135 lines
3.0 KiB
Swift
135 lines
3.0 KiB
Swift
//
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// TreeController.swift
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// NetNewsWire
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//
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// Created by Brent Simmons on 5/29/16.
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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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public protocol TreeControllerDelegate: AnyObject {
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@MainActor func treeController(treeController: TreeController, childNodesFor: Node) -> [Node]?
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}
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public typealias NodeVisitBlock = (_ : Node) -> Void
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@MainActor public final class TreeController {
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private weak var delegate: TreeControllerDelegate?
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public let rootNode: Node
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public init(delegate: TreeControllerDelegate, rootNode: Node) {
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self.delegate = delegate
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self.rootNode = rootNode
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rebuild()
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}
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public convenience init(delegate: TreeControllerDelegate) {
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self.init(delegate: delegate, rootNode: Node.genericRootNode())
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}
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@discardableResult
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public func rebuild() -> Bool {
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// Rebuild and re-sort. Return true if any changes in the entire tree.
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return rebuildChildNodes(node: rootNode)
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}
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public func visitNodes(_ visitBlock: NodeVisitBlock) {
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visitNode(rootNode, visitBlock)
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}
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public func nodeInArrayRepresentingObject(nodes: [Node], representedObject: AnyObject, recurse: Bool = false) -> Node? {
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for oneNode in nodes {
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if oneNode.representedObject === representedObject {
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return oneNode
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}
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if recurse, oneNode.canHaveChildNodes {
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if let foundNode = nodeInArrayRepresentingObject(nodes: oneNode.childNodes, representedObject: representedObject, recurse: recurse) {
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return foundNode
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}
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}
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}
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return nil
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}
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public func nodeInTreeRepresentingObject(_ representedObject: AnyObject) -> Node? {
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return nodeInArrayRepresentingObject(nodes: [rootNode], representedObject: representedObject, recurse: true)
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}
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public func normalizedSelectedNodes(_ nodes: [Node]) -> [Node] {
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// An array of nodes might include a leaf node and its parent. Remove the leaf node.
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var normalizedNodes = [Node]()
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for node in nodes {
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if !node.hasAncestor(in: nodes) {
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normalizedNodes += [node]
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}
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}
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return normalizedNodes
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}
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}
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private extension TreeController {
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func visitNode(_ node: Node, _ visitBlock: NodeVisitBlock) {
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visitBlock(node)
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for oneChildNode in node.childNodes {
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visitNode(oneChildNode, visitBlock)
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}
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}
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func nodeArraysAreEqual(_ nodeArray1: [Node]?, _ nodeArray2: [Node]?) -> Bool {
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if nodeArray1 == nil && nodeArray2 == nil {
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return true
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}
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if nodeArray1 != nil && nodeArray2 == nil {
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return false
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}
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if nodeArray1 == nil && nodeArray2 != nil {
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return false
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}
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return nodeArray1! == nodeArray2!
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}
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func rebuildChildNodes(node: Node) -> Bool {
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if !node.canHaveChildNodes {
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return false
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}
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let childNodes = delegate?.treeController(treeController: self, childNodesFor: node) ?? [Node]()
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var childNodesDidChange = !nodeArraysAreEqual(childNodes, node.childNodes)
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if childNodesDidChange {
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node.childNodes = childNodes
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}
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for oneChildNode in childNodes {
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if rebuildChildNodes(node: oneChildNode) {
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childNodesDidChange = true
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}
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}
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return childNodesDidChange
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}
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}
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