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author | Junio C Hamano <junkio@cox.net> | 2006-10-22 22:51:42 -0700 |
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committer | Junio C Hamano <junkio@cox.net> | 2006-10-22 22:51:42 -0700 |
commit | 05eb811aa1546b696c6c4d55593cfd4fbef0dce5 (patch) | |
tree | bad8266ba08310f00a1998063c545dd3707fdc3c /builtin-pack-objects.c | |
parent | 02a20456d2c5efccbdd0093ad2a16134f160c218 (diff) | |
parent | 2d477051ef260aad352d63fc7d9c07e4ebb4359b (diff) | |
download | git-05eb811aa1546b696c6c4d55593cfd4fbef0dce5.tar.gz git-05eb811aa1546b696c6c4d55593cfd4fbef0dce5.tar.xz |
Merge branch 'np/pack'
* np/pack:
add the capability for index-pack to read from a stream
index-pack: compare only the first 20-bytes of the key.
git-repack: repo.usedeltabaseoffset
pack-objects: document --delta-base-offset option
allow delta data reuse even if base object is a preferred base
zap a debug remnant
let the GIT native protocol use offsets to delta base when possible
make pack data reuse compatible with both delta types
make git-pack-objects able to create deltas with offset to base
teach git-index-pack about deltas with offset to base
teach git-unpack-objects about deltas with offset to base
introduce delta objects with offset to base
Diffstat (limited to 'builtin-pack-objects.c')
-rw-r--r-- | builtin-pack-objects.c | 252 |
1 files changed, 163 insertions, 89 deletions
diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c index 96c069a81..41e1e7453 100644 --- a/builtin-pack-objects.c +++ b/builtin-pack-objects.c @@ -15,7 +15,7 @@ #include <sys/time.h> #include <signal.h> -static const char pack_usage[] = "git-pack-objects [-q] [--no-reuse-delta] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] [--revs [--unpacked | --all]*] [--stdout | base-name] <ref-list | <object-list]"; +static const char pack_usage[] = "git-pack-objects [-q] [--no-reuse-delta] [--delta-base-offset] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] [--revs [--unpacked | --all]*] [--stdout | base-name] <ref-list | <object-list]"; struct object_entry { unsigned char sha1[20]; @@ -29,6 +29,7 @@ struct object_entry { enum object_type type; enum object_type in_pack_type; /* could be delta */ unsigned long delta_size; /* delta data size (uncompressed) */ +#define in_pack_header_size delta_size /* only when reusing pack data */ struct object_entry *delta; /* delta base object */ struct packed_git *in_pack; /* already in pack */ unsigned int in_pack_offset; @@ -60,6 +61,8 @@ static int non_empty; static int no_reuse_delta; static int local; static int incremental; +static int allow_ofs_delta; + static struct object_entry **sorted_by_sha, **sorted_by_type; static struct object_entry *objects; static int nr_objects, nr_alloc, nr_result; @@ -84,17 +87,25 @@ static int object_ix_hashsz; * Pack index for existing packs give us easy access to the offsets into * corresponding pack file where each object's data starts, but the entries * do not store the size of the compressed representation (uncompressed - * size is easily available by examining the pack entry header). We build - * a hashtable of existing packs (pack_revindex), and keep reverse index - * here -- pack index file is sorted by object name mapping to offset; this - * pack_revindex[].revindex array is an ordered list of offsets, so if you - * know the offset of an object, next offset is where its packed - * representation ends. + * size is easily available by examining the pack entry header). It is + * also rather expensive to find the sha1 for an object given its offset. + * + * We build a hashtable of existing packs (pack_revindex), and keep reverse + * index here -- pack index file is sorted by object name mapping to offset; + * this pack_revindex[].revindex array is a