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Author SHA1 Message Date
Ævar Arnfjörð Bjarmason cbe81e653f grep/pcre2: move back to thread-only PCREv2 structures
Change the setup of the "pcre2_general_context" to happen per-thread
in compile_pcre2_pattern() instead of in grep_init().

This change brings it in line with how the rest of the pcre2_* members
in the grep_pat structure are set up.

As noted in the preceding commit the approach 513f2b0bbd (grep: make
PCRE2 aware of custom allocator, 2019-10-16) took to allocate the
pcre2_general_context seems to have been initially based on a
misunderstanding of how PCREv2 memory allocation works.

The approach of creating a global context in grep_init() is just added
complexity for almost zero gain. On my system it's 24 bytes saved
per-thread. For comparison PCREv2 will then go on to allocate at least
a kilobyte for its own thread-local state.

As noted in 6d423dd542 (grep: don't redundantly compile throwaway
patterns under threading, 2017-05-25) the grep code is intentionally
not trying to micro-optimize allocations by e.g. sharing some PCREv2
structures globally, while making others thread-local.

So let's remove this special case and make all of them thread-local
again for simplicity. With this change we could move the
pcre2_{malloc,free} functions around to live closer to their current
use. I'm not doing that here to keep this change small, that cleanup
will be done in a follow-up commit.

See also the discussion in 94da9193a6 (grep: add support for PCRE v2,
2017-06-01) about thread safety, and Johannes's comments[1] to the
effect that we should be doing what this patch is doing.

1. https://lore.kernel.org/git/nycvar.QRO.7.76.6.1908052120302.46@tvgsbejvaqbjf.bet/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-17 16:32:19 -08:00
Ævar Arnfjörð Bjarmason 15c9649730 grep/log: remove hidden --debug and --grep-debug options
Remove the hidden "grep --debug" and "log --grep-debug" options added
in 17bf35a3c7 (grep: teach --debug option to dump the parse tree,
2012-09-13).

At the time these options seem to have been intended to go along with
a documentation discussion and to help the author of relevant tests to
perform ad-hoc debugging on them[1].

Reasons to want this gone:

 1. They were never documented, and the only (rather trivial) use of
    them in our own codebase for testing is something I removed back
    in e01b4dab01 (grep: change non-ASCII -i test to stop using
    --debug, 2017-05-20).

 2. Googling around doesn't show any in-the-wild uses I could dig up,
    and on the Git ML the only mentions after the original discussion
    seem to have been when they came up in unrelated diff contexts, or
    that test commit of mine.

 3. An exception to that is c581e4a749 (grep: under --debug, show
    whether PCRE JIT is enabled, 2019-08-18) where we added the
    ability to dump out when PCREv2 has the JIT in effect.

    The combination of that and my earlier b65abcafc7 (grep: use PCRE
    v2 for optimized fixed-string search, 2019-07-01) means Git prints
    this out in its most common in-the-wild configuration:

        $ git log  --grep-debug --grep=foo --grep=bar --grep=baz --all-match
        pcre2_jit_on=1
        pcre2_jit_on=1
        pcre2_jit_on=1
        [all-match]
        (or
         pattern_body<body>foo
         (or
          pattern_body<body>bar
          pattern_body<body>baz
         )
        )

        $ git grep --debug \( -e foo --and -e bar \) --or -e baz
        pcre2_jit_on=1
        pcre2_jit_on=1
        pcre2_jit_on=1
        (or
         (and
          patternfoo
          patternbar
         )
         patternbaz
        )

I.e. for each pattern we're considering for the and/or/--all-match
etc. debugging we'll now diligently spew out another identical line
saying whether the PCREv2 JIT is on or not.

I think that nobody's complained about that rather glaringly obviously
bad output says something about how much this is used, i.e. it's
not.

The need for this debugging aid for the composed grep/log patterns
seems to have passed, and the desire to dump the JIT config seems to
have been another one-off around the time we had JIT-related issues on
the PCREv2 codepath. That the original author of this debugging
facility seemingly hasn't noticed the bad output since then[2] is
probably some indicator.

1. https://lore.kernel.org/git/cover.1347615361.git.git@drmicha.warpmail.net/
2. https://lore.kernel.org/git/xmqqk1b8x0ac.fsf@gitster-ct.c.googlers.com/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-26 11:36:20 -08:00
Martin Ågren 96313423a7 grep: use designated initializers for `grep_defaults`
In 15fabd1bbd ("builtin/grep.c: make configuration callback more
reusable", 2012-10-09), we learned to fill a `static struct grep_opt
grep_defaults` which we can use as a blueprint for other such structs.

At the time, we didn't consider designated initializers to be widely
useable, but these days, we do. (See, e.g., cbc0f81d96 ("strbuf: use
designated initializers in STRBUF_INIT", 2017-07-10).)

Use designated initializers to let the compiler set up the struct and so
that we don't need to remember to call `init_grep_defaults()`.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-21 14:50:33 -08:00
Martin Ågren 1d3878799f grep: don't set up a "default" repo for grep
`init_grep_defaults()` fills a `static struct grep_opt grep_defaults`.
This struct is then used by `grep_init()` as a blueprint for other such
structs. Notably, `grep_init()` takes a `struct repo *` and assigns it
into the target struct.

As a result, it is unnecessary for us to take a `struct repo *` in
`init_grep_defaults()` as well. We assign it into the default struct and
never look at it again. And in light of how we return early if we have
already set up the default struct, it's not just unnecessary, but is
also a bit confusing: If we are called twice and with different repos,
is it a bug or a feature that we ignore the second repo?

Drop the repo parameter for `init_grep_defaults()`.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-21 14:50:29 -08:00
René Scharfe e30b1525fb grep: handle deref_tag() returning NULL
deref_tag() can return NULL.  Exit gracefully in that case instead
of blindly dereferencing the return value.

