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configuration: cvar -> configmap
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`cvar` is an unhelpful name. Refactor its usage to `configmap` for more
clarity.
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Evict cache items more efficiently
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When our object cache is full, we pick eight items (or the whole cache,
if there are fewer) and evict them. For small cache sizes, this is fine,
but when we're dealing with a large number of objects, we can repeatedly
exhaust the cache and spend a large amount of time in git_oidmap_iterate
trying to find items to evict.
Instead, let's assume that if the cache gets full, we have a large
number of objects that we're handling, and be more aggressive about
evicting items. Let's remove one item for every 2048 items, but not less
than 8. This causes us to scale our evictions in proportion to the size
of the cache and significantly reduces the time we spend in
git_oidmap_iterate.
Before this change, a full pack of all the non-blob objects in the Linux
repository took in excess of 30 minutes and spent 62.3% of total runtime
in odb_read_1 and its children, and 44.3% of the time in
git_oidmap_iterate. With this change, the same operation now takes 14
minutes and 44 seconds, and odb_read_1 accounts for only 35.9% of total
time, whereas git_oidmap_iterate consists of 6.2%.
Note that we do spend a little more time inflating objects and a decent
amount more time in memcmp. However, overall, the time taken is
significantly improved, and time in pack building is now dominated by
git_delta_create_from_index (33.7%), which is what we would expect.
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clar: fix suite count
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With the introduction of data variants for suites, we started
undercounting the number of suites as we didn't account for those that
were executed twice. This was then adjusted to count the number of
initializers instead, but this fails to account for suites without any
initializers at all.
Fix the suite count by counting either the number of initializers or, if
there is no initializer, count it as a single suite, only.
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Ignore VS2017 specific files and folders
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Signed-off-by: Sven Strickroth <email@cs-ware.de>
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gitattributes: ignore macros defined in subdirectories
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Right now, we are unconditionally applying all macros found in a
gitatttributes file. But quoting gitattributes(5):
Custom macro attributes can be defined only in top-level
gitattributes files ($GIT_DIR/info/attributes, the .gitattributes
file at the top level of the working tree, or the global or
system-wide gitattributes files), not in .gitattributes files in
working tree subdirectories. The built-in macro attribute "binary"
is equivalent to:
So gitattribute files in subdirectories of the working tree may
explicitly _not_ contain macro definitions, but we do not currently
enforce this limitation.
This patch introduces a new parameter to the gitattributes parser that
tells whether macros are allowed in the current file or not. If set to
`false`, we will still parse macros, but silently ignore them instead of
adding them to the list of defined macros. Update all callers to
correctly determine whether the to-be-parsed file may contain macros or
not. Most importantly, when walking up the directory hierarchy, we will
only set it to `true` once it reaches the root directory of the repo
itself.
Add a test that verifies that we are indeed not applying macros from
subdirectories. Previous to these changes, the test would've failed.
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The gitattributes code is one of our oldest and most-untouched codebases
in libgit2, and as such its code style doesn't quite match our current
best practices. Refactor the function `git_attr_file__parse_buffer` to
better match them.
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The gitattributes code is one of our oldest and most-untouched codebases
in libgit2, and as such its code style doesn't quite match our current
best practices. Refactor the function `git_attr_file__lookup_standalone`
to better match them.
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A macro without any assignments is considered an invalid macro by the
attributes cache and is thus not getting added to the macro map at all.
But as `git_attr_cache__insert_macro` returns success with neither
free'ing nor adopting the macro into its map, this will cause a memory
leak.
Fix this by freeing the macro in the function if it's not going to be
added. This is perfectly fine to do, as callers assume that the
attrcache will have the macro adopted on success anyway.
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The function `git_attr_cache__insert_macro` is responsible for adopting
macros in the per-repo macro cache. When adding a macro that replaces an
already existing macro (e.g. because of re-parsing gitattributes files),
then we do not free the previous macro and thus cause a memory leak.
Fix this leak by first checking if the cache already has a macro defined
with the same name. If so, free it before replacing the cache entry with
the new instance.
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Add some tests to ensure that the `git_attr_add_macro` function works as
expected.
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Implement some tests that verify that we are correctly updating
gitattributes when rewriting or unlinking the corresponding files.
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As macros are a specific functionality in the gitattributes code, it
makes sense to extract them into their own test suite, too. This makes
finding macro-related tests easier.
