/
first.go
46 lines (41 loc) · 995 Bytes
/
first.go
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package google
import (
"errors"
"time"
)
func First(replicas ...SearchFunc) SearchFunc { // HL
return func(query string) Result {
c := make(chan Result, len(replicas))
searchReplica := func(i int) {
c <- replicas[i](query)
}
for i := range replicas {
go searchReplica(i) // HL
}
return <-c
}
}
// START OMIT
var (
replicatedWeb = First(Web1, Web2) // HL
replicatedImage = First(Image1, Image2) // HL
replicatedVideo = First(Video1, Video2) // HL
)
func SearchReplicated(query string, timeout time.Duration) ([]Result, error) {
timer := time.After(timeout)
c := make(chan Result, 3)
go func() { c <- replicatedWeb(query) }() // HL
go func() { c <- replicatedImage(query) }() // HL
go func() { c <- replicatedVideo(query) }() // HL
// STOP OMIT
var results []Result
for i := 0; i < 3; i++ {
select {
case result := <-c:
results = append(results, result)
case <-timer:
return results, errors.New("timed out")
}
}
return results, nil
}