//
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// RequestTaskMap.swift
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//
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// Copyright (c) 2014-2018 Alamofire Software Foundation (http://alamofire.org/)
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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//
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import Foundation
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/// A type that maintains a two way, one to one map of `URLSessionTask`s to `Request`s.
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struct RequestTaskMap {
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private typealias Events = (completed: Bool, metricsGathered: Bool)
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private var tasksToRequests: [URLSessionTask: Request]
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private var requestsToTasks: [Request: URLSessionTask]
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private var taskEvents: [URLSessionTask: Events]
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var requests: [Request] {
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Array(tasksToRequests.values)
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}
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init(tasksToRequests: [URLSessionTask: Request] = [:],
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requestsToTasks: [Request: URLSessionTask] = [:],
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taskEvents: [URLSessionTask: (completed: Bool, metricsGathered: Bool)] = [:]) {
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self.tasksToRequests = tasksToRequests
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self.requestsToTasks = requestsToTasks
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self.taskEvents = taskEvents
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}
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subscript(_ request: Request) -> URLSessionTask? {
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get { requestsToTasks[request] }
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set {
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guard let newValue else {
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guard let task = requestsToTasks[request] else {
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fatalError("RequestTaskMap consistency error: no task corresponding to request found.")
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}
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requestsToTasks.removeValue(forKey: request)
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tasksToRequests.removeValue(forKey: task)
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taskEvents.removeValue(forKey: task)
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return
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}
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requestsToTasks[request] = newValue
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tasksToRequests[newValue] = request
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taskEvents[newValue] = (completed: false, metricsGathered: false)
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}
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}
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subscript(_ task: URLSessionTask) -> Request? {
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get { tasksToRequests[task] }
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set {
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guard let newValue else {
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guard let request = tasksToRequests[task] else {
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fatalError("RequestTaskMap consistency error: no request corresponding to task found.")
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}
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tasksToRequests.removeValue(forKey: task)
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requestsToTasks.removeValue(forKey: request)
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taskEvents.removeValue(forKey: task)
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return
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}
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tasksToRequests[task] = newValue
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requestsToTasks[newValue] = task
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taskEvents[task] = (completed: false, metricsGathered: false)
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}
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}
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var count: Int {
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precondition(tasksToRequests.count == requestsToTasks.count,
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"RequestTaskMap.count invalid, requests.count: \(tasksToRequests.count) != tasks.count: \(requestsToTasks.count)")
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return tasksToRequests.count
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}
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var eventCount: Int {
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precondition(taskEvents.count == count, "RequestTaskMap.eventCount invalid, count: \(count) != taskEvents.count: \(taskEvents.count)")
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return taskEvents.count
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}
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var isEmpty: Bool {
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precondition(tasksToRequests.isEmpty == requestsToTasks.isEmpty,
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"RequestTaskMap.isEmpty invalid, requests.isEmpty: \(tasksToRequests.isEmpty) != tasks.isEmpty: \(requestsToTasks.isEmpty)")
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return tasksToRequests.isEmpty
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}
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var isEventsEmpty: Bool {
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precondition(taskEvents.isEmpty == isEmpty, "RequestTaskMap.isEventsEmpty invalid, isEmpty: \(isEmpty) != taskEvents.isEmpty: \(taskEvents.isEmpty)")
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return taskEvents.isEmpty
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}
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mutating func disassociateIfNecessaryAfterGatheringMetricsForTask(_ task: URLSessionTask) -> Bool {
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guard let events = taskEvents[task] else {
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fatalError("RequestTaskMap consistency error: no events corresponding to task found.")
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}
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switch (events.completed, events.metricsGathered) {
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case (_, true): fatalError("RequestTaskMap consistency error: duplicate metricsGatheredForTask call.")
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case (false, false): taskEvents[task] = (completed: false, metricsGathered: true); return false
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case (true, false): self[task] = nil; return true
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}
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}
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mutating func disassociateIfNecessaryAfterCompletingTask(_ task: URLSessionTask) -> Bool {
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guard let events = taskEvents[task] else {
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fatalError("RequestTaskMap consistency error: no events corresponding to task found.")
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}
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switch (events.completed, events.metricsGathered) {
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case (true, _): fatalError("RequestTaskMap consistency error: duplicate completionReceivedForTask call.")
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// swift-corelibs-foundation doesn't gather metrics, so unconditionally remove the reference and return true.
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#if canImport(FoundationNetworking)
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default: self[task] = nil; return true
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#else
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case (false, false):
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if #available(macOS 10.12, iOS 10, watchOS 7, tvOS 10, *) {
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taskEvents[task] = (completed: true, metricsGathered: false); return false
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} else {
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// watchOS < 7 doesn't gather metrics, so unconditionally remove the reference and return true.
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self[task] = nil; return true
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}
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case (false, true):
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self[task] = nil; return true
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#endif
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}
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}
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}
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