Merged revisions 287647 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.8

........
  r287647 | dvossel | 2010-09-20 17:09:16 -0500 (Mon, 20 Sep 2010) | 21 lines
  
  Addition of the FrameHook API (AKA AwesomeHooks)
  
  So far all our tools for viewing and manipulating media streams
  within Asterisk have been entirely focused on audio.  That made
  sense then, but is not scalable now.  The FrameHook API lets us
  tap into and manipulate _ANY_ type of media or signaling passed
  on a channel present today or in the future.  This tool is a step
  in the direction of expanding Asterisk's boundaries and will help
  generate some rather interesting applications in the future.
  
  In addition to the FrameHook API, a simple dialplan function
  exercising the api has been included as well.  This function
  is called FRAME_TRACE().  FRAME_TRACE() allows for the internal
  ast_frames read and written to a channel to be output.  Filters
  can be placed on this function to debug only certain types of frames.
  This function could be thought of as an internal way of doing
  ast_frame packet captures.
  
  Review: https://reviewboard.asterisk.org/r/925/
........



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@287648 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 184 insertions, 0 deletions

diff --git a/main/framehook.c b/main/framehook.c
new file mode 100644
index 000000000..2d5fd5a47
--- /dev/null
+++ b/main/framehook.c
@@ -0,0 +1,184 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2010, Digium, Inc.
+ *
+ * David Vossel <dvossel@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 FrameHooks Architecture
+ *
+ * \author David Vossel <dvossel@digium.com>
+ */
+
+#include "asterisk.h"
+
+ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
+
+#include "asterisk/channel.h"
+#include "asterisk/linkedlists.h"
+#include "asterisk/framehook.h"
+#include "asterisk/frame.h"
+
+struct ast_framehook {
+	struct ast_framehook_interface i;
+	/*! This pointer to ast_channel the framehook is attached to. */
+	struct ast_channel *chan;
+	/*! the id representing this framehook on a channel */
+	unsigned int id;
+	/*! when set, this signals the read and write function to detach the hook */
+	int detach_and_destroy_me;
+	/*! list entry for ast_framehook_list object */
+	AST_LIST_ENTRY(ast_framehook) list;
+};
+
+struct ast_framehook_list {
+	unsigned int id_count;
+	AST_LIST_HEAD_NOLOCK(, ast_framehook) list;
+};
+
+static void framehook_detach_and_destroy(struct ast_framehook *framehook)
+{
+	struct ast_frame *frame;
+	frame = framehook->i.event_cb(framehook->chan, NULL, AST_FRAMEHOOK_EVENT_DETACHED, framehook->i.data);
+	/* never assume anything about this function. If you can return a frame during
+	 * the detached event, then assume someone will. */
+	if (frame) {
+		ast_frfree(frame);
+	}
+	framehook->chan = NULL;
+
+	if (framehook->i.destroy_cb) {
+		framehook->i.destroy_cb(framehook->i.data);
+	}
+	ast_free(framehook);
+}
+
+static struct ast_frame *framehook_list_push_event(struct ast_framehook_list *framehooks, struct ast_frame *frame, enum ast_framehook_event event)
+{
+	struct ast_framehook *framehook;
+
+	if (!framehooks) {
+		return frame;
+	}
+
+	AST_LIST_TRAVERSE_SAFE_BEGIN(&framehooks->list, framehook, list) {
+		if (framehook->detach_and_destroy_me) {
+			/* this guy is signaled for destruction */
+			AST_LIST_REMOVE_CURRENT(list);
+			framehook_detach_and_destroy(framehook);
+		} else {
+			frame = framehook->i.event_cb(framehook->chan, frame, event, framehook->i.data);
+		}
+	}
+	AST_LIST_TRAVERSE_SAFE_END;
+	return frame;
+}
+
+int ast_framehook_attach(struct ast_channel *chan, struct ast_framehook_interface *i)
+{
+	struct ast_framehook *framehook;
+	struct ast_frame *frame;
+	if (i->version != AST_FRAMEHOOK_INTERFACE_VERSION) {
+		ast_log(LOG_ERROR, "Version '%hu' of framehook interface not what we compiled against (%hu)\n",
+			i->version, AST_FRAMEHOOK_INTERFACE_VERSION);
+		return -1;
+	}
+	if (!i->event_cb || !(framehook = ast_calloc(1, sizeof(*framehook)))) {
+		return -1;
+	}
+	framehook->i = *i;
+	framehook->chan = chan;
+
+	/* create the framehook list if it didn't already exist */
+	if (!chan->framehooks && !(chan->framehooks = ast_calloc(1, sizeof(*chan->framehooks)))) {
+		ast_free(framehook);
+		return -1;
+	}
+
+	framehook->id = ++chan->framehooks->id_count;
+	AST_LIST_INSERT_TAIL(&chan->framehooks->list, framehook, list);
+
+	/* Tell the event callback we're live and rocking */
+	frame = framehook->i.event_cb(framehook->chan, NULL, AST_FRAMEHOOK_EVENT_ATTACHED, framehook->i.data);
+
+	/* Never assume anything about this function. If you can return a frame during
+	 * the attached event, then assume someone will. */
+	if (frame) {
+		ast_frfree(frame);
+	}
+
+	return framehook->id;
+}
+
+int ast_framehook_detach(struct ast_channel *chan, int id)
+{
+	struct ast_framehook *framehook;
+	int res = -1;
+
+	if (!chan->framehooks) {
+		return res;
+	}
+
+	AST_LIST_TRAVERSE_SAFE_BEGIN(&chan->framehooks->list, framehook, list) {
+		if (framehook->id == id) {
+			/* we mark for detachment rather than doing explicitly here because
+			 * it needs to be safe for this function to be called within the
+			 * event callback.  If we allowed the hook to actually be destroyed
+			 * immediately here, the event callback would crash on exit. */
+			framehook->detach_and_destroy_me = 1;
+			res = 0;
+			break;
+		}
+	}
+	AST_LIST_TRAVERSE_SAFE_END;
+
+	return res;
+}
+
+int ast_framehook_list_destroy(struct ast_channel *chan)
+{
+	struct ast_framehook *framehook;
+
+	if (!chan->framehooks) {
+		return 0;
+	}
+	AST_LIST_TRAVERSE_SAFE_BEGIN(&chan->framehooks->list, framehook, list) {
+		AST_LIST_REMOVE_CURRENT(list);
+		framehook_detach_and_destroy(framehook);
+	}
+	AST_LIST_TRAVERSE_SAFE_END;
+	ast_free(chan->framehooks);
+	chan->framehooks = NULL;
+	return 0;
+}
+
+int ast_framehook_list_is_empty(struct ast_framehook_list *framehooks)
+{
+	if (!framehooks) {
+		return 1;
+	}
+	return AST_LIST_EMPTY(&framehooks->list) ? 1 : 0;
+}
+
+struct ast_frame *ast_framehook_list_write_event(struct ast_framehook_list *framehooks, struct ast_frame *frame)
+{
+	return framehook_list_push_event(framehooks, frame, AST_FRAMEHOOK_EVENT_WRITE);
+}
+
+struct ast_frame *ast_framehook_list_read_event(struct ast_framehook_list *framehooks, struct ast_frame *frame)
+{
+	return framehook_list_push_event(framehooks, frame, AST_FRAMEHOOK_EVENT_READ);
+}