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use std::io::{self, Read, Write};
use std::{
fs::OpenOptions,
path::{Path, PathBuf},
};
use crate::{RollbackableOperation, SingleFileOperation};
pub struct WriteFile {
source: PathBuf,
temp_dir: PathBuf,
backup_path: PathBuf,
data: Vec<u8>,
}
impl WriteFile {
pub fn new<S: AsRef<Path>, T: AsRef<Path>>(source: S, temp_dir: T, data: Vec<u8>) -> Self {
Self {
source: source.as_ref().into(),
temp_dir: temp_dir.as_ref().into(),
backup_path: PathBuf::new(),
data: data,
}
}
}
impl RollbackableOperation for WriteFile {
fn execute(&mut self) -> io::Result<()> {
self.create_backup_file()?;
OpenOptions::new()
.write(true)
.open(self.get_path())?
.write_all(&self.data)
}
fn rollback(&self) -> io::Result<()> {
let mut buffer = Vec::<u8>::new();
let mut backup_file = OpenOptions::new().read(true).open(self.get_backup_path())?;
backup_file.read_to_end(&mut buffer)?;
OpenOptions::new()
.write(true)
.truncate(true)
.open(self.get_path())?
.write_all(&buffer)
}
}
impl SingleFileOperation for WriteFile {
fn get_path(&self) -> &Path {
&self.source
}
fn get_backup_path(&self) -> &Path {
&self.backup_path
}
fn set_backup_path<S: AsRef<Path>>(&mut self, uuid: S) {
self.backup_path = uuid.as_ref().into();
}
fn get_temp_dir(&self) -> &Path {
&self.temp_dir
}
}
impl Drop for WriteFile {
fn drop(&mut self) {
match self.dispose() {
Err(e) => eprintln!("{}", e),
_ => {}
}
}
}
#[cfg(test)]
mod tests {
use std::fs::{self, File};
use super::*;
const FILE_SOURCE: &str = "./write_file_source.txt";
const TEMP_DIR: &str = "./tmp/";
const INITIAL_DATA: &[u8] = "Yellow World".as_bytes();
const WRITTEN_DATA: &[u8] = "Hello World".as_bytes();
fn write_setup() -> std::io::Result<()> {
match File::create(FILE_SOURCE) {
Ok(_f) => Ok(()),
Err(e) => Err(e),
}
}
#[test]
#[allow(unused_must_use)]
fn write_file_works() {
assert_eq!((), write_setup().unwrap());
fs::write(FILE_SOURCE, INITIAL_DATA).expect("Unable to write file");
let mut op = WriteFile::new(FILE_SOURCE, TEMP_DIR, WRITTEN_DATA.to_vec());
assert_eq!((), op.execute().unwrap());
let data = fs::read_to_string(FILE_SOURCE).expect("Unable to read file");
assert_eq!(String::from("Hello Worldd"), data);
assert_eq!((), op.rollback().unwrap());
let data = fs::read_to_string(FILE_SOURCE).expect("Unable to read file");
assert_eq!(String::from_utf8(INITIAL_DATA.to_vec()).unwrap(), data);
fs::remove_file(FILE_SOURCE);
}
}