detect bad bitmaps during deserialization

src/core/SkReadBuffer.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 "SkBitmap.h"
 #include "SkErrorInternals.h"
@@ skipping 241 matching lines @@
                 SkBitmap subsetBm;
                 SkIRect subset = SkIRect::MakeXYWH(xOffset, yOffset, width, height);
                 if (bitmap->extractSubset(&subsetBm, subset)) {
                     bitmap->swap(subsetBm);
                     return true;
                 }
             }
             // This bitmap was encoded when written, but we are unable to decode, possibly due to
             // not having a decoder.
             SkErrorInternals::SetError(kParseError_SkError,
                                        "Could not decode bitmap. Resulting bitmap will be red.");

[scroggo, 2014/11/12 18:24:48]

I think this error message is well out of date.

[reed1, 2014/11/12 19:25:19]

Yea, esp. the RED part. I will update.

+            // Even though we weren't able to decode the pixels, the readbuffer should still be
+            // intact, so we return true with an empty bitmap, so we don't for an abort of the

[scroggo, 2014/11/12 18:24:48]

force* ?

[reed1, 2014/11/12 19:25:19]

Acknowledged.

+            // larger deserialize.
+            bitmap->setInfo(SkImageInfo::MakeUnknown(width, height));
+            return true;
         } else {
             // A size of zero means the SkBitmap was simply flattened.
             if (this->isVersionLT(kNoMoreBitmapFlatten_Version)) {
                 SkBitmap tmp;
                 tmp.legacyUnflatten(*this);
                 // just throw this guy away

[scroggo, 2014/11/12 18:24:48]

This will fall through and return false. With the change in SkPictureData.cpp,
this means we'll abort the picture, right? Does this mean that older SKPs may
not work anymore? Is that okay?

[reed1, 2014/11/12 19:25:19]

This is effectively dead code, which I will clean up later. legacyUnflatten()
crashes, so we never actually return from it.

             } else {
                 if (SkBitmap::ReadRawPixels(this, bitmap)) {
                     return true;
                 }
             }
         }
     }
     // Could not read the SkBitmap. Use a placeholder bitmap.
     bitmap->setInfo(SkImageInfo::MakeUnknown(width, height));
     return false;
@@ skipping 76 matching lines @@
             return;
         }
     } else {
         if (NULL == this->readFunctionPtr()) {
             return;
         }
     }
     uint32_t sizeRecorded = fReader.readU32();
     fReader.skip(sizeRecorded);
 }