.name shouldn't ever be NULL, but grep_object() handles that case
explicitly, so let's be defensive here as well and show the broken
object's ID if it happens to lack a name after all.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-10-12 12:25:14 -07:00
Junio C Hamano 88910c9939 quote_path: give flags parameter to quote_path()
The quote_path() function computes a path (relative to its base
directory) and c-quotes the result if necessary.  Teach it to take a
flags parameter to allow its behaviour to be enriched later.

No behaviour change intended.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-10 10:49:19 -07:00
Junio C Hamano c34d24b8a4 quote_path: rename quote_path_relative() to quote_path()
There is no quote_path_absolute() or anything that causes confusion,
and one of the two large consumers already rename the long name
locally with a preprocessor macro.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-10 10:49:17 -07:00
Elijah Newren eceba53214 dir: fix problematic API to avoid memory leaks
The dir structure seemed to have a number of leaks and problems around
it.  First I noticed that parent_hashmap and recursive_hashmap were
being leaked (though Peff noticed and submitted fixes before me).  Then
I noticed in the previous commit that clear_directory() was only taking
responsibility for a subset of fields within dir_struct, despite the
fact that entries[] and ignored[] we allocated internally to dir.c.
That, of course, resulted in many callers either leaking or haphazardly
trying to free these arrays and their contents.

Digging further, I found that despite the pretty clear documentation
near the top of dir.h that folks were supposed to call clear_directory()
when the user no longer needed the dir_struct, there were four callers
that didn't bother doing that at all.  However, two of them clearly
thought about leaks since they had an UNLEAK(dir) directive, which to me
suggests that the method to free the data was too unclear.  I suspect
the non-obviousness of the API and its holes led folks to avoid it,
which then snowballed into further problems with the entries[],
ignored[], parent_hashmap, and recursive_hashmap problems.

Rename clear_directory() to dir_clear() to be more in line with other
data structures in git, and introduce a dir_init() to handle the
suggested memsetting of dir_struct to all zeroes.  I hope that a name
like "dir_clear()" is more clear, and that the presence of dir_init()
will provide a hint to those looking at the code that they need to look
for either a dir_clear() or a dir_free() and lead them to find
dir_clear().

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-18 17:17:31 -07:00
Junio C Hamano 46b225f153 Merge branch 'jk/strvec'
The argv_array API is useful for not just managing argv but any
"vector" (NULL-terminated array) of strings, and has seen adoption
to a certain degree.  It has been renamed to "strvec" to reduce the
barrier to adoption.

* jk/strvec:
  strvec: rename struct fields
  strvec: drop argv_array compatibility layer
  strvec: update documention to avoid argv_array
  strvec: fix indentation in renamed calls
  strvec: convert remaining callers away from argv_array name
  strvec: convert more callers away from argv_array name
  strvec: convert builtin/ callers away from argv_array name
  quote: rename sq_dequote_to_argv_array to mention strvec
  strvec: rename files from argv-array to strvec
  argv-array: rename to strvec
  argv-array: use size_t for count and alloc
2020-08-10 10:23:57 -07:00
René Scharfe 98c6871fad grep: avoid using oid_to_hex() with parse_object_or_die()
parse_object_or_die() is passed an object ID and a name to show if the
object cannot be parsed.  If the name is NULL then it shows the
hexadecimal object ID.  Use that feature instead of preparing and
passing the hexadecimal representation to the function proactively.
That's shorter and a bit more efficient.

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28 15:26:12 -07:00
Jeff King 22f9b7f3f5 strvec: convert builtin/ callers away from argv_array name
We eventually want to drop the argv_array name and just use strvec
consistently. There's no particular reason we have to do it all at once,
or care about interactions between converted and unconverted bits.
Because of our preprocessor compat layer, the names are interchangeable
to the compiler (so even a definition and declaration using different
names is OK).

This patch converts all of the files in builtin/ to keep the diff to a
manageable size.

The conversion was done purely mechanically with:

  git ls-files '*.c' '*.h' |
  xargs perl -i -pe '
    s/ARGV_ARRAY/STRVEC/g;
    s/argv_array/strvec/g;
  '

and then selectively staging files with "git add builtin/". We'll deal
with any indentation/style fallouts separately.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28 15:02:18 -07:00
Junio C Hamano 6652716200 Merge branch 'dl/opt-callback-cleanup'
Code cleanup.

* dl/opt-callback-cleanup:
  Use OPT_CALLBACK and OPT_CALLBACK_F
2020-05-05 14:54:27 -07:00
Junio C Hamano 6eacc39b6d Merge branch 'en/fill-directory-exponential'
The directory traversal code had redundant recursive calls which
made its performance characteristics exponential with respect to
the depth of the tree, which was corrected.

* en/fill-directory-exponential:
  completion: fix 'git add' on paths under an untracked directory
  Fix error-prone fill_directory() API; make it only return matches
  dir: replace double pathspec matching with single in treat_directory()
  dir: include DIR_KEEP_UNTRACKED_CONTENTS handling in treat_directory()
  dir: replace exponential algorithm with a linear one
  dir: refactor treat_directory to clarify control flow
  dir: fix confusion based on variable tense
  dir: fix broken comment
  dir: consolidate treat_path() and treat_one_path()
  dir: fix simple typo in comment
  t3000: add more testcases testing a variety of ls-files issues
  t7063: more thorough status checking
2020-04-29 16:15:31 -07:00
Denton Liu 203c85339f Use OPT_CALLBACK and OPT_CALLBACK_F
In the codebase, there are many options which use OPTION_CALLBACK in a
plain ol' struct definition. However, we have the OPT_CALLBACK and
OPT_CALLBACK_F macros which are meant to abstract these plain struct
definitions away. These macros are useful as they semantically signal to
developers that these are just normal callback option with nothing fancy
happening.

