Revert of Implement SkImageFilter::Cache with SkResourceCache.

src/core/SkImageFilter.cpp

Index: src/core/SkImageFilter.cpp
diff --git a/src/core/SkImageFilter.cpp b/src/core/SkImageFilter.cpp
index 6c4561b0646958e92d110989374af3d5fd5e45a3..ffb1f836d890ef1b1cad7a520d7857e1b75411c5 100644
--- a/src/core/SkImageFilter.cpp
+++ b/src/core/SkImageFilter.cpp
@@ -14,10 +14,8 @@
 #include "SkMatrixImageFilter.h"
 #include "SkMutex.h"
 #include "SkOncePtr.h"
-#include "SkPixelRef.h"
 #include "SkReadBuffer.h"
 #include "SkRect.h"
-#include "SkResourceCache.h"
 #include "SkTDynamicHash.h"
 #include "SkTInternalLList.h"
 #include "SkValidationUtils.h"
@@ -27,6 +25,12 @@
 #include "GrDrawContext.h"
 #include "SkGrPixelRef.h"
 #include "SkGr.h"
+#endif
+
+#ifdef SK_BUILD_FOR_IOS
+  enum { kDefaultCacheSize = 2 * 1024 * 1024 };
+#else
+  enum { kDefaultCacheSize = 128 * 1024 * 1024 };
 #endif
 
 #ifndef SK_IGNORE_TO_STRING
@@ -473,122 +477,102 @@
 
 namespace {
 
-class ImageFilterRec : public SkResourceCache::Rec {
+class CacheImpl : public SkImageFilter::Cache {
 public:
-    struct Keys {
-        Keys(SkImageFilter::Cache::Key ifcKey) : fIFCKey(ifcKey) {
-            static bool unique_namespace;
-            fRCKey.init(&unique_namespace,
-                        0 /*shared ids allow fine-grained purging, which we can't use here*/,
-                        sizeof(fIFCKey));
-        }
-        // The SkImageFilter::Cache::Key must immediately follow the SkResourceCache::Key.
-        SkResourceCache::Key            fRCKey;
-        const SkImageFilter::Cache::Key fIFCKey;
+    CacheImpl(size_t maxBytes) : fMaxBytes(maxBytes), fCurrentBytes(0) {
+    }
+    virtual ~CacheImpl() {
+        SkTDynamicHash<Value, Key>::Iter iter(&fLookup);
+
+        while (!iter.done()) {
+            Value* v = &*iter;
+            ++iter;
+            delete v;
+        }
+    }
+    struct Value {
+        Value(const Key& key, const SkBitmap& bitmap, const SkIPoint& offset)
+            : fKey(key), fBitmap(bitmap), fOffset(offset) {}
+        Key fKey;
+        SkBitmap fBitmap;
+        SkIPoint fOffset;
+        static const Key& GetKey(const Value& v) {
+            return v.fKey;
+        }
+        static uint32_t Hash(const Key& key) {
+            return SkChecksum::Murmur3(reinterpret_cast<const uint32_t*>(&key), sizeof(Key));
+        }
+        SK_DECLARE_INTERNAL_LLIST_INTERFACE(Value);
     };
-
-    ImageFilterRec(SkImageFilter::Cache::Key ifcKey, const SkBitmap& bm, const SkIPoint& offset)
-        : fKeys(ifcKey)
-        , fBitmap(bm)
-        , fOffset(offset) {}
-
-    const Key& getKey() const override { return fKeys.fRCKey; }
-    size_t bytesUsed() const override { return sizeof(*this) + fBitmap.getSize(); }
-    const char* getCategory() const override { return "SkImageFilter::Cache"; }
-
-    SkDiscardableMemory* diagnostic_only_getDiscardable() const override {
-        if (auto pr = fBitmap.pixelRef()) {
-            return pr->diagnostic_only_getDiscardable();
-        }
-        return nullptr;
-    }
-
-    const SkBitmap& bitmap() const { return fBitmap; }
-    const SkIPoint& offset() const { return fOffset; }
+    bool get(const Key& key, SkBitmap* result, SkIPoint* offset) const override {
+        SkAutoMutexAcquire mutex(fMutex);
+        if (Value* v = fLookup.find(key)) {
+            *result = v->fBitmap;
+            *offset = v->fOffset;
+            if (v != fLRU.head()) {
+                fLRU.remove(v);
+                fLRU.addToHead(v);
+            }
+            return true;
+        }
+        return false;
+    }
+    void set(const Key& key, const SkBitmap& result, const SkIPoint& offset) override {
+        SkAutoMutexAcquire mutex(fMutex);
+        if (Value* v = fLookup.find(key)) {
+            removeInternal(v);
+        }
+        Value* v = new Value(key, result, offset);
+        fLookup.add(v);
+        fLRU.addToHead(v);
+        fCurrentBytes += result.getSize();
+        while (fCurrentBytes > fMaxBytes) {
+            Value* tail = fLRU.tail();
+            SkASSERT(tail);
+            if (tail == v) {
+                break;
+            }
+            removeInternal(tail);
+        }
+    }
+
+    void purge() override {
+        SkAutoMutexAcquire mutex(fMutex);
+        while (fCurrentBytes > 0) {
+            Value* tail = fLRU.tail();
+            SkASSERT(tail);
+            this->removeInternal(tail);
+        }
+    }
 
