* Add basic (untested) code for handling undo/redo in gMathView

6 files changed, 330 insertions, 16 deletions

diff --git a/gmathview/CMakeLists.txt b/gmathview/CMakeLists.txt
index 5501def..9b8737f 100644
--- a/gmathview/CMakeLists.txt
+++ b/gmathview/CMakeLists.txt
@@ -9,7 +9,11 @@ link_directories (
     ${GTK_LINK_DIRS}
 )
 
-add_library (gmathview SHARED gmathview.c gmathview_utils.c)
+add_library (
+    gmathview SHARED gmathview.c
+                     gmathview_mod_stack.c
+                     gmathview_utils.c
+)
 target_link_libraries (
     gmathview ${GLIB_LIBRARIES} ${GTK_LIBRARIES} gmathcairo
 )
diff --git a/gmathview/gmathview.c b/gmathview/gmathview.c
index 84375cf..ccea3a5 100644
--- a/gmathview/gmathview.c
+++ b/gmathview/gmathview.c
@@ -26,11 +26,28 @@
 
 #include <gmathview.h>
 #include "gmathview_internal.h"
+#include "gmathview_mod_stack.h"
 #include <gdk/gdkkeysyms.h>
 
 G_DEFINE_TYPE (GMathView, g_math_view, GTK_TYPE_DRAWING_AREA)
 
 static void
+g_math_view_force_redraw (GMathView *mathview);
+
+static gboolean
+g_math_view_do_expose (GtkWidget *widget, GdkEventExpose *event);
+
+static gboolean
+g_math_view_do_destroy (GtkWidget *widget, GdkEventAny *event);
+
+static gboolean
+g_math_view_on_key_press (GtkWidget *widget, GdkEventKey *event);
+
+static gboolean
+g_math_view_on_button_press (GtkWidget *widget, GdkEventButton *event);
+
+
+static void
 g_math_view_class_init (GMathViewClass *class)
 {
     GObjectClass    *object_class;
@@ -63,6 +80,8 @@ g_math_view_init (GMathView *mathview)
     priv->current_boxed = NULL;
     priv->selection_type = GMathSelectionNone;
 
+    priv->mod_stack = NULL;
+
     gtk_widget_add_events (GTK_WIDGET (mathview),
                            GDK_BUTTON_PRESS_MASK | GDK_KEY_PRESS_MASK);
 
diff --git a/gmathview/gmathview_internal.h b/gmathview/gmathview_internal.h
index 0788fb8..054a5db 100644
--- a/gmathview/gmathview_internal.h
+++ b/gmathview/gmathview_internal.h
@@ -43,21 +43,8 @@ struct _GMathViewPrivate
 
     GMathBoxed          *current_boxed;
     GMathSelectionType  selection_type;
-};
-
-static void
-g_math_view_force_redraw (GMathView *mathview);
-
-static gboolean
-g_math_view_do_expose (GtkWidget *widget, GdkEventExpose *event);
 
-static gboolean
-g_math_view_do_destroy (GtkWidget *widget, GdkEventAny *event);
-
-static gboolean
-g_math_view_on_key_press (GtkWidget *widget, GdkEventKey *event);
-
-static gboolean
-g_math_view_on_button_press (GtkWidget *widget, GdkEventButton *event);
+    GList               *mod_stack;
+};
 
