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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/frame/LocalDOMWindow.h"
     38 #include "core/workers/WorkerGlobalScope.h"
     39 #include "public/platform/WebString.h"
     40 #include "wtf/Functional.h"
     41 #include "wtf/text/AtomicString.h"
     42 
     43 namespace WebCore {
     44 
     45 PassRefPtrWillBeRawPtr<MessagePort> MessagePort::create(ExecutionContext& executionContext)
     46 {
     47     RefPtrWillBeRawPtr<MessagePort> port = adoptRefWillBeRefCountedGarbageCollected(new MessagePort(executionContext));
     48     port->suspendIfNeeded();
     49     return port.release();
     50 }
     51 
     52 MessagePort::MessagePort(ExecutionContext& executionContext)
     53     : ActiveDOMObject(&executionContext)
     54     , m_started(false)
     55     , m_closed(false)
     56     , m_weakFactory(this)
     57 {
     58     ScriptWrappable::init(this);
     59 }
     60 
     61 MessagePort::~MessagePort()
     62 {
     63     close();
     64 }
     65 
     66 void MessagePort::postMessage(PassRefPtr<SerializedScriptValue> message, const MessagePortArray* ports, ExceptionState& exceptionState)
     67 {
     68     if (!isEntangled())
     69         return;
     70     ASSERT(executionContext());
     71     ASSERT(m_entangledChannel);
     72 
     73     OwnPtr<MessagePortChannelArray> channels;
     74     // Make sure we aren't connected to any of the passed-in ports.
     75     if (ports) {
     76         for (unsigned i = 0; i < ports->size(); ++i) {
     77             MessagePort* dataPort = (*ports)[i].get();
     78             if (dataPort == this) {
     79                 exceptionState.throwDOMException(DataCloneError, "Port at index " + String::number(i) + " contains the source port.");
     80                 return;
     81             }
     82         }
     83         channels = MessagePort::disentanglePorts(ports, exceptionState);
     84         if (exceptionState.hadException())
     85             return;
     86     }
     87 
     88     blink::WebString messageString = message->toWireString();
     89     OwnPtr<blink::WebMessagePortChannelArray> webChannels = toWebMessagePortChannelArray(channels.release());
     90     m_entangledChannel->postMessage(messageString, webChannels.leakPtr());
     91 }
     92 
     93 // static
     94 PassOwnPtr<blink::WebMessagePortChannelArray> MessagePort::toWebMessagePortChannelArray(PassOwnPtr<MessagePortChannelArray> channels)
     95 {
     96     OwnPtr<blink::WebMessagePortChannelArray> webChannels;
     97     if (channels && channels->size()) {
     98         webChannels = adoptPtr(new blink::WebMessagePortChannelArray(channels->size()));
     99         for (size_t i = 0; i < channels->size(); ++i)
    100             (*webChannels)[i] = (*channels)[i].leakPtr();
    101     }
    102     return webChannels.release();
    103 }
    104 
    105 // static
    106 PassOwnPtr<MessagePortArray> MessagePort::toMessagePortArray(ExecutionContext* context, const blink::WebMessagePortChannelArray& webChannels)
    107 {
    108     OwnPtr<MessagePortArray> ports;
    109     if (!webChannels.isEmpty()) {
    110         OwnPtr<MessagePortChannelArray> channels = adoptPtr(new MessagePortChannelArray(webChannels.size()));
    111         for (size_t i = 0; i < webChannels.size(); ++i)
    112             (*channels)[i] = adoptPtr(webChannels[i]);
    113         ports = MessagePort::entanglePorts(*context, channels.release());
    114     }
    115     return ports.release();
    116 }
    117 
    118 PassOwnPtr<blink::WebMessagePortChannel> MessagePort::disentangle()
    119 {
    120     ASSERT(m_entangledChannel);
    121     m_entangledChannel->setClient(0);
    122     return m_entangledChannel.release();
    123 }
    124 
    125 // Invoked to notify us that there are messages available for this port.
    126 // 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).
    127 void MessagePort::messageAvailable()
    128 {
    129     ASSERT(executionContext());
    130     executionContext()->postTask(bind(&MessagePort::dispatchMessages, m_weakFactory.createWeakPtr()));
    131 }
    132 
    133 void MessagePort::start()
    134 {
    135     // Do nothing if we've been cloned or closed.
    136     if (!isEntangled())
    137         return;
    138 
    139     ASSERT(executionContext());
    140     if (m_started)
    141         return;
    142 
    143     m_started = true;
    144     messageAvailable();
    145 }
    146 
    147 void MessagePort::close()
    148 {
    149     if (isEntangled())
    150         m_entangledChannel->setClient(0);
    151     m_closed = true;
    152 }
    153 
    154 void MessagePort::entangle(PassOwnPtr<blink::WebMessagePortChannel> remote)
    155 {
    156     // Only invoked to set our initial entanglement.
