Disambiguate error values: return `GIT_ENOTFOUND` when the item cannot
exist in the repository (perhaps because the repository is inmemory or
otherwise not backed by a filesystem), return `-1` when there is a hard
failure.
Initially, the setting has been solely used to enable the use of
`fsync()` when creating objects. Since then, the use has been extended
to also cover references and index files. As the option is not yet part
of any release, we can still correct this by renaming the option to
something more sensible, indicating not only correlation to objects.
This commit renames the option to `GIT_OPT_ENABLE_FSYNC_GITDIR`. We also
move the variable from the object to repository source code.
The current signature of `git_worktree_prune` accepts a flags field to
alter its behavior. This is not as flexible as we'd like it to be when
we want to enable passing additional options in the future. As the
function has not been part of any release yet, we are still free to
alter its current signature. This commit does so by using our usual
pattern of an options structure, which is easily extendable without
breaking the API.
When creating a new worktree, we do have a potential race with us
creating the worktree and another process trying to delete the same
worktree as it is being created. As such, the upstream git project has
introduced a flag `git worktree add --locked`, which will cause the
newly created worktree to be locked immediately after its creation. This
mitigates the race condition.
We want to be able to mirror the same behavior. As such, a new flag
`locked` is added to the options structure of `git_worktree_add` which
allows the user to enable this behavior.
The `git_worktree_add` function currently accepts only a path and name
for the new work tree. As we may want to expand these parameters in
future versions without adding additional parameters to the function for
every option, this commit introduces our typical pattern of an options
struct. Right now, this structure is still empty, which will change with
the next commit.
Verifying hashsums of objects we are reading from the ODB may be costly
as we have to perform an additional hashsum calculation on the object.
Especially when reading large objects, the penalty can be as high as
35%, as can be seen when executing the equivalent of `git cat-file` with
and without verification enabled. To mitigate for this, we add a global
option for libgit2 which enables the developer to turn off the
verification, e.g. when he can be reasonably sure that the objects on
disk won't be corrupted.
The upstream git.git project verifies objects when looking them up from
disk. This avoids scenarios where objects have somehow become corrupt on
disk, e.g. due to hardware failures or bit flips. While our mantra is
usually to follow upstream behavior, we do not do so in this case, as we
never check hashes of objects we have just read from disk.
To fix this, we create a new error class `GIT_EMISMATCH` which denotes
that we have looked up an object with a hashsum mismatch. `odb_read_1`
will then, after having read the object from its backend, hash the
object and compare the resulting hash to the expected hash. If hashes do
not match, it will return an error.
This obviously introduces another computation of checksums and could
potentially impact performance. Note though that we usually perform I/O
operations directly before doing this computation, and as such the
actual overhead should be drowned out by I/O. Running our test suite
seems to confirm this guess. On a Linux system with best-of-five
timings, we had 21.592s with the check enabled and 21.590s with the
ckeck disabled. Note though that our test suite mostly contains very
small blobs only. It is expected that repositories with bigger blobs may
notice an increased hit by this check.
In addition to a new test, we also had to change the
odb::backend::nonrefreshing test suite, which now triggers a hashsum
mismatch when looking up the commit "deadbeef...". This is expected, as
the fake backend allocated inside of the test will return an empty
object for the OID "deadbeef...", which will obviously not hash back to
"deadbeef..." again. We can simply adjust the hash to equal the hash of
the empty object here to fix this test.
As with the callbacks, third-party implementations of smart subtransports cannot
reach into the opaque struct and thus cannot know what options the user set.
Add a getter for these options to copy the proxy options into something external
implementors can use.
This can prevent FILE_SHARED_VIOLATIONS when used in tools such as TortoiseGit TGitCache and FILE_SHARE_DELETE, because files can be opened w/o being locked any more.
Signed-off-by: Sven Strickroth <email@cs-ware.de>
Provide a macro that will allow us to run a function with posix-like
return values multiple times in a retry loop, with an optional cleanup
function called between invocations.
While we already provide functionality to look up a worktree from a
repository, we cannot do so the other way round. That is given a
repository, we want to look up its worktree if it actually exists.
Getting the worktree of a repository is useful when we want to get
certain meta information like the parent's location, getting the locked
status, etc.
The functions `git_commit_header_field` and
`git_commit_extract_signature` both receive buffers used to hand back
the results to the user. While these functions called `git_buf_sanitize`
on these buffers, this is not the right thing to do, as it will simply
initialize or zero-terminate passed buffers. As we want to overwrite
contents, we instead have to call `git_buf_clear` to completely reset
them.
Implement a new function that is able to determine if a branch is
checked out in any repository connected to the current
repository. In particular, this is required to check if for a
given repository and branch, there exists any working tree
connected to that repository that is referencing this branch.
Implement `git_repository_head_for_worktree` and
`git_repository_head_detached_for_worktree` for directly accessing a
worktree's HEAD without opening it as a `git_repository` first.
Implement the `git_worktree_prune` function. This function can be
used to delete working trees from a repository. According to the
flags passed to it, it can either delete the working tree's
gitdir only or both gitdir and the working directory.
Working trees support locking by creating a file `locked` inside
the tree's gitdir with an optional reason inside. Support this
feature by adding functions to get and set the locking status.
