cinnamon-global.c: Add the capability to print the js stack when a

C critical or warning occurs.

This is useful for some difficult-to-trace library warnings that
are triggered by JS code.

ref:
0aae4bc

Author: mtwebster

src/cinnamon-global.c

@@ -19,6 +19,16 @@
 #define GNOME_DESKTOP_USE_UNSTABLE_API
 #include <libcinnamon-desktop/gnome-systemd.h>
 
+// Warnings generated by C libraries (clutter, muffin, glib, etc...) can be
+// difficult to trace when they originate at the javascript level.
+//
+// Enabling (1) will print the current js call stack after the warning is logged.
+// Note, this may result in the stack being printed twice in some instances, as we
+// already do this for specific warnings elsewhere. It may be nicer to get rid of
+// those others (in cjs and st-widget I think) and permanently enable the logging
+// here.
+#define PRINT_JS_STACK_FOR_C_WARNINGS 0
+
 static CinnamonGlobal *the_object = NULL;
 
 enum {
@@ -60,6 +70,8 @@ G_DEFINE_TYPE(CinnamonGlobal, cinnamon_global, G_TYPE_OBJECT);
 
 static guint cinnamon_global_signals [LAST_SIGNAL] = { 0 };
 
+static void setup_log_handler (CinnamonGlobal *global);
+
 static void
 cinnamon_global_set_property(GObject         *object,
                           guint            prop_id,
@@ -234,6 +246,8 @@ cinnamon_global_init (CinnamonGlobal *global)
 
   global->settings = g_settings_new ("org.cinnamon");
 
+  setup_log_handler (global);
+
   setup_notifications_service (global);
 
   global->ui_scale = 1;
@@ -908,6 +922,28 @@ _cinnamon_global_get_gjs_context (CinnamonGlobal *global)
   return global->js_context;
 }
 
+static void
+log_handler (const char *domain,
+             GLogLevelFlags level,
+             const char *message,
+             gpointer data)
+{
+    g_log_default_handler (domain, level, message, data);
+
+    if ((level & (G_LOG_LEVEL_CRITICAL | G_LOG_LEVEL_WARNING)) != 0) {
+        gjs_dumpstack ();
+    }
+}
+
+static void
+setup_log_handler (CinnamonGlobal *global)
+{
+    if (!PRINT_JS_STACK_FOR_C_WARNINGS)
+        return;
+
+    g_log_set_default_handler (log_handler, NULL);
+}
+
 static guint32
 get_current_time_maybe_roundtrip (CinnamonGlobal *global)
 {