[gnome-builder] meson: fix path to meson.build when setting :project-file

[Christian Hergert <chergert src gnome org>]

commit 1a28d404164593e57153080bf8c957647eb4d342
Author: Christian Hergert <chergert redhat com>
Date:   Mon Jan 14 13:22:14 2019 -0800

    meson: fix path to meson.build when setting :project-file
    
    Fixes #755

 src/plugins/meson/gbp-meson-build-system.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)
---
diff --git a/src/plugins/meson/gbp-meson-build-system.c b/src/plugins/meson/gbp-meson-build-system.c
index 7961bbf6a..8e74998a1 100644
--- a/src/plugins/meson/gbp-meson-build-system.c
+++ b/src/plugins/meson/gbp-meson-build-system.c
@@ -346,6 +346,24 @@ gbp_meson_build_system_load_commands_finish (GbpMesonBuildSystem  *self,
   return ide_task_propagate_pointer (IDE_TASK (result), error);
 }
 
+static void
+gbp_meson_build_system_set_project_file (GbpMesonBuildSystem *self,
+                                         GFile               *file)
+{
+  g_autofree gchar *name = NULL;
+
+  g_assert (IDE_IS_MAIN_THREAD ());
+  g_assert (GBP_IS_MESON_BUILD_SYSTEM (self));
+  g_assert (G_IS_FILE (file));
+
+  name = g_file_get_basename (file);
+
+  if (ide_str_equal0 (name, "meson.build"))
+    self->project_file = g_file_dup (file);
+  else
+    self->project_file = g_file_get_child (file, "meson.build");
+}
+
 static void
 gbp_meson_build_system_finalize (GObject *object)
 {
@@ -389,7 +407,7 @@ gbp_meson_build_system_set_property (GObject      *object,
   switch (prop_id)
     {
     case PROP_PROJECT_FILE:
-      self->project_file = g_value_dup_object (value);
+      gbp_meson_build_system_set_project_file (self, g_value_get_object (value));
       break;
 
     default: