Commit graph

53 commits

Author SHA1 Message Date
Jeff King
d0229abd93 object: convert lookup_object() to use object_id
There are no callers left of lookup_object() that aren't just passing us
the "hash" member of a "struct object_id". Let's take the whole struct,
which gets us closer to removing all raw sha1 variables.  It also
matches the existing conversions of lookup_blob(), etc.

The conversions of callers were done by hand, but they're all mechanical
one-liners.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-20 10:18:09 -07:00
Jeff King
fde67d6896 prune: use bitmaps for reachability traversal
Pruning generally has to traverse the whole commit graph in order to
see which objects are reachable. This is the exact problem that
reachability bitmaps were meant to solve, so let's use them (if they're
available, of course).

Here are timings on git.git:

  Test                            HEAD^             HEAD
  ------------------------------------------------------------------------
  5304.6: prune with bitmaps      3.65(3.56+0.09)   1.01(0.92+0.08) -72.3%

And on linux.git:

  Test                            HEAD^               HEAD
  --------------------------------------------------------------------------
  5304.6: prune with bitmaps      35.05(34.79+0.23)   3.00(2.78+0.21) -91.4%

The tests show a pretty optimal case, as we'll have just repacked and
should have pretty good coverage of all refs with our bitmaps. But
that's actually pretty realistic: normally prune is run via "gc" right
after repacking.

A few notes on the implementation:

  - the change is actually in reachable.c, so it would improve
    reachability traversals by "reflog expire --stale-fix", as well.
    Those aren't performed regularly, though (a normal "git gc" doesn't
    use --stale-fix), so they're not really worth measuring. There's a
    low chance of regressing that caller, since the use of bitmaps is
    totally transparent from the caller's perspective.

  - The bitmap case could actually get away without creating a "struct
    object", and instead the caller could just look up each object id in
    the bitmap result. However, this would be a marginal improvement in
    runtime, and it would make the callers much more complicated. They'd
    have to handle both the bitmap and non-bitmap cases separately, and
    in the case of git-prune, we'd also have to tweak prune_shallow(),
    which relies on our SEEN flags.

  - Because we do create real object structs, we go through a few
    contortions to create ones of the right type. This isn't strictly
    necessary (lookup_unknown_object() would suffice), but it's more
    memory efficient to use the correct types, since we already know
    them.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-02-14 15:25:33 -08:00
Stefan Beller
f86bcc7b2c tree: add repository argument to lookup_tree
Add a repository argument to allow the callers of lookup_tree
to be more specific about which repository to act on. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-06-29 10:43:38 -07:00
Stefan Beller
da14a7ff99 blob: add repository argument to lookup_blob
Add a repository argument to allow the callers of lookup_blob
to be more specific about which repository to act on. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-06-29 10:43:38 -07:00
Stefan Beller
5abddd1eb7 object: add repository argument to lookup_object
Add a repository argument to allow callers of lookup_object to be more
specific about which repository to handle. This is a small mechanical
change; it doesn't change the implementation to handle repositories
other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-06-29 10:43:38 -07:00
Stefan Beller
0df8e96566 cache.h: add repository argument to oid_object_info
Add a repository argument to allow the callers of oid_object_info
to be more specific about which repository to handle. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.

As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.

Signed-off-by: Stefan Beller <sbeller@google.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-26 10:54:27 +09:00
Junio C Hamano
cf0b1793ea Merge branch 'sb/object-store'
Refactoring the internal global data structure to make it possible
to open multiple repositories, work with and then close them.

Rerolled by Duy on top of a separate preliminary clean-up topic.
The resulting structure of the topics looked very sensible.

