cache private readback for gpu-images

src/image/SkImage_Gpu.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
+#include "SkBitmapCache.h"
 #include "SkImage_Gpu.h"
 #include "GrContext.h"
 #include "GrDrawContext.h"
 #include "effects/GrYUVtoRGBEffect.h"
 #include "SkCanvas.h"
 #include "SkGpuDevice.h"
-
+#include "SkPixelRef.h"
 
 SkImage_Gpu::SkImage_Gpu(int w, int h, uint32_t uniqueID, SkAlphaType at, GrTexture* tex,
                          int sampleCountForNewSurfaces, SkSurface::Budgeted budgeted)
     : INHERITED(w, h, uniqueID, NULL)
     , fTexture(SkRef(tex))
     , fSampleCountForNewSurfaces(sampleCountForNewSurfaces)
     , fAlphaType(at)
     , fBudgeted(budgeted)
     {}
 
+SkImage_Gpu::~SkImage_Gpu() {
+    if (fAddedRasterVersionToCache.load()) {
+        SkNotifyBitmapGenIDIsStale(this->uniqueID());
+    }
+}
+
 SkSurface* SkImage_Gpu::onNewSurface(const SkImageInfo& info, const SkSurfaceProps& props) const {
     GrTexture* tex = this->getTexture();
     SkASSERT(tex);
     GrContext* ctx = tex->getContext();
     if (!ctx) {
         // the texture may have been abandoned, so we have to check
         return NULL;
     }
     // TODO: Change signature of onNewSurface to take a budgeted param.
     const SkSurface::Budgeted budgeted = SkSurface::kNo_Budgeted;
     return SkSurface::NewRenderTarget(ctx, budgeted, info, fSampleCountForNewSurfaces, &props);
 }
 
 extern void SkTextureImageApplyBudgetedDecision(SkImage* image) {
     if (as_IB(image)->getTexture()) {
         ((SkImage_Gpu*)image)->applyBudgetDecision();
     }
 }
 
 SkShader* SkImage_Gpu::onNewShader(SkShader::TileMode tileX, SkShader::TileMode tileY,
                                    const SkMatrix* localMatrix) const {
     SkBitmap bm;
     GrWrapTextureInBitmap(fTexture, this->width(), this->height(), this->isOpaque(), &bm);
     return SkShader::CreateBitmapShader(bm, tileX, tileY, localMatrix);
 }
 
 bool SkImage_Gpu::getROPixels(SkBitmap* dst) const {
+    if (SkBitmapCache::Find(this->uniqueID(), dst)) {
+        SkASSERT(dst->getGenerationID() == this->uniqueID());
+        SkASSERT(dst->isImmutable());
+        SkASSERT(dst->getPixels());
+        return true;
+    }
+
     SkAlphaType at = this->isOpaque() ? kOpaque_SkAlphaType : kPremul_SkAlphaType;
     if (!dst->tryAllocPixels(SkImageInfo::MakeN32(this->width(), this->height(), at))) {
         return false;
     }
     if (!fTexture->readPixels(0, 0, dst->width(), dst->height(), kSkia8888_GrPixelConfig,
                               dst->getPixels(), dst->rowBytes())) {
         return false;
     }
+
+    dst->pixelRef()->setImmutableWithID(this->uniqueID());
+    SkBitmapCache::Add(this->uniqueID(), *dst);
+    fAddedRasterVersionToCache.store(true);
     return true;
 }
 
 bool SkImage_Gpu::isOpaque() const {
     return GrPixelConfigIsOpaque(fTexture->config()) || fAlphaType == kOpaque_SkAlphaType;
 }
 
 static void apply_premul(const SkImageInfo& info, void* pixels, size_t rowBytes) {
     switch (info.colorType()) {
         case kRGBA_8888_SkColorType:
@@ skipping 183 matching lines @@
     if (!dst) {
         return NULL;
     }
     
     const SkIRect srcR = SkIRect::MakeWH(desc.fWidth, desc.fHeight);
     const SkIPoint dstP = SkIPoint::Make(0, 0);
     ctx->copySurface(dst, src, srcR, dstP, GrContext::kFlushWrites_PixelOp);
     return dst;
 }