git/connected.c
Jonathan Tan 9da69a6539 fetch-pack: support more than one pack lockfile
Whenever a fetch results in a packfile being downloaded, a .keep file is
generated, so that the packfile can be preserved (from, say, a running
"git repack") until refs are written referring to the contents of the
packfile.

In a subsequent patch, a successful fetch using protocol v2 may result
in more than one .keep file being generated. Therefore, teach
fetch_pack() and the transport mechanism to support multiple .keep
files.

Implementation notes:

 - builtin/fetch-pack.c normally does not generate .keep files, and thus
   is unaffected by this or future changes. However, it has an
   undocumented "--lock-pack" feature, used by remote-curl.c when
   implementing the "fetch" remote helper command. In keeping with the
   remote helper protocol, only one "lock" line will ever be written;
   the rest will result in warnings to stderr. However, in practice,
   warnings will never be written because the remote-curl.c "fetch" is
   only used for protocol v0/v1 (which will not generate multiple .keep
   files). (Protocol v2 uses the "stateless-connect" command, not the
   "fetch" command.)

 - connected.c has an optimization in that connectivity checks on a ref
   need not be done if the target object is in a pack known to be
   self-contained and connected. If there are multiple packfiles, this
   optimization can no longer be done.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-10 18:06:34 -07:00

153 lines
4.4 KiB
C

#include "cache.h"
#include "object-store.h"
#include "run-command.h"
#include "sigchain.h"
#include "connected.h"
#include "transport.h"
#include "packfile.h"
#include "promisor-remote.h"
/*
* If we feed all the commits we want to verify to this command
*
* $ git rev-list --objects --stdin --not --all
*
* and if it does not error out, that means everything reachable from
* these commits locally exists and is connected to our existing refs.
* Note that this does _not_ validate the individual objects.
*
* Returns 0 if everything is connected, non-zero otherwise.
*/
int check_connected(oid_iterate_fn fn, void *cb_data,
struct check_connected_options *opt)
{
struct child_process rev_list = CHILD_PROCESS_INIT;
struct check_connected_options defaults = CHECK_CONNECTED_INIT;
char commit[GIT_MAX_HEXSZ + 1];
struct object_id oid;
int err = 0;
struct packed_git *new_pack = NULL;
struct transport *transport;
size_t base_len;
const unsigned hexsz = the_hash_algo->hexsz;
if (!opt)
opt = &defaults;
transport = opt->transport;
if (fn(cb_data, &oid)) {
if (opt->err_fd)
close(opt->err_fd);
return err;
}
if (transport && transport->smart_options &&
transport->smart_options->self_contained_and_connected &&
transport->pack_lockfiles.nr == 1 &&
strip_suffix(transport->pack_lockfiles.items[0].string,
".keep", &base_len)) {
struct strbuf idx_file = STRBUF_INIT;
strbuf_add(&idx_file, transport->pack_lockfiles.items[0].string,
base_len);
strbuf_addstr(&idx_file, ".idx");
new_pack = add_packed_git(idx_file.buf, idx_file.len, 1);
strbuf_release(&idx_file);
}
if (has_promisor_remote()) {
/*
* For partial clones, we don't want to have to do a regular
* connectivity check because we have to enumerate and exclude
* all promisor objects (slow), and then the connectivity check
* itself becomes a no-op because in a partial clone every
* object is a promisor object. Instead, just make sure we
* received, in a promisor packfile, the objects pointed to by
* each wanted ref.
*
* Before checking for promisor packs, be sure we have the
* latest pack-files loaded into memory.
*/
reprepare_packed_git(the_repository);
do {
struct packed_git *p;
for (p = get_all_packs(the_repository); p; p = p->next) {
if (!p->pack_promisor)
continue;
if (find_pack_entry_one(oid.hash, p))
goto promisor_pack_found;
}
/*
* Fallback to rev-list with oid and the rest of the
* object IDs provided by fn.
*/
goto no_promisor_pack_found;
promisor_pack_found:
;
} while (!fn(cb_data, &oid));
return 0;
}
no_promisor_pack_found:
if (opt->shallow_file) {
argv_array_push(&rev_list.args, "--shallow-file");
argv_array_push(&rev_list.args, opt->shallow_file);
}
argv_array_push(&rev_list.args,"rev-list");
argv_array_push(&rev_list.args, "--objects");
argv_array_push(&rev_list.args, "--stdin");
if (has_promisor_remote())
argv_array_push(&rev_list.args, "--exclude-promisor-objects");
if (!opt->is_deepening_fetch) {
argv_array_push(&rev_list.args, "--not");
argv_array_push(&rev_list.args, "--all");
}
argv_array_push(&rev_list.args, "--quiet");
argv_array_push(&rev_list.args, "--alternate-refs");
if (opt->progress)
argv_array_pushf(&rev_list.args, "--progress=%s",
_("Checking connectivity"));
rev_list.git_cmd = 1;
rev_list.env = opt->env;
rev_list.in = -1;
rev_list.no_stdout = 1;
if (opt->err_fd)
rev_list.err = opt->err_fd;
else
rev_list.no_stderr = opt->quiet;
if (start_command(&rev_list))
return error(_("Could not run 'git rev-list'"));
sigchain_push(SIGPIPE, SIG_IGN);
commit[hexsz] = '\n';
do {
/*
* If index-pack already checked that:
* - there are no dangling pointers in the new pack
* - the pack is self contained
* Then if the updated ref is in the new pack, then we
* are sure the ref is good and not sending it to
* rev-list for verification.
*/
if (new_pack && find_pack_entry_one(oid.hash, new_pack))
continue;
memcpy(commit, oid_to_hex(&oid), hexsz);
if (write_in_full(rev_list.in, commit, hexsz + 1) < 0) {
if (errno != EPIPE && errno != EINVAL)
error_errno(_("failed write to rev-list"));
err = -1;
break;
}
} while (!fn(cb_data, &oid));
if (close(rev_list.in))
err = error_errno(_("failed to close rev-list's stdin"));
sigchain_pop(SIGPIPE);
return finish_command(&rev_list) || err;
}