Break res_stasis into smaller files.

When implementing playback for stasis-http, the monolithicedness of
res_stasis really started to get in my way.

This patch breaks the major components of res_stasis.c into individual
files.

 * res/stasis/app.c - Stasis application tracking
 * res/stasis/control.c - Channel control objects
 * res/stasis/command.c - Channel command object

This refactoring also allows res_stasis applications to be loaded as
independent modules, such as the new res_stasis_answer module.

The bulk of this patch is simply moving code from one file to another,
adjusting names and adding accessors as necessary.

Review: https://reviewboard.asterisk.org/r/2530/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@388729 65c4cc65-6c06-0410-ace0-fbb531ad65f3

9 files changed, 847 insertions, 418 deletions

diff --git a/res/Makefile b/res/Makefile
index 35d09275c..2ed719093 100644
--- a/res/Makefile
+++ b/res/Makefile
@@ -46,6 +46,9 @@ ael/ael_lex.o ael/ael.tab.o ael/pval.o: _ASTCFLAGS+=$(call MOD_ASTCFLAGS,res_ael
 $(if $(filter res_sip,$(EMBEDDED_MODS)),modules.link,res_sip.so): $(subst .c,.o,$(wildcard res_sip/*.c))
 $(subst .c,.o,$(wildcard res_sip/*.c)): _ASTCFLAGS+=$(call MOD_ASTCFLAGS,res_sip)
 
+$(if $(filter res_stasis,$(EMBEDDED_MODS)),modules.link,res_stasis.so): $(subst .c,.o,$(wildcard stasis/*.c))
+$(subst .c,.o,$(wildcard stasis/*.c)): _ASTCFLAGS+=$(call MOD_ASTCFLAGS,res_stasis)
+
 ifneq ($(findstring REBUILD_PARSERS,$(MENUSELECT_CFLAGS)),)
 ael/ael_lex.c: ael/ael.flex
 else
@@ -70,7 +73,8 @@ endif
 ael/pval.o: ael/pval.c
 
 clean::
-	rm -f snmp/*.[oi] ael/*.[oi] ais/*.[oi] stasis_http/*.[oi] res_sip/*.[oi]
+	rm -f snmp/*.[oi] ael/*.[oi] ais/*.[oi] stasis_http/*.[oi]
+	rm -f res_sip/*.[oi] stasis/*.[oi]
 
 # Dependencies for res_stasis_http_*.so are generated, so they're in this file
 include stasis_http.make
diff --git a/res/res_stasis.c b/res/res_stasis.c
index 4a11680fb..5327ca4ac 100644
--- a/res/res_stasis.c
+++ b/res/res_stasis.c
@@ -21,6 +21,30 @@
  * \brief Stasis application support.
  *
  * \author David M. Lee, II <dlee@digium.com>
+ *
+ * <code>res_stasis.so</code> brings together the various components of the
+ * Stasis application infrastructure.
+ *
+ * First, there's the Stasis application handler, stasis_app_exec(). This is
+ * called by <code>app_stasis.so</code> to give control of a channel to the
+ * Stasis application code from the dialplan.
+ *
+ * While a channel is in stasis_app_exec(), it has a \ref stasis_app_control
+ * object, which may be used to control the channel.
+ *
+ * To control the channel, commands may be sent to channel using
+ * stasis_app_send_command() and stasis_app_send_async_command().
+ *
+ * Alongside this, applications may be registered/unregistered using
+ * stasis_app_register()/stasis_app_unregister(). While a channel is in Stasis,
+ * events received on the channel's topic are converted to JSON and forwarded to
+ * the \ref stasis_app_cb. The application may also subscribe to the channel to
+ * continue to receive messages even after the channel has left Stasis, but it
+ * will not be able to control it.
+ *
+ * Given all the stuff that comes together in this module, it's been broken up
+ * into several pieces that are in <code>res/stasis/</code> and compiled into
+ * <code>res_stasis.so</code>.
  */
 
 /*** MODULEINFO
@@ -33,15 +57,14 @@
 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 
 #include "asterisk/astobj2.h"
-#include "asterisk/channel.h"
-#include "asterisk/lock.h"
+#include "asterisk/callerid.h"
 #include "asterisk/module.h"
-#include "asterisk/stasis.h"
-#include "asterisk/stasis_app.h"
+#include "asterisk/stasis_app_impl.h"
 #include "asterisk/stasis_channels.h"
-#include "asterisk/strings.h"
 #include "asterisk/stasis_message_router.h"
-#include "asterisk/callerid.h"
+#include "asterisk/strings.h"
+#include "stasis/app.h"
+#include "stasis/control.h"
 #include "stasis_json/resource_events.h"
 
 /*! Time to wait for a frame in the application */
@@ -60,97 +83,26 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
 #define CONTROLS_NUM_BUCKETS 127
 
 /*!
- * \brief Number of buckets for the channels container for app instances.  Remember
- * to keep it a prime number!
- */
-#define APP_CHANNELS_BUCKETS 7
-
-/*!
  * \brief Number of buckets for the blob_handlers container.  Remember to keep
  * it a prime number!
  */
 #define BLOB_HANDLER_BUCKETS 7
 
 /*!
- * \brief Stasis application container. Please call apps_registry() instead of
- * directly accessing.
+ * \brief Stasis application container.
  */
-struct ao2_container *__apps_registry;
+struct ao2_container *apps_registry;
 
-struct ao2_container *__app_controls;
+struct ao2_container *app_controls;
 
 /*! \brief Message router for the channel caching topic */
 struct stasis_message_router *channel_router;
 
