flutter_flutter/engine/core/inspector/TraceEventDispatcher.cpp

/*
* Copyright (C) 2013 Google Inc. All rights reserved.
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#include "config.h"
#include "core/inspector/TraceEventDispatcher.h"

#include "wtf/CurrentTime.h"
#include "wtf/Functional.h"
#include "wtf/MainThread.h"
#include "wtf/text/StringHash.h"

namespace blink {

void TraceEventDispatcher::dispatchEventOnAnyThread(char phase, const unsigned char*, const char* name, unsigned long long id,
    int numArgs, const char* const* argNames, const unsigned char* argTypes, const unsigned long long* argValues,
    unsigned char flags, double timestamp)
{
    TraceEventDispatcher* self = instance();
    {
        MutexLocker locker(self->m_mutex);
        if (self->m_listeners->find(std::make_pair(name, phase)) == self->m_listeners->end())
            return;
    }
    self->enqueueEvent(TraceEvent(timestamp, phase, name, id, currentThread(), numArgs, argNames, argTypes, argValues));
    if (isMainThread())
        self->processBackgroundEvents();
}

void TraceEventDispatcher::enqueueEvent(const TraceEvent& event)
{
    const float eventProcessingThresholdInSeconds = 0.1;
    {
        MutexLocker locker(m_mutex);
        m_backgroundEvents.append(event);
        if (m_processEventsTaskInFlight || event.timestamp() - m_lastEventProcessingTime <= eventProcessingThresholdInSeconds)
            return;
    }
    m_processEventsTaskInFlight = true;
    callOnMainThread(bind(&TraceEventDispatcher::processBackgroundEventsTask, this));
}

void TraceEventDispatcher::processBackgroundEventsTask()
{
    m_processEventsTaskInFlight = false;
    processBackgroundEvents();
}

void TraceEventDispatcher::processBackgroundEvents()
{
    ASSERT(isMainThread());
    Vector<TraceEvent> events;
    {
        MutexLocker locker(m_mutex);
        m_lastEventProcessingTime = WTF::monotonicallyIncreasingTime();
        if (m_backgroundEvents.isEmpty())
            return;
        events.reserveCapacity(m_backgroundEvents.capacity());
        m_backgroundEvents.swap(events);
    }
    for (size_t eventIndex = 0, size = events.size(); eventIndex < size; ++eventIndex) {
        const TraceEvent& event = events[eventIndex];
        ListenersMap::iterator it = m_listeners->find(std::make_pair(event.name(), event.phase()));
        if (it == m_listeners->end())
            continue;
        WillBeHeapVector<OwnPtrWillBeMember<TraceEventListener> >& listeners = *it->value.get();
        for (size_t listenerIndex = 0; listenerIndex < listeners.size(); ++listenerIndex)
            listeners[listenerIndex]->call(event);
    }
}

void TraceEventDispatcher::addListener(const char* name, char phase, PassOwnPtrWillBeRawPtr<TraceEventListener> listener, InspectorClient* client)
{
    static const char CategoryFilter[] = "-*," TRACE_DISABLED_BY_DEFAULT("devtools.timeline") "," TRACE_DISABLED_BY_DEFAULT("devtools.timeline.frame");

    ASSERT(isMainThread());
    MutexLocker locker(m_mutex);
    if (m_listeners->isEmpty())
        client->setTraceEventCallback(CategoryFilter, dispatchEventOnAnyThread);
    ListenersMap::iterator it = m_listeners->find(std::make_pair(name, phase));
    if (it == m_listeners->end())
        m_listeners->add(std::make_pair(name, phase), adoptPtrWillBeNoop(new WillBeHeapVector<OwnPtrWillBeMember<TraceEventListener> >())).storedValue->value->append(listener);
    else
        it->value->append(listener);
}

void TraceEventDispatcher::removeAllListeners(void* eventTarget, InspectorClient* client)
{
    ASSERT(isMainThread());
    processBackgroundEvents();
    {
        MutexLocker locker(m_mutex);

        ListenersMap remainingListeners;
        for (ListenersMap::iterator it = m_listeners->begin(); it != m_listeners->end(); ++it) {
            WillBeHeapVector<OwnPtrWillBeMember<TraceEventListener> >& listeners = *it->value.get();
            for (size_t j = 0; j < listeners.size();) {
                if (listeners[j]->target() == eventTarget)
                    listeners.remove(j);
                else
                    ++j;
            }
            if (!listeners.isEmpty())
                remainingListeners.add(it->key, it->value.release());
        }
        m_listeners->swap(remainingListeners);
    }
    if (m_listeners->isEmpty())
        client->resetTraceEventCallback();
}

size_t TraceEventDispatcher::TraceEvent::findParameter(const char* name) const
{
    for (int i = 0; i < m_argumentCount; ++i) {
        if (!strcmp(name, m_argumentNames[i]))
            return i;
    }
    return kNotFound;
}

const TraceEvent::TraceValueUnion& TraceEventDispatcher::TraceEvent::parameter(const char* name, unsigned char expectedType) const
{
    static blink::TraceEvent::TraceValueUnion missingValue;
    size_t index = findParameter(name);
    ASSERT(isMainThread());
    if (index == kNotFound || m_argumentTypes[index] != expectedType) {
        ASSERT_NOT_REACHED();
        return missingValue;
    }
    return m_argumentValues[index];
}

} // namespace blink