Notify resource caches when pixelref genID goes stale

patch from issue 954443002 at patchset 40001 (http://crrev.com/954443002#ps40001)

BUG=skia:

Review URL: https://codereview.chromium.org/950363002

2 files changed, 102 insertions, 2 deletions

diff --git a/tests/ImageCacheTest.cpp b/tests/ImageCacheTest.cpp
index a4cfa73989..45dee92a2f 100644
--- a/tests/ImageCacheTest.cpp
+++ b/tests/ImageCacheTest.cpp
@@ -14,8 +14,8 @@ 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 {
@@ -71,6 +71,38 @@ static void test_cache(skiatest::Reporter* reporter, SkResourceCache& cache, boo
     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;
@@ -97,6 +129,10 @@ DEF_TEST(ImageCache, reporter) {
         SkResourceCache cache(SkDiscardableMemory::Create);
         test_cache(reporter, cache, false);
     }
+    {
+        SkResourceCache cache(defLimit);
+        test_cache_purge_shared_id(reporter, cache);
+    }
 }
 
 DEF_TEST(ImageCache_doubleAdd, r) {
diff --git a/tests/SkResourceCacheTest.cpp b/tests/SkResourceCacheTest.cpp
index 179e771ed8..626c837361 100644
--- a/tests/SkResourceCacheTest.cpp
+++ b/tests/SkResourceCacheTest.cpp
@@ -156,6 +156,14 @@ static void test_mipmapcache(skiatest::Reporter* reporter, SkResourceCache* cach
 
     mipmap = SkMipMapCache::AddAndRef(src, cache);
     REPORTER_ASSERT(reporter, mipmap);
+
+    {
+        const SkMipMap* mm = SkMipMapCache::FindAndRef(src, cache);
+        REPORTER_ASSERT(reporter, mm);
+        REPORTER_ASSERT(reporter, mm == mipmap);
+        mm->unref();
+    }
+
     check_data(reporter, mipmap, 2, kInCache, kLocked);
 
     mipmap->unref();
@@ -173,6 +181,60 @@ static void test_mipmapcache(skiatest::Reporter* reporter, SkResourceCache* cach
     mipmap->unref();
 }
 
+static void test_mipmap_notify(skiatest::Reporter* reporter, SkResourceCache* cache) {
+    const int N = 3;
+    SkBitmap src[N];
+    for (int i = 0; i < N; ++i) {
+        src[i].allocN32Pixels(5, 5);
+        src[i].setImmutable();
+        SkMipMapCache::AddAndRef(src[i], cache)->unref();
+    }
+
+    for (int i = 0; i < N; ++i) {
+        const SkMipMap* mipmap = SkMipMapCache::FindAndRef(src[i], cache);
+        if (cache) {
+            // if cache is null, we're working on the global cache, and other threads might purge
+            // it, making this check fragile.
+            REPORTER_ASSERT(reporter, mipmap);
+        }
+        SkSafeUnref(mipmap);
+
+        src[i].reset(); // delete the underlying pixelref, which *should* remove us from the cache
+
+        mipmap = SkMipMapCache::FindAndRef(src[i], cache);
+        REPORTER_ASSERT(reporter, !mipmap);
+    }
+}
+
+static void test_bitmap_notify(skiatest::Reporter* reporter, SkResourceCache* cache) {
+    const SkIRect subset = SkIRect::MakeWH(5, 5);
+    const int N = 3;
+    SkBitmap src[N], dst[N];
+    for (int i = 0; i < N; ++i) {
+        src[i].allocN32Pixels(5, 5);
+        src[i].setImmutable();
+        dst[i].allocN32Pixels(5, 5);
+        dst[i].setImmutable();
+        SkBitmapCache::Add(src[i].getGenerationID(), subset, dst[i], cache);
+    }
+
+    for (int i = 0; i < N; ++i) {
+        const uint32_t genID = src[i].getGenerationID();
+        SkBitmap result;
+        bool found = SkBitmapCache::Find(genID, subset, &result, cache);
+        if (cache) {
+            // if cache is null, we're working on the global cache, and other threads might purge
+            // it, making this check fragile.
+            REPORTER_ASSERT(reporter, found);
+        }
+
+        src[i].reset(); // delete the underlying pixelref, which *should* remove us from the cache
+
+        found = SkBitmapCache::Find(genID, subset, &result, cache);
+        REPORTER_ASSERT(reporter, !found);
+    }
+}
+
 DEF_TEST(BitmapCache_discarded_bitmap, reporter) {
     SkResourceCache::DiscardableFactory factory = SkResourceCache::GetDiscardableFactory();
     SkBitmap::Allocator* allocator = SkBitmapCache::GetAllocator();
@@ -219,4 +281,6 @@ DEF_TEST(BitmapCache_discarded_bitmap, reporter) {
     REPORTER_ASSERT(reporter, SkBitmapCache::Find(cachedBitmap.getGenerationID(), rect, &bm, cache));
 
     test_mipmapcache(reporter, cache);
+    test_bitmap_notify(reporter, cache);
+    test_mipmap_notify(reporter, cache);
 }