add SkPixmap and external locking to bitmaps

include/core/SkBitmap.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 SkBitmap_DEFINED
 #define SkBitmap_DEFINED
 
 #include "SkColor.h"
 #include "SkColorTable.h"
 #include "SkImageInfo.h"
+#include "SkPixmap.h"
 #include "SkPoint.h"
 #include "SkRefCnt.h"
 
 struct SkMask;
 struct SkIRect;
 struct SkRect;
 class SkPaint;
 class SkPixelRef;
 class SkPixelRefFactory;
 class SkRegion;
@@ skipping 397 matching lines @@
     void unlockPixels() const;
 
     /**
      *  Some bitmaps can return a copy of their pixels for lockPixels(), but
      *  that copy, if modified, will not be pushed back. These bitmaps should
      *  not be used as targets for a raster device/canvas (since all pixels
      *  modifications will be lost when unlockPixels() is called.)
      */
     bool lockPixelsAreWritable() const;
 
+    class LockResult {

[scroggo, 2015/05/19 20:11:41]

inherit from SkNoncopyable?

[reed1, 2015/05/21 20:59:34]

Done.

+    public:
+        LockResult() : fUnlockProc(NULL), fUnlockContext(NULL) {
+            SkDEBUGCODE(fIsLocked = false;)
+        }
+
+        const SkPixmap& pixmap() const { return fPixmap; }
+
+        SkDEBUGCODE(bool isLocked() const { return fIsLocked; })
+        void unlock();

[scroggo, 2015/05/19 20:11:42]

Should this get called by a destructor, if it wasn't called before?

[reed1, 2015/05/21 20:59:34]

Done.

+
+    private:
+        LockResult(const SkPixmap& pm, void (*unlock)(void*), void* ctx)
+            : fUnlockProc(unlock), fUnlockContext(ctx), fPixmap(pm)
+        {
+            SkDEBUGCODE(fIsLocked = true;)
+        }
+
+        void        (*fUnlockProc)(void*);
+        void*       fUnlockContext;
+        SkPixmap    fPixmap;
+        SkDEBUGCODE(bool fIsLocked;)
+
+        friend class SkBitmap;
+    };
+
+    bool requestLock(LockResult* result) const;
+
     /** Call this to be sure that the bitmap is valid enough to be drawn (i.e.
         it has non-null pixels, and if required by its colortype, it has a
         non-null colortable. Returns true if all of the above are met.
     */
     bool readyToDraw() const {
         return this->getPixels() != NULL &&
                (this->colorType() != kIndex_8_SkColorType || fColorTable);
     }
 
     /** Returns the pixelRef's texture, or NULL
@@ skipping 335 matching lines @@
         }
     }
 
 private:
     const SkBitmap& fBitmap;
     bool            fDidLock;
 };
 //TODO(mtklein): uncomment when 71713004 lands and Chromium's fixed.
 //#define SkAutoLockPixels(...) SK_REQUIRE_LOCAL_VAR(SkAutoLockPixels)
 
+class SkAutoBitmapLockResult : public SkBitmap::LockResult {
+public:
+    SkAutoBitmapLockResult() {}
+    ~SkAutoBitmapLockResult() {
+        this->unlock();
+    }
+};
+
 ///////////////////////////////////////////////////////////////////////////////
 
 inline uint32_t* SkBitmap::getAddr32(int x, int y) const {
     SkASSERT(fPixels);
     SkASSERT(4 == this->bytesPerPixel());
     SkASSERT((unsigned)x < (unsigned)this->width() && (unsigned)y < (unsigned)this->height());
     return (uint32_t*)((char*)fPixels + y * fRowBytes + (x << 2));
 }
 
 inline uint16_t* SkBitmap::getAddr16(int x, int y) const {
@@ skipping 12 matching lines @@
 
 inline SkPMColor SkBitmap::getIndex8Color(int x, int y) const {
     SkASSERT(fPixels);
     SkASSERT(kIndex_8_SkColorType == this->colorType());
     SkASSERT((unsigned)x < (unsigned)this->width() && (unsigned)y < (unsigned)this->height());
     SkASSERT(fColorTable);
     return (*fColorTable)[*((const uint8_t*)fPixels + y * fRowBytes + x)];
 }
 
 #endif