 private:
-    const Keys      fKeys;
-    const SkBitmap  fBitmap;
-    const SkIPoint  fOffset;
+    void removeInternal(Value* v) {
+        fCurrentBytes -= v->fBitmap.getSize();
+        fLRU.remove(v);
+        fLookup.remove(v->fKey);
+        delete v;
+    }
+private:
+    SkTDynamicHash<Value, Key>         fLookup;
+    mutable SkTInternalLList<Value>    fLRU;
+    size_t                             fMaxBytes;
+    size_t                             fCurrentBytes;
+    mutable SkMutex                    fMutex;
 };
 
-struct GetVisitor {
-    SkBitmap* fResult;
-    SkIPoint* fOffset;
-
-    static bool Visit(const SkResourceCache::Rec& rec, void* context) {
-        auto r = (const ImageFilterRec&)rec;
-        auto c = (GetVisitor*)context;
-        *c->fResult = r.bitmap();
-        *c->fOffset = r.offset();
-        return true;
-    }
-};
-
-// Thread-safe SkImageFilter::Cache that uses the global SkResourceCache.
-class GlobalCache : public SkImageFilter::Cache {
-public:
-    GlobalCache() {}
-
-    void set(const Key& key, const SkBitmap& result, const SkIPoint& offset) override {
-        const SkBitmap* bm = &result;
-        SkBitmap copy;
-        // Image filters allocate their own result bitmaps.
-        // If we're putting a bitmap into the SkResourceCache backed by discardable memory,
-        // we'd better make sure those bitmaps are discardable too (and vice versa).
-        // The expected case in Chrome is: rcIsDiscardable == true, bmIsDiscardable == false.
-        auto allocator = SkResourceCache::GetAllocator();
-#if 0
-        bool rcIsDiscardable = allocator,
-             bmIsDiscardable = bm->pixelRef() && bm->pixelRef()->diagnostic_only_getDiscardable();
-        if (rcIsDiscardable != bmIsDiscardable) {
-#else
-        {
-#endif
-            bm->copyTo(&copy, allocator);
-            bm = &copy;
-        }
-        SkResourceCache::Add(new ImageFilterRec(key, *bm, offset));
-    }
-
-    bool get(const Key& ifcKey, SkBitmap* result, SkIPoint* offset) const override {
-        const ImageFilterRec::Keys keys(ifcKey);
-        GetVisitor visitor { result, offset };
-        return SkResourceCache::Find(keys.fRCKey, GetVisitor::Visit, &visitor);
-    }
-};
-
-// Non-thread-safe siloed SkImageFilter::Cache, meant to be small and ephemeral.
-class LocalCache : public SkImageFilter::Cache {
-public:
-    LocalCache(size_t maxBytes) : fRC(maxBytes) {
-        SkASSERT(fRC.allocator() == nullptr);
-    }
-
-    void set(const Key& key, const SkBitmap& result, const SkIPoint& offset) override {
-        SkASSERT(result.pixelRef() == nullptr ||
-                 result.pixelRef()->diagnostic_only_getDiscardable() == nullptr);
-        fRC.add(new ImageFilterRec(key, result, offset));
-    }
-
-    bool get(const Key& ifcKey, SkBitmap* result, SkIPoint* offset) const override {
-        const ImageFilterRec::Keys keys(ifcKey);
-        GetVisitor visitor { result, offset };
-        return fRC.find(keys.fRCKey, GetVisitor::Visit, &visitor);
-    }
-private:
-    mutable SkResourceCache fRC;  // SkResourceCache::find() is not const (updates LRU).
-};
-
 } // namespace
 
 SkImageFilter::Cache* SkImageFilter::Cache::Create(size_t maxBytes) {
-    return new LocalCache(maxBytes);
+    return new CacheImpl(maxBytes);
 }
 
 SK_DECLARE_STATIC_ONCE_PTR(SkImageFilter::Cache, cache);
 SkImageFilter::Cache* SkImageFilter::Cache::Get() {
-    return cache.get([]{ return new GlobalCache; });
+    return cache.get([]{ return SkImageFilter::Cache::Create(kDefaultCacheSize); });
+}
+
+void SkImageFilter::PurgeCache() {
+    Cache::Get()->purge();
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////