From 5d4a60033543e063bc9d77ca957de0187fb58fb3 Mon Sep 17 00:00:00 2001 From: Matthias Kestenholz Date: Thu, 3 Aug 2006 17:24:36 +0200 Subject: Make git-pack-objects a builtin Signed-off-by: Matthias Kestenholz Signed-off-by: Junio C Hamano --- builtin-pack-objects.c | 1376 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1376 insertions(+) create mode 100644 builtin-pack-objects.c (limited to 'builtin-pack-objects.c') diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c new file mode 100644 index 0000000000..2301cd5c0f --- /dev/null +++ b/builtin-pack-objects.c @@ -0,0 +1,1376 @@ +#include "builtin.h" +#include "cache.h" +#include "object.h" +#include "blob.h" +#include "commit.h" +#include "tag.h" +#include "tree.h" +#include "delta.h" +#include "pack.h" +#include "csum-file.h" +#include "tree-walk.h" +#include +#include + +static const char pack_usage[] = "git-pack-objects [-q] [--no-reuse-delta] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list"; + +struct object_entry { + unsigned char sha1[20]; + unsigned long size; /* uncompressed size */ + unsigned long offset; /* offset into the final pack file; + * nonzero if already written. + */ + unsigned int depth; /* delta depth */ + unsigned int delta_limit; /* base adjustment for in-pack delta */ + unsigned int hash; /* name hint hash */ + enum object_type type; + enum object_type in_pack_type; /* could be delta */ + unsigned long delta_size; /* delta data size (uncompressed) */ + struct object_entry *delta; /* delta base object */ + struct packed_git *in_pack; /* already in pack */ + unsigned int in_pack_offset; + struct object_entry *delta_child; /* deltified objects who bases me */ + struct object_entry *delta_sibling; /* other deltified objects who + * uses the same base as me + */ + int preferred_base; /* we do not pack this, but is encouraged to + * be used as the base objectto delta huge + * objects against. + */ +}; + +/* + * Objects we are going to pack are collected in objects array (dynamically + * expanded). nr_objects & nr_alloc controls this array. They are stored + * in the order we see -- typically rev-list --objects order that gives us + * nice "minimum seek" order. + * + * sorted-by-sha ans sorted-by-type are arrays of pointers that point at + * elements in the objects array. The former is used to build the pack + * index (lists object names in the ascending order to help offset lookup), + * and the latter is used to group similar things together by try_delta() + * heuristics. + */ + +static unsigned char object_list_sha1[20]; +static int non_empty = 0; +static int no_reuse_delta = 0; +static int local = 0; +static int incremental = 0; +static struct object_entry **sorted_by_sha, **sorted_by_type; +static struct object_entry *objects = NULL; +static int nr_objects = 0, nr_alloc = 0, nr_result = 0; +static const char *base_name; +static unsigned char pack_file_sha1[20]; +static int progress = 1; +static volatile sig_atomic_t progress_update = 0; +static int window = 10; + +/* + * The object names in objects array are hashed with this hashtable, + * to help looking up the entry by object name. Binary search from + * sorted_by_sha is also possible but this was easier to code and faster. + * This hashtable is built after all the objects are seen. + */ +static int *object_ix = NULL; +static int object_ix_hashsz = 0; + +/* + * 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. + */ +struct pack_revindex { + struct packed_git *p; + unsigned long *revindex; +} *pack_revindex = NULL; +static int pack_revindex_hashsz = 0; + +/* + * stats + */ +static int written = 0; +static int written_delta = 0; +static int reused = 0; +static int reused_delta = 0; + +static int pack_revindex_ix(struct packed_git *p) +{ + unsigned long ui = (unsigned long)p; + int i; + + ui = ui ^ (ui >> 16); /* defeat structure alignment */ + i = (int)(ui % pack_revindex_hashsz); + while (pack_revindex[i].p) { + if (pack_revindex[i].p == p) + return i; + if (++i == pack_revindex_hashsz) + i = 0; + } + return -1 - i; +} + +static void prepare_pack_ix(void) +{ + int num; + struct packed_git *p; + for (num = 0, p = packed_git; p; p = p->next) + num++; + if (!num) + return; + pack_revindex_hashsz = num * 11; + pack_revindex = xcalloc(sizeof(*pack_revindex), pack_revindex_hashsz); + for (p = packed_git; p; p = p->next) { + num = pack_revindex_ix(p); + num = - 1 - num; + pack_revindex[num].p = p; + } + /* revindex elements are lazily initialized */ +} + +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; +} + +/* + * Ordered list of offsets of objects in the pack. + */ +static void prepare_pack_revindex(struct pack_revindex *rix) +{ + struct packed_git *p = rix->p; + int num_ent = num_packed_objects(p); + int i; + void *index = p->index_base + 256; + + rix->revindex = xmalloc(sizeof(unsigned long) * (num_ent + 1)); + for (i = 0; i < num_ent; i++) { + unsigned int hl = *((unsigned int *)((char *) index + 24*i)); + rix->revindex[i] = ntohl(hl); + } + /* 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); +} + +static unsigned long find_packed_object_size(struct packed_git *p, + unsigned long ofs) +{ + int num; + int lo, hi; + struct pack_revindex *rix; + unsigned long *revindex; + num = pack_revindex_ix(p); + if (num < 0) + die("internal error: pack revindex uninitialized"); + rix = &pack_revindex[num]; + if (!rix->revindex) + prepare_pack_revindex(rix); + revindex = rix->revindex; + lo = 0; + hi = num_packed_objects(p) + 1; + do { + int mi = (lo + hi) / 2; + if (revindex[mi] == ofs) { + return revindex[mi+1] - ofs; + } + else if (ofs < revindex[mi]) + hi = mi; + else + lo = mi + 1; + } while (lo < hi); + die("internal error: pack revindex corrupt"); +} + +static void *delta_against(void *buf, unsigned long size, struct object_entry *entry) +{ + unsigned long othersize, delta_size; + char type[10]; + void *otherbuf = read_sha1_file(entry->delta->sha1, type, &othersize); + void *delta_buf; + + if (!otherbuf) + die("unable to read %s", sha1_to_hex(entry->delta->sha1)); + delta_buf = diff_delta(otherbuf, othersize, + buf, size, &delta_size, 0); + if (!delta_buf || delta_size != entry->delta_size) + die("delta size changed"); + free(buf); + free(otherbuf); + return delta_buf; +} + +/* + * The per-object header is a pretty dense thing, which is + * - first byte: low four bits are "size", then three bits of "type", + * and the high bit is "size continues". + * - each byte afterwards: low seven bits are size continuation, + * with the high bit being "size continues" + */ +static int encode_header(enum object_type type, unsigned long size, unsigned char *hdr) +{ + int n = 1; + unsigned char c; + + if (type < OBJ_COMMIT || type > OBJ_DELTA) + die("bad type %d", type); + + c = (type << 4) | (size & 15); + size >>= 4; + while (size) { + *hdr++ = c | 0x80; + c = size & 0x7f; + size >>= 7; + n++; + } + *hdr = c; + return n; +} + +static unsigned long write_object(struct sha1file *f, + struct object_entry *entry) +{ + unsigned long size; + char type[10]; + void *buf; + unsigned char header[10]; + unsigned hdrlen, datalen; + 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) + 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 */ + else if (entry->delta) + to_reuse = 0; /* we want to pack afresh */ + else + to_reuse = 1; /* we have it in-pack undeltified, + * and we do not need to deltify it. + */ + + if (! to_reuse) { + buf = read_sha1_file(entry->sha1, type, &size); + if (!buf) + die("unable to read %s", sha1_to_hex(entry->sha1)); + if (size != entry->size) + die("object %s size inconsistency (%lu vs %lu)", + sha1_to_hex(entry->sha1), size, entry->size); + if (entry->delta) { + buf = delta_against(buf, size, entry); + size = entry->delta_size; + obj_type = OBJ_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. + */ + hdrlen = encode_header(obj_type, size, header); + sha1write(f, header, hdrlen); + + if (entry->delta) { + sha1write(f, entry->delta, 20); + hdrlen += 20; + } + datalen = sha1write_compressed(f, buf, size); + free(buf); + } + 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; + 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) + written_delta++; + written++; + return hdrlen + datalen; +} + +static unsigned long write_one(struct sha1file *f, + struct object_entry *e, + unsigned long offset) +{ + if (e->offset) + /* 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 (e->delta) + offset = write_one(f, e->delta, offset); + return offset; +} + +static void write_pack_file(void) +{ + int i; + struct sha1file *f; + unsigned long offset; + struct pack_header hdr; + unsigned last_percent = 999; + int do_progress = 0; + + if (!base_name) + f = sha1fd(1, ""); + else { + f = sha1create("%s-%s.