* sb/object-store: (27 commits)
  sha1_file: allow sha1_loose_object_info to handle arbitrary repositories
  sha1_file: allow map_sha1_file to handle arbitrary repositories
  sha1_file: allow map_sha1_file_1 to handle arbitrary repositories
  sha1_file: allow open_sha1_file to handle arbitrary repositories
  sha1_file: allow stat_sha1_file to handle arbitrary repositories
  sha1_file: allow sha1_file_name to handle arbitrary repositories
  sha1_file: add repository argument to sha1_loose_object_info
  sha1_file: add repository argument to map_sha1_file
  sha1_file: add repository argument to map_sha1_file_1
  sha1_file: add repository argument to open_sha1_file
  sha1_file: add repository argument to stat_sha1_file
  sha1_file: add repository argument to sha1_file_name
  sha1_file: allow prepare_alt_odb to handle arbitrary repositories
  sha1_file: allow link_alt_odb_entries to handle arbitrary repositories
  sha1_file: add repository argument to prepare_alt_odb
  sha1_file: add repository argument to link_alt_odb_entries
  sha1_file: add repository argument to read_info_alternates
  sha1_file: add repository argument to link_alt_odb_entry
  sha1_file: add raw_object_store argument to alt_odb_usable
  pack: move approximate object count to object store
  ...
2018-04-11 13:09:55 +09:00
Stefan Beller
a80d72db2a object-store: move packed_git and packed_git_mru to object store
In a process with multiple repositories open, packfile accessors
should be associated to a single repository and not shared globally.
Move packed_git and packed_git_mru into the_repository and adjust
callers to reflect this.

[nd: while at there, wrap access to these two fields in get_packed_git()
and get_packed_git_mru(). This allows us to lazily initialize these
fields without caller doing that explicitly]

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-03-26 10:05:46 -07:00
brian m. carlson
abef9020e3 sha1_file: convert sha1_object_info* to object_id
Convert sha1_object_info and sha1_object_info_extended to take pointers
to struct object_id and rename them to use "oid" instead of "sha1" in
their names.  Update the declaration and definition and apply the
following semantic patch, plus the standard object_id transforms:

@@
expression E1, E2;
@@
- sha1_object_info(E1.hash, E2)
+ oid_object_info(&E1, E2)

@@
expression E1, E2;
@@
- sha1_object_info(E1->hash, E2)
+ oid_object_info(E1, E2)

@@
expression E1, E2, E3;
@@
- sha1_object_info_extended(E1.hash, E2, E3)
+ oid_object_info_extended(&E1, E2, E3)

@@
expression E1, E2, E3;
@@
- sha1_object_info_extended(E1->hash, E2, E3)
+ oid_object_info_extended(E1, E2, E3)

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-03-14 09:23:49 -07:00
Brandon Williams
debca9d2fe object: rename function 'typename' to 'type_name'
Rename C++ keyword in order to bring the codebase closer to being able
to be compiled with a C++ compiler.

Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-02-14 13:10:05 -08:00
Junio C Hamano
8a044c7f1d Merge branch 'nd/prune-in-worktree'
"git gc" and friends when multiple worktrees are used off of a
single repository did not consider the index and per-worktree refs
of other worktrees as the root for reachability traversal, making
objects that are in use only in other worktrees to be subject to
garbage collection.

* nd/prune-in-worktree:
  refs.c: reindent get_submodule_ref_store()
  refs.c: remove fallback-to-main-store code get_submodule_ref_store()
  rev-list: expose and document --single-worktree
  revision.c: --reflog add HEAD reflog from all worktrees
  files-backend: make reflog iterator go through per-worktree reflog
  revision.c: --all adds HEAD from all worktrees
  refs: remove dead for_each_*_submodule()
  refs.c: move for_each_remote_ref_submodule() to submodule.c
  revision.c: use refs_for_each*() instead of for_each_*_submodule()
  refs: add refs_head_ref()
  refs: move submodule slash stripping code to get_submodule_ref_store
  refs.c: refactor get_submodule_ref_store(), share common free block
  revision.c: --indexed-objects add objects from all worktrees
  revision.c: refactor add_index_objects_to_pending()
  refs.c: use is_dir_sep() in resolve_gitlink_ref()
  revision.h: new flag in struct rev_info wrt. worktree-related refs
2017-09-19 10:47:53 +09:00
Nguyễn Thái Ngọc Duy
d0c39a49cc revision.c: --all adds HEAD from all worktrees
Unless single_worktree is set, --all now adds HEAD from all worktrees.

