fd_poll_runtime.go

package gotfo

import (
	"errors"
	"time"
)

func (pd *pollDesc) close() {
	if pd.runtimeCtx == 0 {
		return
	}
	runtime_pollClose(pd.runtimeCtx)
	pd.runtimeCtx = 0
}

// Evict evicts fd from the pending list, unblocking any I/O running on fd.
func (pd *pollDesc) evict() {
	if pd.runtimeCtx == 0 {
		return
	}
	runtime_pollUnblock(pd.runtimeCtx)
}

func (pd *pollDesc) prepare(mode int) error {
	if pd.runtimeCtx == 0 {
		return nil
	}
	res := runtime_pollReset(pd.runtimeCtx, mode)
	return convertErr(res)
}

func (pd *pollDesc) prepareRead(isFile bool) error {
	return pd.prepare('r')
}

func (pd *pollDesc) prepareWrite(isFile bool) error {
	return pd.prepare('w')
}

func (pd *pollDesc) wait(mode int) error {
	if pd.runtimeCtx == 0 {
		return errors.New("waiting for unsupported file type")
	}
	res := runtime_pollWait(pd.runtimeCtx, mode)
	return convertErr(res)
}

func (pd *pollDesc) waitRead() error {
	return pd.wait('r')
}

func (pd *pollDesc) waitWrite() error {
	return pd.wait('w')
}

func (pd *pollDesc) waitCanceled(mode int) {
	if pd.runtimeCtx == 0 {
		return
	}
	runtime_pollWaitCanceled(pd.runtimeCtx, mode)
}

func (pd *pollDesc) pollable() bool {
	return pd.runtimeCtx != 0
}

func convertErr(res int) error {
	switch res {
	case 0:
		return nil
	case 1:
		return errClosing
	case 2:
		return errTimeout
	}
	println("unreachable: ", res)
	panic("unreachable")
}

// SetDeadline sets the read and write deadlines associated with fd.
func (fd *netFD) SetDeadline(t time.Time) error {
	return setDeadlineImpl(fd, t, 'r'+'w')
}

// SetReadDeadline sets the read deadline associated with fd.
func (fd *netFD) SetReadDeadline(t time.Time) error {
	return setDeadlineImpl(fd, t, 'r')
}

// SetWriteDeadline sets the write deadline associated with fd.
func (fd *netFD) SetWriteDeadline(t time.Time) error {
	return setDeadlineImpl(fd, t, 'w')
}

func setDeadlineImpl(fd *netFD, t time.Time, mode int) error {
	diff := int64(time.Until(t))
	d := runtimeNano() + diff
	if d <= 0 && diff > 0 {
		// If the user has a deadline in the future, but the delay calculation
		// overflows, then set the deadline to the maximum possible value.
		d = 1<<63 - 1
	}
	if t.IsZero() {
		d = 0
	}
	if err := fd.incref(); err != nil {
		return err
	}

	// https://github.com/golang/go/commit/3813f941f6ff80f64d14db35f8b6446e10e45411#diff-2fac41fb57b6d5728ad14f6115f7219b
	defer fd.decref()
	if fd.pd.runtimeCtx == 0 {
		return errors.New("file type does not support deadlines")
	}
	runtime_pollSetDeadline(fd.pd.runtimeCtx, d, mode)
	return nil
}