apps/app_stack.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (c) 2004-2006 Tilghman Lesher <app_stack_v002@the-tilghman.com>.
   5  *
   6  * This code is released by the author with no restrictions on usage.
   7  *
   8  * See http://www.asterisk.org for more information about
   9  * the Asterisk project. Please do not directly contact
  10  * any of the maintainers of this project for assistance;
  11  * the project provides a web site, mailing lists and IRC
  12  * channels for your use.
  13  *
  14  * This program is free software, distributed under the terms of
  15  * the GNU General Public License Version 2. See the LICENSE file
  16  * at the top of the source tree.
  17  */
  18
  19 /*! \file
  20  *
  21  * \brief Stack applications Gosub, Return, etc.
  22  *
  23  * \author Tilghman Lesher <app_stack_v002@the-tilghman.com>
  24  *
  25  * \ingroup applications
  26  */
  27
  28 #include "asterisk.h"
  29
  30 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  31
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <unistd.h>
  35 #include <string.h>
  36
  37 #include "asterisk/options.h"
  38 #include "asterisk/logger.h"
  39 #include "asterisk/channel.h"
  40 #include "asterisk/chanvars.h"
  41 #include "asterisk/pbx.h"
  42 #include "asterisk/module.h"
  43 #include "asterisk/config.h"
  44
  45 #define STACKVAR        "~GOSUB~STACK~"
  46
  47
  48 static const char *app_gosub = "Gosub";
  49 static const char *app_gosubif = "GosubIf";
  50 static const char *app_return = "Return";
  51 static const char *app_pop = "StackPop";
  52
  53 static const char *gosub_synopsis = "Jump to label, saving return address";
  54 static const char *gosubif_synopsis = "Conditionally jump to label, saving return address";
  55 static const char *return_synopsis = "Return from gosub routine";
  56 static const char *pop_synopsis = "Remove one address from gosub stack";
  57
  58 static const char *gosub_descrip =
  59 "Gosub([[context|]exten|]priority)\n"
  60 "  Jumps to the label specified, saving the return address.\n";
  61 static const char *gosubif_descrip =
  62 "GosubIf(condition?labeliftrue[:labeliffalse])\n"
  63 "  If the condition is true, then jump to labeliftrue.  If false, jumps to\n"
  64 "labeliffalse, if specified.  In either case, a jump saves the return point\n"
  65 "in the dialplan, to be returned to with a Return.\n";
  66 static const char *return_descrip =
  67 "Return()\n"
  68 "  Jumps to the last label on the stack, removing it.\n";
  69 static const char *pop_descrip =
  70 "StackPop()\n"
  71 "  Removes last label on the stack, discarding it.\n";
  72
  73
  74 static int pop_exec(struct ast_channel *chan, void *data)
  75 {
  76         pbx_builtin_setvar_helper(chan, STACKVAR, NULL);
  77
  78         return 0;
  79 }
  80
  81 static int return_exec(struct ast_channel *chan, void *data)
  82 {
  83         const char *label = pbx_builtin_getvar_helper(chan, STACKVAR);
  84
  85         if (ast_strlen_zero(label)) {
  86                 ast_log(LOG_ERROR, "Return without Gosub: stack is empty\n");
  87                 return -1;
  88         } else if (ast_parseable_goto(chan, label)) {
  89                 ast_log(LOG_WARNING, "No next statement after Gosub?\n");
  90                 return -1;
  91         }
  92
  93         pbx_builtin_setvar_helper(chan, STACKVAR, NULL);
  94         return 0;
  95 }
  96
  97 static int gosub_exec(struct ast_channel *chan, void *data)
  98 {
  99         char newlabel[AST_MAX_EXTENSION * 2 + 3 + 11];
 100         struct ast_module_user *u;
 101
 102         if (ast_strlen_zero(data)) {
 103                 ast_log(LOG_ERROR, "%s requires an argument: %s([[context|]exten|]priority)\n", app_gosub, app_gosub);
 104                 return -1;
 105         }
 106
 107         u = ast_module_user_add(chan);
 108         snprintf(newlabel, sizeof(newlabel), "%s|%s|%d", chan->context, chan->exten, chan->priority + 1);
 109
 110         if (ast_parseable_goto(chan, data)) {
 111                 ast_module_user_remove(u);
 112                 return -1;
 113         }
 114
 115         pbx_builtin_pushvar_helper(chan, STACKVAR, newlabel);
 116         ast_module_user_remove(u);
 117
 118         return 0;
 119 }
 120
 121 static int gosubif_exec(struct ast_channel *chan, void *data)
 122 {
 123         struct ast_module_user *u;
 124         char *condition="", *label1, *label2, *args;
 125         int res=0;
 126
 127         if (ast_strlen_zero(data)) {
 128                 ast_log(LOG_WARNING, "GosubIf requires an argument\n");
 129                 return 0;
 130         }
 131
 132         args = ast_strdupa(data);
 133
 134         u = ast_module_user_add(chan);
 135
 136         condition = strsep(&args, "?");
 137         label1 = strsep(&args, ":");
 138         label2 = args;
 139
 140         if (pbx_checkcondition(condition)) {
 141                 if (!ast_strlen_zero(label1)) {
 142                         res = gosub_exec(chan, label1);
 143                 }
 144         } else if (!ast_strlen_zero(label2)) {
 145                 res = gosub_exec(chan, label2);
 146         }
 147
 148         ast_module_user_remove(u);
 149         return res;
 150 }
 151
 152 static int unload_module(void)
 153 {
 154         ast_unregister_application(app_return);
 155         ast_unregister_application(app_pop);
 156         ast_unregister_application(app_gosubif);
 157         ast_unregister_application(app_gosub);
 158
 159         ast_module_user_hangup_all();
 160
 161         return 0;
 162 }
 163
 164 static int load_module(void)
 165 {
 166         ast_register_application(app_pop, pop_exec, pop_synopsis, pop_descrip);
 167         ast_register_application(app_return, return_exec, return_synopsis, return_descrip);
 168         ast_register_application(app_gosubif, gosubif_exec, gosubif_synopsis, gosubif_descrip);
 169         ast_register_application(app_gosub, gosub_exec, gosub_synopsis, gosub_descrip);
 170
 171         return 0;
 172 }
 173
 174 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Stack Routines");