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git-commit-vandalism/sha1_file.c
Junio C Hamano 3f9ac8d259 pack-objects: reuse data from existing packs. 
When generating a new pack, notice if we have already needed
objects in existing packs.  If an object is stored deltified,
and its base object is also what we are going to pack, then
reuse the existing deltified representation unconditionally,
bypassing all the expensive find_deltas() and try_deltas()
calls.

Also, notice if what we are going to write out exactly match
what is already in an existing pack (either deltified or just
compressed).  In such a case, we can just copy it instead of
going through the usual uncompressing & recompressing cycle.

Without this patch, in linux-2.6 repository with about 1500
loose objects and a single mega pack:

    $ git-rev-list --objects v2.6.16-rc3 >RL
    $ wc -l RL
    184141 RL
    $ time git-pack-objects p <RL
    Generating pack...
    Done counting 184141 objects.
    Packing 184141 objects....................
    a1fc7b3e537fcb9b3c46b7505df859f0a11e79d2

    real    12m4.323s
    user    11m2.560s
    sys     0m55.950s

With this patch, the same input:

    $ time ../git.junio/git-pack-objects q <RL
    Generating pack...
    Done counting 184141 objects.
    Packing 184141 objects.....................
    a1fc7b3e537fcb9b3c46b7505df859f0a11e79d2
    Total 184141, written 184141, reused 182441

    real    1m2.608s
    user    0m55.090s
    sys     0m1.830s

Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-02-22 13:14:56 -08:00

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/*
* GIT - The information manager from hell
*
* Copyright (C) Linus Torvalds, 2005
*
* This handles basic git sha1 object files - packing, unpacking,
* creation etc.
*/
#include "cache.h"
#include "delta.h"
#include "pack.h"
#ifndef O_NOATIME
#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
#define O_NOATIME 01000000
#else
#define O_NOATIME 0
#endif
#endif
const unsigned char null_sha1[20] = { 0, };
static unsigned int sha1_file_open_flag = O_NOATIME;
static unsigned hexval(char c)
{
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'a' && c <= 'f')
return c - 'a' + 10;
if (c >= 'A' && c <= 'F')
return c - 'A' + 10;
return ~0;
}
int get_sha1_hex(const char *hex, unsigned char *sha1)
{
int i;
for (i = 0; i < 20; i++) {
unsigned int val = (hexval(hex[0]) << 4) | hexval(hex[1]);
if (val & ~0xff)
return -1;
*sha1++ = val;
hex += 2;
}
return 0;
}
int adjust_shared_perm(const char *path)
{
struct stat st;
int mode;
if (!shared_repository)
return 0;
if (lstat(path, &st) < 0)
return -1;
mode = st.st_mode;
if (mode & S_IRUSR)
mode |= S_IRGRP;
if (mode & S_IWUSR)
mode |= S_IWGRP;
if (mode & S_IXUSR)
mode |= S_IXGRP;
if (S_ISDIR(mode))
mode |= S_ISGID;
if (chmod(path, mode) < 0)
return -2;
return 0;
}
int safe_create_leading_directories(char *path)
{
char *pos = path;
struct stat st;
if (*pos == '/')
pos++;
while (pos) {
pos = strchr(pos, '/');
if (!pos)
break;
*pos = 0;
if (!stat(path, &st)) {
/* path exists */
if (!S_ISDIR(st.st_mode)) {
*pos = '/';
return -3;
}
}
else if (mkdir(path, 0777)) {
*pos = '/';
return -1;
}
else if (adjust_shared_perm(path)) {
*pos = '/';
return -2;
}
*pos++ = '/';
}
return 0;
}
char * sha1_to_hex(const unsigned char *sha1)
{
static char buffer[50];
static const char hex[] = "0123456789abcdef";
char *buf = buffer;
int i;
for (i = 0; i < 20; i++) {
unsigned int val = *sha1++;
*buf++ = hex[val >> 4];
*buf++ = hex[val & 0xf];
}
*buf = '\0';
return buffer;
}
static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
{
int i;
for (i = 0; i < 20; i++) {
static char hex[] = "0123456789abcdef";
unsigned int val = sha1[i];
char *pos = pathbuf + i*2 + (i > 0);
*pos++ = hex[val >> 4];
*pos = hex[val & 0xf];
}
}
/*
* NOTE! This returns a statically allocated buffer, so you have to be
* careful about using it. Do a "strdup()" if you need to save the
* filename.
*
* Also note that this returns the location for creating. Reading
* SHA1 file can happen from any alternate directory listed in the
* DB_ENVIRONMENT environment variable if it is not found in
* the primary object database.
*/
char *sha1_file_name(const unsigned char *sha1)
{
static char *name, *base;
if (!base) {
const char *sha1_file_directory = get_object_directory();
int len = strlen(sha1_file_directory);
base = xmalloc(len + 60);
memcpy(base, sha1_file_directory, len);
memset(base+len, 0, 60);
base[len] = '/';
base[len+3] = '/';
name = base + len + 1;
}
fill_sha1_path(name, sha1);
return base;
}
char *sha1_pack_name(const unsigned char *sha1)
{
static const char hex[] = "0123456789abcdef";
static char *name, *base, *buf;
int i;
if (!base) {
const char *sha1_file_directory = get_object_directory();
int len = strlen(sha1_file_directory);
base = xmalloc(len + 60);
sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.pack", sha1_file_directory);
name = base + len + 11;
}
buf = name;
for (i = 0; i < 20; i++) {
unsigned int val = *sha1++;
*buf++ = hex[val >> 4];
*buf++ = hex[val & 0xf];
}
return base;
}
char *sha1_pack_index_name(const unsigned char *sha1)
{
static const char hex[] = "0123456789abcdef";
static char *name, *base, *buf;
int i;
if (!base) {
const char *sha1_file_directory = get_object_directory();
int len = strlen(sha1_file_directory);
base = xmalloc(len + 60);
sprintf(base, "%s/pack/pack-1234567890123456789012345678901234567890.idx", sha1_file_directory);
name = base + len + 11;
}
buf = name;
for (i = 0; i < 20; i++) {
unsigned int val = *sha1++;
*buf++ = hex[val >> 4];
*buf++ = hex[val & 0xf];
}
return base;
}
struct alternate_object_database *alt_odb_list;
static struct alternate_object_database **alt_odb_tail;
/*
* Prepare alternate object database registry.