%s", base_name, + sha1_to_hex(object_list_sha1), "pack"); + do_progress = progress; + } + if (do_progress) + fprintf(stderr, "Writing %d objects.\n", nr_result); + + hdr.hdr_signature = htonl(PACK_SIGNATURE); + hdr.hdr_version = htonl(PACK_VERSION); + hdr.hdr_entries = htonl(nr_result); + sha1write(f, &hdr, sizeof(hdr)); + offset = sizeof(hdr); + if (!nr_result) + goto done; + for (i = 0; i < nr_objects; i++) { + offset = write_one(f, objects + i, offset); + if (do_progress) { + unsigned percent = written * 100 / nr_result; + if (progress_update || percent != last_percent) { + fprintf(stderr, "%4u%% (%u/%u) done\r", + percent, written, nr_result); + progress_update = 0; + last_percent = percent; + } + } + } + if (do_progress) + fputc('\n', stderr); + done: + sha1close(f, pack_file_sha1, 1); +} + +static void write_index_file(void) +{ + int i; + struct sha1file *f = sha1create("%s-%s.%s", base_name, + sha1_to_hex(object_list_sha1), "idx"); + struct object_entry **list = sorted_by_sha; + struct object_entry **last = list + nr_result; + unsigned int array[256]; + + /* + * Write the first-level table (the list is sorted, + * but we use a 256-entry lookup to be able to avoid + * having to do eight extra binary search iterations). + */ + for (i = 0; i < 256; i++) { + struct object_entry **next = list; + while (next < last) { + struct object_entry *entry = *next; + if (entry->sha1[0] != i) + break; + next++; + } + array[i] = htonl(next - sorted_by_sha); + list = next; + } + sha1write(f, array, 256 * sizeof(int)); + + /* + * Write the actual SHA1 entries.. + */ + list = sorted_by_sha; + for (i = 0; i < nr_result; i++) { + struct object_entry *entry = *list++; + unsigned int offset = htonl(entry->offset); + sha1write(f, &offset, 4); + sha1write(f, entry->sha1, 20); + } + sha1write(f, pack_file_sha1, 20); + sha1close(f, NULL, 1); +} + +static int locate_object_entry_hash(const unsigned char *sha1) +{ + int i; + unsigned int ui; + memcpy(&ui, sha1, sizeof(unsigned int)); + i = ui % object_ix_hashsz; + while (0 < object_ix[i]) { + if (!memcmp(sha1, objects[object_ix[i]-1].sha1, 20)) + return i; + if (++i == object_ix_hashsz) + i = 0; + } + return -1 - i; +} + +static struct object_entry *locate_object_entry(const unsigned char *sha1) +{ + int i; + + if (!object_ix_hashsz) + return NULL; + + i = locate_object_entry_hash(sha1); + if (0 <= i) + return &objects[object_ix[i]-1]; + return NULL; +} + +static void rehash_objects(void) +{ + int i; + struct object_entry *oe; + + object_ix_hashsz = nr_objects * 3; + if (object_ix_hashsz < 1024) + object_ix_hashsz = 1024; + object_ix = xrealloc(object_ix, sizeof(int) * object_ix_hashsz); + memset(object_ix, 0, sizeof(int) * object_ix_hashsz); + for (i = 0, oe = objects; i < nr_objects; i++, oe++) { + int ix = locate_object_entry_hash(oe->sha1); + if (0 <= ix) + continue; + ix = -1 - ix; + object_ix[ix] = i + 1; + } +} + +static unsigned name_hash(const char *name) +{ + unsigned char c; + unsigned hash = 0; + + /* + * This effectively just creates a sortable number from the + * last sixteen non-whitespace characters. Last characters + * count "most", so things that end in ".c" sort together. + */ + while ((c = *name++) != 0) { + if (isspace(c)) + continue; + hash = (hash >> 2) + (c << 24); + } + return hash; +} + +static int add_object_entry(const unsigned char *sha1, unsigned hash, int exclude) +{ + unsigned int idx = nr_objects; + struct object_entry *entry; + struct packed_git *p; + unsigned int found_offset = 0; + struct packed_git *found_pack = NULL; + int ix, status = 0; + + if (!exclude) { + for (p = packed_git; p; p = p->next) { + struct pack_entry