treesitter: use new on_bytes interface

This will significantly reduce the parsing work
needed e.g. when rehighlighting after every keypress
in insert mode.

Also add safety check for tree-sitter trying to read
past the end of a line. This can happen after we sent
an incorrect buffer update.

1 files changed, 13 insertions, 14 deletions

diff --git a/src/nvim/lua/treesitter.c b/src/nvim/lua/treesitter.c
index 9a58823d64..8be4b6f376 100644
--- a/src/nvim/lua/treesitter.c
+++ b/src/nvim/lua/treesitter.c
@@ -286,22 +286,21 @@ static const char *input_cb(void *payload, uint32_t byte_index,
   }
   char_u *line = ml_get_buf(bp, position.row+1, false);
   size_t len = STRLEN(line);
-
   if (position.column > len) {
     *bytes_read = 0;
-  } else {
-    size_t tocopy = MIN(len-position.column, BUFSIZE);
-
-    memcpy(buf, line+position.column, tocopy);
-    // Translate embedded \n to NUL
-    memchrsub(buf, '\n', '\0', tocopy);
-    *bytes_read = (uint32_t)tocopy;
-    if (tocopy < BUFSIZE) {
-      // now add the final \n. If it didn't fit, input_cb will be called again
-      // on the same line with advanced column.
-      buf[tocopy] = '\n';
-      (*bytes_read)++;
-    }
+    return "";
+  }
+  size_t tocopy = MIN(len-position.column, BUFSIZE);
+
+  memcpy(buf, line+position.column, tocopy);
+  // Translate embedded \n to NUL
+  memchrsub(buf, '\n', '\0', tocopy);
+  *bytes_read = (uint32_t)tocopy;
+  if (tocopy < BUFSIZE) {
+    // now add the final \n. If it didn't fit, input_cb will be called again
+    // on the same line with advanced column.
+    buf[tocopy] = '\n';
+    (*bytes_read)++;
   }
   return buf;
 #undef BUFSIZE