-/*! Ref-counting accessor for the stasis applications container */
-static struct ao2_container *apps_registry(void)
-{
-	ao2_ref(__apps_registry, +1);
-	return __apps_registry;
-}
-
-static struct ao2_container *app_controls(void)
-{
-	ao2_ref(__app_controls, +1);
-	return __app_controls;
-}
-
-struct app {
-	/*! Callback function for this application. */
-	stasis_app_cb handler;
-	/*! Opaque data to hand to callback function. */
-	void *data;
-	/*! List of channel identifiers this app instance is interested in */
-	struct ao2_container *channels;
-	/*! Name of the Stasis application */
-	char name[];
-};
-
-static void app_dtor(void *obj)
-{
-	struct app *app = obj;
-
-	ao2_cleanup(app->data);
-	app->data = NULL;
-	ao2_cleanup(app->channels);
-	app->channels = NULL;
-}
-
-/*! Constructor for \ref app. */
-static struct app *app_create(const char *name, stasis_app_cb handler, void *data)
-{
-	RAII_VAR(struct app *, app, NULL, ao2_cleanup);
-	size_t size;
-
-	ast_assert(name != NULL);
-	ast_assert(handler != NULL);
-
-	size = sizeof(*app) + strlen(name) + 1;
-	app = ao2_alloc_options(size, app_dtor, AO2_ALLOC_OPT_LOCK_MUTEX);
-
-	if (!app) {
-		return NULL;
-	}
-
-	strncpy(app->name, name, size - sizeof(*app));
-	app->handler = handler;
-	ao2_ref(data, +1);
-	app->data = data;
-
-	app->channels = ast_str_container_alloc(APP_CHANNELS_BUCKETS);
-	if (!app->channels) {
-		return NULL;
-	}
-
-	ao2_ref(app, +1);
-	return app;
-}
-
 /*! AO2 hash function for \ref app */
 static int app_hash(const void *obj, const int flags)
 {
 	const struct app *app = obj;
-	const char *name = flags & OBJ_KEY ? obj : app->name;
+	const char *name = flags & OBJ_KEY ? obj : app_name(app);
 
 	return ast_str_hash(name);
 }
@@ -160,149 +112,22 @@ static int app_compare(void *lhs, void *rhs, int flags)
 {
 	const struct app *lhs_app = lhs;
 	const struct app *rhs_app = rhs;
-	const char *rhs_name = flags & OBJ_KEY ? rhs : rhs_app->name;
+	const char *lhs_name = app_name(lhs_app);
+	const char *rhs_name = flags & OBJ_KEY ? rhs : app_name(rhs_app);
 
-	if (strcmp(lhs_app->name, rhs_name) == 0) {
+	if (strcmp(lhs_name, rhs_name) == 0) {
 		return CMP_MATCH | CMP_STOP;
 	} else {
 		return 0;
 	}
 }
 
-static int app_add_channel(struct app* app, const struct ast_channel *chan)
-{
-	const char *uniqueid;
-	ast_assert(chan != NULL);
-	ast_assert(app != NULL);
-
-	uniqueid = ast_channel_uniqueid(chan);
-	if (!ast_str_container_add(app->channels, uniqueid)) {
-		return -1;
-	}
-	return 0;
-}
-
-static void app_remove_channel(struct app* app, const struct ast_channel *chan)
-{
-	ast_assert(chan != NULL);
-	ast_assert(app != NULL);
-
-	ao2_find(app->channels, ast_channel_uniqueid(chan), OBJ_KEY | OBJ_NODATA | OBJ_UNLINK);
-}
-
-/*!
- * \brief Send a message to the given application.
- * \param app App to send the message to.
- * \param message Message to send.
- */
-static void app_send(struct app *app, struct ast_json *message)
-{
-	app->handler(app->data, app->name, message);
-}
-
-typedef void* (*stasis_app_command_cb)(struct stasis_app_control *control,
-				       struct ast_channel *chan,
-				       void *data);
-
-struct stasis_app_command {
-	ast_mutex_t lock;
-	ast_cond_t condition;
-	stasis_app_command_cb callback;
-	void *data;
-	void *retval;
-	int is_done:1;
-};
-
-static void command_dtor(void *obj)
-{
-	struct stasis_app_command *command = obj;
-	ast_mutex_destroy(&command->lock);
-	ast_cond_destroy(&command->condition);
-}
-
-static struct stasis_app_command *command_create(stasis_app_command_cb callback,
-						 void *data)
-{
-	RAII_VAR(struct stasis_app_command *, command, NULL, ao2_cleanup);
-
-	command = ao2_alloc(sizeof(*command), command_dtor);
-	if (!command) {
-		return NULL;
-	}
-
-	ast_mutex_init(&command->lock);
-	ast_cond_init(&command->condition, 0);
-	command->callback = callback;
-	command->data = data;
-
-	ao2_ref(command, +1);
-	return command;
-}
-
-static void command_complete(struct stasis_app_command *command, void *retval)
-{
-	SCOPED_MUTEX(lock, &command->lock);
-
-	command->is_done = 1;
-	command->retval = retval;
-	ast_cond_signal(&command->condition);
-}
-
-static void *wait_for_command(struct stasis_app_command *command)
-{
-	SCOPED_MUTEX(lock, &command->lock);
-	while (!command->is_done) {
-		ast_cond_wait(&command->condition, &command->lock);
-	}
-
-	return command->retval;
-}
-
-struct stasis_app_control {
-	/*! Queue of commands to dispatch on the channel */
-	struct ao2_container *command_queue;
-	/*!
-	 * When set, /c app_stasis should exit and continue in the dialplan.
-	 */
-	int continue_to_dialplan:1;
-	/*! Uniqueid of the associated channel */
-	char channel_id[];
-};
-
-static struct stasis_app_control *control_create(const char *uniqueid)
-{
-	struct stasis_app_control *control;
-	size_t size;
-
-	size = sizeof(*control) + strlen(uniqueid) + 1;
-	control = ao2_alloc(size, NULL);
-	if (!control) {
-		return NULL;
-	}
-
-	control->command_queue = ao2_container_alloc_list(0, 0, NULL, NULL);
-
-	strncpy(control->channel_id, uniqueid, size - sizeof(*control));
-
-	return control;
-}
-
-static void *exec_command(struct stasis_app_control *control,
-			  struct stasis_app_command *command)
-{
-	ao2_lock(control);
-	ao2_ref(command, +1);
-	ao2_link(control->command_queue, command);
-	ao2_unlock(control);
-
-	return wait_for_command(command);
-}
-
 /*! AO2 hash function for \ref stasis_app_control */
 static int control_hash(const void *obj, const int flags)
 {
 	const struct stasis_app_control *control = obj;
-	const char *id = flags & OBJ_KEY ? obj : control->channel_id;
+	const char *id = flags & OBJ_KEY ?
+		obj : stasis_app_control_get_channel_id(control);
 
