From bf79f622861c420ae1124e031d470f2762dea24c Mon Sep 17 00:00:00 2001
From: markster <markster@f38db490-d61c-443f-a65b-d21fe96a405b>
Date: Thu, 9 Dec 2004 19:55:01 +0000
Subject: [PATCH] Make music on hold truly optional (bug #2998)

git-svn-id: http://svn.digium.com/svn/asterisk/trunk@4411 f38db490-d61c-443f-a65b-d21fe96a405b
---
 channel.c                      | 38 ++++++++++++++++++++++++++++++++++
 include/asterisk/musiconhold.h |  4 ++++
 res/res_musiconhold.c          |  5 +++--
 3 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/channel.c b/channel.c
index 39645652f..dca52974a 100755
--- a/channel.c
+++ b/channel.c
@@ -24,6 +24,7 @@
 #include <asterisk/sched.h>
 #include <asterisk/options.h>
 #include <asterisk/channel.h>
+#include <asterisk/musiconhold.h>
 #include <asterisk/channel_pvt.h>
 #include <asterisk/logger.h>
 #include <asterisk/say.h>
@@ -2959,3 +2960,40 @@ unsigned int ast_get_group(char *s)
 	}
 	return group;
 }
+
+
+static int (*ast_moh_start_ptr)(struct ast_channel *, char *) = NULL;
+static void (*ast_moh_stop_ptr)(struct ast_channel *) = NULL;
+
+
+void ast_install_music_functions(int (*start_ptr)(struct ast_channel *, char *),
+								void (*stop_ptr)(struct ast_channel *)) 
+{
+	ast_moh_start_ptr = start_ptr;
+	ast_moh_stop_ptr = stop_ptr;
+}
+
+void ast_uninstall_music_functions(void) 
+{
+	ast_moh_start_ptr = NULL;
+	ast_moh_stop_ptr = NULL;
+}
+
+/*! Turn on/off music on hold on a given channel */
+
+int ast_moh_start(struct ast_channel *chan, char *mclass) 
+{
+	if(ast_moh_start_ptr)
+		return ast_moh_start_ptr(chan, mclass);
+
+	if (option_verbose > 2)
+		ast_verbose(VERBOSE_PREFIX_3 "Music class %s requested but no musiconhold loaded.\n", mclass ? mclass : "default");
+	
+	return 0;
+}
+
+void ast_moh_stop(struct ast_channel *chan) 
+{
+	if(ast_moh_stop_ptr)
+		ast_moh_stop_ptr(chan);
+}
diff --git a/include/asterisk/musiconhold.h b/include/asterisk/musiconhold.h
index ceef76cdf..39c90bd85 100755
--- a/include/asterisk/musiconhold.h
+++ b/include/asterisk/musiconhold.h
@@ -24,6 +24,10 @@ extern int ast_moh_start(struct ast_channel *chan, char *mclass);
 /*! Turn off music on hold on a given channel */
 extern void ast_moh_stop(struct ast_channel *chan);
 
+extern void ast_install_music_functions(int (*start_ptr)(struct ast_channel *, char *),
+								 void (*stop_ptr)(struct ast_channel *));
+extern void ast_uninstall_music_functions(void);
+
 #if defined(__cplusplus) || defined(c_plusplus)
 }
 #endif
diff --git a/res/res_musiconhold.c b/res/res_musiconhold.c
index e3808da62..53d25f3da 100755
--- a/res/res_musiconhold.c
+++ b/res/res_musiconhold.c
@@ -588,7 +588,7 @@ static int moh_register(char *classname, char *mode, char *param, char *miscargs
 	return 0;
 }
 
-int ast_moh_start(struct ast_channel *chan, char *class)
+static int local_ast_moh_start(struct ast_channel *chan, char *class)
 {
 	if (!class || ast_strlen_zero(class))
 		class = chan->musicclass;
@@ -597,7 +597,7 @@ int ast_moh_start(struct ast_channel *chan, char *class)
 	return ast_activate_generator(chan, &mohgen, class);
 }
 
-void ast_moh_stop(struct ast_channel *chan)
+static void local_ast_moh_stop(struct ast_channel *chan)
 {
 	ast_deactivate_generator(chan);
 }
@@ -659,6 +659,7 @@ int load_module(void)
 {
 	int res;
 	load_moh_classes();
+	ast_install_music_functions(local_ast_moh_start, local_ast_moh_stop);
 	res = ast_register_application(app0, moh0_exec, synopsis0, descrip0);
 	ast_register_atexit(ast_moh_destroy);
 	if (!res)