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Renamed LiveList to ListPublisher and LiveObject to ObjectPublisher. WIP: docs
This commit is contained in:
John Estropia
@@ -1,543 +0,0 @@
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//
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// LiveList.swift
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// CoreStore
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//
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// Copyright © 2018 John Rommel Estropia
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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 all
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// 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 THE
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// SOFTWARE.
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//
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import CoreData
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#if canImport(Combine)
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import Combine
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#endif
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#if canImport(SwiftUI)
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import SwiftUI
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#endif
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// MARK: - LiveList
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/**
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`LiveList` tracks a diffable list of `DynamicObject` instances. Unlike `ListMonitor`s, `LiveList` are more lightweight and access objects lazily. `LiveList`s are also designed to work well with `DiffableDataSource.TableView`s and `DiffableDataSource.CollectionView`s. Objects that need to be notified of `LiveList` changes may register themselves to its `addObserver(_:_:)` method:
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```
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let liveList = Shared.defaultStack.liveList(
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From<Person>()
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.where(\.title == "Engineer")
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.orderBy(.ascending(\.lastName))
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)
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liveList.addObserver(self) { (liveList) in
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// Handle changes
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}
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```
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The `LiveList` instance needs to be held on (retained) for as long as the list needs to be observed.
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Observers registered via `addObserver(_:_:)` are not retained. `LiveList` only keeps a `weak` reference to all observers, thus keeping itself free from retain-cycles.
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`LiveList`s may optionally be created with sections:
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```
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let liveList = Shared.defaultStack.liveList(
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From<Person>()
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.sectionBy(\.age") { "Age \($0)" }
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.where(\.title == "Engineer")
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.orderBy(.ascending(\.lastName))
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)
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liveList.addObserver(self) { (liveList) in
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// Handle changes
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}
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```
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*/
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@available(macOS 10.12, *)
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public final class LiveList<O: DynamicObject>: Hashable {
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// MARK: Public
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public typealias SectionID = SnapshotType.SectionID
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public typealias ItemID = SnapshotType.ItemID
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public subscript(section sectionID: SectionID) -> [LiveObject<O>] {
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let context = self.context
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return self.snapshot
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.itemIdentifiers(inSection: sectionID)
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.map({ context.liveObject(objectID: $0) })
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}
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public subscript(itemID itemID: ItemID) -> LiveObject<O>? {
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guard let validID = self.snapshot.itemIdentifiers.first(where: { $0 == itemID }) else {
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return nil
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}
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return self.context.liveObject(objectID: validID)
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}
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public subscript(indexPath indexPath: IndexPath) -> LiveObject<O>? {
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let snapshot = self.snapshot
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let sectionIdentifiers = snapshot.sectionIdentifiers
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guard sectionIdentifiers.indices.contains(indexPath.section) else {
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return nil
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}
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let sectionID = sectionIdentifiers[indexPath.section]
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let itemIdentifiers = snapshot.itemIdentifiers(inSection: sectionID)
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guard itemIdentifiers.indices.contains(indexPath.item) else {
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return nil
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}
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let itemID = itemIdentifiers[indexPath.item]
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return self.context.liveObject(objectID: itemID)
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}
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public subscript<S: Sequence>(section sectionID: SectionID, itemIndices itemIndices: S) -> [LiveObject<O>] where S.Element == Int {
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let context = self.context
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let itemIDs = self.snapshot.itemIdentifiers(inSection: sectionID)
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return itemIndices.map { position in
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let itemID = itemIDs[position]
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return context.liveObject(objectID: itemID)
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}
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}
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public fileprivate(set) var snapshot: SnapshotType = .init() {
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willSet {
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self.willChange()
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}
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didSet {
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self.notifyObservers()
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self.didChange()
