blob: ce9fa2963ec8f0f135d42974a5438ddaf82761ca [file] [log] [blame] [edit]
// Copyright 2019 Intel Corporation. All Rights Reserved.
//
// Copyright 2018 The Chromium OS Authors. All rights reserved.
//
// SPDX-License-Identifier: BSD-3-Clause
//! Traits for handling file synchronization and length.
use std::fs::File;
use std::io::Result;
/// A trait for flushing the contents of a file to disk.
///
/// This is equivalent to
/// [`std::fd::File::sync_all`](https://doc.rust-lang.org/std/fs/struct.File.html#method.sync_all)
/// method, but wrapped in a trait so that it can be implemented for other types.
pub trait FileSync {
/// Flush buffers related to this file to disk.
fn fsync(&mut self) -> Result<()>;
}
impl FileSync for File {
fn fsync(&mut self) -> Result<()> {
self.sync_all()
}
}
/// A trait for setting the size of a file.
///
/// This is equivalent to
/// [`std::fd::File::set_len`](https://doc.rust-lang.org/std/fs/struct.File.html#method.set_len)
/// method, but wrapped in a trait so that it can be implemented for other types.
pub trait FileSetLen {
/// Set the size of this file.
///
/// This is the moral equivalent of
/// [`ftruncate`](http://man7.org/linux/man-pages/man3/ftruncate.3p.html).
///
/// # Arguments
///
/// * `len`: the size to set for file.
fn set_len(&self, len: u64) -> Result<()>;
}
impl FileSetLen for File {
fn set_len(&self, len: u64) -> Result<()> {
File::set_len(self, len)
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::fs::OpenOptions;
use std::io::{Seek, SeekFrom, Write};
use std::path::PathBuf;
use crate::tempdir::TempDir;
#[test]
fn test_fsync() {
let tempdir = TempDir::new_with_prefix("/tmp/fsync_test").unwrap();
let mut path = PathBuf::from(tempdir.as_path());
path.push("file");
let mut f = OpenOptions::new()
.read(true)
.write(true)
.create(true)
.open(&path)
.unwrap();
f.write_all(b"Hello, world!").unwrap();
f.fsync().unwrap();
assert_eq!(f.metadata().unwrap().len(), 13);
}
#[test]
fn test_set_len() {
let tempdir = TempDir::new_with_prefix("/tmp/set_len_test").unwrap();
let mut path = PathBuf::from(tempdir.as_path());
path.push("file");
let mut f = OpenOptions::new()
.read(true)
.write(true)
.create(true)
.open(&path)
.unwrap();
f.set_len(10).unwrap();
assert_eq!(f.seek(SeekFrom::End(0)).unwrap(), 10);
}
#[test]
fn test_set_len_fails_when_file_not_opened_for_writing() {
let tempdir = TempDir::new_with_prefix("/tmp/set_len_test").unwrap();
let mut path = PathBuf::from(tempdir.as_path());
path.push("file");
File::create(path.clone()).unwrap();
let f = OpenOptions::new().read(true).open(&path).unwrap();
let result = f.set_len(10);
assert!(result.is_err());
}
}