[evolution] e-widget-undo: Group user actions into a single undo record

[Milan Crha <mcrha src gnome org>]

commit 4791f9372c3352b765ac5e963f8ddd89baa2606d
Author: Milan Crha <mcrha redhat com>
Date:   Thu Feb 17 15:50:44 2022 +0100

    e-widget-undo: Group user actions into a single undo record
    
    This is for the GtkTextView only. It allows to undo/redo operations
    like Replace of a text in a single step, instead of each replaced
    word by single step.

 src/e-util/e-widget-undo.c | 193 ++++++++++++++++++++++++++++++++++-----------
 1 file changed, 148 insertions(+), 45 deletions(-)
---
diff --git a/src/e-util/e-widget-undo.c b/src/e-util/e-widget-undo.c
index 495d80b92b..e05ddad128 100644
--- a/src/e-util/e-widget-undo.c
+++ b/src/e-util/e-widget-undo.c
@@ -37,7 +37,8 @@
 
 typedef enum {
        E_UNDO_INSERT,
-       E_UNDO_DELETE
+       E_UNDO_DELETE,
+       E_UNDO_GROUP
 } EUndoType;
 
 typedef enum {
@@ -47,7 +48,10 @@ typedef enum {
 
 typedef struct _EUndoInfo {
        EUndoType type;
-       gchar *text;
+       union _data {
+               gchar *text;
+               GPtrArray *group; /* EUndoInfo */
+       } data;
        gint position_start;
        gint position_end; /* valid for delete type only */
 } EUndoInfo;
@@ -64,6 +68,9 @@ typedef struct _EUndoData {
 
        gulong insert_handler_id;
        gulong delete_handler_id;
+
+       guint user_action_counter;
+       GPtrArray *user_action_array; /* EUndoInfo * */
 } EUndoData;
 
 static void
@@ -72,7 +79,12 @@ free_undo_info (gpointer ptr)
        EUndoInfo *info = ptr;
 
        if (info) {
-               g_free (info->text);
+               if (info->type == E_UNDO_GROUP) {
+                       if (info->data.group)
+                               g_ptr_array_free (info->data.group, TRUE);
+               } else {
+                       g_free (info->data.text);
+               }
                g_free (info);
        }
 }
@@ -85,6 +97,9 @@ free_undo_data (gpointer ptr)
        if (data) {
                gint ii;
 
+               if (data->user_action_array)
+                       g_ptr_array_free (data->user_action_array, TRUE);
+
                for (ii = 0; ii < data->undo_len; ii++) {
                        free_undo_info (data->undo_stack[ii]);
                }
@@ -114,6 +129,11 @@ push_undo (EUndoData *data,
 {
        gint index;
 
+       if (data->user_action_counter) {
+               g_ptr_array_add (data->user_action_array, info);
+               return;
+       }
+
        reset_redos (data);
 
        if (data->n_undos == data->undo_len) {
@@ -143,12 +163,12 @@ can_merge_insert_undos (EUndoInfo *current_info,
        if (text[0] == '\r' || text[0] == '\n')
                return FALSE;
 
-       len = strlen (current_info->text);
+       len = strlen (current_info->data.text);
        if (position != current_info->position_start + len)
                return FALSE;
 
        if (g_ascii_isspace (text[0])) {
-               if (len <= 0 || !g_ascii_isspace (current_info->text[len - 1]))
+               if (len <= 0 || !g_ascii_isspace (current_info->data.text[len - 1]))
                        return FALSE;
        }
 
@@ -175,16 +195,16 @@ push_insert_undo (GObject *object,
            can_merge_insert_undos (data->current_info, text, text_len, position)) {
                gchar *new_text;
 
-               new_text = g_strdup_printf ("%s%*s", data->current_info->text, text_len, text);
-               g_free (data->current_info->text);
-               data->current_info->text = new_text;
+               new_text = g_strdup_printf ("%s%*s", data->current_info->data.text, text_len, text);
+               g_free (data->current_info->data.text);
+               data->current_info->data.text = new_text;
 
                return;
        }
 
        info = g_new0 (EUndoInfo, 1);
        info->type = E_UNDO_INSERT;
-       info->text = g_strndup (text, text_len);
+       info->data.text = g_strndup (text, text_len);
        info->position_start = position;
 
        push_undo (data, info);
@@ -214,9 +234,9 @@ push_delete_undo (GObject *object,
                if (info->position_start == position_start) {
                        gchar *new_text;
 
