- 20 Jul, 2019 6 commits
-
-
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
With commit dedf70ad (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 b0893282 (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.
Patrick Steinhardt committed
-
- 19 Jul, 2019 3 commits
-
-
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed
-
- 18 Jul, 2019 3 commits
-
-
`cvar` is an unhelpful name. Refactor its usage to `configmap` for more clarity.
Patrick Steinhardt committed -
In commit bbf034ab (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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed
-
- 17 Jul, 2019 2 commits
-
-
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.
brian m. carlson committed -
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.
brian m. carlson committed
-
- 12 Jul, 2019 5 commits
-
-
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed
-
- 11 Jul, 2019 17 commits
-
-
In commit 45f24e78 (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.
Patrick Steinhardt committed -
Erik Aigner committed
-
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.
Patrick Steinhardt committed -
Patrick Steinhardt committed
-
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
Error handling in `config_write` is rather convoluted and does not match our current code style. Refactor it to make it easier to understand.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
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`.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed -
Patrick Steinhardt committed
-
- 05 Jul, 2019 2 commits
-
-
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.
Patrick Steinhardt committed -
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.
Patrick Steinhardt committed
-
- 04 Jul, 2019 2 commits
-
-
The function `git_attr_session__init` is currently only initializing setting up the attribute's session key by incrementing the repo-global key by one. Most notably, all other members of the `git_attr_session` struct are not getting initialized at all. So if one is to allocate a session on the stack and then calls `git_attr_session__init`, the session will still not be fully initialized. We have fared just fine with that until now as all users of the function have allocated the session structure as part of bigger structs with `calloc`, and thus its contents have been zero-initialized implicitly already. Fix this by explicitly zeroing out the session to enable allocation of sessions on the stack.
Patrick Steinhardt committed -
Regression introduced in commit 5452e49f on PR #4967. Signed-off-by: Sven Strickroth <email@cs-ware.de>
Sven Strickroth committed
-