    157     ASSERT(!m_entangledChannel);
    158     ASSERT(executionContext());
    159 
    160     m_entangledChannel = remote;
    161     m_entangledChannel->setClient(this);
    162 }
    163 
    164 const AtomicString& MessagePort::interfaceName() const
    165 {
    166     return EventTargetNames::MessagePort;
    167 }
    168 
    169 static bool tryGetMessageFrom(blink::WebMessagePortChannel& webChannel, RefPtr<SerializedScriptValue>& message, OwnPtr<MessagePortChannelArray>& channels)
    170 {
    171     blink::WebString messageString;
    172     blink::WebMessagePortChannelArray webChannels;
    173     if (!webChannel.tryGetMessage(&messageString, webChannels))
    174         return false;
    175 
    176     if (webChannels.size()) {
    177         channels = adoptPtr(new MessagePortChannelArray(webChannels.size()));
    178         for (size_t i = 0; i < webChannels.size(); ++i)
    179             (*channels)[i] = adoptPtr(webChannels[i]);
    180     }
    181     message = SerializedScriptValue::createFromWire(messageString);
    182     return true;
    183 }
    184 
    185 void MessagePort::dispatchMessages()
    186 {
    187     // Messages for contexts that are not fully active get dispatched too, but JSAbstractEventListener::handleEvent() doesn't call handlers for these.
    188     // The HTML5 spec specifies that any messages sent to a document that is not fully active should be dropped, so this behavior is OK.
    189     if (!started())
    190         return;
    191 
    192     RefPtr<SerializedScriptValue> message;
    193     OwnPtr<MessagePortChannelArray> channels;
    194     while (m_entangledChannel && tryGetMessageFrom(*m_entangledChannel, message, channels)) {
    195         // close() in Worker onmessage handler should prevent next message from dispatching.
    196         if (executionContext()->isWorkerGlobalScope() && toWorkerGlobalScope(executionContext())->isClosing())
    197             return;
    198 
    199         OwnPtr<MessagePortArray> ports = MessagePort::entanglePorts(*executionContext(), channels.release());
    200         RefPtrWillBeRawPtr<Event> evt = MessageEvent::create(ports.release(), message.release());
    201 
    202         dispatchEvent(evt.release(), ASSERT_NO_EXCEPTION);
    203     }
    204 }
    205 
    206 bool MessagePort::hasPendingActivity() const
    207 {
    208     // The spec says that entangled message ports should always be treated as if they have a strong reference.
    209     // 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).
    210     return m_started && isEntangled();
    211 }
    212 
    213 PassOwnPtr<MessagePortChannelArray> MessagePort::disentanglePorts(const MessagePortArray* ports, ExceptionState& exceptionState)
    214 {
    215     if (!ports || !ports->size())
    216         return nullptr;
    217 
    218     // HashSet used to efficiently check for duplicates in the passed-in array.
    219     HashSet<MessagePort*> portSet;
    220 
    221     // 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).
    222     for (unsigned i = 0; i < ports->size(); ++i) {
    223         MessagePort* port = (*ports)[i].get();
    224         if (!port || port->isNeutered() || portSet.contains(port)) {
    225             String type;
    226             if (!port)
    227                 type = "null";
    228             else if (port->isNeutered())
    229                 type = "already neutered";
    230             else
    231                 type = "a duplicate";
    232             exceptionState.throwDOMException(DataCloneError, "Port at index "  + String::number(i) + " is " + type + ".");
    233             return nullptr;
    234         }
    235         portSet.add(port);
    236     }
    237 
    238     // Passed-in ports passed validity checks, so we can disentangle them.
    239     OwnPtr<MessagePortChannelArray> portArray = adoptPtr(new MessagePortChannelArray(ports->size()));
    240     for (unsigned i = 0; i < ports->size(); ++i)
    241         (*portArray)[i] = (*ports)[i]->disentangle();
    242     return portArray.release();
    243 }
    244 
    245 PassOwnPtr<MessagePortArray> MessagePort::entanglePorts(ExecutionContext& context, PassOwnPtr<MessagePortChannelArray> channels)
    246 {
    247     if (!channels || !channels->size())
    248         return nullptr;
    249 
    250     OwnPtr<MessagePortArray> portArray = adoptPtr(new MessagePortArray(channels->size()));
    251     for (unsigned i = 0; i < channels->size(); ++i) {
    252         RefPtr<MessagePort> port = MessagePort::create(context);
    253         port->entangle((*channels)[i].release());
    254         (*portArray)[i] = port.release();
    255     }
    256     return portArray.release();
    257 }
    258 
    259 } // namespace WebCore
    260