Trait LuaFileHandle 

pub trait LuaFileHandle: Send {
    // Required methods
    fn read_byte(&mut self) -> i32;
    fn unread_byte(&mut self, byte: i32);
    fn write_bytes(&mut self, data: &[u8]) -> Result<usize>;
    fn flush(&mut self) -> Result<()>;
    fn seek(&mut self, pos: SeekFrom) -> Result<u64>;
    fn tell(&mut self) -> Result<u64>;
    fn clear_error(&mut self);
    fn has_error(&self) -> bool;

    // Provided methods
    fn last_error_info(&self) -> Option<(i32, String)> { ... }
    fn set_buf_mode(&mut self, _mode: i32, _size: usize) -> Result<()> { ... }
}

Capabilities required by the io library from an OS file handle.

Designed to be object-safe (Box<dyn LuaFileHandle>). Implementations backed by std::fs::File live in lua-cli; implementations for the standard streams live in lua-stdlib/src/io_lib.rs.

Required Methods

fn read_byte(&mut self) -> i32

Read one byte from the handle; return it as i32, or -1 on EOF/error.

fn unread_byte(&mut self, byte: i32)

Push back a previously-read byte so the next read_byte returns it.

fn write_bytes(&mut self, data: &[u8]) -> Result<usize>

Write a byte slice; return the number of bytes actually written.

fn flush(&mut self) -> Result<()>

Flush any write buffers to the underlying OS handle.

fn seek(&mut self, pos: SeekFrom) -> Result<u64>

Seek within the file.

fn tell(&mut self) -> Result<u64>

Return the current file position without moving it.

fn clear_error(&mut self)

Clear the error/EOF flag on the handle.

fn has_error(&self) -> bool

Return true if the handle has a pending error.

Provided Methods

fn last_error_info(&self) -> Option<(i32, String)>

Return the last pending OS error as (errno, message) when available.

Some real Lua programs probe platform behavior through specific errno values. LuaRocks’ macOS directory detection, for example, expects reading an opened directory to report EISDIR rather than look like EOF.

fn set_buf_mode(&mut self, _mode: i32, _size: usize) -> Result<()>

Control write buffering. Mode values mirror file:setvbuf option order: 0 = no buffering, 1 = full buffering, 2 = line buffering.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors