Stasis application WebSocket support

This is the API that binds the Stasis dialplan application to external
Stasis applications. It also adds the beginnings of WebSocket
application support.

This module registers a dialplan function named Stasis, which is used
to put a channel into the named Stasis app. As a channel enters and
leaves the Stasis diaplan application, the Stasis app receives a
'stasis-start' and 'stasis-end' events.

Stasis apps register themselves using the stasis_app_register and
stasis_app_unregister functions. Messages are sent to an application
using stasis_app_send.

Finally, Stasis apps control channels through the use of the
stasis_app_control object, and the family of stasis_app_control_*
functions.

Other changes along for the ride are:
 * An ast_frame_dtor function that's RAII_VAR safe
 * Some common JSON encoders for name/number, timeval, and
   context/extension/priority

Review: https://reviewboard.asterisk.org/r/2361/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@384879 65c4cc65-6c06-0410-ace0-fbb531ad65f3

4 files changed, 227 insertions, 34 deletions

diff --git a/include/asterisk/app_stasis.h b/include/asterisk/app_stasis.h
new file mode 100644
index 000000000..921a35ee8
--- /dev/null
+++ b/include/asterisk/app_stasis.h
@@ -0,0 +1,138 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2012 - 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_APP_STASIS_H
+#define _ASTERISK_APP_STASIS_H
+
+/*! \file
+ *
+ * \brief Stasis Application API. See \ref app_stasis "Stasis Application API"
+ * for detailed documentation.
+ *
+ * \author David M. Lee, II <dlee@digium.com>
+ * \since 12
+ *
+ * \page app_stasis Stasis Application API
+ *
+ * This is the API that binds the Stasis dialplan application to external
+ * Stasis applications, such as \c res_stasis_websocket.
+ *
+ * This module registers a dialplan function named \c Stasis, which is used to
+ * put a channel into the named Stasis app. As a channel enters and leaves the
+ * Stasis diaplan applcation, the Stasis app receives a \c 'stasis-start' and \c
+ * 'stasis-end' events.
+ *
+ * Stasis apps register themselves using the \ref stasis_app_register and
+ * stasis_app_unregister functions. Messages are sent to an appliction using
+ * \ref stasis_app_send.
+ *
+ * Finally, Stasis apps control channels through the use of the \ref
+ * stasis_app_control object, and the family of \c stasis_app_control_*
+ * functions.
+ */
+
+#include "asterisk/channel.h"
+#include "asterisk/json.h"
+
+/*! @{ */
+
+/*!
+ * \brief Callback for Stasis application handler.
+ *
+ * The message given to the handler is a borrowed copy. If you want to keep a
+ * reference to it, you should use \c ao2_ref() to keep it around.
+ *
+ * \param data Data ptr given when registered.
+ * \param app_name Name of the application being dispatched to.
+ * \param message Message to handle. (borrowed copy)
+ */
+typedef void (*stasis_app_cb)(void *data, const char *app_name,
+			      struct ast_json *message);
+
+/*!
+ * \brief Register a new Stasis application.
+ *
+ * If an application is already registered with the given name, the old
+ * application is sent a 'replaced' message and unregistered.
+ *
+ * \param app_name Name of this application.
+ * \param handler Callback for application messages.
+ * \param data Data blob to pass to the callback. Must be AO2 managed.
+ * \return 0 for success
+ * \return -1 for error.
+ */
+int stasis_app_register(const char *app_name, stasis_app_cb handler, void *data);
+
+/*!
+ * \brief Unregister a Stasis application.
+ * \param app_name Name of the application to unregister.
+ */
+void stasis_app_unregister(const char *app_name);
+
+/*!
+ * \brief Send a message to the given Stasis application.
+ *
+ * The message given to the handler is a borrowed copy. If you want to keep a
+ * reference to it, you should use \c ao2_ref() to keep it around.
+ *
+ * \param app_name Name of the application to invoke.
+ * \param message Message to send (borrowed reference)
+ * \return 0 for success.
+ * \return -1 for error.
+ */
+int stasis_app_send(const char *app_name, struct ast_json *message);
+
+/*! @} */
+
+/*! @{ */
+
+/*! \brief Handler for controlling a channel that's in a Stasis application */
+struct stasis_app_control;
+
+/*!
+ * \brief Returns the handler for the given channel
+ * \param chan Channel to handle.
+ * \return NULL channel not in Stasis application
+ * \return Pointer to app_stasis handler.
+ */
+struct stasis_app_control *stasis_app_control_find_by_channel(
+	const struct ast_channel *chan);
+
+/*!
+ * \brief Exit \c app_stasis and continue execution in the dialplan.
+ *
+ * If the channel is no longer in \c app_stasis, this function does nothing.
+ *
+ * \param handler Handler for \c app_stasis
+ */
+void stasis_app_control_continue(struct stasis_app_control *handler);
+
+/*! @} */
+
+/*! @{ */
+
+/*!
+ * \brief Build a JSON object from a \ref ast_channel_snapshot.
+ * \return JSON object representing channel snapshot.
+ * \return \c NULL on error
+ */
+struct ast_json *ast_channel_snapshot_to_json(const struct ast_channel_snapshot *snapshot);
+
+/*! @} */
+
+#endif /* _ASTERISK_APP_STASIS_H */
diff --git a/include/asterisk/frame.h b/include/asterisk/frame.h
index 5e81b4e18..abb0c2e28 100644
--- a/include/asterisk/frame.h
+++ b/include/asterisk/frame.h
@@ -39,11 +39,11 @@ extern "C" {
 /*!
  * \page Def_Frame AST Multimedia and signalling frames
  * \section Def_AstFrame What is an ast_frame ?
- * A frame of data read used to communicate between 
+ * A frame of data read used to communicate between
  * between channels and applications.
  * Frames are divided into frame types and subclasses.
  *
- * \par Frame types 
+ * \par Frame types
  * \arg \b VOICE:  Voice data, subclass is codec (AST_FORMAT_*)
  * \arg \b VIDEO:  Video data, subclass is codec (AST_FORMAT_*)
  * \arg \b DTMF:   A DTMF digit, subclass is the digit
@@ -88,7 +88,7 @@ extern "C" {
  */
 
