We have a number of copies of `UnsafeTransfer` and two copies of
`UnsafeMutableTransferBox` in our code base. Before introducing more of
those, lets centralize to just one using a `package` access modifier.
Add homeDirectory accessor to FileSystem
### Motivation:
Addresses #3381 by adding a `homeDirectory` property to FileSystem,
equivalent to `FileManager.default.homeDirectoryForCurrentUser`.
### Modifications:
- Added `homeDirectory` property to `FileSystemProtocol` and implemented
in `FileSystem`
- Implementation checks `HOME` environment variable first, falls back to
`USERPROFILE` on Windows, or uses `getpwuid_r(3)` on POSIX systems
- Added system call wrappers (`system_getuid`, `libc_getpwuid_r`) with
proper platform guards
- Added `FileSystemError.getpwuid_r()` error helper
### Result:
Users can now access the home directory via `FileSystem.homeDirectory`,
returning a `FilePath` asynchronously. Follows the same pattern as
`currentWorkingDirectory` and `temporaryDirectory`.
Co-authored-by: Cory Benfield <lukasa@apple.com>
Motivation:
The various 'withMumbleContinuation' APIs are supposed to be invoked
synchronously with the caller. This assumption allows a lock to be
acquired before the call and released from the body of the
'withMumbleContinuation' after e.g. storing the continuation. However
this isn't the case and the job may be re-enqueued on the executor
meaning that this is pattern is vulnerable to deadlocks.
Modifications:
- Drop and reacquire the lock in TokenBucket.
- Switch to NIOLockedValueBox
Result:
Lower chance of deadlock
Motivation:
'copyItem' can be used to copy files/directories from a source to a
destination address and fails if the destination already exists. The
parallel version of it can wedge if a directory is being copied and the
directory can't be created at the destination path (for example, if a
file already exists at the destination).
The parallel copy works by feeding tasks (e.g. "copy this item from here
to there") into an async sequence and processing each task in a separate
child task within a task group. When copying directories a new directory
is created at the destination path and then each file within the source
directory is emitted as a separate item to process. Another item is sent
on the async sequence to indicate when the source directory is finished
with which may result in finishing the async sequence.
However, if creating the destination directory fails then that event
isn't sent. This results in the calling code never terminating the async
sequence and causes 'copyItem' to wedge.
Modifications:
- Use non-idempotent directory creation (copy item should fail if the
destination already exists, this was a regression introduced in
7124f096).
- Check whether to continue when a dir can't be created but always emit
the end of dir event
- If terminating when the task group hasn't reached its width limit then
check child tasks for errors
Result:
Parallel copy doesn't wedge
Motivation:
In #3363 we converted `_NIOFileSystem` to `NIOFileSystem` and removed
the (unreleased) overloads for FilePath/NIOFilePath. This change adds
back `_NIOFileSystem` such that it matches the API it had at 2.86.0.
Modifications:
- Add back `_NIOFileSystem` and `_NIOFileSystemFoundationCompat` such
that their API is at 2.86.0
Result:
- `NIOFileSystem` uses `NIOFilePath`
- `_NIOFileSystem` uses `FilePath`
Fabian Fett
Karan Lokchandani
George Barnett
Cory Benfield