Merge HINT() dialplan function from my sandbox branch into trunk. This function

will let you retrieve the list of devices or name associated with a hint.
(inspired by issue #10635)


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@81783 f38db490-d61c-443f-a65b-d21fe96a405b

CHANGES

@@ -38,6 +38,10 @@ Dialplan functions
     mutex.  No deadlocks are possible, as LOCK() only allows a single lock to be
     held for any given channel.  Also, locks are automatically freed when a
     channel is hung up.
+  * Added HINT() dialplan function that allows retrieving hint information.
+    Hints are mappings between extensions and devices for the sake of 
+    determining the state of an extension.  This function can retrieve the list
+    of devices or the name associated with a hint.
 
 CLI Changes
 -----------

funcs/func_devstate.c

@@ -42,6 +42,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #include "asterisk/devicestate.h"
 #include "asterisk/cli.h"
 #include "asterisk/astdb.h"
+#include "asterisk/app.h"
 
 static const char astdb_family[] = "CustomDevstate";
 
@@ -73,6 +74,52 @@ static int devstate_write(struct ast_channel *chan, const char *cmd, char *data,
 	return 0;
 }
 
+enum {
+	HINT_OPT_NAME = (1 << 0),
+};
+
+AST_APP_OPTIONS(hint_options, BEGIN_OPTIONS
+	AST_APP_OPTION('n', HINT_OPT_NAME),
+END_OPTIONS );
+
+static int hint_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
+{
+	char *exten, *context;
+	AST_DECLARE_APP_ARGS(args,
+		AST_APP_ARG(exten);
+		AST_APP_ARG(options);
+	);
+	struct ast_flags opts = { 0, };
+	int res;
+
+	if (ast_strlen_zero(data)) {
+		ast_log(LOG_WARNING, "The HINT function requires an extension\n");
+		return -1;
+	}
+
+	AST_STANDARD_APP_ARGS(args, data);
+
+	if (ast_strlen_zero(args.exten)) {
+		ast_log(LOG_WARNING, "The HINT function requires an extension\n");
+		return -1;
+	}
+
+	context = exten = args.exten;
+	strsep(&context, "@");
+	if (ast_strlen_zero(context))
+		context = "default";
+
+	if (!ast_strlen_zero(args.options))
+		ast_app_parse_options(hint_options, &opts, NULL, args.options);
+
+	if (ast_test_flag(&opts, HINT_OPT_NAME))
+		res = ast_get_hint(NULL, 0, buf, len, chan, context, exten);
+	else
+		res = ast_get_hint(buf, len, NULL, 0, chan, context, exten);
+
+	return !res; /* ast_get_hint returns non-zero on success */
+}
+
 static enum ast_device_state custom_devstate_callback(const char *data)
 {
 	char buf[256] = "";
@@ -155,11 +202,26 @@ static struct ast_custom_function devstate_function = {
 	.write = devstate_write,
 };
 
+static struct ast_custom_function hint_function = {
+	.name = "HINT",
+	.synopsis = "Get the devices set for a dialplan hint",
+	.syntax = "HINT(extension[@context][|options])",
+	.desc =
+	"  The HINT function can be used to retrieve the list of devices that are\n"
+	"mapped to a dialplan hint.  For example:\n"
+	"   NoOp(Hint for Extension 1234 is ${HINT(1234)})\n"
+	"Options:\n"
+	"   'n' - Retrieve name on the hint instead of list of devices\n"
+	"",
+	.read = hint_read,
+};
+
 static int unload_module(void)
 {
 	int res = 0;
 
 	res |= ast_custom_function_unregister(&devstate_function);
+	res |= ast_custom_function_unregister(&hint_function);
 	res |= ast_devstate_prov_del("Custom");
 	res |= ast_cli_unregister_multiple(cli_funcdevstate, ARRAY_LEN(cli_funcdevstate));
 
@@ -185,6 +247,7 @@ static int load_module(void)
 	db_tree = NULL;
 
 	res |= ast_custom_function_register(&devstate_function);
+	res |= ast_custom_function_register(&hint_function);
 	res |= ast_devstate_prov_add("Custom", custom_devstate_callback);
 	res |= ast_cli_register_multiple(cli_funcdevstate, ARRAY_LEN(cli_funcdevstate));