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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 "core/dom/MessagePort.h"
     29 
     30 #include "bindings/v8/ExceptionState.h"
     31 #include "bindings/v8/ExceptionStatePlaceholder.h"
     32 #include "bindings/v8/SerializedScriptValue.h"
     33 #include "core/dom/Document.h"
     34 #include "core/dom/ExceptionCode.h"
     35 #include "core/dom/ExecutionContext.h"
     36 #include "core/events/MessageEvent.h"
     37 #include "core/events/ThreadLocalEventNames.h"
     38 #include "core/frame/DOMWindow.h"
     39 #include "core/workers/WorkerGlobalScope.h"
     40 #include "public/platform/WebString.h"
     41 #include "wtf/Functional.h"
     42 #include "wtf/text/AtomicString.h"
     43 
     44 namespace WebCore {
     45 
     46 PassRefPtr<MessagePort> MessagePort::create(ExecutionContext& executionContext)
     47 {
     48     RefPtr<MessagePort> port = adoptRef(new MessagePort(executionContext));
     49     port->suspendIfNeeded();
     50     return port.release();
     51 }
     52 
     53 MessagePort::MessagePort(ExecutionContext& executionContext)
     54     : ActiveDOMObject(&executionContext)
     55     , m_started(false)
     56     , m_closed(false)
     57     , m_weakFactory(this)
     58 {
     59     ScriptWrappable::init(this);
     60 }
     61 
     62 MessagePort::~MessagePort()
     63 {
     64     close();
     65 }
     66 
     67 void MessagePort::postMessage(PassRefPtr<SerializedScriptValue> message, const MessagePortArray* ports, ExceptionState& exceptionState)
     68 {
     69     if (!isEntangled())
     70         return;
     71     ASSERT(executionContext());
     72     ASSERT(m_entangledChannel);
     73 
     74     OwnPtr<MessagePortChannelArray> channels;
     75     // Make sure we aren't connected to any of the passed-in ports.
     76     if (ports) {
     77         for (unsigned int i = 0; i < ports->size(); ++i) {
     78             MessagePort* dataPort = (*ports)[i].get();
     79             if (dataPort == this) {
     80                 exceptionState.throwDOMException(DataCloneError, "Item #" + String::number(i) + " in the array of ports contains the source port.");
     81                 return;
     82             }
     83         }
     84         channels = MessagePort::disentanglePorts(ports, exceptionState);
     85         if (exceptionState.hadException())
     86             return;
     87     }
     88 
     89     blink::WebString messageString = message->toWireString();
     90     blink::WebMessagePortChannelArray* webChannels = 0;
     91     if (channels && channels->size()) {
     92         webChannels = new blink::WebMessagePortChannelArray(channels->size());
     93         for (size_t i = 0; i < channels->size(); ++i)
     94             (*webChannels)[i] = (*channels)[i].leakPtr();
     95     }
     96     m_entangledChannel->postMessage(messageString, webChannels);
     97 }
     98 
     99 PassOwnPtr<blink::WebMessagePortChannel> MessagePort::disentangle()
    100 {
    101     ASSERT(m_entangledChannel);
    102     m_entangledChannel->setClient(0);
    103     return m_entangledChannel.release();
    104 }
    105 
    106 // Invoked to notify us that there are messages available for this port.
    107 // 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).
    108 void MessagePort::messageAvailable()
    109 {
    110     ASSERT(executionContext());
    111     executionContext()->postTask(bind(&MessagePort::dispatchMessages, m_weakFactory.createWeakPtr()));
    112 }
    113 
    114 void MessagePort::start()
    115 {
    116     // Do nothing if we've been cloned or closed.
    117     if (!isEntangled())
    118         return;
    119 
    120     ASSERT(executionContext());
    121     if (m_started)
    122         return;
    123 
    124     m_started = true;
    125     messageAvailable();
    126 }
    127 
    128 void MessagePort::close()
    129 {
    130     if (isEntangled())
    131         m_entangledChannel->setClient(0);
    132     m_closed = true;
    133 }
    134 
    135 void MessagePort::entangle(PassOwnPtr<blink::WebMessagePortChannel> remote)
    136 {
    137     // Only invoked to set our initial entanglement.