Replace plain struct definitions of OPTION_CALLBACK with OPT_CALLBACK or
OPT_CALLBACK_F where applicable. The heavy lifting was done using the
following (disgusting) shell script:

	#!/bin/sh

	do_replacement () {
		tr '\n' '\r' |
			sed -e 's/{\s*OPTION_CALLBACK,\s*\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\s*0,\(\s*[^[:space:]}]*\)\s*}/OPT_CALLBACK(\1,\2,\3,\4,\5,\6)/g' |
			sed -e 's/{\s*OPTION_CALLBACK,\s*\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\([^,]*\),\(\s*[^[:space:]}]*\)\s*}/OPT_CALLBACK_F(\1,\2,\3,\4,\5,\6,\7)/g' |
			tr '\r' '\n'
	}

	for f in $(git ls-files \*.c)
	do
		do_replacement <"$f" >"$f.tmp"
		mv "$f.tmp" "$f"
	done

The result was manually inspected and then reformatted to match the
style of the surrounding code. Finally, using
`git grep OPTION_CALLBACK \*.c`, leftover results which were not handled
by the script were manually transformed.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-28 10:47:10 -07:00
Matheus Tavares 45115d8490 grep: follow conventions for printing paths w/ unusual chars
grep does not follow the conventions used by other Git commands when
printing paths that contain unusual characters (as double-quotes or
newlines). Commands such as ls-files, commit, status and diff will:

- Quote and escape unusual pathnames, by default.
- Print names verbatim and unquoted when "-z" is used.

But grep *never* quotes/escapes absolute paths with unusual chars and
*always* quotes/escapes relative ones, even with "-z". Besides being
inconsistent in its own output, the deviation from other Git commands
can be confusing. So let's make it follow the two rules above and add
some tests for this new behavior. Note that, making grep quote/escape
all unusual paths by default, also make it fully compliant with the
core.quotePath configuration, which is currently ignored for absolute
paths.

Reported-by: Greg Hurrell <greg@hurrell.net>
Helped-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-20 13:01:43 -07:00
Elijah Newren 95c11ecc73 Fix error-prone fill_directory() API; make it only return matches
Traditionally, the expected calling convention for the dir.c API was:

    fill_directory(&dir, ..., pathspec)
    foreach entry in dir->entries:
        if (dir_path_match(entry, pathspec))
            process_or_display(entry)

This may have made sense once upon a time, because the fill_directory() call
could use cheap checks to avoid doing full pathspec matching, and an external
caller may have wanted to do other post-processing of the results anyway.
However:

    * this structure makes it easy for users of the API to get it wrong

    * this structure actually makes it harder to understand
      fill_directory() and the functions it uses internally.  It has
      tripped me up several times while trying to fix bugs and
      restructure things.

    * relying on post-filtering was already found to produce wrong
      results; pathspec matching had to be added internally for multiple
      cases in order to get the right results (see commits 404ebceda0
      (dir: also check directories for matching pathspecs, 2019-09-17)
      and 89a1f4aaf7 (dir: if our pathspec might match files under a
      dir, recurse into it, 2019-09-17))

    * it's bad for performance: fill_directory() already has to do lots
      of checks and knows the subset of cases where it still needs to do
      more checks.  Forcing external callers to do full pathspec
      matching means they must re-check _every_ path.

So, add the pathspec matching within the fill_directory() internals, and
remove it from external callers.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-01 11:11:31 -07:00
Junio C Hamano 56ceb64eb0 Merge branch 'mt/threaded-grep-in-object-store'
Traditionally, we avoided threaded grep while searching in objects
(as opposed to files in the working tree) as accesses to the object
layer is not thread-safe.  This limitation is getting lifted.

* mt/threaded-grep-in-object-store:
  grep: use no. of cores as the default no. of threads
  grep: move driver pre-load out of critical section
  grep: re-enable threads in non-worktree case
  grep: protect packed_git [re-]initialization
  grep: allow submodule functions to run in parallel
  submodule-config: add skip_if_read option to repo_read_gitmodules()
  grep: replace grep_read_mutex by internal obj read lock
  object-store: allow threaded access to object reading
  replace-object: make replace operations thread-safe
  grep: fix racy calls in grep_objects()
  grep: fix race conditions at grep_submodule()
  grep: fix race conditions on userdiff calls
2020-02-14 12:54:20 -08:00
Philippe Blain c56c48dd07 grep: ignore --recurse-submodules if --no-index is given
Since grep learned to recurse into submodules in 0281e487fd
(grep: optionally recurse into submodules, 2016-12-16),
using --recurse-submodules along with --no-index makes Git
die().

This is unfortunate because if submodule.recurse is set in a user's
~/.gitconfig, invoking `git grep --no-index` either inside or outside
a Git repository results in

    fatal: option not supported with --recurse-submodules

Let's allow using these options together, so that setting submodule.recurse
globally does not prevent using `git grep --no-index`.

