services/surfaceflinger/Scheduler/MessageQueue.cpp

/*
 * Copyright (C) 2009 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <errno.h>
#include <stdint.h>
#include <sys/types.h>

#include <binder/IPCThreadState.h>

#include <utils/Log.h>
#include <utils/Timers.h>
#include <utils/threads.h>

#include <gui/DisplayEventReceiver.h>
#include <gui/IDisplayEventConnection.h>

#include "EventThread.h"
#include "MessageQueue.h"
#include "SurfaceFlinger.h"

namespace android {

// ---------------------------------------------------------------------------

MessageBase::MessageBase() : MessageHandler() {}

MessageBase::~MessageBase() {}

void MessageBase::handleMessage(const Message&) {
    this->handler();
    barrier.open();
};

// ---------------------------------------------------------------------------

MessageQueue::~MessageQueue() = default;

// ---------------------------------------------------------------------------

namespace impl {

void MessageQueue::Handler::dispatchRefresh() {
    if ((android_atomic_or(eventMaskRefresh, &mEventMask) & eventMaskRefresh) == 0) {
        mQueue.mLooper->sendMessage(this, Message(MessageQueue::REFRESH));
    }
}

void MessageQueue::Handler::dispatchInvalidate() {
    if ((android_atomic_or(eventMaskInvalidate, &mEventMask) & eventMaskInvalidate) == 0) {
        mQueue.mLooper->sendMessage(this, Message(MessageQueue::INVALIDATE));
    }
}

void MessageQueue::Handler::handleMessage(const Message& message) {
    switch (message.what) {
        case INVALIDATE:
            android_atomic_and(~eventMaskInvalidate, &mEventMask);
            mQueue.mFlinger->onMessageReceived(message.what);
            break;
        case REFRESH:
            android_atomic_and(~eventMaskRefresh, &mEventMask);
            mQueue.mFlinger->onMessageReceived(message.what);
            break;
    }
}

// ---------------------------------------------------------------------------

void MessageQueue::init(const sp<SurfaceFlinger>& flinger) {
    mFlinger = flinger;
    mLooper = new Looper(true);
    mHandler = new Handler(*this);
}

void MessageQueue::setEventThread(android::EventThread* eventThread,
                                  ResyncCallback resyncCallback) {
    if (mEventThread == eventThread) {
        return;
    }

    if (mEventTube.getFd() >= 0) {
        mLooper->removeFd(mEventTube.getFd());
    }

    mEventThread = eventThread;
    mEvents = eventThread->createEventConnection(std::move(resyncCallback));
    mEvents->stealReceiveChannel(&mEventTube);
    mLooper->addFd(mEventTube.getFd(), 0, Looper::EVENT_INPUT, MessageQueue::cb_eventReceiver,
                   this);
}

void MessageQueue::setEventConnection(const sp<EventThreadConnection>& connection) {
    if (mEventTube.getFd() >= 0) {
        mLooper->removeFd(mEventTube.getFd());
    }

    mEvents = connection;
    mEvents->stealReceiveChannel(&mEventTube);
    mLooper->addFd(mEventTube.getFd(), 0, Looper::EVENT_INPUT, MessageQueue::cb_eventReceiver,
                   this);
}

void MessageQueue::waitMessage() {
    do {
        IPCThreadState::self()->flushCommands();
        int32_t ret = mLooper->pollOnce(-1);
        switch (ret) {
            case Looper::POLL_WAKE:
            case Looper::POLL_CALLBACK:
                continue;
            case Looper::POLL_ERROR:
                ALOGE("Looper::POLL_ERROR");
                continue;
            case Looper::POLL_TIMEOUT:
                // timeout (should not happen)
                continue;
            default:
                // should not happen
                ALOGE("Looper::pollOnce() returned unknown status %d", ret);
                continue;
        }
    } while (true);
}

status_t MessageQueue::postMessage(const sp<MessageBase>& messageHandler, nsecs_t relTime) {
    const Message dummyMessage;
    if (relTime > 0) {
        mLooper->sendMessageDelayed(relTime, messageHandler, dummyMessage);
    } else {
        mLooper->sendMessage(messageHandler, dummyMessage);
    }
    return NO_ERROR;
}

void MessageQueue::invalidate() {
    mEvents->requestNextVsync();
}

void MessageQueue::refresh() {
    mHandler->dispatchRefresh();
}

int MessageQueue::cb_eventReceiver(int fd, int events, void* data) {
    MessageQueue* queue = reinterpret_cast<MessageQueue*>(data);
    return queue->eventReceiver(fd, events);
}

int MessageQueue::eventReceiver(int /*fd*/, int /*events*/) {
    ssize_t n;
    DisplayEventReceiver::Event buffer[8];
    while ((n = DisplayEventReceiver::getEvents(&mEventTube, buffer, 8)) > 0) {
        for (int i = 0; i < n; i++) {
            if (buffer[i].header.type == DisplayEventReceiver::DISPLAY_EVENT_VSYNC) {
                mHandler->dispatchInvalidate();
                break;
            }
        }
    }
    return 1;
}

// ---------------------------------------------------------------------------

} // namespace impl
} // namespace android