libs/vr/libdvr/include/dvr/dvr_buffer_queue.h

#ifndef ANDROID_DVR_BUFFER_QUEUE_H_
#define ANDROID_DVR_BUFFER_QUEUE_H_

#include <sys/cdefs.h>

#include <dvr/dvr_buffer.h>

__BEGIN_DECLS

typedef struct ANativeWindow ANativeWindow;

typedef struct DvrWriteBufferQueue DvrWriteBufferQueue;
typedef struct DvrReadBufferQueue DvrReadBufferQueue;

// Destroy a write buffer queue.
//
// @param write_queue The DvrWriteBufferQueue of interest.
void dvrWriteBufferQueueDestroy(DvrWriteBufferQueue* write_queue);

// Get the total number of buffers in a write buffer queue.
//
// @param write_queue The DvrWriteBufferQueue of interest.
// @return The capacity on success; or negative error code.
ssize_t dvrWriteBufferQueueGetCapacity(DvrWriteBufferQueue* write_queue);

// Get the system unique queue id of a write buffer queue.
//
// @param write_queue The DvrWriteBufferQueue of interest.
// @return Queue id on success; or negative error code.
int dvrWriteBufferQueueGetId(DvrWriteBufferQueue* write_queue);

// Gets an ANativeWindow backed by the DvrWriteBufferQueue
//
// Can be casted to a Java Surface using ANativeWindow_toSurface NDK API. Note
// that the native window is lazily created at the first time |GetNativeWindow|
// is called, and the created ANativeWindow will be cached so that multiple
// calls to this method will return the same object. Also note that this method
// does not acquire an additional reference to the ANativeWindow returned, don't
// call ANativeWindow_release on it.
//
// @param write_queue The DvrWriteBufferQueue of interest.
// @param out_window The pointer of an ANativeWindow will be filled here if
//     the method call succeeds.
// @return Zero on success; or -EINVAL if this DvrWriteBufferQueue does not
//     support being used as an android Surface.
int dvrWriteBufferQueueGetExternalSurface(DvrWriteBufferQueue* write_queue,
                                          ANativeWindow** out_window);

// Create a read buffer queue from an existing write buffer queue.
//
// @param write_queue The DvrWriteBufferQueue of interest.
// @param out_read_queue The pointer of a DvrReadBufferQueue will be filled here
//     if the method call succeeds.
// @return Zero on success, or negative error code.
int dvrWriteBufferQueueCreateReadQueue(DvrWriteBufferQueue* write_queue,
                                       DvrReadBufferQueue** out_read_queue);

// Dequeue a buffer to write into.
//
// @param write_queue The DvrWriteBufferQueue of interest.
// @param timeout Specifies the number of milliseconds that the method will
//     block. Specifying a timeout of -1 causes it to block indefinitely,
//     while specifying a timeout equal to zero cause it to return immediately,
//     even if no buffers are available.
// @param out_buffer A targeting DvrWriteBuffer object to hold the output of the
//     dequeue operation. Must be created by |dvrWriteBufferCreateEmpty|.
// @param out_fence_fd A sync fence fd defined in NDK's sync.h API, which
//     signals the release of underlying buffer. The producer should wait until
//     this fence clears before writing data into it.
// @return Zero on success, or negative error code.
int dvrWriteBufferQueueDequeue(DvrWriteBufferQueue* write_queue, int timeout,
                               DvrWriteBuffer* out_buffer, int* out_fence_fd);

// Overrides buffer dimension with new width and height.
//
// After the call successfully returns, each |dvrWriteBufferQueueDequeue| call
// will return buffer with newly assigned |width| and |height|. When necessary,
// old buffer will be removed from the buffer queue and replaced with new buffer
// matching the new buffer size.
//
// @param write_queue The DvrWriteBufferQueue of interest.
// @param width Desired width, cannot be Zero.
// @param height Desired height, cannot be Zero.
// @return Zero on success, or negative error code.
int dvrWriteBufferQueueResizeBuffer(DvrWriteBufferQueue* write_queue,
                                    uint32_t width, uint32_t height);

// Destroy a read buffer queue.
//
// @param read_queue The DvrReadBufferQueue of interest.
void dvrReadBufferQueueDestroy(DvrReadBufferQueue* read_queue);

// Get the total number of buffers in a read buffer queue.
//
// @param read_queue The DvrReadBufferQueue of interest.
// @return The capacity on success; or negative error code.
ssize_t dvrReadBufferQueueGetCapacity(DvrReadBufferQueue* read_queue);

// Get the system unique queue id of a read buffer queue.
//
// @param read_queue The DvrReadBufferQueue of interest.
// @return Queue id on success; or negative error code.
int dvrReadBufferQueueGetId(DvrReadBufferQueue* read_queue);