Since reachable.c code does not use setup_revisions(), we need to call
other_head_refs_submodule() explicitly there to have the same effect on
"git prune", so that we won't accidentally delete objects needed by some
other HEADs.

A new FIXME is added because we would need something like

    int refs_other_head_refs(struct ref_store *, each_ref_fn, cb_data);

in addition to other_head_refs() to handle it, which might require

    int get_submodule_worktrees(const char *submodule, int flags);

It could be a separate topic to reduce the scope of this one.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-24 14:56:43 -07:00
Jonathan Tan
7709f468fd pack: move for_each_packed_object()
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-08-23 15:12:07 -07:00
Junio C Hamano
6b526ced6f Merge branch 'bc/object-id'
Conversion from uchar[20] to struct object_id continues.

* bc/object-id: (53 commits)
  object: convert parse_object* to take struct object_id
  tree: convert parse_tree_indirect to struct object_id
  sequencer: convert do_recursive_merge to struct object_id
  diff-lib: convert do_diff_cache to struct object_id
  builtin/ls-tree: convert to struct object_id
  merge: convert checkout_fast_forward to struct object_id
  sequencer: convert fast_forward_to to struct object_id
  builtin/ls-files: convert overlay_tree_on_cache to object_id
  builtin/read-tree: convert to struct object_id
  sha1_name: convert internals of peel_onion to object_id
  upload-pack: convert remaining parse_object callers to object_id
  revision: convert remaining parse_object callers to object_id
  revision: rename add_pending_sha1 to add_pending_oid
  http-push: convert process_ls_object and descendants to object_id
  refs/files-backend: convert many internals to struct object_id
  refs: convert struct ref_update to use struct object_id
  ref-filter: convert some static functions to struct object_id
  Convert struct ref_array_item to struct object_id
  Convert the verify_pack callback to struct object_id
  Convert lookup_tag to struct object_id
  ...
2017-05-29 12:34:43 +09:00
brian m. carlson
c251c83df2 object: convert parse_object* to take struct object_id
Make parse_object, parse_object_or_die, and parse_object_buffer take a
pointer to struct object_id.  Remove the temporary variables inserted
earlier, since they are no longer necessary.  Transform all of the
callers using the following semantic patch:

@@
expression E1;
@@
- parse_object(E1.hash)
+ parse_object(&E1)

@@
expression E1;
@@
- parse_object(E1->hash)
+ parse_object(E1)

@@
expression E1, E2;
@@
- parse_object_or_die(E1.hash, E2)
+ parse_object_or_die(&E1, E2)

@@
expression E1, E2;
@@
- parse_object_or_die(E1->hash, E2)
+ parse_object_or_die(E1, E2)

@@
expression E1, E2, E3, E4, E5;
@@
- parse_object_buffer(E1.hash, E2, E3, E4, E5)
+ parse_object_buffer(&E1, E2, E3, E4, E5)

@@
expression E1, E2, E3, E4, E5;
@@
- parse_object_buffer(E1->hash, E2, E3, E4, E5)
+ parse_object_buffer(E1, E2, E3, E4, E5)

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-08 15:12:58 +09:00
brian m. carlson
740ee055c6 Convert lookup_tree to struct object_id
Convert the lookup_tree function to take a pointer to struct object_id.

The commit was created with manual changes to tree.c, tree.h, and
object.c, plus the following semantic patch:

@@
@@
- lookup_tree(EMPTY_TREE_SHA1_BIN)
+ lookup_tree(&empty_tree_oid)

@@
expression E1;
@@
- lookup_tree(E1.hash)
+ lookup_tree(&E1)

@@
expression E1;
@@
- lookup_tree(E1->hash)
+ lookup_tree(E1)

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-08 15:12:57 +09:00
brian m. carlson
3aca1fc6c9 Convert lookup_blob to struct object_id
Convert lookup_blob to take a pointer to struct object_id.

The commit was created with manual changes to blob.c and blob.h, plus
the following semantic patch:

@@
expression E1;
@@
- lookup_blob(E1.hash)
+ lookup_blob(&E1)

@@
expression E1;
@@
- lookup_blob(E1->hash)
+ lookup_blob(E1)

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-05-08 15:12:57 +09:00
Johannes Schindelin
dddbad728c timestamp_t: a new data type for timestamps
Git's source code assumes that unsigned long is at least as precise as
time_t. Which is incorrect, and causes a lot of problems, in particular
where unsigned long is only 32-bit (notably on Windows, even in 64-bit
versions).

So let's just use a more appropriate data type instead. In preparation
for this, we introduce the new `timestamp_t` data type.

By necessity, this is a very, very large patch, as it has to replace all
timestamps' data type in one go.

As we will use a data type that is not necessarily identical to `time_t`,
we need to be very careful to use `time_t` whenever we interact with the
system functions, and `timestamp_t` everywhere else.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-04-27 13:07:39 +09:00
brian m. carlson
76c1d9a096 Convert object iteration callbacks to struct object_id
Convert each_loose_object_fn and each_packed_object_fn to take a pointer
to struct object_id.  Update the various callbacks.  Convert several
40-based constants to use GIT_SHA1_HEXSZ.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-02-22 10:12:15 -08:00
Nguyễn Thái Ngọc Duy
9a3acba1ca reachable.c: use error_errno()
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-05-09 12:29:08 -07:00
Jeff King
de1e67d070 list-objects: pass full pathname to callbacks
When we find a blob at "a/b/c", we currently pass this to
our show_object_fn callbacks as two components: "a/b/" and
"c". Callbacks which want the full value then call
path_name(), which concatenates the two. But this is an
inefficient interface; the path is a strbuf, and we could
simply append "c" to it temporarily, then roll back the
length, without creating a new copy.

So we could improve this by teaching the callsites of
path_name() this trick (and there are only 3). But we can
also notice that no callback actually cares about the
broken-down representation, and simply pass each callback
the full path "a/b/c" as a string. The callback code becomes
even simpler, then, as we do not have to worry about freeing
an allocated buffer, nor rolling back our modification to
the strbuf.

This is theoretically less efficient, as some callbacks
would not bother to format the final path component. But in
practice this is not measurable. Since we use the same
strbuf over and over, our work to grow it is amortized, and
we really only pay to memcpy a few bytes.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-12 12:51:17 -08:00
Jeff King
bd64516aca list-objects: drop name_path entirely
In the previous commit, we left name_path as a thin wrapper
around a strbuf. This patch drops it entirely. As a result,
every show_object_fn callback needs to be adjusted. However,
none of their code needs to be changed at all, because the
only use was to pass it to path_name(), which now handles
the bare strbuf.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-12 12:51:15 -08:00
Junio C Hamano
1018f3eea4 Merge branch 'js/gc-with-stale-symref'
"git gc" used to barf when a symbolic ref has gone dangling
(e.g. the branch that used to be your upstream's default when you
cloned from it is now gone, and you did "fetch --prune").

* js/gc-with-stale-symref:
  pack-objects: do not get distracted by broken symrefs
  gc: demonstrate failure with stale remote HEAD
2015-10-15 15:43:51 -07:00
Johannes Schindelin
14886b40c5 pack-objects: do not get distracted by broken symrefs
It is quite possible for, say, a remote HEAD to become broken, e.g.
when the default branch was renamed.

We should still be able to pack our objects when such a thing happens;
simply ignore broken symrefs (because they cannot matter for the packing
process anyway).

This fixes https://github.com/git-for-windows/git/issues/423

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-10-08 12:42:06 -07:00
Michael Haggerty
635170f2bb add_one_ref(): rewrite to take an object_id argument
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-05-25 12:19:34 -07:00
Michael Haggerty
2b2a5be394 each_ref_fn: change to take an object_id parameter
Change typedef each_ref_fn to take a "const struct object_id *oid"
parameter instead of "const unsigned char *sha1".