Using `--recurse-submodules` should not have any effect if `--no-index`
is used inside a repository, as Git will recurse into the checked out
submodule directories just like into regular directories.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Philippe Blain <levraiphilippeblain@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-30 10:15:58 -08:00
Matheus Tavares f1928f04b2 grep: use no. of cores as the default no. of threads
When --threads is not specified, git-grep will use 8 threads by default.
This fixed number may be too many for machines with fewer cores and too
little for machines with more cores. So, instead, use the number of
logical cores available in the machine, which seems to result in the
best overall performance: The following measurements correspond to the
mean elapsed times for 30 git-grep executions in chromium's
repository[1] with a 95% confidence interval (each set of 30 were
performed after 2 warmup runs). Regex 1 is 'abcd[02]' and Regex 2 is
'(static|extern) (int|double) \*'.

      |          Working tree         |           Object Store
------|-------------------------------|--------------------------------
 #ths |  Regex 1      |  Regex 2      |   Regex 1      |   Regex 2
------|---------------|---------------|----------------|---------------
  32  |  2.92s ± 0.01 |  3.72s ± 0.21 |   5.36s ± 0.01 |   6.07s ± 0.01
  16  |  2.84s ± 0.01 |  3.57s ± 0.21 |   5.05s ± 0.01 |   5.71s ± 0.01
>  8  |  2.53s ± 0.00 |  3.24s ± 0.21 |   4.86s ± 0.01 |   5.48s ± 0.01
   4  |  2.43s ± 0.02 |  3.22s ± 0.20 |   5.22s ± 0.02 |   6.03s ± 0.02
   2  |  3.06s ± 0.20 |  4.52s ± 0.01 |   7.52s ± 0.01 |   9.06s ± 0.01
   1  |  6.16s ± 0.01 |  9.25s ± 0.02 |  14.10s ± 0.01 |  17.22s ± 0.01

The above tests were performed in a desktop running Debian 10.0 with
Intel(R) Xeon(R) CPU E3-1230 V2 (4 cores w/ hyper-threading), 32GB of
RAM and a 7200 rpm, SATA 3.1 HDD.

Bellow, the tests were repeated for a machine with SSD: a Manjaro laptop
with Intel(R) i7-7700HQ (4 cores w/ hyper-threading) and 16GB of RAM:

      |          Working tree          |           Object Store
------|--------------------------------|--------------------------------
 #ths |  Regex 1      |  Regex 2       |   Regex 1      |   Regex 2
------|---------------|----------------|----------------|---------------
  32  |  3.29s ± 0.21 |   4.30s ± 0.01 |   6.30s ± 0.01 |   7.30s ± 0.02
  16  |  3.19s ± 0.20 |   4.14s ± 0.02 |   5.91s ± 0.01 |   6.83s ± 0.01
>  8  |  2.90s ± 0.04 |   3.82s ± 0.20 |   5.70s ± 0.02 |   6.53s ± 0.01
   4  |  2.84s ± 0.02 |   3.77s ± 0.20 |   6.19s ± 0.02 |   7.18s ± 0.02
   2  |  3.73s ± 0.21 |   5.57s ± 0.02 |   9.28s ± 0.01 |  11.22s ± 0.01
   1  |  7.48s ± 0.02 |  11.36s ± 0.03 |  17.75s ± 0.01 |  21.87s ± 0.08

[1]: chromium’s repo at commit 03ae96f (“Add filters testing at DSF=2”,
     04-06-2019), after a 'git gc' execution.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-17 13:52:15 -08:00
Matheus Tavares 70a9fef240 grep: move driver pre-load out of critical section
In builtin/grep.c:add_work() we pre-load the userdiff drivers before
adding the grep_source in the todo list. This operation is currently
being performed after acquiring the grep_mutex, but as it's already
thread-safe, we don't need to protect it here. So let's move it out of
the critical section which should avoid thread contention and improve
performance.

Running[1] `git grep --threads=8 abcd[02] HEAD` on chromium's
repository[2], I got the following mean times for 30 executions after 2
warmups:

        Original         |  6.2886s
-------------------------|-----------
 Out of critical section |  5.7852s

[1]: Tests performed on an i7-7700HQ with 16GB of RAM and SSD, running
     Manjaro Linux.
[2]: chromium’s repo at commit 03ae96f (“Add filters testing at DSF=2”,
         04-06-2019), after a 'git gc' execution.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-17 13:52:14 -08:00
Matheus Tavares 1184a95ea2 grep: re-enable threads in non-worktree case
They were disabled at 53b8d93 ("grep: disable threading in non-worktree
case", 12-12-2011), due to observable performance drops (to the point
that using a single thread would be faster than multiple threads). But
now that zlib inflation can be performed in parallel we can regain the
speedup, so let's re-enable threads in non-worktree grep.

Grepping 'abcd[02]' ("Regex 1") and '(static|extern) (int|double) \*'
("Regex 2") at chromium's repository[1] I got:

 Threads |   Regex 1  |  Regex 2
---------|------------|-----------
    1    |  17.2920s  |  20.9624s
    2    |   9.6512s  |  11.3184s
    4    |   6.7723s  |   7.6268s
    8**  |   6.2886s  |   6.9843s

These are all means of 30 executions after 2 warmup runs. All tests were
executed on an i7-7700HQ (quad-core w/ hyper-threading), 16GB of RAM and
SSD, running Manjaro Linux. But to make sure the optimization also
performs well on HDD, the tests were repeated on another machine with an
i5-4210U (dual-core w/ hyper-threading), 8GB of RAM and HDD (SATA III,
5400 rpm), also running Manjaro Linux:

 Threads |   Regex 1  |  Regex 2
---------|------------|-----------
    1    |  18.4035s  |  22.5368s
    2    |  12.5063s  |  14.6409s
    4**  |  10.9136s  |  12.7106s

** Note that in these cases we relied on hyper-threading, and that's
   probably why we don't see a big difference in time.

Unfortunately, multithreaded git-grep might be slow in the non-worktree
case when --textconv is used and there're too many text conversions.
Probably the reason for this is that the object read lock is used to
protect fill_textconv() and therefore there is a mutual exclusion
between textconv execution and object reading. Because both are
time-consuming operations, not being able to perform them in parallel
can cause performance drops. To inform the users about this (and other
threading details), let's also add a "NOTES ON THREADS" section to
Documentation/git-grep.txt.