 	return ast_str_hash(id);
 }
@@ -312,10 +137,11 @@ static int control_compare(void *lhs, void *rhs, int flags)
 {
 	const struct stasis_app_control *lhs_control = lhs;
 	const struct stasis_app_control *rhs_control = rhs;
-	const char *rhs_name =
-		flags & OBJ_KEY ? rhs : rhs_control->channel_id;
+	const char *lhs_id = stasis_app_control_get_channel_id(lhs_control);
+	const char *rhs_id = flags & OBJ_KEY ?
+		rhs : stasis_app_control_get_channel_id(rhs_control);
 
-	if (strcmp(lhs_control->channel_id, rhs_name) == 0) {
+	if (strcmp(lhs_id, rhs_id) == 0) {
 		return CMP_MATCH | CMP_STOP;
 	} else {
 		return 0;
@@ -336,154 +162,30 @@ struct stasis_app_control *stasis_app_control_find_by_channel(
 struct stasis_app_control *stasis_app_control_find_by_channel_id(
 	const char *channel_id)
 {
-	RAII_VAR(struct ao2_container *, controls, NULL, ao2_cleanup);
-	controls = app_controls();
-	return ao2_find(controls, channel_id, OBJ_KEY);
-}
-
-/*!
- * \brief Test the \c continue_to_dialplan bit for the given \a app.
- *
- * The bit is also reset for the next call.
- *
- * \param app Application to check the \c continue_to_dialplan bit.
- * \return Zero to remain in \c Stasis
- * \return Non-zero to continue in the dialplan
- */
-static int control_continue_test_and_reset(struct stasis_app_control *control)
-{
-	int r;
-	SCOPED_AO2LOCK(lock, control);
-
-	r = control->continue_to_dialplan;
-	control->continue_to_dialplan = 0;
-	return r;
-}
-
-void stasis_app_control_continue(struct stasis_app_control *control)
-{
-	SCOPED_AO2LOCK(lock, control);
-	control->continue_to_dialplan = 1;
+	return ao2_find(app_controls, channel_id, OBJ_KEY);
 }
 
 /*! \brief Typedef for blob handler callbacks */
 typedef struct ast_json *(*channel_blob_handler_cb)(struct ast_channel_blob *);
 
-static int OK = 0;
-static int FAIL = -1;
-
-static void *__app_control_answer(struct stasis_app_control *control,
-				  struct ast_channel *chan, void *data)
-{
-	ast_debug(3, "%s: Answering", control->channel_id);
-	return __ast_answer(chan, 0, 1) == 0 ? &OK : &FAIL;
-}
-
-int stasis_app_control_answer(struct stasis_app_control *control)
-{
-	RAII_VAR(struct stasis_app_command *, command, NULL, ao2_cleanup);
-	int *retval;
-
-	ast_debug(3, "%s: Sending answer command\n", control->channel_id);
-
-	command = command_create(__app_control_answer, NULL);
-	retval = exec_command(control, command);
-
-	if (*retval != 0) {
-		ast_log(LOG_WARNING, "Failed to answer channel");
-	}
-
-	return *retval;
-}
-
-static int send_start_msg(struct app *app, struct ast_channel *chan,
-			  int argc, char *argv[])
-{
-	RAII_VAR(struct ast_json *, msg, NULL, ast_json_unref);
-	RAII_VAR(struct ast_json *, blob, NULL, ast_json_unref);
-	RAII_VAR(struct ast_channel_snapshot *, snapshot, NULL, ao2_cleanup);
-
-	struct ast_json *json_args;
-	int i;
-
-	ast_assert(chan != NULL);
-
-	/* Set channel info */
-	snapshot = ast_channel_snapshot_create(chan);
-	if (!snapshot) {
-		return -1;
-	}
-
-	blob = ast_json_pack("{s: []}", "args");
-	if (!blob) {
-		return -1;
-	}
-
-	/* Append arguments to args array */
-	json_args = ast_json_object_get(blob, "args");
-	ast_assert(json_args != NULL);
-	for (i = 0; i < argc; ++i) {
-		int r = ast_json_array_append(json_args,
-					      ast_json_string_create(argv[i]));
-		if (r != 0) {
-			ast_log(LOG_ERROR, "Error appending start message\n");
-			return -1;
-		}
-	}
-
-	msg = stasis_json_event_stasis_start_create(snapshot, blob);
-	if (!msg) {
-		return -1;
-	}
-
-	app_send(app, msg);
-	return 0;
-}
-
-static int send_end_msg(struct app *app, struct ast_channel *chan)
-{
-	RAII_VAR(struct ast_json *, msg, NULL, ast_json_unref);
-	RAII_VAR(struct ast_channel_snapshot *, snapshot, NULL, ao2_cleanup);
-
-	ast_assert(chan != NULL);
-
-	/* Set channel info */
-	snapshot = ast_channel_snapshot_create(chan);
-	if (snapshot == NULL) {
-		return -1;
-	}
-
-	msg = stasis_json_event_stasis_end_create(snapshot);
-	if (!msg) {
-		return -1;
-	}
-
-	app_send(app, msg);
-	return 0;
-}
-
 static int app_watching_channel_cb(void *obj, void *arg, int flags)
 {
-	RAII_VAR(char *, uniqueid, NULL, ao2_cleanup);
 	struct app *app = obj;
-	char *chan_uniqueid = arg;
+	char *uniqueid = arg;
 
