app_while.c

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright 2004 - 2005, Anthony Minessale <anthmct@yahoo.com>
 *
 * Anthony Minessale <anthmct@yahoo.com>
 *
 * 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 While Loop Implementation
 *
 * \author Anthony Minessale <anthmct@yahoo.com>
 *
 * \ingroup applications
 */
 
/*** MODULEINFO
    <support_level>core</support_level>
 ***/
 
#include "asterisk.h"
 
#include "asterisk/pbx.h"
#include "asterisk/module.h"
#include "asterisk/channel.h"
 
/*** DOCUMENTATION
    <application name="While" language="en_US">
        <since>
            <version>1.2.0</version>
        </since>
        <synopsis>
            Start a while loop.
        </synopsis>
        <syntax>
            <parameter name="expr" required="true" />
        </syntax>
        <description>
            <para>Start a While Loop.  Execution will return to this point when
            <literal>EndWhile()</literal> is called until expr is no longer true.</para>
        </description>
        <see-also>
            <ref type="application">EndWhile</ref>
            <ref type="application">ExitWhile</ref>
            <ref type="application">ContinueWhile</ref>
        </see-also>
    </application>
    <application name="EndWhile" language="en_US">
        <since>
            <version>1.2.0</version>
        </since>
        <synopsis>
            End a while loop.
        </synopsis>
        <syntax />
        <description>
            <para>Return to the previous called <literal>While()</literal>.</para>
        </description>
        <see-also>
            <ref type="application">While</ref>
            <ref type="application">ExitWhile</ref>
            <ref type="application">ContinueWhile</ref>
        </see-also>
    </application>
    <application name="ExitWhile" language="en_US">
        <since>
            <version>1.4.0</version>
        </since>
        <synopsis>
            End a While loop.
        </synopsis>
        <syntax />
        <description>
            <para>Exits a <literal>While()</literal> loop, whether or not the conditional has been satisfied.</para>
        </description>
        <see-also>
            <ref type="application">While</ref>
            <ref type="application">EndWhile</ref>
            <ref type="application">ContinueWhile</ref>
        </see-also>
    </application>
    <application name="ContinueWhile" language="en_US">
        <since>
            <version>1.4.0</version>
        </since>
        <synopsis>
            Restart a While loop.
        </synopsis>
        <syntax />
        <description>
            <para>Returns to the top of the while loop and re-evaluates the conditional.</para>
        </description>
        <see-also>
            <ref type="application">While</ref>
            <ref type="application">EndWhile</ref>
            <ref type="application">ExitWhile</ref>
        </see-also>
    </application>
 ***/
 
static char *start_app = "While";
static char *stop_app = "EndWhile";
static char *exit_app = "ExitWhile";
static char *continue_app = "ContinueWhile";
 
#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_endwhile(struct ast_channel *chan)
{
    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), "WHILE")) {
                        level++;
                    } else if (!strcasecmp(ast_get_extension_app(e), "ENDWHILE")) {
                        level--;
                    }
 
                    if (level == 0) {
                        res = cur_priority;
                        break;
                    }
                }
            }
            ast_unlock_context(c);
            if (res > 0) {
                break;
            }
        }
    }
    ast_unlock_contexts();
    return res;
}
 
static int _while_exec(struct ast_channel *chan, const char *data, int end)
{
    int res=0;
    const char *while_pri = NULL;
    char *my_name = NULL;
    const char *condition = NULL, *label = NULL;
    char varname[VAR_SIZE], end_varname[VAR_SIZE];
    const char *prefix = "WHILE";
    size_t size=0;
    int used_index_i = -1, x=0;
    char used_index[VAR_SIZE] = "0", new_index[VAR_SIZE] = "0";
 
    if (!chan) {
        /* huh ? */
        return -1;
    }
 
#if 0
    /* don't want run away loops if the chan isn't even up
       this is up for debate since it slows things down a tad ......
 
       Debate is over... this prevents While/EndWhile from working
       within the "h" extension.  Not good.
    */
    if (ast_waitfordigit(chan,1) < 0)
        return -1;
#endif
 
    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);
 
    if (!end)
        condition = ast_strdupa(data);
 
    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) {
        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, VAR_SIZE, "%s_%s", prefix, label);
    if ((while_pri = pbx_builtin_getvar_helper(chan, varname)) && !end) {
        while_pri = ast_strdupa(while_pri);
        snprintf(end_varname,VAR_SIZE,"END_%s",varname);
    }
    ast_channel_unlock(chan);
 
 
    if ((!end && !pbx_checkcondition(condition)) || (end == 2)) {
        /* Condition Met (clean up helper vars) */
        const char *goto_str;
        pbx_builtin_setvar_helper(chan, varname, NULL);
        pbx_builtin_setvar_helper(chan, my_name, NULL);
        snprintf(end_varname,VAR_SIZE,"END_%s",varname);
        ast_channel_lock(chan);
        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 {
            int pri = find_matching_endwhile(chan);
            if (pri > 0) {
                ast_verb(3, "Jumping to priority %d\n", pri);
                ast_channel_priority_set(chan, pri);
            } else {
                ast_log(LOG_WARNING, "Couldn't find matching EndWhile? (While 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 && !while_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 && while_pri) {
        /* END of loop */
        snprintf(end_varname, VAR_SIZE, "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, while_pri);
    }
 
    return res;
}
 
static int while_start_exec(struct ast_channel *chan, const char *data) {
    return _while_exec(chan, data, 0);
}
 
static int while_end_exec(struct ast_channel *chan, const char *data) {
    return _while_exec(chan, data, 1);
}
 
static int while_exit_exec(struct ast_channel *chan, const char *data) {
    return _while_exec(chan, data, 2);
}
 
static int while_continue_exec(struct ast_channel *chan, const char *data)
{
    int x;
    const char *prefix = "WHILE", *while_pri=NULL;
 
    for (x = 0; ; x++) {
        const char *tmp = get_index(chan, prefix, x);
        if (tmp)
            while_pri = tmp;
        else
            break;
    }
 
    if (while_pri)
        ast_parseable_goto(chan, while_pri);
 
    return 0;
}
 
static int unload_module(void)
{
    int res;
 
    res = ast_unregister_application(start_app);
    res |= ast_unregister_application(stop_app);
    res |= ast_unregister_application(exit_app);
    res |= ast_unregister_application(continue_app);
 
    return res;
}
 
static int load_module(void)
{
    int res;
 
    res = ast_register_application_xml(start_app, while_start_exec);
    res |= ast_register_application_xml(stop_app, while_end_exec);
    res |= ast_register_application_xml(exit_app, while_exit_exec);
    res |= ast_register_application_xml(continue_app, while_continue_exec);
 
    return res;
}
 
AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "While Loops and Conditional Execution");