libvlc: simplify logging callback

Remove static data, and keep each callback correctly scoped to its
LibVLC instance.

include/vlc_interface.h

@@ -103,23 +103,20 @@ VLC_API void libvlc_Quit( libvlc_int_t * );
 
 /**
  * Message logging callback signature.
- * Accepts one private data pointer, the message, and an overrun counter.
+ * \param data data pointer as provided to vlc_msg_SetCallback().
+ * \param type message type (VLC_MSG_* values from enum msg_item_type)
+ * \param item meta informations
+ * \param fmt format string
+ * \param args format string arguments
  */
-typedef void (*msg_callback_t) (void *, int, const msg_item_t *,
-                                const char *, va_list);
+typedef void (*vlc_log_cb) (void *data, int type, const msg_item_t *item,
+                            const char *fmt, va_list args);
 
-/**
- * Used by interface plugins which subscribe to the message bank.
- */
-typedef struct msg_subscription
-{
-    struct msg_subscription *prev, *next;
-    msg_callback_t func;
-    void *opaque;
-} msg_subscription_t;
+VLC_API void vlc_LogSet(libvlc_int_t *, vlc_log_cb cb, void *data);
 
-VLC_API void vlc_Subscribe(msg_subscription_t *, msg_callback_t, void *);
-VLC_API void vlc_Unsubscribe(msg_subscription_t *);
+typedef struct msg_subscription { } msg_subscription_t;
+#define vlc_Subscribe(sub,cb,data) ((sub), (cb), (data))
+#define vlc_Unsubscribe(sub) ((void)(sub))
 
 /*@}*/
 

modules/misc/logger.c

@@ -194,7 +194,7 @@ static int Open( vlc_object_t *p_this )
         return VLC_ENOMEM;
 
     p_sys->p_file = NULL;
-    msg_callback_t cb = TextPrint;
+    vlc_log_cb cb = TextPrint;
     const char *filename = LOG_FILE_TEXT, *header = TEXT_HEADER;
     p_sys->footer = TEXT_FOOTER;
 

src/libvlc.c

@@ -179,6 +179,8 @@ int libvlc_InternalInit( libvlc_int_t *p_libvlc, int i_argc,
         priv->i_verbose = -1;
     }
 
+    vlc_LogInit (p_libvlc);
+
     /* Announce who we are (TODO: only first instance?) */
     msg_Dbg( p_libvlc, "VLC media player - %s", VERSION_MESSAGE );
     msg_Dbg( p_libvlc, "%s", COPYRIGHT_MESSAGE );
@@ -210,6 +212,7 @@ int libvlc_InternalInit( libvlc_int_t *p_libvlc, int i_argc,
     if( config_LoadCmdLine( p_libvlc, i_argc, ppsz_argv, &vlc_optind ) )
     {
         module_EndBank (true);
+        vlc_LogDeinit (p_libvlc);
         return VLC_EGENERIC;
     }
 
@@ -233,6 +236,7 @@ int libvlc_InternalInit( libvlc_int_t *p_libvlc, int i_argc,
     {
         msg_Err( p_libvlc, "No plugins found! Check your VLC installation.");
         module_EndBank (true);
+        vlc_LogDeinit (p_libvlc);
         return VLC_ENOMOD;
     }
 
@@ -246,6 +250,7 @@ int libvlc_InternalInit( libvlc_int_t *p_libvlc, int i_argc,
         {
             msg_Err( p_libvlc, "Unable to fork vlc to daemon mode" );
             module_EndBank (true);
+            vlc_LogDeinit (p_libvlc);
             return VLC_ENOMEM;
         }
         b_daemon = true;
@@ -622,7 +627,7 @@ void libvlc_InternalCleanup( libvlc_int_t *p_libvlc )
 
     /* Free module bank. It is refcounted, so we call this each time  */
     module_EndBank (true);
-
+    vlc_LogDeinit (p_libvlc);
 #if defined(WIN32) || defined(__OS2__)
     system_End( );
 #endif

src/libvlc.h

@@ -74,6 +74,12 @@ void vlc_assert_locked (vlc_mutex_t *);
 # define vlc_assert_locked( m ) (void)m
 #endif
 
+/*
+ * Logging
+ */
+void vlc_LogInit(libvlc_int_t *);
+void vlc_LogDeinit(libvlc_int_t *);
+
 /*
  * LibVLC exit event handling
  */
@@ -141,7 +147,13 @@ typedef struct libvlc_priv_t
 {
     libvlc_int_t       public_data;
 
