Unfork MessagePort.cpp by postponing the entanglement of the message port JavaScript wrappers to GC time.

This have the drawback that message ports are "re-entangled/re-unentangled" for each GC which happens. This will most likely not make any noticable difference.
Review URL: http://codereview.chromium.org/14150

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@7053 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 37 insertions, 35 deletions

diff --git a/webkit/port/bindings/v8/ScriptController.cpp b/webkit/port/bindings/v8/ScriptController.cpp
index 1e4ffe4..99e35aa3 100644
--- a/webkit/port/bindings/v8/ScriptController.cpp
+++ b/webkit/port/bindings/v8/ScriptController.cpp
@@ -107,37 +107,6 @@ void ScriptController::gcUnprotectJSWrapper(void* dom_object)
     V8Proxy::GCUnprotect(dom_object);
 }
 
-void ScriptController::entangleMessagePorts(MessagePort *port1,
-                                            MessagePort *port2)
-{
-    // When two message ports are entangled make sure that the two wrappers are
-    // also entangled. If one of the ports has pending activity it's wrapper
-    // will be protected from beeing GC'ed and by entangeling the wrappers the
-    // wrapper for the entangled port will also be protected.
-    v8::Handle<v8::Value> port1_wrapper =
-      V8Proxy::ToV8Object(V8ClassIndex::MESSAGEPORT, port1);
-    v8::Handle<v8::Value> port2_wrapper =
-      V8Proxy::ToV8Object(V8ClassIndex::MESSAGEPORT, port2);
-    ASSERT(port1_wrapper->IsObject());
-    v8::Handle<v8::Object>::Cast(port1_wrapper)->SetInternalField(
-        V8Custom::kMessagePortEntangledPortIndex, port2_wrapper);
-    ASSERT(port2_wrapper->IsObject());
-    v8::Handle<v8::Object>::Cast(port2_wrapper)->SetInternalField(
-        V8Custom::kMessagePortEntangledPortIndex, port1_wrapper);
-}
-
-void ScriptController::unentangleMessagePort(MessagePort *port)
-{
-    // Remove the wrapper entanglement when a port is unentangled.
-    if (V8Proxy::DOMObjectHasJSWrapper(port)) {
-        v8::Handle<v8::Value> wrapper =
-            V8Proxy::ToV8Object(V8ClassIndex::MESSAGEPORT, port);
-        ASSERT(wrapper->IsObject());
-        v8::Handle<v8::Object>::Cast(wrapper)->SetInternalField(
-            V8Custom::kMessagePortEntangledPortIndex, v8::Undefined());
-    }
-}
-
 ScriptController::ScriptController(Frame* frame)
     : m_frame(frame)
     , m_sourceURL(0)
diff --git a/webkit/port/bindings/v8/ScriptController.h b/webkit/port/bindings/v8/ScriptController.h
index e42ecfb..16f2de8 100644
--- a/webkit/port/bindings/v8/ScriptController.h
+++ b/webkit/port/bindings/v8/ScriptController.h
@@ -206,10 +206,6 @@ public:
     static void gcProtectJSWrapper(void* object);
     static void gcUnprotectJSWrapper(void* object);
 
-    // Handle entangle/unentangle of message ports.
-    static void entangleMessagePorts(MessagePort *port1, MessagePort *port2);
-    static void unentangleMessagePort(MessagePort *port);
-
     // Get/Set RecordPlaybackMode flag.
     // This is a special mode where JS helps the browser implement
     // playback/record mode.  Generally, in this mode, some functions
diff --git a/webkit/port/bindings/v8/v8_proxy.cpp b/webkit/port/bindings/v8/v8_proxy.cpp
index 3bf5b5b..06e9aaf 100644
--- a/webkit/port/bindings/v8/v8_proxy.cpp
+++ b/webkit/port/bindings/v8/v8_proxy.cpp
@@ -674,6 +674,43 @@ ACTIVE_DOM_OBJECT_TYPES(MAKE_CASE)
         ASSERT(false);
 #undef MAKE_CASE
     }
+
+    // Additional handling of message port ensuring that entangled ports also
+    // have their wrappers entangled. This should ideally be handled when the
+    // ports are actually entangled in MessagePort::entangle, but to avoid
+    // forking MessagePort.* this is postponed to GC time. Having this postponed
+    // has the drawback that the wrappers are "entangled/unentangled" for each
+    // GC even though their entnaglement most likely is still the same.
+    if (type == V8ClassIndex::MESSAGEPORT) {
+      // Get the port and its entangled port.
+      MessagePort* port1 = static_cast<MessagePort*>(obj);
+      MessagePort* port2 = port1->entangledPort();
+      if (port2 != NULL) {
+        // As ports are always entangled in pairs only perform the entanglement
+        // once for each pair (see ASSERT in MessagePort::unentangle()).
+        if (port1 < port2) {
+          v8::Handle<v8::Value> port1_wrapper =
+              V8Proxy::ToV8Object(V8ClassIndex::MESSAGEPORT, port1);
+          v8::Handle<v8::Value> port2_wrapper =
+              V8Proxy::ToV8Object(V8ClassIndex::MESSAGEPORT, port2);
+          ASSERT(port1_wrapper->IsObject());
+          v8::Handle<v8::Object>::Cast(port1_wrapper)->SetInternalField(
+              V8Custom::kMessagePortEntangledPortIndex, port2_wrapper);
+          ASSERT(port2_wrapper->IsObject());
+          v8::Handle<v8::Object>::Cast(port2_wrapper)->SetInternalField(
+              V8Custom::kMessagePortEntangledPortIndex, port1_wrapper);
+        }
+      } else {
+        // Remove the wrapper entanglement when a port is not entangled.
+        if (V8Proxy::DOMObjectHasJSWrapper(port1)) {
+          v8::Handle<v8::Value> wrapper =
+            V8Proxy::ToV8Object(V8ClassIndex::MESSAGEPORT, port1);
+          ASSERT(wrapper->IsObject());
+          v8::Handle<v8::Object>::Cast(wrapper)->SetInternalField(
+            V8Custom::kMessagePortEntangledPortIndex, v8::Undefined());
+        }
+      }
+    }
   }
 
   // Create object groups.