| Commit message (Collapse) | Author | Age | Files | Lines |
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In #5118 we remove the double-underscore to make it a normally-named public
function. However, this is not an interesting function outside of the library
and it takes up a name for something that could be more useful.
Remove the single-underscore version as we have not done any releases with it.
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When creating a new iterator for a config file backend, then we should
always make sure that we're up to date by calling `config_refresh`.
Otherwise, we might not notice when another process has modified the
configuration file and thus will represent outdated values.
Add two tests to config::stress that verify that we get up-to-date
values when reading configuration entries via `git_config_iterator`.
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If calling `config_refresh` on a read-only configuration file backend,
then we will segfault when comparing the timestamp of the file due to
`path` being uninitialized. As a read-only snapshot should not be
refreshed anyway and stay consistent, we can simply return early when
calling `config_refresh` on a read-only snapshot.
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On most platforms it's fine to create symlinks to nonexisting files. Not
so on Windows, where the type of a symlink (file or directory) needs to
be set at creation time. So depending on whether the target file exists
or not, we may end up with different symlink types. This creates a
problem when performing checkouts, where we simply iterate over all blobs
that need to be updated without treating symlinks any special. If the
target file of the symlink is going to be checked out after the symlink
itself, then the symlink will be created as directory symlink and not as
file symlink.
Fix the issue by iterating over blobs twice: once to perform postponed
deletions and updates to non-symlink blobs, and once to perform updates
to symlink blobs.
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When creating a symlink in Windows, one needs to tell Windows whether
the symlink should be a file or directory symlink. To determine which
flag to pass, we call `GetFileAttributesW` on the target file to see
whether it is a directory and then pass the flag accordingly. The
problem though is if create a symlink with a relative target path, then
we will check that relative path while not necessarily being inside of
the working directory where the symlink is to be created. Thus, getting
its attributes will either fail or return attributes of the wrong
target.
Fix this by resolving the target path relative to the directory in which
the symlink is to be created.
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When deleting a symlink on Windows, then the way to delete it depends on
whether it is a directory symlink or a file symlink. In the first case,
we need to use `DeleteFile`, in the second `RemoveDirectory`. Right now,
`p_unlink` will only ever try to use `DeleteFile`, though, and thus fail
to remove directory symlinks. This mismatches how unlink(3P) is expected
to behave, though, as it shall remove any symlink disregarding whether
it is a file or directory symlink.
In order to correctly unlink a symlink, we thus need to check what kind
of file this is. If we were to first query file attributes of every file
upon calling `p_unlink`, then this would penalize the common case
though. Instead, we can try to first delete the file with `DeleteFile`
and only if the error returned is `ERROR_ACCESS_DENIED` will we query
file attributes and determine whether it is a directory symlink to use
`RemoveDirectory` instead.
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When initializing a repository, we need to check whether its working
directory supports symlinks to correctly set the initial value of the
"core.symlinks" config variable. The code to check the filesystem is
reusable in other parts of our codebase, like for example in our tests
to determine whether certain tests can be expected to succeed or not.
Extract the code into a new function `git_path_supports_symlinks` to
avoid duplicate implementations. Remove a duplicate implementation in
the repo test helper code.
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Our file utils functions all have a "futils" prefix, e.g.
`git_futils_touch`. One would thus naturally guess that their
definitions and implementation would live in files "futils.h" and
"futils.c", respectively, but in fact they live in "fileops.h".
Rename the files to match expectations.
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With commit dedf70ad2 (patch_parse: do not depend on parsed buffer's
lifetime, 2019-07-05), all lines of the patch are allocated with
`strdup` to make lifetime of the parsed patch independent of the buffer
that is currently being parsed. In patch b08932824 (patch_parse: ensure
valid patch output with EOFNL, 2019-07-11), we introduced another
code location where we add lines to the parsed patch. But as that one
was implemented via a separate pull request, it wasn't converted to use
`strdup`, as well. As a consequence, we generate a segfault when trying
to deallocate the potentially static buffer that's now in some of the
lines.
Use `git__strdup` to fix the issue.
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ignore: fix determining whether a shorter pattern negates another
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When computing whether we need to store a negative pattern, we iterate
through all previously known patterns and check whether the negative
pattern undoes any of the previous ones. In doing so we call `wildmatch`
and check it's return for any negative error values. If there was a
negative return, we will abort and bubble up that error to the caller.
In fact, this check for negative values stems from the time where we
still used `fnmatch` instead of `wildmatch`. For `fnmatch`, negative
values indicate a "real" error, while for `wildmatch` a negative value
may be returned if the matching was prematurely aborted. A premature
abort may for example also happen if the pattern matches a prefix of the
haystack if the pattern is shorter. Returning an error in that case is
the wrong thing to do.
Fix the code to compare for equality with `WM_MATCH`, only. Negative
values returned by `wildmatch` are perfectly fine and thus should be
ignored. Add a test that verifies we do not see the error.
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patch_parse: handle missing newline indicator in old file
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When either the old or new file contents have no newline at the end of
the file, then git-diff(1) will print out a "\ No newline at end of
file" indicator. While we do correctly handle this in the case where the
new file has this indcator, we fail to parse patches where the old file
is missing a newline at EOF.
Fix this bug by handling and missing newline indicators in the old file.
Add tests to verify that we can parse such files.
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The patch ID is supposed to be mostly context-insignificant and
thus only includes added or deleted lines. As such, we shouldn't honor
end-of-file-without-newline markers in diffs.
Ignore such lines to fix how we compute the patch ID for such diffs.
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patch_parse: do not depend on parsed buffer's lifetime
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When parsing a patch from a buffer, we let the patch lines point into
the original buffer. While this is efficient use of resources, this also
ties the lifetime of the parsed patch to the parsed buffer. As this
behaviour is not documented anywhere in our API it is very surprising to
its users.
Untie the lifetime by duplicating the lines into the parsed patch. Add a
test that verifies that lifetimes are indeed independent of each other.
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sha1: fix compilation of WinHTTP backend
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In commit bbf034ab9 (hash: move `git_hash_prov` into Win32 backend,
2019-02-22), the `git_hash_prov`'s structure name has been removed in
favour of its typedef'ed name. But as we have no CI that compiles with
the WinHTTPS hashing backend right now, it wasn't noticed that the
implementation that uses this struct wasn't changed correctly.
Fix the struct type to make it compile again.
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repository: do not initialize HEAD if it's provided by templates
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When using templates to initialize a git repository, then git-init(1)
will copy over all contents of the template directory. These will be
preferred over the default ones created by git-init(1). While we mostly
do the same, there is the exception of "HEAD". While we do copy over the
template's HEAD file, afterwards we'll immediately re-initialize its
contents with either the default "ref: refs/origin/master" or the init
option's `initial_head` field.
Let's fix the inconsistency with upstream git-init(1) by not overwriting
the template HEAD, but only if the user hasn't set `opts.initial_head`.
If the `initial_head` field has been supplied, we should use that
indifferent from whether the template contained a HEAD file or not. Add
tests to verify we correctly use the template directory's HEAD file and
that `initial_head` overrides the template.
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Update `git_repository_init_ext` to use our typical style of error
handling. The function had multiple statements which didn't `goto out`
immediately but instead deferred it to later calls combined with `if`
statements.
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The error handling in `git_repository_create_head` completely swallows
all error codes. While probably not too much of a problem, this also
violates our usual coding style.
Refactor the code to use a local `error` variable with the typical `goto
out` statements.
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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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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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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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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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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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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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ci: build with ENABLE_WERROR on Windows
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