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Diffstat (limited to 'trunk/apps/app_stack.c')
-rw-r--r-- | trunk/apps/app_stack.c | 416 |
1 files changed, 416 insertions, 0 deletions
diff --git a/trunk/apps/app_stack.c b/trunk/apps/app_stack.c new file mode 100644 index 000000000..7f53aff15 --- /dev/null +++ b/trunk/apps/app_stack.c @@ -0,0 +1,416 @@ +/* + * Asterisk -- An open source telephony toolkit. + * + * Copyright (c) 2004-2006 Tilghman Lesher <app_stack_v003@the-tilghman.com>. + * + * This code is released by the author with no restrictions on usage. + * + * 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 Stack applications Gosub, Return, etc. + * + * \author Tilghman Lesher <app_stack_v003@the-tilghman.com> + * + * \ingroup applications + */ + +#include "asterisk.h" + +ASTERISK_FILE_VERSION(__FILE__, "$Revision$") + +#include "asterisk/pbx.h" +#include "asterisk/module.h" +#include "asterisk/app.h" +#include "asterisk/manager.h" +#include "asterisk/channel.h" + +static const char *app_gosub = "Gosub"; +static const char *app_gosubif = "GosubIf"; +static const char *app_return = "Return"; +static const char *app_pop = "StackPop"; + +static const char *gosub_synopsis = "Jump to label, saving return address"; +static const char *gosubif_synopsis = "Conditionally jump to label, saving return address"; +static const char *return_synopsis = "Return from gosub routine"; +static const char *pop_synopsis = "Remove one address from gosub stack"; + +static const char *gosub_descrip = +" Gosub([[context,]exten,]priority[(arg1[,...][,argN])]):\n" +"Jumps to the label specified, saving the return address.\n"; +static const char *gosubif_descrip = +" GosubIf(condition?labeliftrue[(arg1[,...])][:labeliffalse[(arg1[,...])]]):\n" +"If the condition is true, then jump to labeliftrue. If false, jumps to\n" +"labeliffalse, if specified. In either case, a jump saves the return point\n" +"in the dialplan, to be returned to with a Return.\n"; +static const char *return_descrip = +" Return([return-value]):\n" +"Jumps to the last label on the stack, removing it. The return value, if\n" +"any, is saved in the channel variable GOSUB_RETVAL.\n"; +static const char *pop_descrip = +" StackPop():\n" +"Removes last label on the stack, discarding it.\n"; + + +static void gosub_free(void *data); + +static struct ast_datastore_info stack_info = { + .type = "GOSUB", + .destroy = gosub_free, +}; + +struct gosub_stack_frame { + AST_LIST_ENTRY(gosub_stack_frame) entries; + /* 100 arguments is all that we support anyway, but this will handle up to 255 */ + unsigned char arguments; + struct varshead varshead; + int priority; + char *context; + char extension[0]; +}; + +static int frame_set_var(struct ast_channel *chan, struct gosub_stack_frame *frame, const char *var, const char *value) +{ + struct ast_var_t *variables; + int found = 0; + + /* Does this variable already exist? */ + AST_LIST_TRAVERSE(&frame->varshead, variables, entries) { + if (!strcmp(var, ast_var_name(variables))) { + found = 1; + break; + } + } + + if (!ast_strlen_zero(value)) { + if (!found) { + variables = ast_var_assign(var, ""); + AST_LIST_INSERT_HEAD(&frame->varshead, variables, entries); + pbx_builtin_pushvar_helper(chan, var, value); + } else + pbx_builtin_setvar_helper(chan, var, value); + + manager_event(EVENT_FLAG_DIALPLAN, "VarSet", + "Channel: %s\r\n" + "Variable: LOCAL(%s)\r\n" + "Value: %s\r\n" + "Uniqueid: %s\r\n", + chan->name, var, value, chan->uniqueid); + } + return 0; +} + +static void gosub_release_frame(struct ast_channel *chan, struct gosub_stack_frame *frame) +{ + unsigned char i; + char argname[15]; + struct ast_var_t *vardata; + + /* If chan is not defined, then we're calling it as part of gosub_free, + * and the channel variables will be deallocated anyway. Otherwise, we're + * just releasing a single frame, so we need to clean up the arguments for + * that frame, so that we re-expose the variables from the previous frame + * that were hidden by this one. + */ + if (chan) { + for (i = 1; i <= frame->arguments && i != 0; i++) { + snprintf(argname, sizeof(argname), "ARG%hhd", i); + pbx_builtin_setvar_helper(chan, argname, NULL); + } + } + + /* Delete