libqdutils/idle_invalidator.cpp

/*
 * Copyright (c) 2012, The Linux Foundation. All rights reserved.

 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   * Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.
 *   * Neither the name of The Linux Foundation nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "idle_invalidator.h"
#include <unistd.h>

#define II_DEBUG 0

static const char *threadName = "Invalidator";
InvalidatorHandler IdleInvalidator::mHandler = NULL;
android::sp<IdleInvalidator> IdleInvalidator::sInstance(0);

IdleInvalidator::IdleInvalidator(): Thread(false), mHwcContext(0),
    mSleepAgain(false), mSleepTime(0) {
        ALOGD_IF(II_DEBUG, "%s", __func__);
    }

int IdleInvalidator::init(InvalidatorHandler reg_handler, void* user_data,
                          unsigned int idleSleepTime) {
    ALOGD_IF(II_DEBUG, "%s", __func__);

    Locker::Autolock _l(mLock);
    /* store registered handler */
    mHandler = reg_handler;
    mHwcContext = user_data;
    mSleepTime = idleSleepTime; //Time in millis
    return 0;
}

bool IdleInvalidator::threadLoop() {
    struct timeval lastUpdateTime;
    ALOGD_IF(II_DEBUG, "%s", __func__);

    {
        //If we are here, update(s) happened, i.e mSleepAgain is set
        Locker::Autolock _l(mLock);
        mSleepAgain = false;
        lastUpdateTime = mLastUpdateTime;
    }

    struct timeval currentTime;
    gettimeofday(&currentTime, NULL);
    int timeSinceUpdateUs = (currentTime.tv_sec - lastUpdateTime.tv_sec) *
            1000000 + (currentTime.tv_usec - lastUpdateTime.tv_usec);
    int sleepDurationUs = mSleepTime * 1000 - timeSinceUpdateUs;

    //Sleep only if the duration required is > 1ms, otherwise its not worth it.
    if(sleepDurationUs > 1000) {
        usleep(sleepDurationUs);
        ALOGD_IF(II_DEBUG, "Slept for %d ms", sleepDurationUs / 1000);
    }

    Locker::Autolock _l(mLock);
    //If an update happened while we were asleep, sleep again
    if(mSleepAgain) {
        //We need to sleep again!
        mSleepAgain = false;
        return true;
    }

#if II_DEBUG
    gettimeofday(&currentTime, NULL);
    timeSinceUpdateUs = (currentTime.tv_sec - lastUpdateTime.tv_sec) *
            1000000 + (currentTime.tv_usec - lastUpdateTime.tv_usec);
    ALOGD("Idle refresh after %dms", timeSinceUpdateUs / 1000);
#endif

    mHandler((void*)mHwcContext);
    return false;
}

int IdleInvalidator::readyToRun() {
    ALOGD_IF(II_DEBUG, "%s", __func__);
    return 0; /*NO_ERROR*/
}

void IdleInvalidator::onFirstRef() {
    ALOGD_IF(II_DEBUG, "%s", __func__);
}

void IdleInvalidator::handleUpdateEvent() {
    Locker::Autolock _l(mLock);
    gettimeofday(&mLastUpdateTime, NULL);
    mSleepAgain = true;
    //Triggers the threadLoop to run, if not already running.
    run(threadName, android::PRIORITY_AUDIO);
}

IdleInvalidator *IdleInvalidator::getInstance() {
    ALOGD_IF(II_DEBUG, "%s", __func__);
    if(sInstance.get() == NULL)
        sInstance = new IdleInvalidator();
    return sInstance.get();
}