[gnome-shell] Add ShellGenericContainer, which makes it possible to write containers in JS

[Colin Walters <walters src gnome org>]

commit 91353c6d603bfcc05f7ebeeb52b8916deb955774
Author: Colin Walters <walters verbum org>
Date:   Tue Aug 4 16:08:59 2009 -0400

    Add ShellGenericContainer, which makes it possible to write containers in JS
    
    Subclass ClutterGroup (to avoid having to implement all of dispose,
    raise, lower, add, etc.), and have it proxy the allocation requests
    out into signals.  We have to group up the two out parameters
    into a struct unfortunately.
    
    Included example code in the C file source for now.

 src/Makefile.am               |    2 +
 src/shell-generic-container.c |  240 +++++++++++++++++++++++++++++++++++++++++
 src/shell-generic-container.h |   44 ++++++++
 3 files changed, 286 insertions(+), 0 deletions(-)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index c9ad0d9..1959d09 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -66,6 +66,8 @@ libgnome_shell_la_SOURCES =			\
 	shell-embedded-window-private.h		\
 	shell-gconf.c				\
 	shell-gconf.h				\
+	shell-generic-container.c           \
+	shell-generic-container.h           \
 	shell-gtk-embed.c			\
 	shell-gtk-embed.h			\
 	shell-overflow-list.c		\
diff --git a/src/shell-generic-container.c b/src/shell-generic-container.c
new file mode 100644
index 0000000..db74ecb
--- /dev/null
+++ b/src/shell-generic-container.c
@@ -0,0 +1,240 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
+
+/**
+ * SECTION:shell-generic-container
+ * @short_description: A container class with signals for allocation
+ *
+ * #ShellGenericContainer is mainly a workaround for the current
+ * lack of GObject subclassing + vfunc overrides in gjs.  We
+ * implement the container interface, but proxy the virtual functions
+ * into signals, which gjs can catch.
+ */
+
+/* Example implementation of a horzontal box with PACK_EXPAND for all,
+ vertically and horizontally centering.
+
+function TestFixedBox() {
+    this._init();
+}
+
+TestFixedBox.prototype = {
+    _init : function () {
+        this.actor = new Shell.GenericContainer();
+        this.spacing = 4;
+        this.actor.connect('get-preferred-width', Lang.bind(this, function (actor, for_height, alloc) {
+            let children = this.actor.get_children();
+            let max_child_min = 0;
+            let max_child_nat = 0;
+            for (let i = 0; i < children.length; i++) {
+                let spacing = i > 0 && i < children.length-1 ? this.spacing : 0;
+                let [child_min, child_nat] = children[i].get_preferred_width(for_height);
+                if (child_min > max_child_min)
+                    max_child_min = child_min;
+                if (child_nat > max_child_nat)
+                    max_child_nat = child_nat;
+            }
+            let totalSpacing = this.spacing * Math.abs(children.length - 1);
+            alloc.min_size = children.length * max_child_min + totalSpacing;
+            alloc.nat_size = children.length * max_child_nat + totalSpacing;
+        }));
+        this.actor.connect('get-preferred-height', Lang.bind(this, function (actor, for_width, alloc) {
+            let children = this.actor.get_children();
+            let max_child_min = 0;
+            let max_child_nat = 0;
+            for (let i = 0; i < children.length; i++) {
+                let [child_min, child_nat] = children[i].get_preferred_height(for_width);
+                if (child_min > max_child_min)
+                    max_child_min = child_min;
+                if (child_nat > max_child_nat)
+                    max_child_nat = child_nat;
+            }
+            alloc.min_size = max_child_min;
+            alloc.nat_size = max_child_nat;
+        }));
+        this.actor.connect('allocate', Lang.bind(this, function (actor, box, flags) {
+            let children = this.actor.get_children();
+            let totalSpacing = (this.spacing * Math.abs(children.length - 1));
+            let child_width = (box.x2 - box.x1 - totalSpacing) / (children.length);