local variables */ + while ((vardata = AST_LIST_REMOVE_HEAD(&frame->varshead, entries))) { + if (chan) + pbx_builtin_setvar_helper(chan, ast_var_name(vardata), NULL); + ast_var_delete(vardata); + } + + ast_free(frame); +} + +static struct gosub_stack_frame *gosub_allocate_frame(const char *context, const char *extension, int priority, unsigned char arguments) +{ + struct gosub_stack_frame *new = NULL; + int len_extension = strlen(extension), len_context = strlen(context); + + if ((new = ast_calloc(1, sizeof(*new) + 2 + len_extension + len_context))) { + AST_LIST_HEAD_INIT_NOLOCK(&new->varshead); + strcpy(new->extension, extension); + new->context = new->extension + len_extension + 1; + strcpy(new->context, context); + new->priority = priority; + new->arguments = arguments; + } + return new; +} + +static void gosub_free(void *data) +{ + AST_LIST_HEAD(, gosub_stack_frame) *oldlist = data; + struct gosub_stack_frame *oldframe; + AST_LIST_LOCK(oldlist); + while ((oldframe = AST_LIST_REMOVE_HEAD(oldlist, entries))) { + gosub_release_frame(NULL, oldframe); + } + AST_LIST_UNLOCK(oldlist); + AST_LIST_HEAD_DESTROY(oldlist); + ast_free(oldlist); +} + +static int pop_exec(struct ast_channel *chan, void *data) +{ + struct ast_datastore *stack_store = ast_channel_datastore_find(chan, &stack_info, NULL); + struct gosub_stack_frame *oldframe; + AST_LIST_HEAD(, gosub_stack_frame) *oldlist; + + if (!stack_store) { + ast_log(LOG_WARNING, "%s called with no gosub stack allocated.\n", app_pop); + return 0; + } + + oldlist = stack_store->data; + AST_LIST_LOCK(oldlist); + oldframe = AST_LIST_REMOVE_HEAD(oldlist, entries); + AST_LIST_UNLOCK(oldlist); + + if (oldframe) { + gosub_release_frame(chan, oldframe); + } else { + ast_debug(1, "%s called with an empty gosub stack\n", app_pop); + } + return 0; +} + +static int return_exec(struct ast_channel *chan, void *data) +{ + struct ast_datastore *stack_store = ast_channel_datastore_find(chan, &stack_info, NULL); + struct gosub_stack_frame *oldframe; + AST_LIST_HEAD(, gosub_stack_frame) *oldlist; + char *retval = data; + + if (!stack_store) { + ast_log(LOG_ERROR, "Return without Gosub: stack is unallocated\n"); + return -1; + } + + oldlist = stack_store->data; + AST_LIST_LOCK(oldlist); + oldframe = AST_LIST_REMOVE_HEAD(oldlist, entries); + AST_LIST_UNLOCK(oldlist); + + if (!oldframe) { + ast_log(LOG_ERROR, "Return without Gosub: stack is empty\n"); + return -1; + } + + ast_explicit_goto(chan, oldframe->context, oldframe->extension, oldframe->priority); + gosub_release_frame(chan, oldframe); + + /* Set a return value, if any */ + pbx_builtin_setvar_helper(chan, "GOSUB_RETVAL", S_OR(retval, "")); + return 0; +} + +static int gosub_exec(struct ast_channel *chan, void *data) +{ + struct ast_datastore *stack_store = ast_channel_datastore_find(chan, &stack_info, NULL); + AST_LIST_HEAD(, gosub_stack_frame) *oldlist; + struct gosub_stack_frame *newframe; + char argname[15], *tmp = ast_strdupa(data), *label, *endparen; + int i; + AST_DECLARE_APP_ARGS(args2, + AST_APP_ARG(argval)[100]; + ); + + if (ast_strlen_zero(data)) { + ast_log(LOG_ERROR, "%s requires an argument: %s([[context|]exten|]priority[(arg1[|...][|argN])])\n", app_gosub, app_gosub); + return -1; + } + + if (!stack_store) { + ast_debug(1, "Channel %s has no datastore, so we're allocating one.\n", chan->name); + stack_store = ast_channel_datastore_alloc(&stack_info, NULL); + if (!stack_store) { + ast_log(LOG_ERROR, "Unable to allocate new datastore. Gosub will fail.\n"); + return -1; + } + + oldlist = ast_calloc(1, sizeof(*oldlist)); + if (!oldlist) { + ast_log(LOG_ERROR, "Unable to allocate datastore list head. Gosub will fail.\n"); + ast_channel_datastore_free(stack_store); + return -1; + } + + stack_store->data = oldlist; + AST_LIST_HEAD_INIT(oldlist); + ast_channel_datastore_add(chan, stack_store); + } + + /* Separate the arguments from the label */ + /* NOTE: you cannot use ast_app_separate_args for this, because '(' cannot be used as a delimiter. */ + label = strsep(&tmp, "("); + if (tmp) { + endparen = strrchr(tmp, ')'); + if (endparen) + *endparen = '\0'; + else + ast_log(LOG_WARNING, "Ouch. No closing paren: '%s'?