To aid this transition, implement an adapter that can be used to wrap
old-style functions matching the old typedef, which is now called
"each_ref_sha1_fn"), and make such functions callable via the new
interface. This requires the old function and its cb_data to be
wrapped in a "struct each_ref_fn_sha1_adapter", and that object to be
used as the cb_data for an adapter function, each_ref_fn_adapter().

This is an enormous diff, but most of it consists of simple,
mechanical changes to the sites that call any of the "for_each_ref"
family of functions. Subsequent to this change, the call sites can be
rewritten one by one to use the new interface.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-05-25 12:19:27 -07:00
Jeff King
1385bb7ba3 reachable: only mark local objects as recent
When pruning and repacking a repository that has an
alternate object store configured, we may traverse a large
number of objects in the alternate. This serves no purpose,
and may be expensive to do. A longer explanation is below.

Commits d3038d2 and abcb865 taught prune and pack-objects
(respectively) to treat "recent" objects as tips for
reachability, so that we keep whole chunks of history. They
built on the object traversal in 660c889 (sha1_file: add
for_each iterators for loose and packed objects,
2014-10-15), which covers both local and alternate objects.

In both cases, covering alternate objects is unnecessary, as
both commands can only drop objects from the local
repository. In the case of prune, we traverse only the local
object directory. And in the case of repacking, while we may
or may not include local objects in our pack, we will never
reach into the alternate with "repack -d". The "-l" option
is only a question of whether we are migrating objects from
the alternate into our repository, or leaving them
untouched.

It is possible that we may drop an object that is depended
upon by another object in the alternate. For example,
imagine two repositories, A and B, with A pointing to B as
an alternate. Now imagine a commit that is in B which
references a tree that is only in A. Traversing from recent
objects in B might prevent A from dropping that tree. But
this case isn't worth covering. Repo B should take
responsibility for its own objects. It would never have had
the commit in the first place if it did not also have the
tree, and assuming it is using the same "keep recent chunks
of history" scheme, then it would itself keep the tree, as
well.

So checking the alternate objects is not worth doing, and
come with a significant performance impact. In both cases,
we skip any recent objects that have already been marked
SEEN (i.e., that we know are already reachable for prune, or
included in the pack for a repack). So there is a slight
waste of time in opening the alternate packs at all, only to
notice that we have already considered each object. But much
worse, the alternate repository may have a large number of
objects that are not reachable from the local repository at
all, and we end up adding them to the traversal.

We can fix this by considering only local unseen objects.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2015-04-20 13:09:27 -07:00
Jeff King
1be111d88f reachable: use revision machinery's --indexed-objects code
This does the same thing as our custom code, so let's not
repeat ourselves.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-19 15:07:07 -07:00
Jeff King
abcb86553d pack-objects: match prune logic for discarding objects
A recent commit taught git-prune to keep non-recent objects
that are reachable from recent ones. However, pack-objects,
when loosening unreachable objects, tries to optimize out
the write in the case that the object will be immediately
pruned. It now gets this wrong, since its rule does not
reflect the new prune code (and this can be seen by running
t6501 with a strategically placed repack).

Let's teach pack-objects similar logic.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-16 10:10:43 -07:00
Jeff King
d3038d22f9 prune: keep objects reachable from recent objects
Our current strategy with prune is that an object falls into
one of three categories:

  1. Reachable (from ref tips, reflogs, index, etc).

  2. Not reachable, but recent (based on the --expire time).

  3. Not reachable and not recent.

We keep objects from (1) and (2), but prune objects in (3).
The point of (2) is that these objects may be part of an
in-progress operation that has not yet updated any refs.

However, it is not always the case that objects for an
in-progress operation will have a recent mtime. For example,
the object database may have an old copy of a blob (from an
abandoned operation, a branch that was deleted, etc). If we
create a new tree that points to it, a simultaneous prune
will leave our tree, but delete the blob. Referencing that
tree with a commit will then work (we check that the tree is
in the object database, but not that all of its referred
objects are), as will mentioning the commit in a ref. But
the resulting repo is corrupt; we are missing the blob
reachable from a ref.

