From 209c554ab45701fb78de77fdcec803fef2c8fd39 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Thu, 21 Sep 2006 00:07:39 -0400 Subject: teach git-unpack-objects about deltas with offset to base For delta resolution to be possible, a list of sha1/offset tuple must be constructed in memory in order to load the appropriate base object. Signed-off-by: Nicolas Pitre Signed-off-by: Junio C Hamano diff --git a/builtin-unpack-objects.c b/builtin-unpack-objects.c index c6c6368..e70a711 100644 --- a/builtin-unpack-objects.c +++ b/builtin-unpack-objects.c @@ -15,7 +15,7 @@ static const char unpack_usage[] = "git-unpack-objects [-n] [-q] [-r] < pack-fil /* We always read in 4kB chunks. */ static unsigned char buffer[4096]; -static unsigned long offset, len; +static unsigned long offset, len, consumed_bytes; static SHA_CTX ctx; /* @@ -51,6 +51,7 @@ static void use(int bytes) die("used more bytes than were available"); len -= bytes; offset += bytes; + consumed_bytes += bytes; } static void *get_data(unsigned long size) @@ -89,35 +90,49 @@ static void *get_data(unsigned long size) struct delta_info { unsigned char base_sha1[20]; + unsigned long base_offset; unsigned long size; void *delta; + unsigned nr; struct delta_info *next; }; static struct delta_info *delta_list; -static void add_delta_to_list(unsigned char *base_sha1, void *delta, unsigned long size) +static void add_delta_to_list(unsigned nr, unsigned const char *base_sha1, + unsigned long base_offset, + void *delta, unsigned long size) { struct delta_info *info = xmalloc(sizeof(*info)); hashcpy(info->base_sha1, base_sha1); + info->base_offset = base_offset; info->size = size; info->delta = delta; + info->nr = nr; info->next = delta_list; delta_list = info; } -static void added_object(unsigned char *sha1, const char *type, void *data, unsigned long size); +struct obj_info { + unsigned long offset; + unsigned char sha1[20]; +}; + +static struct obj_info *obj_list; -static void write_object(void *buf, unsigned long size, const char *type) +static void added_object(unsigned nr, const char *type, void *data, + unsigned long size); + +static void write_object(unsigned nr, void *buf, unsigned long size, + const char *type) { - unsigned char sha1[20]; - if (write_sha1_file(buf, size, type, sha1) < 0) + if (write_sha1_file(buf, size, type, obj_list[nr].sha1) < 0) die("failed to write object"); - added_object(sha1, type, buf, size); + added_object(nr, type, buf, size); } -static void resolve_delta(const char *type, +static void resolve_delta(unsigned nr, const char *type, void *base, unsigned long base_size, void *delta, unsigned long delta_size) { @@ -130,20 +145,23 @@ static void resolve_delta(const char *type, if (!result) die("failed to apply delta"); free(delta); - write_object(result, result_size, type); + write_object(nr, result, result_size, type); free(result); } -static void added_object(unsigned char *sha1, const char *type, void *data, unsigned long size) +static void added_object(unsigned nr, const char *type, void *data, + unsigned long size) { struct delta_info **p = &delta_list; struct delta_info *info; while ((info = *p) != NULL) { - if (!hashcmp(info->base_sha1, sha1)) { + if (!hashcmp(info->base_sha1, obj_list[nr].sha1) || + info->base_offset == obj_list[nr].offset) { *p = info->next; p = &delta_list; - resolve_delta(type, data, size, info->delta, info->size); + resolve_delta(info->nr, type, data, size, + info->delta, info->size); free(info); continue; } @@ -151,7 +169,8 @@ static void added_object(unsigned char *sha1, const char *type, void *data, unsi } } -static void unpack_non_delta_entry(enum object_type kind, unsigned long size) +static void unpack_non_delta_entry(enum object_type kind, unsigned long size, + unsigned nr) { void *buf = get_data(size); const char *type; @@ -164,30 +183,80 @@ static void unpack_non_delta_entry(enum object_type kind, unsigned long size) default: die("bad type %d", kind); } if (!dry_run && buf) - write_object(buf, size, type); + write_object(nr, buf, size, type); free(buf); } -static