71 lines
2.0 KiB
Rust
71 lines
2.0 KiB
Rust
|
use std::fs::{File, OpenOptions};
|
||
|
|
use std::io::{Read, Write};
|
||
|
|
use std::path::Path;
|
||
|
|
use std::sync::Arc;
|
||
|
|
|
||
|
|
use anyhow::{Context, Result};
|
||
|
|
use bytes::{Buf, BufMut, Bytes};
|
||
|
|
use crossbeam_skiplist::SkipMap;
|
||
|
|
use parking_lot::Mutex;
|
||
|
|
|
||
|
|
pub struct Wal {
|
||
|
|
file: Arc<Mutex<File>>,
|
||
|
|
}
|
||
|
|
|
||
|
|
impl Wal {
|
||
|
|
pub fn create(path: impl AsRef<Path>) -> Result<Self> {
|
||
|
|
Ok(Self {
|
||
|
|
file: Arc::new(Mutex::new(
|
||
|
|
OpenOptions::new()
|
||
|
|
.read(true)
|
||
|
|
.create_new(true)
|
||
|
|
.write(true)
|
||
|
|
.open(path)
|
||
|
|
.context("failed to create WAL")?,
|
||
|
|
)),
|
||
|
|
})
|
||
|
|
}
|
||
|
|
|
||
|
|
pub fn recover(path: impl AsRef<Path>, skiplist: &SkipMap<Bytes, Bytes>) -> Result<Self> {
|
||
|
|
let path = path.as_ref();
|
||
|
|
let mut file = OpenOptions::new()
|
||
|
|
.read(true)
|
||
|
|
.append(true)
|
||
|
|
.open(path)
|
||
|
|
.context("failed to recover from WAL")?;
|
||
|
|
let mut buf = Vec::new();
|
||
|
|
file.read_to_end(&mut buf)?;
|
||
|
|
let mut rbuf: &[u8] = buf.as_slice();
|
||
|
|
while rbuf.has_remaining() {
|
||
|
|
let key_len = rbuf.get_u16() as usize;
|
||
|
|
let key = Bytes::copy_from_slice(&rbuf[..key_len]);
|
||
|
|
rbuf.advance(key_len);
|
||
|
|
let value_len = rbuf.get_u16() as usize;
|
||
|
|
let value = Bytes::copy_from_slice(&rbuf[..value_len]);
|
||
|
|
rbuf.advance(value_len);
|
||
|
|
skiplist.insert(key, value);
|
||
|
|
}
|
||
|
|
Ok(Self {
|
||
|
|
file: Arc::new(Mutex::new(file)),
|
||
|
|
})
|
||
|
|
}
|
||
|
|
|
||
|
|
pub fn put(&self, key: &[u8], value: &[u8]) -> Result<()> {
|
||
|
|
let mut file = self.file.lock();
|
||
|
|
let mut buf: Vec<u8> =
|
||
|
|
Vec::with_capacity(key.len() + value.len() + std::mem::size_of::<u16>());
|
||
|
|
buf.put_u16(key.len() as u16);
|
||
|
|
buf.put_slice(key);
|
||
|
|
buf.put_u16(value.len() as u16);
|
||
|
|
buf.put_slice(value);
|
||
|
|
file.write_all(&buf)?;
|
||
|
|
Ok(())
|
||
|
|
}
|
||
|
|
|
||
|
|
pub fn sync(&self) -> Result<()> {
|
||
|
|
let file = self.file.lock();
|
||
|
|
file.sync_all()?;
|
||
|
|
Ok(())
|
||
|
|
}
|
||
|
|
}
|