serval-dna/asterisk_include/asterisk/audiohook.h

/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2007, Digium, Inc.
 *
 * Joshua Colp <jcolp@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 * \brief Audiohooks Architecture
 */

#ifndef _ASTERISK_AUDIOHOOK_H
#define _ASTERISK_AUDIOHOOK_H

#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif

#include "asterisk/slinfactory.h"

enum ast_audiohook_type {
	AST_AUDIOHOOK_TYPE_SPY = 0,    /*!< Audiohook wants to receive audio */
	AST_AUDIOHOOK_TYPE_WHISPER,    /*!< Audiohook wants to provide audio to be mixed with existing audio */
	AST_AUDIOHOOK_TYPE_MANIPULATE, /*!< Audiohook wants to manipulate the audio */
};

enum ast_audiohook_status {
	AST_AUDIOHOOK_STATUS_NEW = 0,  /*!< Audiohook was just created, not in use yet */
	AST_AUDIOHOOK_STATUS_RUNNING,  /*!< Audiohook is running on a channel */
	AST_AUDIOHOOK_STATUS_SHUTDOWN, /*!< Audiohook is being shutdown */
	AST_AUDIOHOOK_STATUS_DONE,     /*!< Audiohook has shutdown and is not running on a channel any longer */
};

enum ast_audiohook_direction {
	AST_AUDIOHOOK_DIRECTION_READ = 0, /*!< Reading audio in */
	AST_AUDIOHOOK_DIRECTION_WRITE,    /*!< Writing audio out */
	AST_AUDIOHOOK_DIRECTION_BOTH,     /*!< Both reading audio in and writing audio out */
};

enum ast_audiohook_flags {
	AST_AUDIOHOOK_TRIGGER_MODE = (3 << 0),  /*!< When audiohook should be triggered to do something */
	AST_AUDIOHOOK_TRIGGER_READ = (1 << 0),  /*!< Audiohook wants to be triggered when reading audio in */
	AST_AUDIOHOOK_TRIGGER_WRITE = (2 << 0), /*!< Audiohook wants to be triggered when writing audio out */
	AST_AUDIOHOOK_WANTS_DTMF = (1 << 1),    /*!< Audiohook also wants to receive DTMF frames */
	AST_AUDIOHOOK_TRIGGER_SYNC = (1 << 2),  /*!< Audiohook wants to be triggered when both sides have combined audio available */
	/*! Audiohooks with this flag set will not allow for a large amount of samples to build up on its
	 * slinfactories. We will flush the factories if they contain too many samples.
	 */
	AST_AUDIOHOOK_SMALL_QUEUE = (1 << 3),
};

#define AST_AUDIOHOOK_SYNC_TOLERANCE 100 /*< Tolerance in milliseconds for audiohooks synchronization */

struct ast_audiohook;

/*! \brief Callback function for manipulate audiohook type
 * \param audiohook Audiohook structure
 * \param chan Channel
 * \param frame Frame of audio to manipulate
 * \param direction Direction frame came from
 * \return Returns 0 on success, -1 on failure.
 * \note An audiohook does not have any reference to a private data structure for manipulate
 *       types. It is up to the manipulate callback to store this data via it's own method.
 *       An example would be datastores.
 * \note The input frame should never be freed or corrupted during a manipulate callback.
 *       If the callback has the potential to corrupt the frame's data during manipulation,
 *       local data should be used for the manipulation and only copied to the frame on
 *       success.
 * \note A failure return value indicates that the frame was not manipulated and that
 *       is being returned in its original state.
 */
typedef int (*ast_audiohook_manipulate_callback)(struct ast_audiohook *audiohook, struct ast_channel *chan, struct ast_frame *frame, enum ast_audiohook_direction direction);

struct ast_audiohook_options {
	int read_volume;  /*!< Volume adjustment on frames read from the channel the hook is on */
	int write_volume; /*!< Volume adjustment on frames written to the channel the hook is on */
};

struct ast_audiohook {
	ast_mutex_t lock;                                      /*!< Lock that protects the audiohook structure */
	ast_cond_t trigger;                                    /*!< Trigger condition (if enabled) */
	enum ast_audiohook_type type;                          /*!< Type of audiohook */
	enum ast_audiohook_status status;                      /*!< Status of the audiohook */
	const char *source;                                    /*!< Who this audiohook ultimately belongs to */
	unsigned int flags;                                    /*!< Flags on the audiohook */
	struct ast_slinfactory read_factory;                   /*!< Factory where frames read from the channel, or read from the whisper source will go through */
	struct ast_slinfactory write_factory;                  /*!< Factory where frames written to the channel will go through */
	struct timeval read_time;                              /*!< Last time read factory was fed */
	struct timeval write_time;                             /*!< Last time write factory was fed */
	int format;                                            /*!< Format translation path is setup as */
	struct ast_trans_pvt *trans_pvt;                       /*!< Translation path for reading frames */
	ast_audiohook_manipulate_callback manipulate_callback; /*!< Manipulation callback */
	struct ast_audiohook_options options;                  /*!< Applicable options */
	AST_LIST_ENTRY(ast_audiohook) list;                    /*!< Linked list information */
};

struct ast_audiohook_list;

