[mutter] native: Replace 'headless' property with 'mode' property

[Marge Bot <marge-bot src gnome org>]

commit 124a1582e1d1585fef2167285998f519fcc40f35
Author: Jonas Ådahl <jadahl gmail com>
Date:   Mon May 17 19:13:40 2021 +0200

    native: Replace 'headless' property with 'mode' property
    
    There will be another mode added later, 'test'; prepare for this by
    changing the existing "mode" boolean ('headless') to a mode, which is
    either 'default' or 'headless'. Checking the is_headless variable is
    changed to using the function is_headless(), except for one place, being
    VT switching, which in preparation is only allowed on the 'default'
    mode. Other places where it makes sense, the conditions are changed to
    switch statements.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2151>

 src/backends/native/meta-backend-native-types.h |  6 +++
 src/backends/native/meta-backend-native.c       | 62 ++++++++++++++++---------
 src/core/meta-context-main.c                    |  2 +-
 src/tests/meta-context-test.c                   |  2 +-
 4 files changed, 47 insertions(+), 25 deletions(-)
---
diff --git a/src/backends/native/meta-backend-native-types.h b/src/backends/native/meta-backend-native-types.h
index f6c87484be..a8c4dd544d 100644
--- a/src/backends/native/meta-backend-native-types.h
+++ b/src/backends/native/meta-backend-native-types.h
@@ -39,4 +39,10 @@ typedef enum _MetaSeatNativeFlag
   META_SEAT_NATIVE_FLAG_NO_LIBINPUT = 1 << 0,
 } MetaSeatNativeFlag;
 
+typedef enum _MetaBackendNativeMode
+{
+  META_BACKEND_NATIVE_MODE_DEFAULT = 0,
+  META_BACKEND_NATIVE_MODE_HEADLESS,
+} MetaBackendNativeMode;
+
 #endif /* META_BACKEND_NATIVE_TYPES_H */
diff --git a/src/backends/native/meta-backend-native.c b/src/backends/native/meta-backend-native.c
index 0cbe40d87d..be133b1003 100644
--- a/src/backends/native/meta-backend-native.c
+++ b/src/backends/native/meta-backend-native.c
@@ -66,11 +66,13 @@
 #include "backends/meta-screen-cast.h"
 #endif
 
+#include "meta-private-enum-types.h"
+
 enum
 {
   PROP_0,
 
-  PROP_HEADLESS,
+  PROP_MODE,
 
   N_PROPS
 };
@@ -86,7 +88,7 @@ struct _MetaBackendNative
   MetaUdev *udev;
   MetaKms *kms;
 
-  gboolean is_headless;
+  MetaBackendNativeMode mode;
 };
 
 static GInitableIface *initable_parent_iface;
@@ -254,10 +256,12 @@ meta_backend_native_create_monitor_manager (MetaBackend *backend,
 {
   MetaBackendNative *backend_native = META_BACKEND_NATIVE (backend);
   MetaMonitorManager *manager;
+  gboolean needs_outputs;
 
+  needs_outputs = !(backend_native->mode & META_BACKEND_NATIVE_MODE_HEADLESS);
   manager = g_initable_new (META_TYPE_MONITOR_MANAGER_NATIVE, NULL, error,
                             "backend", backend,
-                            "needs-outputs", !backend_native->is_headless,
+                            "needs-outputs", needs_outputs,
                             NULL);
   if (!manager)
     return NULL;
@@ -372,16 +376,22 @@ meta_backend_native_lock_layout_group (MetaBackend *backend,
 const char *
 meta_backend_native_get_seat_id (MetaBackendNative *backend_native)
 {
-  if (backend_native->is_headless)
-    return "seat0";
-  else
-    return meta_launcher_get_seat_id (backend_native->launcher);
+  switch (backend_native->mode)
+    {
+    case META_BACKEND_NATIVE_MODE_DEFAULT:
+      return meta_launcher_get_seat_id (backend_native->launcher);
+    case META_BACKEND_NATIVE_MODE_HEADLESS:
+      return "seat0";
+    }
+  g_assert_not_reached ();
 }
 
 static gboolean
 meta_backend_native_is_headless (MetaBackend *backend)
 {
-  return META_BACKEND_NATIVE (backend)->is_headless;
+  MetaBackendNative *backend_native = META_BACKEND_NATIVE (backend);
+
+  return backend_native->mode == META_BACKEND_NATIVE_MODE_HEADLESS;
 }
 
 static void
@@ -537,7 +547,7 @@ init_gpus (MetaBackendNative  *native,
 
   g_list_free_full (devices, g_object_unref);
 
