git/builtin-pack-objects.c
Junio C Hamano 45bde46bfb Merge branch 'dh/pack'
* dh/pack:
  Custom compression levels for objects and packs
2007-05-20 02:19:19 -07:00

1742 lines
44 KiB
C

#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 "diff.h"
#include "revision.h"
#include "list-objects.h"
#include "progress.h"
static const char pack_usage[] = "\
git-pack-objects [{ -q | --progress | --all-progress }] \n\
[--local] [--incremental] [--window=N] [--depth=N] \n\
[--no-reuse-delta] [--no-reuse-object] [--delta-base-offset] \n\
[--non-empty] [--revs [--unpacked | --all]*] [--reflog] \n\
[--stdout | base-name] [<ref-list | <object-list]";
struct object_entry {
unsigned char sha1[20];
uint32_t crc32; /* crc of raw pack data for this object */
off_t offset; /* offset into the final pack file */
unsigned long size; /* uncompressed size */
unsigned int hash; /* name hint hash */
unsigned int depth; /* delta depth */
struct packed_git *in_pack; /* already in pack */
off_t in_pack_offset;
struct object_entry *delta; /* delta base object */
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
*/
unsigned long delta_size; /* delta data size (uncompressed) */
enum object_type type;
enum object_type in_pack_type; /* could be delta */
unsigned char in_pack_header_size;
unsigned char preferred_base; /* we do not pack this, but is available
* to be used as the base objectto delta
* 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.
*/
static struct object_entry *objects;
static uint32_t nr_objects, nr_alloc, nr_result;
static int non_empty;
static int no_reuse_delta, no_reuse_object;
static int local;
static int incremental;
static int allow_ofs_delta;
static const char *pack_tmp_name, *idx_tmp_name;
static char tmpname[PATH_MAX];
static unsigned char pack_file_sha1[20];
static int progress = 1;
static int window = 10;
static int depth = 50;
static int pack_to_stdout;
static int num_preferred_base;
static struct progress progress_state;
static int pack_compression_level = Z_DEFAULT_COMPRESSION;
static int pack_compression_seen;
/*
* The object names in objects array are hashed with this hashtable,
* to help looking up the entry by object name.
* This hashtable is built after all the objects are seen.
*/
static int *object_ix;
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). 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 {
off_t offset;
unsigned int nr;
};
struct pack_revindex {
struct packed_git *p;
struct revindex_entry *revindex;
};
static struct pack_revindex *pack_revindex;
static int pack_revindex_hashsz;
/*
* stats
*/
static uint32_t written, written_delta;
static uint32_t reused, reused_delta;
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_)
{
const struct revindex_entry *a = a_;
const struct revindex_entry *b = b_;
return (a->offset < b->offset) ? -1 : (a->offset > b->offset) ? 1 : 0;
}
/*
* 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 = p->num_objects;
int i;
const char *index = p->index_data;
rix->revindex = xmalloc(sizeof(*rix->revindex) * (num_ent + 1));
index += 4 * 256;
if (p->index_version > 1) {
const uint32_t *off_32 =
(uint32_t *)(index + 8 + p->num_objects * (20 + 4));
const uint32_t *off_64 = off_32 + p->num_objects;
for (i = 0; i < num_ent; i++) {
uint32_t off = ntohl(*off_32++);
if (!(off & 0x80000000)) {
rix->revindex[i].offset = off;
} else {
rix->revindex[i].offset =
((uint64_t)ntohl(*off_64++)) << 32;
rix->revindex[i].offset |=
ntohl(*off_64++);
}
rix->revindex[i].nr = i;
}
} else {
for (i = 0; i < num_ent; i++) {
uint32_t hl = *((uint32_t *)(index + 24 * i));
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].offset = p->pack_size - 20;
rix->revindex[num_ent].nr = -1;
qsort(rix->revindex, num_ent, sizeof(*rix->revindex), cmp_offset);
}
static struct revindex_entry * find_packed_object(struct packed_git *p,
off_t ofs)
{
int num;
int lo, hi;
struct pack_revindex *rix;
struct revindex_entry *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 = p->num_objects + 1;
do {
int mi = (lo + hi) / 2;
if (revindex[mi].offset == ofs) {
return revindex + mi;
}
else if (ofs < revindex[mi].offset)
hi = mi;
else
lo = mi + 1;
} while (lo < hi);
die("internal error: pack revindex corrupt");
}
static const unsigned char *find_packed_object_name(struct packed_git *p,
off_t ofs)
{
struct revindex_entry *entry = find_packed_object(p, ofs);
return nth_packed_object_sha1(p, entry->nr);
}
static void *delta_against(void *buf, unsigned long size, struct object_entry *entry)
{
unsigned long othersize, delta_size;
enum object_type type;
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_REF_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;
}
/*
* we are going to reuse the existing object data as is. make
* sure it is not corrupt.