One way to solve this is to be more thorough when
referencing a sha1: make sure that not only do we have that
sha1, but that we have objects it refers to, and so forth
recursively. The problem is that this is very expensive.
Creating a parent link would require traversing the entire
object graph!

Instead, this patch pushes the extra work onto prune, which
runs less frequently (and has to look at the whole object
graph anyway). It creates a new category of objects: objects
which are not recent, but which are reachable from a recent
object. We do not prune these objects, just like the
reachable and recent ones.

This lets us avoid the recursive check above, because if we
have an object, even if it is unreachable, we should have
its referent. We can make a simple inductive argument that
with this patch, this property holds (that there are no
objects with missing referents in the repository):

  0. When we have no objects, we have nothing to refer or be
     referred to, so the property holds.

  1. If we add objects to the repository, their direct
     referents must generally exist (e.g., if you create a
     tree, the blobs it references must exist; if you create
     a commit to point at the tree, the tree must exist).
     This is already the case before this patch. And it is
     not 100% foolproof (you can make bogus objects using
     `git hash-object`, for example), but it should be the
     case for normal usage.

     Therefore for any sequence of object additions, the
     property will continue to hold.

  2. If we remove objects from the repository, then we will
     not remove a child object (like a blob) if an object
     that refers to it is being kept. That is the part
     implemented by this patch.

     Note, however, that our reachability check and the
     actual pruning are not atomic. So it _is_ still
     possible to violate the property (e.g., an object
     becomes referenced just as we are deleting it). This
     patch is shooting for eliminating problems where the
     mtimes of dependent objects differ by hours or days,
     and one is dropped without the other. It does nothing
     to help with short races.

Naively, the simplest way to implement this would be to add
all recent objects as tips to the reachability traversal.
However, this does not perform well. In a recently-packed
repository, all reachable objects will also be recent, and
therefore we have to look at each object twice. This patch
instead performs the reachability traversal, then follows up
with a second traversal for recent objects, skipping any
that have already been marked.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-16 10:10:42 -07:00
Jeff King
3725427945 reachable: mark index blobs as SEEN
When we mark all reachable objects for pruning, that
includes blobs mentioned by the index. However, we do not
mark these with the SEEN flag, as we do for objects that we
find by traversing (we also do not add them to the pending
list, but that is because there is nothing further to
traverse with them).

This doesn't cause any problems with prune, because it
checks only that the object exists in the global object
hash, and not its flags. However, let's mark these objects
to be consistent and avoid any later surprises.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-16 10:10:40 -07:00
Jeff King
718ccc9731 reachable: reuse revision.c "add all reflogs" code
We want to add all reflog entries as tips for finding
reachable objects. The revision machinery can already do
this (to support "rev-list --reflog"); we can reuse that
code.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-16 10:10:38 -07:00
Jeff King
5f78a431ab reachable: use traverse_commit_list instead of custom walk
To find the set of reachable objects, we add a bunch of
possible sources to our rev_info, call prepare_revision_walk,
and then launch into a custom walker that handles each
object top. This is a subset of what traverse_commit_list
does, so we can just reuse that code (it can also handle
more complex cases like UNINTERESTING commits and pathspecs,
but we don't use those features).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-10-16 10:10:38 -07:00
Max Kirillov
c40fdd01dd reachable.c: add HEAD to reachability starting commits
HEAD is not explicitly used as a starting commit for
calculating reachability, so if it's detached and reflogs
are disabled it may be pruned.

Add tests which demonstrate it. Test 'prune: prune former HEAD after checking
out branch' also reverts changes to repository.

