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Copy pathunpack-objects.c
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597 lines (533 loc) · 13.9 KB
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#include "builtin.h"
#include "cache.h"
#include "config.h"
#include "object-store.h"
#include "object.h"
#include "delta.h"
#include "pack.h"
#include "blob.h"
#include "commit.h"
#include "tag.h"
#include "tree.h"
#include "tree-walk.h"
#include "progress.h"
#include "decorate.h"
#include "fsck.h"
static int dry_run, quiet, recover, has_errors, strict;
static const char unpack_usage[] = "git unpack-objects [-n] [-q] [-r] [--strict]";
/* We always read in 4kB chunks. */
static unsigned char buffer[4096];
static unsigned int offset, len;
static off_t consumed_bytes;
static off_t max_input_size;
static git_hash_ctx ctx;
static struct fsck_options fsck_options = FSCK_OPTIONS_STRICT;
/*
* When running under --strict mode, objects whose reachability are
* suspect are kept in core without getting written in the object
* store.
*/
struct obj_buffer {
char *buffer;
unsigned long size;
};
static struct decoration obj_decorate;
static struct obj_buffer *lookup_object_buffer(struct object *base)
{
return lookup_decoration(&obj_decorate, base);
}
static void add_object_buffer(struct object *object, char *buffer, unsigned long size)
{
struct obj_buffer *obj;
obj = xcalloc(1, sizeof(struct obj_buffer));
obj->buffer = buffer;
obj->size = size;
if (add_decoration(&obj_decorate, object, obj))
die("object %s tried to add buffer twice!", oid_to_hex(&object->oid));
}
/*
* Make sure at least "min" bytes are available in the buffer, and
* return the pointer to the buffer.
*/
static void *fill(int min)
{
if (min <= len)
return buffer + offset;
if (min > sizeof(buffer))
die("cannot fill %d bytes", min);
if (offset) {
the_hash_algo->update_fn(&ctx, buffer, offset);
memmove(buffer, buffer + offset, len);
offset = 0;
}
do {
ssize_t ret = xread(0, buffer + len, sizeof(buffer) - len);
if (ret <= 0) {
if (!ret)
die("early EOF");
die_errno("read error on input");
}
len += ret;
} while (len < min);
return buffer;
}
static void use(int bytes)
{
if (bytes > len)
die("used more bytes than were available");
len -= bytes;
offset += bytes;
/* make sure off_t is sufficiently large not to wrap */
if (signed_add_overflows(consumed_bytes, bytes))
die("pack too large for current definition of off_t");
consumed_bytes += bytes;
if (max_input_size && consumed_bytes > max_input_size)
die(_("pack exceeds maximum allowed size"));
}
static void *get_data(unsigned long size)
{
git_zstream stream;
void *buf = xmallocz(size);
memset(&stream, 0, sizeof(stream));
stream.next_out = buf;
stream.avail_out = size;
stream.next_in = fill(1);
stream.avail_in = len;
git_inflate_init(&stream);
for (;;) {
int ret = git_inflate(&stream, 0);
use(len - stream.avail_in);
if (stream.total_out == size && ret == Z_STREAM_END)
break;
if (ret != Z_OK) {
error("inflate returned %d", ret);
FREE_AND_NULL(buf);
if (!recover)
exit(1);
has_errors = 1;
break;
}
stream.next_in = fill(1);
stream.avail_in = len;
}
git_inflate_end(&stream);
return buf;
}
struct delta_info {
struct object_id base_oid;
unsigned nr;
off_t base_offset;
unsigned long size;
void *delta;
struct delta_info *next;
};
static struct delta_info *delta_list;
static void add_delta_to_list(unsigned nr, const struct object_id *base_oid,
off_t base_offset,
void *delta, unsigned long size)
{
struct delta_info *info = xmalloc(sizeof(*info));
oidcpy(&info->base_oid, base_oid);
info->base_offset = base_offset;
info->size = size;
info->delta = delta;
info->nr = nr;
info->next = delta_list;
delta_list = info;
}
struct obj_info {
off_t offset;
struct object_id oid;
struct object *obj;
};
/* Remember to update object flag allocation in object.h */
#define FLAG_OPEN (1u<<20)
#define FLAG_WRITTEN (1u<<21)
static struct obj_info *obj_list;
static unsigned nr_objects;
/*
* Called only from check_object() after it verified this object
* is Ok.
