[gimp] Add GimpTreeHandler, a signal connection helper for object trees

[Michael Natterer <mitch src gnome org>]

commit aaab0d40a9214e329ab8aa10aa7708aec92b8a2c
Author: Michael Natterer <mitch gimp org>
Date:   Tue Aug 4 20:12:34 2009 +0200

    Add GimpTreeHandler, a signal connection helper for object trees
    
    A tree-enabled replacement for gimp_container_add,remove_handler(),
    slightly more sane to a degree that makes me think it could replace
    GimpContainer's own handler stuff. Public API consists of two
    function:
    
    - gimp_tree_handler_connect() which connects recursively to a specific
      signal of all items in a container tree.
    
    - gimp_tree_handler_disconnect() is just a wrapper around unrefing the
      handler, but makes sure that dispose() is really executed (which
      actually disconnects things).

 app/core/Makefile.am       |    2 +
 app/core/core-types.h      |    1 +
 app/core/gimptreehandler.c |  240 ++++++++++++++++++++++++++++++++++++++++++++
 app/core/gimptreehandler.h |   64 ++++++++++++
 4 files changed, 307 insertions(+), 0 deletions(-)
---
diff --git a/app/core/Makefile.am b/app/core/Makefile.am
index 5d792e9..ff31b8c 100644
--- a/app/core/Makefile.am
+++ b/app/core/Makefile.am
@@ -346,6 +346,8 @@ libappcore_a_sources = \
 	gimptooloptions.h			\
 	gimptoolpresets.c			\
 	gimptoolpresets.h			\
+	gimptreehandler.c			\
+	gimptreehandler.h			\
 	gimpunit.c				\
 	gimpunit.h				\
 	gimpundo.c				\
diff --git a/app/core/core-types.h b/app/core/core-types.h
index dce9853..5014f28 100644
--- a/app/core/core-types.h
+++ b/app/core/core-types.h
@@ -151,6 +151,7 @@ typedef struct _GimpPdbProgress     GimpPdbProgress;
 typedef struct _GimpProjection      GimpProjection;
 typedef struct _GimpSubProgress     GimpSubProgress;
 typedef struct _GimpTag             GimpTag;
+typedef struct _GimpTreeHandler     GimpTreeHandler;
 
