62 lines
1.5 KiB
Swift
62 lines
1.5 KiB
Swift
//
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// Collector.swift
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// SwiftSoup
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//
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// Created by Nabil Chatbi on 22/10/16.
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// Copyright © 2016 Nabil Chatbi.. All rights reserved.
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//
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import Foundation
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/**
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* Collects a list of elements that match the supplied criteria.
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*
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* @author Jonathan Hedley
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*/
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open class Collector {
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private init() {
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}
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/**
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Build a list of elements, by visiting root and every descendant of root, and testing it against the evaluator.
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@param eval Evaluator to test elements against
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@param root root of tree to descend
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@return list of matches; empty if none
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*/
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open static func collect (_ eval: Evaluator, _ root: Element)throws->Elements {
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let elements : Elements = Elements()
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try NodeTraversor(Accumulator(root, elements, eval)).traverse(root)
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return elements;
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}
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}
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private final class Accumulator : NodeVisitor {
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private let root: Element;
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private let elements: Elements;
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private let eval: Evaluator;
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init(_ root: Element, _ elements: Elements, _ eval: Evaluator) {
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self.root = root;
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self.elements = elements;
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self.eval = eval;
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}
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open func head(_ node: Node, _ depth: Int) {
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if let el = node as? Element
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{
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do{
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if (try eval.matches(root, el)){
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elements.add(el);
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}
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}catch{}
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}
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}
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open func tail(_ node: Node, _ depth: Int) {
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// void
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}
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}
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