/*! \brief Initialize an audiohook structure
 * \param audiohook Audiohook structure
 * \param type Type of audiohook to initialize this as
 * \param source Who is initializing this audiohook
 * \return Returns 0 on success, -1 on failure
 */
int ast_audiohook_init(struct ast_audiohook *audiohook, enum ast_audiohook_type type, const char *source);

/*! \brief Destroys an audiohook structure
 * \param audiohook Audiohook structure
 * \return Returns 0 on success, -1 on failure
 */
int ast_audiohook_destroy(struct ast_audiohook *audiohook);

/*! \brief Writes a frame into the audiohook structure
 * \param audiohook Audiohook structure
 * \param direction Direction the audio frame came from
 * \param frame Frame to write in
 * \return Returns 0 on success, -1 on failure
 */
int ast_audiohook_write_frame(struct ast_audiohook *audiohook, enum ast_audiohook_direction direction, struct ast_frame *frame);

/*! \brief Reads a frame in from the audiohook structure
 * \param audiohook Audiohook structure
 * \param samples Number of samples wanted
 * \param direction Direction the audio frame came from
 * \param format Format of frame remote side wants back
 * \return Returns frame on success, NULL on failure
 */
struct ast_frame *ast_audiohook_read_frame(struct ast_audiohook *audiohook, size_t samples, enum ast_audiohook_direction direction, int format);

/*! \brief Attach audiohook to channel
 * \param chan Channel
 * \param audiohook Audiohook structure
 * \return Returns 0 on success, -1 on failure
 */
int ast_audiohook_attach(struct ast_channel *chan, struct ast_audiohook *audiohook);

/*! \brief Detach audiohook from channel
 * \param audiohook Audiohook structure
 * \return Returns 0 on success, -1 on failure
 */
int ast_audiohook_detach(struct ast_audiohook *audiohook);

/*! \brief Detach audiohooks from list and destroy said list
 * \param audiohook_list List of audiohooks
 * \return Returns 0 on success, -1 on failure
 */
int ast_audiohook_detach_list(struct ast_audiohook_list *audiohook_list);

/*! \brief Move an audiohook from one channel to a new one
 *
 * \todo Currently only the first audiohook of a specific source found will be moved.
 * We should add the capability to move multiple audiohooks from a single source as well.
 *
 * \note It is required that both old_chan and new_chan are locked prior to calling
 * this function. Besides needing to protect the data within the channels, not locking
 * these channels can lead to a potential deadlock
 *
 * \param old_chan The source of the audiohook to move
 * \param new_chan The destination to which we want the audiohook to move
 * \param source The source of the audiohook we want to move
 */
void ast_audiohook_move_by_source(struct ast_channel *old_chan, struct ast_channel *new_chan, const char *source);

/*! \brief Detach specified source audiohook from channel
 * \param chan Channel to detach from
 * \param source Name of source to detach
 * \return Returns 0 on success, -1 on failure
 */
int ast_audiohook_detach_source(struct ast_channel *chan, const char *source);

/*!
 * \brief Remove an audiohook from a specified channel
 *
 * \param chan Channel to remove from
 * \param audiohook Audiohook to remove
 *
 * \return Returns 0 on success, -1 on failure
 *
 * \note The channel does not need to be locked before calling this function
 */
int ast_audiohook_remove(struct ast_channel *chan, struct ast_audiohook *audiohook);

/*!
 * \brief determines if a audiohook_list is empty or not.
 *
 * retval 0 false, 1 true
 */
int ast_audiohook_write_list_empty(struct ast_audiohook_list *audiohook_list);

/*! \brief Pass a frame off to be handled by the audiohook core
 * \param chan Channel that the list is coming off of
 * \param audiohook_list List of audiohooks
 * \param direction Direction frame is coming in from
 * \param frame The frame itself
 * \return Return frame on success, NULL on failure
 */
struct ast_frame *ast_audiohook_write_list(struct ast_channel *chan, struct ast_audiohook_list *audiohook_list, enum ast_audiohook_direction direction, struct ast_frame *frame);

/*! \brief Wait for audiohook trigger to be triggered
 * \param audiohook Audiohook to wait on
 */
void ast_audiohook_trigger_wait(struct ast_audiohook *audiohook);

/*! \brief Lock an audiohook
 * \param ah Audiohook structure
 */
#define ast_audiohook_lock(ah) ast_mutex_lock(&(ah)->lock)

/*! \brief Unlock an audiohook
 * \param ah Audiohook structure
 */
#define ast_audiohook_unlock(ah) ast_mutex_unlock(&(ah)->lock)

#if defined(__cplusplus) || defined(c_plusplus)
}
#endif

#endif /* _ASTERISK_AUDIOHOOK_H */