// Get the event fd that signals when queue updates occur.
//
// Use ReadBufferQueueHandleEvents to trigger registered event callbacks.
//
// @param read_queue The DvrReadBufferQueue of interest.
// @return Fd on success; or negative error code.
int dvrReadBufferQueueGetEventFd(DvrReadBufferQueue* read_queue);

// Create a read buffer queue from an existing read buffer queue.
//
// @param read_queue The DvrReadBufferQueue of interest.
// @param out_read_queue The pointer of a DvrReadBufferQueue will be filled here
//     if the method call succeeds.
// @return Zero on success, or negative error code.
int dvrReadBufferQueueCreateReadQueue(DvrReadBufferQueue* read_queue,
                                      DvrReadBufferQueue** out_read_queue);

// Dequeue a buffer to read from.
//
// @param read_queue The DvrReadBufferQueue of interest.
// @param timeout Specifies the number of milliseconds that the method will
//     block. Specifying a timeout of -1 causes it to block indefinitely,
//     while specifying a timeout equal to zero cause it to return immediately,
//     even if no buffers are available.
// @param out_buffer A targeting DvrReadBuffer object to hold the output of the
//     dequeue operation. Must be created by |dvrReadBufferCreateEmpty|.
// @param out_fence_fd A sync fence fd defined in NDK's sync.h API, which
//     signals the release of underlying buffer. The consumer should wait until
//     this fence clears before reading data from it.
// @param out_meta The memory area where a metadata object will be filled.
//     Can be nullptr iff |meta_size_bytes| is zero (i.e., there is no
//     metadata).
// @param meta_size_bytes Size of the metadata object caller expects. If it
//     doesn't match the size of actually metadata transported by the buffer
//     queue, the method returns -EINVAL.
// @return Zero on success, or negative error code.
int dvrReadBufferQueueDequeue(DvrReadBufferQueue* read_queue, int timeout,
                              DvrReadBuffer* out_buffer, int* out_fence_fd,
                              void* out_meta, size_t meta_size_bytes);

// Callback function which will be called when a buffer is avaiable.
//
// Note that there is no guarantee of thread safety and on which thread the
// callback will be fired.
//
// @param context User provided opaque pointer.
typedef void (*DvrReadBufferQueueBufferAvailableCallback)(void* context);

// Set buffer avaiable callback.
//
// @param read_queue The DvrReadBufferQueue of interest.
// @param callback The callback function. Set this to NULL if caller no longer
//     needs to listen to new buffer available events.
// @param context User provided opaque pointer, will be passed back during
//     callback. The caller is responsible for ensuring the validity of the
//     context through the life cycle of the DvrReadBufferQueue.
// @return Zero on success, or negative error code.
int dvrReadBufferQueueSetBufferAvailableCallback(
    DvrReadBufferQueue* read_queue,
    DvrReadBufferQueueBufferAvailableCallback callback, void* context);

// Callback function which will be called when a buffer is about to be removed.
//
// Note that there is no guarantee of thread safety and on which thread the
// callback will be fired.
//
// @param buffer The buffer being removed. Once the callbacks returns, this
//     buffer will be dereferenced from the buffer queue. If user has ever
//     cached other DvrReadBuffer/AHardwareBuffer/EglImageKHR objects derived
//     from this buffer, it's the user's responsibility to clean them up.
//     Note that the ownership of the read buffer is not passed to this
//     callback, so it should call dvrReadBufferDestroy on the buffer.
// @param context User provided opaque pointer.
typedef void (*DvrReadBufferQueueBufferRemovedCallback)(DvrReadBuffer* buffer,
                                                        void* context);

// Set buffer removed callback.
//
// @param read_queue The DvrReadBufferQueue of interest.
// @param callback The callback function. Set this to NULL if caller no longer
//     needs to listen to buffer removed events.
// @param context User provided opaque pointer, will be passed back during
//     callback. The caller is responsible for ensuring the validity of the
//     context through the life cycle of the DvrReadBufferQueue.
// @return Zero on success, or negative error code.
int dvrReadBufferQueueSetBufferRemovedCallback(
    DvrReadBufferQueue* read_queue,
    DvrReadBufferQueueBufferRemovedCallback callback, void* context);

// Handle all pending events on the read queue.
//
// @param read_queue The DvrReadBufferQueue of interest.
// @return Zero on success, or negative error code.
int dvrReadBufferQueueHandleEvents(DvrReadBufferQueue* read_queue);

__END_DECLS

#endif  // ANDROID_DVR_BUFFER_QUEUE_H_