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2013-09-20Merge branch 'nd/fetch-into-shallow'Libravatar Junio C Hamano1-96/+32
When there is no sufficient overlap between old and new history during a fetch into a shallow repository, we unnecessarily sent objects the sending side knows the receiving end has. * nd/fetch-into-shallow: Add testcase for needless objects during a shallow fetch list-objects: mark more commits as edges in mark_edges_uninteresting list-objects: reduce one argument in mark_edges_uninteresting upload-pack: delegate rev walking in shallow fetch to pack-objects shallow: add setup_temporary_shallow() shallow: only add shallow graft points to new shallow file move setup_alternate_shallow and write_shallow_commits to shallow.c
2013-08-28upload-pack: delegate rev walking in shallow fetch to pack-objectsLibravatar Nguyễn Thái Ngọc Duy1-96/+32
upload-pack has a special revision walking code for shallow recipients. It works almost like the similar code in pack-objects except: 1. in upload-pack, graft points could be added for deepening; 2. also when the repository is deepened, the shallow point will be moved further away from the tip, but the old shallow point will be marked as edge to produce more efficient packs. See 6523078 (make shallow repository deepening more network efficient - 2009-09-03). Pass the file to pack-objects via --shallow-file. This will override $GIT_DIR/shallow and give pack-objects the exact repository shape that upload-pack has. mark edge commits by revision command arguments. Even if old shallow points are passed as "--not" revisions as in this patch, they will not be picked up by mark_edges_uninteresting() because this function looks up to parents for edges, while in this case the edge is the children, in the opposite direction. This will be fixed in an later patch when all given uninteresting commits are marked as edges. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-08cache.h: move remote/connect API out of itLibravatar Junio C Hamano1-0/+1
The definition of "struct ref" in "cache.h", a header file so central to the system, always confused me. This structure is not about the local ref used by sha1-name API to name local objects. It is what refspecs are expanded into, after finding out what refs the other side has, to define what refs are updated after object transfer succeeds to what values. It belongs to "remote.h" together with "struct refspec". While we are at it, also move the types and functions related to the Git transport connection to a new header file connect.h Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-04-28upload-pack: ignore 'shallow' lines with unknown obj-idsLibravatar Michael Heemskerk1-1/+1
When the client sends a 'shallow' line for an object that the server does not have, the server currently dies with the error: "did not find object for shallow <obj-id>". The client may have truncated the history at the commit by fetching shallowly from a different server, or the commit may have been garbage collected by the server. In either case, this unknown commit is not relevant for calculating the pack that is to be sent and can be safely ignored, and it is not used when recomputing where the updated history of the client is cauterised. The documentation in technical/pack-protocol.txt has been updated to remove the restriction that "Clients MUST NOT mention an obj-id which it does not know exists on the server". This requirement is not realistic because clients cannot know whether an object has been garbage collected by the server. Signed-off-by: Michael Heemskerk <mheemskerk@atlassian.com> Reviewed-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-04-01Merge branch 'jk/pkt-line-cleanup'Libravatar Junio C Hamano1-28/+12
Clean up pkt-line API, implementation and its callers to make them more robust. * jk/pkt-line-cleanup: do not use GIT_TRACE_PACKET=3 in tests remote-curl: always parse incoming refs remote-curl: move ref-parsing code up in file remote-curl: pass buffer straight to get_remote_heads teach get_remote_heads to read from a memory buffer pkt-line: share buffer/descriptor reading implementation pkt-line: provide a LARGE_PACKET_MAX static buffer pkt-line: move LARGE_PACKET_MAX definition from sideband pkt-line: teach packet_read_line to chomp newlines pkt-line: provide a generic reading function with options pkt-line: drop safe_write function pkt-line: move a misplaced comment write_or_die: raise SIGPIPE when we get EPIPE upload-archive: use argv_array to store client arguments upload-archive: do not copy repo name send-pack: prefer prefixcmp over memcmp in receive_status fetch-pack: fix out-of-bounds buffer offset in get_ack upload-pack: remove packet debugging harness upload-pack: do not add duplicate objects to shallow list upload-pack: use get_sha1_hex to parse "shallow" lines
2013-03-25Merge branch 'jk/peel-ref'Libravatar Junio C Hamano1-4/+2
Recent optimization broke shallow clones. * jk/peel-ref: upload-pack: load non-tip "want" objects from disk upload-pack: make sure "want" objects are parsed upload-pack: drop lookup-before-parse optimization
2013-03-21Merge branch 'jc/fetch-raw-sha1'Libravatar Junio C Hamano1-6/+19
