Initial error handling code

src/core/SkValidatingReadBuffer.h

+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkValidatingReadBuffer_DEFINED
+#define SkValidatingReadBuffer_DEFINED
+
+#include "SkRefCnt.h"
+#include "SkBitmapHeap.h"
+#include "SkFlattenableBuffers.h"
+#include "SkPath.h"
+#include "SkPicture.h"
+#include "SkReader32.h"
+
+class SkBitmap;
+
+class SkValidatingReadBuffer : public SkFlattenableReadBuffer {
+public:
+    SkValidatingReadBuffer(const void* data, size_t size);
+    virtual ~SkValidatingReadBuffer();
+
+    const void* skip(size_t size);
+
+    // primitives
+    virtual bool readBool() SK_OVERRIDE;
+    virtual SkColor readColor() SK_OVERRIDE;
+    virtual SkFixed readFixed() SK_OVERRIDE;
+    virtual int32_t readInt() SK_OVERRIDE;
+    virtual SkScalar readScalar() SK_OVERRIDE;
+    virtual uint32_t readUInt() SK_OVERRIDE;
+    virtual int32_t read32() SK_OVERRIDE;
+
+    // strings -- the caller is responsible for freeing the string contents
+    virtual void readString(SkString* string) SK_OVERRIDE;
+    virtual void* readEncodedString(size_t* length, SkPaint::TextEncoding encoding) SK_OVERRIDE;
+
+    // common data structures
+    virtual SkFlattenable* readFlattenable(
+        const char* name = SkFlattenable::GetTypeName()) SK_OVERRIDE;
+    virtual void readPoint(SkPoint* point) SK_OVERRIDE;
+    virtual void readMatrix(SkMatrix* matrix) SK_OVERRIDE;
+    virtual void readIRect(SkIRect* rect) SK_OVERRIDE;
+    virtual void readRect(SkRect* rect) SK_OVERRIDE;
+    virtual void readRegion(SkRegion* region) SK_OVERRIDE;
+    virtual void readPath(SkPath* path) SK_OVERRIDE;
+
+    // binary data and arrays
+    virtual uint32_t readByteArray(void* value) SK_OVERRIDE;
+    virtual uint32_t readColorArray(SkColor* colors) SK_OVERRIDE;
+    virtual uint32_t readIntArray(int32_t* values) SK_OVERRIDE;
+    virtual uint32_t readPointArray(SkPoint* points) SK_OVERRIDE;
+    virtual uint32_t readScalarArray(SkScalar* values) SK_OVERRIDE;
+
+    // helpers to get info about arrays and binary data
+    virtual uint32_t getArrayCount() SK_OVERRIDE;
+
+    virtual void readBitmap(SkBitmap* bitmap) SK_OVERRIDE;
+    // TODO: Implement this (securely) when needed
+    virtual SkTypeface* readTypeface() SK_OVERRIDE { return NULL; }
+
+    virtual void validate(bool isValid) SK_OVERRIDE {
+        fError = fError || !isValid;
+    }
+
+private:
+    void setMemory(const void* data, size_t size);
+
+    static bool IsPtrAlign4(const void* ptr) {
+        return SkIsAlign4((uintptr_t)ptr);
+    }
+
+    SkReader32 fReader;
+    bool fError;
+
+    typedef SkFlattenableReadBuffer INHERITED;
+};
+
+#endif // SkValidatingReadBuffer_DEFINED