Some scheduler API cleanup and improvements.

Previously, I had added the ast_sched_thread stuff that was a generic scheduler
thread implementation.  However, if you used it, it required using different
functions for modifying scheduler contents.  This patch reworks how this is
done and just allows you to optionally start a thread on the original scheduler
context structure that has always been there.  This makes it trivial to switch
to the generic scheduler thread implementation without having to touch any of
the other code that adds or removes scheduler entries.

In passing, I made some naming tweaks to add ast_ prefixes where they were not
there before.

Review: https://reviewboard.asterisk.org/r/1007/


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@299091 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 74 insertions, 148 deletions

diff --git a/include/asterisk/sched.h b/include/asterisk/sched.h
index 4f5fb4217..c5581fb09 100644
--- a/include/asterisk/sched.h
+++ b/include/asterisk/sched.h
@@ -1,9 +1,10 @@
 /*
  * Asterisk -- An open source telephony toolkit.
  *
- * Copyright (C) 1999 - 2005, Digium, Inc.
+ * Copyright (C) 1999 - 2010, Digium, Inc.
  *
  * Mark Spencer <markster@digium.com>
+ * Russell Bryant <russell@digium.com>
  *
  * See http://www.asterisk.org for more information about
  * the Asterisk project. Please do not directly contact
@@ -27,16 +28,10 @@
 extern "C" {
 #endif
 
-
-/*! \brief Max num of schedule structs
- * \note The max number of schedule structs to keep around
- * for use.  Undefine to disable schedule structure
- * caching. (Only disable this on very low memory
- * machines)
- */
-#define SCHED_MAX_CACHE 128
-
-/*! \brief a loop construct to ensure that
+/*! 
+ * \brief Remove a scheduler entry
+ *
+ * This is a loop construct to ensure that
  * the scheduled task get deleted. The idea is that
  * if we loop attempting to remove the scheduled task,
  * then whatever callback had been running will complete
@@ -137,25 +132,27 @@ extern "C" {
 #define AST_SCHED_REPLACE_UNREF(id, sched, when, callback, data, unrefcall, addfailcall, refcall) \
 	AST_SCHED_REPLACE_VARIABLE_UNREF(id, sched, when, callback, data, 0, unrefcall, addfailcall, refcall)
 
-struct sched_context;
-
-/*! \brief New schedule context
- * \note Create a scheduling context
+/*!
+ * \brief Create a scheduler context
+ *
  * \return Returns a malloc'd sched_context structure, NULL on failure
  */
-struct sched_context *sched_context_create(void);
+struct ast_sched_context *ast_sched_context_create(void);
 
-/*! \brief destroys a schedule context
- * Destroys (free's) the given sched_context structure
+/*!
+ * \brief destroys a schedule context
+ *
  * \param c Context to free
- * \return Returns 0 on success, -1 on failure
  */
-void sched_context_destroy(struct sched_context *c);
+void ast_sched_context_destroy(struct ast_sched_context *c);
 
-/*! \brief callback for a cheops scheduler
- * A cheops scheduler callback takes a pointer with callback data and
- * \return returns a 0 if it should not be run again, or non-zero if it should be
- * rescheduled to run again
+/*!
+ * \brief scheduler callback
+ *
+ * A scheduler callback takes a pointer with callback data and
+ *
+ * \retval 0 if the callback should not be rescheduled
+ * \retval non-zero if the callback should be scheduled agai
  */
 typedef int (*ast_sched_cb)(const void *data);
 #define AST_SCHED_CB(a) ((ast_sched_cb)(a))
@@ -173,20 +170,25 @@ struct ast_cb_names {
  * \param cbnames to check against
  * \since 1.6.1
  */
-void ast_sched_report(struct sched_context *con, struct ast_str **buf, struct ast_cb_names *cbnames);
-		
-/*! \brief Adds a scheduled event
+void ast_sched_report(struct ast_sched_context *con, struct ast_str **buf, struct ast_cb_names *cbnames);
+
+/*!
+ * \brief Adds a scheduled event
+ *
  * Schedule an event to take place at some point in the future.  callback
  * will be called with data as the argument, when milliseconds into the
  * future (approximately)
+ *
  * If callback returns 0, no further events will be re-scheduled
+ *
  * \param con Scheduler context to add
  * \param when how many milliseconds to wait for event to occur
  * \param callback function to call when the amount of time expires
  * \param data data to pass to the callback
+ *
  * \return Returns a schedule item ID on success, -1 on failure
  */
-int ast_sched_add(struct sched_context *con, int when, ast_sched_cb callback, const void *data) attribute_warn_unused_result;
+int ast_sched_add(struct ast_sched_context *con, int when, ast_sched_cb callback, const void *data) attribute_warn_unused_result;
 