-                       new_text = g_strconcat (info->text, text, NULL);
-                       g_free (info->text);
-                       info->text = new_text;
+                       new_text = g_strconcat (info->data.text, text, NULL);
+                       g_free (info->data.text);
+                       info->data.text = new_text;
                        g_free (text);
 
                        info->position_end++;
@@ -225,9 +245,9 @@ push_delete_undo (GObject *object,
                } else if (data->current_info->position_start == position_end) {
                        gchar *new_text;
 
-                       new_text = g_strconcat (text, info->text, NULL);
-                       g_free (info->text);
-                       info->text = new_text;
+                       new_text = g_strconcat (text, info->data.text, NULL);
+                       g_free (info->data.text);
+                       info->data.text = new_text;
                        g_free (text);
 
                        info->position_start = position_start;
@@ -238,7 +258,7 @@ push_delete_undo (GObject *object,
 
        info = g_new0 (EUndoInfo, 1);
        info->type = E_UNDO_DELETE;
-       info->text = text;
+       info->data.text = text;
        info->position_start = position_start;
        info->position_end = position_end;
 
@@ -309,6 +329,55 @@ text_buffer_undo_delete_range_cb (GtkTextBuffer *text_buffer,
                gtk_text_iter_get_offset (end));
 }
 
+static void
+text_buffer_undo_begin_user_action_cb (GtkTextBuffer *text_buffer,
+                                      gpointer user_data)
+{
+       EUndoData *data;
+
+       data = g_object_get_data (G_OBJECT (text_buffer), UNDO_DATA_KEY);
+
+       if (!data)
+               return;
+
+       data->user_action_counter++;
+
+       if (data->user_action_counter == 1 && !data->user_action_array)
+               data->user_action_array = g_ptr_array_new_with_free_func (free_undo_info);
+}
+
+static void
+text_buffer_undo_end_user_action_cb (GtkTextBuffer *text_buffer,
+                                    gpointer user_data)
+{
+       EUndoData *data;
+
+       data = g_object_get_data (G_OBJECT (text_buffer), UNDO_DATA_KEY);
+
+       if (!data || !data->user_action_counter)
+               return;
+
+       data->user_action_counter--;
+
+       if (!data->user_action_counter && data->user_action_array && data->user_action_array->len) {
+               EUndoInfo *info;
+
+               if (data->user_action_array->len == 1) {
+                       info = g_ptr_array_steal_index (data->user_action_array, 0);
+                       data->current_info = info;
+               } else {
+                       info = g_new0 (EUndoInfo, 1);
+                       info->type = E_UNDO_GROUP;
+                       info->data.group = data->user_action_array;
+
+                       data->user_action_array = NULL;
+                       data->current_info = NULL;
+               }
+
+               push_undo (data, info);
+       }
+}
+
 static void
 text_buffer_undo_insert_text (GObject *object,
                               const gchar *text,
@@ -359,6 +428,52 @@ widget_undo_place_cursor_at (GObject *object,
        }
 }
 
+static void
+undo_apply_info (EUndoInfo *info,
+                GObject *object,
+                EUndoDoType todo,
+                void (* insert_func) (GObject *object,
+                       const gchar *text,
+                       gint position),
+                void (* delete_func) (GObject *object,
+                       gint position_start,
+                       gint position_end))
+{
+       if (info->type == E_UNDO_INSERT) {
+               if (todo == E_UNDO_DO_UNDO) {
+                       delete_func (object, info->position_start, info->position_start + g_utf8_strlen 
(info->data.text, -1));
+                       widget_undo_place_cursor_at (object, info->position_start);
+               } else {
+                       insert_func (object, info->data.text, info->position_start);
+                       widget_undo_place_cursor_at (object, info->position_start + g_utf8_strlen 
(info->data.text, -1));
+               }
+       } else if (info->type == E_UNDO_DELETE) {
+               if (todo == E_UNDO_DO_UNDO) {
+                       insert_func (object, info->data.text, info->position_start);
+                       widget_undo_place_cursor_at (object, info->position_start + g_utf8_strlen 
(info->data.text, -1));
+               } else {
+                       delete_func (object, info->position_start, info->position_end);
+                       widget_undo_place_cursor_at (object, info->position_start);
+               }
+       } else if (info->type == E_UNDO_GROUP) {
+               guint ii;
+
+               for (ii = 0; ii < info->data.group->len; ii++) {
+                       EUndoInfo *info2;
+
+                       if (todo == E_UNDO_DO_UNDO)
+                               info2 = g_ptr_array_index (info->data.group, info->data.group->len - ii - 1);
+                       else
+                               info2 = g_ptr_array_index (info->data.group, ii);
+
+                       if (!info2)
+                               continue;
+
+                       undo_apply_info (info2, object, todo, insert_func, delete_func);
+               }
+       }
+}
+
 static void
 undo_do_something (GObject *object,
                    EUndoDoType todo,
@@ -392,23 +507,7 @@ undo_do_something (GObject *object,
        g_signal_handler_block (object, data->insert_handler_id);
        g_signal_handler_block (object, data->delete_handler_id);
 
