forked from shadowfacts/Tusker
Add DiffableTimelineLikeTableViewController
This commit is contained in:
parent
ebb0770198
commit
49572c1fec
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@ -155,6 +155,7 @@
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D6531DEE246B81C9000F9538 /* GifvAttachmentView.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6531DED246B81C9000F9538 /* GifvAttachmentView.swift */; };
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D6531DF0246B867E000F9538 /* GifvAttachmentViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6531DEF246B867E000F9538 /* GifvAttachmentViewController.swift */; };
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D6538945214D6D7500E3CEFC /* TableViewSwipeActionProvider.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6538944214D6D7500E3CEFC /* TableViewSwipeActionProvider.swift */; };
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D653F411267D1E32004E32B1 /* DiffableTimelineLikeTableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D653F410267D1E32004E32B1 /* DiffableTimelineLikeTableViewController.swift */; };
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D65C6BF525478A9C00A6E89C /* BackgroundableViewController.swift in Sources */ = {isa = PBXBuildFile; fileRef = D65C6BF425478A9C00A6E89C /* BackgroundableViewController.swift */; };
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D65F613423AEAB6600F3CFD3 /* OnboardingTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = D65F613323AEAB6600F3CFD3 /* OnboardingTests.swift */; };
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D6620ACE2511A0ED00312CA0 /* StatusStateResolver.swift in Sources */ = {isa = PBXBuildFile; fileRef = D6620ACD2511A0ED00312CA0 /* StatusStateResolver.swift */; };
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@ -553,6 +554,7 @@
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D6531DED246B81C9000F9538 /* GifvAttachmentView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GifvAttachmentView.swift; sourceTree = "<group>"; };
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D6531DEF246B867E000F9538 /* GifvAttachmentViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = GifvAttachmentViewController.swift; sourceTree = "<group>"; };
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D6538944214D6D7500E3CEFC /* TableViewSwipeActionProvider.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TableViewSwipeActionProvider.swift; sourceTree = "<group>"; };
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D653F410267D1E32004E32B1 /* DiffableTimelineLikeTableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DiffableTimelineLikeTableViewController.swift; sourceTree = "<group>"; };
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D65C6BF425478A9C00A6E89C /* BackgroundableViewController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = BackgroundableViewController.swift; sourceTree = "<group>"; };
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D65F612D23AE990C00F3CFD3 /* Embassy.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = Embassy.framework; sourceTree = BUILT_PRODUCTS_DIR; };
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D65F613023AE99E000F3CFD3 /* Ambassador.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; path = Ambassador.framework; sourceTree = BUILT_PRODUCTS_DIR; };
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@ -1485,6 +1487,7 @@
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D65C6BF425478A9C00A6E89C /* BackgroundableViewController.swift */,
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D6B81F3B2560365300F6E31D /* RefreshableViewController.swift */,
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D65234C8256189D0001AF9CF /* TimelineLikeTableViewController.swift */,
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D653F410267D1E32004E32B1 /* DiffableTimelineLikeTableViewController.swift */,
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D625E4812588262A0074BB2B /* DraggableTableViewCell.swift */,
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D6A6C10425B6138A00298D0F /* StatusTablePrefetching.swift */,
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);
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@ -2151,6 +2154,7 @@
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D626493823C0FD0000612E6E /* AllPhotosTableViewCell.swift in Sources */,
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D627943B23A55BA600D38C68 /* NavigableTableViewCell.swift in Sources */,
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D6333B792139AEFD00CE884A /* Date+TimeAgo.swift in Sources */,
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D653F411267D1E32004E32B1 /* DiffableTimelineLikeTableViewController.swift in Sources */,
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D6C82B5625C5F3F20017F1E6 /* ExpandThreadTableViewCell.swift in Sources */,
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D686BBE324FBF8110068E6AA /* WrappedProgressView.swift in Sources */,
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D620483423D3801D008A63EF /* LinkTextView.swift in Sources */,
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@ -0,0 +1,268 @@
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//
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// DiffableTimelineLikeTableViewController.swift
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// Tusker
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//
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// Created by Shadowfacts on 6/18/21.