*
* The variable alt_odb_list points at the list of struct
* alternate_object_database. The elements on this list come from
* non-empty elements from colon separated ALTERNATE_DB_ENVIRONMENT
* environment variable, and $GIT_OBJECT_DIRECTORY/info/alternates,
* whose contents is similar to that environment variable but can be
* LF separated. Its base points at a statically allocated buffer that
* contains "/the/directory/corresponding/to/.git/objects/...", while
* its name points just after the slash at the end of ".git/objects/"
* in the example above, and has enough space to hold 40-byte hex
* SHA1, an extra slash for the first level indirection, and the
* terminating NUL.
*/
static void link_alt_odb_entries(const char *alt, const char *ep, int sep,
const char *relative_base)
{
const char *cp, *last;
struct alternate_object_database *ent;
const char *objdir = get_object_directory();
int base_len = -1;
last = alt;
while (last < ep) {
cp = last;
if (cp < ep && *cp == '#') {
while (cp < ep && *cp != sep)
cp++;
last = cp + 1;
continue;
}
for ( ; cp < ep && *cp != sep; cp++)
;
if (last != cp) {
struct stat st;
struct alternate_object_database *alt;
/* 43 = 40-byte + 2 '/' + terminating NUL */
int pfxlen = cp - last;
int entlen = pfxlen + 43;
if (*last != '/' && relative_base) {
/* Relative alt-odb */
if (base_len < 0)
base_len = strlen(relative_base) + 1;
entlen += base_len;
pfxlen += base_len;
}
ent = xmalloc(sizeof(*ent) + entlen);
if (*last != '/' && relative_base) {
memcpy(ent->base, relative_base, base_len - 1);
ent->base[base_len - 1] = '/';
memcpy(ent->base + base_len,
last, cp - last);
}
else
memcpy(ent->base, last, pfxlen);
ent->name = ent->base + pfxlen + 1;
ent->base[pfxlen + 3] = '/';
ent->base[pfxlen] = ent->base[entlen-1] = 0;
/* Detect cases where alternate disappeared */
if (stat(ent->base, &st) || !S_ISDIR(st.st_mode)) {
error("object directory %s does not exist; "
"check .git/objects/info/alternates.",
ent->base);
goto bad;
}
ent->base[pfxlen] = '/';
/* Prevent the common mistake of listing the same
* thing twice, or object directory itself.
*/
for (alt = alt_odb_list; alt; alt = alt->next)
if (!memcmp(ent->base, alt->base, pfxlen))
goto bad;
if (!memcmp(ent->base, objdir, pfxlen)) {
bad:
free(ent);
}
else {
*alt_odb_tail = ent;
alt_odb_tail = &(ent->next);
ent->next = NULL;
}
}
while (cp < ep && *cp == sep)
cp++;
last = cp;
}
}
void prepare_alt_odb(void)
{
char path[PATH_MAX];
char *map;
int fd;
struct stat st;
char *alt;
alt = getenv(ALTERNATE_DB_ENVIRONMENT);
if (!alt) alt = "";
if (alt_odb_tail)
return;
alt_odb_tail = &alt_odb_list;
link_alt_odb_entries(alt, alt + strlen(alt), ':', NULL);
sprintf(path, "%s/info/alternates", get_object_directory());
fd = open(path, O_RDONLY);
if (fd < 0)
return;
if (fstat(fd, &st) || (st.st_size == 0)) {
close(fd);
return;
}
map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (map == MAP_FAILED)
return;
link_alt_odb_entries(map, map + st.st_size, '\n',
get_object_directory());
munmap(map, st.st_size);
}
static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
{
char *name = sha1_file_name(sha1);
struct alternate_object_database *alt;
if (!stat(name, st))
return name;
prepare_alt_odb();
for (alt = alt_odb_list; alt; alt = alt->next) {
name = alt->name;
fill_sha1_path(name, sha1);
if (!stat(alt->base, st))
return alt->base;
}
return NULL;
}
#define PACK_MAX_SZ (1<<26)
static int pack_used_ctr;
static unsigned long pack_mapped;
struct packed_git *packed_git;
static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
void **idx_map_)
{
void *idx_map;
unsigned int *index;
unsigned long idx_size;
int nr, i;
int fd = open(path, O_RDONLY);
struct stat st;
if (fd < 0)
return -1;
if (fstat(fd, &st)) {
close(fd);
return -1;
}
idx_size = st.st_size;
idx_map = mmap(NULL, idx_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (idx_map == MAP_FAILED)
return -1;
index = idx_map;
*idx_map_ = idx_map;
*idx_size_ = idx_size;
/* check index map */
if (idx_size < 4*256 + 20 + 20)
return error("index file too small");
nr = 0;
for (i = 0; i < 256; i++) {
unsigned int n = ntohl(index[i]);
if (n < nr)
return error("non-monotonic index");
nr = n;
}
/*
* Total size:
* - 256 index entries 4 bytes each
* - 24-byte entries * nr (20-byte sha1 + 4-byte offset)
* - 20-byte SHA1 of the packfile
* - 20-byte SHA1 file checksum
*/
if (idx_size != 4*256 + nr * 24 + 20 + 20)
return error("wrong index file size");
return 0;
}
static int unuse_one_packed_git(void)
{
struct packed_git *p, *lru = NULL;
for (p = packed_git; p; p = p->next) {
if (p->pack_use_cnt || !p->pack_base)
continue;
if (!lru || p->pack_last_used < lru->pack_last_used)
lru = p;
}
if (!lru)
return 0;
munmap(lru->pack_base, lru->pack_size);