 /*!
  * \brief replace a scheduler entry
@@ -199,22 +201,27 @@ int ast_sched_add(struct sched_context *con, int when, ast_sched_cb callback, co
  * \retval -1 failure
  * \retval otherwise, returns scheduled item ID
  */
-int ast_sched_replace(int old_id, struct sched_context *con, int when, ast_sched_cb callback, const void *data) attribute_warn_unused_result;
+int ast_sched_replace(int old_id, struct ast_sched_context *con, int when, ast_sched_cb callback, const void *data) attribute_warn_unused_result;
 
-/*!Adds a scheduled event with rescheduling support
+/*!
+ * \brief Adds a scheduled event with rescheduling support
+ *
  * \param con Scheduler context to add
  * \param when how many milliseconds to wait for event to occur
  * \param callback function to call when the amount of time expires
  * \param data data to pass to the callback
  * \param variable If true, the result value of callback function will be
  *       used for rescheduling
+ *
  * Schedule an event to take place at some point in the future.  Callback
  * will be called with data as the argument, when milliseconds into the
  * future (approximately)
+ *
  * If callback returns 0, no further events will be re-scheduled
+ *
  * \return Returns a schedule item ID on success, -1 on failure
  */
-int ast_sched_add_variable(struct sched_context *con, int when, ast_sched_cb callback, const void *data, int variable) attribute_warn_unused_result;
+int ast_sched_add_variable(struct ast_sched_context *con, int when, ast_sched_cb callback, const void *data, int variable) attribute_warn_unused_result;
 
 /*!
  * \brief replace a scheduler entry
@@ -227,66 +234,83 @@ int ast_sched_add_variable(struct sched_context *con, int when, ast_sched_cb cal
  * \retval -1 failure
  * \retval otherwise, returns scheduled item ID
  */
-int ast_sched_replace_variable(int old_id, struct sched_context *con, int when, ast_sched_cb callback, const void *data, int variable) attribute_warn_unused_result;
+int ast_sched_replace_variable(int old_id, struct ast_sched_context *con, int when, ast_sched_cb callback, const void *data, int variable) attribute_warn_unused_result;
 
-	
 /*! 
  * \brief Find a sched structure and return the data field associated with it. 
+ *
  * \param con scheduling context in which to search fro the matching id
  * \param id ID of the scheduled item to find
  * \return the data field from the matching sched struct if found; else return NULL if not found.
+ *
  * \since 1.6.1
  */
+const void *ast_sched_find_data(struct ast_sched_context *con, int id);
 
-const void *ast_sched_find_data(struct sched_context *con, int id);
-	
-/*! \brief Deletes a scheduled event
+/*!
+ * \brief Deletes a scheduled event
+ *
  * Remove this event from being run.  A procedure should not remove its own
  * event, but return 0 instead.  In most cases, you should not call this
  * routine directly, but use the AST_SCHED_DEL() macro instead (especially if
  * you don't intend to do something different when it returns failure).
+ *
  * \param con scheduling context to delete item from
  * \param id ID of the scheduled item to delete
+ *
  * \return Returns 0 on success, -1 on failure
  */
 #ifndef AST_DEVMODE
-int ast_sched_del(struct sched_context *con, int id) attribute_warn_unused_result;
+int ast_sched_del(struct ast_sched_context *con, int id) attribute_warn_unused_result;
 #else
-int _ast_sched_del(struct sched_context *con, int id, const char *file, int line, const char *function) attribute_warn_unused_result;
+int _ast_sched_del(struct ast_sched_context *con, int id, const char *file, int line, const char *function) attribute_warn_unused_result;
 #define	ast_sched_del(a, b)	_ast_sched_del(a, b, __FILE__, __LINE__, __PRETTY_FUNCTION__)
 #endif
 
-/*! \brief Determines number of seconds until the next outstanding event to take place
+/*!
+ * \brief Determines number of seconds until the next outstanding event to take place
+ *
  * Determine the number of seconds until the next outstanding event
  * should take place, and return the number of milliseconds until
  * it needs to be run.  This value is perfect for passing to the poll
  * call.
+ *
  * \param con context to act upon
+ *
  * \return Returns "-1" if there is nothing there are no scheduled events
  * (and thus the poll should not timeout)
  */
-int ast_sched_wait(struct sched_context *con) attribute_warn_unused_result;
+int ast_sched_wait(struct ast_sched_context *con) attribute_warn_unused_result;
 
-/*! \brief Runs the queue
- * \param con Scheduling context to run
+/*!
+ * \brief Runs the queue
+ *
  * Run the queue, executing all callbacks which need to be performed
  * at this time.
+ *
+ * \param con Scheduling context to run
  * \param con context to act upon
+ *
  * \return Returns the number of events processed.
  */
-int ast_sched_runq(struct sched_context *con);
+int ast_sched_runq(struct ast_sched_context *con);
 
