Experimental CompressibleString UMA

third_party/WebKit/Source/bindings/core/v8/V8ValueCache.h

Index: third_party/WebKit/Source/bindings/core/v8/V8ValueCache.h
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8ValueCache.h b/third_party/WebKit/Source/bindings/core/v8/V8ValueCache.h
index 3bc2e00a289657813f6d9724aad46ce8651f8fc3..d7f26a6bf3718bb51aaaa4505f152dcf44a98bd6 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8ValueCache.h
+++ b/third_party/WebKit/Source/bindings/core/v8/V8ValueCache.h
@@ -28,6 +28,7 @@
 
 #include "bindings/core/v8/V8GlobalValueMap.h"
 #include "core/CoreExport.h"
+#include "platform/text/CompressibleString.h"
 #include "wtf/Allocator.h"
 #include "wtf/HashMap.h"
 #include "wtf/Noncopyable.h"
@@ -64,21 +65,57 @@ public:
     static void DisposeWeak(const v8::WeakCallbackInfo<WeakCallbackDataType>&);
 };
 
+class CompressibleStringCacheMapTraits : public V8GlobalValueMapTraits<CompressibleStringImpl*, v8::String, v8::kWeakWithParameter> {
+    STATIC_ONLY(CompressibleStringCacheMapTraits);
+public:
+    // Weak traits:
+    typedef CompressibleStringImpl WeakCallbackDataType;
+    typedef v8::GlobalValueMap<CompressibleStringImpl*, v8::String, CompressibleStringCacheMapTraits> MapType;
+
+    static WeakCallbackDataType* WeakCallbackParameter(
+        MapType* map, CompressibleStringImpl* key, v8::Local<v8::String>& value) { return key; }
+    static void DisposeCallbackData(WeakCallbackDataType* callbackData) { }
+
+    static MapType* MapFromWeakCallbackInfo(
+        const v8::WeakCallbackInfo<WeakCallbackDataType>&);
+
+    static CompressibleStringImpl* KeyFromWeakCallbackInfo(
+        const v8::WeakCallbackInfo<WeakCallbackDataType>& data)
+    {
+        return data.GetParameter();
+    }
+
+    static void OnWeakCallback(const v8::WeakCallbackInfo<WeakCallbackDataType>&);
+
+    static void Dispose(v8::Isolate*, v8::Global<v8::String> value, CompressibleStringImpl* key);
+    static void DisposeWeak(const v8::WeakCallbackInfo<WeakCallbackDataType>&);
+};
 
 class CORE_EXPORT StringCache {
     USING_FAST_MALLOC(StringCache);
     WTF_MAKE_NONCOPYABLE(StringCache);
 public:
-    explicit StringCache(v8::Isolate* isolate) : m_stringCache(isolate) { }
+    explicit StringCache(v8::Isolate* isolate)
+        : m_stringCache(isolate)
+        , m_compressibleStringCache(isolate)
+    {
+    }
 
     v8::Local<v8::String> v8ExternalString(v8::Isolate* isolate, StringImpl* stringImpl)
     {
+        // Note that the last CompressibleString is not cached.

[haraken, 2016/01/15 12:46:21]

This comment should be moved to the below v8ExternalString.

[hajimehoshi, 2016/01/18 09:42:26]

Done.

         ASSERT(stringImpl);
         if (m_lastStringImpl.get() == stringImpl)
             return m_lastV8String.NewLocal(isolate);
         return v8ExternalStringSlow(isolate, stringImpl);
     }
 
+    v8::Local<v8::String> v8ExternalString(v8::Isolate* isolate, const CompressibleString& string)
+    {
+        ASSERT(!string.isNull());

[haraken, 2016/01/15 12:46:21]

Add:

  ASSERT(m_lastStringImpl.get() != string.impl());

[hajimehoshi, 2016/01/18 09:42:26]

string.impl() is CompressibleStringImpl* and I think exposure of
CompressibleStringImpl here is not good.

+        return v8ExternalStringSlow(isolate, string);
+    }
+
     void setReturnValueFromString(v8::ReturnValue<v8::Value> returnValue, StringImpl* stringImpl)
     {
         ASSERT(stringImpl);
@@ -91,16 +128,21 @@ public:
     void dispose();
 
     friend class StringCacheMapTraits;
+    friend class CompressibleStringCacheMapTraits;
 
 private:
     v8::Local<v8::String> v8ExternalStringSlow(v8::Isolate*, StringImpl*);
+    v8::Local<v8::String> v8ExternalStringSlow(v8::Isolate*, const CompressibleString&);
     void setReturnValueFromStringSlow(v8::ReturnValue<v8::Value>, StringImpl*);
     v8::Local<v8::String> createStringAndInsertIntoCache(v8::Isolate*, StringImpl*);
+    v8::Local<v8::String> createStringAndInsertIntoCache(v8::Isolate*, const CompressibleString&);
     void InvalidateLastString();
 
     StringCacheMapTraits::MapType m_stringCache;
     StringCacheMapTraits::MapType::PersistentValueReference m_lastV8String;
 
+    CompressibleStringCacheMapTraits::MapType m_compressibleStringCache;
+
     // Note: RefPtr is a must as we cache by StringImpl* equality, not identity
     // hence lastStringImpl might be not a key of the cache (in sense of identity)
     // and hence it's not refed on addition.