matthiasbeyer/imag
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Seek to beginning of file before reading

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This commit is contained in:
Marcel Müller 2016-01-18 18:43:36 +01:00
parent 4e0e80c0b8
commit 1c73fcfae1
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GPG key ID: DD4ED37D0CAC76E2
1 changed files with 15 additions and 20 deletions
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35
libimagstore/src/lazyfile.rs
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@ -1,5 +1,6 @@
use error::{StoreError, StoreErrorKind};
use std::io::{Seek, SeekFrom};
use std::path::{Path, PathBuf};
use std::fs::{File, OpenOptions};
@ -25,26 +26,22 @@ impl LazyFile {
}
pub fn get_file(&mut self) -> Result<&File, StoreError> {
let file = match *self {
LazyFile::File(ref f) => return Ok(f),
LazyFile::Absent(ref p) => {
try!(open_file(p).map_err(|e| {
StoreError::new(StoreErrorKind::FileNotFound,
Some(Box::new(e)))
}))
}
};
*self = LazyFile::File(file);
if let LazyFile::File(ref f) = *self {
return Ok(f);
match self.get_file_mut() {
Ok(file) => Ok(&*file),
Err(e) => Err(e)
}
unreachable!()
}
pub fn get_file_mut(&mut self) -> Result<&mut File, StoreError> {
let file = match *self {
LazyFile::File(ref mut f) => return Ok(f),
LazyFile::File(ref mut f) => return {
// We seek to the beginning of the file since we expect each
// access to the file to be in a different context
f.seek(SeekFrom::Start(0)).map_err(|e|
StoreError::new(
StoreErrorKind::FileNotCreated, Some(Box::new(e))));
Ok(f)
},
LazyFile::Absent(ref p) => {
try!(open_file(p).map_err(|e| {
StoreError::new(StoreErrorKind::FileNotFound,
@ -80,7 +77,7 @@ impl LazyFile {
#[cfg(test)]
mod test {
use super::LazyFile;
use std::io::{Read, Write};
use std::io::{Read, Write, Seek, SeekFrom};
use std::path::PathBuf;
use std::fs::File;
use tempdir::TempDir;
@ -105,9 +102,9 @@ mod test {
let dir = get_dir();
let mut path = PathBuf::from(dir.path());
path.set_file_name("test2");
let mut lf = LazyFile::new(path.clone());
{
let mut lf = LazyFile::new(path.clone());
let mut file = lf.create_file().unwrap();
file.write(b"Hello World").unwrap();
@ -115,9 +112,7 @@ mod test {
}
{
let mut lf = LazyFile::new(path);
let mut file = lf.create_file().unwrap();
let mut file = lf.get_file().unwrap();
let mut s = Vec::new();
file.read_to_end(&mut s).unwrap();
assert_eq!(s, "Hello World".to_string().into_bytes());