Commit Graph

1173 Commits

Author SHA1 Message Date
Nguyễn Thái Ngọc Duy
5fc2fc8fa2 read-cache: split-index mode
This split-index mode is designed to keep write cost proportional to
the number of changes the user has made, not the size of the work
tree. (Read cost is another matter, to be dealt separately.)

This mode stores index info in a pair of $GIT_DIR/index and
$GIT_DIR/sharedindex.<SHA-1>. sharedindex is large and unchanged over
time while "index" is smaller and updated often. Format details are in
index-format.txt, although not everything is implemented in this
patch.

Shared indexes are not automatically removed, because it's unclear if
the shared index is needed by any (even temporary) indexes by just
looking at it. After a while you'll collect stale shared indexes. The
good news is one shared index is useable for long, until
$GIT_DIR/index becomes too big and sluggish that the new shared index
must be created.

The safest way to clean shared indexes is to turn off split index
mode, so shared files are all garbage, delete them all, then turn on
split index mode again.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-06-13 11:49:39 -07:00
Nguyễn Thái Ngọc Duy
e93021b20a read-cache: save index SHA-1 after reading
Also update SHA-1 after writing. If we do not do that, the second
read_index() will see "initialized" variable already set and not read
.git/index again, which is fine, except istate->sha1 now has a stale
value.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-06-13 11:49:39 -07:00
Nguyễn Thái Ngọc Duy
d4a2024aef entry.c: update cache_changed if refresh_cache is set in checkout_entry()
Other fill_stat_cache_info() is on new entries, which should set
CE_ENTRY_ADDED in cache_changed, so we're safe.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-06-13 11:49:39 -07:00
Nguyễn Thái Ngọc Duy
a5400efe29 cache-tree: mark istate->cache_changed on cache tree invalidation
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-06-13 11:49:39 -07:00
Nguyễn Thái Ngọc Duy
6c306a34ee resolve-undo: be specific what part of the index has changed
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-06-13 11:49:38 -07:00
Nguyễn Thái Ngọc Duy
e636a7b4d0 read-cache: be specific what part of the index has changed
cache entry additions, removals and modifications are separated
out. The rest of changes are still in the catch-all flag
SOMETHING_CHANGED, which would be more specific later.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-06-13 11:49:38 -07:00
Nguyễn Thái Ngọc Duy
ce51bf09f8 read-cache: store in-memory flags in the first 12 bits of ce_flags
We're running out of room for in-memory flags. But since b60e188
(Strip namelen out of ce_flags into a ce_namelen field - 2012-07-11),
we copy the namelen (first 12 bits) to ce_namelen field. So those bits
are free to use. Just make sure we do not accidentally write any
in-memory flags back.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-06-13 11:49:38 -07:00
Nguyễn Thái Ngọc Duy
626f35c893 read-cache: relocate and unexport commit_locked_index()
This function is now only used by write_locked_index(). Move it to
read-cache.c (because read-cache.c will need to be aware of
alternate_index_output later) and unexport it.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-06-13 11:49:38 -07:00
Nguyễn Thái Ngọc Duy
03b8664772 read-cache: new API write_locked_index instead of write_index/write_cache
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-06-13 11:49:10 -07:00
Junio C Hamano
b6de0c633e Merge branch 'nd/tag-version-sort'
Allow v1.9.0 sorted before v1.10.0 in "git tag --list" output.

* nd/tag-version-sort:
  tag: support --sort=<spec>
2014-03-21 12:47:39 -07:00
Junio C Hamano
3e30cb0fbf Merge branch 'mh/replace-refs-variable-rename'
* mh/replace-refs-variable-rename:
  Document some functions defined in object.c
  Add docstrings for lookup_replace_object() and do_lookup_replace_object()
  rename read_replace_refs to check_replace_refs
2014-03-14 14:27:06 -07:00
Junio C Hamano
060be00621 Merge branch 'mh/object-code-cleanup'
* mh/object-code-cleanup:
  sha1_file.c: document a bunch of functions defined in the file
  sha1_file_name(): declare to return a const string
  find_pack_entry(): document last_found_pack
  replace_object: use struct members instead of an array
2014-03-14 14:26:29 -07:00
Junio C Hamano
3c83b080e4 Merge branch 'jk/commit-dates-parsing-fix'
Tighten codepaths that parse timestamps in commit objects.

