patch-id.c: use strbuf instead of a fixed buffer

get_one_patchid() uses a rather dumb heuristic to determine if the
passed buffer is part of the next commit. Whenever the first 40 bytes
are a valid hexadecimal sha1 representation, get_one_patchid() returns
next_sha1.

Once the current line is longer than the fixed buffer, this will break
(provided the additional bytes make a valid hexadecimal sha1). As a result
patch-id returns incorrect results. Instead, use strbuf and read one line
at a time.

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Michael Schubert <mschub@elegosoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/patch-id.c b/builtin/patch-id.c
index f821eb3f0b864c26d5e822cc7c5b0747340abee5..3cfe02d5a5716de1a3aaa5edc1ca0e3d74c03b03 100644 (file)
--- a/builtin/patch-id.c
+++ b/builtin/patch-id.c
@@ -56,13 +56,13 @@ static int scan_hunk_header(const char *p, int *p_before, int *p_after)
        return 1;
 }
 
-static int get_one_patchid(unsigned char *next_sha1, git_SHA_CTX *ctx)
+static int get_one_patchid(unsigned char *next_sha1, git_SHA_CTX *ctx, struct strbuf *line_buf)
 {
-       static char line[1000];
        int patchlen = 0, found_next = 0;
        int before = -1, after = -1;
 
-       while (fgets(line, sizeof(line), stdin) != NULL) {
+       while (strbuf_getwholeline(line_buf, stdin, '\n') != EOF) {
+               char *line = line_buf->buf;
                char *p = line;
                int len;
 
@@ -133,14 +133,16 @@ static void generate_id_list(void)
        unsigned char sha1[20], n[20];
        git_SHA_CTX ctx;
        int patchlen;
+       struct strbuf line_buf = STRBUF_INIT;
 
        git_SHA1_Init(&ctx);
        hashclr(sha1);
        while (!feof(stdin)) {
-               patchlen = get_one_patchid(n, &ctx);
+               patchlen = get_one_patchid(n, &ctx, &line_buf);
                flush_current_id(patchlen, sha1, &ctx);
                hashcpy(sha1, n);
        }
+       strbuf_release(&line_buf);
 }
 
 static const char patch_id_usage[] = "git patch-id < patch";