 #endif
diff --git a/gmathview/gmathview_mod_stack.c b/gmathview/gmathview_mod_stack.c
new file mode 100644
index 0000000..31e5091
--- /dev/null
+++ b/gmathview/gmathview_mod_stack.c
@@ -0,0 +1,211 @@
+/*
+ * gMathView, mathematic expressions viewing & editing widget
+ *
+ *  # Modification stack source
+ *
+ * Author : Guillaume Seguin
+ * Email : guillaume@segu.in
+ *
+ * Copyright (c) 2007 Guillaume Seguin <guillaume@segu.in>
+ *
+ * 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 2
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA  02110-1301, USA.
+ */
+
+#include <gmathview.h>
+#include "gmathview_internal.h"
+#include "gmathview_mod_stack.h"
+
+static GMathMod*
+gmathmod_new (GMathModType type);
+
+static void
+g_math_view_push_to_mod_stack (GMathView *mathview, GMathMod *mod);
+
+static void
+g_math_view_destroy_mod_stack (GList *stack);
+
+void
+g_math_view_undo (GMathView *mathview)
+{
+    GMathViewPrivate *priv;
+    GMathMod         *mod;
+
+    priv = G_MATH_VIEW_GET_PRIVATE (mathview);
+
+    if (!priv->mod_stack || !priv->mod_stack->data)
+        return;
+
+    mod = (GMathMod *) priv->mod_stack->data;
+
+    switch (mod->type)
+    {
+        case GMathModUpdateParent:
+            ((GMathSymbol *) mod->data1)->parent = mod->data2;
+            break;
+        case GMathModUpdateValue:
+            ((GMathSymbol *) mod->data1)->value = mod->data2;
+            break;
+        case GMathModUpdateRoot:
+            priv->formula->root = ((GMathSymbol *) mod->data1);
+            break;
+    }
+
+    priv->mod_stack = priv->mod_stack->next;
+}
+
+void
+g_math_view_redo (GMathView *mathview)
+{
+    GMathViewPrivate *priv;
+    GMathMod         *mod;
+
+    priv = G_MATH_VIEW_GET_PRIVATE (mathview);
+
+    if (!priv->mod_stack || !priv->mod_stack->prev)
+        return;
+
+    mod = (GMathMod *) priv->mod_stack->prev->data;
+
+    if (!mod)
+        return;
+
+    switch (mod->type)
+    {
+        case GMathModUpdateParent:
+            ((GMathSymbol *) mod->data1)->parent = mod->data3;
+            break;
+        case GMathModUpdateValue:
+            ((GMathSymbol *) mod->data1)->value = mod->data3;
+            break;
+        case GMathModUpdateRoot:
+            priv->formula->root = ((GMathSymbol *) mod->data2);
+            break;
+    }
+
+    priv->mod_stack = priv->mod_stack->prev;
+}
+
+gboolean
+g_math_view_can_undo (GMathView *mathview)
+{
+    GMathViewPrivate *priv;
+
+    priv = G_MATH_VIEW_GET_PRIVATE (mathview);
+
+    return (priv->mod_stack && priv->mod_stack->data);
+}
+
+gboolean
+g_math_view_can_redo (GMathView *mathview)
+{
+    GMathViewPrivate *priv;
+
+    priv = G_MATH_VIEW_GET_PRIVATE (mathview);
+
+    return (priv->mod_stack && priv->mod_stack->prev);
+}
+
+void
+g_math_view_update_parent (GMathView *mathview, GMathSymbol *symbol,
+                           GMathSymbol *new_parent)
+{
+    GMathMod *mod;
+
+    mod = gmathmod_new (GMathModUpdateParent);
+
+    mod->data1 = (gpointer) symbol;
+    mod->data2 = (gpointer) symbol->parent;
+    mod->data3 = (gpointer) new_parent;
+
+    symbol->parent = new_parent;
+
+    g_math_view_push_to_mod_stack (mathview, mod);
+}
+
+void
+g_math_view_update_value (GMathView *mathview, GMathSymbol *symbol,
+                          gpointer new_value)
+{
+    GMathMod *mod;
+
+    mod = gmathmod_new (GMathModUpdateParent);
+
+    mod->data1 = (gpointer) symbol;
+    mod->data2 = (gpointer) symbol->value;
+    mod->data3 = (gpointer) new_value;
+
+    symbol->value = new_value;
+
+    g_math_view_push_to_mod_stack (mathview, mod);
+}
+
+void