-    /* Messages */
+    /* Logging */
+    struct
+    {
+        void (*cb) (void *, int, const msg_item_t *, const char *, va_list);
+        void *opaque;
+        vlc_rwlock_t lock;
+    } log;
     signed char        i_verbose;   ///< info messages
     bool               b_color;     ///< color messages?
     bool               b_stats;     ///< Whether to collect stats

src/libvlccore.sym

@@ -255,9 +255,8 @@ module_unneed
 vlc_module_load
 vlc_module_unload
 vlc_Log
+vlc_LogSet
 vlc_vaLog
-vlc_Subscribe
-vlc_Unsubscribe
 msleep
 mstrtime
 mwait

src/misc/messages.c

@@ -49,51 +49,6 @@
 #include <vlc_charset.h>
 #include "../libvlc.h"
 
-/**
- * Store all data required by messages interfaces.
- */
-vlc_rwlock_t msg_lock = VLC_STATIC_RWLOCK;
-msg_subscription_t *msg_head;
-
-/**
- * Subscribe to the message queue.
- * Whenever a message is emitted, a callback will be called.
- * Callback invocation are serialized within a subscription.
- *
- * @param cb callback function
- * @param opaque data for the callback function
- */
-void vlc_Subscribe (msg_subscription_t *sub, msg_callback_t cb, void *opaque)
-{
-    sub->prev = NULL;
-    sub->func = cb;
-    sub->opaque = opaque;
-
-    vlc_rwlock_wrlock (&msg_lock);
-    sub->next = msg_head;
-    msg_head = sub;
-    vlc_rwlock_unlock (&msg_lock);
-}
-
-/**
- * Unsubscribe from the message queue.
- * This function waits for the message callback to return if needed.
- */
-void vlc_Unsubscribe (msg_subscription_t *sub)
-{
-    vlc_rwlock_wrlock (&msg_lock);
-    if (sub->next != NULL)
-        sub->next->prev = sub->prev;
-    if (sub->prev != NULL)
-        sub->prev->next = sub->next;
-    else
-    {
-        assert (msg_head == sub);
-        msg_head = sub->next;
-    }
-    vlc_rwlock_unlock (&msg_lock);
-}
-
 /**
  * Emit a log message.
  * \param obj VLC object emitting the message or NULL
@@ -112,9 +67,6 @@ void vlc_Log (vlc_object_t *obj, int type, const char *module,
     va_end (args);
 }
 
-static void PrintColorMsg (void *, int, const msg_item_t *,
-                           const char *, va_list);
-static void PrintMsg (void *, int, const msg_item_t *, const char *, va_list);
 #ifdef WIN32
 static void Win32DebugOutputMsg (void *, int , const msg_item_t *,
                                  const char *, va_list);
@@ -205,32 +157,20 @@ void vlc_vaLog (vlc_object_t *obj, int type, const char *module,
             break;
         }
 
-    /* Pass message to subscribers */
+    /* Pass message to the callback */
     libvlc_priv_t *priv = libvlc_priv (obj->p_libvlc);
 
+#ifdef WIN32
     va_list ap;
 
-    va_copy (ap, args);
-    if (priv->b_color)
-        PrintColorMsg (&priv->i_verbose, type, &msg, format, ap);
-    else
-        PrintMsg (&priv->i_verbose, type, &msg, format, ap);
-    va_end (ap);
-
-#ifdef WIN32
     va_copy (ap, args);
     Win32DebugOutputMsg (&priv->i_verbose, type, &msg, format, ap);
     va_end (ap);
 #endif
 
-    vlc_rwlock_rdlock (&msg_lock);
-    for (msg_subscription_t *sub = msg_head; sub != NULL; sub = sub->next)
-    {
-        va_copy (ap, args);
-        sub->func (sub->opaque, type, &msg, format, ap);
-        va_end (ap);
-    }
-    vlc_rwlock_unlock (&msg_lock);
+    vlc_rwlock_rdlock (&priv->log.lock);
+    priv->log.cb (priv->log.opaque, type, &msg, format, args);
+    vlc_rwlock_unlock (&priv->log.lock);
 
     uselocale (locale);
     freelocale (c);
@@ -248,10 +188,10 @@ static const char msg_color[4][8] = { WHITE, RED, YELLOW, GRAY };
 static void PrintColorMsg (void *d, int type, const msg_item_t *p_item,
                            const char *format, va_list ap)
 {
-    const signed char *pverbose = d;
     FILE *stream = stderr;
+    int verbose = (intptr_t)d;
 
