Proactive SkPixelRef invalidation

src/gpu/SkGr.cpp

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGr.h"
 #include "SkConfig8888.h"
+#include "SkMessageBus.h"
+#include "SkPixelRef.h"
+#include "GrResourceCache.h"
 
 /*  Fill out buffer with the compressed format Ganesh expects from a colortable
  based bitmap. [palette (colortable) + indices].
 
  At the moment Ganesh only supports 8bit version. If Ganesh allowed we others
  we could detect that the colortable.count is <= 16, and then repack the
  indices as nibbles to save RAM, but it would take more time (i.e. a lot
  slower than memcpy), so skipping that for now.
 
  Ganesh wants a full 256 palette entry, even though Skia's ctable is only as big
@@ skipping 59 matching lines @@
 }
 
 static void generate_bitmap_texture_desc(const SkBitmap& bitmap, GrTextureDesc* desc) {
     desc->fFlags = kNone_GrTextureFlags;
     desc->fWidth = bitmap.width();
     desc->fHeight = bitmap.height();
     desc->fConfig = SkBitmapConfig2GrPixelConfig(bitmap.config());
     desc->fSampleCnt = 0;
 }
 
+namespace {
+
+// When the SkPixelRef genID changes, invalidate a corresponding GrResource described by key.
+class GrResourceInvalidator : public SkPixelRef::GenIDChangeListener {
+public:
+    explicit GrResourceInvalidator(GrResourceKey key) : fKey(key) {}
+private:
+    GrResourceKey fKey;
+
+    virtual void onChange() SK_OVERRIDE {
+        const GrResourceInvalidatedMessage message = { fKey };
+        SkMessageBus<GrResourceInvalidatedMessage>::Post(message);
+    }
+};
+
+}  // namespace
+
+static void add_genID_listener(GrResourceKey key, SkPixelRef* pixelRef) {
+    SkASSERT(NULL != pixelRef);
+    pixelRef->addGenIDChangeListener(SkNEW_ARGS(GrResourceInvalidator, (key)));
+}
+
 static GrTexture* sk_gr_create_bitmap_texture(GrContext* ctx,
                                               bool cache,
                                               const GrTextureParams* params,
                                               const SkBitmap& origBitmap) {
     SkBitmap tmpBitmap;
 
     const SkBitmap* bitmap = &origBitmap;
 
     GrTextureDesc desc;
     generate_bitmap_texture_desc(*bitmap, &desc);
 
     if (SkBitmap::kIndex8_Config == bitmap->config()) {
         // build_compressed_data doesn't do npot->pot expansion
         // and paletted textures can't be sub-updated
         if (ctx->supportsIndex8PixelConfig(params, bitmap->width(), bitmap->height())) {
             size_t imagesize = bitmap->width() * bitmap->height() + kGrColorTableSize;
             SkAutoMalloc storage(imagesize);
 
             build_compressed_data(storage.get(), origBitmap);
 
             // our compressed data will be trimmed, so pass width() for its
             // "rowBytes", since they are the same now.
 
             if (cache) {
                 GrCacheID cacheID;
                 generate_bitmap_cache_id(origBitmap, &cacheID);
-                return ctx->createTexture(params, desc, cacheID, storage.get(), bitmap->width());
+
+                GrResourceKey key;
+                GrTexture* result = ctx->createTexture(params, desc, cacheID,
+                                                       storage.get(), bitmap->width(), &key);
+                add_genID_listener(key, origBitmap.pixelRef());
+                return result;
             } else {
                 GrTexture* result = ctx->lockAndRefScratchTexture(desc,
                                                             GrContext::kExact_ScratchTexMatch);
                 result->writePixels(0, 0, bitmap->width(),
                                     bitmap->height(), desc.fConfig,
                                     storage.get());
                 return result;
             }
         } else {
             origBitmap.copyTo(&tmpBitmap, SkBitmap::kARGB_8888_Config);
             // now bitmap points to our temp, which has been promoted to 32bits
             bitmap = &tmpBitmap;
             desc.fConfig = SkBitmapConfig2GrPixelConfig(bitmap->config());
         }
     }
 
     SkAutoLockPixels alp(*bitmap);
     if (!bitmap->readyToDraw()) {
         return NULL;
     }
     if (cache) {
         // This texture is likely to be used again so leave it in the cache
         GrCacheID cacheID;
         generate_bitmap_cache_id(origBitmap, &cacheID);
-        return ctx->createTexture(params, desc, cacheID, bitmap->getPixels(), bitmap->rowBytes());
-    } else {
+
+        GrResourceKey key;
+        GrTexture* result = ctx->createTexture(params, desc, cacheID,
+                                               bitmap->getPixels(), bitmap->rowBytes(), &key);
+        add_genID_listener(key, origBitmap.pixelRef());
+        return result;
+   } else {
         // This texture is unlikely to be used again (in its present form) so
         // just use a scratch texture. This will remove the texture from the
         // cache so no one else can find it. Additionally, once unlocked, the
         // scratch texture will go to the end of the list for purging so will
         // likely be available for this volatile bitmap the next time around.
         GrTexture* result = ctx->lockAndRefScratchTexture(desc, GrContext::kExact_ScratchTexMatch);
         result->writePixels(0, 0,
                             bitmap->width(), bitmap->height(),
                             desc.fConfig,
                             bitmap->getPixels(),
@@ skipping 60 matching lines @@
             return kRGB_565_GrPixelConfig;
         case SkBitmap::kARGB_4444_Config:
             return kRGBA_4444_GrPixelConfig;
         case SkBitmap::kARGB_8888_Config:
             return kSkia8888_GrPixelConfig;
         default:
             // kNo_Config, kA1_Config missing
             return kUnknown_GrPixelConfig;
     }
 }