 /*!
- * \brief Frame types 
+ * \brief Frame types
  *
  * \note It is important that the values of each frame type are never changed,
  *       because it will break backwards compatability with older versions.
@@ -113,11 +113,11 @@ enum ast_frame_type {
 	AST_FRAME_IMAGE,
 	/*! HTML Frame */
 	AST_FRAME_HTML,
-	/*! Comfort Noise frame (subclass is level of CNG in -dBov), 
+	/*! Comfort Noise frame (subclass is level of CNG in -dBov),
 	    body may include zero or more 8-bit quantization coefficients */
 	AST_FRAME_CNG,
 	/*! Modem-over-IP data streams */
-	AST_FRAME_MODEM,	
+	AST_FRAME_MODEM,
 	/*! DTMF begin event, subclass is the digit */
 	AST_FRAME_DTMF_BEGIN,
 };
@@ -137,24 +137,24 @@ union ast_frame_subclass {
  */
 struct ast_frame {
 	/*! Kind of frame */
-	enum ast_frame_type frametype;				
+	enum ast_frame_type frametype;
 	/*! Subclass, frame dependent */
 	union ast_frame_subclass subclass;
 	/*! Length of data */
-	int datalen;				
+	int datalen;
 	/*! Number of samples in this frame */
-	int samples;				
+	int samples;
 	/*! Was the data malloc'd?  i.e. should we free it when we discard the frame? */
-	int mallocd;				
+	int mallocd;
 	/*! The number of bytes allocated for a malloc'd frame header */
 	size_t mallocd_hdr_len;
 	/*! How many bytes exist _before_ "data" that can be used if needed */
-	int offset;				
+	int offset;
 	/*! Optional source of frame for debugging */
-	const char *src;				
+	const char *src;
 	/*! Pointer to actual data */
 	union { void *ptr; uint32_t uint32; char pad[8]; } data;
-	/*! Global delivery time */		
+	/*! Global delivery time */
 	struct timeval delivery;
 	/*! For placing in a linked list */
 	AST_LIST_ENTRY(ast_frame) frame_list;
@@ -197,7 +197,7 @@ extern struct ast_frame ast_null_frame;
  * RTP header information into the space provided by AST_FRIENDLY_OFFSET instead
  * of having to create a new buffer with the necessary space allocated.
  */
-#define AST_FRIENDLY_OFFSET 	64	
+#define AST_FRIENDLY_OFFSET 	64
 #define AST_MIN_OFFSET 		32	/*! Make sure we keep at least this much handy */
 
