Revert of Implement SkImageFilter::Cache with SkResourceCache. (patchset #8 id:140001 of https://codereview.chromium.org/1370323002/ )

Reason for revert:
Landed PS8 temporarily to trigger the perf bots.

Original issue's description:
> Implement SkImageFilter::Cache with SkResourceCache.
>
> The single global cache now uses the global SkResourceCache,
> and any Create()ed cache uses a local SkResourceCache.
>
> No real public API changes (and only deletes).
>
> I don't see any pixel diffs on .skps or GMs.
> Don't see any significant perf difference on 8888 or gpu configs.
> DM peak memory usage did drop by about 113M, close to the 128M cache size.
>
> BUG=skia:3662
>
> Landing PS8 temporarily to trigger the perf bots.
> TBR=reed@google.com
>
> Committed: https://skia.googlesource.com/skia/+/75135d8ae1aa12e8e6bfce63291e5e876a77546f

TBR=reed@google.com,robertphillips@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:3662

Review URL: https://codereview.chromium.org/1381523002

2 files changed, 81 insertions, 96 deletions

diff --git a/src/core/SkImageFilter.cpp b/src/core/SkImageFilter.cpp
index 6c4561b064..ffb1f836d8 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"
@@ -29,6 +27,12 @@
 #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
 void SkImageFilter::CropRect::toString(SkString* str) const {
     if (!fFlags) {
@@ -473,122 +477,102 @@ bool SkImageFilter::getInputResultGPU(SkImageFilter::Proxy* proxy,
 
 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;
-    };
-
-    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"; }
+    CacheImpl(size_t maxBytes) : fMaxBytes(maxBytes), fCurrentBytes(0) {
+    }
+    virtual ~CacheImpl() {
+        SkTDynamicHash<Value, Key>::Iter iter(&fLookup);
 
-    SkDiscardableMemory* diagnostic_only_getDiscardable() const override {
-        if (auto pr = fBitmap.pixelRef()) {
-            return pr->diagnostic_only_getDiscardable();
+        while (!iter.done()) {
+            Value* v = &*iter;
+            ++iter;
+            delete v;
         }
-        return nullptr;
     }
-
-    const SkBitmap& bitmap() const { return fBitmap; }
-    const SkIPoint& offset() const { return fOffset; }
-
-private:
-    const Keys      fKeys;
-    const SkBitmap  fBitmap;
-    const SkIPoint  fOffset;
-};
-
-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;
+    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);
+    };
+    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;
     }
-};
-
-// 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;
+        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);
         }
-        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));
+    void purge() override {
+        SkAutoMutexAcquire mutex(fMutex);
+        while (fCurrentBytes > 0) {
+            Value* tail = fLRU.tail();
+            SkASSERT(tail);
+            this->removeInternal(tail);
+        }
     }
 
-    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:
+    void removeInternal(Value* v) {
+        fCurrentBytes -= v->fBitmap.getSize();
+        fLRU.remove(v);
+        fLookup.remove(v->fKey);
+        delete v;
     }
 private:
-    mutable SkResourceCache fRC;  // SkResourceCache::find() is not const (updates LRU).
+    SkTDynamicHash<Value, Key>         fLookup;
+    mutable SkTInternalLList<Value>    fLRU;
+    size_t                             fMaxBytes;
+    size_t                             fCurrentBytes;
+    mutable SkMutex                    fMutex;
 };
 
 } // 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();
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
diff --git a/src/core/SkResourceCache.cpp b/src/core/SkResourceCache.cpp
index a79c9539b9..54091f1fd4 100644
--- a/src/core/SkResourceCache.cpp
+++ b/src/core/SkResourceCache.cpp
@@ -658,6 +658,7 @@ size_t SkGraphics::SetResourceCacheSingleAllocationByteLimit(size_t newLimit) {
 }
 
 void SkGraphics::PurgeResourceCache() {
+    SkImageFilter::PurgeCache();
     return SkResourceCache::PurgeAll();
 }