emacs-30 76faf7e6091 2/4: Revert "Read more on each call to treesit's buffer reader"

[Yuan Fu]

branch: emacs-30
commit 76faf7e60910ffc29b134fa4d16e3d8c176097a7
Author: Yuan Fu <casouri@gmail.com>
Commit: Yuan Fu <casouri@gmail.com>

    Revert "Read more on each call to treesit's buffer reader"
    
    This reverts commit bf23382f1f2d6ea072db4e4750f8a345f77a3ef2.
    
    We move around the gap, narrow regions, ralloc, etc, and don't have a
    way to invalidate previously given range.  So tree-sitter can't be given
    the full range.
---
 src/treesit.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/src/treesit.c b/src/treesit.c
index ee83486b92a..2b43c505dfa 100644
--- a/src/treesit.c
+++ b/src/treesit.c
@@ -1228,13 +1228,11 @@ treesit_read_buffer (void *parser, uint32_t byte_index,
       beg = NULL;
       len = 0;
     }
-  /* Normal case, read until the gap or visible end.  */
+  /* Normal case, read a character.  */
   else
     {
       beg = (char *) BUF_BYTE_ADDRESS (buffer, byte_pos);
-      ptrdiff_t gap_bytepos = BUF_GPT_BYTE (buffer);
-      len = (byte_pos < gap_bytepos)
-           ? gap_bytepos - byte_pos : visible_end - byte_pos;
+      len = BYTES_BY_CHAR_HEAD ((int) *beg);
     }
   /* We never let tree-sitter to parse buffers that large so this
      assertion should never hit.  */