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clar: correctly account for "data" suites when counting
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Failing to do that makes clar miss the last of the suites, as all
duplicated "data" would have not been accounted for.
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Allocate memory more efficiently when packing objects
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The packbuilder code allocates memory in chunks. When it needs to
allocate, it tries to add 1024 to the number of objects and multiply by
3/2. However, it actually multiplies by 1 instead, since it performs an
integral division in the expression "3 / 2" and only then multiplies by
the increased number of objects.
The current behavior causes the code to waste massive amounts of time
copying memory when it reallocates, causing inserting all non-blob
objects in the Linux repository into a new pack to take some
indeterminate time greater than 5 minutes instead of 52 seconds.
Correct this error by first dividing by two, and only then multiplying
by 3. We still check for overflow for the multiplication, which is the
only part that can overflow. This appears to be the only place in the
code base which has this problem.
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fileops: fix creation of directory in filesystem root
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In commit 45f24e787 (git_repository_init: stop traversing at
windows root, 2019-04-12), we have fixed `git_futils_mkdir` to
correctly handle the case where we create a directory in
Windows-style filesystem roots like "C:\repo".
The problem here is an off-by-one: previously, to that commit,
we've been checking wether the parent directory's length is equal
to the root directory's length incremented by one. When we call
the function with "/example", then the parent directory's length
("/") is 1, but the root directory offset is 0 as the path is
directly rooted without a drive prefix. This resulted in `1 == 0 +
1`, which was true. With the change, we've stopped incrementing
the root directory length, and thus now compare `1 <= 0`, which
is false.
The previous way of doing it was kind of finicky any non-obvious,
which is also why the error was introduced. So instead of just
re-adding the increment, let's explicitly add a condition that
aborts finding the parent if the current parent path is "/".
Making this change causes Azure Pipelines to fail the testcase
repo::init::nonexistent_paths on Unix-based systems. This is because we
have just fixed creating directories in the filesystem root, which
previously didn't work. As Docker-based tests are running as root user,
we are thus able to create the non-existing path and will now succeed to
create the repository that was expected to actually fail.
Let's split this up into three different tests:
- A test to verify that we do not create repos in a non-existing parent
directoy if the flag `GIT_REPOSITORY_INIT_MKPATH` is not set.
- A test to verify that we fail if the root directory does not exist. As
there is a common root directory on Unix-based systems that always
exist, we can only test for this on Windows-based systems.
- A test to verify that we fail if trying to create a repository in an
unwriteable parent directory. We can only test this if not running
tests as root user, as CAP_DAC_OVERRIDE will cause us to ignore
permissions when creating files.
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win32: fix fuzzers and have CI build them
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In order to guarantee that our fuzzers build just fine on the Windows
platform, let's enable building fuzzers on all Powershell-based builds.
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There's multiple headers included in our fuzzers that aren't required at
all. Furthermore, some of them are not available on Win32, causing
builds to fail. Remove them to fix this.
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The `snprintf` function does not exist on Win32, it only has
`_snprintf_s` available. Let's just avoid any cross-platform hassle and
use our own `git_buf` functionality instead.
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Use `p_unlink` instead of `unlink` to remove the generated packfiles in
our packfile fuzzer. Like this, we do not have to worry about using
proper includes that are known on all platforms, especially Win32.
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The `printf` formatters in our standalone fuzzing driver are currently
using the "%m" specifier, which is a GNU extension that prints the error
message for the error code in `errno`. As we're using libgit2 functions
in both cases anyway, let's just use `git_error_last` instead to make
this valid on all platforms.
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The `mkdtemp` function is not available on Windows, so our download_refs
fuzzer will fail to compile on Windows. Provide an alternative
implementation to fix it.
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Config parser separation
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Right now, all configuration file backends are expected to
directly mess with the configuration parser's internals in order
to set it up. Let's avoid doing that by implementing both a
`git_config_parser_init` and `git_config_parser_dispose` function
to clearly define the interface between configuration backends
and the parser.
Ideally, we would make the `git_config_parser` structure
definition private to its implementation. But as that would
require an additional memory allocation that was not required
before we just live with it being visible to others.
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Error handling in `config_write` is rather convoluted and does
not match our current code style. Refactor it to make it easier
to understand.
