##// END OF EJS Templates
rust-index: implement common_ancestors_heads() and ancestors()...
rust-index: implement common_ancestors_heads() and ancestors() The only differences betwwen `common_ancestors_heads()` and `find_gca_candidates()` seems to be that: - the former accepts "overlapping" input revisions (meaning with duplicates). - limitation to 24 inputs (in the C code), that we translate to using the arbitrary size bit sets in the Rust code because we cannot bail to Python. Given that the input is expected to be small in most cases, we take the heavy handed approach of going through a HashSet and wait for perfomance assessment In case this is used via `hg-cpython`, we can anyway absorb the overhead by having `commonancestorheads` build a vector of unique values directly, and introduce a thin wrapper over `find_gca_candidates`, to take care of bit set type dispatching only. As far as `ancestors` is concerneed, this is just chaining `common_ancestors_heads()` with `find_deepest_revs`.

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r51182:0cc19a53 stable
r52118:89ce6a49 default
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vfs.rs
205 lines | 6.4 KiB | application/rls-services+xml | RustLexer
use crate::errors::{HgError, IoErrorContext, IoResultExt};
use memmap2::{Mmap, MmapOptions};
use std::io::{ErrorKind, Write};
use std::path::{Path, PathBuf};
/// Filesystem access abstraction for the contents of a given "base" diretory
#[derive(Clone, Copy)]
pub struct Vfs<'a> {
pub(crate) base: &'a Path,
}
struct FileNotFound(std::io::Error, PathBuf);
impl Vfs<'_> {
pub fn join(&self, relative_path: impl AsRef<Path>) -> PathBuf {
self.base.join(relative_path)
}
pub fn symlink_metadata(
&self,
relative_path: impl AsRef<Path>,
) -> Result<std::fs::Metadata, HgError> {
let path = self.join(relative_path);
std::fs::symlink_metadata(&path).when_reading_file(&path)
}
pub fn read_link(
&self,
relative_path: impl AsRef<Path>,
) -> Result<PathBuf, HgError> {
let path = self.join(relative_path);
std::fs::read_link(&path).when_reading_file(&path)
}
pub fn read(
&self,
relative_path: impl AsRef<Path>,
) -> Result<Vec<u8>, HgError> {
let path = self.join(relative_path);
std::fs::read(&path).when_reading_file(&path)
}
/// Returns `Ok(None)` if the file does not exist.
pub fn try_read(
&self,
relative_path: impl AsRef<Path>,
) -> Result<Option<Vec<u8>>, HgError> {
match self.read(relative_path) {
Err(e) => match &e {
HgError::IoError { error, .. } => match error.kind() {
ErrorKind::NotFound => Ok(None),
_ => Err(e),
},
_ => Err(e),
},
Ok(v) => Ok(Some(v)),
}
}
fn mmap_open_gen(
&self,
relative_path: impl AsRef<Path>,
) -> Result<Result<Mmap, FileNotFound>, HgError> {
let path = self.join(relative_path);
let file = match std::fs::File::open(&path) {
Err(err) => {
if let ErrorKind::NotFound = err.kind() {
return Ok(Err(FileNotFound(err, path)));
};
return (Err(err)).when_reading_file(&path);
}
Ok(file) => file,
};
// TODO: what are the safety requirements here?
let mmap = unsafe { MmapOptions::new().map(&file) }
.when_reading_file(&path)?;
Ok(Ok(mmap))
}
pub fn mmap_open_opt(
&self,
relative_path: impl AsRef<Path>,
) -> Result<Option<Mmap>, HgError> {
self.mmap_open_gen(relative_path).map(|res| res.ok())
}
pub fn mmap_open(
&self,
relative_path: impl AsRef<Path>,
) -> Result<Mmap, HgError> {
match self.mmap_open_gen(relative_path)? {
Err(FileNotFound(err, path)) => Err(err).when_reading_file(&path),
Ok(res) => Ok(res),
}
}
pub fn rename(
&self,
relative_from: impl AsRef<Path>,
relative_to: impl AsRef<Path>,
) -> Result<(), HgError> {
let from = self.join(relative_from);
let to = self.join(relative_to);
std::fs::rename(&from, &to)
.with_context(|| IoErrorContext::RenamingFile { from, to })
}
pub fn remove_file(
&self,
relative_path: impl AsRef<Path>,
) -> Result<(), HgError> {
let path = self.join(relative_path);
std::fs::remove_file(&path)
.with_context(|| IoErrorContext::RemovingFile(path))
}
#[cfg(unix)]
pub fn create_symlink(
&self,
relative_link_path: impl AsRef<Path>,
target_path: impl AsRef<Path>,
) -> Result<(), HgError> {
let link_path = self.join(relative_link_path);
std::os::unix::fs::symlink(target_path, &link_path)
.when_writing_file(&link_path)
}
/// Write `contents` into a temporary file, then rename to `relative_path`.
/// This makes writing to a file "atomic": a reader opening that path will
/// see either the previous contents of the file or the complete new
/// content, never a partial write.
pub fn atomic_write(
&self,
relative_path: impl AsRef<Path>,
contents: &[u8],
) -> Result<(), HgError> {
let mut tmp = tempfile::NamedTempFile::new_in(self.base)
.when_writing_file(self.base)?;
tmp.write_all(contents)
.and_then(|()| tmp.flush())
.when_writing_file(tmp.path())?;
let path = self.join(relative_path);
tmp.persist(&path)
.map_err(|e| e.error)
.when_writing_file(&path)?;
Ok(())
}
}
fn fs_metadata(
path: impl AsRef<Path>,
) -> Result<Option<std::fs::Metadata>, HgError> {
let path = path.as_ref();
match std::fs::metadata(path) {
Ok(meta) => Ok(Some(meta)),
Err(error) => match error.kind() {
// TODO: when we require a Rust version where `NotADirectory` is
// stable, invert this logic and return None for it and `NotFound`
// and propagate any other error.
ErrorKind::PermissionDenied => Err(error).with_context(|| {
IoErrorContext::ReadingMetadata(path.to_owned())
}),
_ => Ok(None),
},
}
}
pub(crate) fn is_dir(path: impl AsRef<Path>) -> Result<bool, HgError> {
Ok(fs_metadata(path)?.map_or(false, |meta| meta.is_dir()))
}
pub(crate) fn is_file(path: impl AsRef<Path>) -> Result<bool, HgError> {
Ok(fs_metadata(path)?.map_or(false, |meta| meta.is_file()))
}
/// Returns whether the given `path` is on a network file system.
/// Taken from `cargo`'s codebase.
#[cfg(target_os = "linux")]
pub(crate) fn is_on_nfs_mount(path: impl AsRef<Path>) -> bool {
use std::ffi::CString;
use std::mem;
use std::os::unix::prelude::*;
let path = match CString::new(path.as_ref().as_os_str().as_bytes()) {
Ok(path) => path,
Err(_) => return false,
};
unsafe {
let mut buf: libc::statfs = mem::zeroed();
let r = libc::statfs(path.as_ptr(), &mut buf);
r == 0 && buf.f_type as u32 == libc::NFS_SUPER_MAGIC as u32
}
}
/// Similar to what Cargo does; although detecting NFS (or non-local
/// file systems) _should_ be possible on other operating systems,
/// we'll just assume that mmap() works there, for now; after all,
/// _some_ functionality is better than a compile error, i.e. none at
/// all
#[cfg(not(target_os = "linux"))]
pub(crate) fn is_on_nfs_mount(_path: impl AsRef<Path>) -> bool {
false
}