status: Extract TruncatedTimestamp from fs::Metadata without SystemTime
On Unix, the Rust standard library exposes `mtime` and `mtime_nsec` methods
for `std::fs::Metada` whih is exactly what we need to construct a
`TruncatedTimestamp`. This skips the computation in the conversion through
`SystemTime` and `Result<Duration, Duration>`.
Differential Revision: https://phab.mercurial-scm.org/D11654
--- a/rust/hg-core/src/dirstate/entry.rs Fri Sep 17 15:07:30 2021 -0400
+++ b/rust/hg-core/src/dirstate/entry.rs Wed Oct 13 16:21:39 2021 +0200
@@ -1,7 +1,9 @@
use crate::dirstate_tree::on_disk::DirstateV2ParseError;
use crate::errors::HgError;
use bitflags::bitflags;
-use std::convert::TryFrom;
+use std::convert::{TryFrom, TryInto};
+use std::fs;
+use std::io;
use std::time::{SystemTime, UNIX_EPOCH};
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
@@ -69,6 +71,21 @@
}
}
+ pub fn for_mtime_of(metadata: &fs::Metadata) -> io::Result<Self> {
+ #[cfg(unix)]
+ {
+ use std::os::unix::fs::MetadataExt;
+ let seconds = metadata.mtime();
+ // i64 -> u32 with value always in the `0 .. NSEC_PER_SEC` range
+ let nanoseconds = metadata.mtime_nsec().try_into().unwrap();
+ Ok(Self::new_truncate(seconds, nanoseconds))
+ }
+ #[cfg(not(unix))]
+ {
+ metadata.modified().map(Self::from)
+ }
+ }
+
/// The lower 31 bits of the number of seconds since the epoch.
pub fn truncated_seconds(&self) -> u32 {
self.truncated_seconds
@@ -93,10 +110,17 @@
/// If someone is manipulating the modification times of some files to
/// intentionally make `hg status` return incorrect results, not truncating
/// wouldn’t help much since they can set exactly the expected timestamp.
- pub fn very_likely_equal(&self, other: &Self) -> bool {
+ pub fn very_likely_equal(self, other: Self) -> bool {
self.truncated_seconds == other.truncated_seconds
&& self.nanoseconds == other.nanoseconds
}
+
+ pub fn very_likely_equal_to_mtime_of(
+ self,
+ metadata: &fs::Metadata,
+ ) -> io::Result<bool> {
+ Ok(self.very_likely_equal(Self::for_mtime_of(metadata)?))
+ }
}
impl From<SystemTime> for TruncatedTimestamp {
--- a/rust/hg-core/src/dirstate_tree/status.rs Fri Sep 17 15:07:30 2021 -0400
+++ b/rust/hg-core/src/dirstate_tree/status.rs Wed Oct 13 16:21:39 2021 +0200
@@ -199,15 +199,14 @@
// by a previous run of the `status` algorithm which found this
// directory eligible for `read_dir` caching.
if let Some(meta) = directory_metadata {
- if let Ok(current_mtime) = meta.modified() {
- let truncated =
- TruncatedTimestamp::from(current_mtime);
- if truncated.very_likely_equal(&cached_mtime) {
- // The mtime of that directory has not changed
- // since then, which means that the results of
- // `read_dir` should also be unchanged.
- return true;
- }
+ if cached_mtime
+ .very_likely_equal_to_mtime_of(meta)
+ .unwrap_or(false)
+ {
+ // The mtime of that directory has not changed
+ // since then, which means that the results of
+ // `read_dir` should also be unchanged.
+ return true;
}
}
}
@@ -472,7 +471,7 @@
let is_up_to_date = if let Some(cached) =
dirstate_node.cached_directory_mtime()?
{
- cached.very_likely_equal(&truncated)
+ cached.very_likely_equal(truncated)
} else {
false
};