+g_math_view_update_root (GMathView *mathview, GMathSymbol *new_root)
+{
+    GMathMod *mod;
+    GMathViewPrivate *priv;
+
+    priv = G_MATH_VIEW_GET_PRIVATE (mathview);
+    mod = gmathmod_new (GMathModUpdateRoot);
+
+    mod->data1 = (gpointer) priv->formula->root;
+    mod->data2 = (gpointer) new_root;
+
+    priv->formula->root = new_root;
+
+    g_math_view_push_to_mod_stack (mathview, mod);
+}
+
+static GMathMod*
+gmathmod_new (GMathModType type)
+{
+    GMathMod *mod = g_new0 (GMathMod, 1);
+    mod->type = type;
+    return mod;
+}
+
+static void
+g_math_view_push_to_mod_stack (GMathView *mathview, GMathMod *mod)
+{
+    GMathViewPrivate *priv;
+    GList            *stack;
+
+    priv = G_MATH_VIEW_GET_PRIVATE (mathview);
+
+    if (!priv->mod_stack || !priv->mod_stack->prev)
+    {
+        priv->mod_stack = g_list_prepend (priv->mod_stack, mod);
+        return;
+    }
+
+    stack = priv->mod_stack->prev;
+    priv->mod_stack->prev = NULL;
+    stack->next = NULL;
+    priv->mod_stack = g_list_prepend (priv->mod_stack, mod);
+
+    g_math_view_destroy_mod_stack (g_list_first (stack));
+}
+
+static void
+g_math_view_destroy_mod_stack (GList *stack)
+{
+    if (!stack)
+        return;
+
+    stack = g_list_remove (stack, stack->data);
+
+    g_math_view_destroy_mod_stack (stack);
+}
diff --git a/gmathview/gmathview_mod_stack.h b/gmathview/gmathview_mod_stack.h
new file mode 100644
index 0000000..7871260
--- /dev/null
+++ b/gmathview/gmathview_mod_stack.h
@@ -0,0 +1,68 @@
+/*
+ * gMathView, mathematic expressions viewing & editing widget
+ *
+ *  # Modifications stack header
+ *
+ * Author : Guillaume Seguin
+ * Email : guillaume@segu.in
+ *
+ * Copyright (c) 2007 Guillaume Seguin <guillaume@segu.in>
+ *
+ * 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 2
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA  02110-1301, USA.
+ */
+
+#ifndef _GMATHVIEW_MODSTACK_H
+#define _GMATHVIEW_MODSTACK_H
+
+#include <gmathview.h>
+
+typedef struct _GMathMod GMathMod;
+
+typedef enum
+{
+    GMathModUpdateParent,
+    GMathModUpdateValue,
+    GMathModUpdateRoot,
+} GMathModType;
+
+struct _GMathMod
+{
+    GMathModType        type;
+    gpointer            data1;
+    gpointer            data2;
+    gpointer            data3;
+};
+
+/*
+ * Meaning of data* pointers for each modification type:
+ *
+ * UpdateParent:
+ *  o data1: symbol
+ *  o data2: old parent
+ *  o data3: new parent
+ * 
+ * UpdateParent:
+ *  o data1: symbol
+ *  o data2: old value
+ *  o data3: new value
+ *
+ * UpdateRoot:
+ *  o data1: old root
+ *  o data2: new root
+ *  o data3: none
+ */
+
+#endif
diff --git a/include/gmathview.h b/include/gmathview.h
index 03ec875..ca9c59a 100644
--- a/include/gmathview.h
+++ b/include/gmathview.h
@@ -88,12 +88,37 @@ g_math_view_get_formula (GMathView *mathview);
 void
 g_math_view_set_formula (GMathView *mathview, GMathFormula *formula);
 
+/* Editor methods */
+
 gboolean
 g_math_view_get_editor_mode (GMathView *mathview);
 
 void
 g_math_view_set_editor_mode (GMathView *mathview, gboolean editor_mode);
 
+void
+g_math_view_undo (GMathView *mathview);
+
+void
+g_math_view_redo (GMathView *mathview);
+
+gboolean
+g_math_view_can_undo (GMathView *mathview);
+
+gboolean
+g_math_view_can_redo (GMathView *mathview);
+
+void
+g_math_view_update_parent (GMathView *mathview, GMathSymbol *symbol,
+                           GMathSymbol *new_parent);
+
+void
+g_math_view_update_value (GMathView *mathview, GMathSymbol *symbol,
+                          gpointer new_value);
+
+void
+g_math_view_update_root (GMathView *mathview, GMathSymbol *new_root);
+
 G_END_DECLS
 
 /* Helper functions */