xref: /frameworks/native/include/gui/IConsumerListener.h

/*
 * Copyright (C) 2013 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.
 */

#ifndef ANDROID_GUI_ICONSUMERLISTENER_H
#define ANDROID_GUI_ICONSUMERLISTENER_H

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

#include <utils/Errors.h>
#include <utils/RefBase.h>

#include <binder/IInterface.h>

namespace android {
// ----------------------------------------------------------------------------

class BufferItem;

// ConsumerListener is the interface through which the BufferQueue notifies
// the consumer of events that the consumer may wish to react to.  Because
// the consumer will generally have a mutex that is locked during calls from
// the consumer to the BufferQueue, these calls from the BufferQueue to the
// consumer *MUST* be called only when the BufferQueue mutex is NOT locked.

class ConsumerListener : public virtual RefBase {
public:
    ConsumerListener() { }
    virtual ~ConsumerListener() { }

    // onFrameAvailable is called from queueBuffer each time an additional
    // frame becomes available for consumption. This means that frames that
    // are queued while in asynchronous mode only trigger the callback if no
    // previous frames are pending. Frames queued while in synchronous mode
    // always trigger the callback. The item passed to the callback will contain
    // all of the information about the queued frame except for its
    // GraphicBuffer pointer, which will always be null.
    //
    // This is called without any lock held and can be called concurrently
    // by multiple threads.
    virtual void onFrameAvailable(const BufferItem& item) = 0; /* Asynchronous */

    // onFrameReplaced is called from queueBuffer if the frame being queued is
    // replacing an existing slot in the queue. Any call to queueBuffer that
    // doesn't call onFrameAvailable will call this callback instead. The item
    // passed to the callback will contain all of the information about the
    // queued frame except for its GraphicBuffer pointer, which will always be
    // null.
    //
    // This is called without any lock held and can be called concurrently
    // by multiple threads.
    virtual void onFrameReplaced(const BufferItem& item) {} /* Asynchronous */

    // onBuffersReleased is called to notify the buffer consumer that the
    // BufferQueue has released its references to one or more GraphicBuffers
    // contained in its slots.  The buffer consumer should then call
    // BufferQueue::getReleasedBuffers to retrieve the list of buffers
    //
    // This is called without any lock held and can be called concurrently
    // by multiple threads.
    virtual void onBuffersReleased() = 0; /* Asynchronous */

    // onSidebandStreamChanged is called to notify the buffer consumer that the
    // BufferQueue's sideband buffer stream has changed. This is called when a
    // stream is first attached and when it is either detached or replaced by a
    // different stream.
    virtual void onSidebandStreamChanged() = 0; /* Asynchronous */
};


class IConsumerListener : public ConsumerListener, public IInterface
{
public:
    DECLARE_META_INTERFACE(ConsumerListener);
};

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

class BnConsumerListener : public BnInterface<IConsumerListener>
{
public:
    virtual status_t    onTransact( uint32_t code,
                                    const Parcel& data,
                                    Parcel* reply,
                                    uint32_t flags = 0);
};

// ----------------------------------------------------------------------------
}; // namespace android

#endif // ANDROID_GUI_ICONSUMERLISTENER_H