Stat implementation for Swift System by jrflat · Pull Request #256 · apple/swift-system

jrflat · 2025-08-12T18:14:36Z

This PR adds a Swift Stat implementation for the C stat types and system calls.

See the pitch at https://forums.swift.org/t/pitch-stat-types-for-swift-system/81616
See the full proposal in #257

jrflat · 2025-08-12T18:37:50Z

Note that the implementation uses typed throws which require Swift 6.0+, so earlier Swift versions are failing.

stephentyrone · 2025-08-26T16:23:44Z

Package.swift


 let cSettings: [CSetting] = [
  .define("_CRT_SECURE_NO_WARNINGS", .when(platforms: [.windows])),
+  .define("_GNU_SOURCE", .when(platforms: [.linux])),


I vaguely remember that this may cause an issue with the glibc module if another package imports it without this define? I.e. either everyone has to import it this way or no one can (in which case, we really want the C importer to set this instead of setting it in the package). @DougGregor?

rauhul · 2025-08-27T23:46:12Z

I would really like native TimeSpec and TimeVal wrappers to be provided by this API and conversions to/from duration be based on them.

These type represent the granularity the system thinks in and papering over that with Duration/UTCClock.instant is silly. The system cannot represent all of these values. Swift-system is supported to provide type-safe access to the system api not high level abstractions, thats best left to Foundation.

jrflat · 2025-08-28T17:23:29Z

I would really like native TimeSpec and TimeVal wrappers to be provided by this API and conversions to/from duration be based on them.

The stdlib already provides initializers to convert timespec and timeval to/from Duration, so I'm not sure if it's worth it to have wrappers in these cases. I think exposing the raw timespec as we're doing here is a decent compromise to allow access to the system's granularity while later providing a more ergonomic UTCClock.Instant property.

jrflat · 2025-09-29T18:39:35Z

@swift-ci please test

jrflat · 2025-10-06T19:33:50Z

@swift-ci please test

glessard · 2025-10-28T03:30:52Z

Sources/System/Internals/Constants.swift

+// MARK: - fstatat Flags
+
+@_alwaysEmitIntoClient
+internal var _AT_SYMLINK_NOFOLLOW: CInt { AT_SYMLINK_FOLLOW }


Suggested change

internal var _AT_SYMLINK_NOFOLLOW: CInt { AT_SYMLINK_FOLLOW }

internal var _AT_SYMLINK_NOFOLLOW: CInt { AT_SYMLINK_NOFOLLOW }

Oops, thanks! Fixed in 90dba1d

glessard · 2025-10-28T17:23:14Z

Sources/System/FileSystem/Stat.swift

+  /// Total size, in bytes
+  ///
+  /// The semantics of this property are tied to the underlying C `st_size` field,
+  /// which can have file system-dependent behavior. For example, this property


Suggested change

/// which can have file system-dependent behavior. For example, this property

/// which can have filesystem-dependent behavior. For example, this property

We use the one-word "filesystem" elsewhere, so this seems like a typo.

Apart from where I used "filesystem" below, it actually looks like all prior uses in System are written "file system" or capitalized "FileSystem" (except for one), so I settled on "file system" in eee0145.

After some research, I did find that "file system-dependent" is not correct grammar and instead should be written "file-system-dependent" or "file-system–dependent" (with an en dash in the second gap) if we want to match the use of "file system." I've opted for "file-system–dependent" since it's a neat way to use an en dash to highlight the grouping of "file-system" in a larger compound modifier, but I don't feel super strongly about it if we want to change it (or even replace all uses with "filesystem") 😄

glessard · 2025-10-28T17:37:48Z

Sources/System/FileSystem/Stat.swift

+  }
+  #endif
+
+  // TODO: Investigate changing time properties to UTCClock.Instant once available.


Let's remove the commented-out lines in a standalone commit so that they're easy to find later, instead of leaving commented-out code.

Done! 501bb7d

…orms

jrflat · 2025-10-29T18:57:16Z

@swift-ci please test

jrflat · 2025-10-30T20:19:21Z

@swift-ci please test

jrflat · 2025-11-03T05:34:31Z

@swift-ci please test

marcprux · 2025-11-04T00:13:45Z

Sources/System/Internals/CInterop.swift

+#if !os(Windows)
+@available(System 99, *)
+extension CInterop {
+  public typealias Stat = stat


This breaks the Android build:

/home/runner/work/swift-android-sdk-build/swift-android-sdk-build/swift-system/Sources/System/Internals/CInterop.swift:86:27: error: cannot use struct 'stat' here; 'posix_filesystem' has been imported as implementation-only

In the future, we'll catch this if #269 is merged.

Ah thanks for catching this and putting up that PR to enable the Android build! I'll get this fixed then we can land your PR with the build green.

stephentyrone reviewed Aug 26, 2025

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jrflat force-pushed the stat-implementation branch 2 times, most recently from 266636c to 2f0f045 Compare August 26, 2025 23:54

jrflat added 4 commits September 29, 2025 11:34

Stat implementation

57d515e

Fix AT_RESOLVE_BENEATH availability

a07696a

Expose C timespec properties until UTCClock can be used

905f9f8

Updates for proposal v3

2f5b12b

jrflat force-pushed the stat-implementation branch from 2f0f045 to 2f5b12b Compare September 29, 2025 18:06

jrflat marked this pull request as ready for review September 29, 2025 18:39

jrflat requested review from glessard, lorentey and milseman as code owners September 29, 2025 18:39

Remove _GNU_SOURCE define and AT_EMPTY_PATH for now

98712f6

glessard reviewed Oct 28, 2025

View reviewed changes

glessard approved these changes Oct 28, 2025

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jrflat added 6 commits October 28, 2025 22:30

Remove commented-out code for future directions

501bb7d

AT_SYMLINK_FOLLOW -> AT_SYMLINK_NOFOLLOW

90dba1d

Standardize on "file system"

eee0145

Consolidate internal Stat functions

40e1deb

Add availability, fix CInterop availability issue on old Darwin platf…

4911642

…orms

Remove commented-out code pt. 2

c2e385e

Assign rawValue instead of self

87f8e49

Add availability to new CInterop typealiases

55350cd

glessard approved these changes Nov 3, 2025

View reviewed changes

jrflat merged commit b11b33a into apple:main Nov 3, 2025
56 checks passed

marcprux reviewed Nov 4, 2025

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glessard mentioned this pull request Nov 13, 2025

[DRAFT][SKETCH] Ideas for stat.h interface #56

Closed

	internal var _AT_SYMLINK_NOFOLLOW: CInt { AT_SYMLINK_FOLLOW }
	internal var _AT_SYMLINK_NOFOLLOW: CInt { AT_SYMLINK_NOFOLLOW }

	/// which can have file system-dependent behavior. For example, this property
	/// which can have filesystem-dependent behavior. For example, this property

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jrflat commented Aug 12, 2025 •

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