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// Copyright © 2021 Shadowfacts. All rights reserved.
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//
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import UIKit
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import Pachyderm
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class DiffableTimelineLikeTableViewController<Section: Hashable & CaseIterable, Item: Hashable>: EnhancedTableViewController, RefreshableViewController {
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typealias Snapshot = NSDiffableDataSourceSnapshot<Section, Item>
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typealias LoadResult = Result<Snapshot, LoadError>
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private let pageSize = 20
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private(set) var state = State.unloaded
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private var lastLastVisibleRow: IndexPath?
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private(set) var dataSource: UITableViewDiffableDataSource<Section, Item>!
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init() {
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super.init(style: .plain)
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addKeyCommand(MenuController.refreshCommand(discoverabilityTitle: Self.refreshCommandTitle()))
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}
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required init?(coder: NSCoder) {
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fatalError("init(coder:) has not been implemented")
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}
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override func viewDidLoad() {
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super.viewDidLoad()
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dataSource = UITableViewDiffableDataSource(tableView: tableView, cellProvider: self.cellProvider)
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tableView.rowHeight = UITableView.automaticDimension
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tableView.estimatedRowHeight = 140
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#if !targetEnvironment(macCatalyst)
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self.refreshControl = UIRefreshControl()
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self.refreshControl!.addTarget(self, action: #selector(refresh), for: .valueChanged)
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#endif
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if let prefetchSource = self as? UITableViewDataSourcePrefetching {
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tableView.prefetchDataSource = prefetchSource
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}
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}
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override func viewWillAppear(_ animated: Bool) {
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super.viewWillAppear(animated)
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loadInitial()
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}
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override func viewDidDisappear(_ animated: Bool) {
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super.viewDidDisappear(animated)
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pruneOffscreenRows()
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}
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class func refreshCommandTitle() -> String {
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return "Refresh"
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}
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private func pruneOffscreenRows() {
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guard let lastVisibleRow = lastLastVisibleRow else {
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return
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}
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var snapshot = dataSource.snapshot()
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let lastVisibleRowSection = snapshot.sectionIdentifiers[lastVisibleRow.section]
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let contentSections = snapshot.sectionIdentifiers.filter { timelineContentSections().contains($0) }
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guard let lastVisibleContentSectionIndex = contentSections.lastIndex(of: lastVisibleRowSection) else {
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return
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}
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if lastVisibleContentSectionIndex < contentSections.count - 1 {
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// there are more content sections below the current last visible one
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let sectionsToRemove = contentSections[lastVisibleContentSectionIndex...]
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snapshot.deleteSections(Array(sectionsToRemove))
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willRemoveItems(sectionsToRemove.flatMap(snapshot.itemIdentifiers(inSection:)))
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} else if lastVisibleContentSectionIndex == contentSections.count - 1 {
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let items = snapshot.itemIdentifiers(inSection: lastVisibleRowSection)
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if lastVisibleRow.row < items.count - pageSize {
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let itemsToRemove = Array(items.suffix(pageSize))
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snapshot.deleteItems(itemsToRemove)
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willRemoveItems(itemsToRemove)
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} else {
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return
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}
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} else {
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return
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}
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dataSource.apply(snapshot, animatingDifferences: false)
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}
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private func loadInitial() {
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guard state == .unloaded else { return }
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// set loaded immediately so we don't trigger another request while the current one is running
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state = .loadingInitial
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loadInitialItems() { result in
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guard case let .success(snapshot) = result else {
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self.state = .unloaded
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return
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}
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DispatchQueue.main.async {
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self.dataSource.apply(snapshot, animatingDifferences: false)
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self.state = .loaded
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}
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}
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}
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func reloadInitial() {
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state = .unloaded
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loadInitial()
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}
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func loadOlder() {
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guard state != .loadingOlder else { return }
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state = .loadingOlder
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loadOlderItems(currentSnapshot: dataSource.snapshot()) { result in
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guard case let .success(snapshot) = result else {
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self.state = .loaded
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return
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}
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DispatchQueue.main.async {
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self.dataSource.apply(snapshot, animatingDifferences: false)
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self.state = .loaded
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}
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}
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}
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func cellHeightChanged() {
