git/fetch-pack.c

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C
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#include "cache.h"
#include "lockfile.h"
#include "refs.h"
#include "pkt-line.h"
#include "commit.h"
#include "tag.h"
#include "exec_cmd.h"
#include "pack.h"
#include "sideband.h"
#include "fetch-pack.h"
#include "remote.h"
#include "run-command.h"
#include "connect.h"
#include "transport.h"
#include "version.h"
fetch-pack: avoid quadratic behavior in rev_list_push When we call find_common to start finding common ancestors with the remote side of a fetch, the first thing we do is insert the tip of each ref into our rev_list linked list. We keep the list sorted the whole time with commit_list_insert_by_date, which means our insertion ends up doing O(n^2) timestamp comparisons. We could teach rev_list_push to use an unsorted list, and then sort it once after we have added each ref. However, in get_rev, we process the list by popping commits off the front and adding parents back in timestamp-sorted order. So that procedure would still operate on the large list. Instead, we can replace the linked list with a heap-based priority queue, which can do O(log n) insertion, making the whole insertion procedure O(n log n). As a result of switching to the prio_queue struct, we fix two minor bugs: 1. When we "pop" a commit in get_rev, and when we clear the rev_list in find_common, we do not take care to free the "struct commit_list", and just leak its memory. With the prio_queue implementation, the memory management is handled for us. 2. In get_rev, we look at the head commit of the list, possibly push its parents onto the list, and then "pop" the front of the list off, assuming it is the same element that we just peeked at. This is typically going to be the case, but would not be in the face of clock skew: the parents are inserted by date, and could potentially be inserted at the head of the list if they have a timestamp newer than their descendent. In this case, we would accidentally pop the parent, and never process it at all. The new implementation pulls the commit off of the queue as we examine it, and so does not suffer from this problem. With this patch, a fetch of a single commit into a repository with 50,000 refs went from: real 0m7.984s user 0m7.852s sys 0m0.120s to: real 0m2.017s user 0m1.884s sys 0m0.124s Before this patch, a larger case with 370K refs still had not completed after tens of minutes; with this patch, it completes in about 12 seconds. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-02 10:24:21 +04:00
#include "prio-queue.h"
#include "sha1-array.h"
#include "sigchain.h"
static int transfer_unpack_limit = -1;
static int fetch_unpack_limit = -1;
static int unpack_limit = 100;
static int prefer_ofs_delta = 1;
static int no_done;
static int fetch_fsck_objects = -1;
static int transfer_fsck_objects = -1;
static int agent_supported;
static struct lock_file shallow_lock;
static const char *alternate_shallow_file;
/* Remember to update object flag allocation in object.h */
#define COMPLETE (1U << 0)
#define COMMON (1U << 1)
#define COMMON_REF (1U << 2)
#define SEEN (1U << 3)
#define POPPED (1U << 4)
static int marked;
/*
* After sending this many "have"s if we do not get any new ACK , we
* give up traversing our history.
*/
#define MAX_IN_VAIN 256
fetch-pack: avoid quadratic behavior in rev_list_push When we call find_common to start finding common ancestors with the remote side of a fetch, the first thing we do is insert the tip of each ref into our rev_list linked list. We keep the list sorted the whole time with commit_list_insert_by_date, which means our insertion ends up doing O(n^2) timestamp comparisons. We could teach rev_list_push to use an unsorted list, and then sort it once after we have added each ref. However, in get_rev, we process the list by popping commits off the front and adding parents back in timestamp-sorted order. So that procedure would still operate on the large list. Instead, we can replace the linked list with a heap-based priority queue, which can do O(log n) insertion, making the whole insertion procedure O(n log n). As a result of switching to the prio_queue struct, we fix two minor bugs: 1. When we "pop" a commit in get_rev, and when we clear the rev_list in find_common, we do not take care to free the "struct commit_list", and just leak its memory. With the prio_queue implementation, the memory management is handled for us. 2. In get_rev, we look at the head commit of the list, possibly push its parents onto the list, and then "pop" the front of the list off, assuming it is the same element that we just peeked at. This is typically going to be the case, but would not be in the face of clock skew: the parents are inserted by date, and could potentially be inserted at the head of the list if they have a timestamp newer than their descendent. In this case, we would accidentally pop the parent, and never process it at all. The new implementation pulls the commit off of the queue as we examine it, and so does not suffer from this problem. With this patch, a fetch of a single commit into a repository with 50,000 refs went from: real 0m7.984s user 0m7.852s sys 0m0.120s to: real 0m2.017s user 0m1.884s sys 0m0.124s Before this patch, a larger case with 370K refs still had not completed after tens of minutes; with this patch, it completes in about 12 seconds. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-02 10:24:21 +04:00
static struct prio_queue rev_list = { compare_commits_by_commit_date };
static int non_common_revs, multi_ack, use_sideband;
/* Allow specifying sha1 if it is a ref tip. */
#define ALLOW_TIP_SHA1 01
/* Allow request of a sha1 if it is reachable from a ref (possibly hidden ref). */
#define ALLOW_REACHABLE_SHA1 02
static unsigned int allow_unadvertised_object_request;
static void rev_list_push(struct commit *commit, int mark)
{
if (!(commit->object.flags & mark)) {
commit->object.flags |= mark;
if (parse_commit(commit))
return;
fetch-pack: avoid quadratic behavior in rev_list_push When we call find_common to start finding common ancestors with the remote side of a fetch, the first thing we do is insert the tip of each ref into our rev_list linked list. We keep the list sorted the whole time with commit_list_insert_by_date, which means our insertion ends up doing O(n^2) timestamp comparisons. We could teach rev_list_push to use an unsorted list, and then sort it once after we have added each ref. However, in get_rev, we process the list by popping commits off the front and adding parents back in timestamp-sorted order. So that procedure would still operate on the large list. Instead, we can replace the linked list with a heap-based priority queue, which can do O(log n) insertion, making the whole insertion procedure O(n log n). As a result of switching to the prio_queue struct, we fix two minor bugs: 1. When we "pop" a commit in get_rev, and when we clear the rev_list in find_common, we do not take care to free the "struct commit_list", and just leak its memory. With the prio_queue implementation, the memory management is handled for us. 2. In get_rev, we look at the head commit of the list, possibly push its parents onto the list, and then "pop" the front of the list off, assuming it is the same element that we just peeked at. This is typically going to be the case, but would not be in the face of clock skew: the parents are inserted by date, and could potentially be inserted at the head of the list if they have a timestamp newer than their descendent. In this case, we would accidentally pop the parent, and never process it at all. The new implementation pulls the commit off of the queue as we examine it, and so does not suffer from this problem. With this patch, a fetch of a single commit into a repository with 50,000 refs went from: real 0m7.984s user 0m7.852s sys 0m0.120s to: real 0m2.017s user 0m1.884s sys 0m0.124s Before this patch, a larger case with 370K refs still had not completed after tens of minutes; with this patch, it completes in about 12 seconds. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-02 10:24:21 +04:00
prio_queue_put(&rev_list, commit);
if (!(commit->object.flags & COMMON))
non_common_revs++;
}
}
static int rev_list_insert_ref(const char *refname, const unsigned char *sha1)
{
struct object *o = deref_tag(parse_object(sha1), refname, 0);
if (o && o->type == OBJ_COMMIT)
rev_list_push((struct commit *)o, SEEN);
return 0;
}
static int rev_list_insert_ref_oid(const char *refname, const struct object_id *oid,
int flag, void *cb_data)
{
return rev_list_insert_ref(refname, oid->hash);
}
static int clear_marks(const char *refname, const struct object_id *oid,
int flag, void *cb_data)
{
struct object *o = deref_tag(parse_object(oid->hash), refname, 0);
if (o && o->type == OBJ_COMMIT)
clear_commit_marks((struct commit *)o,
COMMON | COMMON_REF | SEEN | POPPED);
return 0;
}
/*
This function marks a rev and its ancestors as common.
