[libadwaita/wip/exalm/dark: 2/5] Add AdwStyleManager

[Alexander Mikhaylenko <alexm src gnome org>]

commit be7f573e77019ffee6d7769dd2364eeead6e6331
Author: Alexander Mikhaylenko <exalm7659 gmail com>
Date:   Thu Aug 26 14:21:34 2021 +0500

    Add AdwStyleManager
    
    Move the stylesheet handling from adw-main.c there. Provide API for
    influencing and inspecting color scheme.

 src/adw-enums.c.in      |   1 +
 src/adw-main.c          |  76 +-----------
 src/adw-style-manager.c | 300 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/adw-style-manager.h |  48 ++++++++
 src/adwaita.h           |   1 +
 src/meson.build         |   2 +
 6 files changed, 357 insertions(+), 71 deletions(-)
---
diff --git a/src/adw-enums.c.in b/src/adw-enums.c.in
index 238a7283..b151b1ed 100644
--- a/src/adw-enums.c.in
+++ b/src/adw-enums.c.in
@@ -8,6 +8,7 @@
 #include "adw-leaflet.h"
 #include "adw-navigation-direction.h"
 #include "adw-squeezer.h"
+#include "adw-style-manager.h"
 #include "adw-view-switcher.h"
 
 /*** END file-header ***/
diff --git a/src/adw-main.c b/src/adw-main.c
index afad88e0..e3a445d1 100644
--- a/src/adw-main.c
+++ b/src/adw-main.c
@@ -4,91 +4,25 @@
  * SPDX-License-Identifier: LGPL-2.1-or-later
  */
 #include "config.h"
+
 #include "adw-main-private.h"
-#include <gio/gio.h>
+
+#include "adw-style-manager.h"
 #include <glib/gi18n-lib.h>
 #include <gtk/gtk.h>
 
 static int adw_initialized = FALSE;
 
-static gboolean
-is_high_contrast (void)
-{
-  GdkDisplay *display = gdk_display_get_default ();
-  g_auto (GValue) value = G_VALUE_INIT;
-  const char *theme_name;
-
-  g_value_init (&value, G_TYPE_STRING);
-  if (!gdk_display_get_setting (display, "gtk-theme-name", &value))
-    return FALSE;
-
-  theme_name = g_value_get_string (&value);
-
-  /* TODO: HighContrast shouldn't be a theme */
-  return !g_strcmp0 (theme_name, "HighContrast") ||
-         !g_strcmp0 (theme_name, "HighContrastInverse");
-}
-
-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";
-
-  new_theme_name = g_strdup_printf ("Adwaita-%s", variant);
-
-  g_object_set (settings, "gtk-theme-name", new_theme_name, NULL);
-}
-
-static void
-setting_changed_cb (GdkDisplay *display,
-                    const char *setting)
-{
-  if (!g_strcmp0 (setting, "gtk-theme-name"))
-    update_theme ();
-}
-
 static void
 adw_style_init (void)
 {
   static gsize guard = 0;
-  GtkSettings *settings;
 
   if (!g_once_init_enter (&guard))
     return;
 
-  settings = gtk_settings_get_default ();
-
-  if (!settings) {
-    g_once_init_leave (&guard, 1);
-
-    return;
-  }
-
-  g_signal_connect (settings,
-                    "notify::gtk-application-prefer-dark-theme",
-                    G_CALLBACK (update_theme),
-                    NULL);
-
-  /* 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 (),
-                    "setting-changed",
-                    G_CALLBACK (setting_changed_cb),
-                    NULL);
-
-  update_theme ();
+  /* Ensure AdwStyleManager is initialized */
+  adw_style_manager_get_default ();
 
