55 lines
1.6 KiB
Swift
55 lines
1.6 KiB
Swift
//
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// Copyright (c) 2019 Open Whisper Systems. All rights reserved.
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//
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import Foundation
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// ObjC compatible searcher
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@objc class AnySearcher: NSObject {
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private let searcher: Searcher<AnyObject>
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public init(indexer: @escaping (AnyObject) -> String ) {
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searcher = Searcher(indexer: indexer)
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super.init()
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}
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@objc(item:doesMatchQuery:)
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public func matches(item: AnyObject, query: String) -> Bool {
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return searcher.matches(item: item, query: query)
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}
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}
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// A generic searching class, configurable with an indexing block
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public class Searcher<T> {
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private let indexer: (T) -> String
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public init(indexer: @escaping (T) -> String) {
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self.indexer = indexer
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}
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public func matches(item: T, query: String) -> Bool {
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let itemString = normalize(string: indexer(item))
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return stem(string: query).map { queryStem in
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return itemString.contains(queryStem)
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}.reduce(true) { $0 && $1 }
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}
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private func stem(string: String) -> [String] {
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var normalized = normalize(string: string)
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// Remove any phone number formatting from the search terms
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let nonformattingScalars = normalized.unicodeScalars.lazy.filter {
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!CharacterSet.punctuationCharacters.contains($0)
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}
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normalized = String(String.UnicodeScalarView(nonformattingScalars))
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return normalized.components(separatedBy: .whitespacesAndNewlines)
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}
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private func normalize(string: String) -> String {
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return string.lowercased().trimmingCharacters(in: .whitespacesAndNewlines)
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}
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}
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