Added basic undo support - thanks to ecrire (Tasn) for the undo_redo_do function

ChangeLog

@@ -1,3 +1,7 @@
+2014-05-15  ajwillia.ms (Andy Williams)
+
+    * Add basic undo support
+
 2014-04-27  ajwillia.ms (Andy Williams)
 
 	* Add simple build functions

src/bin/editor/edi_editor.c

@@ -5,7 +5,7 @@
 #include <libgen.h>
 
 #include <Eina.h>
-#include <Eio.h>
+#include <Elementary.h>
 
 #include "edi_editor.h"
 
@@ -14,6 +14,86 @@
 #include "edi_private.h"
 
 
+static void
+_undo_do(Edi_Editor *editor, Elm_Entry_Change_Info *inf)
+{
+   if (inf->insert)
+     {
+        const Evas_Object *tb = elm_entry_textblock_get(editor->entry);
+        Evas_Textblock_Cursor *mcur, *end;
+        mcur = (Evas_Textblock_Cursor *) evas_object_textblock_cursor_get(tb);
+        end = evas_object_textblock_cursor_new(tb);
+
+        if (inf->insert)
+          {
+             elm_entry_cursor_pos_set(editor->entry, inf->change.insert.pos);
+             evas_textblock_cursor_pos_set(end, inf->change.insert.pos +
+                   inf->change.insert.plain_length);
+          }
+        else
+          {
+             elm_entry_cursor_pos_set(editor->entry, inf->change.del.start);
+             evas_textblock_cursor_pos_set(end, inf->change.del.end);
+          }
+
+        evas_textblock_cursor_range_delete(mcur, end);
+        evas_textblock_cursor_free(end);
+        elm_entry_calc_force(editor->entry);
+     }
+   else
+     {
+        if (inf->insert)
+          {
+             elm_entry_cursor_pos_set(editor->entry, inf->change.insert.pos);
+             elm_entry_entry_insert(editor->entry, inf->change.insert.content);
+          }
+        else
+          {
+             size_t start;
+             start = (inf->change.del.start < inf->change.del.end) ?
+                inf->change.del.start : inf->change.del.end;
+
+             elm_entry_cursor_pos_set(editor->entry, start);
+             elm_entry_entry_insert(editor->entry, inf->change.insert.content);
+             elm_entry_cursor_pos_set(editor->entry, inf->change.del.end);
+          }
+     }
+}
+
+static void
+_undo_cb(void *data, Evas_Object *obj EINA_UNUSED, void *event_info EINA_UNUSED)
+{
+   Elm_Entry_Change_Info *change;
+   Edi_Editor *editor = data;
+
+   if (!eina_list_next(editor->undo_stack))
+      return;
+
+   change = eina_list_data_get(editor->undo_stack);
+   _undo_do(editor, change);
+   editor->undo_stack = eina_list_next(editor->undo_stack);
+}
+
+static void
+_changed_cb(void *data, Evas_Object *obj EINA_UNUSED, void *event_info)
+{
+   Elm_Entry_Change_Info *change;
+   Edi_Editor *editor = data;
+
+   change = calloc(1, sizeof(*change));
+   memcpy(change, event_info, sizeof(*change));
+   if (change->insert)
+     {
+        eina_stringshare_ref(change->change.insert.content);
+     }
+   else
+     {
+        eina_stringshare_ref(change->change.del.content);
+     }
+
+   editor->undo_stack = eina_list_prepend(editor->undo_stack, change);
+}
+
 static void
 _smart_cb_key_down(void *data, Evas *e EINA_UNUSED,
                    Evas_Object *obj EINA_UNUSED, void *event)
@@ -43,6 +123,10 @@ _smart_cb_key_down(void *data, Evas *e EINA_UNUSED,
           {
              edi_mainview_search();
           }
+        else if (!strcmp(ev->key, "z"))
+          {
+             _undo_cb(data, obj, event);
+          }
      }
 }
 
@@ -51,6 +135,7 @@ EAPI Evas_Object *edi_editor_add(Evas_Object *parent, const char *path)
    Evas_Object *txt;
    Evas_Modifier_Mask ctrl, shift, alt;
    Evas *e;
+   Edi_Editor *editor;
 
    txt = elm_entry_add(parent);
    elm_entry_editable_set(txt, EINA_TRUE);
@@ -63,8 +148,12 @@ EAPI Evas_Object *edi_editor_add(Evas_Object *parent, const char *path)
    evas_object_size_hint_align_set(txt, EVAS_HINT_FILL, EVAS_HINT_FILL);
    evas_object_show(txt);
 
+   editor = calloc(1, sizeof(*editor));
+   editor->entry = txt;
    evas_object_event_callback_add(txt, EVAS_CALLBACK_KEY_DOWN,
-                                  _smart_cb_key_down, txt);
+                                  _smart_cb_key_down, editor);
+   evas_object_smart_callback_add(txt, "changed,user", _changed_cb, editor);
+   evas_object_smart_callback_add(txt, "undo,request", _undo_cb, editor);
 
    e = evas_object_evas_get(txt);
    ctrl = evas_key_modifier_mask_get(e, "Control");
@@ -75,6 +164,7 @@ EAPI Evas_Object *edi_editor_add(Evas_Object *parent, const char *path)
    evas_object_key_grab(txt, "Next", ctrl, shift | alt, 1);
    evas_object_key_grab(txt, "s", ctrl, shift | alt, 1);
    evas_object_key_grab(txt, "f", ctrl, shift | alt, 1);
+   evas_object_key_grab(txt, "z", ctrl, shift | alt, 1);
 
    return txt;
 }

src/bin/editor/edi_editor.h

@@ -12,6 +12,26 @@ extern "C" {
  * @brief These routines are used for interacting with the main Edi editor view.
  */
 
+/**
+ * @typedef Edi_Editor
+ * An instance of an editor view.
+ */
+typedef struct _Edi_Editor Edi_Editor;
+
+/**
+ * @struct _Edi_Editor
+ * An instance of an editor view.
+ */
+struct _Edi_Editor
+{
+   Evas_Object *entry; /**< The main text entry widget for the editor */
+   Eina_List *undo_stack; /**< The list of operations that can be undone */
+
+   /* Private */
+
+   /* Add new members here. */
+};
+
 /**
  * @brief Editor.
  * @defgroup Editor The main text editor functions