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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 "AtomicString.h"
     31 #include "DOMWindow.h"
     32 #include "Document.h"
     33 #include "EventException.h"
     34 #include "EventNames.h"
     35 #include "MessageEvent.h"
     36 #include "SecurityOrigin.h"
     37 #include "Timer.h"
     38 
     39 namespace WebCore {
     40 
     41 MessagePort::MessagePort(ScriptExecutionContext& scriptExecutionContext)
     42     : m_entangledChannel(0)
     43     , m_started(false)
     44     , m_closed(false)
     45     , m_scriptExecutionContext(&scriptExecutionContext)
     46 {
     47     m_scriptExecutionContext->createdMessagePort(this);
     48 
     49     // Don't need to call processMessagePortMessagesSoon() here, because the port will not be opened until start() is invoked.
     50 }
     51 
     52 MessagePort::~MessagePort()
     53 {
     54     close();
     55     if (m_scriptExecutionContext)
     56         m_scriptExecutionContext->destroyedMessagePort(this);
     57 }
     58 
     59 // FIXME: remove this when we update the ObjC bindings (bug #28774).
     60 void MessagePort::postMessage(PassRefPtr<SerializedScriptValue> message, MessagePort* port, ExceptionCode& ec)
     61 {
     62     MessagePortArray ports;
     63     if (port)
     64         ports.append(port);
     65     postMessage(message, &ports, ec);
     66 }
     67 
     68 void MessagePort::postMessage(PassRefPtr<SerializedScriptValue> message, ExceptionCode& ec)
     69 {
     70     postMessage(message, static_cast<MessagePortArray*>(0), ec);
     71 }
     72 
     73 void MessagePort::postMessage(PassRefPtr<SerializedScriptValue> message, const MessagePortArray* ports, ExceptionCode& ec)
     74 {
     75     if (!m_entangledChannel)
     76         return;
     77     ASSERT(m_scriptExecutionContext);
     78 
     79     OwnPtr<MessagePortChannelArray> channels;
     80     // Make sure we aren't connected to any of the passed-in ports.
     81     if (ports) {
     82         for (unsigned int i = 0; i < ports->size(); ++i) {
     83             MessagePort* dataPort = (*ports)[i].get();
     84             if (dataPort == this || m_entangledChannel->isConnectedTo(dataPort)) {
     85                 ec = INVALID_STATE_ERR;
     86                 return;
     87             }
     88         }
     89         channels = MessagePort::disentanglePorts(ports, ec);
     90         if (ec)
     91             return;
     92     }
     93     m_entangledChannel->postMessageToRemote(MessagePortChannel::EventData::create(message, channels.release()));
     94 }
     95 
     96 PassOwnPtr<MessagePortChannel> MessagePort::disentangle(ExceptionCode& ec)
     97 {
     98     if (!m_entangledChannel)
     99         ec = INVALID_STATE_ERR;
    100     else {
    101         m_entangledChannel->disentangle();
    102 
    103         // We can't receive any messages or generate any events, so remove ourselves from the list of active ports.
    104         ASSERT(m_scriptExecutionContext);
    105         m_scriptExecutionContext->destroyedMessagePort(this);
    106         m_scriptExecutionContext = 0;
    107     }
    108     return m_entangledChannel.release();
    109 }
    110 
    111 // Invoked to notify us that there are messages available for this port.
    112 // 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).
    113 void MessagePort::messageAvailable()
    114 {
    115     ASSERT(m_scriptExecutionContext);
    116     m_scriptExecutionContext->processMessagePortMessagesSoon();
    117 }
    118 
    119 void MessagePort::start()
    120 {
    121     // Do nothing if we've been cloned
    122     if (!m_entangledChannel)
    123         return;
    124 
    125     ASSERT(m_scriptExecutionContext);
    126     if (m_started)
    127         return;
    128 
    129     m_started = true;
    130     m_scriptExecutionContext->processMessagePortMessagesSoon();
    131 }
    132 
    133 void MessagePort::close()
    134 {
    135     m_closed = true;
    136     if (!m_entangledChannel)
    137         return;
    138     m_entangledChannel->close();
    139 }
    140 
    141 void MessagePort::entangle(PassOwnPtr<MessagePortChannel> remote)
    142 {
    143     // Only invoked to set our initial entanglement.
