diff --git a/apps/app_if.c b/apps/app_if.c new file mode 100644 index 0000000000..b1ff0ada83 --- /dev/null +++ b/apps/app_if.c @@ -0,0 +1,382 @@ +/* + * Asterisk -- An open source telephony toolkit. + * + * Copyright 2022, Naveen Albert + * + * Naveen Albert + * + * 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 If Branch Implementation + * + * \author Naveen Albert + * + * \ingroup applications + */ + +/*** MODULEINFO + extended + ***/ + +#include "asterisk.h" + +#include "asterisk/pbx.h" +#include "asterisk/module.h" +#include "asterisk/channel.h" + +/*** DOCUMENTATION + + + Start an if branch. + + + + + + Start an If branch. Execution will continue inside the branch + if expr is true. + This application (and related applications) set variables + internally during execution. + + + ElseIf + Else + EndIf + ExitIf + + + + + Start an else if branch. + + + + + + Start an optional ElseIf branch. Execution will continue inside the branch + if expr is true and if previous If and ElseIf branches evaluated to false. + Please note that execution inside a true If branch will fallthrough into + ElseIf unless the If segment is terminated with an ExitIf call. This is only + necessary with ElseIf but not with Else. + + + If + Else + EndIf + ExitIf + + + + + Define an optional else branch. + + + + + + Start an Else branch. Execution will jump here if all previous + If and ElseIf branches evaluated to false. + + + If + ElseIf + EndIf + ExitIf + + + + + End an if branch. + + + + Ends the branch begun by the preceding If() application. + + + If + ElseIf + Else + ExitIf + + + + + End an If branch. + + + + Exits an If() branch, whether or not it has completed. + + + If + ElseIf + Else + EndIf + + + ***/ + +static char *if_app = "If"; +static char *elseif_app = "ElseIf"; +static char *else_app = "Else"; +static char *stop_app = "EndIf"; +static char *exit_app = "ExitIf"; + +#define VAR_SIZE 64 + +static const char *get_index(struct ast_channel *chan, const char *prefix, int idx) +{ + char varname[VAR_SIZE]; + + snprintf(varname, VAR_SIZE, "%s_%d", prefix, idx); + return pbx_builtin_getvar_helper(chan, varname); +} + +static struct ast_exten *find_matching_priority(struct ast_context *c, const char *exten, int priority, const char *callerid) +{ + struct ast_exten *e; + struct ast_context *c2; + int idx; + + for (e = ast_walk_context_extensions(c, NULL); e; e = ast_walk_context_extensions(c, e)) { + if (ast_extension_match(ast_get_extension_name(e), exten)) { + int needmatch = ast_get_extension_matchcid(e); + if ((needmatch && ast_extension_match(ast_get_extension_cidmatch(e), callerid)) || + (!needmatch)) { + /* This is the matching extension we want */ + struct ast_exten *p; + for (p = ast_walk_extension_priorities(e, NULL); p; p = ast_walk_extension_priorities(e, p)) { + if (priority != ast_get_extension_priority(p)) + continue; + return p; + } + } + } + } + + /* No match; run through includes */ + for (idx = 0; idx < ast_context_includes_count(c); idx++) { + const struct ast_include *i = ast_context_includes_get(c, idx); + + for (c2 = ast_walk_contexts(NULL); c2; c2 = ast_walk_contexts(c2)) { + if (!strcmp(ast_get_context_name(c2), ast_get_include_name(i))) { + e = find_matching_priority(c2, exten, priority, callerid); + if (e) + return e; + } + } + } + return NULL; +} + +static int find_matching_endif(struct ast_channel *chan, const char *otherapp) +{ + struct ast_context *c; + int res = -1; + + if (ast_rdlock_contexts()) { + ast_log(LOG_ERROR, "Failed to lock contexts list\n"); + return -1; + } + + for (c = ast_walk_contexts(NULL); c; c = ast_walk_contexts(c)) { + struct ast_exten *e; + + if (!ast_rdlock_context(c)) { + if (!strcmp(ast_get_context_name(c), ast_channel_context(chan))) { + /* This is the matching context we want */ + int cur_priority = ast_channel_priority(chan) + 1, level = 1; + + for (e = find_matching_priority(c, ast_channel_exten(chan), cur_priority, + S_COR(ast_channel_caller(chan)->id.number.valid, ast_channel_caller(chan)->id.number.str, NULL)); + e; + e = find_matching_priority(c, ast_channel_exten(chan), ++cur_priority, + S_COR(ast_channel_caller(chan)->id.number.valid, ast_channel_caller(chan)->id.number.str, NULL))) { + if (!strcasecmp(ast_get_extension_app(e), "IF")) { + level++; + } else if (!strcasecmp(ast_get_extension_app(e), "ENDIF")) { + level--; + } + + if (!otherapp && level == 0) { + res = cur_priority; + break; + } else if (otherapp && level == 1 && !strcasecmp(ast_get_extension_app(e), otherapp)) { + res = cur_priority; + break; + } + } + } + ast_unlock_context(c); + if (res > 0) { + break; + } + } + } + ast_unlock_contexts(); + return res; +} + +static int if_helper(struct ast_channel *chan, const char *data, int end) +{ + int res = 0; + const char *if_pri = NULL; + char *my_name = NULL; + const char *label = NULL; + char varname[VAR_SIZE], end_varname[VAR_SIZE + 4]; + const char *prefix = "IF"; + size_t size = 0; + int used_index_i = -1, x = 0; + char used_index[VAR_SIZE] = "0", new_index[VAR_SIZE] = "0"; + + if (!chan) { + return -1; + } + + for (x = 0 ;; x++) { + if (get_index(chan, prefix, x)) { + used_index_i = x; + } else { + break; + } + } + + snprintf(used_index, VAR_SIZE, "%d", used_index_i); + snprintf(new_index, VAR_SIZE, "%d", used_index_i + 1); + + size = strlen(ast_channel_context(chan)) + strlen(ast_channel_exten(chan)) + 32; + my_name = ast_alloca(size); + memset(my_name, 0, size); + snprintf(my_name, size, "%s_%s_%d", ast_channel_context(chan), ast_channel_exten(chan), ast_channel_priority(chan)); + + ast_channel_lock(chan); + if (end > 1) { + label = used_index; + } else if (!(label = pbx_builtin_getvar_helper(chan, my_name))) { + label = new_index; + pbx_builtin_setvar_helper(chan, my_name, label); + } + snprintf(varname, sizeof(varname), "%s_%s", prefix, label); + if ((if_pri = pbx_builtin_getvar_helper(chan, varname)) && !end) { + if_pri = ast_strdupa(if_pri); + snprintf(end_varname,sizeof(end_varname),"END_%s",varname); + } + ast_channel_unlock(chan); + + if ((end <= 1 && !pbx_checkcondition(ast_strdupa(data))) || (end > 1)) { + /* Condition Met (clean up helper vars) */ + const char *goto_str; + int pri, endifpri; + pbx_builtin_setvar_helper(chan, varname, NULL); + pbx_builtin_setvar_helper(chan, my_name, NULL); + snprintf(end_varname,sizeof(end_varname),"END_%s",varname); + ast_channel_lock(chan); + endifpri = find_matching_endif(chan, NULL); + if ((goto_str = pbx_builtin_getvar_helper(chan, end_varname))) { + ast_parseable_goto(chan, goto_str); + pbx_builtin_setvar_helper(chan, end_varname, NULL); + } else if (end <= 1 && (pri = find_matching_endif(chan, "ElseIf")) > 0 && pri < endifpri) { + pri--; /* back up a priority, since it returned the priority after the ElseIf */ + /* If is false, and ElseIf exists, so jump to ElseIf */ + ast_verb(3, "Taking conditional false branch, jumping to priority %d\n", pri); + ast_channel_priority_set(chan, pri); + } else