*/
static void write_cached_object(struct object *obj, struct obj_buffer *obj_buf)
{
struct object_id oid;
if (write_object_file(obj_buf->buffer, obj_buf->size,
type_name(obj->type), &oid) < 0)
die("failed to write object %s", oid_to_hex(&obj->oid));
obj->flags |= FLAG_WRITTEN;
}
/*
* At the very end of the processing, write_rest() scans the objects
* that have reachability requirements and calls this function.
* Verify its reachability and validity recursively and write it out.
*/
static int check_object(struct object *obj, int type, void *data, struct fsck_options *options)
{
struct obj_buffer *obj_buf;
if (!obj)
return 1;
if (obj->flags & FLAG_WRITTEN)
return 0;
if (type != OBJ_ANY && obj->type != type)
die("object type mismatch");
if (!(obj->flags & FLAG_OPEN)) {
unsigned long size;
int type = oid_object_info(the_repository, &obj->oid, &size);
if (type != obj->type || type <= 0)
die("object of unexpected type");
obj->flags |= FLAG_WRITTEN;
return 0;
}
obj_buf = lookup_object_buffer(obj);
if (!obj_buf)
die("Whoops! Cannot find object '%s'", oid_to_hex(&obj->oid));
if (fsck_object(obj, obj_buf->buffer, obj_buf->size, &fsck_options))
die("fsck error in packed object");
fsck_options.walk = check_object;
if (fsck_walk(obj, NULL, &fsck_options))
die("Error on reachable objects of %s", oid_to_hex(&obj->oid));
write_cached_object(obj, obj_buf);
return 0;
}
static void write_rest(void)
{
unsigned i;
for (i = 0; i < nr_objects; i++) {
if (obj_list[i].obj)
check_object(obj_list[i].obj, OBJ_ANY, NULL, NULL);
}
}
static void added_object(unsigned nr, enum object_type type,
void *data, unsigned long size);
/*
* Write out nr-th object from the list, now we know the contents
* of it. Under --strict, this buffers structured objects in-core,
* to be checked at the end.
*/
static void write_object(unsigned nr, enum object_type type,
void *buf, unsigned long size)
{
if (!strict) {
if (write_object_file(buf, size, type_name(type),
&obj_list[nr].oid) < 0)
die("failed to write object");
added_object(nr, type, buf, size);
free(buf);
obj_list[nr].obj = NULL;
} else if (type == OBJ_BLOB) {
struct blob *blob;
if (write_object_file(buf, size, type_name(type),
&obj_list[nr].oid) < 0)
die("failed to write object");
added_object(nr, type, buf, size);
free(buf);
blob = lookup_blob(the_repository, &obj_list[nr].oid);
if (blob)
blob->object.flags |= FLAG_WRITTEN;
else
die("invalid blob object");
obj_list[nr].obj = NULL;
} else {
struct object *obj;
int eaten;
hash_object_file(buf, size, type_name(type), &obj_list[nr].oid);
added_object(nr, type, buf, size);
obj = parse_object_buffer(the_repository, &obj_list[nr].oid,
type, size, buf,
&eaten);
if (!obj)
die("invalid %s", type_name(type));
add_object_buffer(obj, buf, size);
obj->flags |= FLAG_OPEN;
obj_list[nr].obj = obj;
}
}
static void resolve_delta(unsigned nr, enum object_type type,
void *base, unsigned long base_size,
void *delta, unsigned long delta_size)
{
void *result;
unsigned long result_size;
result = patch_delta(base, base_size,
delta, delta_size,
&result_size);
if (!result)
die("failed to apply delta");
free(delta);
write_object(nr, type, result, result_size);
}
/*
* We now know the contents of an object (which is nr-th in the pack);
* resolve all the deltified objects that are based on it.
