use core::{mem, str}; use arch::interrupt::irq::{ACKS, COUNTS, acknowledge}; use syscall::error::*; use syscall::scheme::Scheme; pub struct IrqScheme; impl Scheme for IrqScheme { fn open(&self, path: &[u8], _flags: usize) -> Result<usize> { let path_str = str::from_utf8(path).or(Err(Error::new(ENOENT)))?; let id = path_str.parse::<usize>().or(Err(Error::new(ENOENT)))?; if id < COUNTS.lock().len() { Ok(id) } else { Err(Error::new(ENOENT)) } } fn dup(&self, file: usize) -> Result<usize> { Ok(file) } fn read(&self, file: usize, buffer: &mut [u8]) -> Result<usize> { // Ensures that the length of the buffer is larger than the size of a usize if buffer.len() >= mem::size_of::<usize>() { let ack = ACKS.lock()[file]; let current = COUNTS.lock()[file]; if ack != current { // Safe if the length of the buffer is larger than the size of a usize assert!(buffer.len() >= mem::size_of::<usize>()); unsafe { *(buffer.as_mut_ptr() as *mut usize) = current; } Ok(mem::size_of::<usize>()) } else { Ok(0) } } else { Err(Error::new(EINVAL)) } } fn write(&self, file: usize, buffer: &[u8]) -> Result<usize> { if buffer.len() >= mem::size_of::<usize>() { assert!(buffer.len() >= mem::size_of::<usize>()); let ack = unsafe { *(buffer.as_ptr() as *const usize) }; let current = COUNTS.lock()[file]; if ack == current { ACKS.lock()[file] = ack; unsafe { acknowledge(file); } Ok(mem::size_of::<usize>()) } else { Ok(0) } } else { Err(Error::new(EINVAL)) } } fn fsync(&self, _file: usize) -> Result<usize> { Ok(0) } fn close(&self, _file: usize) -> Result<usize> { Ok(0) } }