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With the previous commits, we have finally separated the config
parsing logic from the specific configuration file backend. Due
to that, we can now move the `git_config_file` structure into the
config file backend's implementation so that no other code may
accidentally start using it again. Furthermore, we rename the
structure to `diskfile` to make it obvious that it is internal,
only, and to unify it with naming scheme of the other diskfile
structures.
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The config parser code needs to keep track of the current parsed
file's name so that we are able to provide proper error messages
to the user. Right now, we do that by storing a `git_config_file`
in the parser structure, but as that is a specific backend and
the parser aims to be generic, it is a layering violation.
Switch over to use a simple string to fix that.
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The config file code needs to keep track of the actual
`git_config_file` structure, as it not only contains the path
of the current configuration file, but it also keeps tracks of
all includes of that file. Right now, we keep track of that
structure via the `git_config_parser`, but as that's supposed to
be a backend generic implementation of configuration parsing it's
a layering violation to have it in there.
Switch over the config file backend to use its own config file
structure that's embedded in the backend parse data. This allows
us to switch over the generic config parser to avoid using the
`git_config_file` structure.
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By convention, parameters that get passed to callbacks are
usually named `payload` in our codebase. Rename the `data`
parameters in the configuration parser callbacks to `payload` to
avoid confusion.
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config_file: implement stat cache to avoid repeated rehashing
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When we rewrite the configuration file due to any of its values
being modified, we call `config_refresh` to update the in-memory
representation of our config file backend. This is needlessly
wasteful though, as `config_refresh` will always open the on-disk
representation to reads the file contents while we already know
the complete file contents at this point in time as we have just
written it to disk.
Implement a new function `config_refresh_from_buffer` that will
refresh the backend's config entries from a buffer instead of
from the config file itself. Note that this will thus _not_
update the backend's timestamp, which will cause us to re-read
the buffer when performing a read operation on it. But this is
still an improvement as we now lazily re-read the contents, and
most importantly we will avoid constantly re-reading the contents
if we perform multiple write operations.
The following strace demonstrates this if we're re-writing a key
multiple times. It uses our config example with `config_set`
changed to update the file 10 times with different keys:
$ strace lg2 config x.x z |& grep '^open.*config'
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/home/pks/.config/git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
And now with the optimization of `config_refresh_from_buffer`:
$ strace lg2 config x.x z |& grep '^open.*config'
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
open("/home/pks/.config/git/config", O_RDONLY|O_CLOEXEC) = 3
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
open("/tmp/repo/.git/config.lock", O_WRONLY|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 3
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 4
As can be seen, this is quite a lot of `open` calls less.
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Updating a config file backend's config entries is a bit more
involved, as it requires clearing of the old config entries as
well as handling locking correctly. As we will need this
functionality in a future patch to refresh config entries from a
buffer, let's extract this into its own function
`config_set_entries`.
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The `config_read` function currently performs both reading the
on-disk config file as well as parsing the retrieved buffer
contents. To optimize how we refresh our config entries from an
in-memory buffer, we need to be able to directly parse buffers,
though, without involving any on-disk files at all.
Extract a new function `config_read_buffer` that sets up the
parsing logic and then parses config entries from a buffer, only.
Have `config_read` use it to avoid duplicated logic.
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We are quite lazy in how we refresh our config file backend when
updating any of its keys: instead of just updating our in-memory
representation of the keys, we just discard the old set of keys
and then re-read the config file contents from disk. This refresh
currently happens separately at every callsite of `config_write`,
but it is clear that we _always_ want to refresh if we have
written the config file to disk. If we didn't, then we'd run
around with an outdated config file backend that does not
represent what we have on disk.
By moving the refresh into `config_write`, we are also able to
optimize the case where the config file is currently locked.
Before, we would've tried to re-read the file even if we have
only updated its cached contents without touching the on-disk
file. Thus we'd have unnecessarily stat'd the file, even though
we know that it shouldn't have been modified in the meantime due
to its lock.
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To decide whether a config file has changed, we always hash its
complete contents. This is unnecessarily expensive, as
well-behaved filesystems will always update stat information for
files which have changed. So before computing the hash, we should
first check whether the stat info has actually changed for either
the configuration file or any of its includes. This avoids having
to re-read the configuration file and its includes every time
when we check whether it's been modified.