* jk/commit-dates-parsing-fix:
  show_ident_date: fix tz range check
  log: do not segfault on gmtime errors
  log: handle integer overflow in timestamps
  date: check date overflow against time_t
  fsck: report integer overflow in author timestamps
  t4212: test bogus timestamps with git-log
2014-03-14 14:25:44 -07:00
Junio C Hamano
08f36302b5 Merge branch 'ks/config-file-stdin'
"git config" learned to read from the standard input when "-" is
given as the value to its "--file" parameter (attempting an
operation to update the configuration in the standard input of
course is rejected).

* ks/config-file-stdin:
  config: teach "git config --file -" to read from the standard input
  config: change git_config_with_options() interface
  builtin/config.c: rename check_blob_write() -> check_write()
  config: disallow relative include paths from blobs
2014-03-14 14:24:40 -07:00
Junio C Hamano
053a6b1807 Merge branch 'jn/add-2.0-u-A-sans-pathspec'
"git add -u" and "git add -A" without any pathspec is a tree-wide
operation now, even when they are run in a subdirectory of the
working tree.
2014-03-07 15:14:02 -08:00
Junio C Hamano
4c4ac4db2c Merge branch 'nd/daemonize-gc'
Allow running "gc --auto" in the background.

* nd/daemonize-gc:
  gc: config option for running --auto in background
  daemon: move daemonize() to libgit.a
2014-03-05 15:06:39 -08:00
Michael Haggerty
1f91e79cf6 Add docstrings for lookup_replace_object() and do_lookup_replace_object()
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-28 13:17:56 -08:00
Nguyễn Thái Ngọc Duy
9ef176b55c tag: support --sort=<spec>
--sort=version:refname (or --sort=v:refname for short) sorts tags as
if they are versions. --sort=-refname reverses the order (with or
without ":version").

versioncmp() is copied from string/strverscmp.c in glibc commit
ee9247c38a8def24a59eb5cfb7196a98bef8cfdc, reformatted to Git coding
style. The implementation is under LGPL-2.1 and according to [1] I can
relicense it to GPLv2.

[1] http://www.gnu.org/licenses/gpl-faq.html#AllCompatibility

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-27 14:04:05 -08:00
Junio C Hamano
0f9e62e084 Merge branch 'jk/pack-bitmap'
Borrow the bitmap index into packfiles from JGit to speed up
enumeration of objects involved in a commit range without having to
fully traverse the history.

* jk/pack-bitmap: (26 commits)
  ewah: unconditionally ntohll ewah data
  ewah: support platforms that require aligned reads
  read-cache: use get_be32 instead of hand-rolled ntoh_l
  block-sha1: factor out get_be and put_be wrappers
  do not discard revindex when re-preparing packfiles
  pack-bitmap: implement optional name_hash cache
  t/perf: add tests for pack bitmaps
  t: add basic bitmap functionality tests
  count-objects: recognize .bitmap in garbage-checking
  repack: consider bitmaps when performing repacks
  repack: handle optional files created by pack-objects
  repack: turn exts array into array-of-struct
  repack: stop using magic number for ARRAY_SIZE(exts)
  pack-objects: implement bitmap writing
  rev-list: add bitmap mode to speed up object lists
  pack-objects: use bitmaps when packing objects
  pack-objects: split add_object_entry
  pack-bitmap: add support for bitmap indexes
  documentation: add documentation for the bitmap format
  ewah: compressed bitmap implementation
  ...
2014-02-27 14:01:48 -08:00
Junio C Hamano
8336832ad9 Merge branch 'nd/reset-intent-to-add'
* nd/reset-intent-to-add:
  reset: support "--mixed --intent-to-add" mode
2014-02-27 14:01:40 -08:00
Junio C Hamano
cbaeafc325 Merge branch 'nd/submodule-pathspec-ending-with-slash'
Allow "git cmd path/", when the 'path' is where a submodule is
bound to the top-level working tree, to match 'path', despite the
extra and unnecessary trailing slash.

* nd/submodule-pathspec-ending-with-slash:
  clean: use cache_name_is_other()
  clean: replace match_pathspec() with dir_path_match()
  pathspec: pass directory indicator to match_pathspec_item()
  match_pathspec: match pathspec "foo/" against directory "foo"
  dir.c: prepare match_pathspec_item for taking more flags
  pathspec: rename match_pathspec_depth() to match_pathspec()
  pathspec: convert some match_pathspec_depth() to dir_path_match()
  pathspec: convert some match_pathspec_depth() to ce_path_match()
2014-02-27 14:01:15 -08:00
Junio C Hamano
156d6ed922 Merge branch 'bk/refresh-missing-ok-in-merge-recursive'
Allow "merge-recursive" to work in an empty (temporary) working
tree again when there are renames involved, correcting an old
regression in 1.7.7 era.

