rpc/client/request_state.go

package client

import (
	"sync"
	"sync/atomic"
	"time"
)

var zeroTime time.Time

type RequestState struct {
	ID       uint64
	Method   string
	Args     interface{}
	Result   interface{}
	Error    error
	DoneChan chan *RequestState

	hasResponse bool
	canceled    uint32
}

func (rs *RequestState) Done() {
	select {
	case rs.DoneChan <- rs:
		// ok
	default:
		// We don't want to block here. It is the caller's responsibility to make
		// sure the channel has enough buffer space. See comment in Go().
		// if debugLog {
		// 	log.Println("rpc: discarding Call reply due to insufficient Done chan capacity")
		// }
	}
}

// Cancel cancels async call.
//
// Canceled call isn't sent to the server unless it is already sent there.
// Canceled call may successfully complete if it has been already sent
// to the server before Cancel call.
//
// It is safe calling this function multiple times from concurrently
// running goroutines.
func (rs *RequestState) Cancel() {
	atomic.StoreUint32(&rs.canceled, 1)
}

func (rs *RequestState) IsCanceled() bool {
	return atomic.LoadUint32(&rs.canceled) != 0
}

var requestStatePool sync.Pool

func retainRequestState() *RequestState {
	v := requestStatePool.Get()
	if v == nil {
		return &RequestState{}
	}
	return v.(*RequestState)
}

func releaseCallState(rs *RequestState) {
	rs.Method = ""
	rs.Args = nil
	rs.Result = nil
	rs.Error = nil
	rs.DoneChan = nil

	requestStatePool.Put(rs)
}