[1]: chromium’s repo at commit 03ae96f (“Add filters testing at DSF=2”,
     04-06-2019), after a 'git gc' execution.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-17 13:52:14 -08:00
Matheus Tavares 6c307626f1 grep: protect packed_git [re-]initialization
Some fields in struct raw_object_store are lazy initialized by the
thread-unsafe packfile.c:prepare_packed_git(). Although this function is
present in the call stack of git-grep threads, all paths to it are
currently protected by obj_read_lock() (and the main thread usually
indirectly calls it before firing the worker threads, anyway). However,
it's possible that future modifications add new unprotected paths to it,
introducing a race condition. Because errors derived from it wouldn't
happen often, it could be hard to detect. So to prevent future
headaches, let's force eager initialization of packed_git when setting
git-grep up. There'll be a small overhead in the cases where we didn't
really need to prepare packed_git during execution but this shouldn't be
very noticeable.

Also, packed_git may be re-initialized by
packfile.c:reprepare_packed_git(). Again, all paths to it in git-grep
are already protected by obj_read_lock() but it may suffer from the same
problem in the future. So let's also internally protect it with
obj_read_lock() (which is a recursive mutex).

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-17 13:52:14 -08:00
Matheus Tavares c441ea4edc grep: allow submodule functions to run in parallel
Now that object reading operations are internally protected, the
submodule initialization functions at builtin/grep.c:grep_submodule()
are very close to being thread-safe. Let's take a look at each call and
remove from the critical section what we can, for better performance:

- submodule_from_path() and is_submodule_active() cannot be called in
  parallel yet only because they call repo_read_gitmodules() which
  contains, in its call stack, operations that would otherwise be in
  race condition with object reading (for example parse_object() and
  is_promisor_remote()). However, they only call repo_read_gitmodules()
  if it wasn't read before. So let's pre-read it before firing the
  threads and allow these two functions to safely be called in
  parallel.

- repo_submodule_init() is already thread-safe, so remove it from the
  critical section without other necessary changes.

- The repo_read_gitmodules(&subrepo) call at grep_submodule() is safe as
  no other thread is performing object reading operations in the subrepo
  yet. However, threads might be working in the superproject, and this
  function calls add_to_alternates_memory() internally, which is racy
  with object readings in the superproject. So it must be kept
  protected for now. Let's add a "NEEDSWORK" to it, informing why it
  cannot be removed from the critical section yet.

- Finally, add_to_alternates_memory() must be kept protected for the
  same reason as the item above.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-17 13:52:14 -08:00
Matheus Tavares d7992421e1 submodule-config: add skip_if_read option to repo_read_gitmodules()
Currently, submodule-config.c doesn't have an externally accessible
function to read gitmodules only if it wasn't already read. But this
exact behavior is internally implemented by gitmodules_read_check(), to
perform a lazy load. Let's merge this function with
repo_read_gitmodules() adding a 'skip_if_read' which allows both
internal and external callers to access this functionality. This
simplifies a little the code. The added option will also be used in
the following patch.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-17 13:52:14 -08:00
Matheus Tavares 1d1729caeb grep: replace grep_read_mutex by internal obj read lock
git-grep uses 'grep_read_mutex' to protect its calls to object reading
operations. But these have their own internal lock now, which ensures a
better performance (allowing parallel access to more regions). So, let's
remove the former and, instead, activate the latter with
enable_obj_read_lock().

Sections that are currently protected by 'grep_read_mutex' but are not
internally protected by the object reading lock should be surrounded by
obj_read_lock() and obj_read_unlock(). These guarantee mutual exclusion
with object reading operations, keeping the current behavior and
avoiding race conditions. Namely, these places are:

  In grep.c:

  - fill_textconv() at fill_textconv_grep().
  - userdiff_get_textconv() at grep_source_1().

  In builtin/grep.c:

  - parse_object_or_die() and the submodule functions at
    grep_submodule().
  - deref_tag() and gitmodules_config_oid() at grep_objects().

If these functions become thread-safe, in the future, we might remove
the locking and probably get some speedup.

Note that some of the submodule functions will already be thread-safe
(or close to being thread-safe) with the internal object reading lock.
However, as some of them will require additional modifications to be
removed from the critical section, this will be done in its own patch.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-17 13:52:14 -08:00
Matheus Tavares d5b0bac528 grep: fix racy calls in grep_objects()
deref_tag() calls is_promisor_object() and parse_object(), both of which
perform lazy initializations and other thread-unsafe operations. If it
was only called by grep_objects() this wouldn't be a problem as the
latter is only executed by the main thread. However, deref_tag() is also
present in read_object_file()'s call stack. So calling deref_tag() in
grep_objects() without acquiring the grep_read_mutex may incur in a race
condition with object reading operations (such as the ones internally
performed by fill_textconv(), called at fill_textconv_grep()). The same
problem happens with the call to gitmodules_config_oid() which also has
parse_object() in its call stack. Fix that protecting both calls with
the said grep_read_mutex.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-17 13:52:14 -08:00
Matheus Tavares faf123c730 grep: fix race conditions at grep_submodule()
There're currently two function calls in builtin/grep.c:grep_submodule()
which might result in race conditions:

- submodule_from_path(): it has config_with_options() in its call stack
  which, in turn, may have read_object_file() in its own. Therefore,
  calling the first function without acquiring grep_read_mutex may end
  up causing a race condition with other object read operations
  performed by worker threads (for example, at the fill_textconv()
  call in grep.c:fill_textconv_grep()).
- parse_object_or_die(): it falls into the same problem, having
  repo_has_object_file(the_repository, ...) in its call stack. Besides
  that, parse_object(), which is also called by parse_object_or_die(),
  is thread-unsafe and also called by object reading functions.

It's unlikely to really fall into a data race with these operations as
the volume of calls to them is usually very low. But we better protect
ourselves against this possibility, anyway. So, to solve these issues,
move both of these function calls into the critical section of
grep_read_mutex.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-01-17 13:52:14 -08:00
Junio C Hamano e0ff2d4c7e Merge branch 'cb/pcre2-chartables-leakfix'
Leakfix.

