Wed Oct 28 11:50:55 2009

Asterisk developer's documentation


app_while.c

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00001 /*
00002  * Asterisk -- An open source telephony toolkit.
00003  *
00004  * Copyright 2004 - 2005, Anthony Minessale <anthmct@yahoo.com>
00005  *
00006  * Anthony Minessale <anthmct@yahoo.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  *
00021  * \brief While Loop Implementation
00022  *
00023  * \author Anthony Minessale <anthmct@yahoo.com>
00024  * 
00025  * \ingroup applications
00026  */
00027 
00028 #include "asterisk.h"
00029 
00030 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 156757 $")
00031 
00032 #include "asterisk/pbx.h"
00033 #include "asterisk/module.h"
00034 #include "asterisk/channel.h"
00035 
00036 static char *start_app = "While";
00037 static char *start_desc = 
00038 "  While(<expr>): Start a While Loop.  Execution will return to this\n"
00039 "point when EndWhile() is called until expr is no longer true.\n";
00040 
00041 static char *start_synopsis = "Start a while loop";
00042 
00043 
00044 static char *stop_app = "EndWhile";
00045 static char *stop_desc = 
00046 "  EndWhile(): Return to the previous called While()\n";
00047 
00048 static char *stop_synopsis = "End a while loop";
00049 
00050 static char *exit_app = "ExitWhile";
00051 static char *exit_desc =
00052 "  ExitWhile(): Exits a While() loop, whether or not the conditional has been satisfied.\n";
00053 static char *exit_synopsis = "End a While loop";
00054 
00055 static char *continue_app = "ContinueWhile";
00056 static char *continue_desc =
00057 "  ContinueWhile(): Returns to the top of the while loop and re-evaluates the conditional.\n";
00058 static char *continue_synopsis = "Restart a While loop";
00059 
00060 #define VAR_SIZE 64
00061 
00062 
00063 static const char *get_index(struct ast_channel *chan, const char *prefix, int idx) {
00064    char varname[VAR_SIZE];
00065 
00066    snprintf(varname, VAR_SIZE, "%s_%d", prefix, idx);
00067    return pbx_builtin_getvar_helper(chan, varname);
00068 }
00069 
00070 static struct ast_exten *find_matching_priority(struct ast_context *c, const char *exten, int priority, const char *callerid)
00071 {
00072    struct ast_exten *e;
00073    struct ast_include *i;
00074    struct ast_context *c2;
00075 
00076    for (e=ast_walk_context_extensions(c, NULL); e; e=ast_walk_context_extensions(c, e)) {
00077       if (ast_extension_match(ast_get_extension_name(e), exten)) {
00078          int needmatch = ast_get_extension_matchcid(e);
00079          if ((needmatch && ast_extension_match(ast_get_extension_cidmatch(e), callerid)) ||
00080             (!needmatch)) {
00081             /* This is the matching extension we want */
00082             struct ast_exten *p;
00083             for (p=ast_walk_extension_priorities(e, NULL); p; p=ast_walk_extension_priorities(e, p)) {
00084                if (priority != ast_get_extension_priority(p))
00085                   continue;
00086                return p;
00087             }
00088          }
00089       }
00090    }
00091 
00092    /* No match; run through includes */
00093    for (i=ast_walk_context_includes(c, NULL); i; i=ast_walk_context_includes(c, i)) {
00094       for (c2=ast_walk_contexts(NULL); c2; c2=ast_walk_contexts(c2)) {
00095          if (!strcmp(ast_get_context_name(c2), ast_get_include_name(i))) {
00096             e = find_matching_priority(c2, exten, priority, callerid);
00097             if (e)
00098                return e;
00099          }
00100       }
00101    }
00102    return NULL;
00103 }
00104 
00105 static int find_matching_endwhile(struct ast_channel *chan)
00106 {
00107    struct ast_context *c;
00108    int res=-1;
