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Merge pull request #1502 from matthiasbeyer/libimagstore/fs-backend-no-fd-holding

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Optimize backend impl to not hold open files
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Matthias Beyer 2018-08-26 04:16:04 +02:00 committed by GitHub
commit 5b82d53fd2
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1 changed files with 18 additions and 51 deletions
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69
lib/core/libimagstore/src/file_abstraction/fs.rs
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@ -32,10 +32,7 @@ use storeid::StoreId;
use file_abstraction::iter::PathIterator; use file_abstraction::iter::PathIterator;
#[derive(Debug)] #[derive(Debug)]
pub enum FSFileAbstractionInstance { pub struct FSFileAbstractionInstance(PathBuf);
Absent(PathBuf),
File(File, PathBuf)
}
impl FileAbstractionInstance for FSFileAbstractionInstance { impl FileAbstractionInstance for FSFileAbstractionInstance {
@ -44,32 +41,18 @@ impl FileAbstractionInstance for FSFileAbstractionInstance {
*/ */
fn get_file_content(&mut self, id: StoreId) -> Result<Entry, SE> { fn get_file_content(&mut self, id: StoreId) -> Result<Entry, SE> {
debug!("Getting lazy file: {:?}", self); debug!("Getting lazy file: {:?}", self);
let (file, path) = match *self {
FSFileAbstractionInstance::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))
.chain_err(|| SEK::FileNotSeeked)?;
let mut s = String::new(); let mut file = open_file(&self.0)
f.read_to_string(&mut s) .chain_err(|| SEK::FileNotFound)?;
.chain_err(|| SEK::IoError)
.map(|_| s) file.seek(SeekFrom::Start(0)).chain_err(|| SEK::FileNotSeeked)?;
.and_then(|s| Entry::from_str(id, &s))
}, let mut s = String::new();
FSFileAbstractionInstance::Absent(ref p) =>
(open_file(p).chain_err(|| SEK::FileNotFound)?, p.clone()), file.read_to_string(&mut s)
}; .chain_err(|| SEK::IoError)
*self = FSFileAbstractionInstance::File(file, path); .map(|_| s)
if let FSFileAbstractionInstance::File(ref mut f, _) = *self { .and_then(|s| Entry::from_str(id, &s))
let mut s = String::new();
f.read_to_string(&mut s)
.chain_err(|| SEK::IoError)
.map(|_| s)
.and_then(|s| Entry::from_str(id, &s))
} else {
unreachable!()
}
} }
/** /**
@ -78,28 +61,12 @@ impl FileAbstractionInstance for FSFileAbstractionInstance {
fn write_file_content(&mut self, buf: &Entry) -> Result<(), SE> { fn write_file_content(&mut self, buf: &Entry) -> Result<(), SE> {
use std::io::Write; use std::io::Write;
let buf = buf.to_str()?.into_bytes(); let buf = buf.to_str()?.into_bytes();
let mut file = create_file(&self.0).chain_err(|| SEK::FileNotCreated)?;
let (file, path) = match *self { file.seek(SeekFrom::Start(0)).chain_err(|| SEK::FileNotCreated)?;
FSFileAbstractionInstance::File(ref mut f, _) => return { file.set_len(buf.len() as u64).chain_err(|| SEK::FileNotWritten)?;
// We seek to the beginning of the file since we expect each file.write_all(&buf).chain_err(|| SEK::FileNotWritten)
// access to the file to be in a different context
f.seek(SeekFrom::Start(0))
.chain_err(|| SEK::FileNotCreated)?;
f.set_len(buf.len() as u64).chain_err(|| SEK::FileNotWritten)?;
f.write_all(&buf).chain_err(|| SEK::FileNotWritten)
},
FSFileAbstractionInstance::Absent(ref p) =>
(create_file(p).chain_err(|| SEK::FileNotCreated)?, p.clone()),
};
*self = FSFileAbstractionInstance::File(file, path);
if let FSFileAbstractionInstance::File(ref mut f, _) = *self {
trace!("Writing buffer...");
return f.write_all(&buf).chain_err(|| SEK::FileNotWritten);
}
unreachable!();
} }
} }
@ -149,7 +116,7 @@ impl FileAbstraction for FSFileAbstraction {
} }
fn new_instance(&self, p: PathBuf) -> Box<FileAbstractionInstance> { fn new_instance(&self, p: PathBuf) -> Box<FileAbstractionInstance> {
Box::new(FSFileAbstractionInstance::Absent(p)) Box::new(FSFileAbstractionInstance(p))
} }
/// We return nothing from the FS here. /// We return nothing from the FS here.