*/
static int check_pack_inflate(struct packed_git *p,
struct pack_window **w_curs,
off_t offset,
off_t len,
unsigned long expect)
{
z_stream stream;
unsigned char fakebuf[4096], *in;
int st;
memset(&stream, 0, sizeof(stream));
inflateInit(&stream);
do {
in = use_pack(p, w_curs, offset, &stream.avail_in);
stream.next_in = in;
stream.next_out = fakebuf;
stream.avail_out = sizeof(fakebuf);
st = inflate(&stream, Z_FINISH);
offset += stream.next_in - in;
} while (st == Z_OK || st == Z_BUF_ERROR);
inflateEnd(&stream);
return (st == Z_STREAM_END &&
stream.total_out == expect &&
stream.total_in == len) ? 0 : -1;
}
static int check_pack_crc(struct packed_git *p, struct pack_window **w_curs,
off_t offset, off_t len, unsigned int nr)
{
const uint32_t *index_crc;
uint32_t data_crc = crc32(0, Z_NULL, 0);
do {
unsigned int avail;
void *data = use_pack(p, w_curs, offset, &avail);
if (avail > len)
avail = len;
data_crc = crc32(data_crc, data, avail);
offset += avail;
len -= avail;
} while (len);
index_crc = p->index_data;
index_crc += 2 + 256 + p->num_objects * (20/4) + nr;
return data_crc != ntohl(*index_crc);
}
static void copy_pack_data(struct sha1file *f,
struct packed_git *p,
struct pack_window **w_curs,
off_t offset,
off_t len)
{
unsigned char *in;
unsigned int avail;
while (len) {
in = use_pack(p, w_curs, offset, &avail);
if (avail > len)
avail = (unsigned int)len;
sha1write(f, in, avail);
offset += avail;
len -= avail;
}
}
static unsigned long write_object(struct sha1file *f,
struct object_entry *entry)
{
unsigned long size;
enum object_type type;
void *buf;
unsigned char header[10];
unsigned hdrlen;
off_t datalen;
enum object_type obj_type;
int to_reuse = 0;
if (!pack_to_stdout)
crc32_begin(f);
obj_type = entry->type;
if (no_reuse_object)
to_reuse = 0; /* explicit */
else if (!entry->in_pack)
to_reuse = 0; /* can't reuse what we don't have */
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 */
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 = (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.
*/
hdrlen = encode_header(obj_type, size, header);
sha1write(f, header, hdrlen);
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.