Tracing the for-each-ref example previous to this commit, one can
see that we repeatedly re-open both the repo configuration as
well as the global configuration:
$ strace lg2 for-each-ref |& grep config
access("/home/pks/.gitconfig", F_OK) = -1 ENOENT (No such file or directory)
access("/home/pks/.config/git/config", F_OK) = 0
access("/etc/gitconfig", F_OK) = -1 ENOENT (No such file or directory)
stat("/tmp/repo/.git/config", {st_mode=S_IFREG|0644, st_size=92, ...}) = 0
access("/tmp/repo/.git/config", F_OK) = 0
stat("/tmp/repo/.git/config", {st_mode=S_IFREG|0644, st_size=92, ...}) = 0
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
stat("/home/pks/.gitconfig", 0x7ffd15c05290) = -1 ENOENT (No such file or directory)
access("/home/pks/.gitconfig", F_OK) = -1 ENOENT (No such file or directory)
stat("/home/pks/.config/git/config", {st_mode=S_IFREG|0644, st_size=1154, ...}) = 0
access("/home/pks/.config/git/config", F_OK) = 0
stat("/home/pks/.config/git/config", {st_mode=S_IFREG|0644, st_size=1154, ...}) = 0
open("/home/pks/.config/git/config", O_RDONLY|O_CLOEXEC) = 3
stat("/tmp/repo/.git/config", {st_mode=S_IFREG|0644, st_size=92, ...}) = 0
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
stat("/home/pks/.gitconfig", 0x7ffd15c051f0) = -1 ENOENT (No such file or directory)
stat("/home/pks/.config/git/config", {st_mode=S_IFREG|0644, st_size=1154, ...}) = 0
open("/home/pks/.config/git/config", O_RDONLY|O_CLOEXEC) = 3
stat("/tmp/repo/.git/config", {st_mode=S_IFREG|0644, st_size=92, ...}) = 0
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
stat("/home/pks/.gitconfig", 0x7ffd15c05090) = -1 ENOENT (No such file or directory)
stat("/home/pks/.config/git/config", {st_mode=S_IFREG|0644, st_size=1154, ...}) = 0
open("/home/pks/.config/git/config", O_RDONLY|O_CLOEXEC) = 3
stat("/tmp/repo/.git/config", {st_mode=S_IFREG|0644, st_size=92, ...}) = 0
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
stat("/home/pks/.gitconfig", 0x7ffd15c05090) = -1 ENOENT (No such file or directory)
stat("/home/pks/.config/git/config", {st_mode=S_IFREG|0644, st_size=1154, ...}) = 0
open("/home/pks/.config/git/config", O_RDONLY|O_CLOEXEC) = 3
stat("/tmp/repo/.git/config", {st_mode=S_IFREG|0644, st_size=92, ...}) = 0
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
stat("/home/pks/.gitconfig", 0x7ffd15c05090) = -1 ENOENT (No such file or directory)
stat("/home/pks/.config/git/config", {st_mode=S_IFREG|0644, st_size=1154, ...}) = 0
open("/home/pks/.config/git/config", O_RDONLY|O_CLOEXEC) = 3
With the change, we only do stats for those files and open them a
single time, only:
$ strace lg2 for-each-ref |& grep config
access("/home/pks/.gitconfig", F_OK) = -1 ENOENT (No such file or directory)
access("/home/pks/.config/git/config", F_OK) = 0
access("/etc/gitconfig", F_OK) = -1 ENOENT (No such file or directory)
stat("/tmp/repo/.git/config", {st_mode=S_IFREG|0644, st_size=92, ...}) = 0
access("/tmp/repo/.git/config", F_OK) = 0
stat("/tmp/repo/.git/config", {st_mode=S_IFREG|0644, st_size=92, ...}) = 0
stat("/tmp/repo/.git/config", {st_mode=S_IFREG|0644, st_size=92, ...}) = 0
open("/tmp/repo/.git/config", O_RDONLY|O_CLOEXEC) = 3
stat("/home/pks/.gitconfig", 0x7ffe70540d20) = -1 ENOENT (No such file or directory)
access("/home/pks/.gitconfig", F_OK) = -1 ENOENT (No such file or directory)
stat("/home/pks/.config/git/config", {st_mode=S_IFREG|0644, st_size=1154, ...}) = 0
access("/home/pks/.config/git/config", F_OK) = 0
stat("/home/pks/.config/git/config", {st_mode=S_IFREG|0644, st_size=1154, ...}) = 0
stat("/home/pks/.config/git/config", {st_mode=S_IFREG|0644, st_size=1154, ...}) = 0
open("/home/pks/.config/git/config", O_RDONLY|O_CLOEXEC) = 3
stat("/tmp/repo/.git/config", {st_mode=S_IFREG|0644, st_size=92, ...}) = 0
stat("/home/pks/.gitconfig", 0x7ffe70540ca0) = -1 ENOENT (No such file or directory)
