directory-rename-detection.txt: technical docs on abilities and limitations

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index bd6ac48968dc6b58dbdb70cf9a733985a12d0c03..71056d8294d7f4bcfdcbc9bb292a5d17faf49252 100644 (file)
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -279,6 +279,7 @@ static unsigned long write_no_reuse_object(struct hashfile *f, struct object_ent
        enum object_type type;
        void *buf;
        struct git_istream *st = NULL;
+       const unsigned hashsz = the_hash_algo->rawsz;
 
        if (!usable_delta) {
                if (oe_type(entry) == OBJ_BLOB &&
@@ -335,7 +336,7 @@ static unsigned long write_no_reuse_object(struct hashfile *f, struct object_ent
                dheader[pos] = ofs & 127;
                while (ofs >>= 7)
                        dheader[--pos] = 128 | (--ofs & 127);
-               if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
+               if (limit && hdrlen + sizeof(dheader) - pos + datalen + hashsz >= limit) {
                        if (st)
                                close_istream(st);
                        free(buf);
@@ -347,19 +348,19 @@ static unsigned long write_no_reuse_object(struct hashfile *f, struct object_ent
        } else if (type == OBJ_REF_DELTA) {
                /*
                 * Deltas with a base reference contain
-                * an additional 20 bytes for the base sha1.
+                * additional bytes for the base object ID.
                 */
-               if (limit && hdrlen + 20 + datalen + 20 >= limit) {
+               if (limit && hdrlen + hashsz + datalen + hashsz >= limit) {
                        if (st)
                                close_istream(st);
                        free(buf);
                        return 0;
                }
                hashwrite(f, header, hdrlen);
-               hashwrite(f, DELTA(entry)->idx.oid.hash, 20);
-               hdrlen += 20;
+               hashwrite(f, DELTA(entry)->idx.oid.hash, hashsz);
+               hdrlen += hashsz;
        } else {
-               if (limit && hdrlen + datalen + 20 >= limit) {
+               if (limit && hdrlen + datalen + hashsz >= limit) {
                        if (st)
                                close_istream(st);
                        free(buf);
@@ -391,6 +392,7 @@ static off_t write_reuse_object(struct hashfile *f, struct object_entry *entry,
        unsigned char header[MAX_PACK_OBJECT_HEADER],
                      dheader[MAX_PACK_OBJECT_HEADER];
        unsigned hdrlen;
+       const unsigned hashsz = the_hash_algo->rawsz;
        unsigned long entry_size = SIZE(entry);
 
        if (DELTA(entry))
@@ -427,7 +429,7 @@ static off_t write_reuse_object(struct hashfile *f, struct object_entry *entry,
                dheader[pos] = ofs & 127;
                while (ofs >>= 7)
                        dheader[--pos] = 128 | (--ofs & 127);
-               if (limit && hdrlen + sizeof(dheader) - pos + datalen + 20 >= limit) {
+               if (limit && hdrlen + sizeof(dheader) - pos + datalen + hashsz >= limit) {
                        unuse_pack(&w_curs);
                        return 0;
                }
@@ -436,16 +438,16 @@ static off_t write_reuse_object(struct hashfile *f, struct object_entry *entry,
                hdrlen += sizeof(dheader) - pos;
                reused_delta++;
        } else if (type == OBJ_REF_DELTA) {
-               if (limit && hdrlen + 20 + datalen + 20 >= limit) {
+               if (limit && hdrlen + hashsz + datalen + hashsz >= limit) {
                        unuse_pack(&w_curs);
                        return 0;
                }
                hashwrite(f, header, hdrlen);
-               hashwrite(f, DELTA(entry)->idx.oid.hash, 20);
-               hdrlen += 20;
+               hashwrite(f, DELTA(entry)->idx.oid.hash, hashsz);
+               hdrlen += hashsz;
                reused_delta++;
        } else {
-               if (limit && hdrlen + datalen + 20 >= limit) {
+               if (limit && hdrlen + datalen + hashsz >= limit) {
                        unuse_pack(&w_curs);
                        return 0;
                }
@@ -769,7 +771,7 @@ static off_t write_reused_pack(struct hashfile *f)
                die_errno("unable to seek in reused packfile");
 
        if (reuse_packfile_offset < 0)
-               reuse_packfile_offset = reuse_packfile->pack_size - 20;
+               reuse_packfile_offset = reuse_packfile->pack_size - the_hash_algo->rawsz;
 
        total = to_write = reuse_packfile_offset - sizeof(struct pack_header);
 
@@ -1033,7 +1035,7 @@ static int want_object_in_pack(const struct object_id *oid,
        int want;
        struct list_head *pos;
 
-       if (!exclude && local && has_loose_object_nonlocal(oid->hash))
+       if (!exclude && local && has_loose_object_nonlocal(oid))
                return 0;
 
        /*
@@ -1467,7 +1469,7 @@ static void check_object(struct object_entry *entry)
                        if (reuse_delta && !entry->preferred_base)
                                base_ref = use_pack(p, &w_curs,
                                                entry->in_pack_offset + used, NULL);
-                       entry->in_pack_header_size = used + 20;
+                       entry->in_pack_header_size = used + the_hash_algo->rawsz;
                        break;
                case OBJ_OFS_DELTA:
                        buf = use_pack(p, &w_curs,
@@ -1668,7 +1670,7 @@ static void break_delta_chains(struct object_entry *entry)
                 * is a bug.
                 */
                if (cur->dfs_state != DFS_NONE)
-                       die("BUG: confusing delta dfs state in first pass: %d",
+                       BUG("confusing delta dfs state in first pass: %d",
                            cur->dfs_state);
 
                /*
@@ -1725,7 +1727,7 @@ static void break_delta_chains(struct object_entry *entry)
                if (cur->dfs_state == DFS_DONE)
                        break;
                else if (cur->dfs_state != DFS_ACTIVE)
-                       die("BUG: confusing delta dfs state in second pass: %d",
+                       BUG("confusing delta dfs state in second pass: %d",
                            cur->dfs_state);
 
                /*
@@ -1949,7 +1951,7 @@ static int try_delta(struct unpacked *trg, struct unpacked *src,
        /* Now some size filtering heuristics. */
        trg_size = SIZE(trg_entry);
        if (!DELTA(trg_entry)) {
-               max_size = trg_size/2 - 20;
+               max_size = trg_size/2 - the_hash_algo->rawsz;
                ref_depth = 1;
        } else {
                max_size = DELTA_SIZE(trg_entry);