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      1 /*
      2  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  *
     25  */
     26 
     27 #include "config.h"
     28 #include "MessagePort.h"
     29 
     30 #include "DOMWindow.h"
     31 #include "Document.h"
     32 #include "EventException.h"
     33 #include "EventNames.h"
     34 #include "MessageEvent.h"
     35 #include "SecurityOrigin.h"
     36 #include "Timer.h"
     37 #include "WorkerContext.h"
     38 #include <wtf/text/AtomicString.h>
     39 
     40 namespace WebCore {
     41 
     42 MessagePort::MessagePort(ScriptExecutionContext& scriptExecutionContext)
     43     : m_entangledChannel(0)
     44     , m_started(false)
     45     , m_closed(false)
     46     , m_scriptExecutionContext(&scriptExecutionContext)
     47 {
     48     m_scriptExecutionContext->createdMessagePort(this);
     49 
     50     // Don't need to call processMessagePortMessagesSoon() here, because the port will not be opened until start() is invoked.
     51 }
     52 
     53 MessagePort::~MessagePort()
     54 {
     55     close();
     56     if (m_scriptExecutionContext)
     57         m_scriptExecutionContext->destroyedMessagePort(this);
     58 }
     59 
     60 // FIXME: remove this when we update the ObjC bindings (bug #28774).
     61 void MessagePort::postMessage(PassRefPtr<SerializedScriptValue> message, MessagePort* port, ExceptionCode& ec)
     62 {
     63     MessagePortArray ports;
     64     if (port)
     65         ports.append(port);
     66     postMessage(message, &ports, ec);
     67 }
     68 
     69 void MessagePort::postMessage(PassRefPtr<SerializedScriptValue> message, ExceptionCode& ec)
     70 {
     71     postMessage(message, static_cast<MessagePortArray*>(0), ec);
     72 }
     73 
     74 void MessagePort::postMessage(PassRefPtr<SerializedScriptValue> message, const MessagePortArray* ports, ExceptionCode& ec)
     75 {
     76     if (!isEntangled())
     77         return;
     78     ASSERT(m_scriptExecutionContext);
     79 
     80     OwnPtr<MessagePortChannelArray> channels;
     81     // Make sure we aren't connected to any of the passed-in ports.
     82     if (ports) {
     83         for (unsigned int i = 0; i < ports->size(); ++i) {
     84             MessagePort* dataPort = (*ports)[i].get();
     85             if (dataPort == this || m_entangledChannel->isConnectedTo(dataPort)) {
     86                 ec = INVALID_STATE_ERR;
     87                 return;
     88             }
     89         }
     90         channels = MessagePort::disentanglePorts(ports, ec);
     91         if (ec)
     92             return;
     93     }
     94     m_entangledChannel->postMessageToRemote(MessagePortChannel::EventData::create(message, channels.release()));
     95 }
     96 
     97 PassOwnPtr<MessagePortChannel> MessagePort::disentangle(ExceptionCode& ec)
     98 {
     99     if (!m_entangledChannel)
    100         ec = INVALID_STATE_ERR;
    101     else {
    102         m_entangledChannel->disentangle();
    103 
    104         // We can't receive any messages or generate any events, so remove ourselves from the list of active ports.
    105         ASSERT(m_scriptExecutionContext);
    106         m_scriptExecutionContext->destroyedMessagePort(this);
    107         m_scriptExecutionContext = 0;
    108     }
    109     return m_entangledChannel.release();
    110 }
    111 
    112 // Invoked to notify us that there are messages available for this port.
    113 // 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).
    114 void MessagePort::messageAvailable()
    115 {
    116     ASSERT(m_scriptExecutionContext);
    117     m_scriptExecutionContext->processMessagePortMessagesSoon();
    118 }
    119 
    120 void MessagePort::start()
    121 {
    122     // Do nothing if we've been cloned or closed.
    123     if (!isEntangled())
    124         return;
    125 
    126     ASSERT(m_scriptExecutionContext);
    127     if (m_started)
    128         return;
    129 
    130     m_started = true;
    131     m_scriptExecutionContext->processMessagePortMessagesSoon();
    132 }
    133 
    134 void MessagePort::close()
    135 {
    136     m_closed = true;
    137     if (!isEntangled())
    138         return;
    139     m_entangledChannel->close();
    140 }
    141 
    142 void MessagePort::entangle(PassOwnPtr<MessagePortChannel> remote)
    143 {
    144     // Only invoked to set our initial entanglement.
    145     ASSERT(!m_entangledChannel);
    146     ASSERT(m_scriptExecutionContext);
    147 
    148     // Don't entangle the ports if the channel is closed.
    149     if (remote->entangleIfOpen(this))
    150         m_entangledChannel = remote;
    151 }
    152 
    153 void MessagePort::contextDestroyed()
    154 {
    155     ASSERT(m_scriptExecutionContext);
    156     // Must be closed before blowing away the cached context, to ensure that we get no more calls to messageAvailable().
    157     // ScriptExecutionContext::closeMessagePorts() takes care of that.
    158     ASSERT(m_closed);
    159     m_scriptExecutionContext = 0;
    160 }
    161 
    162 ScriptExecutionContext* MessagePort::scriptExecutionContext() const
    163 {
    164     return m_scriptExecutionContext;
    165 }
    166 
    167 void MessagePort::dispatchMessages()
    168 {
    169     // Messages for contexts that are not fully active get dispatched too, but JSAbstractEventListener::handleEvent() doesn't call handlers for these.
    170     // The HTML5 spec specifies that any messages sent to a document that is not fully active should be dropped, so this behavior is OK.
    171     ASSERT(started());
    172 
    173     OwnPtr<MessagePortChannel::EventData> eventData;
    174     while (m_entangledChannel && m_entangledChannel->tryGetMessageFromRemote(eventData)) {
    175 
    176 #if ENABLE(WORKERS)
    177         // close() in Worker onmessage handler should prevent next message from dispatching.
    178         if (m_scriptExecutionContext->isWorkerContext() && static_cast<WorkerContext*>(m_scriptExecutionContext)->isClosing())
    179             return;
    180 #endif
    181 
    182         OwnPtr<MessagePortArray> ports = MessagePort::entanglePorts(*m_scriptExecutionContext, eventData->channels());
    183         RefPtr<Event> evt = MessageEvent::create(ports.release(), eventData->message());
    184 
    185         ExceptionCode ec = 0;
    186         dispatchEvent(evt.release(), ec);
    187         ASSERT(!ec);
    188     }
    189 }
    190 
    191 bool MessagePort::hasPendingActivity()
    192 {
    193     // The spec says that entangled message ports should always be treated as if they have a strong reference.
    194     // 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).
    195     return m_started && m_entangledChannel && m_entangledChannel->hasPendingActivity();
    196 }
    197 
    198 MessagePort* MessagePort::locallyEntangledPort()
    199 {
    200     return m_entangledChannel ? m_entangledChannel->locallyEntangledPort(m_scriptExecutionContext) : 0;
    201 }
    202 
    203 PassOwnPtr<MessagePortChannelArray> MessagePort::disentanglePorts(const MessagePortArray* ports, ExceptionCode& ec)
    204 {
    205     if (!ports || !ports->size())
    206         return 0;
    207 
    208     // HashSet used to efficiently check for duplicates in the passed-in array.
    209     HashSet<MessagePort*> portSet;
    210 
    211     // 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).
    212     for (unsigned int i = 0; i < ports->size(); ++i) {
    213         MessagePort* port = (*ports)[i].get();
    214         if (!port || port->isCloned() || portSet.contains(port)) {
    215             ec = INVALID_STATE_ERR;
    216             return 0;
    217         }
    218         portSet.add(port);
    219     }
    220 
    221     // Passed-in ports passed validity checks, so we can disentangle them.
    222     MessagePortChannelArray* portArray = new MessagePortChannelArray(ports->size());
    223     for (unsigned int i = 0 ; i < ports->size() ; ++i) {
    224         OwnPtr<MessagePortChannel> channel = (*ports)[i]->disentangle(ec);
    225         ASSERT(!ec); // Can't generate exception here if passed above checks.
    226         (*portArray)[i] = channel.release();
    227     }
    228     return portArray;
    229 }
    230 
    231 PassOwnPtr<MessagePortArray> MessagePort::entanglePorts(ScriptExecutionContext& context, PassOwnPtr<MessagePortChannelArray> channels)
    232 {
    233     if (!channels || !channels->size())
    234         return 0;
    235 
    236     MessagePortArray* portArray = new MessagePortArray(channels->size());
    237     for (unsigned int i = 0; i < channels->size(); ++i) {
    238         RefPtr<MessagePort> port = MessagePort::create(context);
    239         port->entangle((*channels)[i].release());
    240         (*portArray)[i] = port.release();
    241     }
    242     return portArray;
    243 }
    244 
    245 EventTargetData* MessagePort::eventTargetData()
    246 {
    247     return &m_eventTargetData;
    248 }
    249 
    250 EventTargetData* MessagePort::ensureEventTargetData()
    251 {
    252     return &m_eventTargetData;
    253 }
    254 
    255 } // namespace WebCore
    256