Equipped libdax_msgs with reference counter. Completed its mutex protection.

cdrskin/cdrskin_timestamp.h

@@ -1 +1 @@
-#define Cdrskin_timestamP "2007.09.15.172141"
+#define Cdrskin_timestamP "2007.09.15.204320"

libburn/init.c

@@ -25,8 +25,6 @@
 #include "libdax_msgs.h"
 struct libdax_msgs *libdax_messenger= NULL;
 
-static int libdax_messenger_is_own = 1;
-
 
 int burn_running = 0;
 
@@ -309,10 +307,12 @@ void burn_allow_untested_profiles(int yes)
 /* ts A70915 : API */
 int burn_set_messenger(void *messenger)
 {
-	if (libdax_messenger_is_own)
+	struct libdax_msgs *pt;
+
+	if (libdax_msgs_refer(&pt, messenger, 0) <= 0)
+		return 0;
 	libdax_msgs_destroy(&libdax_messenger, 0);
-	libdax_messenger = (struct libdax_msgs *) messenger;
+	libdax_messenger = (struct libdax_msgs *) pt;
-	libdax_messenger_is_own = 0;
 	return 1;
 }
 

libburn/libburn.h

@@ -1877,9 +1877,8 @@ int burn_msgs_obtain(char *minimum_severity,
 
 /* ts A70915 */
 /** Replace the messenger object handle of libburn by a compatible handle
-    obtained from a related library. The own message object gets destroyed,
+    obtained from a related library. 
-    so it is IMPORTANT to shut down libburn BEFORE the library which provides
+    See also: libisofs, API function iso_get_messenger().
-    the messenger object. See also: libisofs, API function iso_get_messenger().
     @param messenger The foreign but compatible message handle.
     @return 1 : success, <=0 : failure
 */

libburn/libdax_msgs.c

@@ -138,6 +138,7 @@ int libdax_msgs_new(struct libdax_msgs **m, int flag)
  (*m)= o= (struct libdax_msgs *) malloc(sizeof(struct libdax_msgs));
  if(o==NULL)
    return(-1);
+ o->refcount= 1;
  o->oldest= NULL;
  o->youngest= NULL;
  o->count= 0;
@@ -153,43 +154,6 @@ int libdax_msgs_new(struct libdax_msgs **m, int flag)
 }
 
 
-int libdax_msgs_destroy(struct libdax_msgs **m, int flag)
-{
- struct libdax_msgs *o;
- struct libdax_msgs_item *item, *next_item;
-
- o= *m;
- if(o==NULL)
-   return(0);
-
-#ifndef LIBDAX_MSGS_SINGLE_THREADED
- if(pthread_mutex_destroy(&(o->lock_mutex))!=0) {
-   pthread_mutex_unlock(&(o->lock_mutex));
-   pthread_mutex_destroy(&(o->lock_mutex));
- }
-#endif
-
- for(item= o->oldest; item!=NULL; item= next_item) {
-   next_item= item->next;
-   libdax_msgs_item_destroy(&item,0);
- }
- free((char *) o);
- *m= NULL;
- return(1);
-}
-
-
-int libdax_msgs_set_severities(struct libdax_msgs *m, int queue_severity,
-                               int print_severity, char *print_id, int flag)
-{
- m->queue_severity= queue_severity;
- m->print_severity= print_severity;
- strncpy(m->print_id,print_id,80);
- m->print_id[80]= 0;
- return(1);
-}
-
-
 static int libdax_msgs_lock(struct libdax_msgs *m, int flag)
 {
 
@@ -220,6 +184,65 @@ static int libdax_msgs_unlock(struct libdax_msgs *m, int flag)
 }
 