lru->pack_base = NULL;
return 1;
}
void unuse_packed_git(struct packed_git *p)
{
p->pack_use_cnt--;
}
int use_packed_git(struct packed_git *p)
{
if (!p->pack_size) {
struct stat st;
// We created the struct before we had the pack
stat(p->pack_name, &st);
if (!S_ISREG(st.st_mode))
die("packfile %s not a regular file", p->pack_name);
p->pack_size = st.st_size;
}
if (!p->pack_base) {
int fd;
struct stat st;
void *map;
pack_mapped += p->pack_size;
while (PACK_MAX_SZ < pack_mapped && unuse_one_packed_git())
; /* nothing */
fd = open(p->pack_name, O_RDONLY);
if (fd < 0)
die("packfile %s cannot be opened", p->pack_name);
if (fstat(fd, &st)) {
close(fd);
die("packfile %s cannot be opened", p->pack_name);
}
if (st.st_size != p->pack_size)
die("packfile %s size mismatch.", p->pack_name);
map = mmap(NULL, p->pack_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (map == MAP_FAILED)
die("packfile %s cannot be mapped.", p->pack_name);
p->pack_base = map;
/* Check if the pack file matches with the index file.
* this is cheap.
*/
if (memcmp((char*)(p->index_base) + p->index_size - 40,
p->pack_base + p->pack_size - 20, 20)) {
die("packfile %s does not match index.", p->pack_name);
}
}
p->pack_last_used = pack_used_ctr++;
p->pack_use_cnt++;
return 0;
}
struct packed_git *add_packed_git(char *path, int path_len, int local)
{
struct stat st;
struct packed_git *p;
unsigned long idx_size;
void *idx_map;
unsigned char sha1[20];
if (check_packed_git_idx(path, &idx_size, &idx_map))
return NULL;
/* do we have a corresponding .pack file? */
strcpy(path + path_len - 4, ".pack");
if (stat(path, &st) || !S_ISREG(st.st_mode)) {
munmap(idx_map, idx_size);
return NULL;
}
/* ok, it looks sane as far as we can check without
* actually mapping the pack file.
*/
p = xmalloc(sizeof(*p) + path_len + 2);
strcpy(p->pack_name, path);
p->index_size = idx_size;
p->pack_size = st.st_size;
p->index_base = idx_map;
p->next = NULL;
p->pack_base = NULL;
p->pack_last_used = 0;
p->pack_use_cnt = 0;
p->pack_local = local;
if ((path_len > 44) && !get_sha1_hex(path + path_len - 44, sha1))
memcpy(p->sha1, sha1, 20);
return p;
}
struct packed_git *parse_pack_index(unsigned char *sha1)
{
char *path = sha1_pack_index_name(sha1);
return parse_pack_index_file(sha1, path);
}
struct packed_git *parse_pack_index_file(const unsigned char *sha1, char *idx_path)
{
struct packed_git *p;
unsigned long idx_size;
void *idx_map;
char *path;
if (check_packed_git_idx(idx_path, &idx_size, &idx_map))
return NULL;
path = sha1_pack_name(sha1);
p = xmalloc(sizeof(*p) + strlen(path) + 2);
strcpy(p->pack_name, path);
p->index_size = idx_size;
p->pack_size = 0;
p->index_base = idx_map;
p->next = NULL;
p->pack_base = NULL;
p->pack_last_used = 0;
p->pack_use_cnt = 0;
memcpy(p->sha1, sha1, 20);
return p;
}
void install_packed_git(struct packed_git *pack)
{
pack->next = packed_git;
packed_git = pack;
}
static void prepare_packed_git_one(char *objdir, int local)
{
char path[PATH_MAX];
int len;
DIR *dir;
struct dirent *de;
sprintf(path, "%s/pack", objdir);
len = strlen(path);
dir = opendir(path);
if (!dir) {
if (errno != ENOENT)
error("unable to open object pack directory: %s: %s\n",
path, strerror(errno));
return;
}
path[len++] = '/';
while ((de = readdir(dir)) != NULL) {
int namelen = strlen(de->d_name);
struct packed_git *p;
if (strcmp(de->d_name + namelen - 4, ".idx"))
continue;
/* we have .idx. Is it a file we can map? */
strcpy(path + len, de->d_name);
p = add_packed_git(path, len + namelen, local);
if (!p)
continue;
p->next = packed_git;
packed_git = p;
}
closedir(dir);
}
void prepare_packed_git(void)
{
static int run_once = 0;
struct alternate_object_database *alt;
if (run_once)
return;
prepare_packed_git_one(get_object_directory(), 1);
prepare_alt_odb();
for (alt = alt_odb_list; alt; alt = alt->next) {
alt->name[-1] = 0;
prepare_packed_git_one(alt->base, 0);
alt->name[-1] = '/';
}
run_once = 1;
}
int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
{
char header[100];
unsigned char real_sha1[20];
SHA_CTX c;
SHA1_Init(&c);
SHA1_Update(&c, header, 1+sprintf(header, "%s %lu", type, size));
SHA1_Update(&c, map, size);
SHA1_Final(real_sha1, &c);
return memcmp(sha1, real_sha1, 20) ? -1 : 0;
}
static void *map_sha1_file_internal(const unsigned char *sha1,
unsigned long *size)
{
struct stat st;
void *map;
int fd;
char *filename = find_sha1_file(sha1, &st);
if (!filename) {
return NULL;
}
fd = open(filename, O_RDONLY | sha1_file_open_flag);
if (fd < 0) {
/* See if it works without O_NOATIME */
switch (sha1_file_open_flag) {
default:
fd = open(filename, O_RDONLY);
if (fd >= 0)
break;
/* Fallthrough */
case 0:
return NULL;
}
/* If it failed once, it will probably fail again.