*/
static void added_object(unsigned nr, enum object_type type,
void *data, unsigned long size)
{
struct delta_info **p = &delta_list;
struct delta_info *info;
while ((info = *p) != NULL) {
if (oideq(&info->base_oid, &obj_list[nr].oid) ||
info->base_offset == obj_list[nr].offset) {
*p = info->next;
p = &delta_list;
resolve_delta(info->nr, type, data, size,
info->delta, info->size);
free(info);
continue;
}
p = &info->next;
}
}
static void unpack_non_delta_entry(enum object_type type, unsigned long size,
unsigned nr)
{
void *buf = get_data(size);
if (!dry_run && buf)
write_object(nr, type, buf, size);
else
free(buf);
}
static int resolve_against_held(unsigned nr, const struct object_id *base,
void *delta_data, unsigned long delta_size)
{
struct object *obj;
struct obj_buffer *obj_buffer;
obj = lookup_object(the_repository, base->hash);
if (!obj)
return 0;
obj_buffer = lookup_object_buffer(obj);
if (!obj_buffer)
return 0;
resolve_delta(nr, obj->type, obj_buffer->buffer,
obj_buffer->size, delta_data, delta_size);
return 1;
}
static void unpack_delta_entry(enum object_type type, unsigned long delta_size,
unsigned nr)
{
void *delta_data, *base;
unsigned long base_size;
struct object_id base_oid;
if (type == OBJ_REF_DELTA) {
hashcpy(base_oid.hash, fill(the_hash_algo->rawsz));
use(the_hash_algo->rawsz);
delta_data = get_data(delta_size);
if (dry_run || !delta_data) {
free(delta_data);
return;
}
if (has_object_file(&base_oid))
; /* Ok we have this one */
else if (resolve_against_held(nr, &base_oid,
delta_data, delta_size))
return; /* we are done */
else {
/* cannot resolve yet --- queue it */
oidclr(&obj_list[nr].oid);
add_delta_to_list(nr, &base_oid, 0, delta_data, delta_size);
return;
}
} else {
unsigned base_found = 0;
unsigned char *pack, c;
off_t base_offset;
unsigned lo, mid, hi;
pack = fill(1);
c = *pack;
use(1);
base_offset = c & 127;
while (c & 128) {
base_offset += 1;
if (!base_offset || MSB(base_offset, 7))
die("offset value overflow for delta base object");
pack = fill(1);
c = *pack;
use(1);
base_offset = (base_offset << 7) + (c & 127);
}
base_offset = obj_list[nr].offset - base_offset;
if (base_offset <= 0 || base_offset >= obj_list[nr].offset)
die("offset value out of bound for delta base object");
delta_data = get_data(delta_size);
if (dry_run || !delta_data) {
free(delta_data);
return;
}
lo = 0;
hi = nr;
while (lo < hi) {
mid = lo + (hi - lo) / 2;
if (base_offset < obj_list[mid].offset) {
hi = mid;
} else if (base_offset > obj_list[mid].offset) {
lo = mid + 1;
} else {
oidcpy(&base_oid, &obj_list[mid].oid);
base_found = !is_null_oid(&base_oid);
break;
}
}
if (!base_found) {
/*
* The delta base object is itself a delta that
* has not been resolved yet.
