Commit 5b08fafa authored by Simon Sapin's avatar Simon Sapin
Browse files

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
parent e10f5dc7f5bf
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 @@ impl TruncatedTimestamp {
}
}
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 @@ impl TruncatedTimestamp {
/// 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 {
......
......@@ -199,15 +199,14 @@ impl<'a, 'tree, 'on_disk> StatusCommon<'a, 'tree, 'on_disk> {
// 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 @@ impl<'a, 'tree, 'on_disk> StatusCommon<'a, 'tree, 'on_disk> {
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
};
......
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