tfio/
write.rs

1use std::io::{self, Read, Write};
2use std::{
3    fs::OpenOptions,
4    path::{Path, PathBuf},
5};
6
7use crate::{RollbackableOperation, SingleFileOperation};
8
9/// Writes data to a file
10pub struct WriteFile {
11    source: PathBuf,
12    temp_dir: PathBuf,
13    backup_path: PathBuf,
14    data: Vec<u8>,
15}
16
17impl WriteFile {
18    /// Constructs a new WriteFile operation
19    pub fn new<S: AsRef<Path>, T: AsRef<Path>>(source: S, temp_dir: T, data: Vec<u8>) -> Self {
20        Self {
21            source: source.as_ref().into(),
22            temp_dir: temp_dir.as_ref().into(),
23            backup_path: PathBuf::new(),
24            data: data,
25        }
26    }
27}
28
29impl RollbackableOperation for WriteFile {
30    fn execute(&mut self) -> io::Result<()> {
31        self.create_backup_file()?;
32
33        OpenOptions::new()
34            .write(true)
35            .open(self.get_path())?
36            .write_all(&self.data)
37    }
38
39    fn rollback(&self) -> io::Result<()> {
40        let mut buffer = Vec::<u8>::new();
41        let mut backup_file = OpenOptions::new().read(true).open(self.get_backup_path())?;
42
43        backup_file.read_to_end(&mut buffer)?;
44
45        OpenOptions::new()
46            .write(true)
47            .truncate(true)
48            .open(self.get_path())?
49            .write_all(&buffer)
50    }
51}
52
53impl SingleFileOperation for WriteFile {
54    fn get_path(&self) -> &Path {
55        &self.source
56    }
57
58    fn get_backup_path(&self) -> &Path {
59        &self.backup_path
60    }
61
62    fn set_backup_path<S: AsRef<Path>>(&mut self, uuid: S) {
63        self.backup_path = uuid.as_ref().into();
64    }
65
66    fn get_temp_dir(&self) -> &Path {
67        &self.temp_dir
68    }
69}
70
71impl Drop for WriteFile {
72    fn drop(&mut self) {
73        match self.dispose() {
74            Err(e) => eprintln!("{}", e),
75            _ => {}
76        }
77    }
78}
79
80#[cfg(test)]
81mod tests {
82    use std::fs::{self, File};
83
84    use super::*;
85
86    const FILE_SOURCE: &str = "./write_file_source.txt";
87    const TEMP_DIR: &str = "./tmp/";
88    const INITIAL_DATA: &[u8] = "Yellow World".as_bytes();
89    const WRITTEN_DATA: &[u8] = "Hello World".as_bytes();
90
91    fn write_setup() -> std::io::Result<()> {
92        match File::create(FILE_SOURCE) {
93            Ok(_f) => Ok(()),
94            Err(e) => Err(e),
95        }
96    }
97
98    #[test]
99    #[allow(unused_must_use)]
100    fn write_file_works() {
101        assert_eq!((), write_setup().unwrap());
102
103        fs::write(FILE_SOURCE, INITIAL_DATA).expect("Unable to write file");
104
105        let mut op = WriteFile::new(FILE_SOURCE, TEMP_DIR, WRITTEN_DATA.to_vec());
106
107        assert_eq!((), op.execute().unwrap());
108        let data = fs::read_to_string(FILE_SOURCE).expect("Unable to read file");
109        assert_eq!(String::from("Hello Worldd"), data);
110
111        assert_eq!((), op.rollback().unwrap());
112        let data = fs::read_to_string(FILE_SOURCE).expect("Unable to read file");
113        assert_eq!(String::from_utf8(INITIAL_DATA.to_vec()).unwrap(), data);
114
115        fs::remove_file(FILE_SOURCE);
116    }
117}
tfio/write.rs

tfio/
write.rs
