git/bundle.c
Jiang Xin 5bb0fd2cab bundle: arguments can be read from stdin
In order to create an incremental bundle, we need to pass many arguments
to let git-bundle ignore some already packed commits.  It will be more
convenient to pass args via stdin.  But the current implementation does
not allow us to do this.

This is because args are parsed twice when creating bundle.  The first
time for parsing args is in `compute_and_write_prerequisites()` by
running `git-rev-list` command to write prerequisites in bundle file,
and stdin is consumed in this step if "--stdin" option is provided for
`git-bundle`.  Later nothing can be read from stdin when running
`setup_revisions()` in `create_bundle()`.

The solution is to parse args once by removing the entire function
`compute_and_write_prerequisites()` and then calling function
`setup_revisions()`.  In order to write prerequisites for bundle, will
call `prepare_revision_walk()` and `traverse_commit_list()`.  But after
calling `prepare_revision_walk()`, the object array `revs.pending` is
left empty, and the following steps could not work properly with the
empty object array (`revs.pending`).  Therefore, make a copy of `revs`
to `revs_copy` for later use right after calling `setup_revisions()`.

The copy of `revs_copy` is not a deep copy, it shares the same objects
with `revs`. The object array of `revs` has been cleared, but objects
themselves are still kept.  Flags of objects may change after calling
`prepare_revision_walk()`, we can use these changed flags without
calling the `git rev-list` command and parsing its output like the
former implementation.

Also add testcases for git bundle in t6020, which read args from stdin.

Signed-off-by: Jiang Xin <zhiyou.jx@alibaba-inc.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-11 21:50:41 -08:00

