[gtk+] css: Add a -gtk-icon-theme CSS property

[Benjamin Otte <otte src gnome org>]

commit 11d70f1ac30dd491d9d8dac9b9e2c31cee073cc9
Author: Benjamin Otte <otte redhat com>
Date:   Tue Jan 27 00:25:05 2015 +0100

    css: Add a -gtk-icon-theme CSS property
    
    The property is useless to set (it only allows 'initial', 'inherit' and
    'unset' as values), but it is used to track changes to the icon theme.
    And as such, it can ensure that widgets can track when they need to
    reload icons.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=743341

 gtk/Makefile.am                   |    2 +
 gtk/gtkcssiconthemevalue.c        |  135 +++++++++++++++++++++++++++++++++++++
 gtk/gtkcssiconthemevalueprivate.h |   32 +++++++++
 gtk/gtkcssstylepropertyimpl.c     |   19 +++++
 gtk/gtkcsstypesprivate.h          |    1 +
 5 files changed, 189 insertions(+), 0 deletions(-)
---
diff --git a/gtk/Makefile.am b/gtk/Makefile.am
index d44a4dc..2daf367 100644
--- a/gtk/Makefile.am
+++ b/gtk/Makefile.am
@@ -377,6 +377,7 @@ gtk_private_h_sources =             \
        gtkcsseasevalueprivate.h        \
        gtkcssenginevalueprivate.h      \
        gtkcssenumvalueprivate.h        \
+       gtkcssiconthemevalueprivate.h   \
        gtkcssimagebuiltinprivate.h     \
        gtkcssimagecrossfadeprivate.h   \
        gtkcssimagegradientprivate.h    \
@@ -605,6 +606,7 @@ gtk_base_c_sources =                \
        gtkcsseasevalue.c       \
        gtkcssenumvalue.c       \
        gtkcssenginevalue.c     \
+       gtkcssiconthemevalue.c  \
        gtkcssimage.c           \
        gtkcssimagebuiltin.c    \
        gtkcssimagecrossfade.c  \
diff --git a/gtk/gtkcssiconthemevalue.c b/gtk/gtkcssiconthemevalue.c
new file mode 100644
index 0000000..8422f2c
--- /dev/null
+++ b/gtk/gtkcssiconthemevalue.c
@@ -0,0 +1,135 @@
+/* GTK - The GIMP Toolkit
+ * Copyright (C) 2011 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include "gtkcssiconthemevalueprivate.h"
+
+#include "gtkicontheme.h"
+#include "gtksettingsprivate.h"
+#include "gtkstyleproviderprivate.h"
+
+/*
+ * The idea behind this value (and the '-gtk-icon-theme' CSS property) is
+ * to track changes to the icon theme.
+ *
+ * We create a new instance of this value whenever the icon theme changes
+ * (via emitting the changed signal). So as long as the icon theme does
+ * not change, we will compute the same value. We can then compare values
+ * by pointer to see if the icon theme changed.
+ */
+
+struct _GtkCssValue {
+  GTK_CSS_VALUE_BASE
+  GtkIconTheme *icontheme;
+  guint changed_id;
+};
+
+static void
+gtk_css_value_icon_theme_disconnect_handler (GtkCssValue *value)
+{
+  if (value->changed_id == 0)
+    return;
+
+  g_object_set_data (G_OBJECT (value->icontheme), "-gtk-css-value", NULL);
+
+  g_signal_handler_disconnect (value->icontheme, value->changed_id);
+  value->changed_id = 0;
+}
+
+static void
+gtk_css_value_icon_theme_changed_cb (GtkIconTheme *icontheme,
+                                     GtkCssValue  *value)
+{
+  gtk_css_value_icon_theme_disconnect_handler (value);
+}
+
+static void
+gtk_css_value_icon_theme_free (GtkCssValue *value)
+{
+  gtk_css_value_icon_theme_disconnect_handler (value);
+
+  if (value->icontheme)
+    g_object_unref (value->icontheme);
+
+  g_slice_free (GtkCssValue, value);
+}
+
+static GtkCssValue *
+gtk_css_value_icon_theme_compute (GtkCssValue             *icon_theme,
+                                  guint                    property_id,
+                                  GtkStyleProviderPrivate *provider,
+                                 int                      scale,
+                                  GtkCssStyle             *style,
+                                  GtkCssStyle             *parent_style,
+                                  GtkCssDependencies      *dependencies)
+{
+  GtkCssValue *result;
+  GtkIconTheme *icontheme;
+
+  icontheme = gtk_icon_theme_get_for_screen (_gtk_settings_get_screen 
(_gtk_style_provider_private_get_settings (provider)));
+
+  result = g_object_get_data (G_OBJECT (icontheme), "-gtk-css-value");
+  if (result)
+    return _gtk_css_value_ref (result);
+
+  result = _gtk_css_icon_theme_value_new ();
+  result->icontheme = g_object_ref (icontheme);
+
+  g_object_set_data (G_OBJECT (icontheme), "-gtk-css-value", result);
+  result->changed_id = g_signal_connect (icontheme, "changed", G_CALLBACK 
(gtk_css_value_icon_theme_changed_cb), result);
+
+  return result;
+}
+
+static gboolean
+gtk_css_value_icon_theme_equal (const GtkCssValue *value1,
+                                const GtkCssValue *value2)
+{
+  return FALSE;
+}
+
+static GtkCssValue *
+gtk_css_value_icon_theme_transition (GtkCssValue *start,
+                                     GtkCssValue *end,
+                                     guint        property_id,
+                                     double       progress)
+{
+  return NULL;
+}
+
+static void
+gtk_css_value_icon_theme_print (const GtkCssValue *icon_theme,
+                                GString           *string)
+{
+  g_string_append (string, "initial");
+}
+
+static const GtkCssValueClass GTK_CSS_VALUE_ICON_THEME = {
+  gtk_css_value_icon_theme_free,
+  gtk_css_value_icon_theme_compute,
+  gtk_css_value_icon_theme_equal,
+  gtk_css_value_icon_theme_transition,
+  gtk_css_value_icon_theme_print
+};
+
+GtkCssValue *
+_gtk_css_icon_theme_value_new (void)
+{
+  return _gtk_css_value_new (GtkCssValue, &GTK_CSS_VALUE_ICON_THEME);
+}
+
diff --git a/gtk/gtkcssiconthemevalueprivate.h b/gtk/gtkcssiconthemevalueprivate.h
new file mode 100644
index 0000000..6acfdc6
--- /dev/null
+++ b/gtk/gtkcssiconthemevalueprivate.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright © 2012 Red Hat Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Alexander Larsson <alexl gnome org>
+ */
+
+#ifndef __GTK_CSS_ICON_THEME_VALUE_PRIVATE_H__
+#define __GTK_CSS_ICON_THEME_VALUE_PRIVATE_H__
+
+#include "gtkcssparserprivate.h"
+#include "gtkcssvalueprivate.h"
+
+G_BEGIN_DECLS
+
+GtkCssValue *   _gtk_css_icon_theme_value_new           (void);
+
+G_END_DECLS
+
+#endif /* __GTK_CSS_ICON_THEME_VALUE_PRIVATE_H__ */
diff --git a/gtk/gtkcssstylepropertyimpl.c b/gtk/gtkcssstylepropertyimpl.c
index bc40a06..9f6b481 100644
--- a/gtk/gtkcssstylepropertyimpl.c
+++ b/gtk/gtkcssstylepropertyimpl.c
@@ -45,6 +45,7 @@
 #include "gtkcsscornervalueprivate.h"
 #include "gtkcsseasevalueprivate.h"
 #include "gtkcssenginevalueprivate.h"
+#include "gtkcssiconthemevalueprivate.h"
 #include "gtkcssimageprivate.h"
 #include "gtkcssimagebuiltinprivate.h"
 #include "gtkcssimagegradientprivate.h"
@@ -945,6 +946,15 @@ background_position_parse (GtkCssStyleProperty *property,
   return _gtk_css_array_value_parse (parser, _gtk_css_position_value_parse);
 }
 
