[vte] widget: Fix mouse selection to skip trailing unused cells

[Egmont Koblinger <egmontkob src gnome org>]

commit e229ea34cadd21a5afcded56bc7b794e14e86649
Author: Egmont Koblinger <egmont gmail com>
Date:   Mon Nov 26 00:38:13 2018 +0100

    widget: Fix mouse selection to skip trailing unused cells
    
    Regression from commit 4005f653ac7df5475066da7245b87d71f11e2c8b.
    
    https://gitlab.gnome.org/GNOME/vte/issues/68

 src/vte.cc        | 16 ++++++++--------
 src/vterowdata.cc | 13 +++++++++++++
 src/vterowdata.hh |  1 +
 3 files changed, 22 insertions(+), 8 deletions(-)
---
diff --git a/src/vte.cc b/src/vte.cc
index 7f8e10b5..9d8900ec 100644
--- a/src/vte.cc
+++ b/src/vte.cc
@@ -5146,7 +5146,7 @@ Terminal::resolve_selection_endpoint(vte::grid::halfcoords const& rowcolhalf, bo
                         } else {
                                 vte::grid::column_t char_begin, char_end;  /* cell boundaries */
                                 rowdata = find_row_data(row);
-                                if (rowdata && col < rowdata->len) {
+                                if (rowdata && col < _vte_row_data_nonempty_length(rowdata)) {
                                         /* Clicked over a used cell. Check for multi-cell characters. */
                                         char_begin = col;
                                         while (char_begin > 0) {
@@ -5169,7 +5169,7 @@ Terminal::resolve_selection_endpoint(vte::grid::halfcoords const& rowcolhalf, bo
                                         col = char_end;
 
                                 /* Maybe wrap to the beginning of the next line. */
-                                if (col > (rowdata ? rowdata->len : 0)) {
+                                if (col > (rowdata ? _vte_row_data_nonempty_length(rowdata) : 0)) {
                                         col = 0;
                                         row++;
                                 }
@@ -5188,7 +5188,7 @@ Terminal::resolve_selection_endpoint(vte::grid::halfcoords const& rowcolhalf, bo
                                 if (row > 0 &&
                                     (rowdata = find_row_data(row - 1)) != nullptr &&
                                     rowdata->attr.soft_wrapped &&
-                                    (len = rowdata->len) > 0 &&
+                                    (len = _vte_row_data_nonempty_length(rowdata)) > 0 &&
                                     is_same_class(len - 1, row - 1, 0, row) /* invalidates rowdata! */) {
                                         if (!after) {
                                                 col = len - 1;
@@ -5201,7 +5201,7 @@ Terminal::resolve_selection_endpoint(vte::grid::halfcoords const& rowcolhalf, bo
                                         col = 0;  /* end-exclusive */
                                         break;  /* done, don't expand any more */
                                 }
-                        } else if (col >= (rowdata ? rowdata->len : 0)) {
+                        } else if (col >= (rowdata ? _vte_row_data_nonempty_length(rowdata) : 0)) {
                                 /* Clicked over the right margin, or right unused area.
                                  * - If within a word (that is, the last letter in this row, and the first
                                  *   letter of the next row belong to the same word) then select the letter
@@ -5212,7 +5212,7 @@ Terminal::resolve_selection_endpoint(vte::grid::halfcoords const& rowcolhalf, bo
                                  * - Otherwise select the newline only and stop. */
                                 if (rowdata != nullptr &&
                                     rowdata->attr.soft_wrapped) {
-                                        if ((len = rowdata->len) > 0 &&
+                                        if ((len = _vte_row_data_nonempty_length(rowdata)) > 0 &&
                                             is_same_class(len - 1, row, 0, row + 1) /* invalidates rowdata! 
*/) {
                                                 if (!after) {
                                                         col = len - 1;
@@ -5228,7 +5228,7 @@ Terminal::resolve_selection_endpoint(vte::grid::halfcoords const& rowcolhalf, bo
                                         }
                                 } else {
                                         if (!after) {
-                                                col = rowdata ? rowdata->len : 0;  /* end-exclusive */
+                                                col = rowdata ? _vte_row_data_nonempty_length(rowdata) : 0;  
/* end-exclusive */
                                         } else {
                                                 col = 0;  /* end-exclusive */
                                                 row++;
@@ -5261,7 +5261,7 @@ Terminal::resolve_selection_endpoint(vte::grid::halfcoords const& rowcolhalf, bo
                                                 /* Reached a hard newline. */
                                                 break;
                                         }
-                                        len = rowdata->len;
+                                        len = _vte_row_data_nonempty_length(rowdata);
                                         /* len might be smaller than m_column_count if a CJK wrapped */
                                         if (!is_same_class(len - 1, row - 1, col, row) /* invalidates 
rowdata! */) {
                                                 break;
@@ -5278,7 +5278,7 @@ Terminal::resolve_selection_endpoint(vte::grid::halfcoords const& rowcolhalf, bo
                                         if (!rowdata) {
                                                 break;
                                         }
-                                        len = rowdata->len;
+                                        len = _vte_row_data_nonempty_length(rowdata);
                                         bool soft_wrapped = rowdata->attr.soft_wrapped;
                                         /* Move forward within the row. */
                                         for (; col < len - 1; col++) {
diff --git a/src/vterowdata.cc b/src/vterowdata.cc
index 6b8efbdd..88edba1a 100644
--- a/src/vterowdata.cc
+++ b/src/vterowdata.cc
@@ -172,3 +172,16 @@ void _vte_row_data_shrink (VteRowData *row, gulong max_len)
                row->len = max_len;
 }
 
+/* Get the length, ignoring trailing empty cells (with a custom background color). */
+guint16 _vte_row_data_nonempty_length (const VteRowData *row)
+{
+        guint16 len;
+        const VteCell *cell;
+        for (len = row->len; len > 0; len--) {
+                cell = &row->cells[len - 1];
+                if (cell->attr.fragment() || cell->c != 0)
+                        break;
+        }
+        return len;
+}
+
diff --git a/src/vterowdata.hh b/src/vterowdata.hh
index 4191cccb..9d4b2767 100644
--- a/src/vterowdata.hh
+++ b/src/vterowdata.hh
@@ -79,5 +79,6 @@ void _vte_row_data_append (VteRowData *row, const VteCell *cell);
 void _vte_row_data_remove (VteRowData *row, gulong col);
 void _vte_row_data_fill (VteRowData *row, const VteCell *cell, gulong len);
 void _vte_row_data_shrink (VteRowData *row, gulong max_len);
+guint16 _vte_row_data_nonempty_length (const VteRowData *row);
 
 G_END_DECLS