-       if (info->type == E_UNDO_INSERT) {
-               if (todo == E_UNDO_DO_UNDO) {
-                       delete_func (object, info->position_start, info->position_start + g_utf8_strlen 
(info->text, -1));
-                       widget_undo_place_cursor_at (object, info->position_start);
-               } else {
-                       insert_func (object, info->text, info->position_start);
-                       widget_undo_place_cursor_at (object, info->position_start + g_utf8_strlen 
(info->text, -1));
-               }
-       } else if (info->type == E_UNDO_DELETE) {
-               if (todo == E_UNDO_DO_UNDO) {
-                       insert_func (object, info->text, info->position_start);
-                       widget_undo_place_cursor_at (object, info->position_start + g_utf8_strlen 
(info->text, -1));
-               } else {
-                       delete_func (object, info->position_start, info->position_end);
-                       widget_undo_place_cursor_at (object, info->position_start);
-               }
-       }
+       undo_apply_info (info, object, todo, insert_func, delete_func);
 
        data->current_info = NULL;
 
@@ -428,33 +527,33 @@ undo_describe_info (EUndoInfo *info,
                        return g_strdup (_("Undo “Insert text”"));
                else
                        return g_strdup (_("Redo “Insert text”"));
-               /* if (strlen (info->text) > 15) {
+               /* if (strlen (info->data.text) > 15) {
                        if (undo_type == E_UNDO_DO_UNDO)
-                               return g_strdup_printf (_("Undo “Insert “%.12s...””"), info->text);
+                               return g_strdup_printf (_("Undo “Insert “%.12s...””"), info->data.text);
                        else
-                               return g_strdup_printf (_("Redo “Insert “%.12s...””"), info->text);
+                               return g_strdup_printf (_("Redo “Insert “%.12s...””"), info->data.text);
                }
- *
+
                if (undo_type == E_UNDO_DO_UNDO)
-                       return g_strdup_printf (_("Undo “Insert “%s””"), info->text);
+                       return g_strdup_printf (_("Undo “Insert “%s””"), info->data.text);
                else
-                       return g_strdup_printf (_("Redo “Insert “%s””"), info->text); */
+                       return g_strdup_printf (_("Redo “Insert “%s””"), info->data.text); */
        } else if (info->type == E_UNDO_DELETE) {
                if (undo_type == E_UNDO_DO_UNDO)
                        return g_strdup (_("Undo “Delete text”"));
                else
                        return g_strdup (_("Redo “Delete text”"));
-               /* if (strlen (info->text) > 15) {
+               /* if (strlen (info->data.text) > 15) {
                        if (undo_type == E_UNDO_DO_UNDO)
-                               return g_strdup_printf (_("Undo “Delete “%.12s...””"), info->text);
+                               return g_strdup_printf (_("Undo “Delete “%.12s...””"), info->data.text);
                        else
-                               return g_strdup_printf (_("Redo “Delete “%.12s...””"), info->text);
+                               return g_strdup_printf (_("Redo “Delete “%.12s...””"), info->data.text);
                }
- *
+
                if (undo_type == E_UNDO_DO_UNDO)
-                       return g_strdup_printf (_("Undo “Delete “%s””"), info->text);
+                       return g_strdup_printf (_("Undo “Delete “%s””"), info->data.text);
                else
-                       return g_strdup_printf (_("Redo “Delete “%s””"), info->text); */
+                       return g_strdup_printf (_("Redo “Delete “%s””"), info->data.text); */
        }
 
        return NULL;
@@ -652,6 +751,10 @@ e_widget_undo_attach (GtkWidget *widget,
                data->delete_handler_id = g_signal_connect (
                        text_buffer, "delete-range",
                        G_CALLBACK (text_buffer_undo_delete_range_cb), NULL);
+               g_signal_connect (text_buffer, "begin-user-action",
+                       G_CALLBACK (text_buffer_undo_begin_user_action_cb), NULL);
+               g_signal_connect (text_buffer, "end-user-action",
+                       G_CALLBACK (text_buffer_undo_end_user_action_cb), NULL);
 
                if (focus_tracker)
                        g_signal_connect_swapped (