Implement canvas's globalCompositeOperation lighter properly....

skia/sgl/SkDraw.cpp

 /* libs/graphics/sgl/SkDraw.cpp
 **
 ** Copyright 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 
 **
@@ skipping 893 matching lines @@
         // set the mask's bounds to the transformed bitmap-bounds,
         // clipped to the actual device
         {
             SkIRect    devBounds;
             devBounds.set(0, 0, fBitmap->width(), fBitmap->height());
             // need intersect(l, t, r, b) on irect
             if (!mask.fBounds.intersect(devBounds)) {
                 return;
             }
         }
+
         mask.fFormat = SkMask::kA8_Format;
         mask.fRowBytes = SkAlign4(mask.fBounds.width());
+        size_t size = mask.computeImageSize();
+        if (0 == size) {
+            // the mask is too big to allocated, draw nothing
+            return;
+        }
 
         // allocate (and clear) our temp buffer to hold the transformed bitmap
-        size_t size = mask.computeImageSize();
         SkAutoMalloc    storage(size);
         mask.fImage = (uint8_t*)storage.get();
         memset(mask.fImage, 0, size);
         
         // now draw our bitmap(src) into mask(dst), transformed by the matrix
         {
             SkBitmap    device;
             device.setConfig(SkBitmap::kA8_Config, mask.fBounds.width(),
                              mask.fBounds.height(), mask.fRowBytes);
             device.setPixels(mask.fImage);
@@ skipping 1400 matching lines @@
                         SkMaskFilter* filter, const SkMatrix* filterMatrix,
                         SkMask* mask, SkMask::CreateMode mode) {
     if (SkMask::kJustRenderImage_CreateMode != mode) {
         if (!compute_bounds(devPath, clipBounds, filter, filterMatrix, &mask->fBounds))
             return false;
     }
     
     if (SkMask::kComputeBoundsAndRenderImage_CreateMode == mode) {
         mask->fFormat = SkMask::kA8_Format;
         mask->fRowBytes = mask->fBounds.width();
-        mask->fImage = SkMask::AllocImage(mask->computeImageSize());
+        size_t size = mask->computeImageSize();
+        if (0 == size) {
+            // we're too big to allocate the mask, abort
+            return false;
+        }
+        mask->fImage = SkMask::AllocImage(size);
         memset(mask->fImage, 0, mask->computeImageSize());
     }
 
     if (SkMask::kJustComputeBounds_CreateMode != mode) {
         draw_into_mask(*mask, devPath);
     }
     
     return true;
 }