* bk/refresh-missing-ok-in-merge-recursive:
  merge-recursive.c: tolerate missing files while refreshing index
  read-cache.c: extend make_cache_entry refresh flag with options
  read-cache.c: refactor --ignore-missing implementation
  t3030-merge-recursive: test known breakage with empty work tree
2014-02-27 14:01:14 -08:00
Junio C Hamano
d637d1b9a8 Merge branch 'kb/fast-hashmap'
Improvements to our hash table to get it to meet the needs of the
msysgit fscache project, with some nice performance improvements.

* kb/fast-hashmap:
  name-hash: retire unused index_name_exists()
  hashmap.h: use 'unsigned int' for hash-codes everywhere
  test-hashmap.c: drop unnecessary #includes
  .gitignore: test-hashmap is a generated file
  read-cache.c: fix memory leaks caused by removed cache entries
  builtin/update-index.c: cleanup update_one
  fix 'git update-index --verbose --again' output
  remove old hash.[ch] implementation
  name-hash.c: remove cache entries instead of marking them CE_UNHASHED
  name-hash.c: use new hash map implementation for cache entries
  name-hash.c: remove unreferenced directory entries
  name-hash.c: use new hash map implementation for directories
  diffcore-rename.c: use new hash map implementation
  diffcore-rename.c: simplify finding exact renames
  diffcore-rename.c: move code around to prepare for the next patch
  buitin/describe.c: use new hash map implementation
  add a hashtable implementation that supports O(1) removal
  submodule: don't access the .gitmodules cache entry after removing it
2014-02-27 14:01:09 -08:00
Michael Haggerty
d40d535b89 sha1_file.c: document a bunch of functions defined in the file
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-24 16:01:11 -08:00
Eric Sunshine
7b359ea6b3 name-hash: retire unused index_name_exists()
db5360f3f4 (name-hash: refactor polymorphic index_name_exists();
2013-09-17) split index_name_exists() into index_file_exists() and
index_dir_exists() but retained index_name_exists() as a thin wrapper
to avoid disturbing possible in-flight topics. Since this change
landed in 'master' some time ago and there are no in-flight topics
referencing index_name_exists(), retire it.

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-24 15:26:33 -08:00
Nguyễn Thái Ngọc Duy
429bb40abd pathspec: convert some match_pathspec_depth() to ce_path_match()
This helps reduce the number of match_pathspec_depth() call sites and
show how match_pathspec_depth() is used.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-24 14:36:52 -08:00
Brad King
257627268a read-cache.c: extend make_cache_entry refresh flag with options
Convert the make_cache_entry boolean 'refresh' argument to a more
general 'refresh_options' argument.  Pass the value through to the
underlying refresh_cache_ent call.  Add option CE_MATCH_REFRESH to
enable stat refresh.  Update call sites to use the new signature.

Signed-off-by: Brad King <brad.king@kitware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-24 14:31:17 -08:00
Brad King
2e2e7ec1ef read-cache.c: refactor --ignore-missing implementation
Move lstat ENOENT handling from refresh_index to refresh_cache_ent and
activate it with a new CE_MATCH_IGNORE_MISSING option.  This will allow
other call paths into refresh_cache_ent to use the feature.

Signed-off-by: Brad King <brad.king@kitware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-24 14:31:10 -08:00
Jeff King
7ca36d9398 date: check date overflow against time_t
When we check whether a timestamp has overflowed, we check
only against ULONG_MAX, meaning that strtoul has overflowed.
However, we also feed these timestamps to system functions
like gmtime, which expect a time_t. On many systems, time_t
is actually smaller than "unsigned long" (e.g., because it
is signed), and we would overflow when using these
functions.  We don't know the actual size or signedness of
time_t, but we can easily check for truncation with a simple
assignment.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-24 10:12:58 -08:00
Michael Haggerty
30d6c6eabf sha1_file_name(): declare to return a const string
Change the return value of sha1_file_name() to (const char *).
(Callers have no business mucking about here.)  Change callers
accordingly, deleting a few superfluous temporary variables along the
way.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-24 09:10:22 -08:00
Michael Haggerty
afc711b8e1 rename read_replace_refs to check_replace_refs
The semantics of this flag was changed in commit

    e1111cef23 inline lookup_replace_object() calls

but wasn't renamed at the time to minimize code churn.  Rename it now,
and add a comment explaining its use.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-20 14:16:55 -08:00
Kirill A. Shutemov
3caec73b55 config: teach "git config --file -" to read from the standard input
The patch extends git config --file interface to allow read config from
stdin.