Allows requests to fetch objects at any tip of refs (including hidden ones). It seems that there may be use cases even outside Gerrit (e.g. $gmane/215701). * jc/fetch-raw-sha1: fetch: fetch objects by their exact SHA-1 object names upload-pack: optionally allow fetching from the tips of hidden refs fetch: use struct ref to represent refs to be fetched parse_fetch_refspec(): clarify the codeflow a bit
2013-03-16upload-pack: load non-tip "want" objects from diskLibravatar Jeff King1-2/+2
It is a long-time security feature that upload-pack will not serve any "want" lines that do not correspond to the tip of one of our refs. Traditionally, this was enforced by checking the objects in the in-memory hash; they should have been loaded and received the OUR_REF flag during the advertisement. The stateless-rpc mode, however, has a race condition here: one process advertises, and another receives the want lines, so the refs may have changed in the interim. To address this, commit 051e400 added a new verification mode; if the object is not OUR_REF, we set a "has_non_tip" flag, and then later verify that the requested objects are reachable from our current tips. However, we still die immediately when the object is not in our in-memory hash, and at this point we should only have loaded our tip objects. So the check_non_tip code path does not ever actually trigger, as any non-tip objects would have already caused us to die. We can fix that by using parse_object instead of lookup_object, which will load the object from disk if it has not already been loaded. We still need to check that parse_object does not return NULL, though, as it is possible we do not have the object at all. A more appropriate error message would be "no such object" rather than "not our ref"; however, we do not want to leak information about what objects are or are not in the object database, so we continue to use the same "not our ref" message that would be produced by an unreachable object. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-03-16upload-pack: make sure "want" objects are parsedLibravatar Jeff King1-1/+1
When upload-pack receives a "want" line from the client, it adds it to an object array. We call lookup_object to find the actual object, which will only check for objects already in memory. This works because we are expecting to find objects that we already loaded during the ref advertisement. We use the resulting object structs for a variety of purposes. Some of them care only about the object flags, but others care about the type of the object (e.g., ok_to_give_up), or even feed them to the revision parser (when --depth is used), which assumes that objects it receives are fully parsed. Once upon a time, this was OK; any object we loaded into memory would also have been parsed. But since 435c833 (upload-pack: use peel_ref for ref advertisements, 2012-10-04), we try to avoid parsing objects during the ref advertisement. This means that lookup_object may return an object with a type of OBJ_NONE. The resulting mess depends on the exact set of objects, but can include the revision parser barfing, or the shallow code sending the wrong set of objects. This patch teaches upload-pack to parse each "want" object as we receive it. We do not replace the lookup_object call with parse_object, as the current code is careful not to let just any object appear on a "want" line, but rather only one we have previously advertised (whereas parse_object would actually load any arbitrary object from disk). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-03-16upload-pack: drop lookup-before-parse optimizationLibravatar Jeff King1-3/+1
When we receive a "have" line from the client, we want to load the object pointed to by the sha1. However, we are careful to do: o = lookup_object(sha1); if (!o || !o->parsed) o = parse_object(sha1); to avoid loading the object from disk if we have already seen it. However, since ccdc603 (parse_object: try internal cache before reading object db), parse_object already does this optimization internally. We can just call parse_object directly. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-20pkt-line: provide a LARGE_PACKET_MAX static bufferLibravatar Jeff King1-7/+5
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>
2013-02-20pkt-line: teach packet_read_line to chomp newlinesLibravatar Jeff King1-8/+0
The packets sent during ref negotiation are all terminated by newline; even though the code to chomp these newlines is short, we end up doing it in a lot of places. This patch teaches packet_read_line to auto-chomp the trailing newline; this lets us get rid of a lot of inline chomping code. As a result, some call-sites which are not reading line-oriented data (e.g., when reading chunks of packfiles alongside sideband) transition away from packet_read_line to the generic packet_read interface. This patch converts all of the existing callsites. Since the function signature of packet_read_line does not change (but its behavior does), there is a possibility of new callsites being introduced in later commits, silently introducing an incompatibility. However, since a later patch in this series will change the signature, such a commit would have to be merged