In some cases, it is desirable to mark only the ancestors (for example
when only the server does not yet know that they are common).
*/
static void mark_common(struct commit *commit,
int ancestors_only, int dont_parse)
{
if (commit != NULL && !(commit->object.flags & COMMON)) {
struct object *o = (struct object *)commit;
if (!ancestors_only)
o->flags |= COMMON;
if (!(o->flags & SEEN))
rev_list_push(commit, SEEN);
else {
struct commit_list *parents;
if (!ancestors_only && !(o->flags & POPPED))
non_common_revs--;
if (!o->parsed && !dont_parse)
if (parse_commit(commit))
return;
for (parents = commit->parents;
parents;
parents = parents->next)
mark_common(parents->item, 0, dont_parse);
}
}
}
/*
Get the next rev to send, ignoring the common.
*/
static const unsigned char *get_rev(void)
{
struct commit *commit = NULL;
while (commit == NULL) {
unsigned int mark;
struct commit_list *parents;
fetch-pack: avoid quadratic behavior in rev_list_push When we call find_common to start finding common ancestors with the remote side of a fetch, the first thing we do is insert the tip of each ref into our rev_list linked list. We keep the list sorted the whole time with commit_list_insert_by_date, which means our insertion ends up doing O(n^2) timestamp comparisons. We could teach rev_list_push to use an unsorted list, and then sort it once after we have added each ref. However, in get_rev, we process the list by popping commits off the front and adding parents back in timestamp-sorted order. So that procedure would still operate on the large list. Instead, we can replace the linked list with a heap-based priority queue, which can do O(log n) insertion, making the whole insertion procedure O(n log n). As a result of switching to the prio_queue struct, we fix two minor bugs: 1. When we "pop" a commit in get_rev, and when we clear the rev_list in find_common, we do not take care to free the "struct commit_list", and just leak its memory. With the prio_queue implementation, the memory management is handled for us. 2. In get_rev, we look at the head commit of the list, possibly push its parents onto the list, and then "pop" the front of the list off, assuming it is the same element that we just peeked at. This is typically going to be the case, but would not be in the face of clock skew: the parents are inserted by date, and could potentially be inserted at the head of the list if they have a timestamp newer than their descendent. In this case, we would accidentally pop the parent, and never process it at all. The new implementation pulls the commit off of the queue as we examine it, and so does not suffer from this problem. With this patch, a fetch of a single commit into a repository with 50,000 refs went from: real 0m7.984s user 0m7.852s sys 0m0.120s to: real 0m2.017s user 0m1.884s sys 0m0.124s Before this patch, a larger case with 370K refs still had not completed after tens of minutes; with this patch, it completes in about 12 seconds. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-02 10:24:21 +04:00
if (rev_list.nr == 0 || non_common_revs == 0)
return NULL;
fetch-pack: avoid quadratic behavior in rev_list_push When we call find_common to start finding common ancestors with the remote side of a fetch, the first thing we do is insert the tip of each ref into our rev_list linked list. We keep the list sorted the whole time with commit_list_insert_by_date, which means our insertion ends up doing O(n^2) timestamp comparisons. We could teach rev_list_push to use an unsorted list, and then sort it once after we have added each ref. However, in get_rev, we process the list by popping commits off the front and adding parents back in timestamp-sorted order. So that procedure would still operate on the large list. Instead, we can replace the linked list with a heap-based priority queue, which can do O(log n) insertion, making the whole insertion procedure O(n log n). As a result of switching to the prio_queue struct, we fix two minor bugs: 1. When we "pop" a commit in get_rev, and when we clear the rev_list in find_common, we do not take care to free the "struct commit_list", and just leak its memory. With the prio_queue implementation, the memory management is handled for us. 2. In get_rev, we look at the head commit of the list, possibly push its parents onto the list, and then "pop" the front of the list off, assuming it is the same element that we just peeked at. This is typically going to be the case, but would not be in the face of clock skew: the parents are inserted by date, and could potentially be inserted at the head of the list if they have a timestamp newer than their descendent. In this case, we would accidentally pop the parent, and never process it at all. The new implementation pulls the commit off of the queue as we examine it, and so does not suffer from this problem. With this patch, a fetch of a single commit into a repository with 50,000 refs went from: real 0m7.984s user 0m7.852s sys 0m0.120s to: real 0m2.017s user 0m1.884s sys 0m0.124s Before this patch, a larger case with 370K refs still had not completed after tens of minutes; with this patch, it completes in about 12 seconds. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-02 10:24:21 +04:00
commit = prio_queue_get(&rev_list);
parse_commit(commit);
parents = commit->parents;
commit->object.flags |= POPPED;
if (!(commit->object.flags & COMMON))
non_common_revs--;
if (commit->object.flags & COMMON) {
/* do not send "have", and ignore ancestors */
commit = NULL;
mark = COMMON | SEEN;
} else if (commit->object.flags & COMMON_REF)
/* send "have", and ignore ancestors */
mark = COMMON | SEEN;
else
/* send "have", also for its ancestors */
mark = SEEN;
while (parents) {
if (!(parents->item->object.flags & SEEN))
rev_list_push(parents->item, mark);
if (mark & COMMON)
mark_common(parents->item, 1, 0);
parents = parents->next;
}
}
return commit->object.oid.hash;
}
enum ack_type {
NAK = 0,
ACK,
ACK_continue,
ACK_common,
ACK_ready
};
static void consume_shallow_list(struct fetch_pack_args *args, int fd)
{
if (args->stateless_rpc && args->depth > 0) {
/* If we sent a depth we will get back "duplicate"
* shallow and unshallow commands every time there
* is a block of have lines exchanged.