e; + if (find_pack_entry_one(sha1, &e, p)) { + if (incremental) + return 0; + if (local && !p->pack_local) + return 0; + if (!found_pack) { + found_offset = e.offset; + found_pack = e.p; + } + } + } + } + if ((entry = locate_object_entry(sha1)) != NULL) + goto already_added; + + if (idx >= nr_alloc) { + unsigned int needed = (idx + 1024) * 3 / 2; + objects = xrealloc(objects, needed * sizeof(*entry)); + nr_alloc = needed; + } + entry = objects + idx; + nr_objects = idx + 1; + memset(entry, 0, sizeof(*entry)); + memcpy(entry->sha1, sha1, 20); + entry->hash = hash; + + if (object_ix_hashsz * 3 <= nr_objects * 4) + rehash_objects(); + else { + ix = locate_object_entry_hash(entry->sha1); + if (0 <= ix) + die("internal error in object hashing."); + object_ix[-1 - ix] = idx + 1; + } + status = 1; + + already_added: + if (progress_update) { + fprintf(stderr, "Counting objects...%d\r", nr_objects); + progress_update = 0; + } + if (exclude) + entry->preferred_base = 1; + else { + if (found_pack) { + entry->in_pack = found_pack; + entry->in_pack_offset = found_offset; + } + } + return status; +} + +struct pbase_tree_cache { + unsigned char sha1[20]; + int ref; + int temporary; + void *tree_data; + unsigned long tree_size; +}; + +static struct pbase_tree_cache *(pbase_tree_cache[256]); +static int pbase_tree_cache_ix(const unsigned char *sha1) +{ + return sha1[0] % ARRAY_SIZE(pbase_tree_cache); +} +static int pbase_tree_cache_ix_incr(int ix) +{ + return (ix+1) % ARRAY_SIZE(pbase_tree_cache); +} + +static struct pbase_tree { + struct pbase_tree *next; + /* This is a phony "cache" entry; we are not + * going to evict it nor find it through _get() + * mechanism -- this is for the toplevel node that + * would almost always change with any commit. + */ + struct pbase_tree_cache pcache; +} *pbase_tree; + +static struct pbase_tree_cache *pbase_tree_get(const unsigned char *sha1) +{ + struct pbase_tree_cache *ent, *nent; + void *data; + unsigned long size; + char type[20]; + int neigh; + int my_ix = pbase_tree_cache_ix(sha1); + int available_ix = -1; + + /* pbase-tree-cache acts as a limited hashtable. + * your object will be found at your index or within a few + * slots after that slot if it is cached. + */ + for (neigh = 0; neigh < 8; neigh++) { + ent = pbase_tree_cache[my_ix]; + if (ent && !memcmp(ent->sha1, sha1, 20)) { + ent->ref++; + return ent; + } + else if (((available_ix < 0) && (!ent || !ent->ref)) || + ((0 <= available_ix) && + (!ent && pbase_tree_cache[available_ix]))) + available_ix = my_ix; + if (!ent) + break; + my_ix = pbase_tree_cache_ix_incr(my_ix); + } + + /* Did not find one. Either we got a bogus request or + * we need to read and perhaps cache. + */ + data = read_sha1_file(sha1, type, &size); + if (!data) + return NULL; + if (strcmp(type, tree_type)) { + free(data); + return NULL; + } + + /* We need to either cache or return a throwaway copy */ + + if (available_ix < 0) + ent = NULL; + else { + ent = pbase_tree_cache[available_ix]; + my_ix = available_ix; + } + + if (!ent) { + nent = xmalloc(sizeof(*nent)); + nent->temporary = (available_ix < 0); + } + else { + /* evict and reuse */ + free(ent->tree_data); + nent = ent; + } + memcpy(nent->sha1, sha1, 20); + nent->tree_data = data; + nent->tree_size = size; + nent->ref = 1; + if (!nent->temporary) + pbase_tree_cache[my_ix] = nent; + return nent; +} + +static void pbase_tree_put(struct pbase_tree_cache *cache) +{ + if (!cache->temporary) { + cache->ref--; + return; + } + free(cache->tree_data); + free(cache); +} + +static int name_cmp_len(const char *name) +{ + int i; + for (i = 0; name[i] && name[i] != '\n' && name[i] != '/'; i++) + ; + return i; +} + +static void add_pbase_object(struct tree_desc *tree, + const char *name, + int cmplen, + const char *fullname) +{ + struct name_entry entry; + + while (tree_entry(tree,&entry)) { + unsigned long size; + char type[20]; + + if (entry.pathlen != cmplen || + memcmp(entry.path, name, cmplen) || + !has_sha1_file(entry.sha1) || + sha1_object_info(entry.sha1, type, &size)) + continue; + if (name[cmplen] != '/') { + unsigned hash = name_hash(fullname); + add_object_entry(entry.sha1, hash, 1); + return; + } + if (!strcmp(type, tree_type)) { + struct tree_desc sub; + struct pbase_tree_cache *tree; + const char *down = name+cmplen+1; + int downlen = name_cmp_len(down); + + tree = pbase_tree_get(entry.sha1); + if (!tree) + return; + sub.buf = tree->tree_data; + sub.size = tree->tree_size; + + add_pbase_object(&sub, down, downlen, fullname); + pbase_tree_put(tree); + } + } +} + +static unsigned *done_pbase_paths; +static int done_pbase_paths_num; +static int done_pbase_paths_alloc; +static int done_pbase_path_pos(unsigned hash) +{ + int lo = 0; + int hi = done_pbase_paths_num; + while (lo < hi) { + int mi = (hi + lo) / 2; + if (done_pbase_paths[mi] == hash) + return mi; + if (done_pbase_paths[mi] < hash) + hi = mi; + else + lo = mi + 1; + } + return -lo-1; +} + +static int check_pbase_path(unsigned hash) +{ + int pos = (!done_pbase_paths) ? -1 : done_pbase_path_pos(hash); + if (0 <= pos) + return 1; + pos = -pos - 1; + if (done_pbase_paths_alloc <= done_pbase_paths_num) { + done_pbase_paths_alloc = alloc_nr(done_pbase_paths_alloc); + done_pbase_paths = xrealloc(done_pbase_paths, + done_pbase_paths_alloc * + sizeof(unsigned)); + } + done_pbase_paths_num++; + if (pos < done_pbase_paths_num) + memmove(done_pbase_paths + pos + 1, + done_pbase_paths + pos, + (done_pbase_paths_num - pos - 1) * sizeof(unsigned)); + done_pbase_paths[pos] = hash; + return 0; +} + +static void add_preferred_base_object(char *name, unsigned hash) +{ + struct pbase_tree *it; + int cmplen = name_cmp_len(name); + + if (check_pbase_path(hash)) + return; + + for (it = pbase_tree; it; it = it->next) { + if (cmplen == 0) { + hash = name_hash(""); + add_object_entry(it->pcache.sha1, hash, 1); + } + else { + struct tree_desc tree; + tree.buf = it->pcache.tree_data; + tree.size = it->pcache.tree_size; + add_pbase_object(&tree, name, cmplen, name); + } + } +} + +static void add_preferred_base(unsigned char *sha1) +{ + struct pbase_tree *it; + void *data; + unsigned long size; + unsigned char tree_sha1[20]; + + data = read_object_with_reference(sha1, tree_type, &size, tree_sha1); + if (!data) + return; + + for (it = pbase_tree; it; it = it->next) { + if (!memcmp(it->pcache.sha1, tree_sha1, 20)) { + free(data); + return; + } + } + + it = xcalloc(1, sizeof(*it)); + it->next = pbase_tree; + pbase_tree = it; + + memcpy(it->pcache.sha1, tree_sha1, 20); + it->pcache.tree_data = data; + it->pcache.tree_size = size; +} + +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; + + /* 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); + + /* 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)) { + + /* Depth value does not matter - find_deltas() + * will never consider reused delta as the + * base object to deltify other objects + * against, in order to avoid circular deltas. + */ + + /* uncompressed size of the delta data */ + entry->size = entry->delta_size = size; + entry->delta = base_entry; + entry->type = OBJ_DELTA; + + entry->delta_sibling = base_entry->delta_child; + base_entry->delta_child = entry; + + return; + } + /* Otherwise we would do the usual */ + } + + if (sha1_object_info(entry->sha1, type, &entry->size)) + die("unable to get type of object %s", + sha1_to_hex(entry->sha1)); + + if (!strcmp(type, commit_type)) { + entry->type = OBJ_COMMIT; + } else if (!strcmp(type, tree_type)) { + entry->type = OBJ_TREE; + } else if (!strcmp(type, blob_type)) { + entry->type = OBJ_BLOB; + } else if (!strcmp(type, tag_type)) { + entry->type = OBJ_TAG; + } else + die("unable to pack object %s of type %s", + sha1_to_hex(entry->sha1), type); +} + +static unsigned int check_delta_limit(struct object_entry *me, unsigned int n) +{ + struct object_entry *child = me->delta_child; + unsigned int m = n; + while (child) { + unsigned int c = check_delta_limit(child, n + 1); + if (m < c) + m = c; + child = child->delta_sibling; + } + return m; +} + +static void get_object_details(void) +{ + int i; + struct object_entry *entry; + + prepare_pack_ix(); + for (i = 0, entry = objects; i < nr_objects; i++, entry++) + check_object(entry); + + if (nr_objects == nr_result) { + /* + * Depth of objects that depend on the entry -- this + * is subtracted from depth-max to break too deep + * delta chain because of delta data reusing. + * However, we loosen this restriction when we know we + * are creating a thin pack -- it will have to be + * expanded on the other end anyway, so do not + * artificially cut the delta chain and let it go as + * deep as it wants. + */ + for (i = 0, entry = objects; i < nr_objects; i++, entry++) + if (!entry->delta && entry->delta_child) + entry->delta_limit = + check_delta_limit(entry, 1); + } +} + +typedef int (*entry_sort_t)(const struct object_entry *, const struct object_entry *); + +static entry_sort_t current_sort; + +static int sort_comparator(const void *_a, const void *_b) +{ + struct object_entry *a = *(struct object_entry **)_a; + struct object_entry *b = *(struct object_entry **)_b; + return current_sort(a,b); +} + +static struct object_entry **create_sorted_list(entry_sort_t sort) +{ + struct object_entry **list = xmalloc(nr_objects * sizeof(struct object_entry *)); + int i; + + for (i = 0; i < nr_objects; i++) + list[i] = objects + i; + current_sort = sort; + qsort(list, nr_objects, sizeof(struct object_entry *), sort_comparator); + return list; +} + +static int sha1_sort(const struct object_entry *a, const struct object_entry *b) +{ + return memcmp(a->sha1, b->sha1, 20); +} + +static struct object_entry **create_final_object_list(void) +{ + struct object_entry **list; + int i, j; + + for (i = nr_result = 0; i < nr_objects; i++) + if (!objects[i].preferred_base) + nr_result++; + list = xmalloc(nr_result * sizeof(struct object_entry *)); + for (i = j = 0; i < nr_objects; i++) { + if (!objects[i].preferred_base) + list[j++] = objects + i; + } + current_sort = sha1_sort; + qsort(list, nr_result, sizeof(struct object_entry *), sort_comparator); + return list; +} + +static int type_size_sort(const struct object_entry *a, const struct object_entry *b) +{ + if (a->type < b->type) + return -1; + if (a->type > b->type) + return 1; + if (a->hash < b->hash) + return -1; + if (a->hash > b->hash) + return 1; + if (a->preferred_base < b->preferred_base) + return -1; + if (a->preferred_base > b->preferred_base) + return 1; + if (a->size < b->size) + return -1; + if (a->size > b->size) + return 1; + return a < b ? -1 : (a > b); +} + +struct unpacked { + struct object_entry *entry; + void *data; + struct delta_index *index; +}; + +/* + * We search for deltas _backwards_ in a list sorted by type and + * by size, so that we see progressively smaller and smaller files. + * That's because we prefer deltas to be from the bigger file + * to the smaller - deletes are potentially cheaper, but perhaps + * more importantly, the bigger file is likely the more recent + * one. + */ +static int try_delta(struct unpacked *trg, struct unpacked *src, + unsigned max_depth) +{ + struct object_entry *trg_entry = trg->entry; + struct object_entry *src_entry = src->entry; + unsigned long trg_size, src_size, delta_size, sizediff, max_size, sz; + char type[10]; + void *delta_buf; + + /* Don't bother doing diffs between different types */ + if (trg_entry->type != src_entry->type) + return -1; + + /* We do not compute delta to *create* objects we are not + * going to pack. + */ + if (trg_entry->preferred_base) + return -1; + + /* + * We do not bother to try a delta that we discarded + * on an earlier try, but only when reusing delta data. + */ + if (!no_reuse_delta && trg_entry->in_pack && + trg_entry->in_pack == src_entry->in_pack) + return 0; + + /* + * If the current object is at pack edge, take the depth the + * objects that depend on the current object into account -- + * otherwise they would become too deep. + */ + if (trg_entry->delta_child) { + if (max_depth <= trg_entry->delta_limit) + return 0; + max_depth -= trg_entry->delta_limit; + } + if (src_entry->depth >= max_depth) + return 0; + + /* Now some size filtering heuristics. */ + trg_size = trg_entry->size; + max_size = trg_size/2 - 20; + max_size = max_size * (max_depth - src_entry->depth) / max_depth; + if (max_size == 0) + return 