Add auto purging for SkPicture-related Ganesh resources (esp. layers)

tests/GpuLayerCacheTest.cpp

 /*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #if SK_SUPPORT_GPU
 
 #include "GrContext.h"
 #include "GrContextFactory.h"
 #include "GrLayerCache.h"
 #include "SkPictureRecorder.h"
 #include "Test.h"
 
 static const int kNumLayers = 5;
 
-class GetNumLayers {
+class TestingAccess {
 public:
     static int NumLayers(GrLayerCache* cache) {
         return cache->numLayers();
     }
+    static void Purge(GrLayerCache* cache, uint32_t pictureID) {
+        cache->purge(pictureID);
+    }
 };
 
 // Add several layers to the cache
 static void create_layers(skiatest::Reporter* reporter,
                           GrLayerCache* cache,
                           const SkPicture& picture) {
     GrCachedLayer* layers[kNumLayers];
 
     for (int i = 0; i < kNumLayers; ++i) {
         layers[i] = cache->findLayerOrCreate(&picture, i);
         REPORTER_ASSERT(reporter, NULL != layers[i]);
         GrCachedLayer* layer = cache->findLayer(&picture, i);
         REPORTER_ASSERT(reporter, layer == layers[i]);
 
-        REPORTER_ASSERT(reporter, GetNumLayers::NumLayers(cache) == i+1);
+        REPORTER_ASSERT(reporter, TestingAccess::NumLayers(cache) == i + 1);
 
         REPORTER_ASSERT(reporter, picture.uniqueID() == layers[i]->pictureID());
         REPORTER_ASSERT(reporter, layers[i]->layerID() == i);
         REPORTER_ASSERT(reporter, NULL == layers[i]->texture());
         REPORTER_ASSERT(reporter, !layers[i]->isAtlased());
     }
 
+    cache->trackPicture(&picture);
 }
 
 // This test case exercises the public API of the GrLayerCache class.
 // In particular it checks its interaction with the resource cache (w.r.t.
 // locking & unlocking textures).
 // TODO: need to add checks on VRAM usage!
 DEF_GPUTEST(GpuLayerCache, reporter, factory) {
     for (int i= 0; i < GrContextFactory::kGLContextTypeCnt; ++i) {
         GrContextFactory::GLContextType glCtxType = (GrContextFactory::GLContextType) i;
 
@@ skipping 64 matching lines @@
                 REPORTER_ASSERT(reporter, layer->isAtlased());
             } else {
 #endif
                 REPORTER_ASSERT(reporter, NULL == layer->texture());
                 REPORTER_ASSERT(reporter, !layer->isAtlased());
 #if USE_ATLAS
             }
 #endif
         }
 
+        //--------------------------------------------------------------------
         // Free them all SkGpuDevice-style. This will not free up the
         // atlas' texture but will eliminate all the layers.
-        cache.purge(picture);
+        TestingAccess::Purge(&cache, picture->uniqueID());
 
-        REPORTER_ASSERT(reporter, GetNumLayers::NumLayers(&cache) == 0);
+        REPORTER_ASSERT(reporter, TestingAccess::NumLayers(&cache) == 0);
         // TODO: add VRAM/resource cache check here
-#if 0
+
+        //--------------------------------------------------------------------
+        // Test out the GrContext-style purge. This should remove all the layers
+        // and the atlas.
         // Re-create the layers
-        create_layers(reporter, &cache, picture);
+        create_layers(reporter, &cache, *picture);
 
         // Free them again GrContext-style. This should free up everything.
         cache.freeAll();
 
-        REPORTER_ASSERT(reporter, GetNumLayers::NumLayers(&cache) == 0);
+        REPORTER_ASSERT(reporter, TestingAccess::NumLayers(&cache) == 0);
         // TODO: add VRAM/resource cache check here
-#endif
+
+        //--------------------------------------------------------------------
+        // Test out the MessageBus-style purge. This will not free the atlas
+        // but should eliminate the free-floating layers.
+        create_layers(reporter, &cache, *picture);
+
+        picture.reset(NULL);
+        cache.processDeletedPictures();
+
+        REPORTER_ASSERT(reporter, TestingAccess::NumLayers(&cache) == 0);
+        // TODO: add VRAM/resource cache check here
     }
 }
 
 #endif