Add a detachAsStream to SkDynamicMemoryWStream.

include/core/SkStream.h

 /*
  * 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.
  */
 
 #ifndef SkStream_DEFINED
 #define SkStream_DEFINED
 
@@ skipping 262 matching lines @@
     virtual bool rewind() SK_OVERRIDE;
     virtual SkStreamAsset* duplicate() const SK_OVERRIDE;
 
     virtual size_t getPosition() const SK_OVERRIDE;
     virtual bool seek(size_t position) SK_OVERRIDE;
     virtual bool move(long offset) SK_OVERRIDE;
     virtual SkStreamAsset* fork() const SK_OVERRIDE;
 
     virtual size_t getLength() const SK_OVERRIDE;
 
-    const void* getMemoryBase() SK_OVERRIDE;
+    virtual const void* getMemoryBase() SK_OVERRIDE;
 
 private:
     SkFILE*     fFILE;
     SkString    fName;
     Ownership   fOwnership;
     // fData is lazilly initialized when needed.
     mutable SkAutoTUnref<SkData> fData;
 
     typedef SkStreamAsset INHERITED;
 };
@@ skipping 114 matching lines @@
 
     virtual bool write(const void* buffer, size_t size) SK_OVERRIDE;
     // random access write
     // modifies stream and returns true if offset + size is less than or equal to getOffset()
     bool write(const void* buffer, size_t offset, size_t size);
     bool read(void* buffer, size_t offset, size_t size);
     size_t getOffset() const { return fBytesWritten; }
     size_t bytesWritten() const { return fBytesWritten; }
 
     // copy what has been written to the stream into dst
     void copyTo(void* dst) const;

[reed1, 2013/07/17 20:58:47]

I wish this guy would return size_t number of bytes, so it can be used with NULL
and then w/o to size the dst buffer... just saying.

[bungeman-skia, 2013/07/17 21:29:48]

That's what ::bytesWritten() is for. To clarify, this isn't just about doing one
copy, but also about being able to pass the data around looking like a SkStream.

 
     /**
      *  Return a copy of the data written so far. This call is responsible for
      *  calling unref() when they are finished with the data.
      */
     SkData* copyToData() const;
 
-    // reset the stream to its original state
+    /** Reset, returning a reader stream with the current content. */
+    SkStreamAsset* detatchAsStream();
+
+    /** Reset the stream to its original, empty, state. */
     void reset();
     void padToAlign4();
 private:
     struct Block;
     Block*  fHead;
     Block*  fTail;
     size_t  fBytesWritten;
     mutable SkData* fCopy;  // is invalidated if we write after it is created
 
     void invalidateCopy();
 
+    // For access to the Block type.
+    friend class SkBlockMemoryStream;
+    friend class SkBlockMemoryRefCnt;
+
     typedef SkWStream INHERITED;
 };
 
 
 class SK_API SkDebugWStream : public SkWStream {
 public:
     SK_DECLARE_INST_COUNT(SkDebugWStream)
 
     // overrides
     virtual bool write(const void* buffer, size_t size) SK_OVERRIDE;
     virtual void newline() SK_OVERRIDE;
 
 private:
     typedef SkWStream INHERITED;
 };
 
 // for now
 typedef SkFILEStream SkURLStream;
 
 #endif