Golang syscall.CancelIo函數代碼示例

func timeoutIO() {
	// CancelIO only cancels all pending input and output (I/O) operations that are
	// issued by the calling thread for the specified file, does not cancel I/O
	// operations that other threads issue for a file handle. So we need do all timeout
	// I/O in single OS thread.
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()
	for {
		o := <-ioChan
		var e int
		switch o.f {
		case read:
			e = syscall.WSARecv(uint32(o.fd.sysfd), o.pckt.w, 1, o.done, o.flags, &o.pckt.o, nil)
		case readfrom:
			e = syscall.WSARecvFrom(uint32(o.fd.sysfd), o.pckt.w, 1, o.done, o.flags, o.rsa, o.size, &o.pckt.o, nil)
		case write:
			e = syscall.WSASend(uint32(o.fd.sysfd), o.pckt.w, 1, o.done, uint32(0), &o.pckt.o, nil)
		case writeto:
			e = syscall.WSASendto(uint32(o.fd.sysfd), o.pckt.w, 1, o.done, 0, *o.sa, &o.pckt.o, nil)
		case cancel:
			_, e = syscall.CancelIo(uint32(o.fd.sysfd))
		}
		o.c <- e
	}
}

// Must run within the I/O thread.
func (w *Watcher) startRead(watch *watch) error {
	if e := syscall.CancelIo(watch.ino.handle); e != nil {
		w.Error <- os.NewSyscallError("CancelIo", e)
		w.deleteWatch(watch)
	}
	mask := toWindowsFlags(watch.mask)
	for _, m := range watch.names {
		mask |= toWindowsFlags(m)
	}
	if mask == 0 {
		if e := syscall.CloseHandle(watch.ino.handle); e != nil {
			w.Error <- os.NewSyscallError("CloseHandle", e)
		}
		delete(w.watches[watch.ino.volume], watch.ino.index)
		return nil
	}
	e := syscall.ReadDirectoryChanges(watch.ino.handle, &watch.buf[0],
		uint32(unsafe.Sizeof(watch.buf)), false, mask, nil, &watch.ov, 0)
	if e != nil {
		err := os.NewSyscallError("ReadDirectoryChanges", e)
		if e == syscall.ERROR_ACCESS_DENIED && watch.mask&provisional == 0 {
			// Watched directory was probably removed
			if w.sendEvent(watch.path, watch.mask&FS_DELETE_SELF) {
				if watch.mask&FS_ONESHOT != 0 {
					watch.mask = 0
				}
			}
			err = nil
		}
		w.deleteWatch(watch)
		w.startRead(watch)
		return err
	}
	return nil
}

// ProcessRemoteIO will execute submit IO requests on behalf
// of other goroutines, all on a single os thread, so it can
// cancel them later. Results of all operations will be sent
// back to their requesters via channel supplied in request.
// It is used only when the CancelIoEx API is unavailable.
func (s *ioSrv) ProcessRemoteIO() {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()
	for r := range s.req {
		if r.submit != nil {
			r.o.errc <- r.submit(r.o)
		} else {
			r.o.errc <- syscall.CancelIo(r.o.fd.sysfd)
		}
	}
}

// ProcessRemoteIO will execute submit IO requests on behalf
// of other goroutines, all on a single os thread, so it can
// cancel them later. Results of all operations will be sent
// back to their requesters via channel supplied in request.
// It is used only when the CancelIoEx API is unavailable.
func (s *ioSrv) ProcessRemoteIO() {
	runtime.LockOSThread()
	defer runtime.UnlockOSThread()
	for {
		select {
		case o := <-s.submchan:
			o.Op().errnoc <- o.Submit()
		case o := <-s.canchan:
			o.Op().errnoc <- syscall.CancelIo(syscall.Handle(o.Op().fd.sysfd))
		}
	}
}