Introduce LdUndoAction.

4 files changed, 207 insertions, 0 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7fa70ac..4c83c36 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -110,6 +110,7 @@ set (project_DOC_DIR "${CMAKE_CURRENT_SOURCE_DIR}/docs/reference")
 set (liblogdiag_SOURCES
 	liblogdiag/ld-marshal.c
 	liblogdiag/ld-types.c
+	liblogdiag/ld-undo-action.c
 	liblogdiag/ld-diagram.c
 	liblogdiag/ld-diagram-object.c
 	liblogdiag/ld-diagram-symbol.c
@@ -125,6 +126,7 @@ set (liblogdiag_HEADERS
 	liblogdiag/liblogdiag.h
 	liblogdiag/ld-marshal.h
 	liblogdiag/ld-types.h
+	liblogdiag/ld-undo-action.h
 	liblogdiag/ld-diagram.h
 	liblogdiag/ld-diagram-object.h
 	liblogdiag/ld-diagram-symbol.h
diff --git a/liblogdiag/ld-undo-action.c b/liblogdiag/ld-undo-action.c
new file mode 100644
index 0000000..924a03e
--- /dev/null
+++ b/liblogdiag/ld-undo-action.c
@@ -0,0 +1,128 @@
+/*
+ * ld-undo-action.c
+ *
+ * This file is a part of logdiag.
+ * Copyright Přemysl Janouch 2011. All rights reserved.
+ *
+ * See the file LICENSE for licensing information.
+ *
+ */
+
+#include <string.h>
+
+#include "liblogdiag.h"
+#include "config.h"
+
+
+/**
+ * SECTION:ld-undo-action
+ * @short_description: An action that can be undone.
+ * @see_also: #LdDiagram, #LdDiagramObject
+ *
+ * #LdUndoAction represents an action that can be reverted.
+ */
+
+/*
+ * LdUndoActionPrivate:
+ * @undo_func: a callback to undo the action.
+ * @redo_func: a callback to redo the action.
+ * @destroy_func: a callback to destroy user data.
+ * @user_data: data given by the user.
+ */
+struct _LdUndoActionPrivate
+{
+	LdUndoActionFunc undo_func;
+	LdUndoActionFunc redo_func;
+	LdUndoActionFunc destroy_func;
+	gpointer user_data;
+};
+
+static void ld_undo_action_finalize (GObject *gobject);
+
+
+G_DEFINE_TYPE (LdUndoAction, ld_undo_action, G_TYPE_OBJECT);
+
+static void
+ld_undo_action_class_init (LdUndoActionClass *klass)
+{
+	GObjectClass *object_class;
+
+	object_class = G_OBJECT_CLASS (klass);
+	object_class->finalize = ld_undo_action_finalize;
+
+	g_type_class_add_private (klass, sizeof (LdUndoActionPrivate));
+}
+
+static void
+ld_undo_action_init (LdUndoAction *self)
+{
+	self->priv = G_TYPE_INSTANCE_GET_PRIVATE
+		(self, LD_TYPE_UNDO_ACTION, LdUndoActionPrivate);
+}
+
+static void
+ld_undo_action_finalize (GObject *gobject)
+{
+	LdUndoAction *self;
+
+	self = LD_UNDO_ACTION (gobject);
+	if (self->priv->destroy_func)
+		self->priv->destroy_func (self->priv->user_data);
+
+	/* Chain up to the parent class. */
+	G_OBJECT_CLASS (ld_undo_action_parent_class)->finalize (gobject);
+}
+
+
+/**
+ * ld_undo_action_new:
+ * @undo_func: a callback to undo the action.
+ * @redo_func: a callback to redo the action.
+ * @destroy_func: (allow-none): a callback to destroy user data.
+ * @user_data: user data passed to callbacks.
+ *
+ * Return value: a new #LdUndoAction object.
+ */
+LdUndoAction *
+ld_undo_action_new (LdUndoActionFunc undo_func,
+	LdUndoActionFunc redo_func, LdUndoActionFunc destroy_func,
+	gpointer user_data)
+{
+	LdUndoAction *self;
+
+	g_return_val_if_fail (undo_func != NULL, NULL);
+	g_return_val_if_fail (redo_func != NULL, NULL);
+
+	self = g_object_new (LD_TYPE_UNDO_ACTION, NULL);
+	self->priv->undo_func = undo_func;
+	self->priv->redo_func = redo_func;
+	self->priv->destroy_func = destroy_func;
+	self->priv->user_data = user_data;
+	return self;
+}
+
+/**
+ * ld_undo_action_undo:
+ * @self: an #LdUndoAction object.
