Auto merge of #98246 - joshtriplett:times, r=m-ou-se

Support setting file accessed/modified timestamps

Add `struct FileTimes` to contain the relevant file timestamps, since
most platforms require setting all of them at once. (This also allows
for future platform-specific extensions such as setting creation time.)

Add `File::set_file_time` to set the timestamps for a `File`.

Implement the `sys` backends for UNIX, macOS (which needs to fall back
to `futimes` before macOS 10.13 because it lacks `futimens`), Windows,
and WASI.

3 files changed, 45 insertions, 1 deletions

diff --git a/library/std/src/sys/windows/c.rs b/library/std/src/sys/windows/c.rs
index e9c20850420..478068c73ba 100644
--- a/library/std/src/sys/windows/c.rs
+++ b/library/std/src/sys/windows/c.rs
@@ -620,7 +620,7 @@ pub struct SOCKADDR {
 }
 
 #[repr(C)]
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, Debug, Default)]
 pub struct FILETIME {
     pub dwLowDateTime: DWORD,
     pub dwHighDateTime: DWORD,
@@ -888,6 +888,12 @@ extern "system" {
     pub fn GetSystemDirectoryW(lpBuffer: LPWSTR, uSize: UINT) -> UINT;
     pub fn RemoveDirectoryW(lpPathName: LPCWSTR) -> BOOL;
     pub fn SetFileAttributesW(lpFileName: LPCWSTR, dwFileAttributes: DWORD) -> BOOL;
+    pub fn SetFileTime(
+        hFile: BorrowedHandle<'_>,
+        lpCreationTime: Option<&FILETIME>,
+        lpLastAccessTime: Option<&FILETIME>,
+        lpLastWriteTime: Option<&FILETIME>,
+    ) -> BOOL;
     pub fn SetLastError(dwErrCode: DWORD);
     pub fn GetCommandLineW() -> LPWSTR;
     pub fn GetTempPathW(nBufferLength: DWORD, lpBuffer: LPCWSTR) -> DWORD;
diff --git a/library/std/src/sys/windows/fs.rs b/library/std/src/sys/windows/fs.rs
index c96bcf41d51..aed082b3e0a 100644
--- a/library/std/src/sys/windows/fs.rs
+++ b/library/std/src/sys/windows/fs.rs
@@ -83,6 +83,12 @@ pub struct FilePermissions {
     attrs: c::DWORD,
 }
 
+#[derive(Copy, Clone, Debug, Default)]
+pub struct FileTimes {
+    accessed: Option<c::FILETIME>,
+    modified: Option<c::FILETIME>,
+}
+
 #[derive(Debug)]
 pub struct DirBuilder;
 
@@ -536,6 +542,21 @@ impl File {
         })?;
         Ok(())
     }
+
+    pub fn set_times(&self, times: FileTimes) -> io::Result<()> {
+        let is_zero = |t: c::FILETIME| t.dwLowDateTime == 0 && t.dwHighDateTime == 0;
+        if times.accessed.map_or(false, is_zero) || times.modified.map_or(false, is_zero) {
+            return Err(io::const_io_error!(
+                io::ErrorKind::InvalidInput,
+                "Cannot set file timestamp to 0",
+            ));
+        }
+        cvt(unsafe {
+            c::SetFileTime(self.as_handle(), None, times.accessed.as_ref(), times.modified.as_ref())
+        })?;
+        Ok(())
+    }
+
     /// Get only basic file information such as attributes and file times.
     fn basic_info(&self) -> io::Result<c::FILE_BASIC_INFO> {
         unsafe {
@@ -903,6 +924,16 @@ impl FilePermissions {
     }
 }
 
+impl FileTimes {
+    pub fn set_accessed(&mut self, t: SystemTime) {
+        self.accessed = Some(t.into_inner());
+    }
+
+    pub fn set_modified(&mut self, t: SystemTime) {
+        self.modified = Some(t.into_inner());
+    }
+}
+
 impl FileType {
     fn new(attrs: c::DWORD, reparse_tag: c::DWORD) -> FileType {
         FileType { attributes: attrs, reparse_tag }
diff --git a/library/std/src/sys/windows/time.rs b/library/std/src/sys/windows/time.rs
index 8f46781c753..b8209a85445 100644
--- a/library/std/src/sys/windows/time.rs
+++ b/library/std/src/sys/windows/time.rs
@@ -2,6 +2,7 @@ use crate::cmp::Ordering;
 use crate::fmt;
 use crate::mem;
 use crate::sys::c;
+use crate::sys_common::IntoInner;
 use crate::time::Duration;
 
 use core::hash::{Hash, Hasher};
@@ -136,6 +137,12 @@ impl From<c::FILETIME> for SystemTime {
     }
 }
 
+impl IntoInner<c::FILETIME> for SystemTime {
+    fn into_inner(self) -> c::FILETIME {
+        self.t
+    }
+}
+
 impl Hash for SystemTime {
     fn hash<H: Hasher>(&self, state: &mut H) {
         self.intervals().hash(state)