builtin-bundle - use buffered reads for bundle header

This eliminates all use of byte-at-a-time reading of data in this
function: as Junio noted, a bundle file is seekable so we can
reset the file position to the first part of the pack-file using lseek
after reading the header.

Signed-off-by: Mark Levedahl <mdl123@verizon.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin-bundle.c b/builtin-bundle.c
index b954213f702a5ec8ee0cadf6cb79295272b73ca5..f4b4f034f4cd49f15551e92eb20a2b5412373d90 100644 (file)
--- a/builtin-bundle.c
+++ b/builtin-bundle.c
@@ -44,38 +44,21 @@ struct bundle_header {
        struct ref_list references;
 };
 
-/* this function returns the length of the string */
-static int read_string(int fd, char *buffer, int size)
-{
-       int i;
-       for (i = 0; i < size - 1; i++) {
-               ssize_t count = xread(fd, buffer + i, 1);
-               if (count < 0)
-                       return error("Read error: %s", strerror(errno));
-               if (count == 0) {
-                       i--;
-                       break;
-               }
-               if (buffer[i] == '\n')
-                       break;
-       }
-       buffer[i + 1] = '\0';
-       return i + 1;
-}
-
 /* returns an fd */
 static int read_header(const char *path, struct bundle_header *header) {
        char buffer[1024];
-       int fd = open(path, O_RDONLY);
+       int fd;
+       long fpos;
+       FILE *ffd = fopen(path, "rb");
 
-       if (fd < 0)
+       if (!ffd)
                return error("could not open '%s'", path);
-       if (read_string(fd, buffer, sizeof(buffer)) < 0 ||
+       if (!fgets(buffer, sizeof(buffer), ffd) ||
                        strcmp(buffer, bundle_signature)) {
-               close(fd);
+               fclose(ffd);
                return error("'%s' does not look like a v2 bundle file", path);
        }
-       while (read_string(fd, buffer, sizeof(buffer)) > 0
+       while (fgets(buffer, sizeof(buffer), ffd)
                        && buffer[0] != '\n') {
                int is_prereq = buffer[0] == '-';
                int offset = is_prereq ? 1 : 0;
@@ -97,6 +80,12 @@ static int read_header(const char *path, struct bundle_header *header) {
                add_to_ref_list(sha1, isspace(delim) ?
                                buffer + 41 + offset : "", list);
        }
+       fpos = ftell(ffd);
+       fclose(ffd);
+       fd = open(path, O_RDONLY);
+       if (fd < 0)
+               return error("could not open '%s'", path);
+       lseek(fd, fpos, SEEK_SET);
        return fd;
 }