Add basic ExtensionPoint support.

Shared/Extensions/CacheCleaner.swift

@@ -0,0 +1,51 @@
+//
+//  CacheCleaner.swift
+//  NetNewsWire
+//
+//  Created by Maurice Parker on 11/8/19.
+//  Copyright © 2019 Ranchero Software. All rights reserved.
+//
+
+import Foundation
+import os.log
+
+struct CacheCleaner {
+
+	static let log = OSLog(subsystem: Bundle.main.bundleIdentifier!, category: "CacheCleaner")
+
+	static func purgeIfNecessary() {
+
+		guard let flushDate = AppDefaults.lastImageCacheFlushDate else {
+			AppDefaults.lastImageCacheFlushDate = Date()
+			return
+		}
+		
+		// If the image disk cache hasn't been flushed for 3 days and the network is available, delete it
+		if flushDate.addingTimeInterval(3600 * 24 * 3) < Date() {
+			if let reachability = try? Reachability(hostname: "apple.com") {
+				if reachability.connection != .unavailable {
+
+					let tempDir = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first!
+					let faviconsFolderURL = tempDir.appendingPathComponent("Favicons")
+					let imagesFolderURL = tempDir.appendingPathComponent("Images")
+					let homePageToIconURL = tempDir.appendingPathComponent("HomePageToIconURLCache.plist")
+					let homePagesWithNoIconURL = tempDir.appendingPathComponent("HomePagesWithNoIconURLCache.plist")
+
+					for tempItem in [faviconsFolderURL, imagesFolderURL, homePageToIconURL, homePagesWithNoIconURL] {
+						do {
+							os_log(.info, log: self.log, "Removing cache file: %@", tempItem.absoluteString)
+							try FileManager.default.removeItem(at: tempItem)
+						} catch {
+							os_log(.error, log: self.log, "Could not delete cache file: %@", error.localizedDescription)
+						}
+					}
+					
+					AppDefaults.lastImageCacheFlushDate = Date()
+					
+				}
+			}
+		}
+		
+	}
+	
+}