read/write function_ptrs as just void*, and not as 'array of bytes'

include/core/SkReadBuffer.h

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkReadBuffer_DEFINED
 #define SkReadBuffer_DEFINED
@@ skipping 55 matching lines @@
     bool isScalarFloat() const { return SkToBool(fFlags & kScalarIsFloat_Flag); }
     bool isPtr64Bit() const { return SkToBool(fFlags & kPtrIs64Bit_Flag); }
     bool isValidating() const { return SkToBool(fFlags & kValidation_Flag); }
 
     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) { return fReader.skip(size); }
+    void* readFunctionPtr() { return fReader.readPtr(); }

[bungeman-skia, 2014/04/16 16:51:36]

So, I think this was 'incorrect' before, so this change makes no real
difference. However, it is technically undefined to cast a function pointer to a
void pointer. POSIX defines the way we do things in the call to dlsym in
SkFontHost_FreeType.cpp (because dlsym is defined to return a void*). Windows is
actually better here, as GetProcAddress returns FARPROC which is actually a
function pointer.

The spec does state that you can cast a function pointer to another one, so long
as it is cast back to the original before making a call through it. I would
propose a 'typedef void (*SkVoidProc)()' which would be what this and the
associated writer would deal in.

 
     // primitives
     virtual bool readBool();
     virtual SkColor readColor();
     virtual SkFixed readFixed();
     virtual int32_t readInt();
     virtual SkScalar readScalar();
     virtual uint32_t readUInt();
     virtual int32_t read32();
 
-    void* readFunctionPtr() {
-        void* ptr;
-        this->readByteArray(&ptr, sizeof(ptr));
-        return ptr;
-    }
-
     // strings -- the caller is responsible for freeing the string contents
     virtual void readString(SkString* string);
     virtual void* readEncodedString(size_t* length, SkPaint::TextEncoding encoding);
 
     // common data structures
     virtual void readPoint(SkPoint* point);
     SkPoint readPoint() { SkPoint p; this->readPoint(&p); return p; }
     virtual void readMatrix(SkMatrix* matrix);
     virtual void readIRect(SkIRect* rect);
     virtual void readRect(SkRect* rect);
@@ skipping 106 matching lines @@
     SkPicture::InstallPixelRefProc fBitmapDecoder;
 
 #ifdef DEBUG_NON_DETERMINISTIC_ASSERT
     // Debugging counter to keep track of how many bitmaps we
     // have decoded.
     int fDecodedBitmapIndex;
 #endif // DEBUG_NON_DETERMINISTIC_ASSERT
 };
 
 #endif // SkReadBuffer_DEFINED