 /*! Need the header be free'd? */
@@ -353,10 +353,10 @@ struct ast_control_pvt_cause_code {
 #define AST_OPTION_FLAG_ANSWER		5
 #define AST_OPTION_FLAG_WTF		6
 
-/*! Verify touchtones by muting audio transmission 
+/*! Verify touchtones by muting audio transmission
  * (and reception) and verify the tone is still present
  * Option data is a single signed char value 0 or 1 */
-#define AST_OPTION_TONE_VERIFY		1		
+#define AST_OPTION_TONE_VERIFY		1
 
 /*! Put a compatible channel into TDD (TTY for the hearing-impared) mode
  * Option data is a single signed char value 0 or 1 */
@@ -370,7 +370,7 @@ struct ast_control_pvt_cause_code {
  * Option data is a single signed char value 0 or 1 */
 #define	AST_OPTION_AUDIO_MODE		4
 
-/*! Set channel transmit gain 
+/*! Set channel transmit gain
  * Option data is a single signed char representing number of decibels (dB)
  * to set gain to (on top of any gain specified in channel driver) */
 #define AST_OPTION_TXGAIN		5
@@ -380,7 +380,7 @@ struct ast_control_pvt_cause_code {
  * to set gain to (on top of any gain specified in channel driver) */
 #define AST_OPTION_RXGAIN		6
 
-/* set channel into "Operator Services" mode 
+/* set channel into "Operator Services" mode
  * Option data is a struct oprmode
  *
  * \note This option should never be sent over the network */
@@ -433,7 +433,7 @@ struct ast_control_pvt_cause_code {
  * Option data is a character buffer of suitable length */
 #define AST_OPTION_DEVICE_NAME		16
 
-/*! Get the CC agent type from the channel (Read only) 
+/*! Get the CC agent type from the channel (Read only)
  * Option data is a character buffer of suitable length */
 #define AST_OPTION_CC_AGENT_TYPE    17
 
@@ -450,12 +450,12 @@ struct oprmode {
 struct ast_option_header {
 	/* Always keep in network byte order */
 #if __BYTE_ORDER == __BIG_ENDIAN
-        uint16_t flag:3;
-        uint16_t option:13;
+	uint16_t flag:3;
+	uint16_t option:13;
 #else
 #if __BYTE_ORDER == __LITTLE_ENDIAN
-        uint16_t option:13;
-        uint16_t flag:3;
+	uint16_t option:13;
+	uint16_t flag:3;
 #else
 #error Byte order not defined
 #endif
@@ -463,19 +463,19 @@ struct ast_option_header {
 		uint8_t data[0];
 };
 
-/*! \brief  Requests a frame to be allocated 
- * 
- * \param source 
- * Request a frame be allocated.  source is an optional source of the frame, 
- * len is the requested length, or "0" if the caller will supply the buffer 
+/*! \brief  Requests a frame to be allocated
+ *
+ * \param source
+ * Request a frame be allocated.  source is an optional source of the frame,
+ * len is the requested length, or "0" if the caller will supply the buffer
  */
 #if 0 /* Unimplemented */
 struct ast_frame *ast_fralloc(char *source, int len);
 #endif
 
-/*!  
+/*!
  * \brief Frees a frame or list of frames
- * 
+ *
  * \param fr Frame to free, or head of list to free
  * \param cache Whether to consider this frame for frame caching
  */
@@ -483,6 +483,12 @@ void ast_frame_free(struct ast_frame *fr, int cache);
 
 #define ast_frfree(fr) ast_frame_free(fr, 1)
 
+/*!
+ * \brief NULL-safe wrapper for \ref ast_frfree, good for \ref RAII_VAR.
+ * \param frame Frame to free, or head of list to free.
+ */
+void ast_frame_dtor(struct ast_frame *frame);
+
 /*! \brief Makes a frame independent of any static storage
  * \param fr frame to act upon
  * Take a frame, and if it's not been malloc'd, make a malloc'd copy
@@ -498,7 +504,7 @@ void ast_frame_free(struct ast_frame *fr, int cache);
  */
 struct ast_frame *ast_frisolate(struct ast_frame *fr);
 
