[Emacs-diffs] scratch/raeburn-startup d939820 1/2: Fix unbalanced input blocking in file-reading specialization.

[Ken Raeburn]

branch: scratch/raeburn-startup
commit d9398209eee4fdd65e1a3107f2c832a32f52a222
Author: Ken Raeburn <address@hidden>
Commit: Ken Raeburn <address@hidden>

    Fix unbalanced input blocking in file-reading specialization.
    
    * src/lread.c (read1): In the branch specialized for reading from a
    file, when looping reading additional bytes for a multibyte character,
    unblock input once before the loop and block it again once after.
---
 src/lread.c |   22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/src/lread.c b/src/lread.c
index e9abe77..6e7e263 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -3418,19 +3418,23 @@ read1 (Lisp_Object readcharfun, int *pch, bool 
first_in_list)
                      i = 0;
                      buf[i++] = c;
                      len = BYTES_BY_CHAR_HEAD (c);
-                     while (i < len)
+                     if (i < len)
                        {
                          unblock_input ();
-                         c = readbyte_from_file (-1, readcharfun);
-                         if (c < 0 || ! TRAILING_CODE_P (c))
+                         while (i < len)
                            {
-                             while (--i > 1)
-                               readbyte_from_file (buf[i], readcharfun);
-                             c = BYTE8_TO_CHAR (buf[0]);
-                             block_input ();
-                             goto have_char_from_file;
+                             c = readbyte_from_file (-1, readcharfun);
+                             if (c < 0 || ! TRAILING_CODE_P (c))
+                               {
+                                 while (--i > 1)
+                                   readbyte_from_file (buf[i], readcharfun);
+                                 c = BYTE8_TO_CHAR (buf[0]);
+                                 block_input ();
+                                 goto have_char_from_file;
+                               }
+                             buf[i++] = c;
                            }
-                         buf[i++] = c;
+                         block_input ();
                        }
                      c = STRING_CHAR (buf);
                      /* fall through */