msg: add function to reduce log level

Sometimes it's helpful to override this for specific mp_log instances,
because in some specific circumstances you just want to suppress log
file noise you never want to see.

-1 is an allowed value (for suppressing MSGL_FATAL==0). It looks like
the libplacebo wrapper still does this wrong, so it will probably
trigger UB in some cases. I guess I don't care, though.

2 files changed, 19 insertions, 2 deletions

diff --git a/common/msg.c b/common/msg.c
index 871666add0..0d1c165222 100644
--- a/common/msg.c
+++ b/common/msg.c
@@ -86,6 +86,7 @@ struct mp_log {
     struct mp_log_root *root;
     const char *prefix;
     const char *verbose_prefix;
+    int max_level;              // minimum log level for this instance
     int level;                  // minimum log level for any outputs
     int terminal_level;         // minimum log level for terminal output
     atomic_ulong reload_counter;
@@ -125,8 +126,6 @@ static void update_loglevel(struct mp_log *log)
     struct mp_log_root *root = log->root;
     pthread_mutex_lock(&root->lock);
     log->level = MSGL_STATUS + root->verbose; // default log level
-    if (root->really_quiet)
-        log->level -= 10;
     for (int n = 0; root->msg_levels && root->msg_levels[n * 2 + 0]; n++) {
         if (match_mod(log->verbose_prefix, root->msg_levels[n * 2 + 0]))
             log->level = mp_msg_find_level(root->msg_levels[n * 2 + 1]);
@@ -143,10 +142,25 @@ static void update_loglevel(struct mp_log *log)
         log->level = MPMAX(log->level, MSGL_DEBUG);
     if (log->root->stats_file)
         log->level = MPMAX(log->level, MSGL_STATS);
+    log->level = MPMIN(log->level, log->max_level);
+    if (root->really_quiet)
+        log->level = -1;
     atomic_store(&log->reload_counter, atomic_load(&log->root->reload_counter));
     pthread_mutex_unlock(&root->lock);
 }
 
+// Set (numerically) the maximum level that should still be output for this log
+// instances. E.g. lev=MSGL_WARN => show only warnings and errors.
+void mp_msg_set_max_level(struct mp_log *log, int lev)
+{
+    if (!log->root)
+        return;
+    pthread_mutex_lock(&log->root->lock);
+    log->max_level = MPCLAMP(lev, -1, MSGL_MAX);
+    pthread_mutex_unlock(&log->root->lock);
+    update_loglevel(log);
+}
+
 // Get the current effective msg level.
 // Thread-safety: see mp_msg().
 int mp_msg_level(struct mp_log *log)
@@ -456,6 +470,7 @@ struct mp_log *mp_log_new(void *talloc_ctx, struct mp_log *parent,
     talloc_set_destructor(log, destroy_log);
     log->root = parent->root;
     log->partial = talloc_strdup(NULL, "");
+    log->max_level = MSGL_MAX;
     if (name) {
         if (name[0] == '!') {
             name = &name[1];
diff --git a/common/msg.h b/common/msg.h
index 5c580b8b84..b0cec7b88a 100644
--- a/common/msg.h
+++ b/common/msg.h
@@ -60,6 +60,8 @@ static inline bool mp_msg_test(struct mp_log *log, int lev)
     return lev <= mp_msg_level(log);
 }
 
+void mp_msg_set_max_level(struct mp_log *log, int lev);
+
 // Convenience macros.
 #define mp_fatal(log, ...)      mp_msg(log, MSGL_FATAL, __VA_ARGS__)
 #define mp_err(log, ...)        mp_msg(log, MSGL_ERR, __VA_ARGS__)