+static GtkCssValue *
+icon_theme_value_parse (GtkCssStyleProperty *property,
+                       GtkCssParser        *parser)
+{
+  _gtk_css_parser_error (parser, "Only 'inherit', 'initial' or 'unset' are allowed");
+
+  return NULL;
+}
+
 /*** REGISTRATION ***/
 
 void
@@ -975,6 +985,15 @@ _gtk_css_style_property_init_properties (void)
 
   /* properties that aren't referenced when computing values
    * start here */
+  gtk_css_style_property_register        ("-gtk-icon-theme",
+                                          GTK_CSS_PROPERTY_ICON_THEME,
+                                          G_TYPE_NONE,
+                                          GTK_STYLE_PROPERTY_INHERIT,
+                                          GTK_CSS_AFFECTS_ICON,
+                                          icon_theme_value_parse,
+                                          NULL,
+                                          NULL,
+                                          _gtk_css_icon_theme_value_new());
   gtk_css_style_property_register        ("background-color",
                                           GTK_CSS_PROPERTY_BACKGROUND_COLOR,
                                           GDK_TYPE_RGBA,
diff --git a/gtk/gtkcsstypesprivate.h b/gtk/gtkcsstypesprivate.h
index 88bc6f6..b586623 100644
--- a/gtk/gtkcsstypesprivate.h
+++ b/gtk/gtkcsstypesprivate.h
@@ -111,6 +111,7 @@ typedef enum /*< skip >*/ {
 enum { /*< skip >*/
   GTK_CSS_PROPERTY_COLOR,
   GTK_CSS_PROPERTY_FONT_SIZE,
+  GTK_CSS_PROPERTY_ICON_THEME,
   GTK_CSS_PROPERTY_BACKGROUND_COLOR,
   GTK_CSS_PROPERTY_FONT_FAMILY,
   GTK_CSS_PROPERTY_FONT_STYLE,