*/
pkt-line: provide a LARGE_PACKET_MAX static buffer Most of the callers of packet_read_line just read into a static 1000-byte buffer (callers which handle arbitrary binary data already use LARGE_PACKET_MAX). This works fine in practice, because: 1. The only variable-sized data in these lines is a ref name, and refs tend to be a lot shorter than 1000 characters. 2. When sending ref lines, git-core always limits itself to 1000 byte packets. However, the only limit given in the protocol specification in Documentation/technical/protocol-common.txt is LARGE_PACKET_MAX; the 1000 byte limit is mentioned only in pack-protocol.txt, and then only describing what we write, not as a specific limit for readers. This patch lets us bump the 1000-byte limit to LARGE_PACKET_MAX. Even though git-core will never write a packet where this makes a difference, there are two good reasons to do this: 1. Other git implementations may have followed protocol-common.txt and used a larger maximum size. We don't bump into it in practice because it would involve very long ref names. 2. We may want to increase the 1000-byte limit one day. Since packets are transferred before any capabilities, it's difficult to do this in a backwards-compatible way. But if we bump the size of buffer the readers can handle, eventually older versions of git will be obsolete enough that we can justify bumping the writers, as well. We don't have plans to do this anytime soon, but there is no reason not to start the clock ticking now. Just bumping all of the reading bufs to LARGE_PACKET_MAX would waste memory. Instead, since most readers just read into a temporary buffer anyway, let's provide a single static buffer that all callers can use. We can further wrap this detail away by having the packet_read_line wrapper just use the buffer transparently and return a pointer to the static storage. That covers most of the cases, and the remaining ones already read into their own LARGE_PACKET_MAX buffers. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-21 00:02:57 +04:00
char *line;
while ((line = packet_read_line(fd, NULL))) {
if (starts_with(line, "shallow "))
continue;
if (starts_with(line, "unshallow "))
continue;
die("git fetch-pack: expected shallow list");
}
}
}
static enum ack_type get_ack(int fd, unsigned char *result_sha1)
{
pkt-line: provide a LARGE_PACKET_MAX static buffer Most of the callers of packet_read_line just read into a static 1000-byte buffer (callers which handle arbitrary binary data already use LARGE_PACKET_MAX). This works fine in practice, because: 1. The only variable-sized data in these lines is a ref name, and refs tend to be a lot shorter than 1000 characters. 2. When sending ref lines, git-core always limits itself to 1000 byte packets. However, the only limit given in the protocol specification in Documentation/technical/protocol-common.txt is LARGE_PACKET_MAX; the 1000 byte limit is mentioned only in pack-protocol.txt, and then only describing what we write, not as a specific limit for readers. This patch lets us bump the 1000-byte limit to LARGE_PACKET_MAX. Even though git-core will never write a packet where this makes a difference, there are two good reasons to do this: 1. Other git implementations may have followed protocol-common.txt and used a larger maximum size. We don't bump into it in practice because it would involve very long ref names. 2. We may want to increase the 1000-byte limit one day. Since packets are transferred before any capabilities, it's difficult to do this in a backwards-compatible way. But if we bump the size of buffer the readers can handle, eventually older versions of git will be obsolete enough that we can justify bumping the writers, as well. We don't have plans to do this anytime soon, but there is no reason not to start the clock ticking now. Just bumping all of the reading bufs to LARGE_PACKET_MAX would waste memory. Instead, since most readers just read into a temporary buffer anyway, let's provide a single static buffer that all callers can use. We can further wrap this detail away by having the packet_read_line wrapper just use the buffer transparently and return a pointer to the static storage. That covers most of the cases, and the remaining ones already read into their own LARGE_PACKET_MAX buffers. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-21 00:02:57 +04:00
int len;
char *line = packet_read_line(fd, &len);
const char *arg;
if (!len)
die("git fetch-pack: expected ACK/NAK, got EOF");
if (!strcmp(line, "NAK"))
return NAK;
if (skip_prefix(line, "ACK ", &arg)) {
if (!get_sha1_hex(arg, result_sha1)) {
arg += 40;
len -= arg - line;
if (len < 1)
return ACK;
if (strstr(arg, "continue"))
return ACK_continue;
if (strstr(arg, "common"))
return ACK_common;
if (strstr(arg, "ready"))
return ACK_ready;
return ACK;
}
}
die("git fetch_pack: expected ACK/NAK, got '%s'", line);
}
static void send_request(struct fetch_pack_args *args,
int fd, struct strbuf *buf)
{
if (args->stateless_rpc) {
send_sideband(fd, -1, buf->buf, buf->len, LARGE_PACKET_MAX);
packet_flush(fd);
} else
write_or_die(fd, buf->buf, buf->len);
}
static void insert_one_alternate_ref(const struct ref *ref, void *unused)
{
rev_list_insert_ref(NULL, ref->old_oid.hash);
}
#define INITIAL_FLUSH 16
#define PIPESAFE_FLUSH 32
#define LARGE_FLUSH 1024
static int next_flush(struct fetch_pack_args *args, int count)
{
int flush_limit = args->stateless_rpc ? LARGE_FLUSH : PIPESAFE_FLUSH;
if (count < flush_limit)
count <<= 1;
else
count += flush_limit;
return count;
}
static int find_common(struct fetch_pack_args *args,
int fd[2], unsigned char *result_sha1,
struct ref *refs)
{
int fetching;
int count = 0, flushes = 0, flush_at = INITIAL_FLUSH, retval;
const unsigned char *sha1;
unsigned in_vain = 0;
int got_continue = 0;
int got_ready = 0;
struct strbuf req_buf = STRBUF_INIT;
size_t state_len = 0;
if (args->stateless_rpc && multi_ack == 1)
die("--stateless-rpc requires multi_ack_detailed");
if (marked)
for_each_ref(clear_marks, NULL);
marked = 1;
for_each_ref(rev_list_insert_ref_oid, NULL);
for_each_alternate_ref(insert_one_alternate_ref, NULL);
fetching = 0;
for ( ; refs ; refs = refs->next) {
unsigned char *remote = refs->old_oid.hash;
const char *remote_hex;
struct object *o;
/*
* If that object is complete (i.e. it is an ancestor of a
* local ref), we tell them we have it but do not have to
* tell them about its ancestors, which they already know
* about.
*
* We use lookup_object here because we are only
* interested in the case we *know* the object is
* reachable and we have already scanned it.
