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
This commit is contained in:
Junio C Hamano
113
sha1_file.c
113
sha1_file.c
@ -877,26 +877,61 @@ void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned l
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return unpack_sha1_rest(&stream, hdr, *size);
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}
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static unsigned long get_delta_base(struct packed_git *p,
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unsigned long offset,
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enum object_type kind,
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unsigned long delta_obj_offset,
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unsigned long *base_obj_offset)
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{
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unsigned char *base_info = (unsigned char *) p->pack_base + offset;
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unsigned long base_offset;
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/* there must be at least 20 bytes left regardless of delta type */
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if (p->pack_size <= offset + 20)
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die("truncated pack file");
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if (kind == OBJ_OFS_DELTA) {
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unsigned used = 0;
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unsigned char c = base_info[used++];
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base_offset = c & 127;
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while (c & 128) {
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base_offset += 1;
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if (!base_offset || base_offset & ~(~0UL >> 7))
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die("offset value overflow for delta base object");
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c = base_info[used++];
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base_offset = (base_offset << 7) + (c & 127);
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}
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base_offset = delta_obj_offset - base_offset;
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if (base_offset >= delta_obj_offset)
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die("delta base offset out of bound");
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offset += used;
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} else if (kind == OBJ_REF_DELTA) {
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/* The base entry _must_ be in the same pack */
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base_offset = find_pack_entry_one(base_info, p);
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if (!base_offset)
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die("failed to find delta-pack base object %s",
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sha1_to_hex(base_info));
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offset += 20;
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} else
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die("I am totally screwed");
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*base_obj_offset = base_offset;
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return offset;
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}
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/* forward declaration for a mutually recursive function */
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static int packed_object_info(struct packed_git *p, unsigned long offset,
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char *type, unsigned long *sizep);
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static int packed_delta_info(struct packed_git *p,
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unsigned long offset,
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enum object_type kind,
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unsigned long obj_offset,
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char *type,
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unsigned long *sizep)
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{
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unsigned long base_offset;
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unsigned char *base_sha1 = (unsigned char *) p->pack_base + offset;
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if (p->pack_size < offset + 20)
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die("truncated pack file");
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/* The base entry _must_ be in the same pack */
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base_offset = find_pack_entry_one(base_sha1, p);
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if (!base_offset)
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die("failed to find delta-pack base object %s",
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sha1_to_hex(base_sha1));
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offset += 20;
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offset = get_delta_base(p, offset, kind, obj_offset, &base_offset);
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/* We choose to only get the type of the base object and
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* ignore potentially corrupt pack file that expects the delta
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@ -959,25 +994,6 @@ static unsigned long unpack_object_header(struct packed_git *p, unsigned long of
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return offset + used;
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}
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int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
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unsigned char *base, unsigned long *sizep,
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enum object_type *kindp)
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{
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unsigned long ptr;
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int status = -1;
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use_packed_git(p);
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ptr = offset;
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ptr = unpack_object_header(p, ptr, kindp, sizep);
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if (*kindp != OBJ_DELTA)
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goto done;
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hashcpy(base, (unsigned char *) p->pack_base + ptr);
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status = 0;
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done:
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unuse_packed_git(p);
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return status;
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}
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void packed_object_info_detail(struct packed_git *p,
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unsigned long offset,
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char *type,
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@ -986,11 +1002,12 @@ void packed_object_info_detail(struct packed_git *p,
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unsigned int *delta_chain_length,
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unsigned char *base_sha1)
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{
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unsigned long val;
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unsigned long obj_offset, val;
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unsigned char *next_sha1;
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enum object_type kind;
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*delta_chain_length = 0;
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obj_offset = offset;
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offset = unpack_object_header(p, offset, &kind, size);
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for (;;) {
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@ -1005,7 +1022,13 @@ void packed_object_info_detail(struct packed_git *p,
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strcpy(type, type_names[kind]);
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*store_size = 0; /* notyet */
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return;
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case OBJ_DELTA:
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case OBJ_OFS_DELTA:
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get_delta_base(p, offset, kind, obj_offset, &offset);
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if (*delta_chain_length == 0) {
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/* TODO: find base_sha1 as pointed by offset */
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}
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break;
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case OBJ_REF_DELTA:
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if (p->pack_size <= offset + 20)
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die("pack file %s records an incomplete delta base",
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p->pack_name);
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@ -1015,6 +1038,7 @@ void packed_object_info_detail(struct packed_git *p,
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offset = find_pack_entry_one(next_sha1, p);
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break;
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}
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obj_offset = offset;
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offset = unpack_object_header(p, offset, &kind, &val);
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(*delta_chain_length)++;
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}
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@ -1023,15 +1047,15 @@ void packed_object_info_detail(struct packed_git *p,
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static int packed_object_info(struct packed_git *p, unsigned long offset,
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char *type, unsigned long *sizep)
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{
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unsigned long size;
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unsigned long size, obj_offset = offset;
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enum object_type kind;
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offset = unpack_object_header(p, offset, &kind, &size);
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if (kind == OBJ_DELTA)
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return packed_delta_info(p, offset, type, sizep);
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switch (kind) {
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case OBJ_OFS_DELTA:
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case OBJ_REF_DELTA:
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return packed_delta_info(p, offset, kind, obj_offset, type, sizep);
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case OBJ_COMMIT:
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case OBJ_TREE:
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case OBJ_BLOB:
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@ -1077,23 +1101,15 @@ static void *unpack_compressed_entry(struct packed_git *p,
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static void *unpack_delta_entry(struct packed_git *p,
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unsigned long offset,
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unsigned long delta_size,
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enum object_type kind,
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unsigned long obj_offset,
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char *type,
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unsigned long *sizep)
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{
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void *delta_data, *result, *base;
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unsigned long result_size, base_size, base_offset;
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unsigned char *base_sha1;
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if (p->pack_size < offset + 20)
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die("truncated pack file");
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/* The base entry _must_ be in the same pack */
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base_sha1 = (unsigned char*)p->pack_base + offset;
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base_offset = find_pack_entry_one(base_sha1, p);
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if (!base_offset)
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die("failed to find delta-pack base object %s",
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sha1_to_hex(base_sha1));
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offset += 20;
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offset = get_delta_base(p, offset, kind, obj_offset, &base_offset);
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base = unpack_entry_gently(p, base_offset, type, &base_size);
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if (!base)
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die("failed to read delta base object at %lu from %s",
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@ -1130,13 +1146,14 @@ static void *unpack_entry(struct pack_entry *entry,
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void *unpack_entry_gently(struct packed_git *p, unsigned long offset,
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char *type, unsigned long *sizep)
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{
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unsigned long size;
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unsigned long size, obj_offset = offset;
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enum object_type kind;
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offset = unpack_object_header(p, offset, &kind, &size);
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switch (kind) {
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case OBJ_DELTA:
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return unpack_delta_entry(p, offset, size, type, sizep);
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case OBJ_OFS_DELTA:
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case OBJ_REF_DELTA:
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return unpack_delta_entry(p, offset, size, kind, obj_offset, type, sizep);
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case OBJ_COMMIT:
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case OBJ_TREE:
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case OBJ_BLOB:
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