Editing stdin or setting value in stdin is an error.

Include by absolute path is allowed in stdin config, but not by relative
path.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-18 16:12:14 -08:00
Kirill A. Shutemov
c8985ce053 config: change git_config_with_options() interface
We're going to have more options for config source.

Let's alter git_config_with_options() interface to accept struct with
all source options.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-18 16:12:13 -08:00
Nguyễn Thái Ngọc Duy
de0957ce2e daemon: move daemonize() to libgit.a
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-02-10 10:46:35 -08:00
Nguyễn Thái Ngọc Duy
b4b313f94a reset: support "--mixed --intent-to-add" mode
When --mixed is used, entries could be removed from index if the
target ref does not have them. When "reset" is used in preparation for
commit spliting (in a dirty worktree), it could be hard to track what
files to be added back. The new option --intent-to-add simplifies it
by marking all removed files intent-to-add.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
2014-02-05 16:44:51 -08:00
Junio C Hamano
d0956cfa8e Merge branch 'mh/safe-create-leading-directories'
Code clean-up and protection against concurrent write access to the
ref namespace.

* mh/safe-create-leading-directories:
  rename_tmp_log(): on SCLD_VANISHED, retry
  rename_tmp_log(): limit the number of remote_empty_directories() attempts
  rename_tmp_log(): handle a possible mkdir/rmdir race
  rename_ref(): extract function rename_tmp_log()
  remove_dir_recurse(): handle disappearing files and directories
  remove_dir_recurse(): tighten condition for removing unreadable dir
  lock_ref_sha1_basic(): if locking fails with ENOENT, retry
  lock_ref_sha1_basic(): on SCLD_VANISHED, retry
  safe_create_leading_directories(): add new error value SCLD_VANISHED
  cmd_init_db(): when creating directories, handle errors conservatively
  safe_create_leading_directories(): introduce enum for return values
  safe_create_leading_directories(): always restore slash at end of loop
  safe_create_leading_directories(): split on first of multiple slashes
  safe_create_leading_directories(): rename local variable
  safe_create_leading_directories(): add explicit "slash" pointer
  safe_create_leading_directories(): reduce scope of local variable
  safe_create_leading_directories(): fix format of "if" chaining
2014-01-27 10:45:33 -08:00
Junio C Hamano
9bb5287098 Merge branch 'mh/retire-ref-fetch-rules'
Code simplification.

* mh/retire-ref-fetch-rules:
  refname_match(): always use the rules in ref_rev_parse_rules
2014-01-27 10:44:07 -08:00
Junio C Hamano
92251b1b5b Merge branch 'nd/shallow-clone'
Fetching from a shallow-cloned repository used to be forbidden,
primarily because the codepaths involved were not carefully vetted
and we did not bother supporting such usage. This attempts to allow
object transfer out of a shallow-cloned repository in a controlled
way (i.e. the receiver become a shallow repository with truncated
history).

* nd/shallow-clone: (31 commits)
  t5537: fix incorrect expectation in test case 10
  shallow: remove unused code
  send-pack.c: mark a file-local function static
  git-clone.txt: remove shallow clone limitations
  prune: clean .git/shallow after pruning objects
  clone: use git protocol for cloning shallow repo locally
  send-pack: support pushing from a shallow clone via http
  receive-pack: support pushing to a shallow clone via http
  smart-http: support shallow fetch/clone
  remote-curl: pass ref SHA-1 to fetch-pack as well
  send-pack: support pushing to a shallow clone
  receive-pack: allow pushes that update .git/shallow
  connected.c: add new variant that runs with --shallow-file
  add GIT_SHALLOW_FILE to propagate --shallow-file to subprocesses
  receive/send-pack: support pushing from a shallow clone
  receive-pack: reorder some code in unpack()
  fetch: add --update-shallow to accept refs that update .git/shallow
  upload-pack: make sure deepening preserves shallow roots
  fetch: support fetching from a shallow repository
  clone: support remote shallow repository
  ...
2014-01-17 12:21:20 -08:00
Michael Haggerty
54457fe509 refname_match(): always use the rules in ref_rev_parse_rules
We used to use two separate rules for the normal ref resolution
dwimming and dwimming done to decide which remote ref to grab.  The
third parameter to refname_match() selected which rules to use.