*/
if (((o = lookup_object(remote)) != NULL) &&
(o->flags & COMPLETE)) {
continue;
}
remote_hex = sha1_to_hex(remote);
if (!fetching) {
struct strbuf c = STRBUF_INIT;
if (multi_ack == 2) strbuf_addstr(&c, " multi_ack_detailed");
if (multi_ack == 1) strbuf_addstr(&c, " multi_ack");
if (no_done) strbuf_addstr(&c, " no-done");
if (use_sideband == 2) strbuf_addstr(&c, " side-band-64k");
if (use_sideband == 1) strbuf_addstr(&c, " side-band");
if (args->use_thin_pack) strbuf_addstr(&c, " thin-pack");
if (args->no_progress) strbuf_addstr(&c, " no-progress");
if (args->include_tag) strbuf_addstr(&c, " include-tag");
if (prefer_ofs_delta) strbuf_addstr(&c, " ofs-delta");
if (agent_supported) strbuf_addf(&c, " agent=%s",
git_user_agent_sanitized());
packet_buf_write(&req_buf, "want %s%s\n", remote_hex, c.buf);
strbuf_release(&c);
} else
packet_buf_write(&req_buf, "want %s\n", remote_hex);
fetching++;
}
if (!fetching) {
strbuf_release(&req_buf);
packet_flush(fd[1]);
return 1;
}
if (is_repository_shallow())
write_shallow_commits(&req_buf, 1, NULL);
if (args->depth > 0)
packet_buf_write(&req_buf, "deepen %d", args->depth);
packet_buf_flush(&req_buf);
state_len = req_buf.len;
if (args->depth > 0) {
pkt-line: provide a LARGE_PACKET_MAX static buffer Most of the callers of packet_read_line just read into a static 1000-byte buffer (callers which handle arbitrary binary data already use LARGE_PACKET_MAX). This works fine in practice, because: 1. The only variable-sized data in these lines is a ref name, and refs tend to be a lot shorter than 1000 characters. 2. When sending ref lines, git-core always limits itself to 1000 byte packets. However, the only limit given in the protocol specification in Documentation/technical/protocol-common.txt is LARGE_PACKET_MAX; the 1000 byte limit is mentioned only in pack-protocol.txt, and then only describing what we write, not as a specific limit for readers. This patch lets us bump the 1000-byte limit to LARGE_PACKET_MAX. Even though git-core will never write a packet where this makes a difference, there are two good reasons to do this: 1. Other git implementations may have followed protocol-common.txt and used a larger maximum size. We don't bump into it in practice because it would involve very long ref names. 2. We may want to increase the 1000-byte limit one day. Since packets are transferred before any capabilities, it's difficult to do this in a backwards-compatible way. But if we bump the size of buffer the readers can handle, eventually older versions of git will be obsolete enough that we can justify bumping the writers, as well. We don't have plans to do this anytime soon, but there is no reason not to start the clock ticking now. Just bumping all of the reading bufs to LARGE_PACKET_MAX would waste memory. Instead, since most readers just read into a temporary buffer anyway, let's provide a single static buffer that all callers can use. We can further wrap this detail away by having the packet_read_line wrapper just use the buffer transparently and return a pointer to the static storage. That covers most of the cases, and the remaining ones already read into their own LARGE_PACKET_MAX buffers. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-21 00:02:57 +04:00
char *line;
const char *arg;
unsigned char sha1[20];
send_request(args, fd[1], &req_buf);
pkt-line: provide a LARGE_PACKET_MAX static buffer Most of the callers of packet_read_line just read into a static 1000-byte buffer (callers which handle arbitrary binary data already use LARGE_PACKET_MAX). This works fine in practice, because: 1. The only variable-sized data in these lines is a ref name, and refs tend to be a lot shorter than 1000 characters. 2. When sending ref lines, git-core always limits itself to 1000 byte packets. However, the only limit given in the protocol specification in Documentation/technical/protocol-common.txt is LARGE_PACKET_MAX; the 1000 byte limit is mentioned only in pack-protocol.txt, and then only describing what we write, not as a specific limit for readers. This patch lets us bump the 1000-byte limit to LARGE_PACKET_MAX. Even though git-core will never write a packet where this makes a difference, there are two good reasons to do this: 1. Other git implementations may have followed protocol-common.txt and used a larger maximum size. We don't bump into it in practice because it would involve very long ref names. 2. We may want to increase the 1000-byte limit one day. Since packets are transferred before any capabilities, it's difficult to do this in a backwards-compatible way. But if we bump the size of buffer the readers can handle, eventually older versions of git will be obsolete enough that we can justify bumping the writers, as well. We don't have plans to do this anytime soon, but there is no reason not to start the clock ticking now. Just bumping all of the reading bufs to LARGE_PACKET_MAX would waste memory. Instead, since most readers just read into a temporary buffer anyway, let's provide a single static buffer that all callers can use. We can further wrap this detail away by having the packet_read_line wrapper just use the buffer transparently and return a pointer to the static storage. That covers most of the cases, and the remaining ones already read into their own LARGE_PACKET_MAX buffers. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-21 00:02:57 +04:00
while ((line = packet_read_line(fd[0], NULL))) {
if (skip_prefix(line, "shallow ", &arg)) {
if (get_sha1_hex(arg, sha1))
die("invalid shallow line: %s", line);
register_shallow(sha1);
continue;
}
if (skip_prefix(line, "unshallow ", &arg)) {
if (get_sha1_hex(arg, sha1))
die("invalid unshallow line: %s", line);
if (!lookup_object(sha1))
die("object not found: %s", line);
/* make sure that it is parsed as shallow */
if (!parse_object(sha1))
die("error in object: %s", line);
if (unregister_shallow(sha1))
die("no shallow found: %s", line);
continue;
}
die("expected shallow/unshallow, got %s", line);
}
} else if (!args->stateless_rpc)
send_request(args, fd[1], &req_buf);
if (!args->stateless_rpc) {
/* If we aren't using the stateless-rpc interface
* we don't need to retain the headers.
*/
strbuf_setlen(&req_buf, 0);
state_len = 0;
}
flushes = 0;
retval = -1;
while ((sha1 = get_rev())) {
packet_buf_write(&req_buf, "have %s\n", sha1_to_hex(sha1));
if (args->verbose)
fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
in_vain++;
if (flush_at <= ++count) {
int ack;
packet_buf_flush(&req_buf);
send_request(args, fd[1], &req_buf);
strbuf_setlen(&req_buf, state_len);
flushes++;
flush_at = next_flush(args, count);
/*
* We keep one window "ahead" of the other side, and
* will wait for an ACK only on the next one
*/
if (!args->stateless_rpc && count == INITIAL_FLUSH)
continue;
consume_shallow_list(args, fd[0]);
do {
ack = get_ack(fd[0], result_sha1);
if (args->verbose && ack)
fprintf(stderr, "got ack %d %s\n", ack,
sha1_to_hex(result_sha1));
switch (ack) {
case ACK:
flushes = 0;
multi_ack = 0;
retval = 0;
goto done;
case ACK_common:
case ACK_ready:
case ACK_continue: {
struct commit *commit =
lookup_commit(result_sha1);
if (!commit)
die("invalid commit %s", sha1_to_hex(result_sha1));
if (args->stateless_rpc
&& ack == ACK_common
&& !(commit->object.flags & COMMON)) {
/* We need to replay the have for this object
* on the next RPC request so the peer knows
* it is in common with us.
