//! Independent read-only handle offsets and transactional seek refusal.

use super::*;
use os_vfs_lookup::{LookupTable, Mount};
use os_vfs_open::{OpenFlags, OpenTable};
use os_vfs_offset::{CursorTable, Error as OffsetError, Whence};

pub fn run(allocator: &mut memory::FrameAllocator) -> Result<(), &'static str> {
    let frames_before = allocator.remaining_pages();
    let first_mount = Mount::new(1, 11, b"dosya").map_err(|_| "k1570-first")?;
    let second_mount = Mount::new(2, 22, b"dosya").map_err(|_| "k1570-second")?;
    let lookup = LookupTable::new(first_mount, second_mount)
        .map_err(|_| "k1570-lookup")?;
    let dentry = lookup.lookup(1, b"dosya").map_err(|_| "k1570-dentry")?;
    let mut opens = OpenTable::new();
    let first = opens.open(&lookup, dentry, OpenFlags::READ_ONLY)
        .map_err(|_| "k1570-open-one")?;
    let second = opens.open(&lookup, dentry, OpenFlags::READ_ONLY)
        .map_err(|_| "k1570-open-two")?;
    let mut cursors = CursorTable::new();
    cursors.attach(first).map_err(|_| "k1570-attach-one")?;
    cursors.attach(second).map_err(|_| "k1570-attach-two")?;
    if cursors.read_complete(first.id, 8, 3) != Ok(3)
        || cursors.seek(first.id, Whence::Current, 4, 10) != Ok(7)
        || cursors.offset(second.id) != Ok(0) {
        return Err("k1570-short-read");
    }
    let before = cursors;
    if cursors.seek(first.id, Whence::Start, -1, 10)
        != Err(OffsetError::NegativeSeek)
        || cursors.seek(first.id, Whence::End, 1, u64::MAX)
            != Err(OffsetError::Overflow)
        || cursors != before {
        return Err("k1570-rejected-seek");
    }
    if cursors.seek(second.id, Whence::Start, 5, 10) != Ok(5)
        || cursors.offset(first.id) != Ok(7)
        || allocator.remaining_pages() != frames_before {
        return Err("k1570-other-handle");
    }
    opens.close(first).map_err(|_| "k1570-close-one")?;
    opens.close(second).map_err(|_| "k1570-close-two")?;
    write_line("TURKOS/OS/K1570-OFFSET: SHORT=3 SEEK=7 NEG=REJECTED OVERFLOW=REJECTED OTHER=5 FRAMES=UNCHANGED");
    Ok(())
}