+typedef struct vlc_log_early_t
+{
+ struct vlc_log_early_t *next;
+ int type;
+ vlc_log_t meta;
+ char *msg;
+} vlc_log_early_t;
+
+typedef struct
+{
+ vlc_mutex_t lock;
+ vlc_log_early_t *head;
+ vlc_log_early_t **tailp;
+} vlc_logger_early_t;
+
+static void vlc_vaLogEarly(void *d, int type, const vlc_log_t *item,
+ const char *format, va_list ap)
+{
+ vlc_logger_early_t *sys = d;
+
+ vlc_log_early_t *log = malloc(sizeof (*log));
+ if (unlikely(log == NULL))
+ return;
+
+ log->next = NULL;
+ log->type = type;
+ log->meta.i_object_id = item->i_object_id;
+ /* NOTE: Object types MUST be static constant - no need to copy them. */
+ log->meta.psz_object_type = item->psz_object_type;
+ log->meta.psz_module = item->psz_module; /* Ditto. */
+ log->meta.psz_header = item->psz_header ? strdup(item->psz_header) : NULL;
+ log->meta.file = item->file;
+ log->meta.line = item->line;
+ log->meta.func = item->func;
+
+ int canc = vlc_savecancel(); /* XXX: needed for vasprintf() ? */
+ if (vasprintf(&log->msg, format, ap) == -1)
+ log->msg = NULL;
+ vlc_restorecancel(canc);
+
+ vlc_mutex_lock(&sys->lock);
+ assert(sys->tailp != NULL);
+ assert(*(sys->tailp) == NULL);
+ *(sys->tailp) = log;
+ sys->tailp = &log->next;
+ vlc_mutex_unlock(&sys->lock);
+}
+
+static int vlc_LogEarlyOpen(vlc_logger_t *logger)
+{
+ vlc_logger_early_t *sys = malloc(sizeof (*sys));
+
+ if (unlikely(sys == NULL))
+ return -1;
+
+ vlc_mutex_init(&sys->lock);
+ sys->head = NULL;
+ sys->tailp = &sys->head;
+
+ logger->log = vlc_vaLogEarly;
+ logger->sys = sys;
+ return 0;
+}
+
+static void vlc_LogEarlyClose(vlc_logger_t *logger, void *d)
+{
+ libvlc_int_t *vlc = logger->p_libvlc;
+ vlc_logger_early_t *sys = d;
+
+ /* Drain early log messages */
+ for (vlc_log_early_t *log = sys->head, *next; log != NULL; log = next)
+ {
+ vlc_LogCallback(vlc, log->type, &log->meta, "%s",
+ (log->msg != NULL) ? log->msg : "message lost");
+ free(log->msg);
+ next = log->next;
+ free(log);
+ }
+
+ vlc_mutex_destroy(&sys->lock);
+ free(sys);
+}
+
+static void vlc_vaLogDiscard(void *d, int type, const vlc_log_t *item,
+ const char *format, va_list ap)
+{
+ (void) d; (void) type; (void) item; (void) format; (void) ap;
+}
+
+static int vlc_logger_load(void *func, va_list ap)
+{
+ vlc_log_cb (*activate)(vlc_object_t *, void **) = func;
+ vlc_logger_t *logger = va_arg(ap, vlc_logger_t *);
+ vlc_log_cb *cb = va_arg(ap, vlc_log_cb *);
+ void **sys = va_arg(ap, void **);
+
+ *cb = activate(VLC_OBJECT(logger), sys);
+ return (*cb != NULL) ? VLC_SUCCESS : VLC_EGENERIC;
+}
+
+static void vlc_logger_unload(void *func, va_list ap)
+{
+ void (*deactivate)(vlc_logger_t *) = func;
+ void *sys = va_arg(ap, void *);
+
+ deactivate(sys);
+}
+
+/**
+ * Performs preinitialization of the messages logging subsystem.
+ *
+ * Early log messages will be stored in memory until the subsystem is fully
+ * initialized with vlc_LogInit(). This enables logging before the
+ * configuration and modules bank are ready.
+ *
+ * \return 0 on success, -1 on error.
+ */
+int vlc_LogPreinit(libvlc_int_t *vlc)
+{
+ vlc_logger_t *logger = vlc_custom_create(vlc, sizeof (*logger), "logger");
+
+ libvlc_priv(vlc)->logger = logger;
+
+ if (unlikely(logger == NULL))
+ return -1;
+
+ vlc_rwlock_init(&logger->lock);
+
+ if (vlc_LogEarlyOpen(logger))
+ {
+ logger->log = vlc_vaLogDiscard;
+ return -1;
+ }
+
+ /* Announce who we are */
+ msg_Dbg(vlc, "VLC media player - %s", VERSION_MESSAGE);
+ msg_Dbg(vlc, "%s", COPYRIGHT_MESSAGE);
+ msg_Dbg(vlc, "revision %s", psz_vlc_changeset);
+ msg_Dbg(vlc, "configured with %s", CONFIGURE_LINE);
+ return 0;
+}
+
+/**
+ * Initializes the messages logging subsystem and drain the early messages to
+ * the configured log.
+ *
+ * \return 0 on success, -1 on error.
+ */
+int vlc_LogInit(libvlc_int_t *vlc)
+{
+ vlc_logger_t *logger = libvlc_priv(vlc)->logger;
+ if (unlikely(logger == NULL))
+ return -1;
+
+ vlc_log_cb cb;
+ void *sys, *early_sys = NULL;
+
+ /* TODO: module configuration item */
+ module_t *module = vlc_module_load(logger, "logger", NULL, false,
+ vlc_logger_load, logger, &cb, &sys);
+ if (module == NULL)
+ cb = vlc_vaLogDiscard;
+
+ vlc_rwlock_wrlock(&logger->lock);
+ if (logger->log == vlc_vaLogEarly)
+ early_sys = logger->sys;
+
+ logger->log = cb;
+ logger->sys = sys;
+ assert(logger->module == NULL); /* Only one call to vlc_LogInit()! */
+ logger->module = module;
+ vlc_rwlock_unlock(&logger->lock);
+
+ if (early_sys != NULL)
+ vlc_LogEarlyClose(logger, early_sys);
+
+ return 0;
+}
+