directly into this commit, not to the tip of the series; we can therefore ignore the issue. This is an internal cleanup and should produce no change of behavior in the normal case. However, there is one corner case to note. Callers of packet_read_line have never been able to tell the difference between a flush packet ("0000") and an empty packet ("0004"), as both cause packet_read_line to return a length of 0. Readers treat them identically, even though Documentation/technical/protocol-common.txt says we must not; it also says that implementations should not send an empty pkt-line. By stripping out the newline before the result gets to the caller, we will now treat the newline-only packet ("0005\n") the same as an empty packet, which in turn gets treated like a flush packet. In practice this doesn't matter, as neither empty nor newline-only packets are part of git's protocols (at least not for the line-oriented bits, and readers who are not expecting line-oriented packets will be calling packet_read directly, anyway). But even if we do decide to care about the distinction later, it is orthogonal to this patch. The right place to tighten would be to stop treating empty packets as flush packets, and this change does not make doing so any harder. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-20pkt-line: drop safe_write functionLibravatar Jeff King1-1/+2
This is just write_or_die by another name. The one distinction is that write_or_die will treat EPIPE specially by suppressing error messages. That's fine, as we die by SIGPIPE anyway (and in the off chance that it is disabled, write_or_die will simulate it). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-20upload-pack: remove packet debugging harnessLibravatar Jeff King1-9/+0
If you set the GIT_DEBUG_SEND_PACK environment variable, upload-pack will dump lines it receives in the receive_needs phase to a descriptor. This debugging harness is a strict subset of what GIT_TRACE_PACKET can do. Let's just drop it in favor of that. A few tests used GIT_DEBUG_SEND_PACK to confirm which objects get sent; we have to adapt them to the new output format. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-20upload-pack: do not add duplicate objects to shallow listLibravatar Jeff King1-2/+4
When the client tells us it has a shallow object via "shallow <sha1>", we make sure we have the object, mark it with a flag, then add it to a dynamic array of shallow objects. This means that a client can get us to allocate arbitrary amounts of memory just by flooding us with shallow lines (whether they have the objects or not). You can demonstrate it easily with: yes '0035shallow e83c5163316f89bfbde7d9ab23ca2e25604af290' | git-upload-pack git.git We already protect against duplicates in want lines by checking if our flag is already set; let's do the same thing here. Note that a client can still get us to allocate some amount of memory by marking every object in the repo as "shallow" (or "want"). But this at least bounds it with the number of objects in the repository, which is not under the control of an upload-pack client. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-20upload-pack: use get_sha1_hex to parse "shallow" linesLibravatar Jeff King1-1/+1
When we receive a line like "shallow <sha1>" from the client, we feed the <sha1> part to get_sha1. This is a mistake, as the argument on a shallow line is defined by Documentation/technical/pack-protocol.txt to contain an "obj-id". This is never defined in the BNF, but it is clear from the text and from the other uses that it is meant to be a hex sha1, not an arbitrary identifier (and that is what fetch-pack has always sent). We should be using get_sha1_hex instead, which doesn't allow the client to request arbitrary junk like "HEAD@{yesterday}". Because this is just marking shallow objects, the client couldn't actually do anything interesting (like fetching objects from unreachable reflog entries), but we should keep our parsing tight to be on the safe side. Because get_sha1 is for the most part a superset of get_sha1_hex, in theory the only behavior change should be disallowing non-hex object references. However, there is one interesting exception: get_sha1 will only parse a 40-character hex sha1 if the string has exactly 40 characters, whereas get_sha1_hex will just eat the first 40 characters, leaving the rest. That means that current versions of git-upload-pack will not accept a "shallow" packet that has a trailing newline, even though the protocol documentation is clear that newlines are allowed (even encouraged) in non-binary parts of the protocol. This never mattered in practice, though, because fetch-pack, contrary to the protocol documentation, does not include a newline in its shallow lines. JGit follows its lead (though it correctly is strict on the parsing end about wanting a hex object id). We do not adjust fetch-pack to send newlines here, as it would break communication with older versions of git (and there is no actual benefit to doing so, except for consistency with other parts of the protocol). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-17Merge branch 'jc/hidden-refs'Libravatar Junio C Hamano1-30/+33