   g_once_init_leave (&guard, 1);
 }
diff --git a/src/adw-style-manager.c b/src/adw-style-manager.c
new file mode 100644
index 00000000..ba846bdc
--- /dev/null
+++ b/src/adw-style-manager.c
@@ -0,0 +1,300 @@
+/*
+ * Copyright (C) 2021 Purism SPC
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ *
+ * Author: Alexander Mikhaylenko <alexander mikhaylenko puri sm>
+ */
+
+#include "config.h"
+
+#include "adw-style-manager.h"
+
+#include "adw-settings-private.h"
+#include <gtk/gtk.h>
+
+/**
+ * AdwColorScheme:
+ * @ADW_COLOR_SCHEME_LIGHT: TODO
+ * @ADW_COLOR_SCHEME_LIGHT_DARK: TODO
+ * @ADW_COLOR_SCHEME_DARK_LIGHT: TODO
+ * @ADW_COLOR_SCHEME_DARK: TODO
+ *
+ * TODO
+ *
+ * Since: 1.0
+ */
+
+/**
+ * AdwStyleManager:
+ *
+ * TODO
+ *
+ * Since: 1.0
+ */
+
+struct _AdwStyleManager
+{
+  GObject parent_instance;
+
+  AdwSettings *settings;
+
+  AdwColorScheme color_scheme;
+  gboolean dark;
+};
+
+G_DEFINE_TYPE (AdwStyleManager, adw_style_manager, G_TYPE_OBJECT);
+
+enum {
+  PROP_0,
+  PROP_COLOR_SCHEME,
+  PROP_DARK,
+  PROP_HIGH_CONTRAST,
+  LAST_PROP,
+};
+
+static GParamSpec *props[LAST_PROP];
+
+static AdwStyleManager *default_instance;
+
+static void
+update_stylesheet (AdwStyleManager *self)
+{
+  const char *variant;
+  g_autofree char *new_theme_name = NULL;
+
+  if (adw_settings_get_high_contrast (self->settings))
+    variant = self->dark ? "hc-dark" : "hc";
+  else
+    variant = self->dark ? "dark" : "light";
+
+  new_theme_name = g_strdup_printf ("Adwaita-%s", variant);
+
+  g_object_set (gtk_settings_get_default (), "gtk-theme-name", new_theme_name, NULL);
+}
+
+static gboolean
+get_is_dark (AdwStyleManager *self)
+{
+  AdwSystemColorScheme system_scheme = adw_settings_get_color_scheme (self->settings);
+
+  switch (self->color_scheme) {
+  case ADW_COLOR_SCHEME_LIGHT:
+    return FALSE;
+  case ADW_COLOR_SCHEME_LIGHT_DARK:
+    return (system_scheme == ADW_SYSTEM_COLOR_SCHEME_PREFER_DARK);
+  case ADW_COLOR_SCHEME_DARK_LIGHT:
+    return (system_scheme == ADW_SYSTEM_COLOR_SCHEME_PREFER_DARK) ||
+           (system_scheme == ADW_SYSTEM_COLOR_SCHEME_DEFAULT);
+  case ADW_COLOR_SCHEME_DARK:
+    return TRUE;
+  default:
+    g_assert_not_reached ();
+  }
+}
+
+static void
+update_dark (AdwStyleManager *self)
+{
+  gboolean dark = get_is_dark (self);
+
+  if (dark == self->dark)
+    return;
+
+  self->dark = dark;
+
+  update_stylesheet (self);
+
+  g_object_notify_by_pspec (G_OBJECT (self), props[PROP_DARK]);
+}
+
+static void
+notify_high_contrast_cb (AdwStyleManager *self)
+{
+  update_stylesheet (self);
+
+  g_object_notify_by_pspec (G_OBJECT (self), props[PROP_HIGH_CONTRAST]);
+}
+
+static void
+adw_style_manager_constructed (GObject *object)
+{
+  AdwStyleManager *self = ADW_STYLE_MANAGER (object);
+
+  G_OBJECT_CLASS (adw_style_manager_parent_class)->constructed (object);
+
+  self->settings = adw_settings_get_default ();
+
+  g_signal_connect_swapped (self->settings,
+                            "notify::color-scheme",
+                            G_CALLBACK (update_dark),
+                            self);
+  g_signal_connect_swapped (self->settings,
+                            "notify::high-contrast",
+                            G_CALLBACK (notify_high_contrast_cb),
+                            self);
+
+  self->dark = get_is_dark (self);
+
+  update_stylesheet (self);
+}
