app_waitforcond.c File Reference

Sleep until a condition is true. More...

#include "asterisk.h"
#include "asterisk/logger.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/module.h"
#include "asterisk/app.h"

Include dependency graph for app_waitforcond.c:

Go to the source code of this file.

Functions
	AST_MODULE_INFO_STANDARD_EXTENDED (ASTERISK_GPL_KEY, "Wait until condition is true")
static int	load_module (void)
static int	unload_module (void)
static int	waitforcond_exec (struct ast_channel *chan, const char *data)

Variables
static char *	app = "WaitForCondition"

Detailed Description

Sleep until a condition is true.

Author

Naveen Albert aster.nosp@m.isk@.nosp@m.phrea.nosp@m.knet.nosp@m..org

Definition in file app_waitforcond.c.

Function Documentation

AST_MODULE_INFO_STANDARD_EXTENDED()

AST_MODULE_INFO_STANDARD_EXTENDED	(	ASTERISK_GPL_KEY	,
		"Wait until condition is true"
	)

load_module()

static int load_module ( void  )

static

Definition at line 233 of file app_waitforcond.c.

{
    return ast_register_application_xml(app, waitforcond_exec);
}

References app, ast_register_application_xml, and waitforcond_exec().

unload_module()

static int unload_module ( void  )

static

Definition at line 228 of file app_waitforcond.c.

{
    return ast_unregister_application(app);
}

References app, and ast_unregister_application().

waitforcond_exec()

static int waitforcond_exec ( struct ast_channel *  chan, const char *  data  )

static

Definition at line 99 of file app_waitforcond.c.

{
    int ms, i;
    double timeout = 0, poll = 0;
    int timeout_ms = 0;
    int poll_ms = 50; /* default is evaluate the condition every 50ms */
    struct timeval start = ast_tvnow();
    char dollarsignrep;
    int brackets = 0;
    char *pos, *open_bracket, *expression, *optargs = NULL;
    char condition[512];
 
    AST_DECLARE_APP_ARGS(args,
        AST_APP_ARG(timeout);
        AST_APP_ARG(interval);
    );
 
    pos = ast_strdupa(data);
 
    if (ast_strlen_zero(pos)) {
        ast_log(LOG_ERROR, "WaitForCondition requires a condition\n");
        pbx_builtin_setvar_helper(chan, "WAITFORCONDITIONSTATUS", "FAILURE");
        return 0;
    }
 
    /* is there at least a [ followed by a ] somewhere ? */
    if (!(open_bracket = strchr(pos, '[')) || !strchr(open_bracket, ']')) {
        ast_log(LOG_ERROR, "No expression detected. Did you forget to replace the $ signs?\n");
        pbx_builtin_setvar_helper(chan, "WAITFORCONDITIONSTATUS", "FAILURE");
        return 0;
    }
 
    dollarsignrep = pos[0];
    if (dollarsignrep == '$' || dollarsignrep == '[' || dollarsignrep == ']'
        || dollarsignrep == '{' || dollarsignrep == '}') {
        ast_log(LOG_ERROR, "Dollar sign replacement cannot be %c.\n", dollarsignrep);
        pbx_builtin_setvar_helper(chan, "WAITFORCONDITIONSTATUS", "FAILURE");
        return 0;
    }
    ++pos;
    if (pos[0] != ',') {
        ast_log(LOG_ERROR, "Invalid separator: %c\n", pos[0]);
        pbx_builtin_setvar_helper(chan, "WAITFORCONDITIONSTATUS", "FAILURE");
        return 0;
    }
    ++pos;
    if (pos[0] != dollarsignrep) {
        ast_log(LOG_ERROR, "Expression start does not match provided replacement: %c\n", pos[0]);
        pbx_builtin_setvar_helper(chan, "WAITFORCONDITIONSTATUS", "FAILURE");
        return 0;
    }
 
    expression = pos; /* we're at the start of the expression */
 
    /* commas may appear within the expression, so go until we've encountered as many closing brackets as opening */
    while (++pos) {
        if (pos[0] == '\0') {
            ast_log(LOG_ERROR, "Could not parse end of expression.\n");
            pbx_builtin_setvar_helper(chan, "WAITFORCONDITIONSTATUS", "FAILURE");
            return 0;
        }
        if (pos[0] == '[') {
            brackets++;
        } else if (pos[0] == ']') {
            brackets--;
        }
        if (brackets == 0) { /* reached end of expression */
            break;
        }
    }
    ++pos;
    if (pos[0] != '\0') {
        ++pos; /* eat comma separator */
        if (pos[0] != '\0') {
            optargs = ast_strdupa(pos);
            AST_STANDARD_APP_ARGS(args, optargs);
            if (!ast_strlen_zero(args.timeout)) {
                if (sscanf(args.timeout, "%30lg", &timeout) != 1) {
                    ast_log(LOG_WARNING, "Invalid timeout provided: %s. No timeout set.\n", args.timeout);
                    return -1;
                }
                timeout_ms = timeout * 1000.0;
            }
 
            if (!ast_strlen_zero(args.interval)) {
                if (sscanf(args.interval, "%30lg", &poll) != 1) {
                    ast_log(LOG_WARNING, "Invalid polling interval provided: %s. Default unchanged.\n", args.interval);
                    return -1;
                }
                if (poll < 0.001) {
                    ast_log(LOG_WARNING, "Polling interval cannot be less than 1ms. Default unchanged.\n");
                    return -1;
                }
                poll_ms = poll * 1000.0;
            }
        }
    }
 
    for (i = 0; expression[i] != '\0'; i++) {
        if (expression[i] == dollarsignrep) {
            expression[i] = '$'; /* replace $s back into expression for variable parsing */
        }
    }
 
    if (timeout_ms > 0) {
        ast_debug(1, "Waiting for condition for %f seconds: %s (checking every %d ms)", timeout, expression, poll_ms);
    } else {
        ast_debug(1, "Waiting for condition, forever: %s (checking every %d ms)", expression, poll_ms);
    }
 
    while (1) {
        /* Substitute variables now */
        pbx_substitute_variables_helper(chan, expression, condition, sizeof(condition) - 1);
        if (pbx_checkcondition(condition)) {
            pbx_builtin_setvar_helper(chan, "WAITFORCONDITIONSTATUS", "TRUE");
            return 0;
        }
        /* If a timeout was specified, check that it hasn't expired */
        if ((timeout_ms > 0) && !(ms = ast_remaining_ms(start, timeout_ms))) {
            pbx_builtin_setvar_helper(chan, "WAITFORCONDITIONSTATUS", "TIMEOUT");
            return 0;
        }
        if (ast_safe_sleep(chan, poll_ms)) { /* don't waste CPU, we don't need a super tight loop */
            pbx_builtin_setvar_helper(chan, "WAITFORCONDITIONSTATUS", "HANGUP");
            return -1; /* channel hung up */
        }
    }
}

References args, AST_APP_ARG, ast_debug, AST_DECLARE_APP_ARGS, ast_log, ast_remaining_ms(), ast_safe_sleep(), AST_STANDARD_APP_ARGS, ast_strdupa, ast_strlen_zero(), ast_tvnow(), LOG_ERROR, LOG_WARNING, NULL, pbx_builtin_setvar_helper(), pbx_checkcondition(), and pbx_substitute_variables_helper().

Referenced by load_module().

Variable Documentation

app

char* app = "WaitForCondition"

static

Definition at line 97 of file app_waitforcond.c.

Referenced by load_module(), and unload_module().