*/
off_t 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, pack_compression_level);
free(buf);
}
else {
struct packed_git *p = entry->in_pack;
struct pack_window *w_curs = NULL;
struct revindex_entry *revidx;
off_t 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) {
off_t 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;
}
offset = entry->in_pack_offset;
revidx = find_packed_object(p, offset);
datalen = revidx[1].offset - offset;
if (!pack_to_stdout && p->index_version > 1 &&
check_pack_crc(p, &w_curs, offset, datalen, revidx->nr))
die("bad packed object CRC for %s", sha1_to_hex(entry->sha1));
offset += entry->in_pack_header_size;
datalen -= entry->in_pack_header_size;
if (!pack_to_stdout && p->index_version == 1 &&
check_pack_inflate(p, &w_curs, offset, datalen, entry->size))
die("corrupt packed object for %s", sha1_to_hex(entry->sha1));
copy_pack_data(f, p, &w_curs, offset, datalen);
unuse_pack(&w_curs);
reused++;
}
if (entry->delta)
written_delta++;
written++;
if (!pack_to_stdout)
entry->crc32 = crc32_end(f);
return hdrlen + datalen;
}
static off_t write_one(struct sha1file *f,
struct object_entry *e,
off_t offset)
{
unsigned long size;
/* offset is non zero if object is written already. */
if (e->offset || e->preferred_base)
return offset;
/* if we are deltified, write out base object first. */
if (e->delta)
offset = write_one(f, e->delta, offset);
e->offset = offset;
size = write_object(f, e);
/* make sure off_t is sufficiently large not to wrap */
if (offset > offset + size)
die("pack too large for current definition of off_t");
return offset + size;
}
static int open_object_dir_tmp(const char *path)
{
snprintf(tmpname, sizeof(tmpname), "%s/%s", get_object_directory(), path);
return mkstemp(tmpname);
}
static off_t write_pack_file(void)
{
uint32_t i;
struct sha1file *f;
off_t offset, last_obj_offset = 0;
struct pack_header hdr;
int do_progress = progress;
if (pack_to_stdout) {
f = sha1fd(1, "<stdout>");
do_progress >>= 1;
} else {
int fd = open_object_dir_tmp("tmp_pack_XXXXXX");
if (fd < 0)
die("unable to create %s: %s\n", tmpname, strerror(errno));
pack_tmp_name = xstrdup(tmpname);
f = sha1fd(fd, pack_tmp_name);
}
if (do_progress)
start_progress(&progress_state, "Writing %u objects...", "", 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++) {
last_obj_offset = offset;
offset = write_one(f, objects + i, offset);
if (do_progress)
display_progress(&progress_state, written);
}
if (do_progress)
stop_progress(&progress_state);
done:
if (written != nr_result)
die("wrote %u objects while expecting %u", written, nr_result);
sha1close(f, pack_file_sha1, 1);
return last_obj_offset;
}
static int sha1_sort(const void *_a, const void *_b)
{
const struct object_entry *a = *(struct object_entry **)_a;
const struct object_entry *b = *(struct object_entry **)_b;
return hashcmp(a->sha1, b->sha1);
}
static uint32_t index_default_version = 1;
static uint32_t index_off32_limit = 0x7fffffff;
static void write_index_file(off_t last_obj_offset, unsigned char *sha1)
{
struct sha1file *f;
struct object_entry **sorted_by_sha, **list, **last;
uint32_t array[256];
uint32_t i, index_version;
SHA_CTX ctx;
int fd = open_object_dir_tmp("tmp_idx_XXXXXX");
if (fd < 0)
die("unable to create %s: %s\n", tmpname, strerror(errno));
idx_tmp_name = xstrdup(tmpname);
f = sha1fd(fd, idx_tmp_name);
if (nr_result) {
uint32_t j = 0;
sorted_by_sha =
xcalloc(nr_result, sizeof(struct object_entry *));
for (i = 0; i < nr_objects; i++)
if (!objects[i].preferred_base)