Allow the server side to redact the refs/ namespace it shows to the client. Will merge to 'master'. * jc/hidden-refs: upload/receive-pack: allow hiding ref hierarchies upload-pack: simplify request validation upload-pack: share more code
2013-02-07upload-pack: optionally allow fetching from the tips of hidden refsLibravatar Junio C Hamano1-6/+19
With uploadpack.allowtipsha1inwant configuration option set, future versions of "git fetch" that allow an exact object name (likely to have been obtained out of band) on the LHS of the fetch refspec can make a request with a "want" line that names an object that may not have been advertised due to transfer.hiderefs configuration. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-07upload/receive-pack: allow hiding ref hierarchiesLibravatar Junio C Hamano1-1/+13
A repository may have refs that are only used for its internal bookkeeping purposes that should not be exposed to the others that come over the network. Teach upload-pack to omit some refs from its initial advertisement by paying attention to the uploadpack.hiderefs multi-valued configuration variable. Do the same to receive-pack via the receive.hiderefs variable. As a convenient short-hand, allow using transfer.hiderefs to set the value to both of these variables. Any ref that is under the hierarchies listed on the value of these variable is excluded from responses to requests made by "ls-remote", "fetch", etc. (for upload-pack) and "push" (for receive-pack). Because these hidden refs do not count as OUR_REF, an attempt to fetch objects at the tip of them will be rejected, and because these refs do not get advertised, "git push :" will not see local branches that have the same name as them as "matching" ones to be sent. An attempt to update/delete these hidden refs with an explicit refspec, e.g. "git push origin :refs/hidden/22", is rejected. This is not a new restriction. To the pusher, it would appear that there is no such ref, so its push request will conclude with "Now that I sent you all the data, it is time for you to update the refs. I saw that the ref did not exist when I started pushing, and I want the result to point at this commit". The receiving end will apply the compare-and-swap rule to this request and rejects the push with "Well, your update request conflicts with somebody else; I see there is such a ref.", which is the right thing to do. Otherwise a push to a hidden ref will always be "the last one wins", which is not a good default. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-01Merge branch 'nd/fetch-depth-is-broken'Libravatar Junio C Hamano1-3/+10
"git fetch --depth" was broken in at least three ways. The resulting history was deeper than specified by one commit, it was unclear how to wipe the shallowness of the repository with the command, and documentation was misleading. * nd/fetch-depth-is-broken: fetch: elaborate --depth action upload-pack: fix off-by-one depth calculation in shallow clone fetch: add --unshallow for turning shallow repo into complete one
2013-01-28upload-pack: simplify request validationLibravatar Junio C Hamano1-17/+11
Long time ago, we used to punt on a large (read: asking for more than 256 refs) fetch request and instead sent a full pack, because we couldn't fit many refs on the command line of rev-list we run internally to enumerate the objects to be sent. To fix this, 565ebbf (upload-pack: tighten request validation., 2005-10-24), added a check to count the number of refs in the request and matched with the number of refs we advertised, and changed the invocation of rev-list to pass "--all" to it, still keeping us under the command line argument limit. However, these days we feed the list of objects requested and the list of objects the other end is known to have via standard input, so there is no longer a valid reason to special case a full clone request. Remove the code associated with "create_full_pack" to simplify the logic. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-01-18upload-pack: share more codeLibravatar Junio C Hamano1-17/+14
We mark the objects pointed at our refs with "OUR_REF" flag in two functions (mark_our_ref() and send_ref()), but we can just use the former as a helper for the latter. Update the way mark_our_ref() prepares in-core object to use lookup_unknown_object() to delay reading the actual object data, just like we did in 435c833 (upload-pack: use peel_ref for ref advertisements, 2012-10-04). Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-01-14Merge branch 'nd/upload-pack-shallow-must-be-commit'Libravatar Junio C Hamano1-0/+2
A minor consistency check patch that does not have much relevance to the real world. * nd/upload-pack-shallow-must-be-commit: upload-pack: only accept commits from "shallow" line
2013-01-11fetch: add --unshallow for turning shallow repo into complete oneLibravatar Nguyễn Thái Ngọc Duy1-3/+10
