Notify resource caches when pixelref genID goes stale

tests/ImageCacheTest.cpp

  /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDiscardableMemory.h"
 #include "SkResourceCache.h"
 #include "Test.h"
 
 namespace {
 static void* gGlobalAddress;
 struct TestingKey : public SkResourceCache::Key {
     intptr_t    fValue;
 
-    TestingKey(intptr_t value) : fValue(value) {
-        this->init(&gGlobalAddress, sizeof(fValue));
+    TestingKey(intptr_t value, uint64_t sharedID = 0) : fValue(value) {
+        this->init(&gGlobalAddress, sharedID, sizeof(fValue));
     }
 };
 struct TestingRec : public SkResourceCache::Rec {
     TestingRec(const TestingKey& key, uint32_t value) : fKey(key), fValue(value) {}
 
     TestingKey  fKey;
     intptr_t    fValue;
 
     const Key& getKey() const SK_OVERRIDE { return fKey; }
     size_t bytesUsed() const SK_OVERRIDE { return sizeof(fKey) + sizeof(fValue); }
@@ skipping 35 matching lines @@
 
     // test the originals after all that purging
     for (int i = 0; i < COUNT; ++i) {
         intptr_t value;
         (void)cache.find(TestingKey(i), TestingRec::Visitor, &value);
     }
 
     cache.setTotalByteLimit(0);
 }
 
+static void test_cache_purge_shared_id(skiatest::Reporter* reporter, SkResourceCache& cache) {
+    for (int i = 0; i < COUNT; ++i) {
+        TestingKey key(i, i & 1);   // every other key will have a 1 for its sharedID        
+        cache.add(SkNEW_ARGS(TestingRec, (key, i)));
+    }
+
+    // Ensure that everyone is present
+    for (int i = 0; i < COUNT; ++i) {
+        TestingKey key(i, i & 1);   // every other key will have a 1 for its sharedID
+        intptr_t value = -1;
+
+        REPORTER_ASSERT(reporter, cache.find(key, TestingRec::Visitor, &value));
+        REPORTER_ASSERT(reporter, value == i);
+    }
+
+    // Now purge the ones that had a non-zero sharedID (the odd-indexed ones)
+    cache.purgeSharedID(1);
+
+    // Ensure that only the even ones are still present
+    for (int i = 0; i < COUNT; ++i) {
+        TestingKey key(i, i & 1);   // every other key will have a 1 for its sharedID
+        intptr_t value = -1;
+
+        if (i & 1) {
+            REPORTER_ASSERT(reporter, !cache.find(key, TestingRec::Visitor, &value));
+        } else {
+            REPORTER_ASSERT(reporter, cache.find(key, TestingRec::Visitor, &value));
+            REPORTER_ASSERT(reporter, value == i);
+        }
+    }
+}
+
 #include "SkDiscardableMemoryPool.h"
 
 static SkDiscardableMemoryPool* gPool;
 static SkDiscardableMemory* pool_factory(size_t bytes) {
     SkASSERT(gPool);
     return gPool->create(bytes);
 }
 
 DEF_TEST(ImageCache, reporter) {
     static const size_t defLimit = DIM * DIM * 4 * COUNT + 1024;    // 1K slop
 
     {
         SkResourceCache cache(defLimit);
         test_cache(reporter, cache, true);
     }
     {
         SkAutoTUnref<SkDiscardableMemoryPool> pool(
                 SkDiscardableMemoryPool::Create(defLimit, NULL));
         gPool = pool.get();
         SkResourceCache cache(pool_factory);
         test_cache(reporter, cache, true);
     }
     {
         SkResourceCache cache(SkDiscardableMemory::Create);
         test_cache(reporter, cache, false);
     }
+    {
+        SkResourceCache cache(defLimit);
+        test_cache_purge_shared_id(reporter, cache);
+    }
 }
 
 DEF_TEST(ImageCache_doubleAdd, r) {
     // Adding the same key twice should be safe.
     SkResourceCache cache(4096);
 
     TestingKey key(1);
 
     cache.add(SkNEW_ARGS(TestingRec, (key, 2)));
     cache.add(SkNEW_ARGS(TestingRec, (key, 3)));
 
     // Lookup can return either value.
     intptr_t value = -1;
     REPORTER_ASSERT(r, cache.find(key, TestingRec::Visitor, &value));
     REPORTER_ASSERT(r, 2 == value || 3 == value);
 }