freetdm: add initial changes for FreeTDM channel history feature

libs/freetdm/mod_freetdm/mod_freetdm.c

@@ -3660,7 +3660,12 @@ SWITCH_STANDARD_API(ft_function)
 						if(chan_id > ftdm_span_get_chan_count(span)) {
 							stream->write_function(stream, "-ERR invalid channel\n");
 						} else {
+							char *dbgstr = NULL;
+							ftdm_channel_t *fchan = ftdm_span_get_channel(span, chan_id);
 							dump_chan(span, chan_id, stream);
+							dbgstr = ftdm_channel_get_history_str(fchan);
+							stream->write_function(stream, "%s\n", dbgstr);
+							ftdm_free(dbgstr);
 						}
 					} else {
 						stream->write_function(stream, "+OK\n");
@@ -3989,7 +3994,7 @@ SWITCH_STANDARD_API(ft_function)
 		
 		if (rply) {
 			stream->write_function(stream, "%s", rply);
-			free(rply);
+			ftdm_free(rply);
 		} else {
 			stream->write_function(stream, "-ERR Usage: %s\n", FT_SYNTAX);
 		}

libs/freetdm/src/ftdm_io.c

@@ -1293,6 +1293,16 @@ end:
 		ftdm_log_chan_ex(ftdmchan, file, func, line, FTDM_LOG_LEVEL_DEBUG, "Changed state from %s to %s\n", ftdm_channel_state2str(ftdmchan->state), ftdm_channel_state2str(state));
 		ftdmchan->last_state = ftdmchan->state; 
 		ftdmchan->state = state;
+		ftdmchan->history[ftdmchan->hindex].file = file;
+		ftdmchan->history[ftdmchan->hindex].func = func;
+		ftdmchan->history[ftdmchan->hindex].line = line;
+		ftdmchan->history[ftdmchan->hindex].state = ftdmchan->state;
+		ftdmchan->history[ftdmchan->hindex].last_state = ftdmchan->last_state;
+		ftdmchan->history[ftdmchan->hindex].time = ftdm_current_time_in_ms();
+		ftdmchan->hindex++;
+		if (ftdmchan->hindex == ftdm_array_len(ftdmchan->history)) {
+			ftdmchan->hindex = 0;
+		}
 		ftdm_set_flag(ftdmchan, FTDM_CHANNEL_STATE_CHANGE);
 
 		ftdm_mutex_lock(ftdmchan->span->mutex);
@@ -5213,6 +5223,57 @@ FT_DECLARE(char *) ftdm_strndup(const char *str, ftdm_size_t inlen)
 	return new;
 }
 
+#define FTDM_DEBUG_LINE_LEN 255
+FT_DECLARE(char *) ftdm_channel_get_history_str(const ftdm_channel_t *fchan)
+{
+	uint8_t j = 0;
+	int written = 0;
+	char *buff = NULL;
+	uint8_t i = fchan->hindex;
+	
+	int dbglen = ftdm_array_len(fchan->history) * FTDM_DEBUG_LINE_LEN;
+	int len = dbglen;
+
+	char *debugstr = ftdm_calloc(1, dbglen);
+	if (!debugstr) {
+		return NULL;
+	}
+	buff = debugstr;
+
+	for (i = fchan->hindex; i < ftdm_array_len(fchan->history); i++) {
+		if (!fchan->history[i].file) {
+			break;
+		}
+		written = snprintf(buff, len, "%s -> %s at %s %s:%d\n", 
+			ftdm_channel_state2str(fchan->history[i].last_state), ftdm_channel_state2str(fchan->history[i].state), fchan->history[i].func,
+			fchan->history[i].file, fchan->history[i].line);
+		if (written >= len) {
+			ftdm_free(debugstr);
+			ftdm_log(FTDM_LOG_ERROR, "Not enough memory to build debug history string\n");
+			return NULL;
+		}
+		len -= written;
+		buff += written;
+	}
+
+	for (j = 0; j < fchan->hindex; j++) {
+		written = snprintf(buff, len, "%s -> %s at %s %s:%d\n", 
+			ftdm_channel_state2str(fchan->history[i].last_state), ftdm_channel_state2str(fchan->history[i].state), fchan->history[i].func,
+			fchan->history[i].file, fchan->history[i].line);
+		if (written >= len) {
+			ftdm_free(debugstr);
+			ftdm_log(FTDM_LOG_ERROR, "Not enough memory to build debug history string\n");
+			return NULL;
+		}
+		len -= written;
+		buff += written;
+	}
+
+	debugstr[dbglen-1] = 0;
+
+	return debugstr;
+}
+
 
 /* For Emacs:
  * Local Variables:

libs/freetdm/src/include/freetdm.h

@@ -1277,7 +1277,13 @@ FT_DECLARE(const char *) ftdm_channel_get_state_str(const ftdm_channel_t *channe
 /*! \brief For display debugging purposes you can display this string which describes the last channel internal state */
 FT_DECLARE(const char *) ftdm_channel_get_last_state_str(const ftdm_channel_t *channel);
 
-/*! \brief For display debugging purposes you can display this string which describes the last channel internal state */
+/*! \brief For display debugging purposes you can display this string which describes the history of the channel 
+ *  \param The channel
+ *  \return History string for the channel. You must free the string with ftdm_free
+ */
+FT_DECLARE(char *) ftdm_channel_get_history_str(const ftdm_channel_t *channel);
+
+/*! \brief Initialize channel state for an outgoing call */
 FT_DECLARE(ftdm_status_t) ftdm_channel_init(ftdm_channel_t *ftdmchan);
 
 /*! \brief Initialize the library */

libs/freetdm/src/include/private/ftdm_core.h

@@ -356,6 +356,15 @@ typedef struct {
 } ftdm_dtmf_debug_t;
 #endif
 
+typedef struct {
+	const char *file;
+	const char *func;
+	int line;
+	ftdm_channel_state_t state;
+	ftdm_channel_state_t last_state;
+	ftdm_time_t time;
+} ftdm_channel_history_entry_t;
+
 /* 2^8 table size, one for each byte (sample) value */
 #define FTDM_GAINS_TABLE_SIZE 256
 struct ftdm_channel {
@@ -381,6 +390,8 @@ struct ftdm_channel {
 	ftdm_channel_state_t state;
 	ftdm_channel_state_t last_state;
 	ftdm_channel_state_t init_state;
+	ftdm_channel_history_entry_t history[10];
+	uint8_t hindex;
 	ftdm_mutex_t *mutex;
 	teletone_dtmf_detect_state_t dtmf_detect;
 	uint32_t buffer_delay;