Trying to add the same scaled image twice shouldn't assert.

This unbreaks bench_pictures --multi foo for me.

BUG=skia:1868
R=reed@google.com

Author: mtklein@google.com

Review URL: https://codereview.chromium.org/89293002

git-svn-id: http://skia.googlecode.com/svn/trunk@12422 2bbb7eff-a529-9590-31e7-b0007b416f81

3 files changed, 51 insertions, 19 deletions

diff --git a/src/core/SkScaledImageCache.cpp b/src/core/SkScaledImageCache.cpp
index ea29843c92..55eadb849e 100644
--- a/src/core/SkScaledImageCache.cpp
+++ b/src/core/SkScaledImageCache.cpp
@@ -49,7 +49,7 @@ static uint32_t compute_hash(const uint32_t data[], int count) {
     return hash;
 }
 
-struct Key {
+struct SkScaledImageCache::Key {
     Key(uint32_t genID,
         SkScalar scaleX,
         SkScalar scaleY,
@@ -129,22 +129,24 @@ struct SkScaledImageCache::Rec {
 #include "SkTDynamicHash.h"
 
 namespace { // can't use static functions w/ template parameters
-const Key& key_from_rec(const SkScaledImageCache::Rec& rec) {
+const SkScaledImageCache::Key& key_from_rec(const SkScaledImageCache::Rec& rec) {
     return rec.fKey;
 }
 
-uint32_t hash_from_key(const Key& key) {
+uint32_t hash_from_key(const SkScaledImageCache::Key& key) {
     return key.fHash;
 }
 
-bool eq_rec_key(const SkScaledImageCache::Rec& rec, const Key& key) {
+bool eq_rec_key(const SkScaledImageCache::Rec& rec, const SkScaledImageCache::Key& key) {
     return rec.fKey == key;
 }
 }
 
 class SkScaledImageCache::Hash : public SkTDynamicHash<SkScaledImageCache::Rec,
-                                   Key, key_from_rec, hash_from_key,
-                                   eq_rec_key> {};
+                                                       SkScaledImageCache::Key,
+                                                       key_from_rec,
+                                                       hash_from_key,
+                                                       eq_rec_key> {};
 
 ///////////////////////////////////////////////////////////////////////////////
 
@@ -187,17 +189,22 @@ SkScaledImageCache::~SkScaledImageCache() {
 
 ////////////////////////////////////////////////////////////////////////////////
 
-/**
-   This private method is the fully general record finder. All other
-   record finders should call this funtion. */
+
 SkScaledImageCache::Rec* SkScaledImageCache::findAndLock(uint32_t genID,
                                                         SkScalar scaleX,
                                                         SkScalar scaleY,
                                                         const SkIRect& bounds) {
-    if (bounds.isEmpty()) {
+    const Key key(genID, scaleX, scaleY, bounds);
+    return this->findAndLock(key);
+}
+
+/**
+   This private method is the fully general record finder. All other
+   record finders should call this function or the one above. */
+SkScaledImageCache::Rec* SkScaledImageCache::findAndLock(const SkScaledImageCache::Key& key) {
+    if (key.fBounds.isEmpty()) {
         return NULL;
     }
-    Key key(genID, scaleX, scaleY, bounds);
 #ifdef USE_HASH
     Rec* rec = fHash->find(key);
 #else
@@ -275,8 +282,14 @@ SkScaledImageCache::ID* SkScaledImageCache::findAndLockMip(const SkBitmap& orig,
 /**
    This private method is the fully general record adder. All other
    record adders should call this funtion. */
-void SkScaledImageCache::addAndLock(SkScaledImageCache::Rec* rec) {
+SkScaledImageCache::ID* SkScaledImageCache::addAndLock(SkScaledImageCache::Rec* rec) {
     SkASSERT(rec);
+    // See if we already have this key (racy inserts, etc.)
+    Rec* existing = this->findAndLock(rec->fKey);
+    if (existing != NULL) {
+        return rec_to_id(existing);
+    }
+
     this->addToHead(rec);
     SkASSERT(1 == rec->fLockCount);
 #ifdef USE_HASH
@@ -285,6 +298,7 @@ void SkScaledImageCache::addAndLock(SkScaledImageCache::Rec* rec) {
 #endif
     // We may (now) be overbudget, so see if we need to purge something.
     this->purgeAsNeeded();
+    return rec_to_id(rec);
 }
 
