refactor nvim_buf_set_lines to use extmark_splice

src/nvim/api/buffer.c

@@ -27,6 +27,7 @@
 #include "nvim/map_defs.h"
 #include "nvim/map.h"
 #include "nvim/mark.h"
+#include "nvim/ops.h"
 #include "nvim/extmark.h"
 #include "nvim/decoration.h"
 #include "nvim/fileio.h"
@@ -441,6 +442,8 @@ void nvim_buf_set_lines(uint64_t channel_id,
     goto end;
   }
 
+  bcount_t deleted_bytes = MAX(get_region_bytecount(start, end, 0, 0)-1, 0);
+
   // If the size of the range is reducing (ie, new_len < old_len) we
   // need to delete some old_len. We do this at the start, by
   // repeatedly deleting line "start".
@@ -460,6 +463,7 @@ void nvim_buf_set_lines(uint64_t channel_id,
   // new old_len. This is a more efficient operation, as it requires
   // less memory allocation and freeing.
   size_t to_replace = old_len < new_len ? old_len : new_len;
+  bcount_t inserted_bytes = 0;
   for (size_t i = 0; i < to_replace; i++) {
     int64_t lnum = start + (int64_t)i;
 
@@ -472,6 +476,8 @@ void nvim_buf_set_lines(uint64_t channel_id,
       api_set_error(err, kErrorTypeException, "Failed to replace line");
       goto end;
     }
+
+    inserted_bytes += STRLEN(lines[i]) + 1;
     // Mark lines that haven't been passed to the buffer as they need
     // to be freed later
     lines[i] = NULL;
@@ -491,6 +497,8 @@ void nvim_buf_set_lines(uint64_t channel_id,
       goto end;
     }
 
+    inserted_bytes += STRLEN(lines[i]) + 1;
+
     // Same as with replacing, but we also need to free lines
     xfree(lines[i]);
     lines[i] = NULL;
@@ -505,7 +513,11 @@ void nvim_buf_set_lines(uint64_t channel_id,
               (linenr_T)(end - 1),
               MAXLNUM,
               (long)extra,
-              kExtmarkUndo);
+              kExtmarkNOOP);
+
+  extmark_splice(curbuf, (int)start-1, 0, (int)(end-start), 0,
+                 deleted_bytes, (int)(end+extra-1), 0, inserted_bytes,
+                 kExtmarkUndo);
 
   changed_lines((linenr_T)start, 0, (linenr_T)end, (long)extra, true);
   fix_cursor((linenr_T)start, (linenr_T)end, (linenr_T)extra);

src/nvim/ops.c

@@ -1676,17 +1676,14 @@ int op_delete(oparg_T *oap)
 
       curbuf_splice_pending++;
       pos_T startpos = curwin->w_cursor;  // start position for delete
-      bcount_t deleted_bytes = (bcount_t)STRLEN(
-          ml_get(startpos.lnum)) + 1 - startpos.col;
+      bcount_t deleted_bytes = get_region_bytecount(
+          startpos.lnum, oap->end.lnum, startpos.col,
+          oap->end.col) - !oap->inclusive;
       truncate_line(true);        // delete from cursor to end of line
 
       curpos = curwin->w_cursor;  // remember curwin->w_cursor
       curwin->w_cursor.lnum++;
 
-      for (linenr_T i = 1; i <= oap->line_count - 2; i++) {
-        deleted_bytes += (bcount_t)STRLEN(
-            ml_get(startpos.lnum + i)) + 1;
-      }
       del_lines(oap->line_count - 2, false);
 
       // delete from start of line until op_end
@@ -1694,7 +1691,6 @@ int op_delete(oparg_T *oap)
       curwin->w_cursor.col = 0;
       (void)del_bytes((colnr_T)n, !virtual_op,
                       oap->op_type == OP_DELETE && !oap->is_VIsual);
-      deleted_bytes += n;
       curwin->w_cursor = curpos;  // restore curwin->w_cursor
       (void)do_join(2, false, false, false, false);
       curbuf_splice_pending--;
@@ -6303,3 +6299,20 @@ bool op_reg_set_previous(const char name)
   y_previous = &y_regs[i];
   return true;
 }
+
+bcount_t get_region_bytecount(linenr_T start_lnum, linenr_T end_lnum,
+                              colnr_T start_col, colnr_T end_col)
+{
+  const char *first = (const char *)ml_get(start_lnum);
+  bcount_t deleted_bytes = (bcount_t)STRLEN(first) - start_col + 1;
+
+  if (start_lnum == end_lnum) {
+    return deleted_bytes - ((bcount_t)STRLEN(first) - end_col + 1);
+  }
+
+  for (linenr_T i = 1; i <= end_lnum-start_lnum-1; i++) {
+    deleted_bytes += (bcount_t)STRLEN(
+        ml_get(start_lnum + i)) + 1;
+  }
+  return deleted_bytes + end_col + 1;
+}

src/nvim/ops.h

@@ -6,6 +6,7 @@
 #include "nvim/macros.h"
 #include "nvim/ascii.h"
 #include "nvim/types.h"
+#include "nvim/extmark.h"
 #include "nvim/eval/typval.h"
 #include "nvim/os/time.h"
 #include "nvim/normal.h" // for MotionType and oparg_T

test/functional/lua/buffer_updates_spec.lua

@@ -958,6 +958,29 @@ describe('lua: nvim_buf_attach on_bytes', function()
       }
     end)
 
+    it("nvim_buf_set_lines", function()
+      local check_events = setup_eventcheck(verify, {"AAA", "BBB"})
+
+      -- delete
+      command("lua vim.api.nvim_buf_set_lines(0, 0, 1, true, {})")
+
+      check_events {
+        { "test1", "bytes", 1, 3, 0, 0, 0, 1, 0, 4, 0, 0, 0 };
+      }
+
+      -- add
+      command("lua vim.api.nvim_buf_set_lines(0, 0, 0, true, {'asdf'})")
+      check_events {
+        { "test1", "bytes", 1, 4, 0, 0, 0, 0, 0, 0, 1, 0, 5 };
+      }
+
+      -- replace
+      command("lua vim.api.nvim_buf_set_lines(0, 0, 1, true, {'asdf', 'fdsa'})")
+      check_events {
+        { "test1", "bytes", 1, 5, 0, 0, 0, 1, 0, 5, 2, 0, 10 };
+      }
+    end)
+
     teardown(function()
       os.remove "Xtest-reload"
       os.remove "Xtest-undofile"