add infrastructure so that timing source can be a loadable module... next steps are to convert channel.c and chan_iax2.c to use this new API, and to move all the DAHDI-specific timing source code into a new res_timing_dahdi module

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@122062 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 112 insertions, 0 deletions

diff --git a/include/asterisk/timing.h b/include/asterisk/timing.h
new file mode 100644
index 000000000..426eb8dbd
--- /dev/null
+++ b/include/asterisk/timing.h
@@ -0,0 +1,112 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2008, Digium, Inc.
+ *
+ * Kevin P. Fleming <kpfleming@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 timing.h
+  \brief Timing source management
+  \author Kevin P. Fleming <kpfleming@digium.com>
+
+  Portions of Asterisk require a timing source, a periodic trigger
+  for media handling activities. The functions in this file allow
+  a loadable module to provide a timing source for Asterisk and its
+  modules, so that those modules can request a 'timing handle' when
+  they require one. These handles are file descriptors, which can be
+  used with select() or poll().
+
+  The timing source used by Asterisk must provide the following
+  features:
+
+  1) Periodic triggers, with a configurable interval (specified in
+     millisconds).
+
+  2) Multiple outstanding triggers, each of which must be 'acked'
+     to clear it. Triggers must also be 'ackable' in quantity.
+
+  3) Continuous trigger mode, which when enabled causes every call
+     to poll() on the timer handle to immediately return.
+
+  4) Multiple 'event types', so that the code using the timer can
+     know whether the wakeup it received was due to a periodic trigger
+     or a continuous trigger.
+ */
+
+#ifndef _ASTERISK_TIMING_H
+#define _ASTERISK_TIMING_H
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+enum ast_timing_event {
+	AST_TIMING_EVENT_EXPIRED = 1,
+	AST_TIMING_EVENT_CONTINUOUS = 2,
+};
+
+struct ast_timing_functions {
+	int (*timer_open)(unsigned int rate);
+	void (*timer_close)(int handle);
+	void (*timer_ack)(int handle, unsigned int quantity);
+	int (*timer_enable_continuous)(int handle);
+	int (*timer_disable_continuous)(int handle);
+	enum ast_timing_event (*timer_get_event)(int handle);
+};
+
+/*!
+  \brief Install a set of timing functions.
+  \param funcs An instance of the \c ast_timing_functions structure with pointers
+  to the functions provided by the timing implementation.
+  \retval NULL on failure, or a handle to be passed to
+  ast_uninstall_timing_functions() on success
+ */
+void *ast_install_timing_functions(struct ast_timing_functions *funcs);
+
+/*!
+  \brief Uninstall a previously-installed set of timing functions.
+  \param handle The handle returned from a prior successful call to
+  ast_install_timing_functions().
+  \retval none
+ */
+void ast_uninstall_timing_functions(void *handle);
+
+/*!
+  \brief Open a timer handle.
+  \param rate The rate at which the timer should trigger.
+  \retval -1 on failure, or a positive integer on success
+ */
+int ast_timer_open(unsigned int rate);
+
+/*!
+  \brief Close a previously-opened timer handle.
+  \param handle The timer handle to close.
+  \retval none
+ */
+void ast_timer_close(int handle);
+
+void ast_timer_ack(int handle, unsigned int quantity);
+
+int ast_timer_enable_continuous(int handle);
+
+int ast_timer_disable_continous(int handle);
+
+enum ast_timing_event ast_timer_get_event(int handle);
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}
+#endif
+
+#endif /* _ASTERISK_TIMING_H */