The user can do --depth=2147483647 (*) for restoring complete repo now. But it's hard to remember. Any other numbers larger than the longest commit chain in the repository would also do, but some guessing may be involved. Make easy-to-remember --unshallow an alias for --depth=2147483647. Make upload-pack recognize this special number as infinite depth. The effect is essentially the same as before, except that upload-pack is more efficient because it does not have to traverse to the bottom anymore. The chance of a user actually wanting exactly 2147483647 commits depth, not infinite, on a repository with a history that long, is probably too small to consider. The client can learn to add or subtract one commit to avoid the special treatment when that actually happens. (*) This is the largest positive number a 32-bit signed integer can contain. JGit and older C Git store depth as "int" so both are OK with this number. Dulwich does not support shallow clone. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-01-08upload-pack: only accept commits from "shallow" lineLibravatar Nguyễn Thái Ngọc Duy1-0/+2
We only allow cuts at commits, not arbitrary objects. upload-pack will fail eventually in register_shallow if a non-commit is given with a generic error "Object %s is a %s, not a commit". Check it early and give a more accurate error. This should never show up in an ordinary session. It's for buggy clients, or when the user manually edits .git/shallow. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-10-04upload-pack: use peel_ref for ref advertisementsLibravatar Jeff King1-11/+3
When upload-pack advertises refs, we attempt to peel tags and advertise the peeled version. We currently hand-roll the tag dereferencing, and use as many optimizations as we can to avoid loading non-tag objects into memory. Not only has peel_ref recently learned these optimizations, too, but it also contains an even more important one: it has access to the "peeled" data from the pack-refs file. That means we can avoid not only loading annotated tags entirely, but also avoid doing any kind of object lookup at all. This cut the CPU time to advertise refs by 50% in the linux-2.6 repo, as measured by: echo 0000 | git-upload-pack . >/dev/null best-of-five, warm cache, objects and refs fully packed: [before] [after] real 0m0.026s real 0m0.013s user 0m0.024s user 0m0.008s sys 0m0.000s sys 0m0.000s Those numbers are irrelevantly small compared to an actual fetch. Here's a larger repo (400K refs, of which 12K are unique, and of which only 107 are unique annotated tags): [before] [after] real 0m0.704s real 0m0.596s user 0m0.600s user 0m0.496s sys 0m0.096s sys 0m0.092s This shows only a 15% speedup (mostly because it has fewer actual tags to parse), but a larger absolute value (100ms, which isn't a lot compared to a real fetch, but this advertisement happens on every fetch, even if the client is just finding out they are completely up to date). In truly pathological cases, where you have a large number of unique annotated tags, it can make an even bigger difference. Here are the numbers for a linux-2.6 repository that has had every seventh commit tagged (so about 50K tags): [before] [after] real 0m0.443s real 0m0.097s user 0m0.416s user 0m0.080s sys 0m0.024s sys 0m0.012s Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-08-03include agent identifier in capability stringLibravatar Jeff King1-2/+5
Instead of having the client advertise a particular version number in the git protocol, we have managed extensions and backwards compatibility by having clients and servers advertise capabilities that they support. This is far more robust than having each side consult a table of known versions, and provides sufficient information for the protocol interaction to complete. However, it does not allow servers to keep statistics on which client versions are being used. This information is not necessary to complete the network request (the capabilities provide enough information for that), but it may be helpful to conduct a general survey of client versions in use. We already send the client version in the user-agent header for http requests; adding it here allows us to gather similar statistics for non-http requests. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-01-29Merge branch 'jk/parse-object-cached'Libravatar Junio C Hamano1-4/+7
* jk/parse-object-cached: upload-pack: avoid parsing tag destinations upload-pack: avoid parsing objects during ref advertisement parse_object: try internal cache before reading object db
2012-01-08server_supports(): parse feature list more carefullyLibravatar Junio C Hamano1-9/+13
We have been carefully choosing feature names used in the protocol extensions so that the vocabulary does not contain a word that is a substring of another word, so it is not a real problem, but we have recently added "quiet" feature word, which would mean we cannot later add some other word with "quiet" (e.g. "quiet-push"), which is awkward. Let's make sure that we can eventually be able to do so by teaching the clients and servers that feature words consist of non whitespace letters. This parser also allows us to later add features with parameters e.g. "feature=1.5" (parameter values need to be quoted for whitespaces, but we will worry about the detauls when we do introduce them). Signed-off-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Clemens Buchacher <drizzd@aon.at> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-01-06upload-pack: avoid parsing tag destinationsLibravatar Jeff King1-2/+1