sorted_by_sha[j++] = objects + i;
if (j != nr_result)
die("listed %u objects while expecting %u", j, nr_result);
qsort(sorted_by_sha, nr_result, sizeof(*sorted_by_sha), sha1_sort);
list = sorted_by_sha;
last = sorted_by_sha + nr_result;
} else
sorted_by_sha = list = last = NULL;
/* if last object's offset is >= 2^31 we should use index V2 */
index_version = (last_obj_offset >> 31) ? 2 : index_default_version;
/* index versions 2 and above need a header */
if (index_version >= 2) {
struct pack_idx_header hdr;
hdr.idx_signature = htonl(PACK_IDX_SIGNATURE);
hdr.idx_version = htonl(index_version);
sha1write(f, &hdr, sizeof(hdr));
}
/*
* 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 * 4);
/* Compute the SHA1 hash of sorted object names. */
SHA1_Init(&ctx);
/* Write the actual SHA1 entries. */
list = sorted_by_sha;
for (i = 0; i < nr_result; i++) {
struct object_entry *entry = *list++;
if (index_version < 2) {
uint32_t offset = htonl(entry->offset);
sha1write(f, &offset, 4);
}
sha1write(f, entry->sha1, 20);
SHA1_Update(&ctx, entry->sha1, 20);
}
if (index_version >= 2) {
unsigned int nr_large_offset = 0;
/* write the crc32 table */
list = sorted_by_sha;
for (i = 0; i < nr_objects; i++) {
struct object_entry *entry = *list++;
uint32_t crc32_val = htonl(entry->crc32);
sha1write(f, &crc32_val, 4);
}
/* write the 32-bit offset table */
list = sorted_by_sha;
for (i = 0; i < nr_objects; i++) {
struct object_entry *entry = *list++;
uint32_t offset = (entry->offset <= index_off32_limit) ?
entry->offset : (0x80000000 | nr_large_offset++);
offset = htonl(offset);
sha1write(f, &offset, 4);
}
/* write the large offset table */
list = sorted_by_sha;
while (nr_large_offset) {
struct object_entry *entry = *list++;
uint64_t offset = entry->offset;
if (offset > index_off32_limit) {
uint32_t split[2];
split[0] = htonl(offset >> 32);
split[1] = htonl(offset & 0xffffffff);
sha1write(f, split, 8);
nr_large_offset--;
}
}
}
sha1write(f, pack_file_sha1, 20);
sha1close(f, NULL, 1);
free(sorted_by_sha);
SHA1_Final(sha1, &ctx);
}
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 (!hashcmp(sha1, objects[object_ix[i] - 1].sha1))
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)
{
uint32_t 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, enum object_type type,
unsigned hash, int exclude)
{
struct object_entry *entry;
struct packed_git *p, *found_pack = NULL;
off_t found_offset = 0;
int ix;
ix = nr_objects ? locate_object_entry_hash(sha1) : -1;
if (ix >= 0) {
if (exclude) {
entry = objects + object_ix[ix] - 1;
if (!entry->preferred_base)
nr_result--;
entry->preferred_base = 1;
}
return 0;
}
for (p = packed_git; p; p = p->next) {
off_t offset = find_pack_entry_one(sha1, p);
if (offset) {
if (!found_pack) {
found_offset = offset;
found_pack = p;
}
if (exclude)
break;
if (incremental)
return 0;
if (local && !p->pack_local)
return 0;
}
}
if (nr_objects >= nr_alloc) {
nr_alloc = (nr_alloc + 1024) * 3 / 2;
objects = xrealloc(objects, nr_alloc * sizeof(*entry));
}
entry = objects + nr_objects++;
memset(entry, 0, sizeof(*entry));
hashcpy(entry->sha1, sha1);
entry->hash = hash;
if (type)
entry->type = type;
if (exclude)
entry->preferred_base = 1;
else
nr_result++;
if (found_pack) {
entry->in_pack = found_pack;
entry->in_pack_offset = found_offset;
}
if (object_ix_hashsz * 3 <= nr_objects * 4)
rehash_objects();
else
object_ix[-1 - ix] = nr_objects;
if (progress)
display_progress(&progress_state, nr_objects);
return 1;
}