-/*! \brief Dumps the scheduler contents
+/*!
+ * \brief Dumps the scheduler contents
+ *
  * Debugging: Dump the contents of the scheduler to stderr
+ *
  * \param con Context to dump
  */
-void ast_sched_dump(struct sched_context *con);
+void ast_sched_dump(struct ast_sched_context *con);
 
-/*! \brief Returns the number of seconds before an event takes place
+/*!
+ * \brief Returns the number of seconds before an event takes place
+ *
  * \param con Context to use
  * \param id Id to dump
  */
-long ast_sched_when(struct sched_context *con,int id);
+long ast_sched_when(struct ast_sched_context *con,int id);
 
 /*!
  * \brief Convenience macro for objects and reference (add)
@@ -307,112 +331,14 @@ long ast_sched_when(struct sched_context *con,int id);
 } while(0)
 
 /*!
- * \brief An opaque type representing a scheduler thread
- *
- * The purpose of the ast_sched_thread API is to provide a common implementation
- * of the case where a module wants to have a dedicated thread for handling the
- * scheduler.
- */
-struct ast_sched_thread;
-
-/*!
- * \brief Create a scheduler with a dedicated thread
- *
- * This function should be used to allocate a scheduler context and a dedicated
- * thread for processing scheduler entries.  The thread is started immediately.
- *
- * \retval NULL error
- * \retval non-NULL a handle to the scheduler and its dedicated thread.
- */
-struct ast_sched_thread *ast_sched_thread_create(void);
-
-/*!
- * \brief Destroy a scheduler and its thread
- *
- * This function is used to destroy a scheduler context and the dedicated thread
- * that was created for handling scheduler entries.  Any entries in the scheduler
- * that have not yet been processed will be thrown away.  Once this function is
- * called, the handle must not be used again.
- *
- * \param st the handle to the scheduler and thread
- *
- * \return NULL for convenience
- */
-struct ast_sched_thread *ast_sched_thread_destroy(struct ast_sched_thread *st);
-
-/*!
- * \brief Add a scheduler entry
+ * \brief Start a thread for processing scheduler entries
  *
- * \param st the handle to the scheduler and thread
- * \param when the number of ms in the future to run the task.  A value <= 0
- *        is treated as "run now".
- * \param cb the function to call when the scheduled time arrives
- * \param data the parameter to pass to the scheduler callback
- *
- * \retval -1 Failure
- * \retval >=0 Sched ID of added task
- */
-int ast_sched_thread_add(struct ast_sched_thread *st, int when, ast_sched_cb cb,
-		const void *data);
-
-/*!
- * \brief Add a variable reschedule time scheduler entry
- *
- * \param st the handle to the scheduler and thread
- * \param when the number of ms in the future to run the task.  A value <= 0
- *        is treated as "run now".
- * \param cb the function to call when the scheduled time arrives
- * \param data the parameter to pass to the scheduler callback
- * \param variable If this value is non-zero, then the scheduler will use the return
- *        value of the scheduler as the amount of time in the future to run the
- *        task again.  Normally, a return value of 0 means do not re-schedule, and
- *        non-zero means re-schedule using the time provided when the scheduler
- *        entry was first created.
- *
- * \retval -1 Failure
- * \retval >=0 Sched ID of added task
- */
-int ast_sched_thread_add_variable(struct ast_sched_thread *st, int when, ast_sched_cb cb,
-		const void *data, int variable);
-
-/*!
- * \brief Get the scheduler context for a given ast_sched_thread
- *
- * This function should be used only when direct access to the scheduler context
- * is required.  Its use is discouraged unless necessary.  The cases where 
- * this is currently required is when you want to take advantage of one of the 
- * AST_SCHED macros.
- *
- * \param st the handle to the scheduler and thread
- *
- * \return the sched_context associated with an ast_sched_thread
- */
-struct sched_context *ast_sched_thread_get_context(struct ast_sched_thread *st);
-
-/*!
- * \brief Delete a scheduler entry
- *
- * This uses the AST_SCHED_DEL macro internally.
- *
- * \param st the handle to the scheduler and thread
- * \param id scheduler entry id to delete
+ * \param con the scheduler context this thread will manage
  *
  * \retval 0 success
  * \retval non-zero failure
  */
-#define ast_sched_thread_del(st, id) ({ \
-	struct sched_context *__tmp_context = ast_sched_thread_get_context(st); \
-	AST_SCHED_DEL(__tmp_context, id); \
-})
-
-/*!
- * \brief Force re-processing of the scheduler context
- *
- * \param st the handle to the scheduler and thread
- *
- * \return nothing
- */
-void ast_sched_thread_poke(struct ast_sched_thread *st);
+int ast_sched_start_thread(struct ast_sched_context *con);
 
 #if defined(__cplusplus) || defined(c_plusplus)
 }