-	uniqueid = ao2_find(app->channels, chan_uniqueid, OBJ_KEY);
-	return uniqueid ? CMP_MATCH : 0;
+	return app_is_watching_channel(app, uniqueid) ? CMP_MATCH : 0;
 }
 
 static struct ao2_container *get_watching_apps(const char *uniqueid)
 {
-	RAII_VAR(struct ao2_container *, apps, apps_registry(), ao2_cleanup);
 	struct ao2_container *watching_apps;
 	char *uniqueid_dup;
 	RAII_VAR(struct ao2_iterator *,watching_apps_iter, NULL, ao2_iterator_destroy);
 	ast_assert(uniqueid != NULL);
-	ast_assert(apps != NULL);
 
 	uniqueid_dup = ast_strdupa(uniqueid);
 
-	watching_apps_iter = ao2_callback(apps, OBJ_MULTIPLE, app_watching_channel_cb, uniqueid_dup);
+	watching_apps_iter = ao2_callback(apps_registry, OBJ_MULTIPLE, app_watching_channel_cb, uniqueid_dup);
 	watching_apps = watching_apps_iter->c;
 
 	if (!ao2_container_count(watching_apps)) {
@@ -665,72 +367,111 @@ static void generic_blob_handler(struct ast_channel_blob *obj, channel_blob_hand
  */
 static void control_unlink(struct stasis_app_control *control)
 {
-	RAII_VAR(struct ao2_container *, controls, NULL, ao2_cleanup);
-
 	if (!control) {
 		return;
 	}
 
-	controls = app_controls();
-	ao2_unlink_flags(controls, control,
-			 OBJ_POINTER | OBJ_UNLINK | OBJ_NODATA);
+	ao2_unlink_flags(app_controls, control,
+		OBJ_POINTER | OBJ_UNLINK | OBJ_NODATA);
 	ao2_cleanup(control);
 }
 
-static void dispatch_commands(struct stasis_app_control *control,
-			      struct ast_channel *chan)
+int app_send_start_msg(struct app *app, struct ast_channel *chan,
+	int argc, char *argv[])
 {
-	struct ao2_iterator i;
-	void *obj;
+	RAII_VAR(struct ast_json *, msg, NULL, ast_json_unref);
+	RAII_VAR(struct ast_json *, blob, NULL, ast_json_unref);
+	RAII_VAR(struct ast_channel_snapshot *, snapshot, NULL, ao2_cleanup);
+
+	struct ast_json *json_args;
+	int i;
+
+	ast_assert(chan != NULL);
+
+	/* Set channel info */
+	snapshot = ast_channel_snapshot_create(chan);
+	if (!snapshot) {
+		return -1;
+	}
 
-	SCOPED_AO2LOCK(lock, control);
+	blob = ast_json_pack("{s: []}", "args");
+	if (!blob) {
+		return -1;
+	}
 
-	i = ao2_iterator_init(control->command_queue, AO2_ITERATOR_UNLINK);
+	/* Append arguments to args array */
+	json_args = ast_json_object_get(blob, "args");
+	ast_assert(json_args != NULL);
+	for (i = 0; i < argc; ++i) {
+		int r = ast_json_array_append(json_args,
+					      ast_json_string_create(argv[i]));
+		if (r != 0) {
+			ast_log(LOG_ERROR, "Error appending start message\n");
+			return -1;
+		}
+	}
 
-	while ((obj = ao2_iterator_next(&i))) {
-		RAII_VAR(struct stasis_app_command *, command, obj, ao2_cleanup);
-		void *retval = command->callback(control, chan, command->data);
-		command_complete(command, retval);
+	msg = stasis_json_event_stasis_start_create(snapshot, blob);
+	if (!msg) {
+		return -1;
 	}
 
-	ao2_iterator_destroy(&i);
+	app_send(app, msg);
+	return 0;
 }
 
+int app_send_end_msg(struct app *app, struct ast_channel *chan)
+{
+	RAII_VAR(struct ast_json *, msg, NULL, ast_json_unref);
+	RAII_VAR(struct ast_channel_snapshot *, snapshot, NULL, ao2_cleanup);
+
+	ast_assert(chan != NULL);
+
+	/* Set channel info */
+	snapshot = ast_channel_snapshot_create(chan);
+	if (snapshot == NULL) {
+		return -1;
+	}
+
+	msg = stasis_json_event_stasis_end_create(snapshot);
+	if (!msg) {
+		return -1;
+	}
+
+	app_send(app, msg);
+	return 0;
+}
 
 /*! /brief Stasis dialplan application callback */
 int stasis_app_exec(struct ast_channel *chan, const char *app_name, int argc,
 		    char *argv[])
 {
-	RAII_VAR(struct ao2_container *, apps, apps_registry(), ao2_cleanup);
+	SCOPED_MODULE_USE(ast_module_info->self);
+
 	RAII_VAR(struct app *, app, NULL, ao2_cleanup);
 	RAII_VAR(struct stasis_app_control *, control, NULL, control_unlink);
 	int res = 0;
-	int hungup = 0;
 
 	ast_assert(chan != NULL);
 
-	app = ao2_find(apps, app_name, OBJ_KEY);
+	app = ao2_find(apps_registry, app_name, OBJ_KEY);
 	if (!app) {
 		ast_log(LOG_ERROR,
 			"Stasis app '%s' not registered\n", app_name);
 		return -1;
 	}
 
-	{
-		RAII_VAR(struct ao2_container *, controls, NULL, ao2_cleanup);
-
-		controls = app_controls();
-		control = control_create(ast_channel_uniqueid(chan));
-		if (!control) {
-			ast_log(LOG_ERROR, "Allocated failed\n");
-			return -1;
-		}
-		ao2_link(controls, control);
+	control = control_create(chan);
+	if (!control) {
+		ast_log(LOG_ERROR, "Allocated failed\n");
+		return -1;
 	}
+	ao2_link(app_controls, control);
 
-	res = send_start_msg(app, chan, argc, argv);
+	res = app_send_start_msg(app, chan, argc, argv);
 	if (res != 0) {
-		ast_log(LOG_ERROR, "Error sending start message to %s\n", app_name);
+		ast_log(LOG_ERROR,
+			"Error sending start message to %s\n", app_name);
 		return res;
 	}
 
@@ -739,21 +480,10 @@ int stasis_app_exec(struct ast_channel *chan, const char *app_name, int argc,
 		return -1;
 	}
 