+
+static void
+adw_style_manager_dispose (GObject *object)
+{
+  AdwStyleManager *self = ADW_STYLE_MANAGER (object);
+
+  if (self->settings) {
+    g_signal_handlers_disconnect_by_func (self->settings,
+                                          G_CALLBACK (update_dark),
+                                          self);
+    self->settings = NULL;
+  }
+
+  G_OBJECT_CLASS (adw_style_manager_parent_class)->dispose (object);
+}
+
+static void
+adw_style_manager_get_property (GObject    *object,
+                                guint       prop_id,
+                                GValue     *value,
+                                GParamSpec *pspec)
+{
+  AdwStyleManager *self = ADW_STYLE_MANAGER (object);
+
+  switch (prop_id) {
+  case PROP_COLOR_SCHEME:
+    g_value_set_enum (value, adw_style_manager_get_color_scheme (self));
+    break;
+
+  case PROP_DARK:
+    g_value_set_boolean (value, adw_style_manager_get_dark (self));
+    break;
+
+    case PROP_HIGH_CONTRAST:
+    g_value_set_boolean (value, adw_style_manager_get_high_contrast (self));
+    break;
+
+  default:
+    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+  }
+}
+
+static void
+adw_style_manager_set_property (GObject      *object,
+                                guint         prop_id,
+                                const GValue *value,
+                                GParamSpec   *pspec)
+{
+  AdwStyleManager *self = ADW_STYLE_MANAGER (object);
+
+  switch (prop_id) {
+  case PROP_COLOR_SCHEME:
+    adw_style_manager_set_color_scheme (self, g_value_get_enum (value));
+    break;
+
+  default:
+    G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+  }
+}
+
+static void
+adw_style_manager_class_init (AdwStyleManagerClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->constructed = adw_style_manager_constructed;
+  object_class->dispose = adw_style_manager_dispose;
+  object_class->get_property = adw_style_manager_get_property;
+  object_class->set_property = adw_style_manager_set_property;
+
+  props[PROP_COLOR_SCHEME] =
+    g_param_spec_enum ("color-scheme",
+                       "Color Scheme",
+                       "Color Scheme",
+                       ADW_TYPE_COLOR_SCHEME,
+                       ADW_COLOR_SCHEME_LIGHT,
+                       G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY);
+
+  props[PROP_DARK] =
+    g_param_spec_boolean ("dark",
+                          "Dark",
+                          "Dark",
+                          FALSE,
+                          G_PARAM_READABLE);
+
+  props[PROP_HIGH_CONTRAST] =
+    g_param_spec_boolean ("high-contrast",
+                          "High Contrast",
+                          "High Contrast",
+                          FALSE,
+                          G_PARAM_READABLE);
+
+  g_object_class_install_properties (object_class, LAST_PROP, props);
+}
+
+static void
+adw_style_manager_init (AdwStyleManager *self)
+{
+}
+
+/**
+ * adw_style_manager_get_default:
+ *
+ * Gets an `AdwStyleManager` singleton instance.
+ *
+ * Returns: (transfer none): the `AdwStyleManager`
+ *
+ * Since: 1.6
+ */
+AdwStyleManager *
+adw_style_manager_get_default (void)
+{
+  if (!default_instance)
+    default_instance = g_object_new (ADW_TYPE_STYLE_MANAGER, NULL);
+
+  return default_instance;
+}
+
+AdwColorScheme
+adw_style_manager_get_color_scheme (AdwStyleManager *self)