 
 /*  interfaces  */
diff --git a/app/core/gimptreehandler.c b/app/core/gimptreehandler.c
new file mode 100644
index 0000000..1e41b35
--- /dev/null
+++ b/app/core/gimptreehandler.c
@@ -0,0 +1,240 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * GimpTreeHandler
+ * Copyright (C) 2009  Michael Natterer <mitch gimp org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <gegl.h>
+
+#include "core-types.h"
+
+#include "gimpcontainer.h"
+#include "gimptreehandler.h"
+#include "gimpviewable.h"
+
+
+static void   gimp_tree_handler_dispose          (GObject         *object);
+
+static void   gimp_tree_handler_freeze           (GimpTreeHandler *handler,
+                                                  GimpContainer   *container);
+static void   gimp_tree_handler_thaw             (GimpTreeHandler *handler,
+                                                  GimpContainer   *container);
+
+static void   gimp_tree_handler_add_container    (GimpTreeHandler *handler,
+                                                  GimpContainer   *container);
+static void   gimp_tree_handler_add_foreach      (GimpViewable    *viewable,
+                                                  GimpTreeHandler *handler);
+static void   gimp_tree_handler_add              (GimpTreeHandler *handler,
+                                                  GimpViewable    *viewable,
+                                                  GimpContainer   *container);
+
+static void   gimp_tree_handler_remove_container (GimpTreeHandler *handler,
+                                                  GimpContainer   *container);
+static void   gimp_tree_handler_remove_foreach   (GimpViewable    *viewable,
+                                                  GimpTreeHandler *handler);
+static void   gimp_tree_handler_remove           (GimpTreeHandler *handler,
+                                                  GimpViewable    *viewable,
+                                                  GimpContainer   *container);
+
+
+G_DEFINE_TYPE (GimpTreeHandler, gimp_tree_handler, GIMP_TYPE_OBJECT)
+
+#define parent_class gimp_tree_handler_parent_class
+
+
+static void
+gimp_tree_handler_class_init (GimpTreeHandlerClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->dispose = gimp_tree_handler_dispose;
+}
+
+static void
+gimp_tree_handler_init (GimpTreeHandler *handler)
+{
+}
+
+static void
+gimp_tree_handler_dispose (GObject *object)
+{
+  GimpTreeHandler *handler = GIMP_TREE_HANDLER (object);
+
+  if (handler->container)
+    {
+      g_signal_handlers_disconnect_by_func (handler->container,
+                                            gimp_tree_handler_freeze,
+                                            handler);
+      g_signal_handlers_disconnect_by_func (handler->container,
+                                            gimp_tree_handler_thaw,
+                                            handler);
+
+      if (! gimp_container_frozen (handler->container))
+        gimp_tree_handler_remove_container (handler, handler->container);
+
+      g_object_unref (handler->container);
+      handler->container = NULL;
+
+      g_free (handler->signal_name);
+      handler->signal_name = NULL;
+    }
+
+  G_OBJECT_CLASS (parent_class)->dispose (object);
+}
+
+
+/*  public functions  */
+
+GimpTreeHandler *
+gimp_tree_handler_connect (GimpContainer *container,
+                           const gchar   *signal_name,
+                           GCallback      callback,
+                           gpointer       user_data)
+{
+  GimpTreeHandler *handler;
+
+  g_return_val_if_fail (GIMP_IS_CONTAINER (container), NULL);
+  g_return_val_if_fail (signal_name != NULL, NULL);
+
+  handler = g_object_new (GIMP_TYPE_TREE_HANDLER, NULL);
+
+  handler->container   = g_object_ref (container);
+  handler->signal_name = g_strdup (signal_name);
+  handler->callback    = callback;
+  handler->user_data   = user_data;
+
+  if (! gimp_container_frozen (container))
+    gimp_tree_handler_add_container (handler, container);
+
+  g_signal_connect_object (container, "freeze",
+                           G_CALLBACK (gimp_tree_handler_freeze),
+                           handler,
+                           G_CONNECT_SWAPPED);
+  g_signal_connect_object (container, "thaw",
+                           G_CALLBACK (gimp_tree_handler_thaw),
+                           handler,
+                           G_CONNECT_SWAPPED);
+
+  return handler;
+}
+
+void
+gimp_tree_handler_disconnect (GimpTreeHandler *handler)
+{
+  g_return_if_fail (GIMP_IS_TREE_HANDLER (handler));
+
+  g_object_run_dispose (G_OBJECT (handler));
+  g_object_unref (handler);
+}
+
+
+/*  private functions  */
+
+static void
+gimp_tree_handler_freeze (GimpTreeHandler *handler,
+                          GimpContainer   *container)
+{
+  gimp_tree_handler_remove_container (handler, container);