577 lines
15 KiB
C

#include "cache.h"
#include "lockfile.h"
#include "bundle.h"
#include "object-store.h"
#include "repository.h"
#include "object.h"
#include "commit.h"
#include "diff.h"
#include "revision.h"
#include "list-objects.h"
#include "run-command.h"
#include "refs.h"
#include "strvec.h"
static const char v2_bundle_signature[] = "# v2 git bundle\n";
static const char v3_bundle_signature[] = "# v3 git bundle\n";
static struct {
int version;
const char *signature;
} bundle_sigs[] = {
{ 2, v2_bundle_signature },
{ 3, v3_bundle_signature },
};
static void add_to_ref_list(const struct object_id *oid, const char *name,
struct ref_list *list)
{
ALLOC_GROW(list->list, list->nr + 1, list->alloc);
oidcpy(&list->list[list->nr].oid, oid);
list->list[list->nr].name = xstrdup(name);
list->nr++;
}
static int parse_capability(struct bundle_header *header, const char *capability)
{
const char *arg;
if (skip_prefix(capability, "object-format=", &arg)) {
int algo = hash_algo_by_name(arg);
if (algo == GIT_HASH_UNKNOWN)
return error(_("unrecognized bundle hash algorithm: %s"), arg);
header->hash_algo = &hash_algos[algo];
return 0;
}
return error(_("unknown capability '%s'"), capability);
}
static int parse_bundle_signature(struct bundle_header *header, const char *line)
{
int i;
for (i = 0; i < ARRAY_SIZE(bundle_sigs); i++) {
if (!strcmp(line, bundle_sigs[i].signature)) {
header->version = bundle_sigs[i].version;
return 0;
}
}
return -1;
}
static int parse_bundle_header(int fd, struct bundle_header *header,
const char *report_path)
{
struct strbuf buf = STRBUF_INIT;
int status = 0;
/* The bundle header begins with the signature */
if (strbuf_getwholeline_fd(&buf, fd, '\n') ||
parse_bundle_signature(header, buf.buf)) {
if (report_path)
error(_("'%s' does not look like a v2 or v3 bundle file"),
report_path);
status = -1;
goto abort;
}
header->hash_algo = the_hash_algo;
/* The bundle header ends with an empty line */
while (!strbuf_getwholeline_fd(&buf, fd, '\n') &&
buf.len && buf.buf[0] != '\n') {
struct object_id oid;
int is_prereq = 0;
const char *p;
strbuf_rtrim(&buf);
if (header->version == 3 && *buf.buf == '@') {
if (parse_capability(header, buf.buf + 1)) {
status = -1;
break;
}
continue;
}
if (*buf.buf == '-') {
is_prereq = 1;
strbuf_remove(&buf, 0, 1);
}
/*
* Tip lines have object name, SP, and refname.
* Prerequisites have object name that is optionally
* followed by SP and subject line.
*/
if (parse_oid_hex_algop(buf.buf, &oid, &p, header->hash_algo) ||
(*p && !isspace(*p)) ||
(!is_prereq && !*p)) {
if (report_path)
error(_("unrecognized header: %s%s (%d)"),
(is_prereq ? "-" : ""), buf.buf, (int)buf.len);
status = -1;
break;
} else {
if (is_prereq)
add_to_ref_list(&oid, "", &header->prerequisites);
else
add_to_ref_list(&oid, p + 1, &header->references);
}
}
abort:
if (status) {
close(fd);
fd = -1;
}
strbuf_release(&buf);
return fd;
}
int read_bundle_header(const char *path, struct bundle_header *header)
{
int fd = open(path, O_RDONLY);
if (fd < 0)
return error(_("could not open '%s'"), path);
return parse_bundle_header(fd, header, path);
}
int is_bundle(const char *path, int quiet)
{
struct bundle_header header;
int fd = open(path, O_RDONLY);
if (fd < 0)
return 0;
memset(&header, 0, sizeof(header));
fd = parse_bundle_header(fd, &header, quiet ? NULL : path);
if (fd >= 0)
close(fd);
return (fd >= 0);
}
static int list_refs(struct ref_list *r, int argc, const char **argv)
{
int i;
for (i = 0; i < r->nr; i++) {
if (argc > 1) {
int j;
for (j = 1; j < argc; j++)
if (!strcmp(r->list[i].name, argv[j]))
break;
if (j == argc)
continue;
}
printf("%s %s\n", oid_to_hex(&r->list[i].oid),
r->list[i].name);
}
return 0;
}
/* Remember to update object flag allocation in object.h */
#define PREREQ_MARK (1u<<16)
int verify_bundle(struct repository *r,
struct bundle_header *header,
int verbose)
{
/*
* Do fast check, then if any prereqs are missing then go line by line
* to be verbose about the errors
*/
struct ref_list *p = &header->prerequisites;
struct rev_info revs;
const char *argv[] = {NULL, "--all", NULL};
struct commit *commit;
int i, ret = 0, req_nr;
const char *message = _("Repository lacks these prerequisite commits:");
if (!r || !r->objects || !r->objects->odb)
return error(_("need a repository to verify a bundle"));
repo_init_revisions(r, &revs, NULL);
for (i = 0; i < p->nr; i++) {
struct ref_list_entry *e = p->list + i;
struct object *o = parse_object(r, &e->oid);
if (o) {
o->flags |= PREREQ_MARK;
add_pending_object(&revs, o, e->name);
continue;
}
if (++ret == 1)
error("%s", message);
error("%s %s", oid_to_hex(&e->oid), e->name);
}
if (revs.pending.nr != p->nr)
return ret;
req_nr = revs.pending.nr;
setup_revisions(2, argv, &revs, NULL);