*/
oidclr(&obj_list[nr].oid);
add_delta_to_list(nr, &null_oid, base_offset, delta_data, delta_size);
return;
}
}
if (resolve_against_held(nr, &base_oid, delta_data, delta_size))
return;
base = read_object_file(&base_oid, &type, &base_size);
if (!base) {
error("failed to read delta-pack base object %s",
oid_to_hex(&base_oid));
if (!recover)
exit(1);
has_errors = 1;
return;
}
resolve_delta(nr, type, base, base_size, delta_data, delta_size);
free(base);
}
static void unpack_one(unsigned nr)
{
unsigned shift;
unsigned char *pack;
unsigned long size, c;
enum object_type type;
obj_list[nr].offset = consumed_bytes;
pack = fill(1);
c = *pack;
use(1);
type = (c >> 4) & 7;
size = (c & 15);
shift = 4;
while (c & 0x80) {
pack = fill(1);
c = *pack;
use(1);
size += (c & 0x7f) << shift;
shift += 7;
}
switch (type) {
case OBJ_COMMIT:
case OBJ_TREE:
case OBJ_BLOB:
case OBJ_TAG:
unpack_non_delta_entry(type, size, nr);
return;
case OBJ_REF_DELTA:
case OBJ_OFS_DELTA:
unpack_delta_entry(type, size, nr);
return;
default:
error("bad object type %d", type);
has_errors = 1;
if (recover)
return;
exit(1);
}
}
static void unpack_all(void)
{
int i;
struct progress *progress = NULL;
struct pack_header *hdr = fill(sizeof(struct pack_header));
nr_objects = ntohl(hdr->hdr_entries);
if (ntohl(hdr->hdr_signature) != PACK_SIGNATURE)
die("bad pack file");
if (!pack_version_ok(hdr->hdr_version))
die("unknown pack file version %"PRIu32,
ntohl(hdr->hdr_version));
use(sizeof(struct pack_header));
if (!quiet)
progress = start_progress(_("Unpacking objects"), nr_objects);
obj_list = xcalloc(nr_objects, sizeof(*obj_list));
for (i = 0; i < nr_objects; i++) {
unpack_one(i);
display_progress(progress, i + 1);
}
stop_progress(&progress);
if (delta_list)
die("unresolved deltas left after unpacking");
}
int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
{
int i;
struct object_id oid;
read_replace_refs = 0;
git_config(git_default_config, NULL);
quiet = !isatty(2);
for (i = 1 ; i < argc; i++) {
const char *arg = argv[i];
if (*arg == '-') {
if (!strcmp(arg, "-n")) {
dry_run = 1;
continue;
}
if (!strcmp(arg, "-q")) {
quiet = 1;
continue;
}
if (!strcmp(arg, "-r")) {
recover = 1;
continue;
}
if (!strcmp(arg, "--strict")) {
strict = 1;
continue;
}
if (skip_prefix(arg, "--strict=", &arg)) {
strict = 1;
fsck_set_msg_types(&fsck_options, arg);
continue;
}
if (starts_with(arg, "--pack_header=")) {
struct pack_header *hdr;
char *c;
hdr = (struct pack_header *)buffer;
hdr->hdr_signature = htonl(PACK_SIGNATURE);
hdr->hdr_version = htonl(strtoul(arg + 14, &c, 10));
if (*c != ',')
die("bad %s", arg);
hdr->hdr_entries = htonl(strtoul(c + 1, &c, 10));
if (*c)
die("bad %s", arg);
len = sizeof(*hdr);
continue;
}
if (skip_prefix(arg, "--max-input-size=", &arg)) {
max_input_size = strtoumax(arg, NULL, 10);
continue;
}
usage(unpack_usage);
}
/* We don't take any non-flag arguments now.. Maybe some day */
usage(unpack_usage);
}
the_hash_algo->init_fn(&ctx);
unpack_all();
the_hash_algo->update_fn(&ctx, buffer, offset);
the_hash_algo->final_fn(oid.hash, &ctx);
if (strict) {
write_rest();
if (fsck_finish(&fsck_options))
die(_("fsck error in pack objects"));
}
if (!hasheq(fill(the_hash_algo->rawsz), oid.hash))
die("final sha1 did not match");
use(the_hash_algo->rawsz);
/* Write the last part of the buffer to stdout */
while (len) {
int ret = xwrite(1, buffer + offset, len);
if (ret <= 0)
break;
len -= ret;
offset += ret;
}
/* All done */
return has_errors;
}
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