FileDescriptor: Add resize(to newSize:) and fileSize() APIs #82
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Signed-off-by: Si Beaumont <beaumont@apple.com>
| @inline(__always) | ||
| internal func ftruncate( | ||
| _ fd: Int32, _ length: off_t | ||
| ) -> Int32 { | ||
| _chsize(fd, numericCast(length)) | ||
| } |
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Full disclosure: I have not tested the Windows path. AFAICT there isn't a Windows CI pipeline?
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I believe it's best to surround the addition of resize with #if !os(Windows).
Generally, I don't think it's a good idea to try to shoehorn Windows support into POSIX code paths here, or anywhere else in this code base. Swift System is not intended to provide a portable API layer, and the Windows SDK is different enough that it deserves its own, standalone, implementations.
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OK, apologies for that, I was just following the pattern I saw with the existing WindowsSyscallAdapters. I added some fixups which move this API to only non-Windows platforms:
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@swift-ci please test |
Signed-off-by: Si Beaumont <beaumont@apple.com>
|
@swift-ci please test |
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@lorentey can you take an initial look? |
Sources/System/FileHelpers.swift
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| ) throws -> Int64 { | ||
| let current = try seek(offset: 0, from: .current) | ||
| let size = try seek(offset: 0, from: .end) | ||
| try seek(offset: current, from: .start) |
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This is temporarily mutating the file position during what looks like a read-only operation; I feel the potential pitfalls of this (alongside the fact that many file descriptors do not have a file size) probably makes this entry point less suitable for this package.
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That's reasonable. I added the following fixup to address this:
- d90bf85
fixup: Move FileDescriptor.fileSize() to an internal extension in SystemTests
| @inline(__always) | ||
| internal func ftruncate( | ||
| _ fd: Int32, _ length: off_t | ||
| ) -> Int32 { | ||
| _chsize(fd, numericCast(length)) | ||
| } |
There was a problem hiding this comment.
I believe it's best to surround the addition of resize with #if !os(Windows).
Generally, I don't think it's a good idea to try to shoehorn Windows support into POSIX code paths here, or anywhere else in this code base. Swift System is not intended to provide a portable API layer, and the Windows SDK is different enough that it deserves its own, standalone, implementations.
There was a problem hiding this comment.
Thanks @lorentey for the review!
Big thumbs up on
resize! I'm less convinced we needfileSize.
No problem, I moved fileSize to be an implementation detail of the tests for resize.
Let's keep the Windows implementation out for now.
Done.
I also updated the PR description to reflect the changes.
Sources/System/FileHelpers.swift
Outdated
| ) throws -> Int64 { | ||
| let current = try seek(offset: 0, from: .current) | ||
| let size = try seek(offset: 0, from: .end) | ||
| try seek(offset: current, from: .start) |
There was a problem hiding this comment.
That's reasonable. I added the following fixup to address this:
- d90bf85
fixup: Move FileDescriptor.fileSize() to an internal extension in SystemTests
| @inline(__always) | ||
| internal func ftruncate( | ||
| _ fd: Int32, _ length: off_t | ||
| ) -> Int32 { | ||
| _chsize(fd, numericCast(length)) | ||
| } |
There was a problem hiding this comment.
OK, apologies for that, I was just following the pattern I saw with the existing WindowsSyscallAdapters. I added some fixups which move this API to only non-Windows platforms:
|
@swift-ci please test |
Signed-off-by: Si Beaumont <beaumont@apple.com>
|
@swift-ci please test |
Signed-off-by: Si Beaumont <beaumont@apple.com>
|
@swift-ci please test |
The
FileDescriptorAPI currently doesn't expose anything that resemblesftruncate(2)for truncating or extending the file associated with a file descriptor.This PR adds a new API
FileDescriptor.resize(to newSize:)which wrapsftruncate, available on non-Windows platforms.