* Stop using O_NOATIME
*/
sha1_file_open_flag = 0;
}
map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (map == MAP_FAILED)
return NULL;
*size = st.st_size;
return map;
}
int unpack_sha1_header(z_stream *stream, void *map, unsigned long mapsize, void *buffer, unsigned long size)
{
/* Get the data stream */
memset(stream, 0, sizeof(*stream));
stream->next_in = map;
stream->avail_in = mapsize;
stream->next_out = buffer;
stream->avail_out = size;
inflateInit(stream);
return inflate(stream, 0);
}
static void *unpack_sha1_rest(z_stream *stream, void *buffer, unsigned long size)
{
int bytes = strlen(buffer) + 1;
unsigned char *buf = xmalloc(1+size);
memcpy(buf, buffer + bytes, stream->total_out - bytes);
bytes = stream->total_out - bytes;
if (bytes < size) {
stream->next_out = buf + bytes;
stream->avail_out = size - bytes;
while (inflate(stream, Z_FINISH) == Z_OK)
/* nothing */;
}
buf[size] = 0;
inflateEnd(stream);
return buf;
}
/*
* We used to just use "sscanf()", but that's actually way
* too permissive for what we want to check. So do an anal
* object header parse by hand.
*/
int parse_sha1_header(char *hdr, char *type, unsigned long *sizep)
{
int i;
unsigned long size;
/*
* The type can be at most ten bytes (including the
* terminating '\0' that we add), and is followed by
* a space.
*/
i = 10;
for (;;) {
char c = *hdr++;
if (c == ' ')
break;
if (!--i)
return -1;
*type++ = c;
}
*type = 0;
/*
* The length must follow immediately, and be in canonical
* decimal format (ie "010" is not valid).
*/
size = *hdr++ - '0';
if (size > 9)
return -1;
if (size) {
for (;;) {
unsigned long c = *hdr - '0';
if (c > 9)
break;
hdr++;
size = size * 10 + c;
}
}
*sizep = size;
/*
* The length must be followed by a zero byte
*/
return *hdr ? -1 : 0;
}
void * unpack_sha1_file(void *map, unsigned long mapsize, char *type, unsigned long *size)
{
int ret;
z_stream stream;
char hdr[8192];
ret = unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr));
if (ret < Z_OK || parse_sha1_header(hdr, type, size) < 0)
return NULL;
return unpack_sha1_rest(&stream, hdr, *size);
}
/* forward declaration for a mutually recursive function */
static int packed_object_info(struct pack_entry *entry,
char *type, unsigned long *sizep);
static int packed_delta_info(unsigned char *base_sha1,
unsigned long delta_size,
unsigned long left,
char *type,
unsigned long *sizep,
struct packed_git *p)
{
struct pack_entry base_ent;
if (left < 20)
die("truncated pack file");
/* The base entry _must_ be in the same pack */
if (!find_pack_entry_one(base_sha1, &base_ent, p))
die("failed to find delta-pack base object %s",
sha1_to_hex(base_sha1));
/* We choose to only get the type of the base object and
* ignore potentially corrupt pack file that expects the delta
* based on a base with a wrong size. This saves tons of
* inflate() calls.
*/
if (packed_object_info(&base_ent, type, NULL))
die("cannot get info for delta-pack base");
if (sizep) {
const unsigned char *data;
unsigned char delta_head[64];
unsigned long result_size;
z_stream stream;
int st;
memset(&stream, 0, sizeof(stream));
data = stream.next_in = base_sha1 + 20;
stream.avail_in = left - 20;
stream.next_out = delta_head;
stream.avail_out = sizeof(delta_head);
inflateInit(&stream);
st = inflate(&stream, Z_FINISH);
inflateEnd(&stream);
if ((st != Z_STREAM_END) &&
stream.total_out != sizeof(delta_head))
die("delta data unpack-initial failed");
/* Examine the initial part of the delta to figure out
* the result size.