0; + if (trg_entry->delta && trg_entry->delta_size <= max_size) + max_size = trg_entry->delta_size-1; + src_size = src_entry->size; + sizediff = src_size < trg_size ? trg_size - src_size : 0; + if (sizediff >= max_size) + return 0; + + /* Load data if not already done */ + if (!trg->data) { + trg->data = read_sha1_file(trg_entry->sha1, type, &sz); + if (sz != trg_size) + die("object %s inconsistent object length (%lu vs %lu)", + sha1_to_hex(trg_entry->sha1), sz, trg_size); + } + if (!src->data) { + src->data = read_sha1_file(src_entry->sha1, type, &sz); + if (sz != src_size) + die("object %s inconsistent object length (%lu vs %lu)", + sha1_to_hex(src_entry->sha1), sz, src_size); + } + if (!src->index) { + src->index = create_delta_index(src->data, src_size); + if (!src->index) + die("out of memory"); + } + + delta_buf = create_delta(src->index, trg->data, trg_size, &delta_size, max_size); + if (!delta_buf) + return 0; + + trg_entry->delta = src_entry; + trg_entry->delta_size = delta_size; + trg_entry->depth = src_entry->depth + 1; + free(delta_buf); + return 1; +} + +static void progress_interval(int signum) +{ + progress_update = 1; +} + +static void find_deltas(struct object_entry **list, int window, int depth) +{ + int i, idx; + unsigned int array_size = window * sizeof(struct unpacked); + struct unpacked *array = xmalloc(array_size); + unsigned processed = 0; + unsigned last_percent = 999; + + memset(array, 0, array_size); + i = nr_objects; + idx = 0; + if (progress) + fprintf(stderr, "Deltifying %d objects.\n", nr_result); + + while (--i >= 0) { + struct object_entry *entry = list[i]; + struct unpacked *n = array + idx; + int j; + + if (!entry->preferred_base) + processed++; + + if (progress) { + unsigned percent = processed * 100 / nr_result; + if (percent != last_percent || progress_update) { + fprintf(stderr, "%4u%% (%u/%u) done\r", + percent, processed, nr_result); + progress_update = 0; + last_percent = percent; + } + } + + if (entry->delta) + /* This happens if we decided to reuse existing + * delta from a pack. "!no_reuse_delta &&" is implied. + */ + continue; + + if (entry->size < 50) + continue; + free_delta_index(n->index); + n->index = NULL; + free(n->data); + n->data = NULL; + n->entry = entry; + + j = window; + while (--j > 0) { + unsigned int other_idx = idx + j; + struct unpacked *m; + if (other_idx >= window) + other_idx -= window; + m = array + other_idx; + if (!m->entry) + break; + if (try_delta(n, m, depth) < 0) + break; + } + /* if we made n a delta, and if n is already at max + * depth, leaving it in the window is pointless. we + * should evict it first. + */ + if (entry->delta && depth <= entry->depth) + continue; + + idx++; + if (idx >= window) + idx = 0; + } + + if (progress) + fputc('\n', stderr); + + for (i = 0; i < window; ++i) { + free_delta_index(array[i].index); + free(array[i].data); + } + free(array); +} + +static void prepare_pack(int window, int depth) +{ + get_object_details(); + sorted_by_type = create_sorted_list(type_size_sort); + if (window && depth) + find_deltas(sorted_by_type, window+1, depth); +} + +static int reuse_cached_pack(unsigned char *sha1, int pack_to_stdout) +{ + static const char cache[] = "pack-cache/pack-%s.%s"; + char *cached_pack, *cached_idx; + int ifd, ofd, ifd_ix = -1; + + cached_pack = git_path(cache, sha1_to_hex(sha1), "pack"); + ifd = open(cached_pack, O_RDONLY); + if (ifd < 0) + return 0; + + if (!pack_to_stdout) { + cached_idx = git_path(cache, sha1_to_hex(sha1), "idx"); + ifd_ix = open(cached_idx, O_RDONLY); + if (ifd_ix < 0) { + close(ifd); + return 0; + } + } + + if (progress) + fprintf(stderr, "Reusing %d objects pack %s\n", nr_objects, + sha1_to_hex(sha1)); + + if (pack_to_stdout) { + if (copy_fd(ifd, 1)) + exit(1); + close(ifd); + } + else { + char name[PATH_MAX]; + snprintf(name, sizeof(name), + "%s-%s.%s", base_name, sha1_to_hex(sha1), "pack"); + ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666); + if (ofd < 0) + die("unable to open %s (%s)", name, strerror(errno)); + if (copy_fd(ifd, ofd)) + exit(1); + close(ifd); + + snprintf(name, sizeof(name), + "%s-%s.