if (end <= 1 && (pri = find_matching_endif(chan, "Else")) > 0 && pri < endifpri) { + /* don't need to back up a priority, because we don't actually need to execute Else, just jump to the priority after. Directly executing Else will exit the conditional. */ + /* If is false, and Else exists, so jump to Else */ + ast_verb(3, "Taking absolute false branch, jumping to priority %d\n", pri); + ast_channel_priority_set(chan, pri); + } else { + pri = endifpri; + if (pri > 0) { + ast_verb(3, "Exiting conditional, jumping to priority %d\n", pri); + ast_channel_priority_set(chan, pri); + } else if (end == 4) { /* Condition added because of end > 0 instead of end == 4 */ + ast_log(LOG_WARNING, "Couldn't find matching EndIf? (If at %s@%s priority %d)\n", ast_channel_context(chan), ast_channel_exten(chan), ast_channel_priority(chan)); + } + } + ast_channel_unlock(chan); + return res; + } + + if (end <= 1 && !if_pri) { + char *goto_str; + size = strlen(ast_channel_context(chan)) + strlen(ast_channel_exten(chan)) + 32; + goto_str = ast_alloca(size); + memset(goto_str, 0, size); + snprintf(goto_str, size, "%s,%s,%d", ast_channel_context(chan), ast_channel_exten(chan), ast_channel_priority(chan)); + pbx_builtin_setvar_helper(chan, varname, goto_str); + } else if (end > 1 && if_pri) { + /* END of branch */ + snprintf(end_varname, sizeof(end_varname), "END_%s", varname); + if (!pbx_builtin_getvar_helper(chan, end_varname)) { + char *goto_str; + size = strlen(ast_channel_context(chan)) + strlen(ast_channel_exten(chan)) + 32; + goto_str = ast_alloca(size); + memset(goto_str, 0, size); + snprintf(goto_str, size, "%s,%s,%d", ast_channel_context(chan), ast_channel_exten(chan), ast_channel_priority(chan)+1); + pbx_builtin_setvar_helper(chan, end_varname, goto_str); + } + ast_parseable_goto(chan, if_pri); + } + + return res; +} + +static int if_exec(struct ast_channel *chan, const char *data) { + return if_helper(chan, data, 0); +} + +static int elseif_exec(struct ast_channel *chan, const char *data) { + return if_helper(chan, data, 1); +} + +static int end_exec(struct ast_channel *chan, const char *data) { + return if_helper(chan, data, 2); +} + +static int else_exec(struct ast_channel *chan, const char *data) { + return if_helper(chan, data, 3); +} + +static int exit_exec(struct ast_channel *chan, const char *data) { + return if_helper(chan, data, 4); +} + +static int unload_module(void) +{ + int res; + + res = ast_unregister_application(if_app); + res |= ast_unregister_application(elseif_app); + res |= ast_unregister_application(stop_app); + res |= ast_unregister_application(else_app); + res |= ast_unregister_application(exit_app); + + return res; +} + +static int load_module(void) +{ + int res; + + res = ast_register_application_xml(if_app, if_exec); + res |= ast_register_application_xml(elseif_app, elseif_exec); + res |= ast_register_application_xml(stop_app, end_exec); + res |= ast_register_application_xml(else_app, else_exec); + res |= ast_register_application_xml(exit_app, exit_exec); + + return res; +} + +AST_MODULE_INFO_STANDARD_EXTENDED(ASTERISK_GPL_KEY, "If Branch and Conditional Execution"); diff --git a/doc/CHANGES-staging/app_if.txt b/doc/CHANGES-staging/app_if.txt new file mode 100644 index 0000000000..855f15aaf6 --- /dev/null +++ b/doc/CHANGES-staging/app_if.txt @@ -0,0 +1,4 @@ +Subject: app_if + +Adds the If, ElseIf, Else, EndIf, and ExitIf applications +for conditional execution of a block of code.