WebCore/dom/MessagePort.cpp
changeset 0 4f2f89ce4247
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/dom/MessagePort.cpp	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,246 @@
+/*
+ * 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
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ *
+ */
+
+#include "config.h"
+#include "MessagePort.h"
+
+#include "AtomicString.h"
+#include "DOMWindow.h"
+#include "Document.h"
+#include "EventException.h"
+#include "EventNames.h"
+#include "MessageEvent.h"
+#include "SecurityOrigin.h"
+#include "Timer.h"
+
+namespace WebCore {
+
+MessagePort::MessagePort(ScriptExecutionContext& scriptExecutionContext)
+    : m_entangledChannel(0)
+    , m_started(false)
+    , m_closed(false)
+    , m_scriptExecutionContext(&scriptExecutionContext)
+{
+    m_scriptExecutionContext->createdMessagePort(this);
+
+    // Don't need to call processMessagePortMessagesSoon() here, because the port will not be opened until start() is invoked.
+}
+
+MessagePort::~MessagePort()
+{
+    close();
+    if (m_scriptExecutionContext)
+        m_scriptExecutionContext->destroyedMessagePort(this);
+}
+
+// FIXME: remove this when we update the ObjC bindings (bug #28774).
+void MessagePort::postMessage(PassRefPtr<SerializedScriptValue> message, MessagePort* port, ExceptionCode& ec)
+{
+    MessagePortArray ports;
+    if (port)
+        ports.append(port);
+    postMessage(message, &ports, ec);
+}
+
+void MessagePort::postMessage(PassRefPtr<SerializedScriptValue> message, ExceptionCode& ec)
+{
+    postMessage(message, static_cast<MessagePortArray*>(0), ec);
+}
+
+void MessagePort::postMessage(PassRefPtr<SerializedScriptValue> message, const MessagePortArray* ports, ExceptionCode& ec)
+{
+    if (!m_entangledChannel)
+        return;
+    ASSERT(m_scriptExecutionContext);
+
+    OwnPtr<MessagePortChannelArray> channels;
+    // Make sure we aren't connected to any of the passed-in ports.
+    if (ports) {
+        for (unsigned int i = 0; i < ports->size(); ++i) {
+            MessagePort* dataPort = (*ports)[i].get();
+            if (dataPort == this || m_entangledChannel->isConnectedTo(dataPort)) {
+                ec = INVALID_STATE_ERR;
+                return;
+            }
+        }
+        channels = MessagePort::disentanglePorts(ports, ec);
+        if (ec)
+            return;
+    }
+    m_entangledChannel->postMessageToRemote(MessagePortChannel::EventData::create(message, channels.release()));
+}
+
+PassOwnPtr<MessagePortChannel> MessagePort::disentangle(ExceptionCode& ec)
+{
+    if (!m_entangledChannel)
+        ec = INVALID_STATE_ERR;
+    else {
+        m_entangledChannel->disentangle();
+
+        // We can't receive any messages or generate any events, so remove ourselves from the list of active ports.
+        ASSERT(m_scriptExecutionContext);
+        m_scriptExecutionContext->destroyedMessagePort(this);
+        m_scriptExecutionContext = 0;
+    }
+    return m_entangledChannel.release();
+}
+
+// Invoked to notify us that there are messages available for this port.
+// This code may be called from another thread, and so should not call any non-threadsafe APIs (i.e. should not call into the entangled channel or access mutable variables).
+void MessagePort::messageAvailable()
+{
+    ASSERT(m_scriptExecutionContext);
+    m_scriptExecutionContext->processMessagePortMessagesSoon();
+}
+
+void MessagePort::start()
+{
+    // Do nothing if we've been cloned
+    if (!m_entangledChannel)
+        return;
+
+    ASSERT(m_scriptExecutionContext);
+    if (m_started)
+        return;
+
+    m_started = true;
+    m_scriptExecutionContext->processMessagePortMessagesSoon();
+}
+
+void MessagePort::close()
+{
+    m_closed = true;
+    if (!m_entangledChannel)
+        return;
+    m_entangledChannel->close();
+}
+
+void MessagePort::entangle(PassOwnPtr<MessagePortChannel> remote)
+{
+    // Only invoked to set our initial entanglement.