*/
data = delta_head;
get_delta_hdr_size(&data); /* ignore base size */
/* Read the result size */
result_size = get_delta_hdr_size(&data);
*sizep = result_size;
}
return 0;
}
static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
enum object_type *type, unsigned long *sizep)
{
unsigned shift;
unsigned char *pack, c;
unsigned long size;
if (offset >= p->pack_size)
die("object offset outside of pack file");
pack = p->pack_base + offset;
c = *pack++;
offset++;
*type = (c >> 4) & 7;
size = c & 15;
shift = 4;
while (c & 0x80) {
if (offset >= p->pack_size)
die("object offset outside of pack file");
c = *pack++;
offset++;
size += (c & 0x7f) << shift;
shift += 7;
}
*sizep = size;
return offset;
}
int check_reuse_pack_delta(struct packed_git *p, unsigned long offset,
unsigned char *base, unsigned long *sizep,
enum object_type *kindp)
{
unsigned long ptr;
int status = -1;
use_packed_git(p);
ptr = offset;
ptr = unpack_object_header(p, ptr, kindp, sizep);
if (*kindp != OBJ_DELTA)
goto done;
memcpy(base, p->pack_base + ptr, 20);
status = 0;
done:
unuse_packed_git(p);
return status;
}
void packed_object_info_detail(struct pack_entry *e,
char *type,
unsigned long *size,
unsigned long *store_size,
int *delta_chain_length,
unsigned char *base_sha1)
{
struct packed_git *p = e->p;
unsigned long offset, left;
unsigned char *pack;
enum object_type kind;
offset = unpack_object_header(p, e->offset, &kind, size);
pack = p->pack_base + offset;
left = p->pack_size - offset;
if (kind != OBJ_DELTA)
*delta_chain_length = 0;
else {
int chain_length = 0;
memcpy(base_sha1, pack, 20);
do {
struct pack_entry base_ent;
unsigned long junk;
find_pack_entry_one(pack, &base_ent, p);
offset = unpack_object_header(p, base_ent.offset,
&kind, &junk);
pack = p->pack_base + offset;
chain_length++;
} while (kind == OBJ_DELTA);
*delta_chain_length = chain_length;
}
switch (kind) {
case OBJ_COMMIT:
strcpy(type, "commit");
break;
case OBJ_TREE:
strcpy(type, "tree");
break;
case OBJ_BLOB:
strcpy(type, "blob");
break;
case OBJ_TAG:
strcpy(type, "tag");
break;
default:
die("corrupted pack file %s containing object of kind %d",
p->pack_name, kind);
}
*store_size = 0; /* notyet */
}
static int packed_object_info(struct pack_entry *entry,
char *type, unsigned long *sizep)
{
struct packed_git *p = entry->p;
unsigned long offset, size, left;
unsigned char *pack;
enum object_type kind;
int retval;
if (use_packed_git(p))
die("cannot map packed file");
offset = unpack_object_header(p, entry->offset, &kind, &size);
pack = p->pack_base + offset;
left = p->pack_size - offset;
switch (kind) {
case OBJ_DELTA:
retval = packed_delta_info(pack, size, left, type, sizep, p);
unuse_packed_git(p);
return retval;
case OBJ_COMMIT:
strcpy(type, "commit");
break;
case OBJ_TREE:
strcpy(type, "tree");
break;
case OBJ_BLOB:
strcpy(type, "blob");
break;
case OBJ_TAG:
strcpy(type, "tag");
break;
default:
die("corrupted pack file %s containing object of kind %d",
p->pack_name, kind);
}
if (sizep)
*sizep = size;
unuse_packed_git(p);
return 0;
}
/* forward declaration for a mutually recursive function */
static void *unpack_entry(struct pack_entry *, char *, unsigned long *);
static void *unpack_delta_entry(unsigned char *base_sha1,
unsigned long delta_size,
unsigned long left,
char *type,
unsigned long *sizep,
struct packed_git *p)
{
struct pack_entry base_ent;
void *data, *delta_data, *result, *base;
unsigned long data_size, result_size, base_size;
z_stream stream;
int st;
if (left < 20)
die("truncated pack file");
data = base_sha1 + 20;
data_size = left - 20;
delta_data = xmalloc(delta_size);
memset(&stream, 0, sizeof(stream));
stream.next_in = data;
stream.avail_in = data_size;
stream.next_out = delta_data;
stream.avail_out = delta_size;
inflateInit(&stream);
st = inflate(&stream, Z_FINISH);
inflateEnd(&stream);
if ((st != Z_STREAM_END) || stream.total_out != delta_size)
die("delta data unpack failed");
/* The base entry _must_ be in the same pack */
if (!find_pack_entry_one(base_sha1, &base_ent, p))
die("failed to find delta-pack base object %s",
sha1_to_hex(base_sha1));
base = unpack_entry_gently(&base_ent, type, &base_size);
if (!base)
die("failed to read delta-pack base object %s",
sha1_to_hex(base_sha1));
result = patch_delta(base, base_size,
delta_data, delta_size,
&result_size);
if (!result)
die("failed to apply delta");
free(delta_data);
free(base);
*sizep = result_size;
return result;
}
static void *unpack_non_delta_entry(unsigned char *data,
unsigned long size,
unsigned long left)
{
int st;
z_stream stream;
unsigned char *buffer;
buffer = xmalloc(size + 1);
buffer[size] = 0;
memset(&stream, 0, sizeof(stream));
stream.next_in = data;
stream.avail_in = left;
stream.next_out = buffer;
stream.avail_out = size;
inflateInit(&stream);
st = inflate(&stream, Z_FINISH);
inflateEnd(&stream);
if ((st != Z_STREAM_END) || stream.total_out != size) {
free(buffer);
return NULL;
}
return buffer;
}
static void *unpack_entry(struct pack_entry *entry,
char *type, unsigned long *sizep)
{
struct packed_git *p = entry->p;
void *retval;
if (use_packed_git(p))
die("cannot map packed file");
retval = unpack_entry_gently(entry, type, sizep);
unuse_packed_git(p);
if (!retval)
die("corrupted pack file %s", p->pack_name);
return retval;
}
/* The caller is responsible for use_packed_git()/unuse_packed_git() pair */
void *unpack_entry_gently(struct pack_entry *entry,
char *type, unsigned long *sizep)
{
struct packed_git *p = entry->p;
unsigned long offset, size, left;
unsigned char *pack;
enum object_type kind;
void *retval;
offset = unpack_object_header(p, entry->offset, &kind, &size);
pack = p->pack_base + offset;
left = p->pack_size - offset;
switch (kind) {
case OBJ_DELTA:
retval = unpack_delta_entry(pack, size, left, type, sizep, p);
return retval;
case OBJ_COMMIT:
strcpy(type, "commit");
break;
case OBJ_TREE:
strcpy(type, "tree");
break;
case OBJ_BLOB:
strcpy(type, "blob");
break;
case OBJ_TAG:
strcpy(type, "tag");
break;
default:
return NULL;
}
*sizep = size;
retval = unpack_non_delta_entry(pack, size, left);
return retval;
}
int num_packed_objects(const struct packed_git *p)
{
/* See check_packed_git_idx() */
return (p->index_size - 20 - 20 - 4*256) / 24;
}
int nth_packed_object_sha1(const struct packed_git *p, int n,
unsigned char* sha1)
{
void *index = p->index_base + 256;
if (n < 0 || num_packed_objects(p) <= n)
return -1;
memcpy(sha1, (index + 24 * n + 4), 20);
return 0;
}
int find_pack_entry_one(const unsigned char *sha1,
struct pack_entry *e, struct packed_git *p)
{
unsigned int *level1_ofs = p->index_base;
int hi = ntohl(level1_ofs[*sha1]);
int lo = ((*sha1 == 0x0) ? 0 : ntohl(level1_ofs[*sha1 - 1]));
void *index = p->index_base + 256;
do {
int mi = (lo + hi) / 2;
int cmp = memcmp(index + 24 * mi + 4, sha1, 20);
if (!cmp) {
e->offset = ntohl(*((int*)(index + 24 * mi)));
memcpy(e->sha1, sha1, 20);
e->p = p;
return 1;
}
if (cmp > 0)
hi = mi;
else
lo = mi+1;
} while (lo < hi);
return 0;
}
static int find_pack_entry(const unsigned char *sha1, struct pack_entry *e)
{
struct packed_git *p;
prepare_packed_git();
for (p = packed_git; p; p = p->next) {
if (find_pack_entry_one(sha1, e, p))
return 1;
}
return 0;
}
struct packed_git *find_sha1_pack(const unsigned char *sha1,
struct packed_git *packs)
{
struct packed_git *p;
struct pack_entry e;
for (p = packs; p; p = p->next) {
if (find_pack_entry_one(sha1, &e, p))
return p;
}
return NULL;
}
int sha1_object_info(const unsigned char *sha1, char *type, unsigned long *sizep)
{
int status;
unsigned long mapsize, size;
void *map;
z_stream stream;
char hdr[128];
map = map_sha1_file_internal(sha1, &mapsize);
if (!map) {
struct pack_entry e;
if (!find_pack_entry(sha1, &e))
return error("unable to find %s", sha1_to_hex(sha1));
return packed_object_info(&e, type, sizep);
}
if (unpack_sha1_header(&stream, map, mapsize, hdr, sizeof(hdr)) < 0)
status = error("unable to unpack %s header",
sha1_to_hex(sha1));
if (parse_sha1_header(hdr, type, &size) < 0)
status = error("unable to parse %s header", sha1_to_hex(sha1));
else {
status = 0;
if (sizep)
*sizep = size;
}
inflateEnd(&stream);
munmap(map, mapsize);
return status;
}
static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned long *size)
{
struct pack_entry e;
if (!find_pack_entry(sha1, &e)) {
error("cannot read sha1_file for %s", sha1_to_hex(sha1));
return NULL;
}
return unpack_entry(&e, type, size);
}
void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
{
unsigned long mapsize;
void *map, *buf;
struct pack_entry e;
if (find_pack_entry(sha1, &e))
return read_packed_sha1(sha1, type, size);
map = map_sha1_file_internal(sha1, &mapsize);
if (map) {
buf = unpack_sha1_file(map, mapsize, type, size);
munmap(map, mapsize);
return buf;
}
return NULL;
}
void *read_object_with_reference(const unsigned char *sha1,
const char *required_type,
unsigned long *size,
unsigned char *actual_sha1_return)
{
char type[20];
void *buffer;
unsigned long isize;
unsigned char actual_sha1[20];
memcpy(actual_sha1, sha1, 20);
while (1) {
int ref_length = -1;
const char *ref_type = NULL;
buffer = read_sha1_file(actual_sha1, type, &isize);
if (!buffer)
return NULL;
if (!strcmp(type, required_type)) {
*size = isize;
if (actual_sha1_return)
memcpy(actual_sha1_return, actual_sha1, 20);
return buffer;
}
/* Handle references */
else if (!strcmp(type, "commit"))
ref_type = "tree ";
else if (!strcmp(type, "tag"))
ref_type = "object ";
else {
free(buffer);
return NULL;
}
ref_length = strlen(ref_type);
if (memcmp(buffer, ref_type, ref_length) ||
get_sha1_hex(buffer + ref_length, actual_sha1)) {
free(buffer);
return NULL;
}
free(buffer);
/* Now we have the ID of the referred-to object in
* actual_sha1. Check again. */
}
}
char *write_sha1_file_prepare(void *buf,
unsigned long len,
const char *type,
unsigned char *sha1,
unsigned char *hdr,
int *hdrlen)
{
SHA_CTX c;
/* Generate the header */
*hdrlen = sprintf((char *)hdr, "%s %lu", type, len)+1;
/* Sha1.. */
SHA1_Init(&c);
SHA1_Update(&c, hdr, *hdrlen);
SHA1_Update(&c, buf, len);
SHA1_Final(sha1, &c);
return sha1_file_name(sha1);
}
/*
* Link the tempfile to the final place, possibly creating the
* last directory level as you do so.
