extmarks/bufhl: reimplement using new marktree data structure

Add new "splice" interface for tracking buffer changes at the byte
level. This will later be reused for byte-resolution buffer updates.
(Implementation has been started, but using undocumented "_on_bytes"
option now as interface hasn't been finalized).

Use this interface to improve many edge cases of extmark adjustment.
Changed tests indicate previously incorrect behavior. Adding tests for
more edge cases will be follow-up work (overlaps on_bytes tests)

Don't consider creation/deletion of marks an undoable event by itself.
This behavior was never documented, and imposes  complexity for little gain.

Add nvim__buf_add_decoration temporary API for direct access to the new
implementation. This should be refactored into a proper API for
decorations, probably involving a huge dict.

fixes #11598

1 files changed, 21 insertions, 18 deletions

diff --git a/src/nvim/change.c b/src/nvim/change.c
index 05cacaf2c2..7eb6ea7328 100644
--- a/src/nvim/change.c
+++ b/src/nvim/change.c
@@ -363,15 +363,10 @@ void changed_bytes(linenr_T lnum, colnr_T col)
 ///
 /// Like changed_bytes() but also adjust extmark for "added" bytes.
 /// When "added" is negative text was deleted.
-static void inserted_bytes(linenr_T lnum, colnr_T col, int added)
+static void inserted_bytes(linenr_T lnum, colnr_T col, int old, int new)
 {
-  if (added > 0) {
-    extmark_col_adjust(curbuf, lnum, col+1, 0, added, kExtmarkUndo);
-  } else if (added < 0) {
-    // TODO(bfredl): next revision of extmarks should handle both these
-    // with the same entry point. Also with more sane params..
-    extmark_col_adjust_delete(curbuf, lnum, col+2,
-                              col+(-added)+1, kExtmarkUndo, 0);
+  if (curbuf_splice_pending == 0) {
+    extmark_splice(curbuf, (int)lnum-1, col, 0, old, 0, new, kExtmarkUndo);
   }
 
   changed_bytes(lnum, col);
@@ -391,7 +386,10 @@ void appended_lines_mark(linenr_T lnum, long count)
   // Skip mark_adjust when adding a line after the last one, there can't
   // be marks there. But it's still needed in diff mode.
   if (lnum + count < curbuf->b_ml.ml_line_count || curwin->w_p_diff) {
-    mark_adjust(lnum + 1, (linenr_T)MAXLNUM, count, 0L, false, kExtmarkUndo);
+    mark_adjust(lnum + 1, (linenr_T)MAXLNUM, count, 0L, kExtmarkUndo);
+  } else {
+    extmark_adjust(curbuf, lnum + 1, (linenr_T)MAXLNUM, count, 0L,
+                   kExtmarkUndo);
   }
   changed_lines(lnum + 1, 0, lnum + 1, count, true);
 }
@@ -409,7 +407,7 @@ void deleted_lines(linenr_T lnum, long count)
 /// be triggered to display the cursor.
 void deleted_lines_mark(linenr_T lnum, long count)
 {
-  mark_adjust(lnum, (linenr_T)(lnum + count - 1), (long)MAXLNUM, -count, false,
+  mark_adjust(lnum, (linenr_T)(lnum + count - 1), (long)MAXLNUM, -count,
               kExtmarkUndo);
   changed_lines(lnum, 0, lnum + count, -count, true);
 }
@@ -648,7 +646,7 @@ void ins_char_bytes(char_u *buf, size_t charlen)
   ml_replace(lnum, newp, false);
 
   // mark the buffer as changed and prepare for displaying
-  inserted_bytes(lnum, (colnr_T)col, (int)(newlen - oldlen));
+  inserted_bytes(lnum, (colnr_T)col, (int)oldlen, (int)newlen);
 
   // If we're in Insert or Replace mode and 'showmatch' is set, then briefly
   // show the match for right parens and braces.
@@ -694,7 +692,7 @@ void ins_str(char_u *s)
   assert(bytes >= 0);
   memmove(newp + col + newlen, oldp + col, (size_t)bytes);
   ml_replace(lnum, newp, false);
-  inserted_bytes(lnum, col, newlen);
+  inserted_bytes(lnum, col, 0, newlen);
   curwin->w_cursor.col += newlen;
 }
 
@@ -815,7 +813,7 @@ int del_bytes(colnr_T count, bool fixpos_arg, bool use_delcombine)
   }
 
   // mark the buffer as changed and prepare for displaying
-  inserted_bytes(lnum, col, -count);
+  inserted_bytes(lnum, col, count, 0);
 
   return OK;
 }
@@ -1583,6 +1581,7 @@ int open_line(
     end_comment_pending = NUL;  // turns out there was no leader
   }
 
+  curbuf_splice_pending++;
   old_cursor = curwin->w_cursor;
   if (dir == BACKWARD) {
     curwin->w_cursor.lnum--;
@@ -1597,7 +1596,7 @@ int open_line(
     // be marks there. But still needed in diff mode.
     if (curwin->w_cursor.lnum + 1 < curbuf->b_ml.ml_line_count
         || curwin->w_p_diff) {
-      mark_adjust(curwin->w_cursor.lnum + 1, (linenr_T)MAXLNUM, 1L, 0L, false,
+      mark_adjust(curwin->w_cursor.lnum + 1, (linenr_T)MAXLNUM, 1L, 0L,
                   kExtmarkUndo);
     }
     did_append = true;
@@ -1638,7 +1637,7 @@ int open_line(
       // it.  It gets restored at the function end.
       curbuf->b_p_pi = true;
     } else {
-      (void)set_indent(newindent, SIN_INSERT);
+      (void)set_indent(newindent, SIN_INSERT|SIN_NOMARK);
     }
     less_cols -= curwin->w_cursor.col;
 
@@ -1687,12 +1686,13 @@ int open_line(
         if (flags & OPENLINE_MARKFIX) {
           mark_col_adjust(curwin->w_cursor.lnum,
                           curwin->w_cursor.col + less_cols_off,
-                          1L, (long)-less_cols, 0, kExtmarkNOOP);
+                          1L, (long)-less_cols, 0);
         }
         // Always move extmarks - Here we move only the line where the
         // cursor is, the previous mark_adjust takes care of the lines after
-        extmark_col_adjust(curbuf, lnum, mincol, 1L, (long)-less_cols,
-                           kExtmarkUndo);
+        int cols_added = mincol-1+less_cols_off-less_cols;
+        extmark_splice(curbuf, (int)lnum-1, mincol-1, 0, less_cols_off,
+                       1, cols_added, kExtmarkUndo);
       } else {
         changed_bytes(curwin->w_cursor.lnum, curwin->w_cursor.col);
       }
@@ -1704,7 +1704,10 @@ int open_line(
   }
   if (did_append) {
     changed_lines(curwin->w_cursor.lnum, 0, curwin->w_cursor.lnum, 1L, true);
+    extmark_splice(curbuf, (int)curwin->w_cursor.lnum-1,
+                   0, 0, 0, 1, 0, kExtmarkUndo);
   }
+  curbuf_splice_pending--;
 
   curwin->w_cursor.col = newcol;
   curwin->w_cursor.coladd = 0;