WIP: Introduce CompressibleString

third_party/WebKit/Source/bindings/core/v8/V8StringResource.cpp

Index: third_party/WebKit/Source/bindings/core/v8/V8StringResource.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/V8StringResource.cpp b/third_party/WebKit/Source/bindings/core/v8/V8StringResource.cpp
index 5dc1eb2eaaabab6a37058e59000353c2e0f1ab11..0c00845ae5fad66efaabbc7a1aad355e4a7bc7e4 100644
--- a/third_party/WebKit/Source/bindings/core/v8/V8StringResource.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/V8StringResource.cpp
@@ -39,7 +39,7 @@ template<class StringClass> struct StringTraits {
 
 template<>
 struct StringTraits<String> {
-    static const String& fromStringResource(WebCoreStringResourceBase* resource)
+    static String fromStringResource(WebCoreStringResourceBase* resource)
     {
         return resource->webcoreString();
     }
@@ -49,7 +49,7 @@ struct StringTraits<String> {
 
 template<>
 struct StringTraits<AtomicString> {
-    static const AtomicString& fromStringResource(WebCoreStringResourceBase* resource)
+    static AtomicString fromStringResource(WebCoreStringResourceBase* resource)
     {
         return resource->atomicString();
     }
@@ -108,10 +108,17 @@ StringType v8StringToWebCoreString(v8::Local<v8::String> v8String, ExternalMode
         v8::String::ExternalStringResourceBase* resource = v8String->GetExternalStringResourceBase(&encoding);
         if (LIKELY(!!resource)) {
             WebCoreStringResourceBase* base;
-            if (encoding == v8::String::ONE_BYTE_ENCODING)
-                base = static_cast<WebCoreStringResource8*>(resource);
-            else
-                base = static_cast<WebCoreStringResource16*>(resource);
+            if (UNLIKELY(resource->isCompressable())) {
+                if (encoding == v8::String::ONE_BYTE_ENCODING)
+                    base = static_cast<WebCoreCompressableStringResource8*>(resource);
+                else
+                    base = static_cast<WebCoreCompressableStringResource16*>(resource);
+            } else {
+                if (encoding == v8::String::ONE_BYTE_ENCODING)
+                    base = static_cast<WebCoreStringResource8*>(resource);
+                else
+                    base = static_cast<WebCoreStringResource16*>(resource);
+            }
             return StringTraits<StringType>::fromStringResource(base);
         }
     }
@@ -143,6 +150,48 @@ StringType v8StringToWebCoreString(v8::Local<v8::String> v8String, ExternalMode
 template String v8StringToWebCoreString<String>(v8::Local<v8::String>, ExternalMode);
 template AtomicString v8StringToWebCoreString<AtomicString>(v8::Local<v8::String>, ExternalMode);
 
+template String v8StringToWebCoreString2<String>(v8::Local<v8::String>, ExternalMode);

[haraken, 2015/11/24 11:15:41]

Do we need this template?

[hajimehoshi, 2015/11/26 10:49:13]

Sorry but this was a test code. Removed.

+
+template<typename StringType>
+StringType v8StringToWebCoreString2(v8::Local<v8::String> v8String, ExternalMode external)

[haraken, 2015/11/24 11:15:41]

Ditto.

[hajimehoshi, 2015/11/26 10:49:13]

Done.

+{
+    {
+        // This portion of this function is very hot in certain Dromeao benchmarks.
+        v8::String::Encoding encoding;
+        v8::String::ExternalStringResourceBase* resource = v8String->GetExternalStringResourceBase(&encoding);
+        if (LIKELY(!!resource)) {
+            // TODO(hajimehoshi): What if resource is a compressablestring???
+            WebCoreStringResourceBase* base;
+            if (encoding == v8::String::ONE_BYTE_ENCODING)
+                base = static_cast<WebCoreStringResource8*>(resource);
+            else
+                base = static_cast<WebCoreStringResource16*>(resource);
+            return StringTraits<StringType>::fromStringResource(base);
+        }
+    }
+
+    int length = v8String->Length();
+    if (UNLIKELY(!length))
+        return StringType("");
+
+    bool oneByte = v8String->ContainsOnlyOneByte();
+    StringType result(oneByte ? StringTraits<StringType>::template fromV8String<V8StringOneByteTrait>(v8String, length) : StringTraits<StringType>::template fromV8String<V8StringTwoBytesTrait>(v8String, length));
+
+    if (external != Externalize || !v8String->CanMakeExternal())
+        return result;
+
+    if (result.is8Bit()) {
+        WebCoreStringResource8* stringResource = new WebCoreStringResource8(result);
+        if (UNLIKELY(!v8String->MakeExternal(stringResource)))
+            delete stringResource;
+    } else {
+        WebCoreStringResource16* stringResource = new WebCoreStringResource16(result);
+        if (UNLIKELY(!v8String->MakeExternal(stringResource)))
+            delete stringResource;
+    }
+    return result;
+}
+
 // Fast but non thread-safe version.
 String int32ToWebCoreStringFast(int value)
 {