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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Waiting for FDs via epoll(7).
package net
import (
"net";
"os";
"syscall";
)
const (
Read = syscall.EPOLLIN | syscall.EPOLLRDHUP;
Write = syscall.EPOLLOUT
)
export type Pollster struct {
epfd int64;
// Events we're already waiting for
events map[int64] uint32;
}
export func NewPollster() (p *Pollster, err *os.Error) {
p = new(Pollster);
var e int64;
// The arg to epoll_create is a hint to the kernel
// about the number of FDs we will care about.
// We don't know.
if p.epfd, e = syscall.epoll_create(16); e != 0 {
return nil, os.ErrnoToError(e)
}
p.events = make(map[int64] uint32);
return p, nil
}
func (p *Pollster) AddFD(fd int64, mode int, repeat bool) *os.Error {
var ev syscall.EpollEvent;
var already bool;
ev.fd = int32(fd);
ev.events, already = p.events[fd];
if !repeat {
ev.events |= syscall.EPOLLONESHOT
}
if mode == 'r' {
ev.events |= Read
} else {
ev.events |= Write
}
var op int64;
if already {
op = syscall.EPOLL_CTL_MOD
} else {
op = syscall.EPOLL_CTL_ADD
}
if e := syscall.epoll_ctl(p.epfd, op, fd, &ev); e != 0 {
return os.ErrnoToError(e)
}
p.events[fd] = ev.events;
return nil
}
func (p *Pollster) StopWaiting(fd int64, bits uint) {
events, already := p.events[fd];
if !already {
print("Epoll unexpected fd=", fd, "\n");
return
}
// If syscall.EPOLLONESHOT is not set, the wait
// is a repeating wait, so don't change it.
if events & syscall.EPOLLONESHOT == 0 {
return
}
// Disable the given bits.
// If we're still waiting for other events, modify the fd
// event in the kernel. Otherwise, delete it.
events &= ^uint32(bits);
if int32(events) & ^syscall.EPOLLONESHOT != 0 {
var ev syscall.EpollEvent;
ev.fd = int32(fd);
ev.events = events;
if e := syscall.epoll_ctl(p.epfd, syscall.EPOLL_CTL_MOD, fd, &ev); e != 0 {
print("Epoll modify fd=", fd, ": ", os.ErrnoToError(e).String(), "\n")
}
p.events[fd] = events
} else {
if e := syscall.epoll_ctl(p.epfd, syscall.EPOLL_CTL_DEL, fd, nil); e != 0 {
print("Epoll delete fd=", fd, ": ", os.ErrnoToError(e).String(), "\n")
}
p.events[fd] = 0, false
}
}
func (p *Pollster) WaitFD() (fd int64, mode int, err *os.Error) {
// Get an event.
var evarray [1]syscall.EpollEvent;
ev := &evarray[0];
n, e := syscall.epoll_wait(p.epfd, evarray, -1);
for e == syscall.EAGAIN || e == syscall.EINTR {
n, e = syscall.epoll_wait(p.epfd, evarray, -1)
}
if e != 0 {
return -1, 0, os.ErrnoToError(e)
}
fd = int64(ev.fd);
if ev.events & Write != 0 {
p.StopWaiting(fd, Write);
return fd, 'w', nil
}
if ev.events & Read != 0 {
p.StopWaiting(fd, Read);
return fd, 'r', nil
}
// Other events are error conditions - wake whoever is waiting.
events, already := p.events[fd];
if events & Write != 0 {
p.StopWaiting(fd, Write);
return fd, 'w', nil
}
p.StopWaiting(fd, Read);
return fd, 'r', nil
}
func (p *Pollster) Close() *os.Error {
r, e := syscall.close(p.epfd);
return os.ErrnoToError(e)
}
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