[evolution] Bug 756707 - calculations of lineno and offset for external editor gvim component is broken

[Tomas Popela <tpopela src gnome org>]

commit f41e8f8522cf3490e2a531f1ed46635d5c6c3ddb
Author: Tomas Popela <tpopela redhat com>
Date:   Tue Oct 20 09:43:13 2015 +0200

    Bug 756707 - calculations of lineno and offset for external editor gvim component is broken
    
    Fix get_caret_position to correctly return number of bytes from the beginning
    of the body to the current caret position and introduce the get_caret_offset
    function to return the number of bytes from the beginning of current line to the
    current caret position. Also the code of the numlines function was adjusted as
    the webkit_dom_range_to_string (used by both previously mentioned functions) is
    returning a text without new line characters, thus when counting the line number
    we cannot increase the counter if we hit a new line character.

 plugins/external-editor/external-editor.c |  112 ++++++++++++++++++++---------
 1 files changed, 79 insertions(+), 33 deletions(-)
---
diff --git a/plugins/external-editor/external-editor.c b/plugins/external-editor/external-editor.c
index d263566..2709c84 100644
--- a/plugins/external-editor/external-editor.c
+++ b/plugins/external-editor/external-editor.c
@@ -239,31 +239,35 @@ numlines (const gchar *text,
        gint ctr = 0;
        gint lineno = 0;
 
-       while (text && *text && ctr <= pos) {
-               if (*text == '\n')
+       while (text && *text && ctr < pos) {
+               if (*text == '\n') {
+                       /* Because the get_caret_position is returning a position
+                        * without new lines, we can't increment the counter when
+                        * we hit the new line. */
                        lineno++;
-
+               } else {
+                       ctr++;
+               }
                text++;
-               ctr++;
+
        }
 
-       if (lineno > 0) {
+       if (lineno > 0)
                lineno++;
-       }
 
        return lineno;
 }
 
 static gint
-get_caret_position (EHTMLEditorView *view)
+get_caret_offset (EHTMLEditorView *view)
 {
+       gint ret_val;
+       gchar *text;
        WebKitDOMDocument *document;
        WebKitDOMDOMWindow *dom_window;
        WebKitDOMDOMSelection *dom_selection;
+       WebKitDOMNode *anchor;
        WebKitDOMRange *range;
-       gint range_count, ret_val;
-       WebKitDOMNodeList *nodes;
-       gulong ii, length;
 
        document = webkit_web_view_get_dom_document (WEBKIT_WEB_VIEW (view));
        dom_window = webkit_dom_document_get_default_view (document);
@@ -275,33 +279,73 @@ get_caret_position (EHTMLEditorView *view)
                return 0;
        }
 
+       webkit_dom_dom_selection_collapse_to_start (dom_selection, NULL);
+       /* Select the text from the current caret position to the beginning of the line. */
+       webkit_dom_dom_selection_modify (dom_selection, "extend", "left", "lineBoundary");
+
        range = webkit_dom_dom_selection_get_range_at (dom_selection, 0, NULL);
-       range_count = 0;
-       nodes = webkit_dom_node_get_child_nodes (
-               webkit_dom_node_get_parent_node (
-                       webkit_dom_dom_selection_get_anchor_node (
-                               dom_selection)));
-       length = webkit_dom_node_list_get_length (nodes);
-       for (ii = 0; ii < length; ii++) {
-               WebKitDOMNode *node;
-
-               node = webkit_dom_node_list_item (nodes, ii);
-               if (webkit_dom_node_is_same_node (
-                       node, webkit_dom_dom_selection_get_anchor_node (dom_selection))) {
-
-                       g_object_unref (node);
-                       break;
-               } else if (WEBKIT_DOM_IS_TEXT (node)) {
-                       gchar *text = webkit_dom_node_get_text_content (node);
-                       range_count += strlen (text);
-                       g_free (text);
+       anchor = webkit_dom_dom_selection_get_anchor_node (dom_selection);
+       text = webkit_dom_range_to_string (range, NULL);
+       ret_val = strlen (text);
+       g_free (text);
+
+       webkit_dom_dom_selection_collapse_to_end (dom_selection, NULL);
+
+       /* In the plain text mode we need to increase the return value by 2 per
+        * citation level because of "> ". */
+       if (!e_html_editor_view_get_html_mode (view)) {
+               WebKitDOMNode *parent = anchor;
+
+               while (parent && !WEBKIT_DOM_IS_HTML_BODY_ELEMENT (parent)) {
+                       if (WEBKIT_DOM_IS_HTML_QUOTE_ELEMENT (parent) &&
+                           element_has_class (WEBKIT_DOM_ELEMENT (parent), "-x-evo-plaintext-quoted"))
+                               ret_val += 2;
+
+                       parent = webkit_dom_node_get_parent_node (parent);
                }
-               g_object_unref (node);
        }
-       g_object_unref (nodes);
 
-       ret_val = webkit_dom_range_get_start_offset (range, NULL) + range_count;
+       g_object_unref (range);
+       g_object_unref (dom_selection);
+
+       return ret_val;
+}
 
+static gint
+get_caret_position (EHTMLEditorView *view)
+{
+       gint ret_val;
+       gchar *text;
+       WebKitDOMDocument *document;
+       WebKitDOMHTMLElement *body;
+       WebKitDOMDOMWindow *dom_window;
+       WebKitDOMDOMSelection *dom_selection;
+       WebKitDOMRange *range, *range_clone;
+
+       document = webkit_web_view_get_dom_document (WEBKIT_WEB_VIEW (view));
+       dom_window = webkit_dom_document_get_default_view (document);
+       dom_selection = webkit_dom_dom_window_get_selection (dom_window);
+       g_object_unref (dom_window);
+
+       if (webkit_dom_dom_selection_get_range_count (dom_selection) < 1) {
+               g_object_unref (dom_selection);
+               return 0;
+       }
+
+       range = webkit_dom_dom_selection_get_range_at (dom_selection, 0, NULL);
+       range_clone = webkit_dom_range_clone_range (range, NULL);
+
+       body = webkit_dom_document_get_body (document);
+       /* Select the text from the beginning of the body to the current caret. */
+       webkit_dom_range_set_start_before (
+               range_clone, webkit_dom_node_get_first_child (WEBKIT_DOM_NODE (body)), NULL);
+
+       /* This is returning a text without new lines! */
+       text = webkit_dom_range_to_string (range_clone, NULL);
+       ret_val = strlen (text);
+       g_free (text);
+
+       g_object_unref (range_clone);
        g_object_unref (range);
        g_object_unref (dom_selection);
 
@@ -368,7 +412,9 @@ external_editor_thread (gpointer user_data)
                gboolean set_nofork;
 
                set_nofork = g_strrstr (editor_cmd, "gvim") != NULL;
-               /* Increment 1 so that entering vim insert mode places you
+
+               offset = get_caret_offset (view);
+               /* Increment by 1 so that entering vim insert mode places you
                 * in the same entry position you were at in the html. */
                offset++;