When upload-pack advertises refs, it dereferences any tags it sees, and shows the resulting sha1 to the client. It does this by calling deref_tag. That function must load and parse each tag object to find the sha1 of the tagged object. However, it also ends up parsing the tagged object itself, which is not strictly necessary for upload-pack's use. Each tag produces two object loads (assuming it is not a recursive tag), when it could get away with only a single one. Dropping the second load halves the effort we spend. The downside is that we are no longer verifying the resulting object by loading it. In particular: 1. We never cross-check the "type" field given in the tag object with the type of the pointed-to object. If the tag says it points to a tag but doesn't, then we will keep peeling and realize the error. If the tag says it points to a non-tag but actually points to a tag, we will stop peeling and just advertise the pointed-to tag. 2. If we are missing the pointed-to object, we will not realize (because we never even look it up in the object db). However, both of these are errors in the object database, and both will be detected if a client actually requests the broken objects in question. So we are simply pushing the verification away from the advertising stage, and down to the actual fetching stage. On my test repo with 120K refs, this drops the time to advertise the refs from ~3.2s to ~2.0s. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-01-06upload-pack: avoid parsing objects during ref advertisementLibravatar Jeff King1-3/+7
When we advertise a ref, the first thing we do is parse the pointed-to object. This gives us two things: 1. a "struct object" we can use to store flags 2. the type of the object, so we know whether we need to dereference it as a tag Instead, we can just use lookup_unknown_object to get an object struct, and then fill in just the type field using sha1_object_info (which, in the case of packed files, can find the information without actually inflating the object data). This can save time if you have a large number of refs, and the client isn't actually going to request those refs (e.g., because most of them are already up-to-date). The downside is that we are no longer verifying objects that we advertise by fully parsing them (however, we do still know we actually have them, because sha1_object_info must find them to get the type). While we might fail to detect a corrupt object here, if the client actually fetches the object, we will parse (and verify) it then. On a repository with 120K refs, the advertisement portion of upload-pack goes from ~3.4s to 3.2s (the failure to speed up more is largely due to the fact that most of these refs are tags, which need dereferenced to find the tag destination anyway). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-12-05i18n: add infrastructure for translating Git with gettextLibravatar Ævar Arnfjörð Bjarmason1-0/+2
Change the skeleton implementation of i18n in Git to one that can show localized strings to users for our C, Shell and Perl programs using either GNU libintl or the Solaris gettext implementation. This new internationalization support is enabled by default. If gettext isn't available, or if Git is compiled with NO_GETTEXT=YesPlease, Git falls back on its current behavior of showing interface messages in English. When using the autoconf script we'll auto-detect if the gettext libraries are installed and act appropriately. This change is somewhat large because as well as adding a C, Shell and Perl i18n interface we're adding a lot of tests for them, and for those tests to work we need a skeleton PO file to actually test translations. A minimal Icelandic translation is included for this purpose. Icelandic includes multi-byte characters which makes it easy to test various edge cases, and it's a language I happen to understand. The rest of the commit message goes into detail about various sub-parts of this commit. = Installation Gettext .mo files will be installed and looked for in the standard $(prefix)/share/locale path. GIT_TEXTDOMAINDIR can also be set to override that, but that's only intended to be used to test Git itself. = Perl Perl code that's to be localized should use the new Git::I18n module. It imports a __ function into the caller's package by default. Instead of using the high level Locale::TextDomain interface I've opted to use the low-level (equivalent to the C interface) Locale::Messages module, which Locale::TextDomain itself uses. Locale::TextDomain does a lot of redundant work we don't need, and some of it would potentially introduce bugs. It tries to set the $TEXTDOMAIN based on package of the caller, and has its own hardcoded paths where it'll search for messages. I found it easier just to completely avoid it rather than try to circumvent its behavior. In any case, this is an issue wholly internal Git::I18N. Its guts can be changed later if that's deemed necessary. See <AANLkTilYD_NyIZMyj9dHtVk-ylVBfvyxpCC7982LWnVd@mail.gmail.com> for a further elaboration on this topic. = Shell Shell code that's to be localized should use the git-sh-i18n library. It's basically just a wrapper for the system's gettext.sh. If