[gnome-software/1860-app-page-header-switch-to-mobile-layout-at-narrower-width] gs-shell: Add 'allocation-width' property

[Milan Crha <mcrha src gnome org>]

commit 076b8c3760b3091e38924def7c8531314fa2c0c2
Author: Milan Crha <mcrha redhat com>
Date:   Thu Aug 18 11:24:42 2022 +0200

    gs-shell: Add 'allocation-width' property
    
    It can be used, possibly in combination with the `is-narrow` property, to
    determine when the page layout should be changed in a more fine-grained way.

 src/gs-shell.c | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)
---
diff --git a/src/gs-shell.c b/src/gs-shell.c
index e4dcceccb..beb76f0e9 100644
--- a/src/gs-shell.c
+++ b/src/gs-shell.c
@@ -110,6 +110,7 @@ struct _GsShell
 
        gboolean                 activate_after_setup;
        gboolean                 is_narrow;
+       gint                     allocation_width;
        guint                    allocation_changed_cb_id;
 
        GsPage                  *pages[GS_SHELL_MODE_LAST];
@@ -119,6 +120,7 @@ G_DEFINE_TYPE (GsShell, gs_shell, ADW_TYPE_APPLICATION_WINDOW)
 
 typedef enum {
        PROP_IS_NARROW = 1,
+       PROP_ALLOCATION_WIDTH,
 } GsShellProperty;
 
 enum {
@@ -126,7 +128,7 @@ enum {
        SIGNAL_LAST
 };
 
-static GParamSpec *obj_props[PROP_IS_NARROW + 1] = { NULL, };
+static GParamSpec *obj_props[PROP_ALLOCATION_WIDTH + 1] = { NULL, };
 
 static guint signals [SIGNAL_LAST] = { 0 };
 
@@ -2451,6 +2453,12 @@ gs_shell_get_is_narrow (GsShell *shell)
        return shell->is_narrow;
 }
 
+static gint
+gs_shell_get_allocation_width (GsShell *self)
+{
+       return self->allocation_width;
+}
+
 static void
 gs_shell_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
 {
@@ -2460,6 +2468,9 @@ gs_shell_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec
        case PROP_IS_NARROW:
                g_value_set_boolean (value, gs_shell_get_is_narrow (shell));
                break;
+       case PROP_ALLOCATION_WIDTH:
+               g_value_set_int (value, gs_shell_get_allocation_width (shell));
+               break;
        default:
                G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
                break;
@@ -2471,6 +2482,7 @@ gs_shell_set_property (GObject *object, guint prop_id, const GValue *value, GPar
 {
        switch ((GsShellProperty) prop_id) {
        case PROP_IS_NARROW:
+       case PROP_ALLOCATION_WIDTH:
                /* Read only. */
                g_assert_not_reached ();
                break;
@@ -2536,6 +2548,11 @@ allocation_changed_cb (gpointer user_data)
                g_object_notify_by_pspec (G_OBJECT (shell), obj_props[PROP_IS_NARROW]);
        }
 
+       if (shell->allocation_width != allocation.width) {
+               shell->allocation_width = allocation.width;
+               g_object_notify_by_pspec (G_OBJECT (shell), obj_props[PROP_ALLOCATION_WIDTH]);
+       }
+
        shell->allocation_changed_cb_id = 0;
 
        context = gtk_widget_get_style_context (GTK_WIDGET (shell));
@@ -2595,6 +2612,21 @@ gs_shell_class_init (GsShellClass *klass)
                                      FALSE,
                                      G_PARAM_READABLE | G_PARAM_STATIC_STRINGS | G_PARAM_EXPLICIT_NOTIFY);
 
+       /**
+        * GsShell:allocation-width:
+        *
+        * The last allocation width for the window.
+        *
+        * The pages can track this property, possibly in combination with the #GsShell:is-narrow,
+        * to adapt its content to the available width.
+        *
+        * Since: 43
+        */
+       obj_props[PROP_ALLOCATION_WIDTH] =
+               g_param_spec_int ("allocation-width", NULL, NULL,
+                                 G_MININT, G_MAXINT, 0,
+                                 G_PARAM_READABLE | G_PARAM_STATIC_STRINGS | G_PARAM_EXPLICIT_NOTIFY);
+
        g_object_class_install_properties (object_class, G_N_ELEMENTS (obj_props), obj_props);
 
        signals [SIGNAL_LOADED] =