-	while (1) {
+	while (!control_is_done(control)) {
 		RAII_VAR(struct ast_frame *, f, NULL, ast_frame_dtor);
 		int r;
-
-		if (hungup) {
-			ast_debug(3, "%s: Hangup\n",
-				  ast_channel_uniqueid(chan));
-			break;
-		}
-
-		if (control_continue_test_and_reset(control)) {
-			ast_debug(3, "%s: Continue\n",
-				  ast_channel_uniqueid(chan));
-			break;
-		}
+		int command_count;
 
 		r = ast_waitfor(chan, MAX_WAIT_MS);
 
@@ -763,7 +493,12 @@ int stasis_app_exec(struct ast_channel *chan, const char *app_name, int argc,
 			break;
 		}
 
-		dispatch_commands(control, chan);
+		command_count = control_dispatch_all(control, chan);
+
+		if (command_count > 0 && ast_channel_fdno(chan) == -1) {
+			/* Command drained the channel; wait for next frame */
+			continue;
+		}
 
 		if (r == 0) {
 			/* Timeout */
@@ -772,14 +507,19 @@ int stasis_app_exec(struct ast_channel *chan, const char *app_name, int argc,
 
 		f = ast_read(chan);
 		if (!f) {
-			ast_debug(3, "%s: No more frames. Must be done, I guess.\n", ast_channel_uniqueid(chan));
+			ast_debug(3,
+				"%s: No more frames. Must be done, I guess.\n",
+				ast_channel_uniqueid(chan));
 			break;
 		}
 
 		switch (f->frametype) {
 		case AST_FRAME_CONTROL:
 			if (f->subclass.integer == AST_CONTROL_HANGUP) {
-				hungup = 1;
+				/* Continue on in the dialplan */
+				ast_debug(3, "%s: Hangup\n",
+					ast_channel_uniqueid(chan));
+				control_continue(control);
 			}
 			break;
 		default:
@@ -789,7 +529,7 @@ int stasis_app_exec(struct ast_channel *chan, const char *app_name, int argc,
 	}
 
 	app_remove_channel(app, chan);
-	res = send_end_msg(app, chan);
+	res = app_send_end_msg(app, chan);
 	if (res != 0) {
 		ast_log(LOG_ERROR,
 			"Error sending end message to %s\n", app_name);
@@ -801,10 +541,9 @@ int stasis_app_exec(struct ast_channel *chan, const char *app_name, int argc,
 
 int stasis_app_send(const char *app_name, struct ast_json *message)
 {
-	RAII_VAR(struct ao2_container *, apps, apps_registry(), ao2_cleanup);
 	RAII_VAR(struct app *, app, NULL, ao2_cleanup);
 
-	app = ao2_find(apps, app_name, OBJ_KEY);
+	app = ao2_find(apps_registry, app_name, OBJ_KEY);
 
 	if (!app) {
 		/* XXX We can do a better job handling late binding, queueing up
@@ -821,34 +560,29 @@ int stasis_app_send(const char *app_name, struct ast_json *message)
 
 int stasis_app_register(const char *app_name, stasis_app_cb handler, void *data)
 {
-	RAII_VAR(struct ao2_container *, apps, apps_registry(), ao2_cleanup);
 	RAII_VAR(struct app *, app, NULL, ao2_cleanup);
 
-	SCOPED_LOCK(apps_lock, apps, ao2_lock, ao2_unlock);
+	SCOPED_LOCK(apps_lock, apps_registry, ao2_lock, ao2_unlock);
 
-	app = ao2_find(apps, app_name, OBJ_KEY | OBJ_NOLOCK);
+	app = ao2_find(apps_registry, app_name, OBJ_KEY | OBJ_NOLOCK);
 
 	if (app) {
-		RAII_VAR(struct ast_json *, msg, NULL, ast_json_unref);
 		RAII_VAR(struct ast_json *, blob, NULL, ast_json_unref);
-		SCOPED_LOCK(app_lock, app, ao2_lock, ao2_unlock);
+		RAII_VAR(struct ast_json *, msg, NULL, ast_json_unref);
 
 		blob = ast_json_pack("{s: s}", "application", app_name);
 		if (blob) {
 			msg = stasis_json_event_application_replaced_create(blob);
 			if (msg) {
-				app->handler(app->data, app_name, msg);
+				app_send(app, msg);
 			}
 		}
 
-		app->handler = handler;
-		ao2_cleanup(app->data);
-		ao2_ref(data, +1);
-		app->data = data;
+		app_update(app, handler, data);
 	} else {
 		app = app_create(app_name, handler, data);
 		if (app) {
-			ao2_link_flags(apps, app, OBJ_NOLOCK);
+			ao2_link_flags(apps_registry, app, OBJ_NOLOCK);
 		} else {
 			return -1;
 		}
@@ -859,11 +593,9 @@ int stasis_app_register(const char *app_name, stasis_app_cb handler, void *data)
 
 void stasis_app_unregister(const char *app_name)
 {
-	RAII_VAR(struct ao2_container *, apps, NULL, ao2_cleanup);
-
 	if (app_name) {
-		apps = apps_registry();
-		ao2_cleanup(ao2_find(apps, app_name, OBJ_KEY | OBJ_UNLINK));
+		ao2_cleanup(ao2_find(
+				apps_registry, app_name, OBJ_KEY | OBJ_UNLINK));
 	}
 }
 
@@ -957,15 +689,15 @@ static int load_module(void)
 {
 	int r = 0;
 
-	__apps_registry =
+	apps_registry =
 		ao2_container_alloc(APPS_NUM_BUCKETS, app_hash, app_compare);
-	if (__apps_registry == NULL) {
+	if (apps_registry == NULL) {
 		return AST_MODULE_LOAD_FAILURE;
 	}
 
-	__app_controls = ao2_container_alloc(CONTROLS_NUM_BUCKETS,
+	app_controls = ao2_container_alloc(CONTROLS_NUM_BUCKETS,
 					     control_hash, control_compare);
-	if (__app_controls == NULL) {
+	if (app_controls == NULL) {
 		return AST_MODULE_LOAD_FAILURE;
 	}
 