    138     ASSERT(!m_entangledChannel);
    139     ASSERT(executionContext());
    140 
    141     m_entangledChannel = remote;
    142     m_entangledChannel->setClient(this);
    143 }
    144 
    145 const AtomicString& MessagePort::interfaceName() const
    146 {
    147     return EventTargetNames::MessagePort;
    148 }
    149 
    150 static bool tryGetMessageFrom(blink::WebMessagePortChannel& webChannel, RefPtr<SerializedScriptValue>& message, OwnPtr<MessagePortChannelArray>& channels)
    151 {
    152     blink::WebString messageString;
    153     blink::WebMessagePortChannelArray webChannels;
    154     if (!webChannel.tryGetMessage(&messageString, webChannels))
    155         return false;
    156 
    157     if (webChannels.size()) {
    158         channels = adoptPtr(new MessagePortChannelArray(webChannels.size()));
    159         for (size_t i = 0; i < webChannels.size(); ++i)
    160             (*channels)[i] = adoptPtr(webChannels[i]);
    161     }
    162     message = SerializedScriptValue::createFromWire(messageString);
    163     return true;
    164 }
    165 
    166 void MessagePort::dispatchMessages()
    167 {
    168     // Messages for contexts that are not fully active get dispatched too, but JSAbstractEventListener::handleEvent() doesn't call handlers for these.
    169     // The HTML5 spec specifies that any messages sent to a document that is not fully active should be dropped, so this behavior is OK.
    170     if (!started())
    171         return;
    172 
    173     RefPtr<SerializedScriptValue> message;
    174     OwnPtr<MessagePortChannelArray> channels;
    175     while (m_entangledChannel && tryGetMessageFrom(*m_entangledChannel, message, channels)) {
    176         // close() in Worker onmessage handler should prevent next message from dispatching.
    177         if (executionContext()->isWorkerGlobalScope() && toWorkerGlobalScope(executionContext())->isClosing())
    178             return;
    179 
    180         OwnPtr<MessagePortArray> ports = MessagePort::entanglePorts(*executionContext(), channels.release());
    181         RefPtr<Event> evt = MessageEvent::create(ports.release(), message.release());
    182 
    183         dispatchEvent(evt.release(), ASSERT_NO_EXCEPTION);
    184     }
    185 }
    186 
    187 bool MessagePort::hasPendingActivity() const
    188 {
    189     // The spec says that entangled message ports should always be treated as if they have a strong reference.
    190     // 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).
    191     return m_started && isEntangled();
    192 }
    193 
    194 PassOwnPtr<MessagePortChannelArray> MessagePort::disentanglePorts(const MessagePortArray* ports, ExceptionState& exceptionState)
    195 {
    196     if (!ports || !ports->size())
    197         return nullptr;
    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 i = 0; i < ports->size(); ++i) {
    204         MessagePort* port = (*ports)[i].get();
    205         if (!port || port->isNeutered() || portSet.contains(port)) {
    206             String type;
    207             if (!port)
    208                 type = "null";
    209             else if (port->isNeutered())
    210                 type = "already neutered";
    211             else
    212                 type = "a duplicate";
    213             exceptionState.throwDOMException(DataCloneError, "Item #"  + String::number(i) + " in the array of ports is " + type + ".");
    214             return nullptr;
    215         }
    216         portSet.add(port);
    217     }
    218 
    219     // Passed-in ports passed validity checks, so we can disentangle them.
    220     OwnPtr<MessagePortChannelArray> portArray = adoptPtr(new MessagePortChannelArray(ports->size()));
    221     for (unsigned i = 0; i < ports->size(); ++i)
    222         (*portArray)[i] = (*ports)[i]->disentangle();
    223     return portArray.release();
    224 }
    225 
    226 PassOwnPtr<MessagePortArray> MessagePort::entanglePorts(ExecutionContext& context, PassOwnPtr<MessagePortChannelArray> channels)
    227 {
    228     if (!channels || !channels->size())
    229         return nullptr;
    230 
    231     OwnPtr<MessagePortArray> portArray = adoptPtr(new MessagePortArray(channels->size()));
    232     for (unsigned int i = 0; i < channels->size(); ++i) {
    233         RefPtr<MessagePort> port = MessagePort::create(context);
    234         port->entangle((*channels)[i].release());
    235         (*portArray)[i] = port.release();
    236     }
    237     return portArray.release();
    238 }
    239 
    240 } // namespace WebCore
    241