 
+int libdax_msgs_destroy(struct libdax_msgs **m, int flag)
+{
+ struct libdax_msgs *o;
+ struct libdax_msgs_item *item, *next_item;
+
+ o= *m;
+ if(o==NULL)
+   return(0);
+ if(o->refcount > 1) {
+   if(libdax_msgs_lock(*m,0)<=0)
+     return(-1);
+   o->refcount--;
+   libdax_msgs_unlock(*m,0);
+   *m= NULL;
+   return(1);
+ }
+
+#ifndef LIBDAX_MSGS_SINGLE_THREADED
+ if(pthread_mutex_destroy(&(o->lock_mutex))!=0) {
+   pthread_mutex_unlock(&(o->lock_mutex));
+   pthread_mutex_destroy(&(o->lock_mutex));
+ }
+#endif
+
+ for(item= o->oldest; item!=NULL; item= next_item) {
+   next_item= item->next;
+   libdax_msgs_item_destroy(&item,0);
+ }
+ free((char *) o);
+ *m= NULL;
+ return(1);
+}
+
+
+int libdax_msgs_refer(struct libdax_msgs **pt, struct libdax_msgs *m, int flag)
+{
+ if(libdax_msgs_lock(m,0)<=0)
+   return(0);
+ m->refcount++;
+ *pt= m;
+ libdax_msgs_unlock(m,0);
+ return(1);
+}
+
+
+int libdax_msgs_set_severities(struct libdax_msgs *m, int queue_severity,
+                               int print_severity, char *print_id, int flag)
+{
+ if(libdax_msgs_lock(m,0)<=0)
+   return(0);
+ m->queue_severity= queue_severity;
+ m->print_severity= print_severity;
+ strncpy(m->print_id,print_id,80);
+ m->print_id[80]= 0;
+ libdax_msgs_unlock(m,0);
+ return(1);
+}
+
+
 int libdax_msgs__text_to_sev(char *severity_name, int *severity,
                              int flag)
 {

libburn/libdax_msgs.h

@@ -43,6 +43,8 @@ struct libdax_msgs_item {
 
 struct libdax_msgs {
 
+ int refcount;
+
  struct libdax_msgs_item *oldest;
  struct libdax_msgs_item *youngest;
  int count;
@@ -176,7 +178,8 @@ struct libdax_msgs_item;
        /* Calls initiated from inside the direct owner (e.g. from libburn) */
 
 
-/** Create new empty message handling facility with queue.
+/** Create new empty message handling facility with queue and issue a first
+    official reference to it.
     @param flag Bitfield for control purposes (unused yet, submit 0)
     @return >0 success, <=0 failure
 */
@@ -185,12 +188,28 @@ int libdax_msgs_new(struct libdax_msgs **m, int flag);
 
 /** Destroy a message handling facility and all its eventual messages.
     The submitted pointer gets set to NULL.
+    Actually only the last destroy call of all offical references to the object
+    will really dispose it. All others just decrement the reference counter.
+    Call this function only with official reference pointers obtained by
+    libdax_msgs_new() or libdax_msgs_refer(), and only once per such pointer.
     @param flag Bitfield for control purposes (unused yet, submit 0)
-    @return 1 for success, 0 for pointer to NULL
+    @return 1 for success, 0 for pointer to NULL, -1 for fatal error
 */
 int libdax_msgs_destroy(struct libdax_msgs **m, int flag);
 
 
+/** Create an official reference to an existing libdax_msgs object. The
+    references keep the object alive at least until it is released by
+    a matching number of destroy calls. So each reference MUST be revoked
+    by exactly one call to libdax_msgs_destroy().
+    @param pt The pointer to be set and registered
+    @param m  A pointer to the existing object
+    @param flag Bitfield for control purposes (unused yet, submit 0)
+    @return 1 for success, 0 for failure
+*/
+int libdax_msgs_refer(struct libdax_msgs **pt, struct libdax_msgs *o, int flag);
+
+
 /** Submit a message to a message handling facility.
     @param driveno program specific drive number. Use -1 if no number is known.
     @param error_code  Unique error code. Use only registered codes. See below.