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}
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}
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public var numberOfItems: Int {
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return self.snapshot.numberOfItems
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}
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public var numberOfSections: Int {
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return self.snapshot.numberOfSections
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}
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public var sectionIdentifiers: [SectionID] {
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return self.snapshot.sectionIdentifiers
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}
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public var items: [LiveObject<O>] {
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let context = self.context
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return self.snapshot.itemIdentifiers
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.map({ context.liveObject(objectID: $0) })
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}
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public func numberOfItems(inSection identifier: SectionID) -> Int {
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return self.snapshot.numberOfItems(inSection: identifier)
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}
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public func items(inSection identifier: SectionID) -> [LiveObject<O>] {
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let context = self.context
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return self.snapshot
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.itemIdentifiers(inSection: identifier)
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.map({ context.liveObject(objectID: $0) })
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}
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public func items(inSection identifier: SectionID, atIndices indices: IndexSet) -> [LiveObject<O>] {
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let context = self.context
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let itemIDs = self.snapshot.itemIdentifiers(inSection: identifier)
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return indices.map { position in
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let itemID = itemIDs[position]
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return context.liveObject(objectID: itemID)
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}
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}
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public func section(containingItem item: LiveObject<O>) -> SectionID? {
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return self.snapshot.sectionIdentifier(containingItem: item.objectID())
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}
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public func indexOfItem(_ item: LiveObject<O>) -> Int? {
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return self.snapshot.indexOfItem(item.objectID())
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}
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public func indexOfSection(_ identifier: SectionID) -> Int? {
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return self.snapshot.indexOfSection(identifier)
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}
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public func addObserver<T: AnyObject>(_ observer: T, _ callback: @escaping (LiveList<O>) -> Void) {
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self.observers.setObject(
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Internals.Closure(callback),
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forKey: observer
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)
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}
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public func removeObserver<T: AnyObject>(_ observer: T) {
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self.observers.removeObject(forKey: observer)
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}
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// MARK: Public (Refetching)
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/**
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Asks the `ListMonitor` to refetch its objects using the specified series of `FetchClause`s. Note that this method does not execute the fetch immediately; the actual fetching will happen after the `NSFetchedResultsController`'s last `controllerDidChangeContent(_:)` notification completes.
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`refetch(...)` broadcasts `listMonitorWillRefetch(...)` to its observers immediately, and then `listMonitorDidRefetch(...)` after the new fetch request completes.
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- parameter fetchClauses: a series of `FetchClause` instances for fetching the object list. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
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- Important: Starting CoreStore 4.0, all `FetchClause`s required by the `ListMonitor` should be provided in the arguments list of `refetch(...)`.
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*/
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public func refetch(_ fetchClauses: FetchClause...) {
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self.refetch(fetchClauses)
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}
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/**
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Asks the `ListMonitor` to refetch its objects using the specified series of `FetchClause`s. Note that this method does not execute the fetch immediately; the actual fetching will happen after the `NSFetchedResultsController`'s last `controllerDidChangeContent(_:)` notification completes.
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`refetch(...)` broadcasts `listMonitorWillRefetch(...)` to its observers immediately, and then `listMonitorDidRefetch(...)` after the new fetch request completes.
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- parameter fetchClauses: a series of `FetchClause` instances for fetching the object list. Accepts `Where`, `OrderBy`, and `Tweak` clauses.
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- Important: Starting CoreStore 4.0, all `FetchClause`s required by the `ListMonitor` should be provided in the arguments list of `refetch(...)`.
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*/
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public func refetch(_ fetchClauses: [FetchClause]) {
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self.refetch { (fetchRequest) in
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fetchClauses.forEach { $0.applyToFetchRequest(fetchRequest) }
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}
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}
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// MARK: Public (3rd Party Utilities)
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/**
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Allow external libraries to store custom data in the `ListMonitor`. App code should rarely have a need for this.
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```
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enum Static {
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static var myDataKey: Void?
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}
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monitor.userInfo[&Static.myDataKey] = myObject
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```
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- Important: Do not use this method to store thread-sensitive data.
