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Simplify file size related code

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This commit is contained in:
Rafał Harabień 2018-10-10 22:03:00 +02:00
parent 1724a54536
commit 534781963b
2 changed files with 25 additions and 22 deletions
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2
src/dir_entry.rs
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@ -187,7 +187,7 @@ impl DirFileEntryData {
self.size = size;
}
fn is_dir(&self) -> bool {
pub(crate) fn is_dir(&self) -> bool {
self.attrs.contains(FileAttributes::DIRECTORY)
}

41
src/file.rs
View File

@ -124,13 +124,25 @@ impl<'a, T: ReadWriteSeek> File<'a, T> {
}
}
fn bytes_left_in_file(&self) -> Option<usize> {
fn size(&self) -> Option<u32> {
match self.entry {
Some(ref e) => e.inner().size().map(|s| (s - self.offset) as usize),
Some(ref e) => e.inner().size(),
None => None,
}
}
fn is_dir(&self) -> bool {
match self.entry {
Some(ref e) => e.inner().is_dir(),
None => false,
}
}
fn bytes_left_in_file(&self) -> Option<usize> {
// Note: seeking beyond end of file is not allowed so overflow is impossible
self.size().map(|s| (s - self.offset) as usize)
}
fn set_first_cluster(&mut self, cluster: u32) {
self.first_cluster = Some(cluster);
if let Some(ref mut e) = self.entry {
@ -254,9 +266,9 @@ impl<'a, T: ReadWriteSeek> Write for File<'a, T> {
if self.first_cluster.is_none() {
self.set_first_cluster(new_cluster);
}
if self.entry.iter().next().map_or(true, |e| e.inner().size().is_none()) {
if self.is_dir() {
// zero new directory cluster
trace!("zeroing directory cluser {}", new_cluster);
trace!("zeroing directory cluster {}", new_cluster);
let abs_pos = self.fs.offset_from_cluster(new_cluster);
let mut disk = self.fs.disk.borrow_mut();
disk.seek(SeekFrom::Start(abs_pos))?;
@ -305,31 +317,22 @@ impl<'a, T: ReadWriteSeek> Seek for File<'a, T> {
SeekFrom::Current(x) => self.offset as i64 + x,
SeekFrom::Start(x) => x as i64,
SeekFrom::End(x) => {
let size = self
.entry
.iter()
.next()
.map_or(None, |e| e.inner().size())
.expect("cannot seek from end if size is unknown") as i64;
let size = self.size().expect("cannot seek from end if size is unknown") as i64;
size + x
},
};
if new_pos < 0 {
return Err(io::Error::new(ErrorKind::InvalidInput, "Seek to a negative offset"));
}
new_pos = match self.entry {
Some(ref e) => {
if e.inner().size().map_or(false, |s| new_pos > s as i64) {
if let Some(s) = self.size() {
if new_pos > s as i64 {
info!("seek beyond end of file");
e.inner().size().unwrap() as i64 // SAFE: map_or returns false if size is empty
} else {
new_pos
new_pos = s as i64;
}
}
},
_ => new_pos,
};
trace!("file seek {} -> {} - entry {:?}", self.offset, new_pos, self.entry);
if new_pos == self.offset as i64 {
// position is the same - nothing to do
return Ok(self.offset as u64);
}
let cluster_size = self.fs.cluster_size();