Function handle_file_readonly

euralios_std/src/server.rs:264–306

Serve messages received from a communication channel Only allow reading from the file

(file: Arc<RwLock<dyn FileLike + Sync + Send>>,
                        comm_handle: CommHandle)

/// Serve messages received from a communication channel
/// Only allow reading from the file
fn handle_file_readonly(file: Arc<RwLock<dyn FileLike + Sync + Send>>,
                        comm_handle: CommHandle) {
    dispatch_loop(
        &comm_handle,
        |msg| {
            match msg {
                syscalls::Message::Short(
                    message::READ, start, length) => {

                    let f = file.read();
                    let len = cmp::min(f.len(), length as usize);

                    if let Err((err, _msg)) = if len == 0 {
                        // No data
                        syscalls::send(&comm_handle,
                                       syscalls::Message::Short(
                                           message::ERROR,
                                           syscalls::SYSCALL_ERROR_NO_DATA.as_u64(), 0))
                    } else {
                        // Allocate memory
                        let (mut mem_handle, _) = malloc(len as u64, 0).unwrap();
                        // Read data
                        match f.read(start as usize, mem_handle.as_mut_slice(len)) {
                            Ok(nbytes) => syscalls::send(&comm_handle,
                                                         syscalls::Message::Long(
                                                             message::DATA,
                                                             (nbytes as u64).into(),
                                                             mem_handle.into())),
                            Err(sys_err) => syscalls::send(&comm_handle,
                                                           syscalls::Message::Short(
                                                               message::ERROR, sys_err.as_u64(), 0))
                        }
                    } {
                        // Failed to send reply
                        println!("[std:handle_file_ro] Reply failed: {}", err);
                    }
                }
                msg => {
                    println!("[std:handle_file_ro] unexpected {:?}", msg);
                }
            }
        });
}

/// Handle messages for a given directory
///