%s", base_name, sha1_to_hex(sha1), "idx"); + ofd = open(name, O_CREAT | O_EXCL | O_WRONLY, 0666); + if (ofd < 0) + die("unable to open %s (%s)", name, strerror(errno)); + if (copy_fd(ifd_ix, ofd)) + exit(1); + close(ifd_ix); + puts(sha1_to_hex(sha1)); + } + + return 1; +} + +static void setup_progress_signal(void) +{ + struct sigaction sa; + struct itimerval v; + + memset(&sa, 0, sizeof(sa)); + sa.sa_handler = progress_interval; + sigemptyset(&sa.sa_mask); + sa.sa_flags = SA_RESTART; + sigaction(SIGALRM, &sa, NULL); + + v.it_interval.tv_sec = 1; + v.it_interval.tv_usec = 0; + v.it_value = v.it_interval; + setitimer(ITIMER_REAL, &v, NULL); +} + +static int git_pack_config(const char *k, const char *v) +{ + if(!strcmp(k, "pack.window")) { + window = git_config_int(k, v); + return 0; + } + return git_default_config(k, v); +} + +int cmd_pack_objects(int argc, const char **argv, const char *prefix) +{ + SHA_CTX ctx; + char line[40 + 1 + PATH_MAX + 2]; + int depth = 10, pack_to_stdout = 0; + struct object_entry **list; + int num_preferred_base = 0; + int i; + + git_config(git_pack_config); + + progress = isatty(2); + for (i = 1; i < argc; i++) { + const char *arg = argv[i]; + + if (*arg == '-') { + if (!strcmp("--non-empty", arg)) { + non_empty = 1; + continue; + } + if (!strcmp("--local", arg)) { + local = 1; + continue; + } + if (!strcmp("--progress", arg)) { + progress = 1; + continue; + } + if (!strcmp("--incremental", arg)) { + incremental = 1; + continue; + } + if (!strncmp("--window=", arg, 9)) { + char *end; + window = strtoul(arg+9, &end, 0); + if (!arg[9] || *end) + usage(pack_usage); + continue; + } + if (!strncmp("--depth=", arg, 8)) { + char *end; + depth = strtoul(arg+8, &end, 0); + if (!arg[8] || *end) + usage(pack_usage); + continue; + } + if (!strcmp("--progress", arg)) { + progress = 1; + continue; + } + if (!strcmp("-q", arg)) { + progress = 0; + continue; + } + if (!strcmp("--no-reuse-delta", arg)) { + no_reuse_delta = 1; + continue; + } + if (!strcmp("--stdout", arg)) { + pack_to_stdout = 1; + continue; + } + usage(pack_usage); + } + if (base_name) + usage(pack_usage); + base_name = arg; + } + + if (pack_to_stdout != !base_name) + usage(pack_usage); + + prepare_packed_git(); + + if (progress) { + fprintf(stderr, "Generating pack...\n"); + setup_progress_signal(); + } + + for (;;) { + unsigned char sha1[20]; + unsigned hash; + + if (!fgets(line, sizeof(line), stdin)) { + if (feof(stdin)) + break; + if (!ferror(stdin)) + die("fgets returned NULL, not EOF, not error!"); + if (errno != EINTR) + die("fgets: %s", strerror(errno)); + clearerr(stdin); + continue; + } + + if (line[0] == '-') { + if (get_sha1_hex(line+1, sha1)) + die("expected edge sha1, got garbage:\n %s", + line+1); + if (num_preferred_base++ < window) + add_preferred_base(sha1); + continue; + } + if (get_sha1_hex(line, sha1)) + die("expected sha1, got garbage:\n %s", line); + hash = name_hash(line+41); + add_preferred_base_object(line+41, hash); + add_object_entry(sha1, hash, 0); + } + if (progress) + fprintf(stderr, "Done counting %d objects.\n", nr_objects); + sorted_by_sha = create_final_object_list(); + if (non_empty && !nr_result) + return 0; + + SHA1_Init(&ctx); + list = sorted_by_sha; + for (i = 0; i < nr_result; i++) { + struct object_entry *entry = *list++; + SHA1_Update(&ctx, entry->sha1, 20); + } + SHA1_Final(object_list_sha1, &ctx); + if (progress && (nr_objects != nr_result)) + fprintf(stderr, "Result has %d objects.\n", nr_result); + + if (reuse_cached_pack(object_list_sha1, pack_to_stdout)) + ; + else { + if (nr_result) + prepare_pack(window, depth); + if (progress && pack_to_stdout) { + /* the other end usually displays progress itself */ + struct itimerval v = {{0,},}; + setitimer(ITIMER_REAL, &v, NULL); + signal(SIGALRM, SIG_IGN ); + progress_update = 0; + } + write_pack_file(); + if (!pack_to_stdout) { + write_index_file(); + puts(sha1_to_hex(object_list_sha1)); + } + } + if (progress) + fprintf(stderr, "Total %d, written %d (delta %d), reused %d (delta %d)\n", + nr_result, written, written_delta, reused, reused_delta); + return 0; +} -- cgit v1.2.3