+    ASSERT(!m_entangledChannel);
+    ASSERT(m_scriptExecutionContext);
+
+    // Don't entangle the ports if the channel is closed.
+    if (remote->entangleIfOpen(this))
+        m_entangledChannel = remote;
+}
+
+void MessagePort::contextDestroyed()
+{
+    ASSERT(m_scriptExecutionContext);
+    // Must close port before blowing away the cached context, to ensure that we get no more calls to messageAvailable().
+    close();
+    m_scriptExecutionContext = 0;
+}
+
+ScriptExecutionContext* MessagePort::scriptExecutionContext() const
+{
+    return m_scriptExecutionContext;
+}
+
+void MessagePort::dispatchMessages()
+{
+    // Messages for contexts that are not fully active get dispatched too, but JSAbstractEventListener::handleEvent() doesn't call handlers for these.
+    // The HTML5 spec specifies that any messages sent to a document that is not fully active should be dropped, so this behavior is OK.
+    ASSERT(started());
+
+    OwnPtr<MessagePortChannel::EventData> eventData;
+    while (m_entangledChannel && m_entangledChannel->tryGetMessageFromRemote(eventData)) {
+        OwnPtr<MessagePortArray> ports = MessagePort::entanglePorts(*m_scriptExecutionContext, eventData->channels());
+        RefPtr<Event> evt = MessageEvent::create(ports.release(), eventData->message());
+
+        ExceptionCode ec = 0;
+        dispatchEvent(evt.release(), ec);
+        ASSERT(!ec);
+    }
+}
+
+bool MessagePort::hasPendingActivity()
+{
+    // 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 && m_entangledChannel && m_entangledChannel->hasPendingActivity();
+}
+
+MessagePort* MessagePort::locallyEntangledPort()
+{
+    return m_entangledChannel ? m_entangledChannel->locallyEntangledPort(m_scriptExecutionContext) : 0;
+}
+
+PassOwnPtr<MessagePortChannelArray> MessagePort::disentanglePorts(const MessagePortArray* ports, ExceptionCode& ec)
+{
+    if (!ports || !ports->size())
+        return 0;
+
+    // HashSet used to efficiently check for duplicates in the passed-in array.
+    HashSet<MessagePort*> portSet;
+
+    // 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 int i = 0; i < ports->size(); ++i) {
+        MessagePort* port = (*ports)[i].get();
+        if (!port || port->isCloned() || portSet.contains(port)) {
+            ec = INVALID_STATE_ERR;
+            return 0;
+        }
+        portSet.add(port);
+    }
+
+    // Passed-in ports passed validity checks, so we can disentangle them.
+    MessagePortChannelArray* portArray = new MessagePortChannelArray(ports->size());
+    for (unsigned int i = 0 ; i < ports->size() ; ++i) {
+        OwnPtr<MessagePortChannel> channel = (*ports)[i]->disentangle(ec);
+        ASSERT(!ec); // Can't generate exception here if passed above checks.
+        (*portArray)[i] = channel.release();
+    }
+    return portArray;
+}
+
+PassOwnPtr<MessagePortArray> MessagePort::entanglePorts(ScriptExecutionContext& context, PassOwnPtr<MessagePortChannelArray> channels)
+{
+    if (!channels || !channels->size())
+        return 0;
+
+    MessagePortArray* portArray = new MessagePortArray(channels->size());
+    for (unsigned int i = 0; i < channels->size(); ++i) {
+        RefPtr<MessagePort> port = MessagePort::create(context);
+        port->entangle((*channels)[i].release());
+        (*portArray)[i] = port.release();
+    }
+    return portArray;
+}
+
+EventTargetData* MessagePort::eventTargetData()
+{
+    return &m_eventTargetData;
+}
+
+EventTargetData* MessagePort::ensureEventTargetData()
+{
+    return &m_eventTargetData;
+}
+
+} // namespace WebCore