+{
+  g_return_val_if_fail (ADW_IS_STYLE_MANAGER (self), ADW_COLOR_SCHEME_LIGHT);
+
+  return self->color_scheme;
+}
+
+void
+adw_style_manager_set_color_scheme (AdwStyleManager *self,
+                                    AdwColorScheme   color_scheme)
+{
+  g_return_if_fail (ADW_IS_STYLE_MANAGER (self));
+
+  if (color_scheme == self->color_scheme)
+    return;
+
+  self->color_scheme = color_scheme;
+
+  g_object_freeze_notify (G_OBJECT (self));
+
+  g_object_notify_by_pspec (G_OBJECT (self), props[PROP_COLOR_SCHEME]);
+  update_dark (self);
+
+  g_object_thaw_notify (G_OBJECT (self));
+}
+
+gboolean
+adw_style_manager_get_high_contrast (AdwStyleManager *self)
+{
+  g_return_val_if_fail (ADW_IS_STYLE_MANAGER (self), FALSE);
+
+  return adw_settings_get_high_contrast (self->settings);
+}
+
+gboolean
+adw_style_manager_get_dark (AdwStyleManager *self)
+{
+  g_return_val_if_fail (ADW_IS_STYLE_MANAGER (self), FALSE);
+
+  return self->dark;
+}
diff --git a/src/adw-style-manager.h b/src/adw-style-manager.h
new file mode 100644
index 00000000..b33d773c
--- /dev/null
+++ b/src/adw-style-manager.h
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2021 Purism SPC
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ *
+ * Author: Alexander Mikhaylenko <alexander mikhaylenko puri sm>
+ */
+
+#pragma once
+
+#if !defined(_ADWAITA_INSIDE) && !defined(ADWAITA_COMPILATION)
+#error "Only <adwaita.h> can be included directly."
+#endif
+
+#include "adw-version.h"
+
+#include <glib-object.h>
+#include "adw-enums.h"
+
+G_BEGIN_DECLS
+
+typedef enum {
+  ADW_COLOR_SCHEME_LIGHT,
+  ADW_COLOR_SCHEME_LIGHT_DARK,
+  ADW_COLOR_SCHEME_DARK_LIGHT,
+  ADW_COLOR_SCHEME_DARK,
+} AdwColorScheme;
+
+#define ADW_TYPE_STYLE_MANAGER (adw_style_manager_get_type())
+
+ADW_AVAILABLE_IN_ALL
+G_DECLARE_FINAL_TYPE (AdwStyleManager, adw_style_manager, ADW, STYLE_MANAGER, GObject)
+
+ADW_AVAILABLE_IN_ALL
+AdwStyleManager *adw_style_manager_get_default (void);
+
+ADW_AVAILABLE_IN_ALL
+AdwColorScheme adw_style_manager_get_color_scheme (AdwStyleManager *self);
+ADW_AVAILABLE_IN_ALL
+void           adw_style_manager_set_color_scheme (AdwStyleManager *self,
+                                                   AdwColorScheme   scheme);
+
+ADW_AVAILABLE_IN_ALL
+gboolean adw_style_manager_get_dark          (AdwStyleManager *self);
+ADW_AVAILABLE_IN_ALL
+gboolean adw_style_manager_get_high_contrast (AdwStyleManager *self);
+
+G_END_DECLS
diff --git a/src/adwaita.h b/src/adwaita.h
index 9879d538..ce297888 100644
--- a/src/adwaita.h
+++ b/src/adwaita.h
@@ -50,6 +50,7 @@ G_BEGIN_DECLS
 #include "adw-preferences-window.h"
 #include "adw-squeezer.h"
 #include "adw-status-page.h"
+#include "adw-style-manager.h"
 #include "adw-swipe-tracker.h"
 #include "adw-swipeable.h"
 #include "adw-tab-bar.h"
diff --git a/src/meson.build b/src/meson.build
index 3f26e2f3..6ab3c920 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -15,6 +15,7 @@ adw_public_enum_headers = [
   'adw-header-bar.h',
   'adw-leaflet.h',
   'adw-navigation-direction.h',
+  'adw-style-manager.h',
   'adw-squeezer.h',
   'adw-tab-bar.h',
   'adw-view-switcher.h',
@@ -156,6 +157,7 @@ src_sources = [
   'adw-settings.c',
   'adw-shadow-helper.c',
   'adw-squeezer.c',
+  'adw-style-manager.c',
   'adw-status-page.c',
   'adw-swipe-tracker.c',
   'adw-swipeable.c',