@@ -993,11 +725,11 @@ static int unload_module(void)
 	stasis_message_router_unsubscribe(channel_router);
 	channel_router = NULL;
 
-	ao2_cleanup(__apps_registry);
-	__apps_registry = NULL;
+	ao2_cleanup(apps_registry);
+	apps_registry = NULL;
 
-	ao2_cleanup(__app_controls);
-	__app_controls = NULL;
+	ao2_cleanup(app_controls);
+	app_controls = NULL;
 
 	return r;
 }
diff --git a/res/res_stasis_answer.c b/res/res_stasis_answer.c
new file mode 100644
index 000000000..b7534b93d
--- /dev/null
+++ b/res/res_stasis_answer.c
@@ -0,0 +1,83 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, Digium, Inc.
+ *
+ * David M. Lee, II <dlee@digium.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 Stasis application control support.
+ *
+ * \author David M. Lee, II <dlee@digium.com>
+ */
+
+/*** MODULEINFO
+	<depend type="module">res_stasis</depend>
+	<support_level>core</support_level>
+ ***/
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "asterisk/module.h"
+#include "asterisk/stasis_app_impl.h"
+
+static int OK = 0;
+static int FAIL = -1;
+
+static void *app_control_answer(struct stasis_app_control *control,
+	struct ast_channel *chan, void *data)
+{
+	const int delay = 0;
+	const int cdr_answer = 1;
+	ast_debug(3, "%s: Answering",
+		stasis_app_control_get_channel_id(control));
+	return __ast_answer(chan, delay, cdr_answer) == 0 ? &OK : &FAIL;
+}
+
+int stasis_app_control_answer(struct stasis_app_control *control)
+{
+	int *retval;
+
+	ast_debug(3, "%s: Sending answer command\n",
+		stasis_app_control_get_channel_id(control));
+
+	retval = stasis_app_send_command(control, app_control_answer, NULL);
+
+	if (retval == NULL || *retval != 0) {
+		ast_log(LOG_WARNING, "%s: Failed to answer channel",
+			stasis_app_control_get_channel_id(control));
+		return -1;
+	}
+
+	return 0;
+}
+
+static int load_module(void)
+{
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+static int unload_module(void)
+{
+	return 0;
+}
+
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS,
+	"Stasis application answer support",
+	.load = load_module,
+	.unload = unload_module,
+	.nonoptreq = "res_stasis");
diff --git a/res/stasis/app.c b/res/stasis/app.c
new file mode 100644
index 000000000..d552eb4ab
--- /dev/null
+++ b/res/stasis/app.c
@@ -0,0 +1,142 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, Digium, Inc.
+ *
+ * David M. Lee, II <dlee@digium.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 Stasis application support.
+ *
+ * \author David M. Lee, II <dlee@digium.com>
+ */
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "app.h"
+
+#include "asterisk/stasis_app.h"
+#include "asterisk/stasis_channels.h"
+
+/*!
+ * \brief Number of buckets for the channels container for app instances.  Remember
+ * to keep it a prime number!
+ */
+#define APP_CHANNELS_BUCKETS 7
+
+struct app {
+	/*! Callback function for this application. */
+	stasis_app_cb handler;
+	/*! Opaque data to hand to callback function. */
+	void *data;
+	/*! List of channel identifiers this app instance is interested in */
+	struct ao2_container *channels;
+	/*! Name of the Stasis application */
+	char name[];
+};
+
+static void app_dtor(void *obj)
+{
+	struct app *app = obj;
+
+	ao2_cleanup(app->data);
+	app->data = NULL;
+	ao2_cleanup(app->channels);
+	app->channels = NULL;
+}
+
+struct app *app_create(const char *name, stasis_app_cb handler, void *data)
+{
+	RAII_VAR(struct app *, app, NULL, ao2_cleanup);
+	size_t size;
+
+	ast_assert(name != NULL);
+	ast_assert(handler != NULL);
+
+	size = sizeof(*app) + strlen(name) + 1;
+	app = ao2_alloc_options(size, app_dtor, AO2_ALLOC_OPT_LOCK_MUTEX);
+
+	if (!app) {
+		return NULL;
+	}
+
+	strncpy(app->name, name, size - sizeof(*app));
+	app->handler = handler;
+	ao2_ref(data, +1);
+	app->data = data;
+
+	app->channels = ast_str_container_alloc(APP_CHANNELS_BUCKETS);
+	if (!app->channels) {
+		return NULL;
+	}
+
+	ao2_ref(app, +1);
+	return app;
+}
+
+int app_add_channel(struct app *app, const struct ast_channel *chan)
+{
+	const char *uniqueid;
+	ast_assert(chan != NULL);
+	ast_assert(app != NULL);
+
+	uniqueid = ast_channel_uniqueid(chan);
+	if (!ast_str_container_add(app->channels, uniqueid)) {
+		return -1;
+	}
+	return 0;
+}
+
+void app_remove_channel(struct app* app, const struct ast_channel *chan)
+{
+	ast_assert(chan != NULL);
+	ast_assert(app != NULL);
+
+	ao2_find(app->channels, ast_channel_uniqueid(chan), OBJ_KEY | OBJ_NODATA | OBJ_UNLINK);
+}
+
+/*!
+ * \brief Send a message to the given application.
+ * \param app App to send the message to.
+ * \param message Message to send.
+ */
+void app_send(struct app *app, struct ast_json *message)
+{
+	app->handler(app->data, app->name, message);
+}
+
+void app_update(struct app *app, stasis_app_cb handler, void *data)
+{
+	SCOPED_AO2LOCK(lock, app);
+
+	app->handler = handler;
+	ao2_cleanup(app->data);
+	ao2_ref(data, +1);
+	app->data = data;
+}
+
+const char *app_name(const struct app *app)
+{
+	return app->name;
+}
+
+int app_is_watching_channel(struct app *app, const char *uniqueid)
+{
+	RAII_VAR(char *, found, NULL, ao2_cleanup);
+	found = ao2_find(app->channels, uniqueid, OBJ_KEY);
+	return found != NULL;
+}
diff --git a/res/stasis/app.h b/res/stasis/app.h
new file mode 100644
index 000000000..7b76db107
--- /dev/null