gettext.sh isn't available we'll fall back on gettext(1) if it's available. The latter is available without the former on Solaris, which has its own non-GNU gettext implementation. We also need to emulate eval_gettext() there. If neither are present we'll use a dumb printf(1) fall-through wrapper. = About libcharset.h and langinfo.h We use libcharset to query the character set of the current locale if it's available. I.e. we'll use it instead of nl_langinfo if HAVE_LIBCHARSET_H is set. The GNU gettext manual recommends using langinfo.h's nl_langinfo(CODESET) to acquire the current character set, but on systems that have libcharset.h's locale_charset() using the latter is either saner, or the only option on those systems. GNU and Solaris have a nl_langinfo(CODESET), FreeBSD can use either, but MinGW and some others need to use libcharset.h's locale_charset() instead. =Credits This patch is based on work by Jeff Epler <jepler@unpythonic.net> who did the initial Makefile / C work, and a lot of comments from the Git mailing list, including Jonathan Nieder, Jakub Narebski, Johannes Sixt, Erik Faye-Lund, Peter Krefting, Junio C Hamano, Thomas Rast and others. [jc: squashed a small Makefile fix from Ramsay] Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-10-05Merge branch 'jc/fetch-verify'Libravatar Junio C Hamano1-1/+3
* jc/fetch-verify: fetch: verify we have everything we need before updating our ref rev-list --verify-object list-objects: pass callback data to show_objects()
2011-10-05Merge branch 'jc/traverse-commit-list'Libravatar Junio C Hamano1-14/+1
* jc/traverse-commit-list: revision.c: update show_object_with_name() without using malloc() revision.c: add show_object_with_name() helper function rev-list: fix finish_object() call
2011-09-01list-objects: pass callback data to show_objects()Libravatar Junio C Hamano1-1/+3
The traverse_commit_list() API takes two callback functions, one to show commit objects, and the other to show other kinds of objects. Even though the former has a callback data parameter, so that the callback does not have to rely on global state, the latter does not. Give the show_objects() callback the same callback data parameter. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-24Sync with 1.7.6.1Libravatar Junio C Hamano1-0/+2
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-24get_indexed_object can return NULL if nothing is in that slot; check for itLibravatar Brian Harring1-0/+2
This fixes a segfault introduced by 051e400; via it, no longer able to trigger the http/smartserv race. Signed-off-by: Brian Harring <ferringb@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-22revision.c: add show_object_with_name() helper functionLibravatar Junio C Hamano1-14/+1
There are two copies of traverse_commit_list callback that show the object name followed by pathname the object was found, to produce output similar to "rev-list --objects". Unify them. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-08-17Merge branch 'jc/maint-smart-http-race-upload-pack'Libravatar Junio C Hamano1-9/+98
* jc/maint-smart-http-race-upload-pack: helping smart-http/stateless-rpc fetch race
2011-08-08helping smart-http/stateless-rpc fetch raceLibravatar Junio C Hamano1-9/+98
A request to fetch from a client over smart HTTP protocol is served in multiple steps. In the first round, the server side shows the set of refs it has and their values, and the client picks from them and sends "I want to fetch the history leading to these commits". When the server tries to respond to this second request, its refs may have progressed by a push from elsewhere. By design, we do not allow fetching objects that are not at the tip of an advertised ref, and the server rejects such a request. The client needs to try again, which is not ideal especially for a busy server. Teach upload-pack (which is the workhorse driven by git-daemon and smart http server interface) that it is OK for a smart-http client to ask for commits that are not at the tip of any advertised ref, as long as they are reachable from advertised refs. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-07-11ref namespaces: Support remote repositories via upload-pack and receive-packLibravatar Josh Triplett1-7/+8
Change upload-pack and receive-pack to use the namespace-prefixed refs when working with the repository, and use the unprefixed refs when talking to the client, maintaining the masquerade. This allows clone, pull, fetch, and push to work with a suitably configured GIT_NAMESPACE. receive-pack advertises refs outside the current namespace as .have refs (as it currently does for refs in alternates), so that the client can use them to minimize data transfer but will otherwise ignore them. With appropriate configuration, this also allows http-backend to expose namespaces as multiple repositories with different paths. This only requires setting GIT_NAMESPACE, which http-backend passes through to upload-pack and receive-pack. Signed-off-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Jamey Sharp <jamey@minilop.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-04-27Merge branch 'jk/maint-upload-pack-shallow'Libravatar Junio C Hamano1-12/+11