+            let child_height = box.y2 - box.y1;
+
+            let x = box.x1;
+            for (let i = 0; i < children.length; i++) {
+                let [child_min, child_nat] = children[i].get_preferred_height(child_width);
+                let vSpacing = Math.abs(child_height - child_nat) / 2;
+                let childBox = new Clutter.ActorBox();
+                childBox.x1 = x;
+                childBox.y1 = vSpacing;
+                childBox.x2 = x+child_width;
+                childBox.y2 = child_height - vSpacing;
+                children[i].allocate(childBox, flags);
+                x += this.spacing + child_width;
+            }
+        }));
+    }
+}
+
+function runTestFixedBox() {
+    let testBox = new TestFixedBox();
+    let c = new Clutter.Color();
+    c.from_pixel(0xff0000a0);
+    let r = new Clutter.Rectangle({ width: 50, height: 100, color: c });
+    testBox.actor.add_actor(r);
+    r = new Clutter.Rectangle({ width: 90, height: 70, color: c });
+    testBox.actor.add_actor(r);
+    r = new Clutter.Rectangle({ width: 90, height: 70, color: c });
+    testBox.actor.add_actor(r);
+    r = new Clutter.Rectangle({ width: 30, height: 10, color: c });
+    testBox.actor.add_actor(r);
+
+    c.from_pixel(0x00ff00a0);
+    let borderBox = new Big.Box({ border: 1, border_color: c });
+    borderBox.set_position(100, 100);
+    borderBox.append(testBox.actor, Big.BoxPackFlags.NONE);
+    Shell.Global.get().stage.add_actor(borderBox);
+}
+*/
+
+#include "shell-generic-container.h"
+
+#include <clutter/clutter.h>
+#include <gtk/gtk.h>
+#include <girepository.h>
+
+G_DEFINE_TYPE(ShellGenericContainer, shell_generic_container, CLUTTER_TYPE_GROUP);
+
+struct _ShellGenericContainerPrivate {
+  gpointer dummy;
+};
+
+/* Signals */
+enum
+{
+  GET_PREFERRED_WIDTH,
+  GET_PREFERRED_HEIGHT,
+  ALLOCATE,
+  LAST_SIGNAL
+};
+
+static guint shell_generic_container_signals [LAST_SIGNAL] = { 0 };
+
+
+static gpointer
+shell_generic_container_allocation_ref (ShellGenericContainerAllocation *alloc)
+{
+  alloc->_refcount++;
+  return alloc;
+}
+
+static void
+shell_generic_container_allocation_unref (ShellGenericContainerAllocation *alloc)
+{
+  if (--alloc->_refcount == 0)
+    {
+      g_slice_free1 (sizeof (ShellGenericContainerAllocation), alloc);
+    }
+}
+
+static void
+shell_generic_container_allocate (ClutterActor          *self,
+                                  const ClutterActorBox *box,
+                                  ClutterAllocationFlags flags)
+{
+  /* chain up to set actor->allocation */
+  (CLUTTER_ACTOR_CLASS (g_type_class_peek (clutter_actor_get_type ())))->allocate (self, box, flags);
+
+  g_signal_emit (G_OBJECT (self), shell_generic_container_signals[ALLOCATE], 0,
+                 box, flags);
+}
+
+static void
+shell_generic_container_get_preferred_width (ClutterActor *actor,
+                                             gfloat for_height,
+                                             gfloat *min_width_p,
+                                             gfloat *natural_width_p)
+{
+  ShellGenericContainerAllocation *alloc = g_slice_alloc0 (sizeof (ShellGenericContainerAllocation));
+  alloc->_refcount = 1;
+  g_signal_emit (G_OBJECT (actor), shell_generic_container_signals[GET_PREFERRED_WIDTH], 0,
+                 for_height, alloc);
+  if (min_width_p)
+    *min_width_p = alloc->min_size;
+  if (natural_width_p)
+    *natural_width_p = alloc->natural_size;
+  shell_generic_container_allocation_unref (alloc);
+}
+
+static void
+shell_generic_container_get_preferred_height (ClutterActor *actor,
+                                              gfloat for_width,
+                                              gfloat *min_height_p,
+                                              gfloat *natural_height_p)
+{
+  ShellGenericContainerAllocation *alloc = g_slice_alloc0 (sizeof (ShellGenericContainerAllocation));
+  alloc->_refcount = 1;
+  g_signal_emit (G_OBJECT (actor), shell_generic_container_signals[GET_PREFERRED_HEIGHT], 0,
+                 for_width, alloc);
+  if (min_height_p)
+    *min_height_p = alloc->min_size;