When these two rules were harmonized in

    2011-11-04 dd621df9cd refs DWIMmery: use the same rule for both "git fetch" and others

, ref_fetch_rules was #defined to avoid potential breakages for
in-flight topics.

It is now safe to remove the backwards-compatibility code, so remove
refname_match()'s third parameter, make ref_rev_parse_rules private to
refs.c, and remove ref_fetch_rules entirely.

Suggested-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-14 13:58:06 -08:00
Junio C Hamano
b2132068c6 Merge branch 'jk/oi-delta-base'
Teach "cat-file --batch" to show delta-base object name for a
packed object that is represented as a delta.

* jk/oi-delta-base:
  cat-file: provide %(deltabase) batch format
  sha1_object_info_extended: provide delta base sha1s
2014-01-10 10:33:11 -08:00
Michael Haggerty
18d37e860d safe_create_leading_directories(): add new error value SCLD_VANISHED
Add a new possible error result that can be returned by
safe_create_leading_directories() and
safe_create_leading_directories_const(): SCLD_VANISHED.  This value
indicates that a file or directory on the path existed at one point
(either it already existed or the function created it), but then it
disappeared.  This probably indicates that another process deleted the
directory while we were working.  If SCLD_VANISHED is returned, the
caller might want to retry the function call, as there is a chance
that a new attempt will succeed.

Why doesn't safe_create_leading_directories() do the retrying
internally?  Because an empty directory isn't really ever safe until
it holds a file.  So even if safe_create_leading_directories() were
absolutely sure that the directory existed before it returned, there
would be no guarantee that the directory still existed when the caller
tried to write something in it.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-06 09:34:22 -08:00
Michael Haggerty
0be0521b23 safe_create_leading_directories(): introduce enum for return values
Instead of returning magic integer values (which a couple of callers
go to the trouble of distinguishing), return values from an enum.  Add
a docstring.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-06 09:34:21 -08:00
Jeff King
5d642e7506 sha1_object_info_extended: provide delta base sha1s
A caller of sha1_object_info_extended technically has enough
information to determine the base sha1 from the results of
the call. It knows the pack, offset, and delta type of the
object, which is sufficient to find the base.

However, the functions to do so are not publicly available,
and the code itself is intimate enough with the pack details
that it should be abstracted away. We could add a public
helper to allow callers to query the delta base separately,
but it is simpler and slightly more efficient to optionally
grab it along with the rest of the object_info data.

For cases where the object is not stored as a delta, we
write the null sha1 into the query field. A careful caller
could check "oi.whence == OI_PACKED && oi.u.packed.is_delta"
before looking at the base sha1, but using the null sha1
provides a simple alternative (and gives a better sanity
check for a non-careful caller than simply returning random
bytes).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-26 11:53:32 -08:00
Christian Couder
de7b5d6218 sha1_object_info_extended(): add an "unsigned flags" parameter
This parameter is not used yet, but it will be used to tell
sha1_object_info_extended() if it should perform object
replacement or not.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-12 11:53:48 -08:00
Christian Couder
bf93eea0f6 sha1_file.c: add lookup_replace_object_extended() to pass flags
Currently, there is only one caller to lookup_replace_object()
that can benefit from passing it some flags, but we expect
that there could be more.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-12 11:53:48 -08:00
Christian Couder
ffe68cf9ac rename READ_SHA1_FILE_REPLACE flag to LOOKUP_REPLACE_OBJECT
The READ_SHA1_FILE_REPLACE flag is more related to using the
lookup_replace_object() function rather than the
read_sha1_file() function.

We also need such a flag to be used with sha1_object_info()
instead of read_sha1_file().

The name LOOKUP_REPLACE_OBJECT is therefore better for this
flag.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-12 11:53:48 -08:00
Nguyễn Thái Ngọc Duy
069c053222 add GIT_SHALLOW_FILE to propagate --shallow-file to subprocesses
This may be needed when a hook is run after a new shallow pack is
received, but .git/shallow is not settled yet. A temporary shallow
file to plug all loose ends should be used instead. GIT_SHALLOW_FILE
is overriden by --shallow-file.

