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use std::io::{Read, Seek, Write};
use std::sync::Arc;
use std::sync::atomic::AtomicBool;
#[cfg(feature = "libc")]
#[cfg(target_os = "linux")]
use libc::{FALLOC_FL_KEEP_SIZE, FALLOC_FL_PUNCH_HOLE, fallocate};
#[cfg(feature = "zstd")]
use zstd::block::decompress;
use super::*;
pub struct LockFreeLog {
pub(super) iobufs: Arc<IoBufs>,
flusher_shutdown: Arc<AtomicBool>,
flusher_handle: Option<std::thread::JoinHandle<()>>,
}
unsafe impl Send for LockFreeLog {}
unsafe impl Sync for LockFreeLog {}
impl Drop for LockFreeLog {
fn drop(&mut self) {
self.flusher_shutdown.store(
true,
std::sync::atomic::Ordering::SeqCst,
);
if let Some(join_handle) = self.flusher_handle.take() {
join_handle.join().unwrap();
}
}
}
impl LockFreeLog {
pub fn start_system(config: Config) -> LockFreeLog {
let iobufs = Arc::new(IoBufs::new(config.clone()));
let flusher_shutdown = Arc::new(AtomicBool::new(false));
let flusher_handle = config.get_flush_every_ms().map(|flush_every_ms| {
periodic_flusher::flusher(
"log flusher".to_owned(),
iobufs.clone(),
flusher_shutdown.clone(),
flush_every_ms,
).unwrap()
});
LockFreeLog {
iobufs: iobufs,
flusher_shutdown: flusher_shutdown,
flusher_handle: flusher_handle,
}
}
pub fn flush(&self) {
self.iobufs.flush();
}
}
impl Log for LockFreeLog {
fn reserve(&self, buf: Vec<u8>) -> Reservation {
self.iobufs.reserve(buf)
}
fn config(&self) -> &Config {
self.iobufs.config()
}
fn write(&self, buf: Vec<u8>) -> LogID {
self.iobufs.reserve(buf).complete()
}
fn read(&self, id: LogID) -> io::Result<LogRead> {
let cached_f = self.config().cached_file();
let mut f = cached_f.borrow_mut();
f.seek(SeekFrom::Start(id))?;
let mut valid = [0u8; 1];
f.read_exact(&mut valid)?;
let mut len_buf = [0u8; 4];
f.read_exact(&mut len_buf)?;
let len32: u32 = unsafe { std::mem::transmute(len_buf) };
let len = len32 as usize;
let max = self.config().get_io_buf_size() - HEADER_LEN;
if len > max {
#[cfg(feature = "log")]
error!("log read invalid message length, {} should be <= {}", len, max);
return Ok(LogRead::Corrupted(len));
}
if valid[0] == 0 {
return Ok(LogRead::Aborted(len));
}
let mut crc16_buf = [0u8; 2];
f.read_exact(&mut crc16_buf)?;
let mut buf = Vec::with_capacity(len);
unsafe {
buf.set_len(len);
}
f.read_exact(&mut buf)?;
let checksum = crc16_arr(&buf);
if checksum != crc16_buf {
return Ok(LogRead::Corrupted(len));
}
#[cfg(feature = "zstd")]
{
if self.config().get_use_compression() {
Ok(LogRead::Flush(decompress(&*buf, max).unwrap(), len))
} else {
Ok(LogRead::Flush(buf, len))
}
}
#[cfg(not(feature = "zstd"))] Ok(LogRead::Flush(buf, len))
}
fn stable_offset(&self) -> LogID {
self.iobufs.stable()
}
fn make_stable(&self, id: LogID) {
let mut spins = 0;
loop {
self.iobufs.flush();
spins += 1;
if spins > 2_000_000 {
#[cfg(feature = "log")]
debug!("have spun >2000000x in make_stable");
spins = 0;
}
let cur = self.iobufs.stable();
if cur > id {
return;
}
}
}
fn punch_hole(&self, id: LogID) {
let cached_f = self.config().cached_file();
let mut f = cached_f.borrow_mut();
f.seek(SeekFrom::Start(id)).unwrap();
let zeros = vec![0];
f.write_all(&*zeros).unwrap();
f.seek(SeekFrom::Start(id + 1)).unwrap();
let mut len_buf = [0u8; 4];
f.read_exact(&mut len_buf).unwrap();
#[cfg(feature = "libc")]
#[cfg(target_os = "linux")]
{
use std::os::unix::io::AsRawFd;
let len32: u32 = unsafe { std::mem::transmute(len_buf) };
let len = len32 as usize;
let mode = FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE;
let fd = f.as_raw_fd();
unsafe {
fallocate(fd, mode, id as i64 + 5, len as i64 + 2);
}
}
}
}