[nautilus/antoniof/hide-path-border-on-small-windows: 9/11] container-max-width: Add width-maximized-changed signal

[Carlos Soriano <csoriano src gnome org>]

commit f0eec20acbcf1e52916211ad043618a14cb7424b
Author: António Fernandes <antoniof gnome org>
Date:   Wed Aug 1 21:57:25 2018 +0100

    container-max-width: Add width-maximized-changed signal
    
    It may be useful when we want to change look or behavior depending on
    whether the container has grown to maximum width.
    
    The next commit will make use of this.

 src/nautilus-container-max-width.c | 81 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
---
diff --git a/src/nautilus-container-max-width.c b/src/nautilus-container-max-width.c
index 3ed8c8116..f9352ac22 100644
--- a/src/nautilus-container-max-width.c
+++ b/src/nautilus-container-max-width.c
@@ -6,6 +6,10 @@ struct _NautilusContainerMaxWidth
 {
     GtkBin parent_instance;
     guint max_width;
+
+    gboolean width_maximized;
+    gboolean last_signaled_width_maximized;
+    guint width_maximized_changed_idle_id;
 };
 
 G_DEFINE_TYPE (NautilusContainerMaxWidth, nautilus_container_max_width, GTK_TYPE_BIN)
@@ -17,6 +21,14 @@ enum
     N_PROPS
 };
 
+enum
+{
+    WIDTH_MAXIMIZED_CHANGED,
+    LAST_SIGNAL
+};
+
+static guint signals[LAST_SIGNAL];
+
 void
 nautilus_container_max_width_set_max_width (NautilusContainerMaxWidth *self,
                                             guint                      max_width)
@@ -40,6 +52,13 @@ nautilus_container_max_width_new (void)
 static void
 nautilus_container_max_width_finalize (GObject *object)
 {
+    NautilusContainerMaxWidth *self = NAUTILUS_CONTAINER_MAX_WIDTH (object);
+
+    if (self->width_maximized_changed_idle_id != 0)
+    {
+        g_source_remove (self->width_maximized_changed_idle_id);
+    }
+
     G_OBJECT_CLASS (nautilus_container_max_width_parent_class)->finalize (object);
 }
 
@@ -177,6 +196,49 @@ get_preferred_width_for_height (GtkWidget *widget,
     get_preferred_width (widget, minimum_size, natural_size);
 }
 
+static gboolean
+width_maximized_changed_idle_callback (gpointer userdata)
+{
+    NautilusContainerMaxWidth *self = userdata;
+
+    self->width_maximized_changed_idle_id = 0;
+
+    if (self->width_maximized != self->last_signaled_width_maximized)
+    {
+        g_signal_emit_by_name (self,
+                               "width-maximized-changed",
+                               self->width_maximized);
+        self->last_signaled_width_maximized = self->width_maximized;
+    }
+
+    return G_SOURCE_REMOVE;
+}
+
+static void
+on_size_allocate (GtkWidget    *widget,
+                  GdkRectangle *allocation,
+                  gpointer      userdata)
+{
+    NautilusContainerMaxWidth *self = NAUTILUS_CONTAINER_MAX_WIDTH (widget);
+    gboolean is_width_maximized;
+
+    is_width_maximized = self->max_width == -1 ? FALSE : allocation->width >= self->max_width;
+
+    if (self->width_maximized != is_width_maximized)
+    {
+        self->width_maximized = is_width_maximized;
+
+        /* We want to emit the "width-maximized-changed" signal, but it their
+         * users may trigger a reallocation, which shouldn't happen at this
+         * point because we are still in size_allocate phase. Instead, emit it
+         * on idle*/
+        if (self->width_maximized_changed_idle_id == 0)
+        {
+            self->width_maximized_changed_idle_id = g_idle_add (width_maximized_changed_idle_callback, self);
+        }
+    }
+}
+
 static void
 constructed (GObject *obj)
 {
@@ -187,6 +249,14 @@ constructed (GObject *obj)
     /* We want our parent to gives our preferred width */
     gtk_widget_set_halign (GTK_WIDGET (self), GTK_ALIGN_CENTER);
     self->max_width = -1;
+
+    /* We may want to change the child theming when at max width */
+    self->width_maximized = FALSE;
+    self->last_signaled_width_maximized = FALSE;
+    g_signal_connect (GTK_WIDGET (self),
+                      "size-allocate",
+                      G_CALLBACK (on_size_allocate),
+                      NULL);
 }
 
 static void
@@ -215,6 +285,17 @@ nautilus_container_max_width_class_init (NautilusContainerMaxWidthClass *klass)
                                                        G_MAXINT,
                                                        0,
                                                        G_PARAM_READWRITE));
+
+    signals[WIDTH_MAXIMIZED_CHANGED] = g_signal_new ("width-maximized-changed",
+                                                     NAUTILUS_TYPE_CONTAINER_MAX_WIDTH,
+                                                     G_SIGNAL_RUN_LAST,
+                                                     0,
+                                                     NULL,
+                                                     NULL,
+                                                     g_cclosure_marshal_VOID__BOOLEAN,
+                                                     G_TYPE_NONE,
+                                                     1,
+                                                     G_TYPE_BOOLEAN);
 }
 
 static void