*/
const char *hex = sha1_to_hex(result_sha1);
packet_buf_write(&req_buf, "have %s\n", hex);
state_len = req_buf.len;
}
mark_common(commit, 0, 1);
retval = 0;
in_vain = 0;
got_continue = 1;
if (ack == ACK_ready) {
fetch-pack: avoid quadratic behavior in rev_list_push When we call find_common to start finding common ancestors with the remote side of a fetch, the first thing we do is insert the tip of each ref into our rev_list linked list. We keep the list sorted the whole time with commit_list_insert_by_date, which means our insertion ends up doing O(n^2) timestamp comparisons. We could teach rev_list_push to use an unsorted list, and then sort it once after we have added each ref. However, in get_rev, we process the list by popping commits off the front and adding parents back in timestamp-sorted order. So that procedure would still operate on the large list. Instead, we can replace the linked list with a heap-based priority queue, which can do O(log n) insertion, making the whole insertion procedure O(n log n). As a result of switching to the prio_queue struct, we fix two minor bugs: 1. When we "pop" a commit in get_rev, and when we clear the rev_list in find_common, we do not take care to free the "struct commit_list", and just leak its memory. With the prio_queue implementation, the memory management is handled for us. 2. In get_rev, we look at the head commit of the list, possibly push its parents onto the list, and then "pop" the front of the list off, assuming it is the same element that we just peeked at. This is typically going to be the case, but would not be in the face of clock skew: the parents are inserted by date, and could potentially be inserted at the head of the list if they have a timestamp newer than their descendent. In this case, we would accidentally pop the parent, and never process it at all. The new implementation pulls the commit off of the queue as we examine it, and so does not suffer from this problem. With this patch, a fetch of a single commit into a repository with 50,000 refs went from: real 0m7.984s user 0m7.852s sys 0m0.120s to: real 0m2.017s user 0m1.884s sys 0m0.124s Before this patch, a larger case with 370K refs still had not completed after tens of minutes; with this patch, it completes in about 12 seconds. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-02 10:24:21 +04:00
clear_prio_queue(&rev_list);
got_ready = 1;
}
break;
}
}
} while (ack);
flushes--;
if (got_continue && MAX_IN_VAIN < in_vain) {
if (args->verbose)
fprintf(stderr, "giving up\n");
break; /* give up */
}
}
}
done:
if (!got_ready || !no_done) {
packet_buf_write(&req_buf, "done\n");
send_request(args, fd[1], &req_buf);
}
if (args->verbose)
fprintf(stderr, "done\n");
if (retval != 0) {
multi_ack = 0;
flushes++;
}
strbuf_release(&req_buf);
if (!got_ready || !no_done)
consume_shallow_list(args, fd[0]);
while (flushes || multi_ack) {
int ack = get_ack(fd[0], result_sha1);
if (ack) {
if (args->verbose)
fprintf(stderr, "got ack (%d) %s\n", ack,
sha1_to_hex(result_sha1));
if (ack == ACK)
return 0;
multi_ack = 1;
continue;
}
flushes--;
}
/* it is no error to fetch into a completely empty repo */
return count ? retval : 0;
}
static struct commit_list *complete;
static int mark_complete(const unsigned char *sha1)
{
struct object *o = parse_object(sha1);
while (o && o->type == OBJ_TAG) {
struct tag *t = (struct tag *) o;
if (!t->tagged)
break; /* broken repository */
o->flags |= COMPLETE;
o = parse_object(t->tagged->oid.hash);
}
if (o && o->type == OBJ_COMMIT) {
struct commit *commit = (struct commit *)o;
if (!(commit->object.flags & COMPLETE)) {
commit->object.flags |= COMPLETE;
commit_list_insert(commit, &complete);
}
}
return 0;
}
static int mark_complete_oid(const char *refname, const struct object_id *oid,
int flag, void *cb_data)
{
return mark_complete(oid->hash);
}
static void mark_recent_complete_commits(struct fetch_pack_args *args,
unsigned long cutoff)
{
while (complete && cutoff <= complete->item->date) {
if (args->verbose)
fprintf(stderr, "Marking %s as complete\n",
oid_to_hex(&complete->item->object.oid));
pop_most_recent_commit(&complete, COMPLETE);
}
}
static void filter_refs(struct fetch_pack_args *args,
struct ref **refs,
struct ref **sought, int nr_sought)
{
struct ref *newlist = NULL;
struct ref **newtail = &newlist;
struct ref *ref, *next;
int i;
i = 0;
for (ref = *refs; ref; ref = next) {
int keep = 0;
next = ref->next;
if (starts_with(ref->name, "refs/") &&
fetch-pack: do not filter out one-level refs Currently fetching a one-level ref like "refs/foo" does not work consistently. The outer "git fetch" program filters the list of refs, checking each against check_refname_format. Then it feeds the result to do_fetch_pack to actually negotiate the haves/wants and get the pack. The fetch-pack code does its own filter, and it behaves differently. The fetch-pack filter looks for refs in "refs/", and then feeds everything _after_ the slash (i.e., just "foo") into check_refname_format. But check_refname_format is not designed to look at a partial refname. It complains that the ref has only one component, thinking it is at the root (i.e., alongside "HEAD"), when in reality we just fed it a partial refname. As a result, we omit a ref like "refs/foo" from the pack request, even though "git fetch" then tries to store the resulting ref. If we happen to get the object anyway (e.g., because the ref is contained in another ref we are fetching), then the fetch succeeds. But if it is a unique object, we fail when trying to update "refs/foo". We can fix this by just passing the whole refname into check_refname_format; we know the part we were omitting is "refs/", which is acceptable in a refname. This at least makes the checks consistent with each other. This problem happens most commonly with "refs/stash", which is the only one-level ref in wide use. However, our test does not use "refs/stash", as we may later want to restrict it specifically (not because it is one-level, but because of the semantics of stashes). We may also want to do away with the multiple levels of filtering (which can cause problems when they are out of sync), or even forbid one-level refs entirely. However, those decisions can come later; this fixes the most immediate problem, which is the mismatch between the two. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-15 14:46:13 +04:00
check_refname_format(ref->name, 0))
; /* trash */
else {
while (i < nr_sought) {
int cmp = strcmp(ref->name, sought[i]->name);
if (cmp < 0)
break; /* definitely do not have it */
else if (cmp == 0) {
keep = 1; /* definitely have it */
sought[i]->matched = 1;
}
i++;
}
}
if (!keep && args->fetch_all &&
(!args->depth || !starts_with(ref->name, "refs/tags/")))
keep = 1;
if (keep) {
*newtail = ref;
ref->next = NULL;
newtail = &ref->next;
} else {
free(ref);
}
}
/* Append unmatched requests to the list */
if ((allow_unadvertised_object_request &
(ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1))) {
for (i = 0; i < nr_sought; i++) {
unsigned char sha1[20];
ref = sought[i];
if (ref->matched)
continue;
if (get_sha1_hex(ref->name, sha1) ||
ref->name[40] != '\0' ||
hashcmp(sha1, ref->old_oid.hash))
continue;
ref->matched = 1;
filter_ref: make a copy of extra "sought" entries If the server supports allow_tip_sha1_in_want, we add any unmatched raw-sha1 entries in our "sought" list of refs to the list of refs we will ask the other side for. We do so by inserting the original "struct ref" directly into our list, rather than making a copy. This has several problems. The most minor problem is that one cannot ever free the resulting list; it contains structs that are copies of the remote refs (made earlier by fetch_pack) along with sought refs that are referenced elsewhere. But more importantly that we set the ref->next pointer to NULL, chopping off the remainder of any existing list that the ref was a part of. We get the set of "sought" refs in an array rather than a linked list, but that array is often in turn generated from a list. The test modification in t5516 demonstrates this. Rather than fetching just an exact sha1, we fetch that sha1 plus another ref: - we build a linked list of refs to fetch when do_fetch calls get_ref_map; the exact sha1 is first, followed by the named ref ("refs/heads/extra" in this case). - we pass that linked list to transport_fetch_ref, which squashes it into an array of pointers - that array goes to fetch_pack, which calls filter_ref. There we generate the want list from a mix of what the remote side has advertised, and the "sought" entry for the exact sha1. We set the sought entry's "next" pointer to NULL. - after we return from transport_fetch_refs, we then try to update the refs by following the linked list. But our list is now truncated, and we do not update refs/heads/extra at all. We can fix this by making a copy of the ref. There's nothing that fetch_pack does to it that must be reflected in the original "sought" list (and indeed, if that were the case we would have a serious bug, because it is only exact-sha1 entries which are treated this way). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-03-19 23:37:09 +03:00
*newtail = copy_ref(ref);
newtail = &(*newtail)->next;
}
}
*refs = newlist;
}
static void mark_alternate_complete(const struct ref *ref, void *unused)
{
mark_complete(ref->old_oid.hash);
}
static int everything_local(struct fetch_pack_args *args,
struct ref **refs,
struct ref **sought, int nr_sought)
{
struct ref *ref;
int retval;
unsigned long cutoff = 0;
save_commit_buffer = 0;
for (ref = *refs; ref; ref = ref->next) {
struct object *o;
if (!has_object_file(&ref->old_oid))
continue;
o = parse_object(ref->old_oid.hash);
if (!o)
continue;
/* We already have it -- which may mean that we were
* in sync with the other side at some time after
* that (it is OK if we guess wrong here).
