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

include/asterisk/module.h

@@ -478,6 +478,9 @@ int ast_register_application2(const char *app, int (*execute)(struct ast_channel
  */
 int ast_unregister_application(const char *app);
 
+/*! Macro to safely ref and unref the self module for the current scope */
+#define SCOPED_MODULE_USE(module) \
+	RAII_VAR(struct ast_module *, __self__ ## __LINE__, ast_module_ref(module), ast_module_unref)
 
 #if defined(__cplusplus) || defined(c_plusplus)
 }

include/asterisk/stasis_app.h

@@ -53,27 +53,6 @@
 #include "asterisk/channel.h"
 #include "asterisk/json.h"
 
-struct ast_channel_snapshot;
-
-/*! @{ */
-
-/*!
- * \brief Control a channel using \c stasis_app.
- *
- * This function blocks until the channel hangs up, or
- * stasis_app_control_continue() is called on the channel's \ref
- * stasis_app_control struct.
- *
- * \param chan Channel to control with Stasis.
- * \param app_name Application controlling the channel.
- * \param argc Number of arguments for the application.
- * \param argv Arguments for the application.
- */
-int stasis_app_exec(struct ast_channel *chan, const char *app_name, int argc,
-	char *argv[]);
-
-/*! @} */
-
 /*! @{ */
 
 /*!
@@ -87,7 +66,7 @@ int stasis_app_exec(struct ast_channel *chan, const char *app_name, int argc,
  * \param message Message to handle. (borrowed copy)
  */
 typedef void (*stasis_app_cb)(void *data, const char *app_name,
-			      struct ast_json *message);
+	struct ast_json *message);
 
 /*!
  * \brief Register a new Stasis application.
@@ -147,6 +126,16 @@ 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);
 
+/*!
+ * \brief Returns the uniqueid of the channel associated with this control
+ *
+ * \param control Control object.
+ * \return Uniqueid of the associate channel.
+ * \return \c NULL if \a control is \c NULL.
+ */
+const char *stasis_app_control_get_channel_id(
+	const struct stasis_app_control *control);
+
 /*!
  * \brief Exit \c res_stasis and continue execution in the dialplan.
  *
@@ -160,20 +149,30 @@ void stasis_app_control_continue(struct stasis_app_control *control);
  * \brief Answer the channel associated with this control.
  * \param control Control for \c res_stasis.
  * \return 0 for success.
- * \return -1 for error.
+ * \return Non-zero for error.
  */
 int stasis_app_control_answer(struct stasis_app_control *control);
 
-/*! @} */
-
-/*! @{ */
+/*!
+ * \brief Returns the most recent snapshot for the associated channel.
+ *
+ * The returned pointer is AO2 managed, so ao2_cleanup() when you're done.
+ *
+ * \param control Control for \c res_stasis.
+ * \return Most recent snapshot. ao2_cleanup() when done.
+ * \return \c NULL if channel isn't in cache.
+ */
+struct ast_channel_snapshot *stasis_app_control_get_snapshot(
+	const struct stasis_app_control *control);
 
 /*!
- * \brief Build a JSON object from a \ref ast_channel_snapshot.
- * \return JSON object representing channel snapshot.
- * \return \c NULL on error
+ * \brief Publish a message to the \a control's channel's topic.
+ *
+ * \param control Control to publish to
+ * \param message Message to publish
  */
-struct ast_json *ast_channel_snapshot_to_json(const struct ast_channel_snapshot *snapshot);
+void stasis_app_control_publish(
+	struct stasis_app_control *control, struct stasis_message *message);
 
 /*!
  * \brief Increment the res_stasis reference count.

include/asterisk/stasis_app_impl.h

@@ -0,0 +1,88 @@
+/*
+ * 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_H
+#define _ASTERISK_RES_STASIS_H
+
+/*! \file
+ *
+ * \brief Backend API for implementing components of res_stasis.
+ *
+ * \author David M. Lee, II <dlee@digium.com>
+ * \since 12
+ *
+ * This file defines functions useful for defining new commands to execute
+ * on channels while they are in Stasis.
+ */
+
+#include "asterisk/stasis_app.h"
+
+/*!
+ * \since 12
+ * \brief Control a channel using \c stasis_app.
+ *
+ * This function blocks until the channel hangs up, or
+ * stasis_app_control_continue() is called on the channel's \ref
+ * stasis_app_control struct.
+ *
+ * \param chan Channel to control with Stasis.
+ * \param app_name Application controlling the channel.
+ * \param argc Number of arguments for the application.
+ * \param argv Arguments for the application.
+ */
+int stasis_app_exec(struct ast_channel *chan, const char *app_name, int argc,
+	char *argv[]);
+
+/*! Callback type for stasis app commands */
+typedef void *(*stasis_app_command_cb)(struct stasis_app_control *control,
+	struct ast_channel *chan, void *data);
+
+/*!
+ * \since 12
+ * \brief Invokes a \a command on a \a control's channel.
+ *
+ * This function dispatches the command to be executed in the context of
+ * stasis_app_exec(), so this command will block waiting for the results of
+ * the command.
+ *
+ * \param control Control object for the channel to send the command to.
+ * \param command Command function to execute.
+ * \param data Optional data to pass along with the control function.
+ * \return Return value from \a command.
+ * \return \c NULL on error.
+ */
+void *stasis_app_send_command(struct stasis_app_control *control,
+	stasis_app_command_cb command, void *data);
+
+/*!
+ * \since 12
+ * \brief Asynchronous version of stasis_app_send().
+ *
+ * This function enqueues a command for execution, but returns immediately
+ * without waiting for the response.
+ *
+ * \param control Control object for the channel to send the command to.
+ * \param command Command function to execute.
+ * \param data Optional data to pass along with the control function.
+ * \return 0 on success.
+ * \return Non-zero on error.
+ */
+int stasis_app_send_command_async(struct stasis_app_control *control,
+	stasis_app_command_cb command, void *data);
+
+#endif /* _ASTERISK_RES_STASIS_H */