-/*! \brief Copies a frame 
+/*! \brief Copies a frame
  * \param fr frame to copy
  * Duplicates a frame -- should only rarely be used, typically frisolate is good enough
  * \return Returns a frame on success, NULL on error
@@ -507,7 +513,7 @@ struct ast_frame *ast_frdup(const struct ast_frame *fr);
 
 void ast_swapcopy_samples(void *dst, const void *src, int samples);
 
-/* Helpers for byteswapping native samples to/from 
+/* Helpers for byteswapping native samples to/from
    little-endian and big-endian. */
 #if __BYTE_ORDER == __LITTLE_ENDIAN
 #define ast_frame_byteswap_le(fr) do { ; } while(0)
@@ -518,13 +524,13 @@ void ast_swapcopy_samples(void *dst, const void *src, int samples);
 #endif
 
 /*! \brief Parse an "allow" or "deny" line in a channel or device configuration
-        and update the capabilities and pref if provided.
+	and update the capabilities and pref if provided.
 	Video codecs are not added to codec preference lists, since we can not transcode
 	\return Returns number of errors encountered during parsing
  */
 int ast_parse_allow_disallow(struct ast_codec_pref *pref, struct ast_format_cap *cap, const char *list, int allowing);
 
-/*! \name AST_Smoother 
+/*! \name AST_Smoother
 */
 /*@{ */
 /*! \page ast_smooth The AST Frame Smoother
@@ -584,7 +590,7 @@ struct ast_frame *ast_frame_enqueue(struct ast_frame *head, struct ast_frame *f,
 
 /*! \brief Gets duration in ms of interpolation frame for a format */
 static inline int ast_codec_interp_len(struct ast_format *format)
-{ 
+{
 	return (format->id == AST_FORMAT_ILBC) ? 30 : 20;
 }
 
diff --git a/include/asterisk/json.h b/include/asterisk/json.h
index d8cf98ece..64a1e7b7a 100644
--- a/include/asterisk/json.h
+++ b/include/asterisk/json.h
@@ -764,4 +764,48 @@ struct ast_json *ast_json_deep_copy(const struct ast_json *value);
 
 /*!@}*/
 
+/*!@{*/
+
+/*!
+ * \brief Common JSON rendering functions for common 'objects'.
+ */
+
+/*!
+ * \brief Simple name/number pair.
+ * \param name Name
+ * \param number Number
+ * \return NULL if error (non-UTF8 characters, NULL inputs, etc.)
+ * \return JSON object with name and number fields
+ */
+struct ast_json *ast_json_name_number(const char *name, const char *number);
+
+/*!
+ * \brief Construct a timeval as JSON.
+ *
+ * JSON does not define a standard date format (boo), but the de facto standard
+ * is to use ISO 8601 formatted string. We build a millisecond resolution string
+ * from the \c timeval
+ *
+ * \param tv \c timeval to encode.
+ * \param zone Text string of a standard system zoneinfo file.  If NULL, the system localtime will be used.
+ * \return JSON string with ISO 8601 formatted date/time.
+ * \return \c NULL on error.
+ */
+struct ast_json *ast_json_timeval(const struct timeval *tv, const char *zone);
+
+/*!
+ * \brief Construct a context/exten/priority as JSON.
+ *
+ * If a \c NULL is passed for \c context or \c exten, or -1 for \c priority,
+ * the fields is set to ast_json_null().
+ *
+ * \param context Context name.
+ * \param exten Extension.
+ * \param priority Dialplan priority.
+ * \return JSON object with \c context, \c exten and \c priority fields
+ */
+struct ast_json *ast_json_dialplan_cep(const char *context, const char *exten, int priority);
+
+/*!@}*/
+
 #endif /* _ASTERISK_JSON_H */
diff --git a/include/asterisk/localtime.h b/include/asterisk/localtime.h
index 50f5c835c..74f342c46 100644
--- a/include/asterisk/localtime.h
+++ b/include/asterisk/localtime.h
@@ -99,4 +99,9 @@ char *ast_strptime_locale(const char *s, const char *format, struct ast_tm *tm,
 struct ast_test;
 void ast_localtime_wakeup_monitor(struct ast_test *info);
 
+/*! \brief ast_strftime for ISO8601 formatting timestamps. */
+#define AST_ISO8601_FORMAT "%FT%T.%q%z"
+/*! \brief Max length of an null terminated, millisecond resolution, ISO8601 timestamp string. */
+#define AST_ISO8601_LEN 29
+
 #endif /* _ASTERISK_LOCALTIME_H */