+}
+
+static void
+gimp_tree_handler_thaw (GimpTreeHandler *handler,
+                        GimpContainer   *container)
+{
+  gimp_tree_handler_add_container (handler, container);
+}
+
+static void
+gimp_tree_handler_add_container (GimpTreeHandler *handler,
+                                 GimpContainer   *container)
+{
+  gimp_container_foreach (container,
+                          (GFunc) gimp_tree_handler_add_foreach,
+                          handler);
+
+  g_signal_connect_object (container, "add",
+                           G_CALLBACK (gimp_tree_handler_add),
+                           handler,
+                           G_CONNECT_SWAPPED);
+  g_signal_connect_object (container, "remove",
+                           G_CALLBACK (gimp_tree_handler_remove),
+                           handler,
+                           G_CONNECT_SWAPPED);
+}
+
+static void
+gimp_tree_handler_add_foreach (GimpViewable    *viewable,
+                               GimpTreeHandler *handler)
+{
+  gimp_tree_handler_add (handler, viewable, NULL);
+}
+
+static void
+gimp_tree_handler_add (GimpTreeHandler *handler,
+                       GimpViewable    *viewable,
+                       GimpContainer   *unused)
+{
+  GimpContainer *children = gimp_viewable_get_children (viewable);
+
+  g_signal_connect (viewable,
+                    handler->signal_name,
+                    handler->callback,
+                    handler->user_data);
+
+  if (children)
+    gimp_tree_handler_add_container (handler, children);
+}
+
+static void
+gimp_tree_handler_remove_container (GimpTreeHandler *handler,
+                                    GimpContainer   *container)
+{
+  g_signal_handlers_disconnect_by_func (container,
+                                        gimp_tree_handler_add,
+                                        handler);
+  g_signal_handlers_disconnect_by_func (container,
+                                        gimp_tree_handler_remove,
+                                        handler);
+
+  gimp_container_foreach (container,
+                          (GFunc) gimp_tree_handler_remove_foreach,
+                          handler);
+}
+
+static void
+gimp_tree_handler_remove_foreach (GimpViewable    *viewable,
+                                  GimpTreeHandler *handler)
+{
+  gimp_tree_handler_remove (handler, viewable, NULL);
+}
+
+static void
+gimp_tree_handler_remove (GimpTreeHandler *handler,
+                          GimpViewable    *viewable,
+                          GimpContainer   *unused)
+{
+  GimpContainer *children = gimp_viewable_get_children (viewable);
+
+  if (children)
+    gimp_tree_handler_remove_container (handler, children);
+
+  g_signal_handlers_disconnect_by_func (viewable,
+                                        handler->callback,
+                                        handler->user_data);
+}
diff --git a/app/core/gimptreehandler.h b/app/core/gimptreehandler.h
new file mode 100644
index 0000000..7e6c975
--- /dev/null
+++ b/app/core/gimptreehandler.h
@@ -0,0 +1,64 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * GimpTreeHandler
+ * Copyright (C) 2009  Michael Natterer <mitch gimp org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __GIMP_TREE_HANDLER_H__
+#define __GIMP_TREE_HANDLER_H__
+
+
+#include "core/gimpobject.h"
+
+
+#define GIMP_TYPE_TREE_HANDLER            (gimp_tree_handler_get_type ())
+#define GIMP_TREE_HANDLER(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), GIMP_TYPE_TREE_HANDLER, GimpTreeHandler))
+#define GIMP_TREE_HANDLER_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass), GIMP_TYPE_TREE_HANDLER, GimpTreeHandlerClass))
+#define GIMP_IS_TREE_HANDLER(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GIMP_TYPE_TREE_HANDLER))
+#define GIMP_IS_TREE_HANDLER_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GIMP_TYPE_TREE_HANDLER))
+#define GIMP_TREE_HANDLER_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj), GIMP_TYPE_TREE_HANDLER, GimpTreeHandlerClass))
+
+
+typedef struct _GimpTreeHandlerClass GimpTreeHandlerClass;
+
+struct _GimpTreeHandler
+{
+  GimpObject     parent_instance;
+
+  GimpContainer *container;
+
+  gchar         *signal_name;
+  GCallback      callback;
+  gpointer       user_data;
+};
+
+struct _GimpTreeHandlerClass
+{
+  GimpObjectClass  parent_class;
+};
+
+
+GType             gimp_tree_handler_get_type   (void) G_GNUC_CONST;
+
+GimpTreeHandler * gimp_tree_handler_connect    (GimpContainer   *container,
+                                                const gchar     *signal_name,
+                                                GCallback        callback,
+                                                gpointer         user_data);
+void              gimp_tree_handler_disconnect (GimpTreeHandler *handler);
+
+
+#endif /* __GIMP_TREE_HANDLER_H__ */