[geary/mjog/logging-improvements: 17/23] Geary.Logging: Let callers determine threading safety for log_listener

[Michael Gratton <mjog src gnome org>]

commit 2fada87a72b469fff7ff81d8b86484bf31585139
Author: Michael Gratton <mike vee net>
Date:   Thu Apr 16 17:11:53 2020 +1000

    Geary.Logging: Let callers determine threading safety for log_listener
    
    Rather than scheduling calling a registered log_listener on the default
    main loop context, let the listener implementation handle that in
    whatever way they want.

 src/engine/util/util-logging.vala | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)
---
diff --git a/src/engine/util/util-logging.vala b/src/engine/util/util-logging.vala
index e6c1cb90..5294355b 100644
--- a/src/engine/util/util-logging.vala
+++ b/src/engine/util/util-logging.vala
@@ -62,6 +62,9 @@ namespace Geary.Logging {
      * For any log records to be created, {@link default_log_writer}
      * must be set as the GLib structured log writer.
      *
+     * Note that the given function *must* be thread-safe, since
+     * logging can occur on multiple threads at once.
+     *
      * @see default_log_writer
      */
     public void set_log_listener(LogRecord? new_listener) {
@@ -235,13 +238,8 @@ namespace Geary.Logging {
             // records.
             old_record = null;
 
-            // Ensure the listener is updated on the main loop only, since
-            // this could be getting called from other threads.
             if (Logging.listener != null) {
-                GLib.MainContext.default().invoke(() => {
-                        Logging.listener(record);
-                        return GLib.Source.REMOVE;
-                    });
+                Logging.listener(record);
             }
 
             write_record(record, levels);