diff options
| -rw-r--r-- | Documentation/git-pack-objects.txt | 21 | ||||
| -rw-r--r-- | pack-objects.c | 102 |
2 files changed, 91 insertions, 32 deletions
diff --git a/Documentation/git-pack-objects.txt b/Documentation/git-pack-objects.txt index 2d67d3911..4cb2e83fa 100644 --- a/Documentation/git-pack-objects.txt +++ b/Documentation/git-pack-objects.txt @@ -8,7 +8,10 @@ git-pack-objects - Create a packed archive of objects. SYNOPSIS -------- -'git-pack-objects' [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list +[verse] +'git-pack-objects' [-q] [--no-reuse-delta] [--non-empty] + [--local] [--incremental] [--window=N] [--depth=N] + {--stdout | base-name} < object-list DESCRIPTION @@ -32,6 +35,10 @@ Placing both in the pack/ subdirectory of $GIT_OBJECT_DIRECTORY (or any of the directories on $GIT_ALTERNATE_OBJECT_DIRECTORIES) enables git to read from such an archive. +In a packed archive, an object is either stored as a compressed +whole, or as a difference from some other object. The latter is +often called a delta. + OPTIONS ------- @@ -74,6 +81,18 @@ base-name:: Only create a packed archive if it would contain at least one object. +-q:: + This flag makes the command not to report its progress + on the standard error stream. + +--no-reuse-delta:: + When creating a packed archive in a repository that + has existing packs, the command reuses existing deltas. + This sometimes results in a slightly suboptimal pack. + This flag tells the command not to reuse existing deltas + but compute them from scratch. + + Author ------ Written by Linus Torvalds <torvalds@osdl.org> diff --git a/pack-objects.c b/pack-objects.c index 70fb2afeb..38e1c9921 100644 --- a/pack-objects.c +++ b/pack-objects.c @@ -5,7 +5,7 @@ #include "csum-file.h" #include <sys/time.h> -static const char pack_usage[] = "git-pack-objects [-q] [--non-empty] [--local] [--incremental] [--window=N] [--depth=N] {--stdout | base-name} < object-list"; +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]; @@ -14,10 +14,11 @@ struct object_entry { unsigned int depth; /* delta depth */ unsigned int hash; /* name hint hash */ enum object_type type; + unsigned char edge; /* reused delta chain points at this entry. */ + 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 */ - enum object_type in_pack_type; /* could be delta */ unsigned int in_pack_offset; }; @@ -36,6 +37,7 @@ struct object_entry { 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; @@ -75,7 +77,9 @@ 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) { @@ -227,10 +231,23 @@ static unsigned long write_object(struct sha1file *f, struct object_entry *entry unsigned char header[10]; unsigned hdrlen, datalen; enum object_type obj_type; + int to_reuse = 0; obj_type = entry->type; - if (!entry->in_pack || - (obj_type != entry->in_pack_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)); @@ -266,8 +283,12 @@ static unsigned long write_object(struct sha1file *f, struct object_entry *entry 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; } @@ -294,7 +315,6 @@ static void write_pack_file(void) int i; struct sha1file *f; unsigned long offset; - unsigned long mb; struct pack_header hdr; if (!base_name) @@ -357,10 +377,9 @@ static int add_object_entry(unsigned char *sha1, unsigned int hash) unsigned int idx = nr_objects; struct object_entry *entry; struct packed_git *p; - unsigned int found_offset; - struct packed_git *found_pack; + unsigned int found_offset = 0; + struct packed_git *found_pack = NULL; - found_pack = NULL; for (p = packed_git; p; p = p->next) { struct pack_entry e; if (find_pack_entry_one(sha1, &e, p)) { @@ -420,32 +439,39 @@ static void check_object(struct object_entry *entry) char type[20]; if (entry->in_pack) { + 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. */ - unsigned char base[20]; - unsigned long size; - struct object_entry *base_entry; - if (!check_reuse_pack_delta(entry->in_pack, - entry->in_pack_offset, - base, &size, - &entry->in_pack_type) && + if (!no_reuse_delta && + entry->in_pack_type == OBJ_DELTA && (base_entry = locate_object_entry(base))) { - /* We do not know depth at this point, but it - * does not matter. Getting delta_chain_length - * with packed_object_info_detail() is not so - * expensive, so we could do that later if we - * wanted to. Calling sha1_object_info to get - * the true size (and later an uncompressed - * representation) of deeply deltified object - * is quite expensive. + + /* 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. */ - entry->depth = 1; - /* uncompressed size */ + + /* uncompressed size of the delta data */ entry->size = entry->delta_size = size; entry->delta = base_entry; entry->type = OBJ_DELTA; + + base_entry->edge = 1; + return; } /* Otherwise we would do the usual */ @@ -568,6 +594,13 @@ static int try_delta(struct unpacked *cur, struct unpacked *old, unsigned max_de if (cur_entry->type != old_entry->type) return -1; + /* If the current object is at edge, take the depth the objects + * that depend on the current object into account -- otherwise + * they would become too deep. + */ + if (cur_entry->edge) + max_depth /= 4; + size = cur_entry->size; if (size < 50) return -1; @@ -627,7 +660,7 @@ static void find_deltas(struct object_entry **list, int window, int depth) if (entry->delta) /* This happens if we decided to reuse existing - * delta from a pack. + * delta from a pack. "!no_reuse_delta &&" is implied. */ continue; @@ -636,6 +669,7 @@ static void find_deltas(struct object_entry **list, int window, int depth) n->data = read_sha1_file(entry->sha1, type, &size); if (size != entry->size) die("object %s inconsistent object length (%lu vs %lu)", sha1_to_hex(entry->sha1), size, entry->size); + j = window; while (--j > 0) { unsigned int other_idx = idx + j; @@ -664,7 +698,7 @@ static void prepare_pack(int window, int depth) fprintf(stderr, "Packing %d objects", nr_objects); get_object_details(); if (progress) - fprintf(stderr, "."); + fputc('.', stderr); sorted_by_type = create_sorted_list(type_size_sort); if (window && depth) @@ -694,8 +728,9 @@ static int reuse_cached_pack(unsigned char *sha1, int pack_to_stdout) } } - fprintf(stderr, "Reusing %d objects pack %s\n", nr_objects, - sha1_to_hex(sha1)); + 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)) @@ -775,6 +810,10 @@ int main(int argc, char **argv) progress = 0; continue; } + if (!strcmp("--no-reuse-delta", arg)) { + no_reuse_delta = 1; + continue; + } if (!strcmp("--stdout", arg)) { pack_to_stdout = 1; continue; @@ -850,7 +889,8 @@ int main(int argc, char **argv) puts(sha1_to_hex(object_list_sha1)); } } - fprintf(stderr, "Total %d, written %d, reused %d\n", - nr_objects, written, reused); + if (progress) + fprintf(stderr, "Total %d, written %d (delta %d), reused %d (delta %d)\n", + nr_objects, written, written_delta, reused, reused_delta); return 0; } |