list of offset/index_nr pairs + * ordered by offset, so if you know the offset of an object, next offset + * is where its packed representation ends and the index_nr can be used to + * get the object sha1 from the main index. */ +struct revindex_entry { + unsigned int offset; + unsigned int nr; +}; struct pack_revindex { struct packed_git *p; - unsigned long *revindex; -} *pack_revindex = NULL; + struct revindex_entry *revindex; +}; +static struct pack_revindex *pack_revindex; static int pack_revindex_hashsz; /* @@ -141,14 +152,9 @@ static void prepare_pack_ix(void) static int cmp_offset(const void *a_, const void *b_) { - unsigned long a = *(unsigned long *) a_; - unsigned long b = *(unsigned long *) b_; - if (a < b) - return -1; - else if (a == b) - return 0; - else - return 1; + const struct revindex_entry *a = a_; + const struct revindex_entry *b = b_; + return (a->offset < b->offset) ? -1 : (a->offset > b->offset) ? 1 : 0; } /* @@ -161,25 +167,27 @@ static void prepare_pack_revindex(struct pack_revindex *rix) int i; void *index = p->index_base + 256; - rix->revindex = xmalloc(sizeof(unsigned long) * (num_ent + 1)); + rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1)); for (i = 0; i < num_ent; i++) { unsigned int hl = *((unsigned int *)((char *) index + 24*i)); - rix->revindex[i] = ntohl(hl); + rix->revindex[i].offset = ntohl(hl); + rix->revindex[i].nr = i; } /* This knows the pack format -- the 20-byte trailer * follows immediately after the last object data. */ - rix->revindex[num_ent] = p->pack_size - 20; - qsort(rix->revindex, num_ent, sizeof(unsigned long), cmp_offset); + rix->revindex[num_ent].offset = p->pack_size - 20; + rix->revindex[num_ent].nr = -1; + qsort(rix->revindex, num_ent, sizeof(*rix->revindex), cmp_offset); } -static unsigned long find_packed_object_size(struct packed_git *p, - unsigned long ofs) +static struct revindex_entry * find_packed_object(struct packed_git *p, + unsigned int ofs) { int num; int lo, hi; struct pack_revindex *rix; - unsigned long *revindex; + struct revindex_entry *revindex; num = pack_revindex_ix(p); if (num < 0) die("internal error: pack revindex uninitialized"); @@ -191,10 +199,10 @@ static unsigned long find_packed_object_size(struct packed_git *p, hi = num_packed_objects(p) + 1; do { int mi = (lo + hi) / 2; - if (revindex[mi] == ofs) { - return revindex[mi+1] - ofs; + if (revindex[mi].offset == ofs) { + return revindex + mi; } - else if (ofs < revindex[mi]) + else if (ofs < revindex[mi].offset) hi = mi; else lo = mi + 1; @@ -202,6 +210,20 @@ static unsigned long find_packed_object_size(struct packed_git *p, die("internal error: pack revindex corrupt"); } +static unsigned long find_packed_object_size(struct packed_git *p, + unsigned long ofs) +{ + struct revindex_entry *entry = find_packed_object(p, ofs); + return entry[1].offset - ofs; +} + +static unsigned char *find_packed_object_name(struct packed_git *p, + unsigned long ofs) +{ + struct revindex_entry *entry = find_packed_object(p, ofs); + return (unsigned char *)(p->index_base + 256) + 24 * entry->nr + 4; +} + static void *delta_against(void *buf, unsigned long size, struct object_entry *entry) { unsigned long othersize, delta_size; @@ -232,7 +254,7 @@ static int encode_header(enum object_type type, unsigned long size, unsigned cha int n = 1; unsigned char c; - if (type < OBJ_COMMIT || type > OBJ_DELTA) + if (type < OBJ_COMMIT || type > OBJ_REF_DELTA) die("bad type %d", type); c = (type << 4) | (size & 15); @@ -247,6 +269,10 @@ static int encode_header(enum object_type type, unsigned long size, unsigned cha return n; } +/* + * we are going to reuse the existing object data as is. make + * sure it is not corrupt. + */ static int check_inflate(unsigned char *data, unsigned long len, unsigned long expect) { z_stream