00109 
00110    if (ast_rdlock_contexts()) {
00111       ast_log(LOG_ERROR, "Failed to lock contexts list\n");
00112       return -1;
00113    }
00114 
00115    for (c=ast_walk_contexts(NULL); c; c=ast_walk_contexts(c)) {
00116       struct ast_exten *e;
00117 
00118       if (!ast_rdlock_context(c)) {
00119          if (!strcmp(ast_get_context_name(c), chan->context)) {
00120             /* This is the matching context we want */
00121             int cur_priority = chan->priority + 1, level=1;
00122 
00123             for (e = find_matching_priority(c, chan->exten, cur_priority, chan->cid.cid_num); e; e = find_matching_priority(c, chan->exten, ++cur_priority, chan->cid.cid_num)) {
00124                if (!strcasecmp(ast_get_extension_app(e), "WHILE")) {
00125                   level++;
00126                } else if (!strcasecmp(ast_get_extension_app(e), "ENDWHILE")) {
00127                   level--;
00128                }
00129 
00130                if (level == 0) {
00131                   res = cur_priority;
00132                   break;
00133                }
00134             }
00135          }
00136          ast_unlock_context(c);
00137          if (res > 0) {
00138             break;
00139          }
00140       }
00141    }
00142    ast_unlock_contexts();
00143    return res;
00144 }
00145 
00146 static int _while_exec(struct ast_channel *chan, void *data, int end)
00147 {
00148    int res=0;
00149    const char *while_pri = NULL;
00150    char *my_name = NULL;
00151    const char *condition = NULL, *label = NULL;
00152    char varname[VAR_SIZE], end_varname[VAR_SIZE];
00153    const char *prefix = "WHILE";
00154    size_t size=0;
00155    int used_index_i = -1, x=0;
00156    char used_index[VAR_SIZE] = "0", new_index[VAR_SIZE] = "0";
00157 
00158    if (!chan) {
00159       /* huh ? */
00160       return -1;
00161    }
00162 
00163 #if 0
00164    /* dont want run away loops if the chan isn't even up
00165       this is up for debate since it slows things down a tad ......
00166 
00167       Debate is over... this prevents While/EndWhile from working
00168       within the "h" extension.  Not good.
00169    */
00170    if (ast_waitfordigit(chan,1) < 0)
00171       return -1;
00172 #endif
00173 
00174    for (x=0;;x++) {
00175       if (get_index(chan, prefix, x)) {
00176          used_index_i = x;
00177       } else 
00178          break;
00179    }
00180    
00181    snprintf(used_index, VAR_SIZE, "%d", used_index_i);
00182    snprintf(new_index, VAR_SIZE, "%d", used_index_i + 1);
00183    
00184    if (!end)
00185       condition = ast_strdupa(data);
00186 
00187    size = strlen(chan->context) + strlen(chan->exten) + 32;
00188    my_name = alloca(size);
00189    memset(my_name, 0, size);
00190    snprintf(my_name, size, "%s_%s_%d", chan->context, chan->exten, chan->priority);
00191    
00192    ast_channel_lock(chan);
00193    if (end) {
00194       label = used_index;
00195    } else if (!(label = pbx_builtin_getvar_helper(chan, my_name))) {
00196       label = new_index;
00197       pbx_builtin_setvar_helper(chan, my_name, label);
00198    }
00199    snprintf(varname, VAR_SIZE, "%s_%s", prefix, label);
00200    if ((while_pri = pbx_builtin_getvar_helper(chan, varname)) && !end) {
00201       while_pri = ast_strdupa(while_pri);
00202       snprintf(end_varname,VAR_SIZE,"END_%s",varname);
00203    }
00204    ast_channel_unlock(chan);
00205    
00206 
00207    if ((!end && !pbx_checkcondition(condition)) || (end == 2)) {
00208       /* Condition Met (clean up helper vars) */
00209       const char *goto_str;
00210       pbx_builtin_setvar_helper(chan, varname, NULL);
00211       pbx_builtin_setvar_helper(chan, my_name, NULL);
00212       snprintf(end_varname,VAR_SIZE,"END_%s",varname);
00213       ast_channel_lock(chan);
00214       if ((goto_str = pbx_builtin_getvar_helper(chan, end_varname))) {
00215          ast_parseable_goto(chan, goto_str);
00216          pbx_builtin_setvar_helper(chan, end_varname, NULL);
00217       } else {
00218          int pri = find_matching_endwhile(chan);
00219          if (pri > 0) {
00220             ast_verb(3, "Jumping to priority %d\n", pri);
00221             chan->priority = pri;
00222          } else {
00223             ast_log(LOG_WARNING, "Couldn't find matching EndWhile? (While at %s@%s priority %d)\n", chan->context, chan->exten, chan->priority);
00224          }
00225       }
00226       ast_channel_unlock(chan);
00227       return res;
00228    }
00229 
00230    if (!end && !while_pri) {
00231       char *goto_str;
00232       size = strlen(chan->context) + strlen(chan->exten) + 32;
00233       goto_str = alloca(size);
00234       memset(goto_str, 0, size);
00235       snprintf(goto_str, size, "%s,%s,%d", chan->context, chan->exten, chan->priority);
00236       pbx_builtin_setvar_helper(chan, varname, goto_str);
00237    }
00238 
00239    else if (end && while_pri) {
00240       /* END of loop */
00241       snprintf(end_varname, VAR_SIZE, "END_%s", varname);
00242       if (! pbx_builtin_getvar_helper(chan, end_varname)) {
00243          char *goto_str;
00244          size = strlen(chan->context) + strlen(chan->exten) + 32;
00245          goto_str = alloca(size);
00246          memset(goto_str, 0, size);
00247          snprintf(goto_str, size, "%s,%s,%d", chan->context, chan->exten, chan->priority+1);
00248          pbx_builtin_setvar_helper(chan, end_varname, goto_str);
00249       }
00250       ast_parseable_goto(chan, while_pri);
00251    }
00252 
00253    return res;
00254 }
00255 
00256 static int while_start_exec(struct ast_channel *chan, void *data) {
00257    return _while_exec(chan, data, 0);
00258 }
00259 
00260 static int while_end_exec(struct ast_channel *chan, void *data) {
00261    return _while_exec(chan, data, 1);
00262 }
00263 
00264 static int while_exit_exec(struct ast_channel *chan, void *data) {
00265    return _while_exec(chan, data, 2);
00266 }
00267 
00268 static int while_continue_exec(struct ast_channel *chan, void *data)
00269 {
00270    int x;
00271    const char *prefix = "WHILE", *while_pri=NULL;
00272 
00273    for (x = 0; ; x++) {
00274       const char *tmp = get_index(chan, prefix, x);
00275       if (tmp)
00276          while_pri = tmp;
00277       else
00278          break;
00279    }
00280 
00281    if (while_pri)
00282       ast_parseable_goto(chan, while_pri);
00283 
00284    return 0;
00285 }
00286 
00287 static int unload_module(void)
00288 {
00289    int res;
00290    
00291    res = ast_unregister_application(start_app);
00292    res |= ast_unregister_application(stop_app);
00293    res |= ast_unregister_application(exit_app);
00294    res |= ast_unregister_application(continue_app);
00295 
00296    return res;
00297 }
00298 
00299 static int load_module(void)
00300 {
00301    int res;
00302 
00303    res = ast_register_application(start_app, while_start_exec, start_synopsis, start_desc);
00304    res |= ast_register_application(stop_app, while_end_exec, stop_synopsis, stop_desc);
00305    res |= ast_register_application(exit_app, while_exit_exec, exit_synopsis, exit_desc);
00306    res |= ast_register_application(continue_app, while_continue_exec, continue_synopsis, continue_desc);
00307 
00308    return res;
00309 }
00310 
00311 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "While Loops and Conditional Execution");

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