Initial error handling code

src/core/SkXfermode.cpp

 
 /*
  * Copyright 2006 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 "SkXfermode.h"
@@ skipping 1420 matching lines @@
 protected:
     SkProcCoeffXfermode(SkFlattenableReadBuffer& buffer) : INHERITED(buffer) {
         fMode = (SkXfermode::Mode)buffer.read32();
 
         const ProcCoeff& rec = gProcCoeffs[fMode];
         // these may be valid, or may be CANNOT_USE_COEFF
         fSrcCoeff = rec.fSC;
         fDstCoeff = rec.fDC;
         // now update our function-ptr in the super class
         this->INHERITED::setProc(rec.fProc);
+
+        buffer.validateData(IsValidMode(fMode) &&
+                            IsValidCoeff(fSrcCoeff) &&
+                            IsValidCoeff(fDstCoeff));
     }
 
     virtual void flatten(SkFlattenableWriteBuffer& buffer) const SK_OVERRIDE {
         this->INHERITED::flatten(buffer);
         buffer.write32(fMode);
     }
 
 private:
     Mode    fMode;
     Coeff   fSrcCoeff, fDstCoeff;
@@ skipping 323 matching lines @@
     return xfer->asMode(mode);
 }
 
 bool SkXfermode::AsCoeff(const SkXfermode* xfer, Coeff* src, Coeff* dst) {
     if (NULL == xfer) {
         return ModeAsCoeff(kSrcOver_Mode, src, dst);
     }
     return xfer->asCoeff(src, dst);
 }
 
+bool SkXfermode::IsValidCoeff(Coeff coeff) {
+    return coeff >= 0 && coeff < kCoeffCount;
+}
+
 bool SkXfermode::IsMode(const SkXfermode* xfer, Mode mode) {
     // if xfer==null then the mode is srcover
     Mode m = kSrcOver_Mode;
     if (xfer && !xfer->asMode(&m)) {
         return false;
     }
     return mode == m;
 }
 
+bool SkXfermode::IsValidMode(Mode mode) {
+    return (mode >= 0) && (mode <= SkXfermode::kLastMode);
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 //////////// 16bit xfermode procs
 
 #ifdef SK_DEBUG
 static bool require_255(SkPMColor src) { return SkGetPackedA32(src) == 0xFF; }
 static bool require_0(SkPMColor src) { return SkGetPackedA32(src) == 0; }
 #endif
 
 static uint16_t src_modeproc16_255(SkPMColor src, uint16_t dst) {
     SkASSERT(require_255(src));
@@ skipping 160 matching lines @@
     return proc16;
 }
 
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_START(SkXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkProcCoeffXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkClearXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkSrcXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDstInXfermode)
     SK_DEFINE_FLATTENABLE_REGISTRAR_ENTRY(SkDstOutXfermode)
 SK_DEFINE_FLATTENABLE_REGISTRAR_GROUP_END