--shallow-file does not work in this case because the hook may spawn
many git subprocesses and the launch commands do not have
--shallow-file as it's a recent addition.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-10 16:14:17 -08:00
Nguyễn Thái Ngọc Duy
58babfffde shallow.c: the 8 steps to select new commits for .git/shallow
Suppose a fetch or push is requested between two shallow repositories
(with no history deepening or shortening). A pack that contains
necessary objects is transferred over together with .git/shallow of
the sender. The receiver has to determine whether it needs to update
.git/shallow if new refs needs new shallow comits.

The rule here is avoid updating .git/shallow by default. But we don't
want to waste the received pack. If the pack contains two refs, one
needs new shallow commits installed in .git/shallow and one does not,
we keep the latter and reject/warn about the former.

Even if .git/shallow update is allowed, we only add shallow commits
strictly necessary for the former ref (remember the sender can send
more shallow commits than necessary) and pay attention not to
accidentally cut the receiver history short (no history shortening is
asked for)

So the steps to figure out what ref need what new shallow commits are:

1. Split the sender shallow commit list into "ours" and "theirs" list
   by has_sha1_file. Those that exist in current repo in "ours", the
   remaining in "theirs".

2. Check the receiver .git/shallow, remove from "ours" the ones that
   also exist in .git/shallow.

3. Fetch the new pack. Either install or unpack it.

4. Do has_sha1_file on "theirs" list again. Drop the ones that fail
   has_sha1_file. Obviously the new pack does not need them.

5. If the pack is kept, remove from "ours" the ones that do not exist
   in the new pack.

6. Walk the new refs to answer the question "what shallow commits,
   both ours and theirs, are required in .git/shallow in order to add
   this ref?". Shallow commits not associated to any refs are removed
   from their respective list.

7. (*) Check reachability (from the current refs) of all remaining
   commits in "ours". Those reachable are removed. We do not want to
   cut any part of our (reachable) history. We only check up
   commits. True reachability test is done by
   check_everything_connected() at the end as usual.

8. Combine the final "ours" and "theirs" and add them all to
   .git/shallow. Install new refs. The case where some hook rejects
   some refs on a push is explained in more detail in the push
   patches.

Of these steps, #6 and #7 are expensive. Both require walking through
some commits, or in the worst case all commits. And we rather avoid
them in at least common case, where the transferred pack does not
contain any shallow commits that the sender advertises. Let's look at
each scenario:

1) the sender has longer history than the receiver

   All shallow commits from the sender will be put into "theirs" list
   at step 1 because none of them exists in current repo. In the
   common case, "theirs" becomes empty at step 4 and exit early.

2) the sender has shorter history than the receiver

   All shallow commits from the sender are likely in "ours" list at
   step 1. In the common case, if the new pack is kept, we could empty
   "ours" and exit early at step 5.

   If the pack is not kept, we hit the expensive step 6 then exit
   after "ours" is emptied. There'll be only a handful of objects to
   walk in fast-forward case. If it's forced update, we may need to
   walk to the bottom.

3) the sender has same .git/shallow as the receiver

   This is similar to case 2 except that "ours" should be emptied at
   step 2 and exit early.

A fetch after "clone --depth=X" is case 1. A fetch after "clone" (from
a shallow repo) is case 3. Luckily they're cheap for the common case.

A push from "clone --depth=X" falls into case 2, which is expensive.
Some more work may be done at the sender/client side to avoid more
work on the server side: if the transferred pack does not contain any
shallow commits, send-pack should not send any shallow commits to the
receive-pack, effectively turning it into a normal push and avoid all
steps.

This patch implements all steps except #3, already handled by
fetch-pack and receive-pack, #6 and #7, which has their own patch due
to their size.

(*) in previous versions step 7 was put before step 3. I reorder it so
    that the common case that keeps the pack does not need to walk
    commits at all. In future if we implement faster commit
    reachability check (maybe with the help of pack bitmaps or commit
    cache), step 7 could become cheap and be moved up before 6 again.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-10 16:14:16 -08:00
Karsten Blees
efc684245b remove old hash.[ch] implementation
Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-11-18 13:04:25 -08:00
Karsten Blees
419a597f64 name-hash.c: remove cache entries instead of marking them CE_UNHASHED
The new hashmap implementation supports remove, so really remove unused
cache entries from the name hashmap instead of just marking them.

The CE_UNHASHED flag and CE_STATE_MASK are no longer needed.

Keep the CE_HASHED flag to prevent adding entries twice.

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-11-18 13:04:24 -08:00