void unpack_delta_entry(unsigned long delta_size) +static void unpack_delta_entry(enum object_type kind, unsigned long delta_size, + unsigned nr) { void *delta_data, *base; unsigned long base_size; char type[20]; unsigned char base_sha1[20]; - hashcpy(base_sha1, fill(20)); - use(20); + if (kind == OBJ_REF_DELTA) { + hashcpy(base_sha1, fill(20)); + use(20); + delta_data = get_data(delta_size); + if (dry_run || !delta_data) { + free(delta_data); + return; + } + if (!has_sha1_file(base_sha1)) { + hashcpy(obj_list[nr].sha1, null_sha1); + add_delta_to_list(nr, base_sha1, 0, delta_data, delta_size); + return; + } + } else { + unsigned base_found = 0; + unsigned char *pack, c; + unsigned long base_offset; + unsigned lo, mid, hi; - delta_data = get_data(delta_size); - if (dry_run || !delta_data) { - free(delta_data); - return; - } + pack = fill(1); + c = *pack; + use(1); + base_offset = c & 127; + while (c & 128) { + base_offset += 1; + if (!base_offset || base_offset & ~(~0UL >> 7)) + die("offset value overflow for delta base object"); + pack = fill(1); + c = *pack; + use(1); + base_offset = (base_offset << 7) + (c & 127); + } + base_offset = obj_list[nr].offset - base_offset; - if (!has_sha1_file(base_sha1)) { - add_delta_to_list(base_sha1, delta_data, delta_size); - return; + delta_data = get_data(delta_size); + if (dry_run || !delta_data) { + free(delta_data); + return; + } + lo = 0; + hi = nr; + while (lo < hi) { + mid = (lo + hi)/2; + if (base_offset < obj_list[mid].offset) { + hi = mid; + } else if (base_offset > obj_list[mid].offset) { + lo = mid + 1; + } else { + hashcpy(base_sha1, obj_list[mid].sha1); + base_found = !is_null_sha1(base_sha1); + break; + } + } + if (!base_found) { + /* The delta base object is itself a delta that + has not been resolved yet. */ + hashcpy(obj_list[nr].sha1, null_sha1); + add_delta_to_list(nr, null_sha1, base_offset, delta_data, delta_size); + return; + } } + base = read_sha1_file(base_sha1, type, &base_size); if (!base) { error("failed to read delta-pack base object %s", @@ -197,7 +266,7 @@ static void unpack_delta_entry(unsigned long delta_size) has_errors = 1; return; } - resolve_delta(type, base, base_size, delta_data, delta_size); + resolve_delta(nr, type, base, base_size, delta_data, delta_size); free(base); } @@ -208,6 +277,8 @@ static void unpack_one(unsigned nr, unsigned total) unsigned long size; enum object_type type; + obj_list[nr].offset = consumed_bytes; + pack = fill(1); c = *pack; use(1); @@ -216,7 +287,7 @@ static void unpack_one(unsigned nr, unsigned total) shift = 4; while (c & 0x80) { pack = fill(1); - c = *pack++; + c = *pack; use(1); size += (c & 0x7f) << shift; shift += 7; @@ -225,13 +296,14 @@ static void unpack_one(unsigned nr, unsigned total) static unsigned long last_sec; static unsigned last_percent; struct timeval now; - unsigned percentage = (nr * 100) / total; + unsigned percentage = ((nr+1) * 100) / total; gettimeofday(&now, NULL); if (percentage != last_percent || now.tv_sec != last_sec) { last_sec = now.tv_sec; last_percent = percentage; - fprintf(stderr, "%4u%% (%u/%u) done\r", percentage, nr, total); + fprintf(stderr, "%4u%% (%u/%u) done\r", + percentage, (nr+1), total); } } switch (type) { @@ -239,10 +311,11 @@ static void unpack_one(unsigned nr, unsigned total) case OBJ_TREE: case OBJ_BLOB: case OBJ_TAG: - unpack_non_delta_entry(type, size); + unpack_non_delta_entry(type, size, nr); return; case OBJ_REF_DELTA: - unpack_delta_entry(size); + case OBJ_OFS_DELTA: + unpack_delta_entry(type, size, nr); return; default: error("bad object type %d", type); @@ -265,9 +338,10 @@ static void unpack_all(void) die("unknown pack file version %d", ntohl(hdr->hdr_version)); fprintf(stderr, "Unpacking %d objects\n", nr_objects); + obj_list = xmalloc(nr_objects * sizeof(*obj_list)); use(sizeof(struct pack_header)); for (i = 0; i < nr_objects; i++) - unpack_one(i+1, nr_objects); + unpack_one(i, nr_objects); if (delta_list) die("unresolved deltas left after unpacking"); } -- cgit v0.10.2-6-g49f6