+ *
+ * Undo the action handled by this object.
+ */
+void
+ld_undo_action_undo (LdUndoAction *self)
+{
+	g_return_if_fail (LD_IS_UNDO_ACTION (self));
+	self->priv->undo_func (self->priv->user_data);
+}
+
+/**
+ * ld_undo_action_redo:
+ * @self: an #LdUndoAction object.
+ *
+ * Redo the action handled by this object.
+ */
+void
+ld_undo_action_redo (LdUndoAction *self)
+{
+	g_return_if_fail (LD_IS_UNDO_ACTION (self));
+	self->priv->redo_func (self->priv->user_data);
+}
diff --git a/liblogdiag/ld-undo-action.h b/liblogdiag/ld-undo-action.h
new file mode 100644
index 0000000..141b255
--- /dev/null
+++ b/liblogdiag/ld-undo-action.h
@@ -0,0 +1,76 @@
+/*
+ * ld-undo-action.h
+ *
+ * This file is a part of logdiag.
+ * Copyright Přemysl Janouch 2011. All rights reserved.
+ *
+ * See the file LICENSE for licensing information.
+ *
+ */
+
+#ifndef __LD_UNDO_ACTION_H__
+#define __LD_UNDO_ACTION_H__
+
+G_BEGIN_DECLS
+
+
+#define LD_TYPE_UNDO_ACTION (ld_undo_action_get_type ())
+#define LD_UNDO_ACTION(obj) (G_TYPE_CHECK_INSTANCE_CAST \
+	((obj), LD_TYPE_UNDO_ACTION, LdUndoAction))
+#define LD_UNDO_ACTION_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST \
+	((klass), LD_TYPE_UNDO_ACTION, LdUndoActionClass))
+#define LD_IS_UNDO_ACTION(obj) (G_TYPE_CHECK_INSTANCE_TYPE \
+	((obj), LD_TYPE_UNDO_ACTION))
+#define LD_IS_UNDO_ACTION_CLASS(klass) (G_TYPE_CHECK_INSTANCE_TYPE \
+	((klass), LD_TYPE_UNDO_ACTION))
+#define LD_UNDO_ACTION_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS \
+	((obj), LD_UNDO_ACTION, LdUndoActionClass))
+
+typedef struct _LdUndoAction LdUndoAction;
+typedef struct _LdUndoActionPrivate LdUndoActionPrivate;
+typedef struct _LdUndoActionClass LdUndoActionClass;
+
+
+/**
+ * LdUndoAction:
+ */
+struct _LdUndoAction
+{
+/*< private >*/
+	GObject parent_instance;
+	LdUndoActionPrivate *priv;
+};
+
+/**
+ * LdUndoActionClass:
+ */
+struct _LdUndoActionClass
+{
+/*< private >*/
+	GObjectClass parent_class;
+};
+
+
+/**
+ * LdUndoActionFunc:
+ * @user_data: user data passed to ld_undo_action_new().
+ *
+ * A callback function prototype for actions.
+ */
+typedef void (*LdUndoActionFunc) (gpointer user_data);
+
+
+GType ld_undo_action_get_type (void) G_GNUC_CONST;
+
+/* TODO: Extend the methods (with eg. a string description). */
+LdUndoAction *ld_undo_action_new (LdUndoActionFunc undo_func,
+	LdUndoActionFunc redo_func, LdUndoActionFunc destroy_func,
+	gpointer user_data);
+void ld_undo_action_undo (LdUndoAction *self);
+void ld_undo_action_redo (LdUndoAction *self);
+
+
+G_END_DECLS
+
+#endif /* ! __LD_UNDO_ACTION_H__ */
+
diff --git a/liblogdiag/liblogdiag.h b/liblogdiag/liblogdiag.h
index 61b6149..769662e 100644
--- a/liblogdiag/liblogdiag.h
+++ b/liblogdiag/liblogdiag.h
@@ -21,6 +21,7 @@
 #include "ld-symbol-category.h"
 #include "ld-library.h"
 
+#include "ld-undo-action.h"
 #include "ld-diagram-object.h"
 #include "ld-diagram-symbol.h"
 #include "ld-diagram.h"