Convert the verify_pack callback to struct object_id

Make the verify_pack_callback take a pointer to struct object_id.
Change the pack checksum to use GIT_MAX_RAWSZ, even though it is not
strictly an object ID.  Doing so ensures resilience against future hash
size changes, and allows us to remove hard-coded assumptions about how
big the buffer needs to be.

Also, use a union to convert the pointer from nth_packed_object_sha1 to
to a pointer to struct object_id.  This behavior is compatible with GCC
and clang and explicitly sanctioned by C11.  The alternatives are to
just perform a cast, which would run afoul of strict aliasing rules, but
should just work, and changing the pointer into an instance of struct
object_id and copying the value.  The latter operation could seriously
bloat memory usage on fsck, which already uses a lot of memory on some
repositories.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/fsck.c b/builtin/fsck.c
index 2f67e8217ec9588fe8ca5ab1fa6db41b907a8bed..a187054dac5731741be19c4e0f206323d3bd0acc 100644 (file)
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -377,7 +377,7 @@ static int fsck_obj(struct object *obj)
        return 0;
 }
 
-static int fsck_obj_buffer(const unsigned char *sha1, enum object_type type,
+static int fsck_obj_buffer(const struct object_id *oid, enum object_type type,
                           unsigned long size, void *buffer, int *eaten)
 {
        /*
@@ -385,10 +385,10 @@ static int fsck_obj_buffer(const unsigned char *sha1, enum object_type type,
         * verify_packfile(), data_valid variable for details.
         */
        struct object *obj;
-       obj = parse_object_buffer(sha1, type, size, buffer, eaten);
+       obj = parse_object_buffer(oid->hash, type, size, buffer, eaten);
        if (!obj) {
                errors_found |= ERROR_OBJECT;
-               return error("%s: object corrupt or missing", sha1_to_hex(sha1));
+               return error("%s: object corrupt or missing", oid_to_hex(oid));
        }
        obj->flags = HAS_OBJ;
        return fsck_obj(obj);

diff --git a/pack-check.c b/pack-check.c
index 27f70d345fbf1b339cb4bad1011253cece1bf619..e1fcb228fa126e34528e9d5a38b81a6b2eae2f2a 100644 (file)
--- a/pack-check.c
+++ b/pack-check.c
@@ -5,7 +5,10 @@
 
 struct idx_entry {
        off_t                offset;
-       const unsigned char *sha1;
+       union idx_entry_object {
+               const unsigned char *hash;
+               struct object_id *oid;
+       } oid;
        unsigned int nr;
 };
 
@@ -51,7 +54,7 @@ static int verify_packfile(struct packed_git *p,
        off_t index_size = p->index_size;
        const unsigned char *index_base = p->index_data;
        git_SHA_CTX ctx;
-       unsigned char sha1[20], *pack_sig;
+       unsigned char hash[GIT_MAX_RAWSZ], *pack_sig;
        off_t offset = 0, pack_sig_ofs = 0;
        uint32_t nr_objects, i;
        int err = 0;
@@ -71,9 +74,9 @@ static int verify_packfile(struct packed_git *p,
                        remaining -= (unsigned int)(offset - pack_sig_ofs);
                git_SHA1_Update(&ctx, in, remaining);
        } while (offset < pack_sig_ofs);
-       git_SHA1_Final(sha1, &ctx);
+       git_SHA1_Final(hash, &ctx);
        pack_sig = use_pack(p, w_curs, pack_sig_ofs, NULL);
-       if (hashcmp(sha1, pack_sig))
+       if (hashcmp(hash, pack_sig))
                err = error("%s SHA1 checksum mismatch",
                            p->pack_name);
        if (hashcmp(index_base + index_size - 40, pack_sig))
@@ -90,8 +93,8 @@ static int verify_packfile(struct packed_git *p,
        entries[nr_objects].offset = pack_sig_ofs;
        /* first sort entries by pack offset, since unpacking them is more efficient that way */
        for (i = 0; i < nr_objects; i++) {
-               entries[i].sha1 = nth_packed_object_sha1(p, i);
-               if (!entries[i].sha1)
+               entries[i].oid.hash = nth_packed_object_sha1(p, i);
+               if (!entries[i].oid.hash)
                        die("internal error pack-check nth-packed-object");
                entries[i].offset = nth_packed_object_offset(p, i);
                entries[i].nr = i;
@@ -112,7 +115,7 @@ static int verify_packfile(struct packed_git *p,
                        if (check_pack_crc(p, w_curs, offset, len, nr))
                                err = error("index CRC mismatch for object %s "
                                            "from %s at offset %"PRIuMAX"",
-                                           sha1_to_hex(entries[i].sha1),
+                                           oid_to_hex(entries[i].oid.oid),
                                            p->pack_name, (uintmax_t)offset);
                }
 
@@ -135,14 +138,14 @@ static int verify_packfile(struct packed_git *p,
 
                if (data_valid && !data)
                        err = error("cannot unpack %s from %s at offset %"PRIuMAX"",
-                                   sha1_to_hex(entries[i].sha1), p->pack_name,
+                                   oid_to_hex(entries[i].oid.oid), p->pack_name,
                                    (uintmax_t)entries[i].offset);
-               else if (check_sha1_signature(entries[i].sha1, data, size, typename(type)))
+               else if (check_sha1_signature(entries[i].oid.hash, data, size, typename(type)))
                        err = error("packed %s from %s is corrupt",
-                                   sha1_to_hex(entries[i].sha1), p->pack_name);
+                                   oid_to_hex(entries[i].oid.oid), p->pack_name);
                else if (fn) {
                        int eaten = 0;
-                       err |= fn(entries[i].sha1, type, size, data, &eaten);
+                       err |= fn(entries[i].oid.oid, type, size, data, &eaten);
                        if (eaten)
                                data = NULL;
                }

diff --git a/pack.h b/pack.h
index c7de42ef34a7640800480c2d9700a62bcf8b69da..8294341af174ad67693006dfcb49a7208732f45b 100644 (file)
--- a/pack.h
+++ b/pack.h
@@ -75,7 +75,7 @@ struct pack_idx_entry {
 
 struct progress;
 /* Note, the data argument could be NULL if object type is blob */
-typedef int (*verify_fn)(const unsigned char*, enum object_type, unsigned long, void*, int*);
+typedef int (*verify_fn)(const struct object_id *, enum object_type, unsigned long, void*, int*);
 
 extern const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects, int nr_objects, const struct pack_idx_option *, const unsigned char *sha1);
 extern int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr);