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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 <sys/types.h>
#include <dirent.h>
#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

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;
}

static int get_sha1_file(const char *path, unsigned char *result)
{
char buffer[60];
int fd = open(path, O_RDONLY);
int len;

if (fd < 0)
return -1;
len = read(fd, buffer, sizeof(buffer));
close(fd);
if (len < 40)
return -1;
return get_sha1_hex(buffer, result);
}

static char *git_dir, *git_object_dir, *git_index_file, *git_refs_dir;
static void setup_git_env(void)
{
git_dir = gitenv(GIT_DIR_ENVIRONMENT);
if (!git_dir)
git_dir = DEFAULT_GIT_DIR_ENVIRONMENT;
git_object_dir = gitenv(DB_ENVIRONMENT);
if (!git_object_dir) {
git_object_dir = xmalloc(strlen(git_dir) + 9);
sprintf(git_object_dir, "%s/objects", git_dir);
}
git_refs_dir = xmalloc(strlen(git_dir) + 6);
sprintf(git_refs_dir, "%s/refs", git_dir);
git_index_file = gitenv(INDEX_ENVIRONMENT);
if (!git_index_file) {
git_index_file = xmalloc(strlen(git_dir) + 7);
sprintf(git_index_file, "%s/index", git_dir);
}
}

char *get_object_directory(void)
{
if (!git_object_dir)
setup_git_env();
return git_object_dir;
}

char *get_refs_directory(void)
{
if (!git_refs_dir)
setup_git_env();
return git_refs_dir;
}

char *get_index_file(void)
{
if (!git_index_file)
setup_git_env();
return git_index_file;
}

int safe_create_leading_directories(char *path)
{
char *pos = path;

while (pos) {
pos = strchr(pos, '/');
if (!pos)
break;
*pos = 0;
if (mkdir(path, 0777) < 0)
if (errno != EEXIST) {
*pos = '/';
return -1;
}
*pos++ = '/';
}
return 0;
}

int get_sha1(const char *str, unsigned char *sha1)
{
static const char *prefix[] = {
"",
"refs",
"refs/tags",
"refs/heads",
"refs/snap",
NULL
};
const char **p;

if (!get_sha1_hex(str, sha1))
return 0;

for (p = prefix; *p; p++) {
char * pathname = git_path("%s/%s", *p, str);
if (!get_sha1_file(pathname, sha1))
return 0;
}

return -1;
}

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];
}
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;
}

struct alternate_object_database *alt_odb;

/*
* Prepare alternate object database registry.
* alt_odb points at an array of struct alternate_object_database.
* This array is terminated with an element that has both its base
* and name set to NULL. alt_odb[n] comes from n'th non-empty
* element from colon separated ALTERNATE_DB_ENVIRONMENT environment
* variable, and 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.
* This function allocates the alt_odb array and all the strings
* pointed by base fields of the array elements with one xmalloc();
* the string pool immediately follows the array.
*/
void prepare_alt_odb(void)
{
int pass, totlen, i;
const char *cp, *last;
char *op = NULL;
const char *alt = gitenv(ALTERNATE_DB_ENVIRONMENT) ? : "";

if (alt_odb)
return;
/* The first pass counts how large an area to allocate to
* hold the entire alt_odb structure, including array of
* structs and path buffers for them. The second pass fills
* the structure and prepares the path buffers for use by
* fill_sha1_path().
*/
for (totlen = pass = 0; pass < 2; pass++) {
last = alt;
i = 0;
do {
cp = strchr(last, ':') ? : last + strlen(last);
if (last != cp) {
/* 43 = 40-byte + 2 '/' + terminating NUL */
int pfxlen = cp - last;
int entlen = pfxlen + 43;
if (pass == 0)
totlen += entlen;
else {
alt_odb[i].base = op;
alt_odb[i].name = op + pfxlen + 1;
memcpy(op, last, pfxlen);
op[pfxlen] = op[pfxlen + 3] = '/';
op[entlen-1] = 0;
op += entlen;
}
i++;
}
while (*cp && *cp == ':')
cp++;
last = cp;
} while (*cp);
if (pass)
break;
alt_odb = xmalloc(sizeof(*alt_odb) * (i + 1) + totlen);
alt_odb[i].base = alt_odb[i].name = NULL;
op = (char*)(&alt_odb[i+1]);
}
}

static char *find_sha1_file(const unsigned char *sha1, struct stat *st)
{
int i;
char *name = sha1_file_name(sha1);

if (!stat(name, st))
return name;
prepare_alt_odb();
for (i = 0; (name = alt_odb[i].name) != NULL; i++) {
fill_sha1_path(name, sha1);
if (!stat(alt_odb[i].base, st))
return alt_odb[i].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_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)
{
struct stat st;
struct packed_git *p;
unsigned long idx_size;
void *idx_map;

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;
return p;
}

static void prepare_packed_git_one(char *objdir)
{
char path[PATH_MAX];
int len;
DIR *dir;
struct dirent *de;

sprintf(path, "%s/pack", objdir);
len = strlen(path);
dir = opendir(path);
if (!dir)
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);
if (!p)
continue;
p->next = packed_git;
packed_git = p;
}
closedir(dir);
}

void prepare_packed_git(void)
{
int i;
static int run_once = 0;

if (run_once++)
return;

prepare_packed_git_one(get_object_directory());
prepare_alt_odb();
for (i = 0; alt_odb[i].base != NULL; i++) {
alt_odb[i].name[0] = 0;
prepare_packed_git_one(alt_odb[i].base);
}
}

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 (-1 == (int)(long)map)
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;
}

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");
}
*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");
}
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");
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;
}

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;

map = map_sha1_file_internal(sha1, &mapsize);
if (map) {
buf = unpack_sha1_file(map, mapsize, type, size);
munmap(map, mapsize);
return buf;
}
return read_packed_sha1(sha1, type, size);
}

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;
}
/* 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);
}

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, ret;

/* 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", 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", 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);

ret = link(tmpfile, filename);
if (ret < 0) {
ret = errno;

/*
* 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.
*
* When this succeeds, we just return 0. We have nothing
* left to unlink.
*/
if (ret == EXDEV && !rename(tmpfile, filename))
return 0;
}
unlink(tmpfile);
if (ret) {
if (ret != EEXIST) {
fprintf(stderr, "unable to write sha1 filename %s: %s", filename, strerror(ret));
return -1;
}
/* FIXME!!! Collision check here ? */
}

return 0;
}

int write_sha1_to_fd(int fd, const unsigned char *sha1)
{
ssize_t size;
unsigned long objsize;
int posn = 0;
void *buf = map_sha1_file_internal(sha1, &objsize);
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);
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);

objsize = stream.total_out;
}

do {
size = write(fd, buf + posn, objsize - posn);
if (size <= 0) {
if (!size) {
fprintf(stderr, "write closed");
} else {
perror("write ");
}
return -1;
}
posn += size;
} while (posn < objsize);
return 0;
}

int write_sha1_from_fd(const unsigned char *sha1, int fd)
{
char *filename = sha1_file_name(sha1);

int local;
z_stream stream;
unsigned char real_sha1[20];
unsigned char buf[4096];
unsigned char discard[4096];
int ret;
SHA_CTX c;

local = open(filename, O_WRONLY | O_CREAT | O_EXCL, 0666);

if (local < 0)
return error("Couldn't open %s\n", filename);

memset(&stream, 0, sizeof(stream));

inflateInit(&stream);

SHA1_Init(&c);

do {
ssize_t size;
size = read(fd, buf, 4096);
if (size <= 0) {
close(local);
unlink(filename);
if (!size)
return error("Connection closed?");
perror("Reading from connection");
return -1;
}
write(local, buf, size);
stream.avail_in = size;
stream.next_in = buf;
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);

} while (ret == Z_OK);
inflateEnd(&stream);

close(local);
SHA1_Final(real_sha1, &c);
if (ret != Z_STREAM_END) {
unlink(filename);
return error("File %s corrupted", sha1_to_hex(sha1));
}
if (memcmp(sha1, real_sha1, 20)) {
unlink(filename);
return error("File %s has bad hash\n", sha1_to_hex(sha1));
}

return 0;
}

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_sha1_file(sha1, &st))
return 1;
return find_pack_entry(sha1, &e);
}

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 ((int)(long)buf == -1)
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;
}
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