Merge "MediaBufferGroup: release buffers in add_buffer when growth limit reached"

MediaBufferGroup::MediaBufferGroup(size_t buffers, size_t buffer_size, size_t growthLimit)

    : mGrowthLimit(growthLimit) {

    if (mGrowthLimit > 0 && buffers > mGrowthLimit) {

        ALOGW("Preallocated buffers %zu > growthLimit %zu, increasing growthLimit",

                buffers, mGrowthLimit);

        mGrowthLimit = buffers;

    }

    if (buffer_size >= kSharedMemoryThreshold) {

        ALOGD("creating MemoryDealer");

        // Using a single MemoryDealer is efficient for a group of shared memory objects.

void MediaBufferGroup::add_buffer(MediaBuffer *buffer) {

    Mutex::Autolock autoLock(mLock);

    // if we're above our growth limit, release buffers if we can

    for (auto it = mBuffers.begin();

            mGrowthLimit > 0

            && mBuffers.size() >= mGrowthLimit

            && it != mBuffers.end();) {

        if ((*it)->refcount() == 0) {

            (*it)->setObserver(nullptr);

            (*it)->release();

            it = mBuffers.erase(it);

        } else {

            ++it;

        }

    }

    buffer->setObserver(this);

    mBuffers.emplace_back(buffer);

    // optionally: mGrowthLimit = max(mGrowthLimit, mBuffers.size());

}

bool MediaBufferGroup::has_buffers() {