Simplify handling of Transferable objects while (de)serializing.

third_party/WebKit/Source/core/dom/MessagePort.cpp

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 48 matching lines @@
 {
 }
 
 MessagePort::~MessagePort()
 {
     close();
     if (m_scriptStateForConversion)
         m_scriptStateForConversion->disposePerContextData();
 }
 
-void MessagePort::postMessage(ExecutionContext* context, PassRefPtr<SerializedScriptValue> message, const MessagePortArray* ports, ExceptionState& exceptionState)
+void MessagePort::postMessage(ExecutionContext* context, PassRefPtr<SerializedScriptValue> message, const MessagePortArray& ports, ExceptionState& exceptionState)
 {
     if (!isEntangled())
         return;
     DCHECK(getExecutionContext());
     DCHECK(m_entangledChannel);
 
     OwnPtr<MessagePortChannelArray> channels;
     // Make sure we aren't connected to any of the passed-in ports.
-    if (ports) {
-        for (unsigned i = 0; i < ports->size(); ++i) {
-            MessagePort* dataPort = (*ports)[i];
-            if (dataPort == this) {
-                exceptionState.throwDOMException(DataCloneError, "Port at index " + String::number(i) + " contains the source port.");
-                return;
-            }
+    for (unsigned i = 0; i < ports.size(); ++i) {
+        if (ports[i] == this) {
+            exceptionState.throwDOMException(DataCloneError, "Port at index " + String::number(i) + " contains the source port.");
+            return;
         }
-        channels = MessagePort::disentanglePorts(context, ports, exceptionState);
-        if (exceptionState.hadException())
-            return;
     }
+    channels = MessagePort::disentanglePorts(context, ports, exceptionState);
+    if (exceptionState.hadException())
+        return;
 
     if (message->containsTransferableArrayBuffer())
         getExecutionContext()->addConsoleMessage(ConsoleMessage::create(JSMessageSource, WarningMessageLevel, "MessagePort cannot send an ArrayBuffer as a transferable object yet. See http://crbug.com/334408"));
 
     WebString messageString = message->toWireString();
     OwnPtr<WebMessagePortChannelArray> webChannels = toWebMessagePortChannelArray(channels.release());
     m_entangledChannel->postMessage(messageString, webChannels.leakPtr());
 }
 
 // static
@@ skipping 116 matching lines @@
     }
 }
 
 bool MessagePort::hasPendingActivity() const
 {
     // The spec says that entangled message ports should always be treated as if they have a strong reference.
     // We'll also stipulate that the queue needs to be open (if the app drops its reference to the port before start()-ing it, then it's not really entangled as it's unreachable).
     return m_started && isEntangled();
 }
 
-PassOwnPtr<MessagePortChannelArray> MessagePort::disentanglePorts(ExecutionContext* context, const MessagePortArray* ports, ExceptionState& exceptionState)
+PassOwnPtr<MessagePortChannelArray> MessagePort::disentanglePorts(ExecutionContext* context, const MessagePortArray& ports, ExceptionState& exceptionState)
 {
-    if (!ports || !ports->size())
+    if (!ports.size())
         return nullptr;
 
-    // HeapHashSet used to efficiently check for duplicates in the passed-in array.
-    HeapHashSet<Member<MessagePort>> portSet;
+    HeapHashSet<Member<MessagePort>> visited;
 
     // Walk the incoming array - if there are any duplicate ports, or null ports or cloned ports, throw an error (per section 8.3.3 of the HTML5 spec).
-    for (unsigned i = 0; i < ports->size(); ++i) {
-        MessagePort* port = (*ports)[i];
-        if (!port || port->isNeutered() || portSet.contains(port)) {
+    for (unsigned i = 0; i < ports.size(); ++i) {
+        MessagePort* port = ports[i];
+        if (!port || port->isNeutered() || visited.contains(port)) {
             String type;
             if (!port)
                 type = "null";
             else if (port->isNeutered())
                 type = "already neutered";
             else
                 type = "a duplicate";
             exceptionState.throwDOMException(DataCloneError, "Port at index "  + String::number(i) + " is " + type + ".");
             return nullptr;
         }
-        portSet.add(port);
+        visited.add(port);
     }
 
     UseCounter::count(context, UseCounter::MessagePortsTransferred);
 
     // Passed-in ports passed validity checks, so we can disentangle them.
-    OwnPtr<MessagePortChannelArray> portArray = adoptPtr(new MessagePortChannelArray(ports->size()));
-    for (unsigned i = 0; i < ports->size(); ++i)
-        (*portArray)[i] = (*ports)[i]->disentangle();
+    OwnPtr<MessagePortChannelArray> portArray = adoptPtr(new MessagePortChannelArray(ports.size()));
+    for (unsigned i = 0; i < ports.size(); ++i)
+        (*portArray)[i] = ports[i]->disentangle();
     return portArray.release();
 }
 
 MessagePortArray* MessagePort::entanglePorts(ExecutionContext& context, PassOwnPtr<MessagePortChannelArray> channels)
 {
     // https://html.spec.whatwg.org/multipage/comms.html#message-ports
     // |ports| should be an empty array, not null even when there is no ports.
     if (!channels || !channels->size())
         return new MessagePortArray;
 
@@ skipping 22 matching lines @@
 {
     DCHECK(getExecutionContext());
     if (!m_scriptStateForConversion) {
         v8::Isolate* isolate = scriptIsolate();
         m_scriptStateForConversion = ScriptState::create(v8::Context::New(isolate), DOMWrapperWorld::create(isolate));
     }
     return m_scriptStateForConversion->context();
 }
 
 } // namespace blink