io-da/query

package query

import "time"

// IteratorResult is the struct returned from iterator queries.
type IteratorResult struct {
    resultCore
    proxy     chan interface{}
    listening chan bool
}

func newIteratorResult(buffer int) *IteratorResult {
    return &IteratorResult{
        resultCore: newResultCore(),
        proxy:      make(chan interface{}, buffer),
        listening:  make(chan bool, 1),
    }
}

//------Provide Data------//

// Yield is used to provide values while they are being processed
func (res *IteratorResult) Yield(data interface{}) {
    res.Handled()
    res.proxy <- data
}

//------Fetch Data------//

// Iterate is used to process the values that are being yielded
func (res *IteratorResult) Iterate() <-chan interface{} {
    res.listening <- true
    return res.proxy
}

//------Internal------//

func (res *IteratorResult) waitListener(timeout time.Duration) bool {
    select {
    case <-res.listening:
        return true
    default:
        t := time.NewTimer(timeout)
        select {
        case <-res.listening:
            t.Stop()
            return true
        case <-t.C:
            return false
        }
    }
}

func (res *IteratorResult) close() {
    close(res.proxy)
}