if (prepare_revision_walk(&revs))
die(_("revision walk setup failed"));
i = req_nr;
while (i && (commit = get_revision(&revs)))
if (commit->object.flags & PREREQ_MARK)
i--;
for (i = 0; i < p->nr; i++) {
struct ref_list_entry *e = p->list + i;
struct object *o = parse_object(r, &e->oid);
assert(o); /* otherwise we'd have returned early */
if (o->flags & SHOWN)
continue;
if (++ret == 1)
error("%s", message);
error("%s %s", oid_to_hex(&e->oid), e->name);
}
/* Clean up objects used, as they will be reused. */
for (i = 0; i < p->nr; i++) {
struct ref_list_entry *e = p->list + i;
commit = lookup_commit_reference_gently(r, &e->oid, 1);
if (commit)
clear_commit_marks(commit, ALL_REV_FLAGS);
}
if (verbose) {
struct ref_list *r;
r = &header->references;
printf_ln(Q_("The bundle contains this ref:",
"The bundle contains these %d refs:",
r->nr),
r->nr);
list_refs(r, 0, NULL);
r = &header->prerequisites;
if (!r->nr) {
printf_ln(_("The bundle records a complete history."));
} else {
printf_ln(Q_("The bundle requires this ref:",
"The bundle requires these %d refs:",
r->nr),
r->nr);
list_refs(r, 0, NULL);
}
}
return ret;
}
int list_bundle_refs(struct bundle_header *header, int argc, const char **argv)
{
return list_refs(&header->references, argc, argv);
}
static int is_tag_in_date_range(struct object *tag, struct rev_info *revs)
{
unsigned long size;
enum object_type type;
char *buf = NULL, *line, *lineend;
timestamp_t date;
int result = 1;
if (revs->max_age == -1 && revs->min_age == -1)
goto out;
buf = read_object_file(&tag->oid, &type, &size);
if (!buf)
goto out;
line = memmem(buf, size, "\ntagger ", 8);
if (!line++)
goto out;
lineend = memchr(line, '\n', buf + size - line);
line = memchr(line, '>', lineend ? lineend - line : buf + size - line);
if (!line++)
goto out;
date = parse_timestamp(line, NULL, 10);
result = (revs->max_age == -1 || revs->max_age < date) &&
(revs->min_age == -1 || revs->min_age > date);
out:
free(buf);
return result;
}
/* Write the pack data to bundle_fd */
static int write_pack_data(int bundle_fd, struct rev_info *revs, struct strvec *pack_options)
{
struct child_process pack_objects = CHILD_PROCESS_INIT;
int i;
strvec_pushl(&pack_objects.args,
"pack-objects",
"--stdout", "--thin", "--delta-base-offset",
NULL);
strvec_pushv(&pack_objects.args, pack_options->v);
pack_objects.in = -1;
pack_objects.out = bundle_fd;
pack_objects.git_cmd = 1;
/*
* start_command() will close our descriptor if it's >1. Duplicate it
* to avoid surprising the caller.
*/
if (pack_objects.out > 1) {
pack_objects.out = dup(pack_objects.out);
if (pack_objects.out < 0) {
error_errno(_("unable to dup bundle descriptor"));
child_process_clear(&pack_objects);
return -1;
}
}
if (start_command(&pack_objects))
return error(_("Could not spawn pack-objects"));
for (i = 0; i < revs->pending.nr; i++) {
struct object *object = revs->pending.objects[i].item;
if (object->flags & UNINTERESTING)
write_or_die(pack_objects.in, "^", 1);
write_or_die(pack_objects.in, oid_to_hex(&object->oid), the_hash_algo->hexsz);
write_or_die(pack_objects.in, "\n", 1);
}
close(pack_objects.in);
if (finish_command(&pack_objects))
return error(_("pack-objects died"));
return 0;
}
/*
* Write out bundle refs based on the tips already
* parsed into revs.pending. As a side effect, may
* manipulate revs.pending to include additional
* necessary objects (like tags).
*
* Returns the number of refs written, or negative
* on error.
*/
static int write_bundle_refs(int bundle_fd, struct rev_info *revs)
{
int i;
int ref_count = 0;
for (i = 0; i < revs->pending.nr; i++) {
struct object_array_entry *e = revs->pending.objects + i;
struct object_id oid;
char *ref;
const char *display_ref;
int flag;
if (e->item->flags & UNINTERESTING)
continue;
if (dwim_ref(e->name, strlen(e->name), &oid, &ref, 0) != 1)
goto skip_write_ref;
if (read_ref_full(e->name, RESOLVE_REF_READING, &oid, &flag))
flag = 0;
display_ref = (flag & REF_ISSYMREF) ? e->name : ref;
if (e->item->type == OBJ_TAG &&
!is_tag_in_date_range(e->item, revs)) {
e->item->flags |= UNINTERESTING;
goto skip_write_ref;
}
/*
* Make sure the refs we wrote out is correct; --max-count and
* other limiting options could have prevented all the tips
* from getting output.
*
* Non commit objects such as tags and blobs do not have
* this issue as they are not affected by those extra
* constraints.
*/
if (!(e->item->flags & SHOWN) && e->item->type == OBJ_COMMIT) {
warning(_("ref '%s' is excluded by the rev-list options"),
e->name);
goto skip_write_ref;
}
/*
* If you run "git bundle create bndl v1.0..v2.0", the
* name of the positive ref is "v2.0" but that is the
* commit that is referenced by the tag, and not the tag
* itself.
*/