\n", (char *)data); + AST_STANDARD_APP_ARGS(args2, tmp); + } else + args2.argc = 0; + + /* Create the return address, but don't save it until we know that the Gosub destination exists */ + newframe = gosub_allocate_frame(chan->context, chan->exten, chan->priority + 1, args2.argc); + + if (!newframe) + return -1; + + if (ast_parseable_goto(chan, label)) { + ast_log(LOG_ERROR, "Gosub address is invalid: '%s'\n", (char *)data); + ast_free(newframe); + return -1; + } + + /* Now that we know for certain that we're going to a new location, set our arguments */ + for (i = 0; i < args2.argc; i++) { + snprintf(argname, sizeof(argname), "ARG%d", i + 1); + frame_set_var(chan, newframe, argname, args2.argval[i]); + ast_debug(1, "Setting '%s' to '%s'\n", argname, args2.argval[i]); + } + + /* And finally, save our return address */ + oldlist = stack_store->data; + AST_LIST_LOCK(oldlist); + AST_LIST_INSERT_HEAD(oldlist, newframe, entries); + AST_LIST_UNLOCK(oldlist); + + return 0; +} + +static int gosubif_exec(struct ast_channel *chan, void *data) +{ + char *args; + int res=0; + AST_DECLARE_APP_ARGS(cond, + AST_APP_ARG(ition); + AST_APP_ARG(labels); + ); + AST_DECLARE_APP_ARGS(label, + AST_APP_ARG(iftrue); + AST_APP_ARG(iffalse); + ); + + if (ast_strlen_zero(data)) { + ast_log(LOG_WARNING, "GosubIf requires an argument: GosubIf(cond?label1(args):label2(args)\n"); + return 0; + } + + args = ast_strdupa(data); + AST_NONSTANDARD_APP_ARGS(cond, args, '?'); + if (cond.argc != 2) { + ast_log(LOG_WARNING, "GosubIf requires an argument: GosubIf(cond?label1(args):label2(args)\n"); + return 0; + } + + AST_NONSTANDARD_APP_ARGS(label, cond.labels, ':'); + + if (pbx_checkcondition(cond.ition)) { + if (!ast_strlen_zero(label.iftrue)) + res = gosub_exec(chan, label.iftrue); + } else if (!ast_strlen_zero(label.iffalse)) { + res = gosub_exec(chan, label.iffalse); + } + + return res; +} + +static int local_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len) +{ + struct ast_datastore *stack_store = ast_channel_datastore_find(chan, &stack_info, NULL); + AST_LIST_HEAD(, gosub_stack_frame) *oldlist; + struct gosub_stack_frame *frame; + struct ast_var_t *variables; + + if (!stack_store) + return -1; + + oldlist = stack_store->data; + AST_LIST_LOCK(oldlist); + frame = AST_LIST_FIRST(oldlist); + AST_LIST_TRAVERSE(&frame->varshead, variables, entries) { + if (!strcmp(data, ast_var_name(variables))) { + const char *tmp = pbx_builtin_getvar_helper(chan, data); + ast_copy_string(buf, S_OR(tmp, ""), len); + break; + } + } + AST_LIST_UNLOCK(oldlist); + return 0; +} + +static int local_write(struct ast_channel *chan, const char *cmd, char *var, const char *value) +{ + struct ast_datastore *stack_store = ast_channel_datastore_find(chan, &stack_info, NULL); + AST_LIST_HEAD(, gosub_stack_frame) *oldlist; + struct gosub_stack_frame *frame; + + if (!stack_store) { + ast_log(LOG_ERROR, "Tried to set LOCAL(%s), but we aren't within a Gosub routine\n", var); + return -1; + } + + oldlist = stack_store->data; + AST_LIST_LOCK(oldlist); + frame = AST_LIST_FIRST(oldlist); + + if (frame) + frame_set_var(chan, frame, var, value); + + AST_LIST_UNLOCK(oldlist); + + return 0; +} + +static struct ast_custom_function local_function = { + .name = "LOCAL", + .synopsis = "Variables local to the gosub stack frame", + .syntax = "LOCAL(<varname>)", + .write = local_write, + .read = local_read, +}; + +static int unload_module(void) +{ + ast_unregister_application(app_return); + ast_unregister_application(app_pop); + ast_unregister_application(app_gosubif); + ast_unregister_application(app_gosub); + ast_custom_function_unregister(&local_function); + + return 0; +} + +static int load_module(void) +{ + ast_register_application(app_pop, pop_exec, pop_synopsis, pop_descrip); + ast_register_application(app_return, return_exec, return_synopsis, return_descrip); + ast_register_application(app_gosubif, gosubif_exec, gosubif_synopsis, gosubif_descrip); + ast_register_application(app_gosub, gosub_exec, gosub_synopsis, gosub_descrip); + ast_custom_function_register(&local_function); + + return 0; +} + +AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Dialplan subroutines (Gosub, Return, etc)"); |