[libadwaita/wip/exalm/empty] main: Load stylesheet in a separate provider instead of gtk theme

[Alexander Mikhaylenko <alexm src gnome org>]

commit 07840bd7d56e0c11ee00bccab1d835d1590fbdc7
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Tue May 18 22:57:32 2021 +0500

    main: Load stylesheet in a separate provider instead of gtk theme

 src/adw-main.c                                   | 40 ++++++++++++++++++------
 src/stylesheet/adwaita-stylesheet.gresources.xml | 26 +++------------
 src/stylesheet/empty.css                         |  0
 3 files changed, 34 insertions(+), 32 deletions(-)
---
diff --git a/src/adw-main.c b/src/adw-main.c
index 2c9e3a5a..1b3493d3 100644
--- a/src/adw-main.c
+++ b/src/adw-main.c
@@ -10,6 +10,7 @@
 #include <gtk/gtk.h>
 
 static int adw_initialized = FALSE;
+static GtkCssProvider *provider;
 
 static gboolean
 is_high_contrast (void)
@@ -29,26 +30,37 @@ is_high_contrast (void)
          !g_strcmp0 (theme_name, "HighContrastInverse");
 }
 
+static void
+load_theme (gboolean dark,
+            gboolean high_contrast)
+{
+  g_autofree char *path = NULL;
+  const char *variant;
+
+  if (high_contrast)
+    variant = dark ? "hc-dark" : "hc";
+  else
+    variant = dark ? "dark" : "light";
+
+  path = g_strdup_printf ("/org/gtk/libgtk/theme/Adwaita/Adwaita-%s.css", variant);
+
+  gtk_css_provider_load_from_resource (provider, path);
+}
+
 static void
 update_theme (void)
 {
   GtkSettings *settings = gtk_settings_get_default ();
-  g_autofree char *new_theme_name = NULL;
   gboolean prefer_dark_theme;
-  const char *variant;
 
   g_object_get (settings,
                 "gtk-application-prefer-dark-theme", &prefer_dark_theme,
                 NULL);
 
-  if (is_high_contrast ())
-    variant = prefer_dark_theme ? "hc-dark" : "hc";
-  else
-    variant = prefer_dark_theme ? "dark" : "light";
+  // Empty doesn't have a gtk-dark.css so we'll make our own instead
+  g_object_set (settings, "gtk-theme-name", "Adwaita", NULL);
 
-  new_theme_name = g_strdup_printf ("Adwaita-%s", variant);
-
-  g_object_set (settings, "gtk-theme-name", new_theme_name, NULL);
+  load_theme (prefer_dark_theme, is_high_contrast ());
 }
 
 static void
@@ -64,6 +76,7 @@ adw_style_init (void)
 {
   static gsize guard = 0;
   GtkSettings *settings;
+  GdkDisplay *display;
 
   if (!g_once_init_enter (&guard))
     return;
@@ -76,6 +89,13 @@ adw_style_init (void)
     return;
   }
 
+  display = gdk_display_get_default ();
+
+  provider = gtk_css_provider_new ();
+  gtk_style_context_add_provider_for_display (display,
+                                              GTK_STYLE_PROVIDER (provider),
+                                              GTK_STYLE_PROVIDER_PRIORITY_THEME);
+
   g_signal_connect (settings,
                     "notify::gtk-application-prefer-dark-theme",
                     G_CALLBACK (update_theme),
@@ -83,7 +103,7 @@ adw_style_init (void)
 
   /* If gtk_settings_get_default() has worked, GdkDisplay
    * exists, so we don't need to check that separately. */
-  g_signal_connect (gdk_display_get_default (),
+  g_signal_connect (display,
                     "setting-changed",
                     G_CALLBACK (setting_changed_cb),
                     NULL);
diff --git a/src/stylesheet/adwaita-stylesheet.gresources.xml 
b/src/stylesheet/adwaita-stylesheet.gresources.xml
index feb16bdf..98f36aca 100644
--- a/src/stylesheet/adwaita-stylesheet.gresources.xml
+++ b/src/stylesheet/adwaita-stylesheet.gresources.xml
@@ -1,28 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <gresources>
-  <gresource prefix="/org/gtk/libgtk/theme/Adwaita-light">
-    <file alias='gtk.css'>gtk-light.css</file>
-  </gresource>
-
-  <gresource prefix="/org/gtk/libgtk/theme/Adwaita-dark">
-    <file alias='gtk.css'>gtk-dark.css</file>
-    <file alias='gtk-dark.css'>gtk-dark.css</file>
-  </gresource>
-
-  <gresource prefix="/org/gtk/libgtk/theme/Adwaita-hc">
-    <file alias='gtk.css'>gtk-hc.css</file>
-  </gresource>
-
-  <gresource prefix="/org/gtk/libgtk/theme/Adwaita-hc-dark">
-    <file alias='gtk.css'>gtk-hc-dark.css</file>
-    <file alias='gtk-dark.css'>gtk-hc-dark.css</file>
-  </gresource>
-
   <gresource prefix="/org/gtk/libgtk/theme/Adwaita">
-    <file>gtk.css</file>
-    <file>gtk-light.css</file>
-    <file>gtk-hc.css</file>
-    <file>gtk-hc-dark.css</file>
+    <file alias='gtk.css'>empty.css</file>
+    <file alias='gtk-dark.css'>empty.css</file>
+    <file alias='gtk-hc.css'>empty.css</file>
+    <file alias='gtk-hc-dark.css'>empty.css</file>
 
     <file>Adwaita-light.css</file>
     <file>Adwaita-dark.css</file>
diff --git a/src/stylesheet/empty.css b/src/stylesheet/empty.css
new file mode 100644
index 00000000..e69de29b