if (!oideq(&oid, &e->item->oid)) {
/*
* Is this the positive end of a range expressed
* in terms of a tag (e.g. v2.0 from the range
* "v1.0..v2.0")?
*/
struct commit *one = lookup_commit_reference(revs->repo, &oid);
struct object *obj;
if (e->item == &(one->object)) {
/*
* Need to include e->name as an
* independent ref to the pack-objects
* input, so that the tag is included
* in the output; otherwise we would
* end up triggering "empty bundle"
* error.
*/
obj = parse_object_or_die(&oid, e->name);
obj->flags |= SHOWN;
add_pending_object(revs, obj, e->name);
}
goto skip_write_ref;
}
ref_count++;
write_or_die(bundle_fd, oid_to_hex(&e->item->oid), the_hash_algo->hexsz);
write_or_die(bundle_fd, " ", 1);
write_or_die(bundle_fd, display_ref, strlen(display_ref));
write_or_die(bundle_fd, "\n", 1);
skip_write_ref:
free(ref);
}
/* end header */
write_or_die(bundle_fd, "\n", 1);
return ref_count;
}
struct bundle_prerequisites_info {
struct object_array *pending;
int fd;
};
static void write_bundle_prerequisites(struct commit *commit, void *data)
{
struct bundle_prerequisites_info *bpi = data;
struct object *object;
struct pretty_print_context ctx = { 0 };
struct strbuf buf = STRBUF_INIT;
if (!(commit->object.flags & BOUNDARY))
return;
strbuf_addf(&buf, "-%s ", oid_to_hex(&commit->object.oid));
write_or_die(bpi->fd, buf.buf, buf.len);
ctx.fmt = CMIT_FMT_ONELINE;
ctx.output_encoding = get_log_output_encoding();
strbuf_reset(&buf);
pretty_print_commit(&ctx, commit, &buf);
strbuf_trim(&buf);
object = (struct object *)commit;
object->flags |= UNINTERESTING;
add_object_array_with_path(object, buf.buf, bpi->pending, S_IFINVALID,
NULL);
strbuf_addch(&buf, '\n');
write_or_die(bpi->fd, buf.buf, buf.len);
strbuf_release(&buf);
}
int create_bundle(struct repository *r, const char *path,
int argc, const char **argv, struct strvec *pack_options, int version)
{
struct lock_file lock = LOCK_INIT;
int bundle_fd = -1;
int bundle_to_stdout;
int ref_count = 0;
struct rev_info revs, revs_copy;
int min_version = the_hash_algo == &hash_algos[GIT_HASH_SHA1] ? 2 : 3;
struct bundle_prerequisites_info bpi;
int i;
bundle_to_stdout = !strcmp(path, "-");
if (bundle_to_stdout)
bundle_fd = 1;
else
bundle_fd = hold_lock_file_for_update(&lock, path,
LOCK_DIE_ON_ERROR);
if (version == -1)
version = min_version;
if (version < 2 || version > 3) {
die(_("unsupported bundle version %d"), version);
} else if (version < min_version) {
die(_("cannot write bundle version %d with algorithm %s"), version, the_hash_algo->name);
} else if (version == 2) {
write_or_die(bundle_fd, v2_bundle_signature, strlen(v2_bundle_signature));
} else {
const char *capability = "@object-format=";
write_or_die(bundle_fd, v3_bundle_signature, strlen(v3_bundle_signature));
write_or_die(bundle_fd, capability, strlen(capability));
write_or_die(bundle_fd, the_hash_algo->name, strlen(the_hash_algo->name));
write_or_die(bundle_fd, "\n", 1);
}
/* init revs to list objects for pack-objects later */
save_commit_buffer = 0;
repo_init_revisions(r, &revs, NULL);
argc = setup_revisions(argc, argv, &revs, NULL);
if (argc > 1) {
error(_("unrecognized argument: %s"), argv[1]);
goto err;
}
/* save revs.pending in revs_copy for later use */
memcpy(&revs_copy, &revs, sizeof(revs));
revs_copy.pending.nr = 0;
revs_copy.pending.alloc = 0;
revs_copy.pending.objects = NULL;
for (i = 0; i < revs.pending.nr; i++) {
struct object_array_entry *e = revs.pending.objects + i;
if (e)
add_object_array_with_path(e->item, e->name,
&revs_copy.pending,
e->mode, e->path);
}
/* write prerequisites */
revs.boundary = 1;
if (prepare_revision_walk(&revs))
die("revision walk setup failed");
bpi.fd = bundle_fd;
bpi.pending = &revs_copy.pending;
traverse_commit_list(&revs, write_bundle_prerequisites, NULL, &bpi);
object_array_remove_duplicates(&revs_copy.pending);
/* write bundle refs */
ref_count = write_bundle_refs(bundle_fd, &revs_copy);
if (!ref_count)
die(_("Refusing to create empty bundle."));
else if (ref_count < 0)
goto err;
/* write pack */
if (write_pack_data(bundle_fd, &revs_copy, pack_options))
goto err;
if (!bundle_to_stdout) {
if (commit_lock_file(&lock))
die_errno(_("cannot create '%s'"), path);
}
return 0;
err:
rollback_lock_file(&lock);
return -1;
}
int unbundle(struct repository *r, struct bundle_header *header,
int bundle_fd, int flags)
{
const char *argv_index_pack[] = {"index-pack",
"--fix-thin", "--stdin", NULL, NULL};
struct child_process ip = CHILD_PROCESS_INIT;
if (flags & BUNDLE_VERBOSE)
argv_index_pack[3] = "-v";
if (verify_bundle(r, header, 0))
return -1;
ip.argv = argv_index_pack;
ip.in = bundle_fd;
ip.no_stdout = 1;
ip.git_cmd = 1;
if (run_command(&ip))
return error(_("index-pack died"));
return 0;
}