-  if (!native->is_headless &&
+  if (!meta_backend_is_headless (backend) &&
       g_list_length (meta_backend_get_gpus (backend)) == 0)
     {
       g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND,
@@ -558,6 +568,7 @@ meta_backend_native_initable_init (GInitable     *initable,
                                    GError       **error)
 {
   MetaBackendNative *native = META_BACKEND_NATIVE (initable);
+  MetaBackend *backend = META_BACKEND (native);
   MetaKmsFlags kms_flags;
 
   if (!meta_is_stage_views_enabled ())
@@ -567,7 +578,7 @@ meta_backend_native_initable_init (GInitable     *initable,
       return FALSE;
     }
 
-  if (!native->is_headless)
+  if (!meta_backend_is_headless (backend))
     {
       native->launcher = meta_launcher_new (error);
       if (!native->launcher)
@@ -578,7 +589,7 @@ meta_backend_native_initable_init (GInitable     *initable,
   native->udev = meta_udev_new (native);
 
   kms_flags = META_KMS_FLAG_NONE;
-  if (native->is_headless)
+  if (meta_backend_is_headless (backend))
     kms_flags |= META_KMS_FLAG_NO_MODE_SETTING;
 
   native->kms = meta_kms_new (META_BACKEND (native), kms_flags, error);
@@ -601,8 +612,8 @@ meta_backend_native_set_property (GObject      *object,
 
   switch (prop_id)
     {
-    case PROP_HEADLESS:
-      backend_native->is_headless = g_value_get_boolean (value);
+    case PROP_MODE:
+      backend_native->mode = g_value_get_enum (value);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
@@ -649,14 +660,15 @@ meta_backend_native_class_init (MetaBackendNativeClass *klass)
 
   backend_class->is_headless = meta_backend_native_is_headless;
 
-  obj_props[PROP_HEADLESS] =
-    g_param_spec_boolean ("headless",
-                          "headless",
-                          "Headless",
-                          FALSE,
-                          G_PARAM_WRITABLE |
-                          G_PARAM_CONSTRUCT_ONLY |
-                          G_PARAM_STATIC_STRINGS);
+  obj_props[PROP_MODE] =
+    g_param_spec_enum ("mode",
+                       "mode",
+                       "mode",
+                       META_TYPE_BACKEND_NATIVE_MODE,
+                       META_BACKEND_NATIVE_MODE_DEFAULT,
+                       G_PARAM_WRITABLE |
+                       G_PARAM_CONSTRUCT_ONLY |
+                       G_PARAM_STATIC_STRINGS);
   g_object_class_install_properties (object_class, N_PROPS, obj_props);
 }
 
@@ -696,14 +708,18 @@ meta_activate_vt (int vt, GError **error)
   MetaBackendNative *native = META_BACKEND_NATIVE (backend);
   MetaLauncher *launcher = meta_backend_native_get_launcher (native);
 
-  if (native->is_headless)
+  switch (native->mode)
     {
+    case META_BACKEND_NATIVE_MODE_DEFAULT:
+      return meta_launcher_activate_vt (launcher, vt, error);
+    case META_BACKEND_NATIVE_MODE_HEADLESS:
+    case META_BACKEND_NATIVE_MODE_TEST:
       g_set_error (error, G_IO_ERROR, G_IO_ERROR_FAILED,
                    "Can't switch VT while headless");
       return FALSE;
     }
 
-  return meta_launcher_activate_vt (launcher, vt, error);
+  g_assert_not_reached ();
 }
 
 void
diff --git a/src/core/meta-context-main.c b/src/core/meta-context-main.c
index a81ea9f9f1..fe11b4bb6f 100644
--- a/src/core/meta-context-main.c
+++ b/src/core/meta-context-main.c
@@ -438,7 +438,7 @@ create_headless_backend (MetaContext  *context,
   return g_initable_new (META_TYPE_BACKEND_NATIVE,
                          NULL, error,
                          "context", context,
-                         "headless", TRUE,
+                         "mode", META_BACKEND_NATIVE_MODE_HEADLESS,
                          NULL);
 }
 
diff --git a/src/tests/meta-context-test.c b/src/tests/meta-context-test.c
index 863c20a98c..08acdcb73e 100644
--- a/src/tests/meta-context-test.c
+++ b/src/tests/meta-context-test.c
@@ -159,7 +159,7 @@ create_headless_backend (MetaContext  *context,
   return g_initable_new (META_TYPE_BACKEND_NATIVE,
                          NULL, error,
                          "context", context,
-                         "headless", TRUE,
+                         "mode", META_BACKEND_NATIVE_MODE_HEADLESS,
                          NULL);
 }
 #endif /* HAVE_NATIVE_BACKEND */