168 lines
4 KiB
Go
168 lines
4 KiB
Go
// Copyright 2013 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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//go:build aix || darwin || dragonfly || freebsd || hurd || linux || netbsd || openbsd || windows || solaris
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package poll
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import (
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"errors"
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"sync"
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"syscall"
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"time"
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_ "unsafe" // for go:linkname
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)
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// runtimeNano returns the current value of the runtime clock in nanoseconds.
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//go:linkname runtimeNano runtime.nanotime
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func runtimeNano() int64
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func runtime_pollServerInit()
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func runtime_pollOpen(fd uintptr) (uintptr, int)
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func runtime_pollClose(ctx uintptr)
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func runtime_pollWait(ctx uintptr, mode int) int
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func runtime_pollWaitCanceled(ctx uintptr, mode int) int
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func runtime_pollReset(ctx uintptr, mode int) int
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func runtime_pollSetDeadline(ctx uintptr, d int64, mode int)
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func runtime_pollUnblock(ctx uintptr)
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func runtime_isPollServerDescriptor(fd uintptr) bool
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type pollDesc struct {
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runtimeCtx uintptr
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}
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var serverInit sync.Once
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func (pd *pollDesc) init(fd *FD) error {
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serverInit.Do(runtime_pollServerInit)
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ctx, errno := runtime_pollOpen(uintptr(fd.Sysfd))
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if errno != 0 {
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return errnoErr(syscall.Errno(errno))
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}
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pd.runtimeCtx = ctx
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return nil
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}
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func (pd *pollDesc) close() {
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if pd.runtimeCtx == 0 {
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return
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}
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runtime_pollClose(pd.runtimeCtx)
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pd.runtimeCtx = 0
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}
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// Evict evicts fd from the pending list, unblocking any I/O running on fd.
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func (pd *pollDesc) evict() {
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if pd.runtimeCtx == 0 {
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return
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}
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runtime_pollUnblock(pd.runtimeCtx)
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}
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func (pd *pollDesc) prepare(mode int, isFile bool) error {
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if pd.runtimeCtx == 0 {
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return nil
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}
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res := runtime_pollReset(pd.runtimeCtx, mode)
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return convertErr(res, isFile)
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}
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func (pd *pollDesc) prepareRead(isFile bool) error {
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return pd.prepare('r', isFile)
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}
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func (pd *pollDesc) prepareWrite(isFile bool) error {
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return pd.prepare('w', isFile)
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}
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func (pd *pollDesc) wait(mode int, isFile bool) error {
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if pd.runtimeCtx == 0 {
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return errors.New("waiting for unsupported file type")
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}
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res := runtime_pollWait(pd.runtimeCtx, mode)
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return convertErr(res, isFile)
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}
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func (pd *pollDesc) waitRead(isFile bool) error {
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return pd.wait('r', isFile)
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}
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func (pd *pollDesc) waitWrite(isFile bool) error {
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return pd.wait('w', isFile)
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}
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func (pd *pollDesc) waitCanceled(mode int) {
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if pd.runtimeCtx == 0 {
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return
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}
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runtime_pollWaitCanceled(pd.runtimeCtx, mode)
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}
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func (pd *pollDesc) pollable() bool {
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return pd.runtimeCtx != 0
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}
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// Error values returned by runtime_pollReset and runtime_pollWait.
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// These must match the values in runtime/netpoll.go.
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const (
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pollNoError = 0
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pollErrClosing = 1
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pollErrTimeout = 2
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pollErrNotPollable = 3
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)
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func convertErr(res int, isFile bool) error {
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switch res {
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case pollNoError:
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return nil
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case pollErrClosing:
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return errClosing(isFile)
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case pollErrTimeout:
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return ErrDeadlineExceeded
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case pollErrNotPollable:
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return ErrNotPollable
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}
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println("unreachable: ", res)
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panic("unreachable")
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}
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// SetDeadline sets the read and write deadlines associated with fd.
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func (fd *FD) SetDeadline(t time.Time) error {
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return setDeadlineImpl(fd, t, 'r'+'w')
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}
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// SetReadDeadline sets the read deadline associated with fd.
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func (fd *FD) SetReadDeadline(t time.Time) error {
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return setDeadlineImpl(fd, t, 'r')
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}
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// SetWriteDeadline sets the write deadline associated with fd.
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func (fd *FD) SetWriteDeadline(t time.Time) error {
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return setDeadlineImpl(fd, t, 'w')
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}
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func setDeadlineImpl(fd *FD, t time.Time, mode int) error {
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var d int64
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if !t.IsZero() {
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d = int64(time.Until(t))
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if d == 0 {
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d = -1 // don't confuse deadline right now with no deadline
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}
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}
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if err := fd.incref(); err != nil {
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return err
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}
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defer fd.decref()
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if fd.pd.runtimeCtx == 0 {
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return ErrNoDeadline
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}
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runtime_pollSetDeadline(fd.pd.runtimeCtx, d, mode)
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return nil
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}
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// IsPollDescriptor reports whether fd is the descriptor being used by the poller.
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// This is only used for testing.
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func IsPollDescriptor(fd uintptr) bool {
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return runtime_isPollServerDescriptor(fd)
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}
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