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*/
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public let userInfo = UserInfo()
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// MARK: Equatable
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public static func == (_ lhs: LiveList, _ rhs: LiveList) -> Bool {
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return lhs === rhs
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}
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// MARK: Hashable
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public func hash(into hasher: inout Hasher) {
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hasher.combine(ObjectIdentifier(self))
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}
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// MARK: LiveResult
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public typealias ObjectType = O
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public typealias SnapshotType = ListSnapshot<O>
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// MARK: Internal
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internal convenience init(dataStack: DataStack, from: From<ObjectType>, sectionBy: SectionBy<ObjectType>?, applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void) {
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self.init(
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context: dataStack.mainContext,
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from: from,
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sectionBy: sectionBy,
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applyFetchClauses: applyFetchClauses,
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createAsynchronously: nil
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)
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}
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internal convenience init(dataStack: DataStack, from: From<ObjectType>, sectionBy: SectionBy<ObjectType>?, applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void, createAsynchronously: @escaping (LiveList<ObjectType>) -> Void) {
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self.init(
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context: dataStack.mainContext,
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from: from,
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sectionBy: sectionBy,
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applyFetchClauses: applyFetchClauses,
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createAsynchronously: createAsynchronously
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)
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}
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internal convenience init(unsafeTransaction: UnsafeDataTransaction, from: From<ObjectType>, sectionBy: SectionBy<ObjectType>?, applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void) {
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self.init(
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context: unsafeTransaction.context,
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from: from,
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sectionBy: sectionBy,
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applyFetchClauses: applyFetchClauses,
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createAsynchronously: nil
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)
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}
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internal convenience init(unsafeTransaction: UnsafeDataTransaction, from: From<ObjectType>, sectionBy: SectionBy<ObjectType>?, applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void, createAsynchronously: @escaping (LiveList<ObjectType>) -> Void) {
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self.init(
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context: unsafeTransaction.context,
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from: from,
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sectionBy: sectionBy,
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applyFetchClauses: applyFetchClauses,
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createAsynchronously: createAsynchronously
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)
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}
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internal func refetch(_ applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void) {
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self.applyFetchClauses = applyFetchClauses
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DispatchQueue.main.async { [weak self] () -> Void in
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guard let `self` = self else {
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return
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}
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let (newFetchedResultsController, newFetchedResultsControllerDelegate) = Self.recreateFetchedResultsController(
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context: self.fetchedResultsController.managedObjectContext,
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from: self.from,
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sectionBy: self.sectionBy,
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applyFetchClauses: self.applyFetchClauses
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)
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newFetchedResultsControllerDelegate.handler = self
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do {
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try newFetchedResultsController.performFetchFromSpecifiedStores()
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}
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catch {
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// DataStack may have been deallocated
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return
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}
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(self.fetchedResultsController, self.fetchedResultsControllerDelegate) = (newFetchedResultsController, newFetchedResultsControllerDelegate)
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}
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}
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deinit {
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self.fetchedResultsControllerDelegate.fetchedResultsController = nil
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self.observers.removeAllObjects()
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}
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// MARK: FilePrivate
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fileprivate let rawObjectWillChange: Any?
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// MARK: Private
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private var fetchedResultsController: Internals.CoreStoreFetchedResultsController
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private var fetchedResultsControllerDelegate: Internals.FetchedDiffableDataSourceSnapshotDelegate
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private let sectionIndexTransformer: (_ sectionName: KeyPathString?) -> String?
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private var applyFetchClauses: (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void