 SkScaledImageCache::ID* SkScaledImageCache::addAndLock(uint32_t genID,
@@ -293,8 +307,7 @@ SkScaledImageCache::ID* SkScaledImageCache::addAndLock(uint32_t genID,
                                                        const SkBitmap& bitmap) {
     Key key(genID, SK_Scalar1, SK_Scalar1, SkIRect::MakeWH(width, height));
     Rec* rec = SkNEW_ARGS(Rec, (key, bitmap));
-    this->addAndLock(rec);
-    return rec_to_id(rec);
+    return this->addAndLock(rec);
 }
 
 SkScaledImageCache::ID* SkScaledImageCache::addAndLock(const SkBitmap& orig,
@@ -311,8 +324,7 @@ SkScaledImageCache::ID* SkScaledImageCache::addAndLock(const SkBitmap& orig,
     }
     Key key(orig.getGenerationID(), scaleX, scaleY, bounds);
     Rec* rec = SkNEW_ARGS(Rec, (key, scaled));
-    this->addAndLock(rec);
-    return rec_to_id(rec);
+    return this->addAndLock(rec);
 }
 
 SkScaledImageCache::ID* SkScaledImageCache::addAndLockMip(const SkBitmap& orig,
@@ -323,8 +335,7 @@ SkScaledImageCache::ID* SkScaledImageCache::addAndLockMip(const SkBitmap& orig,
     }
     Key key(orig.getGenerationID(), 0, 0, bounds);
     Rec* rec = SkNEW_ARGS(Rec, (key, mip));
-    this->addAndLock(rec);
-    return rec_to_id(rec);
+    return this->addAndLock(rec);
 }
 
 void SkScaledImageCache::unlock(SkScaledImageCache::ID* id) {
diff --git a/src/core/SkScaledImageCache.h b/src/core/SkScaledImageCache.h
index fee69d2d58..44ef1f8a2c 100644
--- a/src/core/SkScaledImageCache.h
+++ b/src/core/SkScaledImageCache.h
@@ -126,6 +126,7 @@ public:
 
 public:
     struct Rec;
+    struct Key;
 private:
     Rec*    fHead;
     Rec*    fTail;
@@ -139,7 +140,8 @@ private:
 
     Rec* findAndLock(uint32_t generationID, SkScalar sx, SkScalar sy,
                      const SkIRect& bounds);
-    void addAndLock(Rec* rec);
+    Rec* findAndLock(const Key& key);
+    ID* addAndLock(Rec* rec);
 
     void purgeAsNeeded();
 
diff --git a/tests/ImageCacheTest.cpp b/tests/ImageCacheTest.cpp
index 877591acc7..b8815a3217 100644
--- a/tests/ImageCacheTest.cpp
+++ b/tests/ImageCacheTest.cpp
@@ -63,3 +63,22 @@ static void TestImageCache(skiatest::Reporter* reporter) {
 
 #include "TestClassDef.h"
 DEFINE_TESTCLASS("ImageCache", TestImageCacheClass, TestImageCache)
+
+DEF_TEST(ImageCache_doubleAdd, r) {
+    // Adding the same key twice should be safe.
+    SkScaledImageCache cache(1024);
+
+    SkBitmap original;
+    original.setConfig(SkBitmap::kARGB_8888_Config, 40, 40);
+    original.allocPixels();
+
+    SkBitmap scaled;
+    scaled.setConfig(SkBitmap::kARGB_8888_Config, 20, 20);
+    scaled.allocPixels();
+
+    SkScaledImageCache::ID* id1 = cache.addAndLock(original, 0.5f, 0.5f, scaled);
+    SkScaledImageCache::ID* id2 = cache.addAndLock(original, 0.5f, 0.5f, scaled);
+    // We don't really care if id1 == id2 as long as unlocking both works.
+    cache.unlock(id1);
+    cache.unlock(id2);
+}