* cb/pcre2-chartables-leakfix:
  grep: avoid leak of chartables in PCRE2
  grep: make PCRE2 aware of custom allocator
  grep: make PCRE1 aware of custom allocator
2019-10-23 14:43:11 +09:00
Carlo Marcelo Arenas Belón 513f2b0bbd grep: make PCRE2 aware of custom allocator
94da9193a6 (grep: add support for PCRE v2, 2017-06-01) didn't include
a way to override the system allocator, and so it is incompatible with
custom allocators (e.g. nedmalloc). This problem became obvious when we
tried to plug a memory leak by `free()`ing a data structure allocated by
PCRE2, triggering a segfault in Windows (where we use nedmalloc by
default).

PCRE2 requires the use of a general context to override the allocator
and therefore, there is a lot more code needed than in PCRE1, including
a couple of wrapper functions.

Extend the grep API with a "destructor" that could be called to cleanup
any objects that were created and used globally.

Update `builtin/grep.c` to use that new API, but any other future users
should make sure to have matching `grep_init()`/`grep_destroy()` calls
if they are using the pattern matching functionality.

Move some of the logic that was before done per thread (in the workers)
into an earlier phase to avoid degrading performance, but as the use of
PCRE2 with custom allocators is better understood it is expected more of
its functions will be instructed to use the custom allocator as well as
was done in the original code[1] this work was based on.

[1] https://public-inbox.org/git/3397e6797f872aedd18c6d795f4976e1c579514b.1565005867.git.gitgitgadget@gmail.com/

Reported-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-18 10:33:18 +09:00
René Scharfe fd99c2dd9b grep: use return value of strbuf_detach()
Append the strbuf buffer only after detaching it.  There is no practical
difference here, as the strbuf is not empty and no strbuf_ function is
called between storing the pointer to the still attached buffer and
calling strbuf_detach(), so that pointer is valid, but make sure to
follow the standard sequence anyway for consistency.

Signed-off-by: René Scharfe <l.s.r@web.de>
Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-26 11:32:28 -07:00
Junio C Hamano 307179732d Merge branch 'mt/grep-submodules-working-tree'
"git grep --recurse-submodules" that looks at the working tree
files looked at the contents in the index in submodules, instead of
files in the working tree.

* mt/grep-submodules-working-tree:
  grep: fix worktree case in submodules
2019-08-22 12:34:10 -07:00
Matheus Tavares 6a289d45c0 grep: fix worktree case in submodules
Running git-grep with --recurse-submodules results in a cached grep for
the submodules even when --cached is not used. This makes all
modifications in submodules' tracked files be always ignored when
grepping. Solve that making git-grep respect the cached option when
invoking grep_cache() inside grep_submodule(). Also, add tests to
ensure that the desired behavior is performed.

Reported-by: Daniel Zaoui <jackdanielz@eyomi.org>
Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-07-30 13:29:54 -07:00
Nguyễn Thái Ngọc Duy d3b4705ab8 sha1-file.c: remove the_repo from read_object_with_reference()
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-27 12:45:17 -07:00
Junio C Hamano 7589e63648 Merge branch 'nd/the-index-final'
The assumption to work on the single "in-core index" instance has
been reduced from the library-ish part of the codebase.

* nd/the-index-final:
  cache.h: flip NO_THE_INDEX_COMPATIBILITY_MACROS switch
  read-cache.c: remove the_* from index_has_changes()
  merge-recursive.c: remove implicit dependency on the_repository
  merge-recursive.c: remove implicit dependency on the_index
  sha1-name.c: remove implicit dependency on the_index
  read-cache.c: replace update_index_if_able with repo_&
  read-cache.c: kill read_index()
  checkout: avoid the_index when possible
  repository.c: replace hold_locked_index() with repo_hold_locked_index()
  notes-utils.c: remove the_repository references
  grep: use grep_opt->repo instead of explict repo argument
2019-02-06 22:05:23 -08:00
Junio C Hamano 371820d5f1 Merge branch 'bc/tree-walk-oid'
The code to walk tree objects has been taught that we may be
working with object names that are not computed with SHA-1.

* bc/tree-walk-oid:
  cache: make oidcpy always copy GIT_MAX_RAWSZ bytes
  tree-walk: store object_id in a separate member
  match-trees: use hashcpy to splice trees
  match-trees: compute buffer offset correctly when splicing
  tree-walk: copy object ID before use
2019-01-29 12:47:56 -08:00
Junio C Hamano 5d3635db19 Merge branch 'sb/submodule-recursive-fetch-gets-the-tip'
"git fetch --recurse-submodules" may not fetch the necessary commit
that is bound to the superproject, which is getting corrected.

* sb/submodule-recursive-fetch-gets-the-tip:
  fetch: ensure submodule objects fetched
  submodule.c: fetch in submodules git directory instead of in worktree
  submodule: migrate get_next_submodule to use repository structs
  repository: repo_submodule_init to take a submodule struct
  submodule: store OIDs in changed_submodule_names
  submodule.c: tighten scope of changed_submodule_names struct
  submodule.c: sort changed_submodule_names before searching it
  submodule.c: fix indentation
  sha1-array: provide oid_array_filter
2019-01-29 12:47:54 -08:00
Nguyễn Thái Ngọc Duy f8adbec9fe cache.h: flip NO_THE_INDEX_COMPATIBILITY_MACROS switch
By default, index compat macros are off from now on, because they
could hide the_index dependency.

Only those in builtin can use it.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-24 11:55:06 -08:00
brian m. carlson ea82b2a085 tree-walk: store object_id in a separate member
When parsing a tree, we read the object ID directly out of the tree
buffer. This is normally fine, but such an object ID cannot be used with
oidcpy, which copies GIT_MAX_RAWSZ bytes, because if we are using SHA-1,
there may not be that many bytes to copy.