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private var observerForWillChangePersistentStore: Internals.NotificationObserver!
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private var observerForDidChangePersistentStore: Internals.NotificationObserver!
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private let from: From<ObjectType>
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private let sectionBy: SectionBy<ObjectType>?
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private lazy var observers: NSMapTable<AnyObject, Internals.Closure<LiveList<O>, Void>> = .weakToStrongObjects()
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private lazy var context: NSManagedObjectContext = self.fetchedResultsController.managedObjectContext
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private static func recreateFetchedResultsController(context: NSManagedObjectContext, from: From<ObjectType>, sectionBy: SectionBy<ObjectType>?, applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void) -> (controller: Internals.CoreStoreFetchedResultsController, delegate: Internals.FetchedDiffableDataSourceSnapshotDelegate) {
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let fetchRequest = Internals.CoreStoreFetchRequest<NSManagedObject>()
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fetchRequest.fetchLimit = 0
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fetchRequest.resultType = .managedObjectResultType
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fetchRequest.includesPendingChanges = false
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fetchRequest.shouldRefreshRefetchedObjects = true
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let fetchedResultsController = Internals.CoreStoreFetchedResultsController(
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context: context,
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fetchRequest: fetchRequest,
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from: from,
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sectionBy: sectionBy,
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applyFetchClauses: applyFetchClauses
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)
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let fetchedResultsControllerDelegate = Internals.FetchedDiffableDataSourceSnapshotDelegate()
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fetchedResultsControllerDelegate.fetchedResultsController = fetchedResultsController
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return (fetchedResultsController, fetchedResultsControllerDelegate)
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}
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private init(context: NSManagedObjectContext, from: From<ObjectType>, sectionBy: SectionBy<ObjectType>?, applyFetchClauses: @escaping (_ fetchRequest: Internals.CoreStoreFetchRequest<NSManagedObject>) -> Void, createAsynchronously: ((LiveList<ObjectType>) -> Void)?) {
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self.from = from
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self.sectionBy = sectionBy
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(self.fetchedResultsController, self.fetchedResultsControllerDelegate) = Self.recreateFetchedResultsController(
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context: context,
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from: from,
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sectionBy: sectionBy,
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applyFetchClauses: applyFetchClauses
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)
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||||
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if #available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *) {
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||||
|
||||
#if canImport(Combine)
|
||||
self.rawObjectWillChange = ObservableObjectPublisher()
|
||||
|
||||
#else
|
||||
self.rawObjectWillChange = nil
|
||||
|
||||
#endif
|
||||
}
|
||||
else {
|
||||
|
||||
self.rawObjectWillChange = nil
|
||||
}
|
||||
|
||||
if let sectionIndexTransformer = sectionBy?.sectionIndexTransformer {
|
||||
|
||||
self.sectionIndexTransformer = sectionIndexTransformer
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}
|
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else {
|
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|
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self.sectionIndexTransformer = { $0 }
|
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}
|
||||
self.applyFetchClauses = applyFetchClauses
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||||
self.fetchedResultsControllerDelegate.handler = self
|
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|
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try! self.fetchedResultsController.performFetchFromSpecifiedStores()
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}
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||||
|
||||
private func notifyObservers() {
|
||||
|
||||
guard let enumerator = self.observers.objectEnumerator() else {
|
||||
|
||||
return
|
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}
|
||||
for closure in enumerator {
|
||||
|
||||
(closure as! Internals.Closure<LiveList<O>, Void>).invoke(with: self)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
// MARK: - LiveList: FetchedDiffableDataSourceSnapshotHandler
|
||||
|
||||
extension LiveList: FetchedDiffableDataSourceSnapshotHandler {
|
||||
|
||||
// MARK: FetchedDiffableDataSourceSnapshotHandler
|
||||
|
||||
// @available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
|
||||
// internal func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChangeContentWith snapshot: NSDiffableDataSourceSnapshot<String, NSManagedObjectID>) {
|
||||
//
|
||||
// self.snapshot = .init(
|
||||
// diffableSnapshot: snapshot,
|
||||
// context: controller.managedObjectContext
|
||||
// )
|
||||
// }
|
||||
|
||||
internal func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChangeContentWith snapshot: Internals.DiffableDataSourceSnapshot) {
|
||||
|
||||
self.snapshot = .init(
|
||||
diffableSnapshot: snapshot,
|
||||
context: controller.managedObjectContext
|
||||
)
|
||||
}
|
||||
|
||||
internal func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, sectionIndexTitleForSectionName sectionName: String?) -> String? {
|
||||
|
||||
return self.sectionIndexTransformer(sectionName)
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
#if canImport(Combine)
|
||||
import Combine
|
||||
|
||||
@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
|
||||
extension LiveList: ObservableObject {}
|
||||
|
||||
#endif
|
||||
|
||||
// MARK: - LiveList: LiveResult
|
||||
|
||||
extension LiveList: LiveResult {
|
||||
|
||||
// MARK: ObservableObject
|
||||
|
||||
#if canImport(Combine)
|
||||
|
||||
@available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *)
|
||||
public var objectWillChange: ObservableObjectPublisher {
|
||||
|
||||
return self.rawObjectWillChange! as! ObservableObjectPublisher
|
||||
}
|
||||
|
||||
#endif
|
||||
|
||||
public func willChange() {
|
||||
|
||||
guard #available(iOS 13.0, tvOS 13.0, watchOS 6.0, macOS 10.15, *) else {
|
||||
|
||||
return
|
||||
}
|
||||
#if canImport(Combine)
|
||||
|
||||
#if canImport(SwiftUI)
|
||||
withAnimation {
|
||||
|
||||
self.objectWillChange.send()
|
||||
}
|
||||
|
||||
#endif
|
||||
|
||||
self.objectWillChange.send()
|
||||
|
||||
#endif
|
||||
}
|
||||
|
||||
public func didChange() {
|
||||
|
||||
// TODO:
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user