object-file.c: use "enum" return type for unpack_loose_header()

In a preceding commit we changed and documented unpack_loose_header()
from its previous behavior of returning any negative value or zero, to
only -1 or 0.

Let's add an "enum unpack_loose_header_result" type and use it for
these return values, and have the compiler assert that we're
exhaustively covering all of them.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/cache.h b/cache.h
index 11d2482e3099bcefeb9e0b2ab01d145e9d46fb82..f7382756633c63e33466a64206be4915ea39e02c 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -1307,7 +1307,10 @@ int git_open_cloexec(const char *name, int flags);
  * unpack_loose_header() initializes the data stream needed to unpack
  * a loose object header.
  *
- * Returns 0 on success. Returns negative values on error.
+ * Returns:
+ *
+ * - ULHR_OK on success
+ * - ULHR_BAD on error
  *
  * It will only parse up to MAX_HEADER_LEN bytes unless an optional
  * "hdrbuf" argument is non-NULL. This is intended for use with
@@ -1315,9 +1318,17 @@ int git_open_cloexec(const char *name, int flags);
  * reporting. The full header will be extracted to "hdrbuf" for use
  * with parse_loose_header().
  */
-int unpack_loose_header(git_zstream *stream, unsigned char *map,
-                       unsigned long mapsize, void *buffer,
-                       unsigned long bufsiz, struct strbuf *hdrbuf);
+enum unpack_loose_header_result {
+       ULHR_OK,
+       ULHR_BAD,
+};
+enum unpack_loose_header_result unpack_loose_header(git_zstream *stream,
+                                                   unsigned char *map,
+                                                   unsigned long mapsize,
+                                                   void *buffer,
+                                                   unsigned long bufsiz,
+                                                   struct strbuf *hdrbuf);
+
 struct object_info;
 int parse_loose_header(const char *hdr, struct object_info *oi,
                       unsigned int flags);

diff --git a/object-file.c b/object-file.c
index 59b38aac2b83d452b049e063bf0d80d9bc51f787..ade5f33f3c960d9deb0bb4e131dff855e739027b 100644 (file)
--- a/object-file.c
+++ b/object-file.c
@@ -1210,10 +1210,12 @@ void *map_loose_object(struct repository *r,
        return map_loose_object_1(r, NULL, oid, size);
 }
 
-int unpack_loose_header(git_zstream *stream,
-                       unsigned char *map, unsigned long mapsize,
-                       void *buffer, unsigned long bufsiz,
-                       struct strbuf *header)
+enum unpack_loose_header_result unpack_loose_header(git_zstream *stream,
+                                                   unsigned char *map,
+                                                   unsigned long mapsize,
+                                                   void *buffer,
+                                                   unsigned long bufsiz,
+                                                   struct strbuf *header)
 {
        int status;
 
@@ -1229,13 +1231,13 @@ int unpack_loose_header(git_zstream *stream,
        status = git_inflate(stream, 0);
        obj_read_lock();
        if (status < Z_OK)
-               return -1;
+               return ULHR_BAD;
 
        /*
         * Check if entire header is unpacked in the first iteration.
         */
        if (memchr(buffer, '\0', stream->next_out - (unsigned char *)buffer))
-               return 0;
+               return ULHR_OK;
 
        /*
         * We have a header longer than MAX_HEADER_LEN. The "header"
@@ -1243,7 +1245,7 @@ int unpack_loose_header(git_zstream *stream,
         * --allow-unknown-type".
         */
        if (!header)
-               return -1;
+               return ULHR_BAD;
 
        /*
         * buffer[0..bufsiz] was not large enough.  Copy the partial
@@ -1264,7 +1266,7 @@ int unpack_loose_header(git_zstream *stream,
                stream->next_out = buffer;
                stream->avail_out = bufsiz;
        } while (status != Z_STREAM_END);
-       return -1;
+       return ULHR_BAD;
 }
 
 static void *unpack_loose_rest(git_zstream *stream,
@@ -1429,13 +1431,19 @@ static int loose_object_info(struct repository *r,
        if (oi->disk_sizep)
                *oi->disk_sizep = mapsize;
 
-       if (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr),
-                               allow_unknown ? &hdrbuf : NULL) < 0)
+       switch (unpack_loose_header(&stream, map, mapsize, hdr, sizeof(hdr),
+                                   allow_unknown ? &hdrbuf : NULL)) {
+       case ULHR_OK:
+               break;
+       case ULHR_BAD:
                status = error(_("unable to unpack %s header"),
                               oid_to_hex(oid));
-       if (status < 0)
-               ; /* Do nothing */
-       else if (hdrbuf.len) {
+               break;
+       }
+
+       if (status < 0) {
+               /* Do nothing */
+       } else if (hdrbuf.len) {
                if ((status = parse_loose_header(hdrbuf.buf, oi, flags)) < 0)
                        status = error(_("unable to parse %s header with --allow-unknown-type"),
                                       oid_to_hex(oid));

diff --git a/streaming.c b/streaming.c
index cb3c3cf6ff62f6097bfb05f3c72eaa1002ba2ffd..6df0247a4cb5bedca5406cce392a5b708b74a761 100644 (file)
--- a/streaming.c
+++ b/streaming.c
@@ -229,17 +229,16 @@ static int open_istream_loose(struct git_istream *st, struct repository *r,
        st->u.loose.mapped = map_loose_object(r, oid, &st->u.loose.mapsize);
        if (!st->u.loose.mapped)
                return -1;
-       if ((unpack_loose_header(&st->z,
-                                st->u.loose.mapped,
-                                st->u.loose.mapsize,
-                                st->u.loose.hdr,
-                                sizeof(st->u.loose.hdr),
-                                NULL) < 0) ||
-           (parse_loose_header(st->u.loose.hdr, &oi, 0) < 0)) {
-               git_inflate_end(&st->z);
-               munmap(st->u.loose.mapped, st->u.loose.mapsize);
-               return -1;
+       switch (unpack_loose_header(&st->z, st->u.loose.mapped,
+                                   st->u.loose.mapsize, st->u.loose.hdr,
+                                   sizeof(st->u.loose.hdr), NULL)) {
+       case ULHR_OK:
+               break;
+       case ULHR_BAD:
+               goto error;
        }
+       if (parse_loose_header(st->u.loose.hdr, &oi, 0) < 0)
+               goto error;
 
        st->u.loose.hdr_used = strlen(st->u.loose.hdr) + 1;
        st->u.loose.hdr_avail = st->z.total_out;
@@ -248,6 +247,10 @@ static int open_istream_loose(struct git_istream *st, struct repository *r,
        st->read = read_istream_loose;
 
        return 0;
+error:
+       git_inflate_end(&st->z);
+       munmap(st->u.loose.mapped, st->u.loose.mapsize);
+       return -1;
 }