Instead, store the object ID in a separate struct member. Since we can
no longer efficiently compute the path length, store that information as
well in struct name_entry. Ensure we only copy the object ID into the
new buffer if the path length is nonzero, as some callers will pass us
an empty path with no object ID following it, and we will not want to
read past the end of the buffer.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-15 09:57:41 -08:00
Junio C Hamano d6f05a435f Merge branch 'nd/attr-pathspec-in-tree-walk'
The traversal over tree objects has learned to honor
":(attr:label)" pathspec match, which has been implemented only for
enumerating paths on the filesystem.

* nd/attr-pathspec-in-tree-walk:
  tree-walk: support :(attr) matching
  dir.c: move, rename and export match_attrs()
  pathspec.h: clean up "extern" in function declarations
  tree-walk.c: make tree_entry_interesting() take an index
  tree.c: make read_tree*() take 'struct repository *'
2019-01-14 15:29:28 -08:00
Nguyễn Thái Ngọc Duy 3a7a698e93 sha1-name.c: remove implicit dependency on the_index
This kills the_index dependency in get_oid_with_context() but for
get_oid() and friends, they still assume the_repository (which also
means the_index).

Unfortunately the widespread use of get_oid() will make it hard to
make the conversion now. We probably will add repo_get_oid() at some
point and limit the use of get_oid() in builtin/ instead of forcing
all get_oid() call sites to carry struct repository.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-14 12:13:04 -08:00
Nguyễn Thái Ngọc Duy dba093ddc0 grep: use grep_opt->repo instead of explict repo argument
This command is probably the first one that operates on a repository
other than the_repository, in f9ee2fcdfa (grep: recurse in-process
using 'struct repository' - 2017-08-02). An explicit 'struct
repository *' was added in that commit to pass around the repository
that we're supposed to grep from.

Since 38bbc2ea39 (grep.c: remove implicit dependency on the_index -
2018-09-21). 'struct grep_opt *' carries in itself a repository
parameter for grepping. We should now be able to reuse grep_opt to
hold the submodule repo instead of a separate argument, which is just
room for mistakes.

While at there, use the right reference instead of the_repository and
the_index in this code. I was a bit careless in my attempt to kick
the_repository / the_index out of library code. It's normally safe to
just stick the_repository / the_index in bultin/ code, but it's not
the case for grep.

Reviewed-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-01-14 12:13:04 -08:00
Junio C Hamano 3b2f8a02fa Merge branch 'jk/loose-object-cache'
Code clean-up with optimization for the codepath that checks
(non-)existence of loose objects.

* jk/loose-object-cache:
  odb_load_loose_cache: fix strbuf leak
  fetch-pack: drop custom loose object cache
  sha1-file: use loose object cache for quick existence check
  object-store: provide helpers for loose_objects_cache
  sha1-file: use an object_directory for the main object dir
  handle alternates paths the same as the main object dir
  sha1_file_name(): overwrite buffer instead of appending
  rename "alternate_object_database" to "object_directory"
  submodule--helper: prefer strip_suffix() to ends_with()
  fsck: do not reuse child_process structs
2019-01-04 13:33:32 -08:00
Stefan Beller d5498e0871 repository: repo_submodule_init to take a submodule struct
When constructing a struct repository for a submodule for some revision
of the superproject where the submodule is not contained in the index,
it may not be present in the working tree currently either. In that
situation giving a 'path' argument is not useful. Upgrade the
repo_submodule_init function to take a struct submodule instead.
The submodule struct can be obtained via submodule_from_{path, name} or
an artificial submodule struct can be passed in.

While we are at it, rename the repository struct in the repo_submodule_init
function, which is to be initialized, to a name that is not confused with
the struct submodule as easily. Perform such renames in similar functions
as well.

Also move its documentation into the header file.

Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-12-05 11:42:32 +09:00
Nguyễn Thái Ngọc Duy 67022e0214 tree-walk.c: make tree_entry_interesting() take an index
In order to support :(attr) when matching pathspec on a tree,
tree_entry_interesting() needs to take an index (because
git_check_attr() needs it). This is the preparation step for it. This
also makes it clearer what index we fall back to when looking up
attributes during an unpack-trees operation: the source index.

This also fixes revs->pruning.repo initialization that should have
been done in 2abf350385 (revision.c: remove implicit dependency on
the_index - 2018-09-21). Without it, skip_uninteresting() will
dereference a NULL pointer through this call chain

  get_revision(revs)
  get_revision_internal
  get_revision_1
  try_to_simplify_commit
  rev_compare_tree
  diff_tree_oid(..., &revs->pruning)
  ll_diff_tree_oid
  diff_tree_paths
  ll_diff_tree
  skip_uninteresting

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-19 10:50:33 +09:00
Junio C Hamano ab96f28ba4 Merge branch 'jk/unused-parameter-fixes'
Various functions have been audited for "-Wunused-parameter" warnings
and bugs in them got fixed.

* jk/unused-parameter-fixes:
  midx: double-check large object write loop
  assert NOARG/NONEG behavior of parse-options callbacks
  parse-options: drop OPT_DATE()
  apply: return -1 from option callback instead of calling exit(1)
  cat-file: report an error on multiple --batch options
  tag: mark "--message" option with NONEG
  show-branch: mark --reflog option as NONEG
  format-patch: mark "--no-numbered" option with NONEG
  status: mark --find-renames option with NONEG
  cat-file: mark batch options with NONEG
  pack-objects: mark index-version option as NONEG
  ls-files: mark exclude options as NONEG
  am: handle --no-patch-format option
  apply: mark include/exclude options as NONEG
2018-11-18 18:23:53 +09:00
Junio C Hamano 26b80a841a Merge branch 'nd/pthreads'
The codebase has been cleaned up to reduce "#ifndef NO_PTHREADS".

