82 lines
1.7 KiB
Swift
82 lines
1.7 KiB
Swift
//
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// BatchUpdates.swift
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// DataModel
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//
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// Created by Brent Simmons on 9/12/16.
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// Copyright © 2016 Ranchero Software, LLC. All rights reserved.
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//
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import Foundation
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// Main thread only.
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public typealias BatchUpdateBlock = () -> Void
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public extension Notification.Name {
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/// A notification posted when a batch update completes.
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static let BatchUpdateDidPerform = Notification.Name(rawValue: "BatchUpdateDidPerform")
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}
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/// A class for batch updating.
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@MainActor public final class BatchUpdate {
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/// The shared batch update object.
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@MainActor public static let shared = BatchUpdate()
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private var count = 0
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/// Is updating in progress?
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public var isPerforming: Bool {
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precondition(Thread.isMainThread)
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return count > 0
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}
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/// Perform a batch update.
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public func perform(_ batchUpdateBlock: BatchUpdateBlock) {
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precondition(Thread.isMainThread)
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incrementCount()
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batchUpdateBlock()
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decrementCount()
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}
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/// Start batch updates.
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public func start() {
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precondition(Thread.isMainThread)
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incrementCount()
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}
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/// End batch updates.
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public func end() {
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precondition(Thread.isMainThread)
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decrementCount()
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}
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}
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private extension BatchUpdate {
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func incrementCount() {
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count = count + 1
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}
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func decrementCount() {
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count = count - 1
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if count < 1 {
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assert(count > -1, "Expected batch updates count to be 0 or greater.")
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count = 0
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postBatchUpdateDidPerform()
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}
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}
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func postBatchUpdateDidPerform() {
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if !Thread.isMainThread {
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DispatchQueue.main.sync {
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NotificationCenter.default.post(name: .BatchUpdateDidPerform, object: nil, userInfo: nil)
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}
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} else {
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NotificationCenter.default.post(name: .BatchUpdateDidPerform, object: nil, userInfo: nil)
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}
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}
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}
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