[glib] giomodule: Allow overriding source directory gio modules are loaded from

[Matthias Clasen <matthiasc src gnome org>]

commit e3babb368742f6f8b69ba2c8a2b9a95d6142e8ff
Author: Stef Walter <stefw gnome org>
Date:   Fri Nov 8 14:26:33 2013 +0100

    giomodule: Allow overriding source directory gio modules are loaded from
    
    When testing (and valgrinding) we need to have a known set of modules
    loaded.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=711801

 docs/reference/gio/overview.xml |   12 +++++++++++-
 gio/giomodule.c                 |    7 ++++++-
 2 files changed, 17 insertions(+), 2 deletions(-)
---
diff --git a/docs/reference/gio/overview.xml b/docs/reference/gio/overview.xml
index dcb1bdb..a72bcc6 100644
--- a/docs/reference/gio/overview.xml
+++ b/docs/reference/gio/overview.xml
@@ -363,12 +363,22 @@ Gvfs is also heavily distributed and relies on a session bus to be present.
     </formalpara>
 
     <formalpara>
+      <title><envar>GIO_MODULE_DIR</envar></title>
+
+      <para>
+        When this environment variable is set to a path, GIO will load
+       modules from this alternate directory instead of the directory
+       built into GIO. This is useful when running tests, for example.
+      </para>
+    </formalpara>
+
+    <formalpara>
       <title><envar>GIO_EXTRA_MODULES</envar></title>
 
       <para>
         When this environment variable is set to a path, or a set of
         paths separated by a colon, GIO will attempt to load
-        modules from within the path.
+        additional modules from within the path.
       </para>
     </formalpara>
 
diff --git a/gio/giomodule.c b/gio/giomodule.c
index 17d55de..2498659 100644
--- a/gio/giomodule.c
+++ b/gio/giomodule.c
@@ -1017,6 +1017,7 @@ _g_io_modules_ensure_loaded (void)
   static gboolean loaded_dirs = FALSE;
   const char *module_path;
   GIOModuleScope *scope;
+  const gchar *module_dir;
 
   _g_io_modules_ensure_extension_points_registered ();
   
@@ -1045,7 +1046,11 @@ _g_io_modules_ensure_loaded (void)
        }
 
       /* Then load the compiled in path */
-      g_io_modules_scan_all_in_directory_with_scope (GIO_MODULE_DIR, scope);
+      module_dir = g_getenv ("GIO_MODULE_DIR");
+      if (module_dir == NULL)
+        module_dir = GIO_MODULE_DIR;
+
+      g_io_modules_scan_all_in_directory_with_scope (module_dir, scope);
 
       g_io_module_scope_free (scope);