* jk/maint-upload-pack-shallow: upload-pack: start pack-objects before async rev-list
2011-04-06upload-pack: start pack-objects before async rev-listLibravatar Jeff King1-12/+11
In a pthread-enabled version of upload-pack, there's a race condition that can cause a deadlock on the fflush(NULL) we call from run-command. What happens is this: 1. Upload-pack is informed we are doing a shallow clone. 2. We call start_async() to spawn a thread that will generate rev-list results to feed to pack-objects. It gets a file descriptor to a pipe which will eventually hook to pack-objects. 3. The rev-list thread uses fdopen to create a new output stream around the fd we gave it, called pack_pipe. 4. The thread writes results to pack_pipe. Outside of our control, libc is doing locking on the stream. We keep writing until the OS pipe buffer is full, and then we block in write(), still holding the lock. 5. The main thread now uses start_command to spawn pack-objects. Before forking, it calls fflush(NULL) to flush every stdio output buffer. It blocks trying to get the lock on pack_pipe. And we have a deadlock. The thread will block until somebody starts reading from the pipe. But nobody will read from the pipe until we finish flushing to the pipe. To fix this, we swap the start order: we start the pack-objects reader first, and then the rev-list writer after. Thus the problematic fflush(NULL) happens before we even open the new file descriptor (and even if it didn't, flushing should no longer block, as the reader at the end of the pipe is now active). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-03-29Merge branches 'sp/maint-fetch-pack-stop-early' and ↵Libravatar Junio C Hamano1-3/+4
'sp/maint-upload-pack-stop-early' * sp/maint-fetch-pack-stop-early: enable "no-done" extension only when fetching over smart-http * sp/maint-upload-pack-stop-early: enable "no-done" extension only when serving over smart-http
2011-03-29Revert two "no-done" revertsLibravatar Junio C Hamano1-4/+16
Last night I had to make these two emergency reverts, but now we have a better understanding of which part of the topic was broken, let's get rid of the revert to fix it correctly. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-03-29enable "no-done" extension only when serving over smart-httpLibravatar Junio C Hamano1-3/+4
Do not advertise no-done capability when upload-pack is not serving over smart-http, as there is no way for this server to know when it should stop reading in-flight data from the client, even though it is necessary to drain all the in-flight data in order to unblock the client. Signed-off-by: Junio C Hamano <gitster@pobox.com> Acked-by: Shawn O. Pearce <spearce@spearce.org>
2011-03-28Revert "upload-pack: Implement no-done capability"Libravatar Junio C Hamano1-16/+4
This reverts 3e63b21 (upload-pack: Implement no-done capability, 2011-03-14). Together with 761ecf0 (fetch-pack: Implement no-done capability, 2011-03-14) it seems to make the fetch-pack process out of sync and makes it keep talking long after upload-pack stopped listening to it, terminating the process with SIGPIPE.
2011-03-22Merge branch 'sp/maint-upload-pack-stop-early'Libravatar Junio C Hamano1-3/+24
* sp/maint-upload-pack-stop-early: upload-pack: Implement no-done capability upload-pack: More aggressively send 'ACK %s ready'
2011-03-15upload-pack: Implement no-done capabilityLibravatar Shawn O. Pearce1-4/+16
If the client requests both multi_ack_detailed and no-done then upload-pack is free to immediately send a PACK following its first 'ACK %s ready' message. The upload-pack response actually winds up being: ACK %s common ... (maybe more) ... ACK %s ready NAK ACK %s PACK.... the pack stream .... For smart HTTP connections this saves one HTTP RPC, reducing the overall latency for a trivial fetch. For git:// and ssh:// a no-done option slightly reduces latency by removing one server->client->server round-trip at the end of the common ancestor negotiation. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-03-14upload-pack: More aggressively send 'ACK %s ready'Libravatar Shawn O. Pearce1-0/+9
If a client is merely following the remote (and has not made any new commits itself), all "have %s" lines sent by the client will be common to the server. As all lines are common upload-pack never calls ok_to_give_up() and does not compute if it has a good cut point in the commit graph. Without this computation the following client is going to send all tagged commits, as these were determined to be COMMON_REF during the initial advertisement, but the client does not parse their history to transitively pass the COMMON flag and empty its queue of commits. For git.git with 339 commit tags, it takes clients 11 rounds of negotation to fully send all tagged commits and exhaust its queue of things to send as common. This is pretty slow for a client that has not done any local development activity. Force computing ok_to_give_up() and send "ACK %s ready" at the end of the current round if this round only contained common objects and ok_to_give_up() was therefore not called. This may allow the client to break early, avoiding transmission of the COMMON_REFs. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>