master d1d311a3b22 2/2: Avoid unnecessary tree-sitter reparse when setting the same range

[Yuan Fu]

branch: master
commit d1d311a3b2222242b1b23fe0b86cd14866fd7cee
Author: Yuan Fu <casouri@gmail.com>
Commit: Yuan Fu <casouri@gmail.com>

    Avoid unnecessary tree-sitter reparse when setting the same range
    
    * src/treesit.h (Lisp_TS_Parser)
    * src/treesit.c (make_treesit_parser): Remove has_range field, add
    last_set_ranges field.
    (Ftreesit_parser_set_included_ranges): Return early if the new range
    is the same as the old one.
    (Ftreesit_parser_included_ranges): Change has_range to
    last_set_ranges.
---
 src/treesit.c | 18 ++++++++++--------
 src/treesit.h |  7 ++++---
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/src/treesit.c b/src/treesit.c
index cc4f5f1998d..570329ca88b 100644
--- a/src/treesit.c
+++ b/src/treesit.c
@@ -1164,6 +1164,7 @@ make_treesit_parser (Lisp_Object buffer, TSParser *parser,
   lisp_parser->language_symbol = language_symbol;
   lisp_parser->after_change_functions = Qnil;
   lisp_parser->tag = tag;
+  lisp_parser->last_set_ranges = Qnil;
   lisp_parser->buffer = buffer;
   lisp_parser->parser = parser;
   lisp_parser->tree = tree;
@@ -1174,7 +1175,6 @@ make_treesit_parser (Lisp_Object buffer, TSParser *parser,
   lisp_parser->visible_end = BUF_ZV_BYTE (XBUFFER (buffer));
   lisp_parser->timestamp = 0;
   lisp_parser->deleted = false;
-  lisp_parser->has_range = false;
   eassert (lisp_parser->visible_beg <= lisp_parser->visible_end);
   return make_lisp_ptr (lisp_parser, Lisp_Vectorlike);
 }
@@ -1656,6 +1656,10 @@ buffer.  */)
   treesit_check_parser (parser);
   if (!NILP (ranges))
     CHECK_CONS (ranges);
+
+  if (Fequal (XTS_PARSER (parser)->last_set_ranges, ranges))
+    return Qnil;
+
   treesit_check_range_argument (ranges);
 
   treesit_initialize ();
@@ -1663,10 +1667,10 @@ buffer.  */)
   treesit_check_buffer_size (XBUFFER (XTS_PARSER (parser)->buffer));
   treesit_sync_visible_region (parser);
 
+  XTS_PARSER (parser)->last_set_ranges = ranges;
   bool success;
   if (NILP (ranges))
     {
-      XTS_PARSER (parser)->has_range = false;
       /* If RANGES is nil, make parser to parse the whole document.
         To do that we give tree-sitter a 0 length, the range is a
         dummy.  */
@@ -1677,8 +1681,6 @@ buffer.  */)
   else
     {
       /* Set ranges for PARSER.  */
-      XTS_PARSER (parser)->has_range = true;
-
       if (list_length (ranges) > UINT32_MAX)
        xsignal (Qargs_out_of_range, list2 (ranges, Flength (ranges)));
       uint32_t len = (uint32_t) list_length (ranges);
@@ -1734,10 +1736,10 @@ See also `treesit-parser-set-included-ranges'.  */)
 
   /* When the parser doesn't have a range set and we call
      ts_parser_included_ranges on it, it doesn't return an empty list,
-     but rather return some garbled data. (A single range where
-     start_byte = 0, end_byte = UINT32_MAX).  So we need to track
-     whether the parser is ranged ourselves.  */
-  if (!XTS_PARSER (parser)->has_range)
+     but rather return DEFAULT_RANGE. (A single range where start_byte
+     = 0, end_byte = UINT32_MAX).  So we need to track whether the
+     parser is ranged ourselves.  */
+  if (NILP (XTS_PARSER (parser)->last_set_ranges))
     return Qnil;
 
   uint32_t len;
diff --git a/src/treesit.h b/src/treesit.h
index ed5bab18733..ef7e2e15317 100644
--- a/src/treesit.h
+++ b/src/treesit.h
@@ -45,6 +45,10 @@ struct Lisp_TS_Parser
      same tag.  A tag is primarily used to differentiate between
      parsers for the same language.  */
   Lisp_Object tag;
+  /* The Lisp ranges last set.  This is use to compare to the new
+     ranges the users wants to set, and avoid reparse if the new
+     ranges is the same as the last set one.  */
+  Lisp_Object last_set_ranges;
   /* The buffer associated with this parser.  */
   Lisp_Object buffer;
   /* The pointer to the tree-sitter parser.  Never NULL.  */
@@ -76,9 +80,6 @@ struct Lisp_TS_Parser
   /* If this field is true, parser functions raises
      treesit-parser-deleted signal.  */
   bool deleted;
-  /* If this field is true, the parser has ranges set.  See
-     Ftreesit_parser_included_ranges for why we need this.  */
-  bool has_range;
 };
 
 /* A wrapper around a tree-sitter node.  */