-    if (*pverbose < 0 || *pverbose < (type - VLC_MSG_ERR))
+    if (verbose < 0 || verbose < (type - VLC_MSG_ERR))
         return;
 
     int canc = vlc_savecancel ();
@@ -274,10 +214,10 @@ static void PrintColorMsg (void *d, int type, const msg_item_t *p_item,
 static void PrintMsg (void *d, int type, const msg_item_t *p_item,
                       const char *format, va_list ap)
 {
-    const signed char *pverbose = d;
     FILE *stream = stderr;
+    int verbose = (intptr_t)d;
 
-    if (*pverbose < 0 || *pverbose < (type - VLC_MSG_ERR))
+    if (verbose < 0 || verbose < (type - VLC_MSG_ERR))
         return;
 
     int canc = vlc_savecancel ();
@@ -337,3 +277,39 @@ static void Win32DebugOutputMsg (void* d, int type, const msg_item_t *p_item,
     free(msg);
 }
 #endif
+
+/**
+ * Sets the message logging callback.
+ * \param cb message callback, or NULL to reset
+ * \param data data pointer for the message callback
+ */
+void vlc_LogSet (libvlc_int_t *vlc, vlc_log_cb cb, void *opaque)
+{
+    libvlc_priv_t *priv = libvlc_priv (vlc);
+
+    if (cb == NULL)
+    {
+        cb = priv->b_color ? PrintColorMsg : PrintMsg;
+        opaque = (void *)(intptr_t)priv->i_verbose;
+    }
+
+    vlc_rwlock_wrlock (&priv->log.lock);
+    priv->log.cb = cb;
+    priv->log.opaque = opaque;
+    vlc_rwlock_unlock (&priv->log.lock);
+}
+
+void vlc_LogInit (libvlc_int_t *vlc)
+{
+    libvlc_priv_t *priv = libvlc_priv (vlc);
+
+    vlc_rwlock_init (&priv->log.lock);
+    vlc_LogSet (vlc, NULL, NULL);
+}
+
+void vlc_LogDeinit (libvlc_int_t *vlc)
+{
+    libvlc_priv_t *priv = libvlc_priv (vlc);
+
+    vlc_rwlock_destroy (&priv->log.lock);
+}

src/os2/thread.c

@@ -128,7 +128,7 @@ static ULONG vlc_Sleep (ULONG ulTimeout)
 
 static vlc_mutex_t super_mutex;
 static vlc_cond_t  super_variable;
-extern vlc_rwlock_t config_lock, msg_lock;
+extern vlc_rwlock_t config_lock;
 
 int _CRT_init(void);
 void _CRT_term(void);
@@ -149,13 +149,11 @@ unsigned long _System _DLL_InitTerm(unsigned long hmod, unsigned long flag)
             vlc_cond_init (&super_variable);
             vlc_threadvar_create (&thread_key, NULL);
             vlc_rwlock_init (&config_lock);
-            vlc_rwlock_init (&msg_lock);
             vlc_CPU_init ();
 
             return 1;
 
         case 1 :    /* Termination */
-            vlc_rwlock_destroy (&msg_lock);
             vlc_rwlock_destroy (&config_lock);
             vlc_threadvar_delete (&thread_key);
             vlc_cond_destroy (&super_variable);

src/win32/thread.c

@@ -923,7 +923,7 @@ void vlc_threads_setup (libvlc_int_t *p_libvlc)
     SelectClockSource (VLC_OBJECT(p_libvlc));
 }
 
-extern vlc_rwlock_t config_lock, msg_lock;
+extern vlc_rwlock_t config_lock;
 BOOL WINAPI DllMain (HINSTANCE, DWORD, LPVOID);
 
 BOOL WINAPI DllMain (HINSTANCE hinstDll, DWORD fdwReason, LPVOID lpvReserved)
@@ -939,12 +939,10 @@ BOOL WINAPI DllMain (HINSTANCE hinstDll, DWORD fdwReason, LPVOID lpvReserved)
             vlc_cond_init (&super_variable);
             vlc_threadvar_create (&thread_key, NULL);
             vlc_rwlock_init (&config_lock);
-            vlc_rwlock_init (&msg_lock);
             vlc_CPU_init ();
             break;
 
         case DLL_PROCESS_DETACH:
-            vlc_rwlock_destroy (&msg_lock);
             vlc_rwlock_destroy (&config_lock);
             vlc_threadvar_delete (&thread_key);
             vlc_cond_destroy (&super_variable);