00001 /* 00002 * Asterisk -- An open source telephony toolkit. 00003 * 00004 * Copyright (C) 1999 - 2005, Digium, Inc. 00005 * 00006 * Mark Spencer <markster@digium.com> 00007 * 00008 * See http://www.asterisk.org for more information about 00009 * the Asterisk project. Please do not directly contact 00010 * any of the maintainers of this project for assistance; 00011 * the project provides a web site, mailing lists and IRC 00012 * channels for your use. 00013 * 00014 * This program is free software, distributed under the terms of 00015 * the GNU General Public License Version 2. See the LICENSE file 00016 * at the top of the source tree. 00017 */ 00018 00019 /*! \file 00020 * \brief Asterisk PBX channel spy definitions 00021 */ 00022 00023 #ifndef _ASTERISK_CHANSPY_H 00024 #define _ASTERISK_CHANSPY_H 00025 00026 #if defined(__cplusplus) || defined(c_plusplus) 00027 extern "C" { 00028 #endif 00029 00030 #include "asterisk/linkedlists.h" 00031 00032 enum chanspy_states { 00033 CHANSPY_NEW = 0, /*!< spy not yet operating */ 00034 CHANSPY_RUNNING = 1, /*!< normal operation, spy is still operating */ 00035 CHANSPY_DONE = 2, /*!< spy is stopped and already removed from channel */ 00036 CHANSPY_STOP = 3, /*!< spy requested to stop, still attached to channel */ 00037 }; 00038 00039 enum chanspy_flags { 00040 CHANSPY_MIXAUDIO = (1 << 0), 00041 CHANSPY_READ_VOLADJUST = (1 << 1), 00042 CHANSPY_WRITE_VOLADJUST = (1 << 2), 00043 CHANSPY_FORMAT_AUDIO = (1 << 3), 00044 CHANSPY_TRIGGER_MODE = (3 << 4), 00045 CHANSPY_TRIGGER_READ = (1 << 4), 00046 CHANSPY_TRIGGER_WRITE = (2 << 4), 00047 CHANSPY_TRIGGER_NONE = (3 << 4), 00048 CHANSPY_TRIGGER_FLUSH = (1 << 6), 00049 }; 00050 00051 struct ast_channel_spy_queue { 00052 struct ast_frame *head; 00053 unsigned int samples; 00054 unsigned int format; 00055 }; 00056 00057 struct ast_channel_spy { 00058 AST_LIST_ENTRY(ast_channel_spy) list; 00059 ast_mutex_t lock; 00060 ast_cond_t trigger; 00061 struct ast_channel_spy_queue read_queue; 00062 struct ast_channel_spy_queue write_queue; 00063 unsigned int flags; 00064 enum chanspy_states status; 00065 const char *type; 00066 /* The volume adjustment values are very straightforward: 00067 positive values cause the samples to be multiplied by that amount 00068 negative values cause the samples to be divided by the absolute value of that amount 00069 */ 00070 int read_vol_adjustment; 00071 int write_vol_adjustment; 00072 }; 00073 00074 /*! 00075 \brief Adds a spy to a channel, to begin receiving copies of the channel's audio frames. 00076 \param chan The channel to add the spy to. 00077 \param spy A pointer to ast_channel_spy structure describing how the spy is to be used. 00078 \return 0 for success, non-zero for failure 00079 00080 Note: This function performs no locking; you must hold the channel's lock before 00081 calling this function. 00082 */ 00083 int ast_channel_spy_add(struct ast_channel *chan, struct ast_channel_spy *spy); 00084 00085 /*! 00086 \brief Remove a spy from a channel. 00087 \param chan The channel to remove the spy from 00088 \param spy The spy to be removed 00089 \return nothing 00090 00091 Note: This function performs no locking; you must hold the channel's lock before 00092 calling this function. 00093 */ 00094 void ast_channel_spy_remove(struct ast_channel *chan, struct ast_channel_spy *spy); 00095 00096 /*! 00097 \brief Find all spies of a particular type on a channel and stop them. 00098 \param chan The channel to operate on 00099 \param type A character string identifying the type of spies to be stopped 00100 \return nothing 00101 00102 Note: This function performs no locking; you must hold the channel's lock before 00103 calling this function. 00104 */ 00105 void ast_channel_spy_stop_by_type(struct ast_channel *chan, const char *type); 00106 00107 /*! 00108 \brief Read one (or more) frames of audio from a channel being spied upon. 00109 \param spy The spy to operate on 00110 \param samples The number of audio samples to read 00111 \return NULL for failure, one ast_frame pointer, or a chain of ast_frame pointers 00112 00113 This function can return multiple frames if the spy structure needs to be 'flushed' 00114 due to mismatched queue lengths, or if the spy structure is configured to return 00115 unmixed audio (in which case each call to this function will return a frame of audio 00116 from each side of channel). 00117 00118 Note: This function performs no locking; you must hold the spy's lock before calling 00119 this function. You must <b>not</b> hold the channel's lock at the same time. 00120 */ 00121 struct ast_frame *ast_channel_spy_read_frame(struct ast_channel_spy *spy, unsigned int samples); 00122 00123 /*! 00124 \brief Efficiently wait until audio is available for a spy, or an exception occurs. 00125 \param spy The spy to wait on 00126 \return nothing 00127 00128 Note: The locking rules for this function are non-obvious... first, you must <b>not</b> 00129 hold the channel's lock when calling this function. Second, you must hold the spy's lock 00130 before making the function call; while the function runs the lock will be released, and 00131 when the trigger event occurs, the lock will be re-obtained. This means that when control 00132 returns to your code, you will again hold the spy's lock. 00133 */ 00134 void ast_channel_spy_trigger_wait(struct ast_channel_spy *spy); 00135 00136 #if defined(__cplusplus) || defined(c_plusplus) 00137 } 00138 #endif 00139 00140 #endif /* _ASTERISK_CHANSPY_H */