Signed-off-by: Max Kirillov <max@max630.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-09-03 10:47:44 -07:00
Jeff King
6e454b9a31 clear parsed flag when we free tree buffers
Many code paths will free a tree object's buffer and set it
to NULL after finishing with it in order to keep memory
usage down during a traversal. However, out of 8 sites that
do this, only one actually unsets the "parsed" flag back.
Those sites that don't are setting a trap for later users of
the tree object; even after calling parse_tree, the buffer
will remain NULL, causing potential segfaults.

It is not known whether this is triggerable in the current
code. Most commands do not do an in-memory traversal
followed by actually using the objects again. However, it
does not hurt to be safe for future callers.

In most cases, we can abstract this out to a
"free_tree_buffer" helper. However, there are two
exceptions:

  1. The fsck code relies on the parsed flag to know that we
     were able to parse the object at one point. We can
     switch this to using a flag in the "flags" field.

  2. The index-pack code sets the buffer to NULL but does
     not free it (it is freed by a caller). We should still
     unset the parsed flag here, but we cannot use our
     helper, as we do not want to free the buffer.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-06-06 10:29:12 -07:00
Jeff King
f7892d1817 use parse_object_or_die instead of die("bad object")
Some call-sites do:

  o = parse_object(sha1);
  if (!o)
	  die("bad object %s", some_name);

We can now handle that as a one-liner, and get more
consistent output.

In the third case of this patch, it looks like we are losing
information, as the existing message also outputs the sha1
hex; however, parse_object will already have written a more
specific complaint about the sha1, so there is no point in
repeating it here.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-03-17 12:52:14 -07:00
Jeff King
0b26abc0f5 reachable: per-object progress
The current progress code really just counts commits.
This patch makes it count all objects, giving us a "total"
count close to what a repack would show. This is nice when
using "git gc", which will usually have just repacked the
whole repo.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-07 22:12:19 -08:00
Nguyễn Thái Ngọc Duy
dc347195cc prune: show progress while marking reachable objects
prune already shows progress meter while pruning. The marking part may
take a few seconds or more, depending on repository size. Show
progress meter during this time too.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-11-07 22:12:19 -08:00
Johannes Schindelin
c0aa335c95 Remove unused variables
Noticed by gcc 4.6.0.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-03-22 11:43:27 -07:00
Thiago Farina
3cd474599f object.h: Add OBJECT_ARRAY_INIT macro and make use of it.
Signed-off-by: Thiago Farina <tfransosi@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-08-29 22:42:49 -07:00
Björn Steinbrink
de551d472e process_{tree,blob}: Remove useless xstrdup calls
The name of the processed object was duplicated for passing it to
add_object(), but that already calls path_name, which allocates a new
string anyway. So the memory allocated by the xstrdup calls just went
nowhere, leaking memory.

This reduces the RSS usage for a "rev-list --all --objects" by about 10% on
the gentoo repo (fully packed) as well as linux-2.6.git:

    gentoo:
                    | old           | new
    ----------------|-------------------------------
    RSS             |       1537284 |       1388408
    VSZ             |       1816852 |       1667952
    time elapsed    |       1:49.62 |       1:48.99
    min. page faults|        417178 |        379919

    linux-2.6.git:
                    | old           | new
    ----------------|-------------------------------
    RSS             |        324452 |        292996
    VSZ             |        491792 |        460376
    time elapsed    |       0:14.53 |       0:14.28
    min. page faults|         89360 |         81613

Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-04-08 22:58:43 -07:00
Junio C Hamano
ee4f06c0a6 Merge branch 'mk/maint-parse-careful'
* mk/maint-parse-careful:
  peel_onion: handle NULL
  check return value from parse_commit() in various functions
  parse_commit: don't fail, if object is NULL
  revision.c: handle tag->tagged == NULL
  reachable.c::process_tree/blob: check for NULL
  process_tag: handle tag->tagged == NULL
  check results of parse_commit in merge_bases
  list-objects.c::process_tree/blob: check for NULL
  reachable.c::add_one_tree: handle NULL from lookup_tree
  mark_blob/tree_uninteresting: check for NULL
  get_sha1_oneline: check return value of parse_object
  read_object_with_reference: don't read beyond the buffer
2008-02-18 20:56:01 -08:00
Martin Koegler
f7de5a56b7 reachable.c::process_tree/blob: check for NULL
As these functions are directly called with the result
from lookup_tree/blob, they must handle NULL.

Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-18 19:25:26 -08:00
Martin Koegler
cc36934791 process_tag: handle tag->tagged == NULL
Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-18 19:25:26 -08:00
Martin Koegler
c34066358a reachable.c::add_one_tree: handle NULL from lookup_tree
Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-18 19:25:22 -08:00
Martin Koegler
3d51e1b5b8 check return code of prepare_revision_walk
A failure in prepare_revision_walk can be caused by
a not parseable object.

Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-17 23:51:12 -08:00
Linus Torvalds
7a51ed66f6 Make on-disk index representation separate from in-core one
This converts the index explicitly on read and write to its on-disk
format, allowing the in-core format to contain more flags, and be
simpler.

In particular, the in-core format is now host-endian (as opposed to the
on-disk one that is network endian in order to be able to be shared
across machines) and as a result we can dispense with all the
htonl/ntohl on accesses to the cache_entry fields.

This will make it easier to make use of various temporary flags that do
not exist in the on-disk format.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-01-21 12:44:31 -08:00
Junio C Hamano
b941ffac50 Merge branch 'maint'
* maint:
  Make git-prune submodule aware (and fix a SEGFAULT in the process)
2007-07-02 17:12:48 -07:00
Andy Parkins
8d2244ba74 Make git-prune submodule aware (and fix a SEGFAULT in the process)
I ran git-prune on a repository and got this:

 $ git-prune
 error: Object 228f8065b930120e35fc0c154c237487ab02d64a is a blob, not a commit
 Segmentation fault (core dumped)

This repository was a strange one in that it was being used to provide
its own submodule.  That is, the repository was cloned into a
subdirectory, an independent branch checked out in that subdirectory,
and then it was marked as a submodule.  git-prune then failed in the
above manner.

The problem was that git-prune was not submodule aware in two areas.

Linus said:

 > So what happens is that something traverses a tree object, looks at each
 > entry, sees that it's not a tree, and tries to look it up as a blob. But
 > subprojects are commits, not blobs, and then when you look at the object
 > more closely, you get the above kind of object type confusion.

and included a patch to add an S_ISGITLINK() test to reachable.c's
process_tree() function.  That fixed the first git-prune error, and
stopped it from trying to process the gitlink entries in trees as if
they were pointers to other trees (and of course failing, because
gitlinks _aren't_ trees).  That part of this patch is his.

The second area is add_cache_refs().  This is called before starting the
reachability analysis, and was calling lookup_blob() on every object
hash found in the index.  However, it is no longer true that every hash
in the index is a pointer to a blob, some of them are gitlinks, and are
not backed by any object at all, they are commits in another repository.
Normally this bug was not causing any problems, but in the case of the
self-referencing repository described above, it meant that the gitlink
hash was being marked as being of type OBJ_BLOB by add_cache_refs() call
to lookup_blob().  Then later, because that hash was also pointed to by
a ref, add_one_ref() would treat it as a commit; lookup_commit() would
return a NULL because that object was already noted as being an
OBJ_BLOB, not an OBJ_COMMIT; and parse_commit_buffer() would SEGFAULT on
that NULL pointer.

The fix made by this patch is to not blindly call lookup_blob() in
reachable.c's add_cache_refs(), and instead skip any index entries that
are S_ISGITLINK().

Signed-off-by: Andy Parkins <andyparkins@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-07-02 16:41:18 -07:00
Linus Torvalds
6fda5e5180 Initialize tree descriptors with a helper function rather than by hand.
This removes slightly more lines than it adds, but the real reason for
doing this is that future optimizations will require more setup of the
tree descriptor, and so we want to do it in one place.

Also renamed the "desc.buf" field to "desc.buffer" just to trigger
compiler errors for old-style manual initializations, making sure I
didn't miss anything.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-03-21 10:21:57 -07:00