+++ b/res/stasis/app.h
@@ -0,0 +1,77 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, Digium, Inc.
+ *
+ * David M. Lee, II <dlee@digium.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.
+ */
+
+#ifndef _ASTERISK_RES_STASIS_APP_H
+#define _ASTERISK_RES_STASIS_APP_H
+
+/*! \file
+ *
+ * \brief Internal API for the Stasis application controller.
+ *
+ * \author David M. Lee, II <dlee@digium.com>
+ * \since 12
+ */
+
+#include "asterisk/channel.h"
+#include "asterisk/stasis.h"
+#include "asterisk/stasis_app.h"
+
+/*!
+ * \brief Opaque pointer to \c res_stasis app structure.
+ */
+struct app;
+
+/*!
+ * \brief Create a res_stasis application.
+ *
+ * \param name Name of the application.
+ * \param handler Callback for messages sent to the application.
+ * \param data Data pointer provided to the callback.
+ * \return New \c res_stasis application.
+ * \return \c NULL on error.
+ */
+struct app *app_create(const char *name, stasis_app_cb handler, void *data);
+
+/*!
+ * \brief Update the handler and data for a \c res_stasis application.
+ *
+ * \param app Application to update.
+ * \param handler New application callback.
+ * \param data New data pointer for the callback.
+ */
+void app_update(struct app *app, stasis_app_cb handler, void *data);
+
+const char *app_name(const struct app *app);
+
+struct stasis_subscription *app_subscribe(struct app *app,
+	struct stasis_topic *topic);
+
+void app_send(struct app *app, struct ast_json *message);
+
+int app_send_start_msg(struct app *app, struct ast_channel *chan, int argc,
+	char *argv[]);
+
+int app_send_end_msg(struct app *app, struct ast_channel *chan);
+
+int app_is_watching_channel(struct app *app, const char *uniqueid);
+
+int app_add_channel(struct app* app, const struct ast_channel *chan);
+
+void app_remove_channel(struct app *app, const struct ast_channel *chan);
+
+#endif /* _ASTERISK_RES_STASIS_APP_H */
diff --git a/res/stasis/command.c b/res/stasis/command.c
new file mode 100644
index 000000000..f1f7f8f3b
--- /dev/null
+++ b/res/stasis/command.c
@@ -0,0 +1,95 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, Digium, Inc.
+ *
+ * David M. Lee, II <dlee@digium.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 Stasis application command support.
+ *
+ * \author David M. Lee, II <dlee@digium.com>
+ */
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "command.h"
+
+#include "asterisk/lock.h"
+#include "asterisk/stasis_app_impl.h"
+
+struct stasis_app_command {
+	ast_mutex_t lock;
+	ast_cond_t condition;
+	stasis_app_command_cb callback;
+	void *data;
+	void *retval;
+	int is_done:1;
+};
+
+static void command_dtor(void *obj)
+{
+	struct stasis_app_command *command = obj;
+	ast_mutex_destroy(&command->lock);
+	ast_cond_destroy(&command->condition);
+}
+
+struct stasis_app_command *command_create(
+	stasis_app_command_cb callback, void *data)
+{
+	RAII_VAR(struct stasis_app_command *, command, NULL, ao2_cleanup);
+
+	command = ao2_alloc(sizeof(*command), command_dtor);
+	if (!command) {
+		return NULL;
+	}
+
+	ast_mutex_init(&command->lock);
+	ast_cond_init(&command->condition, 0);
+	command->callback = callback;
+	command->data = data;
+
+	ao2_ref(command, +1);
+	return command;
+}
+
+static void command_complete(struct stasis_app_command *command, void *retval)
+{
+	SCOPED_MUTEX(lock, &command->lock);
+
+	command->is_done = 1;
+	command->retval = retval;
+	ast_cond_signal(&command->condition);
+}
+
+void *command_join(struct stasis_app_command *command)
+{
+	SCOPED_MUTEX(lock, &command->lock);
+	while (!command->is_done) {
+		ast_cond_wait(&command->condition, &command->lock);
+	}
+
+	return command->retval;
+}
+
+void command_invoke(struct stasis_app_command *command,
+	struct stasis_app_control *control, struct ast_channel *chan)
+{
+	void *retval = command->callback(control, chan, command->data);
+	command_complete(command, retval);
+}
+
diff --git a/res/stasis/command.h b/res/stasis/command.h
new file mode 100644
index 000000000..21f4df0c0
--- /dev/null
+++ b/res/stasis/command.h
@@ -0,0 +1,42 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, Digium, Inc.
+ *
+ * David M. Lee, II <dlee@digium.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.
+ */
+
+#ifndef _ASTERISK_RES_STASIS_COMMAND_H
+#define _ASTERISK_RES_STASIS_COMMAND_H
+
+/*! \file
+ *
+ * \brief Internal API for the Stasis application commands.
+ *
+ * \author David M. Lee, II <dlee@digium.com>
+ * \since 12
+ */
+
+#include "asterisk/stasis_app_impl.h"
+
+struct stasis_app_command;
+
+struct stasis_app_command *command_create(
+	stasis_app_command_cb callback, void *data);
+
+void command_invoke(struct stasis_app_command *command,
+	struct stasis_app_control *control, struct ast_channel *chan);
+
+void *command_join(struct stasis_app_command *command);
+
+#endif /* _ASTERISK_RES_STASIS_CONTROL_H */
diff --git a/res/stasis/control.c b/res/stasis/control.c
new file mode 100644
index 000000000..e32781b5f
--- /dev/null
+++ b/res/stasis/control.c
@@ -0,0 +1,199 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, Digium, Inc.
+ *
+ * David M. Lee, II <dlee@digium.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 Stasis application control support.
+ *
+ * \author David M. Lee, II <dlee@digium.com>
+ */
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "asterisk/stasis_channels.h"