*/
if (o->type == OBJ_COMMIT) {
struct commit *commit = (struct commit *)o;
if (!cutoff || cutoff < commit->date)
cutoff = commit->date;
}
}
if (!args->depth) {
for_each_ref(mark_complete_oid, NULL);
for_each_alternate_ref(mark_alternate_complete, NULL);
commit_list_sort_by_date(&complete);
if (cutoff)
mark_recent_complete_commits(args, cutoff);
}
/*
* Mark all complete remote refs as common refs.
* Don't mark them common yet; the server has to be told so first.
*/
for (ref = *refs; ref; ref = ref->next) {
struct object *o = deref_tag(lookup_object(ref->old_oid.hash),
NULL, 0);
if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
continue;
if (!(o->flags & SEEN)) {
rev_list_push((struct commit *)o, COMMON_REF | SEEN);
mark_common((struct commit *)o, 1, 1);
}
}
filter_refs(args, refs, sought, nr_sought);
for (retval = 1, ref = *refs; ref ; ref = ref->next) {
const unsigned char *remote = ref->old_oid.hash;
struct object *o;
o = lookup_object(remote);
if (!o || !(o->flags & COMPLETE)) {
retval = 0;
if (!args->verbose)
continue;
fprintf(stderr,
"want %s (%s)\n", sha1_to_hex(remote),
ref->name);
continue;
}
if (!args->verbose)
continue;
fprintf(stderr,
"already have %s (%s)\n", sha1_to_hex(remote),
ref->name);
}
return retval;
}
static int sideband_demux(int in, int out, void *data)
{
int *xd = data;
int ret;
sigchain_push(SIGPIPE, SIG_IGN);
ret = recv_sideband("fetch-pack", xd[0], out);
close(out);
sigchain_pop(SIGPIPE);
return ret;
}
static int get_pack(struct fetch_pack_args *args,
int xd[2], char **pack_lockfile)
{
struct async demux;
int do_keep = args->keep_pack;
const char *cmd_name;
struct pack_header header;
int pass_header = 0;
struct child_process cmd = CHILD_PROCESS_INIT;
clone: open a shortcut for connectivity check In order to make sure the cloned repository is good, we run "rev-list --objects --not --all $new_refs" on the repository. This is expensive on large repositories. This patch attempts to mitigate the impact in this special case. In the "good" clone case, we only have one pack. If all of the following are met, we can be sure that all objects reachable from the new refs exist, which is the intention of running "rev-list ...": - all refs point to an object in the pack - there are no dangling pointers in any object in the pack - no objects in the pack point to objects outside the pack The second and third checks can be done with the help of index-pack as a slight variation of --strict check (which introduces a new condition for the shortcut: pack transfer must be used and the number of objects large enough to call index-pack). The first is checked in check_everything_connected after we get an "ok" from index-pack. "index-pack + new checks" is still faster than the current "index-pack + rev-list", which is the whole point of this patch. If any of the conditions fail, we fall back to the good old but expensive "rev-list ..". In that case it's even more expensive because we have to pay for the new checks in index-pack. But that should only happen when the other side is either buggy or malicious. Cloning linux-2.6 over file:// before after real 3m25.693s 2m53.050s user 5m2.037s 4m42.396s sys 0m13.750s 0m16.574s A more realistic test with ssh:// over wireless before after real 11m26.629s 10m4.213s user 5m43.196s 5m19.444s sys 0m35.812s 0m37.630s This shortcut is not applied to shallow clones, partly because shallow clones should have no more objects than a usual fetch and the cost of rev-list is acceptable, partly to avoid dealing with corner cases when grafting is involved. This shortcut does not apply to unpack-objects code path either because the number of objects must be small in order to trigger that code path. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-26 05:16:17 +04:00
int ret;
memset(&demux, 0, sizeof(demux));
if (use_sideband) {
/* xd[] is talking with upload-pack; subprocess reads from
* xd[0], spits out band#2 to stderr, and feeds us band#1
* through demux->out.
*/
demux.proc = sideband_demux;
demux.data = xd;
demux.out = -1;
if (start_async(&demux))
die("fetch-pack: unable to fork off sideband"
" demultiplexer");
}
else
demux.out = xd[0];
if (!args->keep_pack && unpack_limit) {
if (read_pack_header(demux.out, &header))
die("protocol error: bad pack header");
pass_header = 1;
if (ntohl(header.hdr_entries) < unpack_limit)
do_keep = 0;
else
do_keep = 1;
}
if (alternate_shallow_file) {
argv_array_push(&cmd.args, "--shallow-file");
argv_array_push(&cmd.args, alternate_shallow_file);
}
if (do_keep) {
if (pack_lockfile)
cmd.out = -1;
cmd_name = "index-pack";
argv_array_push(&cmd.args, cmd_name);
argv_array_push(&cmd.args, "--stdin");
if (!args->quiet && !args->no_progress)
argv_array_push(&cmd.args, "-v");
if (args->use_thin_pack)
argv_array_push(&cmd.args, "--fix-thin");
if (args->lock_pack || unpack_limit) {
char hostname[256];
if (gethostname(hostname, sizeof(hostname)))
xsnprintf(hostname, sizeof(hostname), "localhost");
argv_array_pushf(&cmd.args,
"--keep=fetch-pack %"PRIuMAX " on %s",
(uintmax_t)getpid(), hostname);
}
clone: open a shortcut for connectivity check In order to make sure the cloned repository is good, we run "rev-list --objects --not --all $new_refs" on the repository. This is expensive on large repositories. This patch attempts to mitigate the impact in this special case. In the "good" clone case, we only have one pack. If all of the following are met, we can be sure that all objects reachable from the new refs exist, which is the intention of running "rev-list ...": - all refs point to an object in the pack - there are no dangling pointers in any object in the pack - no objects in the pack point to objects outside the pack The second and third checks can be done with the help of index-pack as a slight variation of --strict check (which introduces a new condition for the shortcut: pack transfer must be used and the number of objects large enough to call index-pack). The first is checked in check_everything_connected after we get an "ok" from index-pack. "index-pack + new checks" is still faster than the current "index-pack + rev-list", which is the whole point of this patch. If any of the conditions fail, we fall back to the good old but expensive "rev-list ..". In that case it's even more expensive because we have to pay for the new checks in index-pack. But that should only happen when the other side is either buggy or malicious. Cloning linux-2.6 over file:// before after real 3m25.693s 2m53.050s user 5m2.037s 4m42.396s sys 0m13.750s 0m16.574s A more realistic test with ssh:// over wireless before after real 11m26.629s 10m4.213s user 5m43.196s 5m19.444s sys 0m35.812s 0m37.630s This shortcut is not applied to shallow clones, partly because shallow clones should have no more objects than a usual fetch and the cost of rev-list is acceptable, partly to avoid dealing with corner cases when grafting is involved. This shortcut does not apply to unpack-objects code path either because the number of objects must be small in order to trigger that code path. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-26 05:16:17 +04:00
if (args->check_self_contained_and_connected)
argv_array_push(&cmd.args, "--check-self-contained-and-connected");
}
else {
cmd_name = "unpack-objects";
argv_array_push(&cmd.args, cmd_name);
if (args->quiet || args->no_progress)
argv_array_push(&cmd.args, "-q");