*
* Returns the errno on failure, 0 on success.
*/
static int link_temp_to_file(const char *tmpfile, char *filename)
{
int ret;
if (!link(tmpfile, filename))
return 0;
/*
* Try to mkdir the last path component if that failed
* with an ENOENT.
*
* Re-try the "link()" regardless of whether the mkdir
* succeeds, since a race might mean that somebody
* else succeeded.
*/
ret = errno;
if (ret == ENOENT) {
char *dir = strrchr(filename, '/');
if (dir) {
*dir = 0;
mkdir(filename, 0777);
if (adjust_shared_perm(filename))
return -2;
*dir = '/';
if (!link(tmpfile, filename))
return 0;
ret = errno;
}
}
return ret;
}
/*
* Move the just written object into its final resting place
*/
int move_temp_to_file(const char *tmpfile, char *filename)
{
int ret = link_temp_to_file(tmpfile, filename);
/*
* Coda hack - coda doesn't like cross-directory links,
* so we fall back to a rename, which will mean that it
* won't be able to check collisions, but that's not a
* big deal.
*
* The same holds for FAT formatted media.
*
* When this succeeds, we just return 0. We have nothing
* left to unlink.
*/
if (ret && ret != EEXIST) {
if (!rename(tmpfile, filename))
return 0;
ret = errno;
}
unlink(tmpfile);
if (ret) {
if (ret != EEXIST) {
fprintf(stderr, "unable to write sha1 filename %s: %s\n", filename, strerror(ret));
return -1;
}
/* FIXME!!! Collision check here ? */
}
return 0;
}
int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *returnsha1)
{
int size;
unsigned char *compressed;
z_stream stream;
unsigned char sha1[20];
char *filename;
static char tmpfile[PATH_MAX];
unsigned char hdr[50];
int fd, hdrlen;
/* Normally if we have it in the pack then we do not bother writing
* it out into .git/objects/??/?{38} file.
*/
filename = write_sha1_file_prepare(buf, len, type, sha1, hdr, &hdrlen);
if (returnsha1)
memcpy(returnsha1, sha1, 20);
if (has_sha1_file(sha1))
return 0;
fd = open(filename, O_RDONLY);
if (fd >= 0) {
/*
* FIXME!!! We might do collision checking here, but we'd
* need to uncompress the old file and check it. Later.
*/
close(fd);
return 0;
}
if (errno != ENOENT) {
fprintf(stderr, "sha1 file %s: %s\n", filename, strerror(errno));
return -1;
}
snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
fd = mkstemp(tmpfile);
if (fd < 0) {
fprintf(stderr, "unable to create temporary sha1 filename %s: %s\n", tmpfile, strerror(errno));
return -1;
}
/* Set it up */
memset(&stream, 0, sizeof(stream));
deflateInit(&stream, Z_BEST_COMPRESSION);
size = deflateBound(&stream, len+hdrlen);
compressed = xmalloc(size);
/* Compress it */
stream.next_out = compressed;
stream.avail_out = size;
/* First header.. */
stream.next_in = hdr;
stream.avail_in = hdrlen;
while (deflate(&stream, 0) == Z_OK)
/* nothing */;
/* Then the data itself.. */
stream.next_in = buf;
stream.avail_in = len;
while (deflate(&stream, Z_FINISH) == Z_OK)
/* nothing */;
deflateEnd(&stream);
size = stream.total_out;
if (write(fd, compressed, size) != size)
die("unable to write file");
fchmod(fd, 0444);
close(fd);
free(compressed);
return move_temp_to_file(tmpfile, filename);
}
int write_sha1_to_fd(int fd, const unsigned char *sha1)
{
ssize_t size;
unsigned long objsize;
int posn = 0;
void *map = map_sha1_file_internal(sha1, &objsize);
void *buf = map;
void *temp_obj = NULL;
z_stream stream;
if (!buf) {
unsigned char *unpacked;
unsigned long len;
char type[20];
char hdr[50];
int hdrlen;
// need to unpack and recompress it by itself
unpacked = read_packed_sha1(sha1, type, &len);
hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;
/* Set it up */
memset(&stream, 0, sizeof(stream));
deflateInit(&stream, Z_BEST_COMPRESSION);
size = deflateBound(&stream, len + hdrlen);
temp_obj = buf = xmalloc(size);
/* Compress it */
stream.next_out = buf;
stream.avail_out = size;
/* First header.. */
stream.next_in = (void *)hdr;
stream.avail_in = hdrlen;
while (deflate(&stream, 0) == Z_OK)
/* nothing */;
/* Then the data itself.. */
stream.next_in = unpacked;
stream.avail_in = len;
while (deflate(&stream, Z_FINISH) == Z_OK)
/* nothing */;
deflateEnd(&stream);
free(unpacked);
objsize = stream.total_out;
}
do {
size = write(fd, buf + posn, objsize - posn);
if (size <= 0) {
if (!size) {
fprintf(stderr, "write closed\n");
} else {
perror("write ");
}
return -1;
}
posn += size;
} while (posn < objsize);
if (map)
munmap(map, objsize);
if (temp_obj)
free(temp_obj);
return 0;
}
int write_sha1_from_fd(const unsigned char *sha1, int fd, char *buffer,
size_t bufsize, size_t *bufposn)
{
char tmpfile[PATH_MAX];
int local;
z_stream stream;
unsigned char real_sha1[20];
unsigned char discard[4096];
int ret;
SHA_CTX c;
snprintf(tmpfile, sizeof(tmpfile), "%s/obj_XXXXXX", get_object_directory());
local = mkstemp(tmpfile);
if (local < 0)
return error("Couldn't open %s for %s\n", tmpfile, sha1_to_hex(sha1));
memset(&stream, 0, sizeof(stream));
inflateInit(&stream);
SHA1_Init(&c);
do {
ssize_t size;
if (*bufposn) {
stream.avail_in = *bufposn;
stream.next_in = (unsigned char *) buffer;
do {
stream.next_out = discard;
stream.avail_out = sizeof(discard);
ret = inflate(&stream, Z_SYNC_FLUSH);
SHA1_Update(&c, discard, sizeof(discard) -
stream.avail_out);
} while (stream.avail_in && ret == Z_OK);
write(local, buffer, *bufposn - stream.avail_in);
memmove(buffer, buffer + *bufposn - stream.avail_in,
stream.avail_in);
*bufposn = stream.avail_in;
if (ret != Z_OK)
break;
}
size = read(fd, buffer + *bufposn, bufsize - *bufposn);
if (size <= 0) {
close(local);
unlink(tmpfile);
if (!size)
return error("Connection closed?");
perror("Reading from connection");
return -1;
}
*bufposn += size;
} while (1);
inflateEnd(&stream);
close(local);
SHA1_Final(real_sha1, &c);
if (ret != Z_STREAM_END) {
unlink(tmpfile);
return error("File %s corrupted", sha1_to_hex(sha1));
}
if (memcmp(sha1, real_sha1, 20)) {
unlink(tmpfile);
return error("File %s has bad hash\n", sha1_to_hex(sha1));
}
return move_temp_to_file(tmpfile, sha1_file_name(sha1));
}
int has_pack_index(const unsigned char *sha1)
{
struct stat st;
if (stat(sha1_pack_index_name(sha1), &st))
return 0;
return 1;
}
int has_pack_file(const unsigned char *sha1)
{
struct stat st;
if (stat(sha1_pack_name(sha1), &st))
return 0;
return 1;
}
int has_sha1_pack(const unsigned char *sha1)
{
struct pack_entry e;
return find_pack_entry(sha1, &e);
}
int has_sha1_file(const unsigned char *sha1)
{
struct stat st;
struct pack_entry e;
if (find_pack_entry(sha1, &e))
return 1;
return find_sha1_file(sha1, &st) ? 1 : 0;
}
int index_pipe(unsigned char *sha1, int fd, const char *type, int write_object)
{
unsigned long size = 4096;
char *buf = malloc(size);
int iret, ret;
unsigned long off = 0;
unsigned char hdr[50];
int hdrlen;
do {
iret = read(fd, buf + off, size - off);
if (iret > 0) {
off += iret;
if (off == size) {
size *= 2;
buf = realloc(buf, size);
}
}
} while (iret > 0);
if (iret < 0) {
free(buf);
return -1;
}
if (!type)
type = "blob";
if (write_object)
ret = write_sha1_file(buf, off, type, sha1);
else {
write_sha1_file_prepare(buf, off, type, sha1, hdr, &hdrlen);
ret = 0;
}
free(buf);
return ret;
}
int index_fd(unsigned char *sha1, int fd, struct stat *st, int write_object, const char *type)
{
unsigned long size = st->st_size;
void *buf;
int ret;
unsigned char hdr[50];
int hdrlen;
buf = "";
if (size)
buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
close(fd);
if (buf == MAP_FAILED)
return -1;
if (!type)
type = "blob";
if (write_object)
ret = write_sha1_file(buf, size, type, sha1);
else {
write_sha1_file_prepare(buf, size, type, sha1, hdr, &hdrlen);
ret = 0;
}
if (size)
munmap(buf, size);
return ret;
}
int index_path(unsigned char *sha1, const char *path, struct stat *st, int write_object)
{
int fd;
char *target;
switch (st->st_mode & S_IFMT) {
case S_IFREG:
fd = open(path, O_RDONLY);
if (fd < 0)
return error("open(\"%s\"): %s", path,
strerror(errno));
if (index_fd(sha1, fd, st, write_object, NULL) < 0)
return error("%s: failed to insert into database",
path);
break;
case S_IFLNK:
target = xmalloc(st->st_size+1);
if (readlink(path, target, st->st_size+1) != st->st_size) {
char *errstr = strerror(errno);
free(target);
return error("readlink(\"%s\"): %s", path,
errstr);
}
if (!write_object) {
unsigned char hdr[50];
int hdrlen;
write_sha1_file_prepare(target, st->st_size, "blob",
sha1, hdr, &hdrlen);
} else if (write_sha1_file(target, st->st_size, "blob", sha1))
return error("%s: failed to insert into database",
path);
free(target);
break;
default:
return error("%s: unsupported file type", path);
}
return 0;
}
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