[Mlt-devel] SF.net SVN: mlt: [1154] trunk/mlt/src/framework

[<dde...@us...>]

Revision: 1154
          http://mlt.svn.sourceforge.net/mlt/?rev=1154&view=rev
Author:   ddennedy
Date:     2008-06-29 18:53:07 -0700 (Sun, 29 Jun 2008)

Log Message:
-----------
mlt_properties.c, mlt_service.c: bugfix to make reference counting and service closure truly thread-safe. As it was, reference count increment and decrement operations were not atomic and not protected comprehensively.

Modified Paths:
--------------
    trunk/mlt/src/framework/mlt_properties.c
    trunk/mlt/src/framework/mlt_service.c

Modified: trunk/mlt/src/framework/mlt_properties.c
===================================================================
--- trunk/mlt/src/framework/mlt_properties.c	2008-06-30 01:50:06 UTC (rev 1153)
+++ trunk/mlt/src/framework/mlt_properties.c	2008-06-30 01:53:07 UTC (rev 1154)
@@ -28,7 +28,7 @@
 #include <string.h>
 #include <ctype.h>
 #include <stdarg.h>
-
+#include <pthread.h>
 #include <sys/types.h>
 #include <dirent.h>
 
@@ -46,6 +46,7 @@
 	int size;
 	mlt_properties mirror;
 	int ref_count;
+	pthread_mutex_t mutex;
 }
 property_list;
 
@@ -82,6 +83,7 @@
 
 		// Increment the ref count
 		( ( property_list * )this->local )->ref_count = 1;
+		pthread_mutex_init( &( ( property_list * )this->local )->mutex, NULL );;
 	}
 
 	// Check that initialisation was successful
@@ -186,12 +188,15 @@
 
 int mlt_properties_inc_ref( mlt_properties this )
 {
+	int result = 0;
 	if ( this != NULL )
 	{
 		property_list *list = this->local;
-		return ++ list->ref_count;
+		pthread_mutex_lock( &list->mutex );
+		result = ++ list->ref_count;
+		pthread_mutex_unlock( &list->mutex );
 	}
-	return 0;
+	return result;
 }
 
 /** Maintain ref count to allow multiple uses of an mlt object.
@@ -199,12 +204,15 @@
 
 int mlt_properties_dec_ref( mlt_properties this )
 {
+	int result = 0;
 	if ( this != NULL )
 	{
 		property_list *list = this->local;
-		return -- list->ref_count;
+		pthread_mutex_lock( &list->mutex );
+		result = -- list->ref_count;
+		pthread_mutex_unlock( &list->mutex );
 	}
-	return 0;
+	return result;
 }
 
 /** Return the ref count of this object.
@@ -903,6 +911,7 @@
 			}
 	
 			// Clear up the list
+			pthread_mutex_destroy( &list->mutex );
 			free( list->name );
 			free( list->value );
 			free( list );

Modified: trunk/mlt/src/framework/mlt_service.c
===================================================================
--- trunk/mlt/src/framework/mlt_service.c	2008-06-30 01:50:06 UTC (rev 1153)
+++ trunk/mlt/src/framework/mlt_service.c	2008-06-30 01:53:07 UTC (rev 1154)
@@ -188,11 +188,7 @@
 
 		// Increment the reference count on this producer
 		if ( producer != NULL )
-		{
-			mlt_service_lock( producer );
 			mlt_properties_inc_ref( MLT_SERVICE_PROPERTIES( producer ) );
-			mlt_service_unlock( producer );
-		}
 
 		// Now we disconnect the producer service from its consumer
 		mlt_service_disconnect( producer );
@@ -499,10 +495,8 @@
 
 void mlt_service_close( mlt_service this )
 {
-	mlt_service_lock( this );
 	if ( this != NULL && mlt_properties_dec_ref( MLT_SERVICE_PROPERTIES( this ) ) <= 0 )
 	{
-		mlt_service_unlock( this );
 		if ( this->close != NULL )
 		{
 			this->close( this->close_object );


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