Function pwrite_all

nodedb-wal/src/double_write.rs:443–475

`pwrite`-retry helper that handles short writes.

(file: &File, data: &[u8], offset: u64)

/// `pwrite`-retry helper that handles short writes.
fn pwrite_all(file: &File, data: &[u8], offset: u64) -> Result<()> {
    #[cfg(not(target_arch = "wasm32"))]
    {
        use std::os::unix::io::AsRawFd as _;
        let fd = file.as_raw_fd();
        let mut remaining = data;
        let mut write_offset = offset;
        while !remaining.is_empty() {
            let n = unsafe {
                libc::pwrite(
                    fd,
                    remaining.as_ptr() as *const libc::c_void,
                    remaining.len(),
                    write_offset as libc::off_t,
                )
            };
            if n < 0 {
                return Err(WalError::Io(std::io::Error::last_os_error()));
            }
            let n = n as usize;
            remaining = &remaining[n..];
            write_offset += n as u64;
        }
        Ok(())
    }
    #[cfg(target_arch = "wasm32")]
    {
        let _ = (file, data, offset);
        Err(WalError::Unsupported {
            detail: "O_DIRECT pwrite not available on wasm32",
        })
    }
}

#[cfg(test)]
mod tests {