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;
enum object_type type;
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 && !hashcmp(ent->sha1, sha1)) {
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 (type != OBJ_TREE) {
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;
}
hashcpy(nent->sha1, sha1);
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;
int cmp;
while (tree_entry(tree,&entry)) {
cmp = tree_entry_len(entry.path, entry.sha1) != cmplen ? 1 :
memcmp(name, entry.path, cmplen);
if (cmp > 0)
continue;
if (cmp < 0)
return;
if (name[cmplen] != '/') {
unsigned hash = name_hash(fullname);
add_object_entry(entry.sha1,
S_ISDIR(entry.mode) ? OBJ_TREE : OBJ_BLOB,
hash, 1);
return;
}
if (S_ISDIR(entry.mode)) {
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;
init_tree_desc(&sub, tree->tree_data, 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(const char *name, unsigned hash)
{
struct pbase_tree *it;
int cmplen;
if (!num_preferred_base || check_pbase_path(hash))
return;
cmplen = name_cmp_len(name);
for (it = pbase_tree; it; it = it->next) {
if (cmplen == 0) {
add_object_entry(it->pcache.sha1, OBJ_TREE, 0, 1);
}
else {
struct tree_desc tree;
init_tree_desc(&tree, it->pcache.tree_data, 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];
if (window <= num_preferred_base++)
return;
data = read_object_with_reference(sha1, tree_type, &size, tree_sha1);
if (!data)
return;
for (it = pbase_tree; it; it = it->next) {
if (!hashcmp(it->pcache.sha1, tree_sha1)) {
free(data);
return;
}
}
it = xcalloc(1, sizeof(*it));
it->next = pbase_tree;
pbase_tree = it;
hashcpy(it->pcache.sha1, tree_sha1);
it->pcache.tree_data = data;
it->pcache.tree_size = size;
}
static void check_object(struct object_entry *entry)
{
if (entry->in_pack) {
struct packed_git *p = entry->in_pack;
struct pack_window *w_curs = NULL;
const unsigned char *base_ref = NULL;
struct object_entry *base_entry;
unsigned long used, used_0;
unsigned int avail;
off_t ofs;
unsigned char *buf, c;
buf = use_pack(p, &w_curs, entry->in_pack_offset, &avail);
/*
* We want in_pack_type even if we do not reuse delta
* since non-delta representations could still be reused.
*/
used = unpack_object_header_gently(buf, avail,
&entry->in_pack_type,
&entry->size);
/*
* Determine if this is a delta and if so whether we can
* reuse it or not. Otherwise let's find out as cheaply as
* possible what the actual type and size for this object is.
*/
switch (entry->in_pack_type) {
default:
/* Not a delta hence we've already got all we need. */
entry->type = entry->in_pack_type;
entry->in_pack_header_size = used;
unuse_pack(&w_curs);
return;
case OBJ_REF_DELTA:
if (!no_reuse_delta && !entry->preferred_base)
base_ref = use_pack(p, &w_curs,
entry->in_pack_offset + used, NULL);
entry->in_pack_header_size = used + 20;
break;
case OBJ_OFS_DELTA:
buf = use_pack(p, &w_curs,
entry->in_pack_offset + used, NULL);
used_0 = 0;
c = buf[used_0++];
ofs = c & 127;
while (c & 128) {
ofs += 1;
if (!ofs || MSB(ofs, 7))
die("delta base offset overflow in pack for %s",
sha1_to_hex(entry->sha1));
c = buf[used_0++];
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;
if (!no_reuse_delta && !entry->preferred_base)
base_ref = find_packed_object_name(p, ofs);
entry->in_pack_header_size = used + used_0;
break;
}
if (base_ref && (base_entry = locate_object_entry(base_ref))) {
/*
* If base_ref was set above that means we wish to
* reuse delta data, and we even found that base
* in the list of objects we want to pack. Goodie!
