Reserve some third-party API messages to debug logging

FFmpegthumbnailer is known to be really verbose, and we don't have a
priori control on the messages that can be displayed by external
thumbnailers (it can be in particular FFmpegthumbnailer).

Fixes #10, related to #29.

2 files changed, 39 insertions, 0 deletions

diff --git a/tumbler/tumbler-util.c b/tumbler/tumbler-util.c
index 04c434d..cfc1172 100644
--- a/tumbler/tumbler-util.c
+++ b/tumbler/tumbler-util.c
@@ -85,6 +85,43 @@ tumbler_util_dump_strv (const gchar *log_domain,
 
 
 
+/*
+ * This is intended to be used around too verbose third-party APIs we can't silence by
+ * another means:
+ *   tumbler_util_toggle_stderr (G_LOG_DOMAIN);
+ *   … = too_verbose_api (…);
+ *   tumbler_util_toggle_stderr (G_LOG_DOMAIN);
+ * When debug logging is enabled, it does nothing.
+ */
+void
+tumbler_util_toggle_stderr (const gchar *log_domain)
+{
+  static gint stderr_save = -2;
+
+  /* do nothing in case of previous error or if debug logging is enabled */
+  if (stderr_save == -1 || tumbler_util_is_debug_logging_enabled (log_domain))
+    return;
+
+  /* redirect stderr to /dev/null */
+  if (stderr_save == -2)
+    {
+      fflush (stderr);
+      stderr_save = dup (STDERR_FILENO);
+      if (stderr_save != -1 && freopen ("/dev/null", "a", stderr) == NULL)
+        stderr_save = -1;
+    }
+  /* restore stderr to stderr_save */
+  else
+    {
+      fflush (stderr);
+      stderr_save = dup2 (stderr_save, STDERR_FILENO);
+      if (stderr_save != -1)
+        stderr_save = -2;
+    }
+}
+
+
+
 gchar **
 tumbler_util_get_supported_uri_schemes (void)
 {
diff --git a/tumbler/tumbler-util.h b/tumbler/tumbler-util.h
index 20a0cc3..24c7d29 100644
--- a/tumbler/tumbler-util.h
+++ b/tumbler/tumbler-util.h
@@ -34,6 +34,8 @@ void tumbler_util_dump_strv (const gchar *log_domain,
                              const gchar *label,
                              const gchar *const *strv);
 
+void tumbler_util_toggle_stderr (const gchar *log_domain);
+
 gchar **tumbler_util_get_supported_uri_schemes (void) G_GNUC_MALLOC;
 
 GKeyFile *tumbler_util_get_settings (void) G_GNUC_MALLOC;