* nd/pthreads:
  Clean up pthread_create() error handling
  read-cache.c: initialize copy_len to shut up gcc 8
  read-cache.c: reduce branching based on HAVE_THREADS
  read-cache.c: remove #ifdef NO_PTHREADS
  pack-objects: remove #ifdef NO_PTHREADS
  preload-index.c: remove #ifdef NO_PTHREADS
  grep: clean up num_threads handling
  grep: remove #ifdef NO_PTHREADS
  attr.c: remove #ifdef NO_PTHREADS
  name-hash.c: remove #ifdef NO_PTHREADS
  index-pack: remove #ifdef NO_PTHREADS
  send-pack.c: move async's #ifdef NO_PTHREADS back to run-command.c
  run-command.h: include thread-utils.h instead of pthread.h
  thread-utils: macros to unconditionally compile pthreads API
2018-11-18 18:23:52 +09:00
Junio C Hamano abb4824d13 Merge branch 'ao/submodule-wo-gitmodules-checked-out'
The submodule support has been updated to read from the blob at
HEAD:.gitmodules when the .gitmodules file is missing from the
working tree.

* ao/submodule-wo-gitmodules-checked-out:
  t/helper: add test-submodule-nested-repo-config
  submodule: support reading .gitmodules when it's not in the working tree
  submodule: add a helper to check if it is safe to write to .gitmodules
  t7506: clean up .gitmodules properly before setting up new scenario
  submodule: use the 'submodule--helper config' command
  submodule--helper: add a new 'config' subcommand
  t7411: be nicer to future tests and really clean things up
  t7411: merge tests 5 and 6
  submodule: factor out a config_set_in_gitmodules_file_gently function
  submodule: add a print_config_from_gitmodules() helper
2018-11-13 22:37:22 +09:00
Jeff King f0eaf63819 sha1-file: use an object_directory for the main object dir
Our handling of alternate object directories is needlessly different
from the main object directory. As a result, many places in the code
basically look like this:

  do_something(r->objects->objdir);

  for (odb = r->objects->alt_odb_list; odb; odb = odb->next)
        do_something(odb->path);

That gets annoying when do_something() is non-trivial, and we've
resorted to gross hacks like creating fake alternates (see
find_short_object_filename()).

Instead, let's give each raw_object_store a unified list of
object_directory structs. The first will be the main store, and
everything after is an alternate. Very few callers even care about the
distinction, and can just loop over the whole list (and those who care
can just treat the first element differently).

A few observations:

  - we don't need r->objects->objectdir anymore, and can just
    mechanically convert that to r->objects->odb->path

  - object_directory's path field needs to become a real pointer rather
    than a FLEX_ARRAY, in order to fill it with expand_base_dir()

  - we'll call prepare_alt_odb() earlier in many functions (i.e.,
    outside of the loop). This may result in us calling it even when our
    function would be satisfied looking only at the main odb.

    But this doesn't matter in practice. It's not a very expensive
    operation in the first place, and in the majority of cases it will
    be a noop. We call it already (and cache its results) in
    prepare_packed_git(), and we'll generally check packs before loose
    objects. So essentially every program is going to call it
    immediately once per program.

    Arguably we should just prepare_alt_odb() immediately upon setting
    up the repository's object directory, which would save us sprinkling
    calls throughout the code base (and forgetting to do so has been a
    source of subtle bugs in the past). But I've stopped short of that
    here, since there are already a lot of other moving parts in this
    patch.

  - Most call sites just get shorter. The check_and_freshen() functions
    are an exception, because they have entry points to handle local and
    nonlocal directories separately.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-13 14:22:03 +09:00
Jeff King 517fe807d6 assert NOARG/NONEG behavior of parse-options callbacks
When we define a parse-options callback, the flags we put in the option
struct must match what the callback expects. For example, a callback
which does not handle the "unset" parameter should only be used with
PARSE_OPT_NONEG. But since the callback and the option struct are not
defined next to each other, it's easy to get this wrong (as earlier
patches in this series show).

Fortunately, the compiler can help us here: compiling with
-Wunused-parameters can show us which callbacks ignore their "unset"
parameters (and likewise, ones that ignore "arg" expect to be triggered
with PARSE_OPT_NOARG).

But after we've inspected a callback and determined that all of its
callers use the right flags, what do we do next? We'd like to silence
the compiler warning, but do so in a way that will catch any wrong calls
in the future.

We can do that by actually checking those variables and asserting that
they match our expectations. Because this is such a common pattern,
we'll introduce some helper macros. The resulting messages aren't
as descriptive as we could make them, but the file/line information from
BUG() is enough to identify the problem (and anyway, the point is that
these should never be seen).

Each of the annotated callbacks in this patch triggers
-Wunused-parameters, and was manually inspected to make sure all callers
use the correct options (so none of these BUGs should be triggerable).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-06 12:56:29 +09:00
Nguyễn Thái Ngọc Duy fd6263fb73 grep: clean up num_threads handling
When NO_PTHREADS is still used in this file, we have two separate code
paths for thread and no thread support. The latter will always have
num_threads remain zero while the former uses num_threads zero as
"default number of threads".

With recent changes blur the line between thread and no-thread
support, this num_threads handling becomes a bit strange so let's
redefine it like this:

- num_threads == 0 means default number of threads and should become
  positive after all configuration and option parsing is done if
  multithread is supported.

- num_threads <= 1 runs no threads. It does not matter if the platform
  supports threading or not.

- num_threads > 1 will run multiple threads and is invalid if
  HAVE_THREADS is false. pthread API is only used in this case.

PS. a new warning is also added when num_threads is forced back to one
because a thread-incompatible option is specified.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-05 13:42:11 +09:00