+  if (natural_height_p)
+    *natural_height_p = alloc->natural_size;
+  shell_generic_container_allocation_unref (alloc);
+}
+
+static void
+shell_generic_container_class_init (ShellGenericContainerClass *klass)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+  ClutterActorClass *actor_class = CLUTTER_ACTOR_CLASS (klass);
+
+  actor_class->get_preferred_width = shell_generic_container_get_preferred_width;
+  actor_class->get_preferred_height = shell_generic_container_get_preferred_height;
+  actor_class->allocate = shell_generic_container_allocate;
+
+  shell_generic_container_signals[GET_PREFERRED_WIDTH] =
+    g_signal_new ("get-preferred-width",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL,
+                  gi_cclosure_marshal_generic,
+                  G_TYPE_NONE, 2, G_TYPE_FLOAT, SHELL_TYPE_GENERIC_CONTAINER_ALLOCATION);
+
+  shell_generic_container_signals[GET_PREFERRED_HEIGHT] =
+    g_signal_new ("get-preferred-height",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL,
+                  gi_cclosure_marshal_generic,
+                  G_TYPE_NONE, 2, G_TYPE_FLOAT, SHELL_TYPE_GENERIC_CONTAINER_ALLOCATION);
+
+  shell_generic_container_signals[ALLOCATE] =
+    g_signal_new ("allocate",
+                  G_TYPE_FROM_CLASS (klass),
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL,
+                  gi_cclosure_marshal_generic,
+                  G_TYPE_NONE, 2, CLUTTER_TYPE_ACTOR_BOX, CLUTTER_TYPE_ALLOCATION_FLAGS);
+
+  g_type_class_add_private (gobject_class, sizeof (ShellGenericContainerPrivate));
+}
+
+static void
+shell_generic_container_init (ShellGenericContainer *area)
+{
+  area->priv = G_TYPE_INSTANCE_GET_PRIVATE (area, SHELL_TYPE_GENERIC_CONTAINER,
+                                            ShellGenericContainerPrivate);
+}
+
+GType shell_generic_container_allocation_get_type (void)
+{
+  static GType gtype = G_TYPE_INVALID;
+  if (gtype == G_TYPE_INVALID)
+    {
+      gtype = g_boxed_type_register_static ("ShellGenericContainerAllocation",
+         (GBoxedCopyFunc)shell_generic_container_allocation_ref,
+         (GBoxedFreeFunc)shell_generic_container_allocation_unref);
+    }
+  return gtype;
+}
diff --git a/src/shell-generic-container.h b/src/shell-generic-container.h
new file mode 100644
index 0000000..0740a56
--- /dev/null
+++ b/src/shell-generic-container.h
@@ -0,0 +1,44 @@
+#ifndef __SHELL_GENERIC_CONTAINER_H__
+#define __SHELL_GENERIC_CONTAINER_H__
+
+#include <clutter/clutter.h>
+#include <gtk/gtk.h>
+
+#define SHELL_TYPE_GENERIC_CONTAINER                 (shell_generic_container_get_type ())
+#define SHELL_GENERIC_CONTAINER(obj)                 (G_TYPE_CHECK_INSTANCE_CAST ((obj), SHELL_TYPE_GENERIC_CONTAINER, ShellGenericContainer))
+#define SHELL_GENERIC_CONTAINER_CLASS(klass)         (G_TYPE_CHECK_CLASS_CAST ((klass), SHELL_TYPE_GENERIC_CONTAINER, ShellGenericContainerClass))
+#define SHELL_IS_GENERIC_CONTAINER(obj)              (G_TYPE_CHECK_INSTANCE_TYPE ((obj), SHELL_TYPE_GENERIC_CONTAINER))
+#define SHELL_IS_GENERIC_CONTAINER_CLASS(klass)      (G_TYPE_CHECK_CLASS_TYPE ((klass), SHELL_TYPE_GENERIC_CONTAINER))
+#define SHELL_GENERIC_CONTAINER_GET_CLASS(obj)       (G_TYPE_INSTANCE_GET_CLASS ((obj), SHELL_TYPE_GENERIC_CONTAINER, ShellGenericContainerClass))
+
+typedef struct {
+  float min_size;
+  float natural_size;
+
+  /* <private> */
+  guint _refcount;
+} ShellGenericContainerAllocation;
+
+#define SHELL_TYPE_GENERIC_CONTAINER_ALLOCATION (shell_generic_container_allocation_get_type ())
+GType shell_generic_container_allocation_get_type (void);
+
+typedef struct _ShellGenericContainer        ShellGenericContainer;
+typedef struct _ShellGenericContainerClass   ShellGenericContainerClass;
+
+typedef struct _ShellGenericContainerPrivate ShellGenericContainerPrivate;
+
+struct _ShellGenericContainer
+{
+    ClutterGroup parent;
+
+    ShellGenericContainerPrivate *priv;
+};
+
+struct _ShellGenericContainerClass
+{
+    ClutterGroupClass parent_class;
+};
+
+GType shell_generic_container_get_type (void) G_GNUC_CONST;
+
+#endif /* __SHELL_GENERIC_CONTAINER_H__ */