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;
+
+#if defined(SK_DEBUG) && defined(SK_BUILD_FOR_MAC)
+    #define DEBUG_NON_DETERMINISTIC_ASSERT
+#endif
+
+class SkValidatingReadBuffer : public SkFlattenableReadBuffer {

[mtklein, 2013/09/24 22:52:18]

Looks like a solid copy and paste.  :)  How much of this API (and members) can
we cut away?  At a glance, seems like getReader32 should go, as should the
various setBitmapStorage, setTypefaceArray, setFactoryPlayback, etc.

In fact, are there any methods that aren't SK_OVERRIDE that we can't remove? 
Let's just blow away the lot to get this as trimmed down as possible.

[sugoi1, 2013/09/25 21:15:27]

I removed everything except skip(), which I'm using, and readTypeface() now
returns NULL until we need to implement it (but I still need to declare it
here).

+public:
+    SkValidatingReadBuffer();
+    SkValidatingReadBuffer(const void* data, size_t size);
+    SkValidatingReadBuffer(SkStream* stream);
+    virtual ~SkValidatingReadBuffer();
+
+    SkReader32* getReader32() { return &fReader; }
+
+    uint32_t size() { return fReader.size(); }
+    uint32_t offset() { return fReader.offset(); }
+    bool eof() { return fReader.eof(); }
+    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(
+        SkFlattenable::Type type = SkFlattenable::kSkFlattenable) 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;
+    virtual SkTypeface* readTypeface() SK_OVERRIDE;
+
+    void setBitmapStorage(SkBitmapHeapReader* bitmapStorage) {
+        SkRefCnt_SafeAssign(fBitmapStorage, bitmapStorage);
+    }
+
+    void setTypefaceArray(SkTypeface* array[], int count) {
+        fTFArray = array;
+        fTFCount = count;
+    }
+
+    /**
+     *  Call this with a pre-loaded array of Factories, in the same order as
+     *  were created/written by the writer. SkPicture uses this.
+     */
+    void setFactoryPlayback(SkFlattenable::Factory array[], int count) {
+        fFactoryTDArray = NULL;
+        fFactoryArray = array;
+        fFactoryCount = count;
+    }
+
+    /**
+     *  Call this with an initially empty array, so the reader can cache each
+     *  factory it sees by name. Used by the pipe code in conjunction with
+     *  SkOrderedWriteBuffer::setNamedFactoryRecorder.
+     */
+    void setFactoryArray(SkTDArray<SkFlattenable::Factory>* array) {
+        fFactoryTDArray = array;
+        fFactoryArray = NULL;
+        fFactoryCount = 0;
+    }
+
+    /**
+     *  Provide a function to decode an SkBitmap from encoded data. Only used if the writer
+     *  encoded the SkBitmap. If the proper decoder cannot be used, a red bitmap with the
+     *  appropriate size will be used.
+     */
+    void setBitmapDecoder(SkPicture::InstallPixelRefProc bitmapDecoder) {
+        fBitmapDecoder = bitmapDecoder;
+    }
+
+private:
+    void setMemory(const void* data, size_t size);
+
+    static bool ptr_align_4(const void* ptr) {

[mtklein, 2013/09/24 22:52:18]

I think we typically make static methods camel case.  IsPtrAlign4?

[sugoi1, 2013/09/25 21:15:27]

Done.

+        return (((const char*)ptr - (const char*)NULL) & 3) == 0;

[mtklein, 2013/09/24 22:52:18]

return (uintptr_t)ptr & 3 == 0?,  or better yet SkIsAlign4((uintptr_t)ptr) ?

[sugoi1, 2013/09/25 21:15:27]

Done.

+    }
+
+    SkReader32 fReader;
+    void* fMemoryPtr;
+
+    SkBitmapHeapReader* fBitmapStorage;
+    SkTypeface** fTFArray;
+    int        fTFCount;
+
+    SkTDArray<SkFlattenable::Factory>* fFactoryTDArray;
+    SkFlattenable::Factory* fFactoryArray;
+    int                     fFactoryCount;
+
+    SkPicture::InstallPixelRefProc fBitmapDecoder;
+
+#ifdef DEBUG_NON_DETERMINISTIC_ASSERT

[mtklein, 2013/09/24 22:52:18]

I think we can throw this feature out too for now.  It's probably not even used
in SkOrderedReadBuffer anymore.

[sugoi1, 2013/09/25 21:15:27]

Done.

+    // Debugging counter to keep track of how many bitmaps we
+    // have decoded.
+    int fDecodedBitmapIndex;
+#endif // DEBUG_NON_DETERMINISTIC_ASSERT
+
+    typedef SkFlattenableReadBuffer INHERITED;
+};
+
+#endif // SkValidatingReadBuffer_DEFINED