*
* 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->type = entry->in_pack_type;
entry->delta = base_entry;
entry->delta_sibling = base_entry->delta_child;
base_entry->delta_child = entry;
unuse_pack(&w_curs);
return;
}
if (entry->type) {
/*
* This must be a delta and we already know what the
* final object type is. Let's extract the actual
* object size from the delta header.
*/
entry->size = get_size_from_delta(p, &w_curs,
entry->in_pack_offset + entry->in_pack_header_size);
unuse_pack(&w_curs);
return;
}
/*
* No choice but to fall back to the recursive delta walk
* with sha1_object_info() to find about the object type
* at this point...
*/
unuse_pack(&w_curs);
}
entry->type = sha1_object_info(entry->sha1, &entry->size);
if (entry->type < 0)
die("unable to get type of object %s",
sha1_to_hex(entry->sha1));
}
static int pack_offset_sort(const void *_a, const void *_b)
{
const struct object_entry *a = *(struct object_entry **)_a;
const struct object_entry *b = *(struct object_entry **)_b;
/* avoid filesystem trashing with loose objects */
if (!a->in_pack && !b->in_pack)
return hashcmp(a->sha1, b->sha1);
if (a->in_pack < b->in_pack)
return -1;
if (a->in_pack > b->in_pack)
return 1;
return a->in_pack_offset < b->in_pack_offset ? -1 :
(a->in_pack_offset > b->in_pack_offset);
}
static void get_object_details(void)
{
uint32_t i;
struct object_entry **sorted_by_offset;
sorted_by_offset = xcalloc(nr_objects, sizeof(struct object_entry *));
for (i = 0; i < nr_objects; i++)
sorted_by_offset[i] = objects + i;
qsort(sorted_by_offset, nr_objects, sizeof(*sorted_by_offset), pack_offset_sort);
prepare_pack_ix();
for (i = 0; i < nr_objects; i++)
check_object(sorted_by_offset[i]);
free(sorted_by_offset);
}
static int type_size_sort(const void *_a, const void *_b)
{
const struct object_entry *a = *(struct object_entry **)_a;
const struct object_entry *b = *(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); /* newest last */
}
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;
enum object_type type;
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 &&
trg_entry->in_pack_type != OBJ_REF_DELTA &&
trg_entry->in_pack_type != OBJ_OFS_DELTA)
return 0;
/* Let's not bust the allowed depth. */
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 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 find_deltas(struct object_entry **list, int window, int depth)
{
uint32_t i = nr_objects, idx = 0, processed = 0;
unsigned int array_size = window * sizeof(struct unpacked);
struct unpacked *array;
int max_depth;
if (!nr_objects)
return;
array = xmalloc(array_size);
memset(array, 0, array_size);
if (progress)
start_progress(&progress_state, "Deltifying %u objects...", "", nr_result);
do {
struct object_entry *entry = list[--i];
struct unpacked *n = array + idx;
int j;
if (!entry->preferred_base)
processed++;
if (progress)
display_progress(&progress_state, processed);
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;
/*
* 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.
