Initial error handling code

src/effects/SkMatrixConvolutionImageFilter.cpp

 /*
  * Copyright 2012 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkMatrixConvolutionImageFilter.h"
 #include "SkBitmap.h"
 #include "SkColorPriv.h"
 #include "SkFlattenableBuffers.h"
 #include "SkRect.h"
 #include "SkUnPreMultiply.h"
 
 #if SK_SUPPORT_GPU
 #include "gl/GrGLEffect.h"
 #include "gl/GrGLEffectMatrix.h"
 #include "effects/GrSingleTextureEffect.h"
 #include "GrTBackendEffectFactory.h"
 #include "GrTexture.h"
 #include "SkMatrix.h"
 
 #endif
 
+namespace {
+
+bool TileModeIsValid(SkMatrixConvolutionImageFilter::TileMode tileMode) {
+    switch (tileMode) {
+    case SkMatrixConvolutionImageFilter::kClamp_TileMode:
+    case SkMatrixConvolutionImageFilter::kRepeat_TileMode:
+    case SkMatrixConvolutionImageFilter::kClampToBlack_TileMode:
+        return true;
+    default:
+        break;
+    }
+    return false;
+}
+
+}
+
 SkMatrixConvolutionImageFilter::SkMatrixConvolutionImageFilter(const SkISize& kernelSize, const SkScalar* kernel, SkScalar gain, SkScalar bias, const SkIPoint& target, TileMode tileMode, bool convolveAlpha, SkImageFilter* input)
   : INHERITED(input),
     fKernelSize(kernelSize),
     fGain(gain),
     fBias(bias),
     fTarget(target),
     fTileMode(tileMode),
     fConvolveAlpha(convolveAlpha) {
     uint32_t size = fKernelSize.fWidth * fKernelSize.fHeight;
     fKernel = SkNEW_ARRAY(SkScalar, size);
     memcpy(fKernel, kernel, size * sizeof(SkScalar));
     SkASSERT(kernelSize.fWidth >= 1 && kernelSize.fHeight >= 1);
     SkASSERT(target.fX >= 0 && target.fX < kernelSize.fWidth);
     SkASSERT(target.fY >= 0 && target.fY < kernelSize.fHeight);
 }
 
 SkMatrixConvolutionImageFilter::SkMatrixConvolutionImageFilter(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {
     fKernelSize.fWidth = buffer.readInt();
     fKernelSize.fHeight = buffer.readInt();
     uint32_t size = fKernelSize.fWidth * fKernelSize.fHeight;
     fKernel = SkNEW_ARRAY(SkScalar, size);

[Stephen White, 2013/09/09 17:43:00]

We should probably add some test cases with impossible-to-allocate sizes, if we
don't have them already.

     SkDEBUGCODE(uint32_t readSize = )buffer.readScalarArray(fKernel);
     SkASSERT(readSize == size);
     fGain = buffer.readScalar();
     fBias = buffer.readScalar();
     fTarget.fX = buffer.readInt();
     fTarget.fY = buffer.readInt();
     fTileMode = (TileMode) buffer.readInt();
     fConvolveAlpha = buffer.readBool();

[Stephen White, 2013/09/09 17:43:00]

Can readBool() ever get weird values? Or does it internally self-validate?

+    buffer.validateData(SkScalarIsFinite(fGain) &&
+                        SkScalarIsFinite(fBias) &&
+                        TileModeIsValid(fTileMode));
 }
 
 void SkMatrixConvolutionImageFilter::flatten(SkFlattenableWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
     buffer.writeInt(fKernelSize.fWidth);
     buffer.writeInt(fKernelSize.fHeight);
     buffer.writeScalarArray(fKernel, fKernelSize.fWidth * fKernelSize.fHeight);
     buffer.writeScalar(fGain);
     buffer.writeScalar(fBias);
     buffer.writeInt(fTarget.fX);
@@ skipping 509 matching lines @@
                                                 fBias,
                                                 fTarget,
                                                 fTileMode,
                                                 fConvolveAlpha);
     return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 #endif