clone: open a shortcut for connectivity check In order to make sure the cloned repository is good, we run "rev-list --objects --not --all $new_refs" on the repository. This is expensive on large repositories. This patch attempts to mitigate the impact in this special case. In the "good" clone case, we only have one pack. If all of the following are met, we can be sure that all objects reachable from the new refs exist, which is the intention of running "rev-list ...": - all refs point to an object in the pack - there are no dangling pointers in any object in the pack - no objects in the pack point to objects outside the pack The second and third checks can be done with the help of index-pack as a slight variation of --strict check (which introduces a new condition for the shortcut: pack transfer must be used and the number of objects large enough to call index-pack). The first is checked in check_everything_connected after we get an "ok" from index-pack. "index-pack + new checks" is still faster than the current "index-pack + rev-list", which is the whole point of this patch. If any of the conditions fail, we fall back to the good old but expensive "rev-list ..". In that case it's even more expensive because we have to pay for the new checks in index-pack. But that should only happen when the other side is either buggy or malicious. Cloning linux-2.6 over file:// before after real 3m25.693s 2m53.050s user 5m2.037s 4m42.396s sys 0m13.750s 0m16.574s A more realistic test with ssh:// over wireless before after real 11m26.629s 10m4.213s user 5m43.196s 5m19.444s sys 0m35.812s 0m37.630s This shortcut is not applied to shallow clones, partly because shallow clones should have no more objects than a usual fetch and the cost of rev-list is acceptable, partly to avoid dealing with corner cases when grafting is involved. This shortcut does not apply to unpack-objects code path either because the number of objects must be small in order to trigger that code path. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-26 05:16:17 +04:00
args->check_self_contained_and_connected = 0;
}
if (pass_header)
argv_array_pushf(&cmd.args, "--pack_header=%"PRIu32",%"PRIu32,
ntohl(header.hdr_version),
ntohl(header.hdr_entries));
if (fetch_fsck_objects >= 0
? fetch_fsck_objects
: transfer_fsck_objects >= 0
? transfer_fsck_objects
: 0)
argv_array_push(&cmd.args, "--strict");
cmd.in = demux.out;
cmd.git_cmd = 1;
if (start_command(&cmd))
die("fetch-pack: unable to fork off %s", cmd_name);
if (do_keep && pack_lockfile) {
*pack_lockfile = index_pack_lockfile(cmd.out);
close(cmd.out);
}
if (!use_sideband)
/* Closed by start_command() */
xd[0] = -1;
clone: open a shortcut for connectivity check In order to make sure the cloned repository is good, we run "rev-list --objects --not --all $new_refs" on the repository. This is expensive on large repositories. This patch attempts to mitigate the impact in this special case. In the "good" clone case, we only have one pack. If all of the following are met, we can be sure that all objects reachable from the new refs exist, which is the intention of running "rev-list ...": - all refs point to an object in the pack - there are no dangling pointers in any object in the pack - no objects in the pack point to objects outside the pack The second and third checks can be done with the help of index-pack as a slight variation of --strict check (which introduces a new condition for the shortcut: pack transfer must be used and the number of objects large enough to call index-pack). The first is checked in check_everything_connected after we get an "ok" from index-pack. "index-pack + new checks" is still faster than the current "index-pack + rev-list", which is the whole point of this patch. If any of the conditions fail, we fall back to the good old but expensive "rev-list ..". In that case it's even more expensive because we have to pay for the new checks in index-pack. But that should only happen when the other side is either buggy or malicious. Cloning linux-2.6 over file:// before after real 3m25.693s 2m53.050s user 5m2.037s 4m42.396s sys 0m13.750s 0m16.574s A more realistic test with ssh:// over wireless before after real 11m26.629s 10m4.213s user 5m43.196s 5m19.444s sys 0m35.812s 0m37.630s This shortcut is not applied to shallow clones, partly because shallow clones should have no more objects than a usual fetch and the cost of rev-list is acceptable, partly to avoid dealing with corner cases when grafting is involved. This shortcut does not apply to unpack-objects code path either because the number of objects must be small in order to trigger that code path. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-26 05:16:17 +04:00
ret = finish_command(&cmd);
if (!ret || (args->check_self_contained_and_connected && ret == 1))
args->self_contained_and_connected =
args->check_self_contained_and_connected &&
ret == 0;
else
die("%s failed", cmd_name);
if (use_sideband && finish_async(&demux))
die("error in sideband demultiplexer");
return 0;
}
static int cmp_ref_by_name(const void *a_, const void *b_)
{
const struct ref *a = *((const struct ref **)a_);
const struct ref *b = *((const struct ref **)b_);
return strcmp(a->name, b->name);
}
static struct ref *do_fetch_pack(struct fetch_pack_args *args,
int fd[2],
const struct ref *orig_ref,
struct ref **sought, int nr_sought,
struct shallow_info *si,
char **pack_lockfile)
{
struct ref *ref = copy_ref_list(orig_ref);
unsigned char sha1[20];
const char *agent_feature;
int agent_len;
sort_ref_list(&ref, ref_compare_name);
qsort(sought, nr_sought, sizeof(*sought), cmp_ref_by_name);
if ((args->depth > 0 || is_repository_shallow()) && !server_supports("shallow"))
die("Server does not support shallow clients");
if (server_supports("multi_ack_detailed")) {
if (args->verbose)
fprintf(stderr, "Server supports multi_ack_detailed\n");
multi_ack = 2;
if (server_supports("no-done")) {
if (args->verbose)
fprintf(stderr, "Server supports no-done\n");
if (args->stateless_rpc)
no_done = 1;
}
}
else if (server_supports("multi_ack")) {
if (args->verbose)
fprintf(stderr, "Server supports multi_ack\n");
multi_ack = 1;
}
if (server_supports("side-band-64k")) {
if (args->verbose)
fprintf(stderr, "Server supports side-band-64k\n");
use_sideband = 2;
}
else if (server_supports("side-band")) {
if (args->verbose)
fprintf(stderr, "Server supports side-band\n");
use_sideband = 1;
}
if (server_supports("allow-tip-sha1-in-want")) {
if (args->verbose)
fprintf(stderr, "Server supports allow-tip-sha1-in-want\n");
allow_unadvertised_object_request |= ALLOW_TIP_SHA1;
}
if (server_supports("allow-reachable-sha1-in-want")) {
if (args->verbose)
fprintf(stderr, "Server supports allow-reachable-sha1-in-want\n");
allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
}
if (!server_supports("thin-pack"))
args->use_thin_pack = 0;
if (!server_supports("no-progress"))
args->no_progress = 0;
if (!server_supports("include-tag"))
args->include_tag = 0;
if (server_supports("ofs-delta")) {
if (args->verbose)
fprintf(stderr, "Server supports ofs-delta\n");
} else
prefer_ofs_delta = 0;
if ((agent_feature = server_feature_value("agent", &agent_len))) {
agent_supported = 1;
if (args->verbose && agent_len)
fprintf(stderr, "Server version is %.*s\n",
agent_len, agent_feature);
}
if (everything_local(args, &ref, sought, nr_sought)) {
packet_flush(fd[1]);
goto all_done;
}
if (find_common(args, fd, sha1, ref) < 0)
if (!args->keep_pack)
/* When cloning, it is not unusual to have
* no common commit.
