path: root/examples/demo1.rs

use std::os::unix::io::RawFd;
use nix::unistd::{close, mkdir, unlinkat, UnlinkatFlags, ftruncate};
use nix::fcntl::{open, openat, OFlag, fallocate, FallocateFlags};
use nix::sys::{stat::Mode, uio::{pwrite, pread}};
use rand::{Rng, seq::SliceRandom};
use libc::off_t;

use growthring::wal::{WALFile, WALStore, WALPos, WALBytes, WALLoader, WALWriter, WALRingId};

struct WALFileTest {
    filename: String,
    fd: RawFd,
}

impl WALFileTest {
    fn new(rootfd: RawFd, filename: &str) -> Result<Self, ()> {
        openat(rootfd, filename,
            OFlag::O_CREAT | OFlag::O_RDWR,
            Mode::S_IRUSR | Mode::S_IWUSR).and_then(|fd| {
            let filename = filename.to_string();
            Ok (WALFileTest {
                filename,
                fd,
            })
        }).or_else(|_| Err(()))
    }
}

impl Drop for WALFileTest {
    fn drop(&mut self) {
        close(self.fd).unwrap();
    }
}

impl WALFile for WALFileTest {
    fn allocate(&self, offset: WALPos, length: usize) -> Result<(), ()> {
        println!("{}.allocate(offset=0x{:x}, end=0x{:x})", self.filename, offset, offset + length as u64);
        fallocate(self.fd,
                FallocateFlags::FALLOC_FL_ZERO_RANGE,
                offset as off_t, length as off_t).and_then(|_| Ok(())).or_else(|_| Err(()))
    }

    fn truncate(&self, length: usize) -> Result<(), ()> {
        println!("{}.truncate(length={})", self.filename, length);
        ftruncate(self.fd, length as off_t).or_else(|_| Err(()))
    }

    fn write(&self, offset: WALPos, data: WALBytes) -> Result<(), ()> {
        println!("{}.write(offset=0x{:x}, end=0x{:x}, data=0x{})",
                self.filename, offset, offset + data.len() as u64, hex::encode(&data));
        pwrite(self.fd, &*data, offset as off_t)
            .or_else(|_| Err(()))
            .and_then(|nwrote| if nwrote == data.len() { Ok(()) } else { Err(()) })
    }

    fn read(&self, offset: WALPos, length: usize) -> Result<Option<WALBytes>,