rust-bitcoin-unsafe-fast/src/macros.rs

88 lines
2.5 KiB
Rust

// Rust Bitcoin Library
// Written in 2014 by
// Andrew Poelstra <apoelstra@wpsoftware.net>
//
// To the extent possible under law, the author(s) have dedicated all
// copyright and related and neighboring rights to this software to
// the public domain worldwide. This software is distributed without
// any warranty.
//
// You should have received a copy of the CC0 Public Domain Dedication
// along with this software.
// If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
//
//! # Macros
//!
//! Macros available to users of the Bitcoin library
#![macro_escape]
#[macro_export]
macro_rules! nu_select(
($($name:pat from $rx:expr => $code:expr),+) => ({
nu_select!{ $($name from $rx using recv => $code),+ }
});
($($name:pat from $rx:expr using $meth:ident => $code:expr),+) => ({
use rustrt::local::Local;
use rustrt::task::Task;
use sync::comm::Packet;
// Is anything already ready to receive? Grab it without waiting.
$(
if (&$rx as &Packet).can_recv() {
let $name = $rx.$meth();
$code
}
)else+
else {
// Start selecting on as many as we need to before getting a bite.
// Keep count of how many, since we need to abort every selection
// that we started.
let mut started_count = 0;
// Restrict lifetime of borrows in `packets`
{
let packets = [ $( &$rx as &Packet, )+ ];
let task: Box<Task> = Local::take();
task.deschedule(packets.len(), |task| {
match packets[started_count].start_selection(task) {
Ok(()) => {
started_count += 1;
Ok(())
}
Err(task) => Err(task)
}
});
}
let mut i = 0;
let ret = $(
// Abort the receivers, stopping at the first ready one to get its data.
if { i += 1; i <= started_count } &&
// If start_selection() failed, abort_selection() will fail too,
// but it still counts as "data available".
($rx.abort_selection() || i == started_count) {
// React to the first
let $name = $rx.$meth();
$code
})else+
else {
fail!("we didn't find the ready receiver, but we should have had one");
};
// At this point, the first i receivers have been aborted. We need to abort the rest:
$(if i > 0 {
i -= 1;
} else {
$rx.abort_selection();
})+
let _ = i; // Shut up `i -= 1 but i is never read` warning
// Return
ret
}
})
)