*/
max_depth = depth;
if (entry->delta_child) {
max_depth -= check_delta_limit(entry, 0);
if (max_depth <= 0)
goto next;
}
j = window;
while (--j > 0) {
uint32_t 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, max_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;
next:
idx++;
if (idx >= window)
idx = 0;
} while (i > 0);
if (progress)
stop_progress(&progress_state);
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)
{
struct object_entry **delta_list;
uint32_t i;
get_object_details();
if (!window || !depth)
return;
delta_list = xmalloc(nr_objects * sizeof(*delta_list));
for (i = 0; i < nr_objects; i++)
delta_list[i] = objects + i;
qsort(delta_list, nr_objects, sizeof(*delta_list), type_size_sort);
find_deltas(delta_list, window+1, depth);
free(delta_list);
}
static int git_pack_config(const char *k, const char *v)
{
if(!strcmp(k, "pack.window")) {
window = git_config_int(k, v);
return 0;
}
if(!strcmp(k, "pack.depth")) {
depth = git_config_int(k, v);
return 0;
}
if (!strcmp(k, "pack.compression")) {
int level = git_config_int(k, v);
if (level == -1)
level = Z_DEFAULT_COMPRESSION;
else if (level < 0 || level > Z_BEST_COMPRESSION)
die("bad pack compression level %d", level);
pack_compression_level = level;
pack_compression_seen = 1;
return 0;
}
return git_default_config(k, v);
}
static void read_object_list_from_stdin(void)
{
char line[40 + 1 + PATH_MAX + 2];
unsigned char sha1[20];
unsigned hash;
for (;;) {
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);
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, 0, hash, 0);
}
}
static void show_commit(struct commit *commit)
{
add_object_entry(commit->object.sha1, OBJ_COMMIT, 0, 0);
}
static void show_object(struct object_array_entry *p)
{
unsigned hash = name_hash(p->name);
add_preferred_base_object(p->name, hash);
add_object_entry(p->item->sha1, p->item->type, hash, 0);
}
static void show_edge(struct commit *commit)
{
add_preferred_base(commit->object.sha1);
}
static void get_object_list(int ac, const char **av)
{
struct rev_info revs;
char line[1000];
int flags = 0;
init_revisions(&revs, NULL);
save_commit_buffer = 0;
track_object_refs = 0;
setup_revisions(ac, av, &revs, NULL);
while (fgets(line, sizeof(line), stdin) != NULL) {
int len = strlen(line);
if (line[len - 1] == '\n')
line[--len] = 0;
if (!len)
break;
if (*line == '-') {
if (!strcmp(line, "--not")) {
flags ^= UNINTERESTING;
continue;
}
die("not a rev '%s'", line);
}
if (handle_revision_arg(line, &revs, flags, 1))
die("bad revision '%s'", line);
}
prepare_revision_walk(&revs);
mark_edges_uninteresting(revs.commits, &revs, show_edge);
traverse_commit_list(&revs, show_commit, show_object);
}
static int adjust_perm(const char *path, mode_t mode)
{
if (chmod(path, mode))
return -1;
return adjust_shared_perm(path);
}
int cmd_pack_objects(int argc, const char **argv, const char *prefix)
{
int use_internal_rev_list = 0;
int thin = 0;
uint32_t i;
off_t last_obj_offset;
const char *base_name = NULL;
const char **rp_av;
int rp_ac_alloc = 64;
int rp_ac;
rp_av = xcalloc(rp_ac_alloc, sizeof(*rp_av));
rp_av[0] = "pack-objects";
rp_av[1] = "--objects"; /* --thin will make it --objects-edge */
rp_ac = 2;
git_config(git_pack_config);
if (!pack_compression_seen && core_compression_seen)
pack_compression_level = core_compression_level;
progress = isatty(2);
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
if (*arg != '-')
break;
if (!strcmp("--non-empty", arg)) {
non_empty = 1;
continue;
}
if (!strcmp("--local", arg)) {
local = 1;
continue;
}
if (!strcmp("--incremental", arg)) {
incremental = 1;
continue;
}
if (!prefixcmp(arg, "--compression=")) {
char *end;
int level = strtoul(arg+14, &end, 0);
if (!arg[14] || *end)
usage(pack_usage);
if (level == -1)
level = Z_DEFAULT_COMPRESSION;
else if (level < 0 || level > Z_BEST_COMPRESSION)
die("bad pack compression level %d", level);
pack_compression_level = level;
continue;
}
if (!prefixcmp(arg, "--window=")) {
char *end;
window = strtoul(arg+9, &end, 0);
if (!arg[9] || *end)
usage(pack_usage);
continue;
}
if (!prefixcmp(arg, "--depth=")) {
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("--all-progress", arg)) {
progress = 2;
continue;
}
if (!strcmp("-q", arg)) {
progress = 0;
continue;
}
if (!strcmp("--no-reuse-delta", arg)) {
no_reuse_delta = 1;
continue;
}
if (!strcmp("--no-reuse-object", arg)) {
no_reuse_object = 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;
}
if (!strcmp("--revs", arg)) {
use_internal_rev_list = 1;
continue;
}
if (!strcmp("--unpacked", arg) ||
!prefixcmp(arg, "--unpacked=") ||
!strcmp("--reflog", arg) ||
!strcmp("--all", arg)) {
use_internal_rev_list = 1;
if (rp_ac >= rp_ac_alloc - 1) {
rp_ac_alloc = alloc_nr(rp_ac_alloc);
rp_av = xrealloc(rp_av,
rp_ac_alloc * sizeof(*rp_av));
}
rp_av[rp_ac++] = arg;
continue;
}
if (!strcmp("--thin", arg)) {
use_internal_rev_list = 1;
thin = 1;
rp_av[1] = "--objects-edge";
continue;
}
if (!prefixcmp(arg, "--index-version=")) {
char *c;
index_default_version = strtoul(arg + 16, &c, 10);
if (index_default_version > 2)
die("bad %s", arg);
if (*c == ',')
index_off32_limit = strtoul(c+1, &c, 0);
if (*c || index_off32_limit & 0x80000000)
die("bad %s", arg);
continue;
}
usage(pack_usage);
}
/* Traditionally "pack-objects [options] base extra" failed;
* we would however want to take refs parameter that would
* have been given to upstream rev-list ourselves, which means
* we somehow want to say what the base name is. So the
* syntax would be:
*
* pack-objects [options] base <refs...>
*
* in other words, we would treat the first non-option as the
* base_name and send everything else to the internal revision
* walker.
*/
if (!pack_to_stdout)
base_name = argv[i++];
if (pack_to_stdout != !base_name)
usage(pack_usage);
if (!pack_to_stdout && thin)
die("--thin cannot be used to build an indexable pack.");
prepare_packed_git();
if (progress)
start_progress(&progress_state, "Generating pack...",
"Counting objects: ", 0);
if (!use_internal_rev_list)
read_object_list_from_stdin();
else {
rp_av[rp_ac] = NULL;
get_object_list(rp_ac, rp_av);
}
if (progress) {
stop_progress(&progress_state);
fprintf(stderr, "Done counting %u objects.\n", nr_objects);
}
if (non_empty && !nr_result)
return 0;
if (progress && (nr_objects != nr_result))
fprintf(stderr, "Result has %u objects.\n", nr_result);
if (nr_result)
prepare_pack(window, depth);
last_obj_offset = write_pack_file();
if (!pack_to_stdout) {
unsigned char object_list_sha1[20];
mode_t mode = umask(0);
umask(mode);
mode = 0444 & ~mode;
write_index_file(last_obj_offset, object_list_sha1);
snprintf(tmpname, sizeof(tmpname), "%s-%s.pack",
base_name, sha1_to_hex(object_list_sha1));
if (adjust_perm(pack_tmp_name, mode))
die("unable to make temporary pack file readable: %s",
strerror(errno));
if (rename(pack_tmp_name, tmpname))
die("unable to rename temporary pack file: %s",
strerror(errno));
snprintf(tmpname, sizeof(tmpname), "%s-%s.idx",
base_name, sha1_to_hex(object_list_sha1));
if (adjust_perm(idx_tmp_name, mode))
die("unable to make temporary index file readable: %s",
strerror(errno));
if (rename(idx_tmp_name, tmpname))
die("unable to rename temporary index file: %s",
strerror(errno));
puts(sha1_to_hex(object_list_sha1));
}
if (progress)
fprintf(stderr, "Total %u (delta %u), reused %u (delta %u)\n",
written, written_delta, reused, reused_delta);
return 0;
}