여러 맵 로컬 검색을 동시에 수행

여러 검색을 동기식으로 수행하고 (다음 요청을 실행하기 전에 이전 요청이 완료 될 때까지 기다림) 계속 진행하기 전에 모든 작업이 완료 될 때까지 차단합니다.

그러나 로컬 검색의 완료 핸들은 세마포어가 포기하면 차단 된 것처럼 보이고 실행됩니다. 나는 성공하지 못한 채 많은 시도를했다.

내 코드와 로그는 다음과 같습니다 (플레이 그라운드에 복사 / 붙여 넣기 가능).

import CoreLocation
import MapKit


func search(_ query: String, in span: MKCoordinateSpan, centered center: CLLocationCoordinate2D, id: Int) {

    let semaphore = DispatchSemaphore(value: 0)
    //let group = DispatchGroup(); group.enter()

    // Run the request for this rect
    print("\(#function): local search on the \(id)th portion ")

    let request = MKLocalSearch.Request()
    request.naturalLanguageQuery = query
    request.region = MKCoordinateRegion(center: center, span: span)

    if #available(iOS 13, *) {
        request.resultTypes = .pointOfInterest
    }


    let search = MKLocalSearch(request: request)

    search.start { response, error in
        print("\(id) got \(response?.mapItems.count) items")
        semaphore.signal()
    }


    let s = semaphore
    //let s = group

    // Wait for the request ot complete
    print("\(#function): waiting for the \(id)th portion to complete")
    //guard _ = s.wait(wallTimeout: .distantFuture) else {
    guard s.wait(timeout: .now() + 5) == .success else {
        print("\(#function): ***Warning: \(id)th timeout, job incomplete")
        return
    }

    print("\(#function): \(id)th completed")
}



let rect = CGRect(
    x: 48.10,
    y: 3.43,
    width: 0.09,
    height: 0.09
)


let n = 4
let latDelta = rect.width / CGFloat(n)
var latOffs = rect.minX



let queue = OperationQueue()
//queue.maxConcurrentOperationCount = 1
var ops = [BlockOperation]()

// -- Run all asyn loca search requests synchronuously
for i in 0..<n {
    // Take the next cut of the original region
    let portion = CGRect(
        x: latOffs,
        y: rect.minY,
        width: latDelta,
        height: rect.height
    )

    latOffs += latDelta

    ops.append(BlockOperation { [portion, i] in
        let center = CLLocationCoordinate2D(latitude: CLLocationDegrees(portion.midX), longitude: CLLocationDegrees(portion.midY))
        let span = MKCoordinateSpan(latitudeDelta: CLLocationDegrees(portion.width), longitudeDelta: CLLocationDegrees(portion.height))

        search("coffee", in: span, centered: center, id: i)
    })
}

queue.addOperations(ops, waitUntilFinished: true)

print("All done")

현재 가짜 출력 :

search(_:in:centered:id:): local search on the 1th portion 
search(_:in:centered:id:): local search on the 2th portion 
search(_:in:centered:id:): local search on the 3th portion 
search(_:in:centered:id:): local search on the 0th portion 
search(_:in:centered:id:): waiting for the 1th portion to complete
search(_:in:centered:id:): waiting for the 3th portion to complete
search(_:in:centered:id:): waiting for the 2th portion to complete
search(_:in:centered:id:): waiting for the 0th portion to complete
search(_:in:centered:id:): ***Warning: 0th timeout, job incomplete
search(_:in:centered:id:): ***Warning: 2th timeout, job incomplete
search(_:in:centered:id:): ***Warning: 1th timeout, job incomplete
search(_:in:centered:id:): ***Warning: 3th timeout, job incomplete
All done
0 got Optional(10) items
2 got Optional(10) items
1 got Optional(10) items
3 got Optional(10) items

[최신 정보]

예상되는 출력은 다음과 같이 no ***Warning및 All done마지막 줄로 표시되어야 합니다 (정확한 번호 매기기 순서는 네트워크 조건에 따라 다름).

search(_:in:centered:id:): local search on the 1th portion 
search(_:in:centered:id:): local search on the 2th portion 
search(_:in:centered:id:): local search on the 3th portion 
search(_:in:centered:id:): local search on the 0th portion 
search(_:in:centered:id:): waiting for the 1th portion to complete
search(_:in:centered:id:): waiting for the 3th portion to complete
search(_:in:centered:id:): waiting for the 2th portion to complete
search(_:in:centered:id:): waiting for the 0th portion to complete
0 got Optional(10) items
search(_:in:centered:id:): 0th completed
2 got Optional(10) items
search(_:in:centered:id:): 2th completed
1 got Optional(10) items
search(_:in:centered:id:): 1th completed
3 got Optional(10) items
search(_:in:centered:id:): 3th completed
All done

[업데이트 2] 라인 주석 해제시 출력되는 내용 //queue.maxConcurrentOperationCount = 1

search ( : in : centered : id :) : 0 번째 부분에 대한 지역 검색 2020-03-28 23:49:41 +0000 search ( : in : centered : id :) : 0 번째 부분이 완료되기를 기다립니다 2020-03 -28 23:49:41 +0000 search ( : in : centered : id :) : *** 경고 : 0 번째 타임 아웃, 작업 미완료 2020-03-28 23:49:46 +0000 search ( : in : centered : id :) : 1 차 지역 검색 2020-03-28 23:49:46 +0000 search ( : in : centered : id :) : 1 차 부분 완료 대기 2020-03-28 23:49:46 + 0000 search ( : in : centered : id :) : *** 경고 : 1 차 타임 아웃, 작업 미완료 2020-03-28 23:49:51 +0000 search ( : in : centered : id :) : 2 일 로컬 검색 부분 2020-03-28 23:49:51 +0000 search ( : in : centered : id :) : 2 번째 부분 완료 대기 2020-03-28 23:49:51 +0000 search (: in : centered : id :) : *** 경고 : 2 차 타임 아웃, 작업 미완료 2020-03-28 23:49:56 +0000 search ( : in : centered : id :) : 3 차 부분 로컬 검색 2020- 03-28 23:49:56 +0000 search ( : in : centered : id :) : 3 번째 부분 완료 대기 2020-03-28 23:49:56 +0000 search ( : in : centered : id :) : *** 경고 : 3 번째 타임 아웃, 작업 미완료 2020-03-28 23:50:01 +0000 완료 됨 2020-03-28 23:50:01 +0000 0 개 선택 사항 (10) 항목 획득 2020-03-28 23 : 50 : 02 +0000 3 개 획득 옵션 (10) 개 2020-03-28 23:50:02 +0000 2 개 획득 옵션 (10) 개 2020-03-28 23:50:02 +0000 1 개 획득 옵션 (10) 항목 2020-03-28 23:50:02 +0000

참고 : Btw, \(Date())각 인쇄 끝에 추가 했습니다.