePad(length - bytesWritten);
     }
     return bytesWritten;
 }
 
 bool SkOrderedWriteBuffer::writeToStream(SkWStream* stream) {
     return fWriter.writeToStream(stream);
 }
 
 void SkOrderedWriteBuffer::writeBitmap(const SkBitmap& bitmap) {
+    // Record the width and height. This way if readBitmap fails a dummy bitmap can be drawn at the
+    // right size.
+    this->writeInt(bitmap.width());
+    this->writeInt(bitmap.height());
+
     // Record information about the bitmap in one of three ways, in order of priority:
     // 1. If there is an SkBitmapHeap, store it in the heap. The client can avoid serializing the
-    //    bitmap entirely or serialize it later as desired.
-    // 2. Write an encoded version of the bitmap. Afterwards the width and height are written, so
-    //    a reader without a decoder can draw a dummy bitmap of the right size.
+    //    bitmap entirely or serialize it later as desired. A boolean value of true will be written
+    //    to the stream to signify that a heap was used.
+    // 2. Write an encoded version of the bitmap. After writing a boolean value of false, signifying
+    //    that a heap was not used, write the size of the encoded data. A non-zero size signifies
+    //    that encoded data was written.
     //    A. If the bitmap has an encoded representation, write it to the stream.
     //    B. If there is a function for encoding bitmaps, use it.
-    // 3. Call SkBitmap::flatten.
-    // For an encoded bitmap, write the size first. Otherwise store a 0 so the reader knows not to
-    // decode.
-    if (fBitmapHeap != NULL) {
+    // 3. Call SkBitmap::flatten. After writing a boolean value of false, signifying that a heap was
+    //    not used, write a zero to signify that the data was not encoded.
+    bool useBitmapHeap = fBitmapHeap != NULL;
+    // Write a bool: true if the SkBitmapHeap is to be used, in which case the reader must use an
+    // SkBitmapHeapReader to read the SkBitmap. False if the bitmap was serialized another way.
+    this->writeBool(useBitmapHeap);
+    if (useBitmapHeap) {
         SkASSERT(NULL == fBitmapEncoder);
-        // Bitmap was not encoded. Record a zero, implying that the reader need not decode.
-        this->writeUInt(0);
         int32_t slot = fBitmapHeap->insert(bitmap);
         fWriter.write32(slot);
         // crbug.com/155875
         // The generation ID is not required information. We write it to prevent collisions
         // in SkFlatDictionary.  It is possible to get a collision when a previously
         // unflattened (i.e. stale) instance of a similar flattenable is in the dictionary
         // and the instance currently being written is re-using the same slot from the
         // bitmap heap.
         fWriter.write32(bitmap.getGenerationID());
         return;
     }
     bool encoded = false;
     // Before attempting to encode the SkBitmap, check to see if there is already an encoded
     // version.
     SkPixelRef* ref = bitmap.pixelRef();
     if (ref != NULL) {
         SkAutoDataUnref data(ref->refEncodedData());
         if (data.get() != NULL) {
             // Write the length to indicate that the bitmap was encoded successfully, followed
             // by the actual data. This must match the case where fBitmapEncoder is used so the
             // reader need not know the difference.
-            this->writeUInt(data->size());
+            this->writeUInt(SkToU32(data->size()));
             fWriter.writePad(data->data(), data->size());
             encoded = true;
         }
     }
     if (fBitmapEncoder != NULL && !encoded) {
         SkASSERT(NULL == fBitmapHeap);
         SkDynamicMemoryWStream stream;
         if (fBitmapEncoder(&stream, bitmap)) {
             uint32_t offset = fWriter.bytesWritten();
             // Write the length to indicate that the bitmap was encoded successfully, followed
             // by the actual data. This must match the case where the original data is used so the
             // reader need not know the difference.
             size_t length = stream.getOffset();
-            this->writeUInt(length);
+            this->writeUInt(SkToU32(length));
             if (stream.read(fWriter.reservePad(length), 0, length)) {
                 encoded = true;
             } else {
                 // Writing the stream failed, so go back to original state to store another way.
                 fWriter.rewindToOffset(offset);
             }
         }
     }
-    if (encoded) {
-        // Write the width and height in case the reader does not have a decoder.
-        this->writeInt(bitmap.width());
-        this->writeInt(bitmap.height());
-    } else {
+    if (!encoded) {
         // Bitmap was not encoded. Record a zero, implying that the reader need not decode.
         this->writeUInt(0);
         bitmap.flatten(*this);
     }
 }
 
 void SkOrderedWriteBuffer::writeTypeface(SkTypeface* obj) {
     if (NULL == obj || NULL == fTFSet) {
         fWriter.write32(0);
     } else {
@@ skipping 93 matching lines @@
     // make room for the size of the flattened object
     (void)fWriter.reserve(sizeof(uint32_t));
     // record the current size, so we can subtract after the object writes.
     uint32_t offset = fWriter.size();
     // now flatten the object
     flattenObject(flattenable, *this);
     uint32_t objSize = fWriter.size() - offset;
     // record the obj's size
     *fWriter.peek32(offset - sizeof(uint32_t)) = objSize;
 }