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// causes the table view to recalculate the cell heights
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tableView.beginUpdates()
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tableView.endUpdates()
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}
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// MARK: - UITableViewDelegate
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override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
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// this assumes that indexPathsForVisibleRows is always in order
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lastLastVisibleRow = tableView.indexPathsForVisibleRows?.last
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if indexPath.section == tableView.numberOfSections - 1,
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indexPath.row == tableView.numberOfRows(inSection: indexPath.section) - 1 {
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loadOlder()
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}
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}
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override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
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return true
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}
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override func tableView(_ tableView: UITableView, leadingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
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return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.leadingSwipeActionsConfiguration()
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}
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override func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
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return (tableView.cellForRow(at: indexPath) as? TableViewSwipeActionProvider)?.trailingSwipeActionsConfiguration()
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}
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// MARK: - RefreshableViewController
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func refresh() {
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guard state != .loadingNewer else { return }
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state = .loadingNewer
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let snapshot = dataSource.snapshot()
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var item: Item? = nil
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for section in timelineContentSections() {
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if let first = snapshot.itemIdentifiers(inSection: section).first {
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item = first
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break
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}
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}
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loadNewerItems(currentSnapshot: snapshot) { result in
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guard case let .success(snapshot) = result else {
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DispatchQueue.main.async {
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self.refreshControl?.endRefreshing()
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self.state = .loaded
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}
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return
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}
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DispatchQueue.main.async {
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self.refreshControl?.endRefreshing()
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self.dataSource.apply(snapshot, animatingDifferences: false)
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self.state = .loaded
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if let item = item,
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let indexPath = self.dataSource.indexPath(for: item) {
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// maintain the current position in the list (don't scroll to top)
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self.tableView.scrollToRow(at: indexPath, at: .top, animated: false)
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}
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}
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}
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}
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// MARK: - Subclass Methods
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func cellProvider(_ tableView: UITableView, _ indexPath: IndexPath, _ item: Item) -> UITableViewCell? {
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fatalError("cellProvider(_:_:_:) must be implemented by subclasses")
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}
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func loadInitialItems(completion: @escaping (LoadResult) -> Void) {
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fatalError("loadInitialItems(completion:) must be implemented by subclasses")
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}
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func loadOlderItems(currentSnapshot: Snapshot, completion: @escaping (LoadResult) -> Void) {
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fatalError("loadOlderItesm(completion:) must be implemented by subclasses")
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}
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func loadNewerItems(currentSnapshot: Snapshot, completion: @escaping (LoadResult) -> Void) {
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fatalError("loadNewerItems(completion:) must be implemented by subclasses")
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}
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func timelineContentSections() -> Section.AllCases {
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return Section.allCases
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}
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func willRemoveItems(_ items: [Item]) {
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}
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}
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extension DiffableTimelineLikeTableViewController {
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enum State: Equatable {
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case unloaded
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case loadingInitial
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case loaded
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case loadingNewer
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case loadingOlder
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}
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}
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extension DiffableTimelineLikeTableViewController {
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enum LoadError: LocalizedError {
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case noClient
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case noOlder
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case noNewer
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case client(Client.Error)
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}
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}
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extension DiffableTimelineLikeTableViewController: BackgroundableViewController {
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func sceneDidEnterBackground() {
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pruneOffscreenRows()
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}
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}
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@ -9,8 +9,8 @@
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import UIKit
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/// A table view controller that manages common functionality between timeline-like UIs.
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// For example, this class handles loading new items when the user scrolls to the end,
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// refreshing, and pruning offscreen rows automatically.
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/// For example, this class handles loading new items when the user scrolls to the end,
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/// refreshing, and pruning offscreen rows automatically.
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class TimelineLikeTableViewController<Item>: EnhancedTableViewController, RefreshableViewController {
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private(set) var loaded = false
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