+
+#include "command.h"
+#include "control.h"
+
+struct stasis_app_control {
+	/*! Queue of commands to dispatch on the channel */
+	struct ao2_container *command_queue;
+	/*!
+	 * When set, /c app_stasis should exit and continue in the dialplan.
+	 */
+	int is_done:1;
+	/*!
+	 * The associated channel.
+	 * Be very careful with the threading associated w/ manipulating
+	 * the channel.
+	 */
+	struct ast_channel *channel;
+};
+
+struct stasis_app_control *control_create(struct ast_channel *channel)
+{
+	struct stasis_app_control *control;
+
+	control = ao2_alloc(sizeof(*control), NULL);
+	if (!control) {
+		return NULL;
+	}
+
+	control->command_queue = ao2_container_alloc_list(0, 0, NULL, NULL);
+
+	control->channel = channel;
+
+	return control;
+}
+
+static struct stasis_app_command *exec_command(
+	struct stasis_app_control *control, stasis_app_command_cb command_fn,
+	void *data)
+{
+	RAII_VAR(struct stasis_app_command *, command, NULL, ao2_cleanup);
+
+	command = command_create(command_fn, data);
+
+	if (!command) {
+		return NULL;
+	}
+
+	ao2_lock(control);
+	ao2_ref(command, +1);
+	ao2_link(control->command_queue, command);
+	ao2_unlock(control);
+
+	ao2_ref(command, +1);
+	return command;
+}
+
+int control_is_done(struct stasis_app_control *control)
+{
+	/* Called from stasis_app_exec thread; no lock needed */
+	return control->is_done;
+}
+
+static void *app_control_continue(struct stasis_app_control *control,
+	struct ast_channel *chan, void *data)
+{
+	/* Called from stasis_app_exec thread; no lock needed */
+	control->is_done = 1;
+	return NULL;
+}
+
+void stasis_app_control_continue(struct stasis_app_control *control)
+{
+	stasis_app_send_command_async(control, app_control_continue, NULL);
+}
+
+struct ast_channel_snapshot *stasis_app_control_get_snapshot(
+	const struct stasis_app_control *control)
+{
+	RAII_VAR(struct stasis_message *, msg, NULL, ao2_cleanup);
+	struct stasis_caching_topic *caching_topic;
+	struct ast_channel_snapshot *snapshot;
+
+	caching_topic = ast_channel_topic_all_cached();
+	ast_assert(caching_topic != NULL);
+
+	msg = stasis_cache_get(caching_topic, ast_channel_snapshot_type(),
+		stasis_app_control_get_channel_id(control));
+	if (!msg) {
+		return NULL;
+	}
+
+	snapshot = stasis_message_data(msg);
+	ast_assert(snapshot != NULL);
+
+	ao2_ref(snapshot, +1);
+	return snapshot;
+}
+
+void *stasis_app_send_command(struct stasis_app_control *control,
+	stasis_app_command_cb command_fn, void *data)
+{
+	RAII_VAR(struct stasis_app_command *, command, NULL, ao2_cleanup);
+
+	if (control == NULL) {
+		return NULL;
+	}
+
+	command = exec_command(control, command_fn, data);
+	if (!command) {
+		return NULL;
+	}
+
+	return command_join(command);
+}
+
+int stasis_app_send_command_async(struct stasis_app_control *control,
+	stasis_app_command_cb command_fn, void *data)
+{
+	RAII_VAR(struct stasis_app_command *, command, NULL, ao2_cleanup);
+
+	if (control == NULL) {
+		return -1;
+	}
+
+	command = exec_command(control, command_fn, data);
+	if (!command) {
+		return -1;
+	}
+
+	return 0;
+}
+
+const char *stasis_app_control_get_channel_id(
+	const struct stasis_app_control *control)
+{
+	return ast_channel_uniqueid(control->channel);
+}
+
+void stasis_app_control_publish(
+	struct stasis_app_control *control, struct stasis_message *message)
+{
+	if (!control || !control->channel || !message) {
+		return;
+	}
+	stasis_publish(ast_channel_topic(control->channel), message);
+}
+
+int control_dispatch_all(struct stasis_app_control *control,
+	struct ast_channel *chan)
+{
+	int count = 0;
+	struct ao2_iterator i;
+	void *obj;
+
+	SCOPED_AO2LOCK(lock, control);
+
+	ast_assert(control->channel == chan);
+
+	i = ao2_iterator_init(control->command_queue, AO2_ITERATOR_UNLINK);
+
+	while ((obj = ao2_iterator_next(&i))) {
+		RAII_VAR(struct stasis_app_command *, command, obj, ao2_cleanup);
+		command_invoke(command, control, chan);
+		++count;
+	}
+
+	ao2_iterator_destroy(&i);
+	return count;
+}
diff --git a/res/stasis/control.h b/res/stasis/control.h
new file mode 100644
index 000000000..9a4243be1
--- /dev/null
+++ b/res/stasis/control.h
@@ -0,0 +1,55 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2013, Digium, Inc.
+ *
+ * David M. Lee, II <dlee@digium.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.
+ */
+
+#ifndef _ASTERISK_RES_STASIS_CONTROL_H
+#define _ASTERISK_RES_STASIS_CONTROL_H
+
+/*! \file
+ *
+ * \brief Internal API for the Stasis application controller.
+ *
+ * \author David M. Lee, II <dlee@digium.com>
+ * \since 12
+ */
+
+#include "asterisk/stasis_app.h"
+
+/*!
+ * \brief Create a control object.
+ *
+ * \param channel Channel to control.
+ * \return New control object.
+ * \return \c NULL on error.
+ */
+struct stasis_app_control *control_create(struct ast_channel *channel);
+
+/*!
+ * \brief Dispatch all commands enqueued to this control.
+ *
+ * \param control Control object to dispatch.
+ * \param chan Associated channel.
+ * \return Number of commands executed
+ */
+int control_dispatch_all(struct stasis_app_control *control,
+	struct ast_channel *chan);
+
+int control_is_done(struct stasis_app_control *control);
+
+void control_continue(struct stasis_app_control *control);
+
+#endif /* _ASTERISK_RES_STASIS_CONTROL_H */