stream; @@ -278,32 +304,6 @@ static int check_inflate(unsigned char *data, unsigned long len, unsigned long e return st; } -/* - * we are going to reuse the existing pack entry data. make - * sure it is not corrupt. - */ -static int revalidate_pack_entry(struct object_entry *entry, unsigned char *data, unsigned long len) -{ - enum object_type type; - unsigned long size, used; - - if (pack_to_stdout) - return 0; - - /* the caller has already called use_packed_git() for us, - * so it is safe to access the pack data from mmapped location. - * make sure the entry inflates correctly. - */ - used = unpack_object_header_gently(data, len, &type, &size); - if (!used) - return -1; - if (type == OBJ_DELTA) - used += 20; /* skip base object name */ - data += used; - len -= used; - return check_inflate(data, len, entry->size); -} - static int revalidate_loose_object(struct object_entry *entry, unsigned char *map, unsigned long mapsize) @@ -334,13 +334,10 @@ static unsigned long write_object(struct sha1file *f, enum object_type obj_type; int to_reuse = 0; - if (entry->preferred_base) - return 0; - obj_type = entry->type; if (! entry->in_pack) to_reuse = 0; /* can't reuse what we don't have */ - else if (obj_type == OBJ_DELTA) + else if (obj_type == OBJ_REF_DELTA || obj_type == OBJ_OFS_DELTA) to_reuse = 1; /* check_object() decided it for us */ else if (obj_type != entry->in_pack_type) to_reuse = 0; /* pack has delta which is unusable */ @@ -380,18 +377,35 @@ static unsigned long write_object(struct sha1file *f, if (entry->delta) { buf = delta_against(buf, size, entry); size = entry->delta_size; - obj_type = OBJ_DELTA; + obj_type = (allow_ofs_delta && entry->delta->offset) ? + OBJ_OFS_DELTA : OBJ_REF_DELTA; } /* * The object header is a byte of 'type' followed by zero or - * more bytes of length. For deltas, the 20 bytes of delta - * sha1 follows that. + * more bytes of length. */ hdrlen = encode_header(obj_type, size, header); sha1write(f, header, hdrlen); - if (entry->delta) { - sha1write(f, entry->delta, 20); + if (obj_type == OBJ_OFS_DELTA) { + /* + * Deltas with relative base contain an additional + * encoding of the relative offset for the delta + * base from this object's position in the pack. + */ + unsigned long ofs = entry->offset - entry->delta->offset; + unsigned pos = sizeof(header) - 1; + header[pos] = ofs & 127; + while (ofs >>= 7) + header[--pos] = 128 | (--ofs & 127); + sha1write(f, header + pos, sizeof(header) - pos); + hdrlen += sizeof(header) - pos; + } else if (obj_type == OBJ_REF_DELTA) { + /* + * Deltas with a base reference contain + * an additional 20 bytes for the base sha1. + */ + sha1write(f, entry->delta->sha1, 20); hdrlen += 20; } datalen = sha1write_compressed(f, buf, size); @@ -399,21 +413,40 @@ static unsigned long write_object(struct sha1file *f, } else { struct packed_git *p = entry->in_pack; - use_packed_git(p); - datalen = find_packed_object_size(p, entry->in_pack_offset); - buf = (char *) p->pack_base + entry->in_pack_offset; + if (entry->delta) { + obj_type = (allow_ofs_delta && entry->delta->offset) ? + OBJ_OFS_DELTA : OBJ_REF_DELTA; + reused_delta++; + } + hdrlen = encode_header(obj_type, entry->size, header); + sha1write(f, header, hdrlen); + if (obj_type == OBJ_OFS_DELTA) { + unsigned long ofs = entry->offset - entry->delta->offset; + unsigned pos = sizeof(header) - 1; + header[pos] = ofs & 127; + while (ofs >>= 7) + header[--pos] = 128 | (--ofs & 127); + sha1write(f, header + pos, sizeof(header) - pos); + hdrlen += sizeof(header) - pos; + } else if (obj_type == OBJ_REF_DELTA) { + sha1write(f, entry->delta->sha1, 20); + hdrlen += 20; + } - if (revalidate_pack_entry(entry, buf, datalen)) + use_packed_git(p); + buf = (char *) p->pack_base + + entry->in_pack_offset + + entry->in_pack_header_size; + datalen = find_packed_object_size(p, entry->in_pack_offset) + - entry->in_pack_header_size; + if (!pack_to_stdout && check_inflate(buf, datalen, entry->size)) die("corrupt delta in pack %s", sha1_to_hex(entry->sha1)); sha1write(f, buf, datalen); unuse_packed_git(p); - hdrlen = 0; /* not really */ - if (obj_type == OBJ_DELTA) - reused_delta++; reused++; } - if (obj_type == OBJ_DELTA) + if (entry->delta) written_delta++; written++; return hdrlen + datalen; @@ -423,17 +456,16 @@ static unsigned long write_one(struct sha1file *f, struct object_entry *e, unsigned long offset) { - if (e->offset) + if (e->offset || e->preferred_base) /* offset starts from header size and cannot be zero * if it is written already. */ return offset; - e->offset = offset; - offset += write_object(f, e); - /* if we are deltified, write out its base object. */ + /* if we are deltified, write out its base object first. */ if (e->delta) offset = write_one(f, e->delta, offset); - return offset; + e->offset = offset; + return offset + write_object(f, e); } static void write_pack_file(void) @@ -899,26 +931,64 @@ static void check_object(struct object_entry *entry) char type[20]; if (entry->in_pack && !entry->preferred_base) { - unsigned char base[20]; - unsigned long size; - struct object_entry *base_entry; + struct packed_git *p = entry->in_pack; + unsigned long left = p->pack_size - entry->in_pack_offset; + unsigned long size, used; + unsigned char *buf; + struct object_entry *base_entry = NULL; + + use_packed_git(p); + buf = p->pack_base; + buf += entry->in_pack_offset; /* We want in_pack_type even if we do not reuse delta. * There is no point not reusing non-delta representations. */ - check_reuse_pack_delta(entry->in_pack, - entry->in_pack_offset, - base, &size, - &entry->in_pack_type); + used = unpack_object_header_gently(buf, left, + &entry->in_pack_type, &size); + if (!used || left - used <= 20) + die("corrupt pack for %s", sha1_to_hex(entry->sha1)); /* Check if it is delta, and the base is also an object * we are going to pack. If so we will reuse the existing * delta. */ - if (!no_reuse_delta && - entry->in_pack_type == OBJ_DELTA && - (base_entry = locate_object_entry(base)) && - (!base_entry->preferred_base)) { + if (!no_reuse_delta) { + unsigned char c, *base_name; + unsigned long ofs; + /* there is at least 20 bytes left in the pack */ + switch (entry->in_pack_type) { + case OBJ_REF_DELTA: + base_name = buf + used; + used += 20; + break; + case OBJ_OFS_DELTA: + c = buf[used++]; + ofs = c & 127; + while (c & 128) { + ofs += 1; + if (!ofs || ofs & ~(~0UL >> 7)) + die("delta base offset overflow in pack for %s", + sha1_to_hex(entry->sha1)); + c = buf[used++]; + ofs = (ofs << 7) + (c & 127); + } + if (ofs >= entry->in_pack_offset) + die("delta base offset out of bound for %s", + sha1_to_hex(entry->sha1)); + ofs = entry->in_pack_offset - ofs; + base_name = find_packed_object_name(p, ofs); + break; + default: + base_name = NULL; + } + if (base_name) + base_entry = locate_object_entry(base_name); + } + unuse_packed_git(p); + entry->in_pack_header_size = used; + + if (base_entry) { /* Depth value does not matter - find_deltas() * will never consider reused delta as the @@ -927,9 +997,9 @@ static void check_object(struct object_entry *entry) */ /* uncompressed size of the delta data */ - entry->size = entry->delta_size = size; + entry->size = size; entry->delta = base_entry; - entry->type = OBJ_DELTA; + entry->type = entry->in_pack_type; entry->delta_sibling = base_entry->delta_child; base_entry->delta_child = entry; @@ -1484,6 +1554,10 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix) no_reuse_delta = 1; continue; } + if (!strcmp("--delta-base-offset", arg)) { + allow_ofs_delta = 1; + continue; + } if (!strcmp("--stdout", arg)) { pack_to_stdout = 1; continue; |