    144     ASSERT(!m_entangledChannel);
    145     ASSERT(m_scriptExecutionContext);
    146 
    147     // Don't entangle the ports if the channel is closed.
    148     if (remote->entangleIfOpen(this))
    149         m_entangledChannel = remote;
    150 }
    151 
    152 void MessagePort::contextDestroyed()
    153 {
    154     ASSERT(m_scriptExecutionContext);
    155     // Must close port before blowing away the cached context, to ensure that we get no more calls to messageAvailable().
    156     close();
    157     m_scriptExecutionContext = 0;
    158 }
    159 
    160 ScriptExecutionContext* MessagePort::scriptExecutionContext() const
    161 {
    162     return m_scriptExecutionContext;
    163 }
    164 
    165 void MessagePort::dispatchMessages()
    166 {
    167     // Messages for contexts that are not fully active get dispatched too, but JSAbstractEventListener::handleEvent() doesn't call handlers for these.
    168     // The HTML5 spec specifies that any messages sent to a document that is not fully active should be dropped, so this behavior is OK.
    169     ASSERT(started());
    170 
    171     OwnPtr<MessagePortChannel::EventData> eventData;
    172     while (m_entangledChannel && m_entangledChannel->tryGetMessageFromRemote(eventData)) {
    173         OwnPtr<MessagePortArray> ports = MessagePort::entanglePorts(*m_scriptExecutionContext, eventData->channels());
    174         RefPtr<Event> evt = MessageEvent::create(ports.release(), eventData->message());
    175 
    176         ExceptionCode ec = 0;
    177         dispatchEvent(evt.release(), ec);
    178         ASSERT(!ec);
    179     }
    180 }
    181 
    182 bool MessagePort::hasPendingActivity()
    183 {
    184     // The spec says that entangled message ports should always be treated as if they have a strong reference.
    185     // 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).
    186     return m_started && m_entangledChannel && m_entangledChannel->hasPendingActivity();
    187 }
    188 
    189 MessagePort* MessagePort::locallyEntangledPort()
    190 {
    191     return m_entangledChannel ? m_entangledChannel->locallyEntangledPort(m_scriptExecutionContext) : 0;
    192 }
    193 
    194 PassOwnPtr<MessagePortChannelArray> MessagePort::disentanglePorts(const MessagePortArray* ports, ExceptionCode& ec)
    195 {
    196     if (!ports || !ports->size())
    197         return 0;
    198 
    199     // HashSet used to efficiently check for duplicates in the passed-in array.
    200     HashSet<MessagePort*> portSet;
    201 
    202     // 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).
    203     for (unsigned int i = 0; i < ports->size(); ++i) {
    204         MessagePort* port = (*ports)[i].get();
    205         if (!port || port->isCloned() || portSet.contains(port)) {
    206             ec = INVALID_STATE_ERR;
    207             return 0;
    208         }
    209         portSet.add(port);
    210     }
    211 
    212     // Passed-in ports passed validity checks, so we can disentangle them.
    213     MessagePortChannelArray* portArray = new MessagePortChannelArray(ports->size());
    214     for (unsigned int i = 0 ; i < ports->size() ; ++i) {
    215         OwnPtr<MessagePortChannel> channel = (*ports)[i]->disentangle(ec);
    216         ASSERT(!ec); // Can't generate exception here if passed above checks.
    217         (*portArray)[i] = channel.release();
    218     }
    219     return portArray;
    220 }
    221 
    222 PassOwnPtr<MessagePortArray> MessagePort::entanglePorts(ScriptExecutionContext& context, PassOwnPtr<MessagePortChannelArray> channels)
    223 {
    224     if (!channels || !channels->size())
    225         return 0;
    226 
    227     MessagePortArray* portArray = new MessagePortArray(channels->size());
    228     for (unsigned int i = 0; i < channels->size(); ++i) {
    229         RefPtr<MessagePort> port = MessagePort::create(context);
    230         port->entangle((*channels)[i].release());
    231         (*portArray)[i] = port.release();
    232     }
    233     return portArray;
    234 }
    235 
    236 EventTargetData* MessagePort::eventTargetData()
    237 {
    238     return &m_eventTargetData;
    239 }
    240 
    241 EventTargetData* MessagePort::ensureEventTargetData()
    242 {
    243     return &m_eventTargetData;
    244 }
    245 
    246 } // namespace WebCore
    247