*/
warning("no common commits");
if (args->stateless_rpc)
packet_flush(fd[1]);
if (args->depth > 0)
setup_alternate_shallow(&shallow_lock, &alternate_shallow_file,
NULL);
else if (si->nr_ours || si->nr_theirs)
alternate_shallow_file = setup_temporary_shallow(si->shallow);
else
alternate_shallow_file = NULL;
if (get_pack(args, fd, pack_lockfile))
die("git fetch-pack: fetch failed.");
all_done:
return ref;
}
static void fetch_pack_config(void)
{
git_config_get_int("fetch.unpacklimit", &fetch_unpack_limit);
git_config_get_int("transfer.unpacklimit", &transfer_unpack_limit);
git_config_get_bool("repack.usedeltabaseoffset", &prefer_ofs_delta);
git_config_get_bool("fetch.fsckobjects", &fetch_fsck_objects);
git_config_get_bool("transfer.fsckobjects", &transfer_fsck_objects);
git_config(git_default_config, NULL);
}
static void fetch_pack_setup(void)
{
static int did_setup;
if (did_setup)
return;
fetch_pack_config();
if (0 <= transfer_unpack_limit)
unpack_limit = transfer_unpack_limit;
else if (0 <= fetch_unpack_limit)
unpack_limit = fetch_unpack_limit;
did_setup = 1;
}
static int remove_duplicates_in_refs(struct ref **ref, int nr)
{
struct string_list names = STRING_LIST_INIT_NODUP;
int src, dst;
for (src = dst = 0; src < nr; src++) {
struct string_list_item *item;
item = string_list_insert(&names, ref[src]->name);
if (item->util)
continue; /* already have it */
item->util = ref[src];
if (src != dst)
ref[dst] = ref[src];
dst++;
}
for (src = dst; src < nr; src++)
ref[src] = NULL;
string_list_clear(&names, 0);
return dst;
}
static void update_shallow(struct fetch_pack_args *args,
struct ref **sought, int nr_sought,
struct shallow_info *si)
{
struct sha1_array ref = SHA1_ARRAY_INIT;
int *status;
int i;
if (args->depth > 0 && alternate_shallow_file) {
if (*alternate_shallow_file == '\0') { /* --unshallow */
memoize common git-path "constant" files One of the most common uses of git_path() is to pass a constant, like git_path("MERGE_MSG"). This has two drawbacks: 1. The return value is a static buffer, and the lifetime is dependent on other calls to git_path, etc. 2. There's no compile-time checking of the pathname. This is OK for a one-off (after all, we have to spell it correctly at least once), but many of these constant strings appear throughout the code. This patch introduces a series of functions to "memoize" these strings, which are essentially globals for the lifetime of the program. We compute the value once, take ownership of the buffer, and return the cached value for subsequent calls. cache.h provides a helper macro for defining these functions as one-liners, and defines a few common ones for global use. Using a macro is a little bit gross, but it does nicely document the purpose of the functions. If we need to touch them all later (e.g., because we learned how to change the git_dir variable at runtime, and need to invalidate all of the stored values), it will be much easier to have the complete list. Note that the shared-global functions have separate, manual declarations. We could do something clever with the macros (e.g., expand it to a declaration in some places, and a declaration _and_ a definition in path.c). But there aren't that many, and it's probably better to stay away from too-magical macros. Likewise, if we abandon the C preprocessor in favor of generating these with a script, we could get much fancier. E.g., normalizing "FOO/BAR-BAZ" into "git_path_foo_bar_baz". But the small amount of saved typing is probably not worth the resulting confusion to readers who want to grep for the function's definition. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-08-10 12:38:57 +03:00
unlink_or_warn(git_path_shallow());
rollback_lock_file(&shallow_lock);
} else
commit_lock_file(&shallow_lock);
return;
}
if (!si->shallow || !si->shallow->nr)
return;
if (args->cloning) {
/*
* remote is shallow, but this is a clone, there are
* no objects in repo to worry about. Accept any
* shallow points that exist in the pack (iow in repo
* after get_pack() and reprepare_packed_git())
*/
struct sha1_array extra = SHA1_ARRAY_INIT;
unsigned char (*sha1)[20] = si->shallow->sha1;
for (i = 0; i < si->shallow->nr; i++)
if (has_sha1_file(sha1[i]))
sha1_array_append(&extra, sha1[i]);
if (extra.nr) {
setup_alternate_shallow(&shallow_lock,
&alternate_shallow_file,
&extra);
commit_lock_file(&shallow_lock);
}
sha1_array_clear(&extra);
return;
}
if (!si->nr_ours && !si->nr_theirs)
return;
remove_nonexistent_theirs_shallow(si);
if (!si->nr_ours && !si->nr_theirs)
return;
for (i = 0; i < nr_sought; i++)
sha1_array_append(&ref, sought[i]->old_oid.hash);
si->ref = &ref;
if (args->update_shallow) {
/*
* remote is also shallow, .git/shallow may be updated
* so all refs can be accepted. Make sure we only add
* shallow roots that are actually reachable from new
* refs.
*/
struct sha1_array extra = SHA1_ARRAY_INIT;
unsigned char (*sha1)[20] = si->shallow->sha1;
assign_shallow_commits_to_refs(si, NULL, NULL);
if (!si->nr_ours && !si->nr_theirs) {
sha1_array_clear(&ref);
return;
}
for (i = 0; i < si->nr_ours; i++)
sha1_array_append(&extra, sha1[si->ours[i]]);
for (i = 0; i < si->nr_theirs; i++)
sha1_array_append(&extra, sha1[si->theirs[i]]);
setup_alternate_shallow(&shallow_lock,
&alternate_shallow_file,
&extra);
commit_lock_file(&shallow_lock);
sha1_array_clear(&extra);
sha1_array_clear(&ref);
return;
}
/*
* remote is also shallow, check what ref is safe to update
* without updating .git/shallow
*/
status = xcalloc(nr_sought, sizeof(*status));
assign_shallow_commits_to_refs(si, NULL, status);
if (si->nr_ours || si->nr_theirs) {
for (i = 0; i < nr_sought; i++)
if (status[i])
sought[i]->status = REF_STATUS_REJECT_SHALLOW;
}
free(status);
sha1_array_clear(&ref);
}
struct ref *fetch_pack(struct fetch_pack_args *args,
int fd[], struct child_process *conn,
const struct ref *ref,
const char *dest,
struct ref **sought, int nr_sought,
struct sha1_array *shallow,
char **pack_lockfile)
{
struct ref *ref_cpy;
struct shallow_info si;
fetch_pack_setup();
if (nr_sought)
nr_sought = remove_duplicates_in_refs(sought, nr_sought);
if (!ref) {
packet_flush(fd[1]);
die("no matching remote head");
}
prepare_shallow_info(&si, shallow);
ref_cpy = do_fetch_pack(args, fd, ref, sought, nr_sought,
&si, pack_lockfile);
reprepare_packed_git();
update_shallow(args, sought, nr_sought, &si);
clear_shallow_info(&si);
return ref_cpy;
}