stat("/home/pks/.gitconfig", 0x7ffe70540c80) = -1 ENOENT (No such file or directory)
stat("/home/pks/.config/git/config", {st_mode=S_IFREG|0644, st_size=1154, ...}) = 0
stat("/tmp/repo/.git/config", {st_mode=S_IFREG|0644, st_size=92, ...}) = 0
stat("/home/pks/.gitconfig", 0x7ffe70540b40) = -1 ENOENT (No such file or directory)
stat("/home/pks/.gitconfig", 0x7ffe70540b20) = -1 ENOENT (No such file or directory)
stat("/home/pks/.config/git/config", {st_mode=S_IFREG|0644, st_size=1154, ...}) = 0
stat("/tmp/repo/.git/config", {st_mode=S_IFREG|0644, st_size=92, ...}) = 0
stat("/home/pks/.gitconfig", 0x7ffe70540b40) = -1 ENOENT (No such file or directory)
stat("/home/pks/.gitconfig", 0x7ffe70540b20) = -1 ENOENT (No such file or directory)
stat("/home/pks/.config/git/config", {st_mode=S_IFREG|0644, st_size=1154, ...}) = 0
stat("/tmp/repo/.git/config", {st_mode=S_IFREG|0644, st_size=92, ...}) = 0
stat("/home/pks/.gitconfig", 0x7ffe70540b40) = -1 ENOENT (No such file or directory)
stat("/home/pks/.gitconfig", 0x7ffe70540b20) = -1 ENOENT (No such file or directory)
stat("/home/pks/.config/git/config", {st_mode=S_IFREG|0644, st_size=1154, ...}) = 0
The following benchmark has been performed with and without the
stat cache in a best-of-ten run:
```
int lg2_repro(git_repository *repo, int argc, char **argv)
{
git_config *cfg;
int32_t dummy;
int i;
UNUSED(argc);
UNUSED(argv);
check_lg2(git_repository_config(&cfg, repo),
"Could not obtain config", NULL);
for (i = 1; i < 100000; ++i)
git_config_get_int32(&dummy, cfg, "foo.bar");
git_config_free(cfg);
return 0;
}
```
Without stat cache:
$ time lg2 repro
real 0m1.528s
user 0m0.568s
sys 0m0.944s
With stat cache:
$ time lg2 repro
real 0m0.526s
user 0m0.268s
sys 0m0.258s
This benchmark shows a nearly three-fold performance improvement.
This change requires that we check our configuration stress tests
as we're now in fact becoming more racy. If somebody is writing a
configuration file at nearly the same time (there is a window of
100ns on Windows-based systems), then it might be that we realize
that this file has actually changed and thus may not re-read it.
This will only happen if either an external process is rewriting
the configuration file or if the same process has multiple
`git_config` structures pointing to the same time, where one of
both is being used to write and the other one is used to read
values.
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Implement a new example that resembles git-config(1). Right now,
this example can both read and set configuration keys, only.
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Depending on the platform and on build options, we may or may not
build libgit2 with support for nanoseconds when using `stat`
calls. It's currently unclear though whether sub-second stat
information is used at all.
Add feature info for this to tell at configure time whether it's
being used or not.
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ci: build with ENABLE_WERROR on Windows
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The function `git_win32__stack__set_aux_cb` expects the second parameter
to be a function callback of type `git_win32__stack__aux_cb_lookup`,
which expects a `size_t` parameter. In our test suite
trace::windows::stacktrace, we declare the callback with `unsigned int`
as parameter, though, causing a compiler warning.
Correct the parameter type to silence the warning.
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In both `git_win32__stack_format` and `git_win32__stack`, we handle
buffer lengths via an integer variable. As we only ever pass buffer
sizes to it, this should be a `size_t` though to avoid loss of
precision. As we also use it to compare with other `size_t` variables,
this also silences signed/unsigned comparison warnings.
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