Add basic ExtensionPoint support.

Shared/Extensions/ArticleStringFormatter.swift

@@ -0,0 +1,109 @@
+//
+//  ArticleStringFormatter.swift
+//  NetNewsWire
+//
+//  Created by Brent Simmons on 8/31/15.
+//  Copyright © 2015 Ranchero Software, LLC. All rights reserved.
+//
+
+import Foundation
+import Articles
+import RSParser
+
+struct ArticleStringFormatter {
+
+	private static var feedNameCache = [String: String]()
+	private static var titleCache = [String: String]()
+	private static var summaryCache = [String: String]()
+
+	private static let dateFormatter: DateFormatter = {
+		let formatter = DateFormatter()
+		formatter.dateStyle = .medium
+		formatter.timeStyle = .none
+		return formatter
+	}()
+
+	private static let timeFormatter: DateFormatter = {
+		let formatter = DateFormatter()
+		formatter.dateStyle = .none
+		formatter.timeStyle = .short
+		return formatter
+	}()
+
+	static func emptyCaches() {
+		feedNameCache = [String: String]()
+		titleCache = [String: String]()
+		summaryCache = [String: String]()
+	}
+
+	static func truncatedFeedName(_ feedName: String) -> String {
+		if let cachedFeedName = feedNameCache[feedName] {
+			return cachedFeedName
+		}
+
+		let maxFeedNameLength = 100
+		if feedName.count < maxFeedNameLength {
+			feedNameCache[feedName] = feedName
+			return feedName
+		}
+
+		let s = (feedName as NSString).substring(to: maxFeedNameLength)
+		feedNameCache[feedName] = s
+		return s
+	}
+
+	static func truncatedTitle(_ article: Article) -> String {
+		guard let title = article.title else {
+			return ""
+		}
+
+		if let cachedTitle = titleCache[title] {
+			return cachedTitle
+		}
+
+		var s = title.replacingOccurrences(of: "\n", with: "")
+		s = s.replacingOccurrences(of: "\r", with: "")
+		s = s.replacingOccurrences(of: "\t", with: "")
+		s = s.rsparser_stringByDecodingHTMLEntities()
+		s = s.trimmingWhitespace
+		s = s.collapsingWhitespace
+
+		let maxLength = 1000
+		if s.count < maxLength {
+			titleCache[title] = s
+			return s
+		}
+
+		s = (s as NSString).substring(to: maxLength)
+		titleCache[title] = s
+		return s
+	}
+
+	static func truncatedSummary(_ article: Article) -> String {
+		guard let body = article.body else {
+			return ""
+		}
+
+		let key = article.articleID + article.accountID
+		if let cachedBody = summaryCache[key] {
+			return cachedBody
+		}
+		var s = body.rsparser_stringByDecodingHTMLEntities()
+		s = s.strippingHTML(maxCharacters: 250)
+		s = s.trimmingWhitespace
+		s = s.collapsingWhitespace
+		if s == "Comments" { // Hacker News.
+			s = ""
+		}
+		summaryCache[key] = s
+		return s
+	}
+
+	static func dateString(_ date: Date) -> String {
+		if Calendar.dateIsToday(date) {
+			return timeFormatter.string(from: date)
+		}
+		return dateFormatter.string(from: date)
+	}
+}
+