Refactor replace_encoding_header.

* Be more clever in how we search for "encoding ...\n": parse for real
  instead of the sloppy strstr's.
* use strbuf_splice to do the substring replacements.

Signed-off-by: Pierre Habouzit <madcoder@debian.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/commit.c b/commit.c
index 6602e2c..13af933 100644 (file)
--- a/commit.c
+++ b/commit.c
@@ -648,47 +648,34 @@ static char *get_header(const struct commit *commit, const char *key)
 
 static char *replace_encoding_header(char *buf, const char *encoding)
 {
-       char *encoding_header = strstr(buf, "\nencoding ");
-       char *header_end = strstr(buf, "\n\n");
-       char *end_of_encoding_header;
-       int encoding_header_pos;
-       int encoding_header_len;
-       int new_len;
-       int need_len;
-       int buflen = strlen(buf) + 1;
-
-       if (!header_end)
-               header_end = buf + buflen;
-       if (!encoding_header || encoding_header >= header_end)
-               return buf;
-       encoding_header++;
-       end_of_encoding_header = strchr(encoding_header, '\n');
-       if (!end_of_encoding_header)
+       struct strbuf tmp;
+       size_t start, len;
+       char *cp = buf;
+
+       /* guess if there is an encoding header before a \n\n */
+       while (strncmp(cp, "encoding ", strlen("encoding "))) {
+               cp = strchr(cp, '\n');
+               if (!cp || *++cp == '\n')
+                       return buf;
+       }
+       start = cp - buf;
+       cp = strchr(cp, '\n');
+       if (!cp)
                return buf; /* should not happen but be defensive */
-       end_of_encoding_header++;
-
-       encoding_header_len = end_of_encoding_header - encoding_header;
-       encoding_header_pos = encoding_header - buf;
+       len = cp + 1 - (buf + start);
 
+       strbuf_init(&tmp, 0);
+       strbuf_attach(&tmp, buf, strlen(buf), strlen(buf) + 1);
        if (is_encoding_utf8(encoding)) {
                /* we have re-coded to UTF-8; drop the header */
-               memmove(encoding_header, end_of_encoding_header,
-                       buflen - (encoding_header_pos + encoding_header_len));
-               return buf;
-       }
-       new_len = strlen(encoding);
-       need_len = new_len + strlen("encoding \n");
-       if (encoding_header_len < need_len) {
-               buf = xrealloc(buf, buflen + (need_len - encoding_header_len));
-               encoding_header = buf + encoding_header_pos;
-               end_of_encoding_header = encoding_header + encoding_header_len;
+               strbuf_splice(&tmp, start, len, NULL, 0);
+       } else {
+               /* just replaces XXXX in 'encoding XXXX\n' */
+               strbuf_splice(&tmp, start + strlen("encoding "),
+                                         len - strlen("encoding \n"),
+                                         encoding, strlen(encoding));
        }
-       memmove(end_of_encoding_header + (need_len - encoding_header_len),
-               end_of_encoding_header,
-               buflen - (encoding_header_pos + encoding_header_len));
-       memcpy(encoding_header + 9, encoding, strlen(encoding));
-       encoding_header[9 + new_len] = '\n';
-       return buf;
+       return tmp.buf;
 }
 
 static char *logmsg_reencode(const struct commit *commit,