Merge pull request #989 from kiwix/remove-ordered-dependency

Remove OrderedCollections dependency

Tests/OrderedCacheTests.swift

@@ -0,0 +1,63 @@
+// This file is part of Kiwix for iOS & macOS.
+//
+// Kiwix is free software; you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// any later version.
+//
+// Kiwix is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Kiwix; If not, see https://www.gnu.org/licenses/.
+
+import XCTest
+@testable import Kiwix
+
+final class OrderedCacheTests: XCTestCase {
+
+    @MainActor
+    func testEmpty() {
+        let cache = OrderedCache<String, String>()
+        XCTAssertEqual(cache.count, 0)
+        XCTAssertNil(cache.findBy(key: "not to be found"))
+    }
+
+    @MainActor
+    func testOneItem() {
+        let cache = OrderedCache<String, String>()
+        let pastDate = Date.distantPast
+        cache.setValue("test_value", forKey: "keyOne", dated: pastDate)
+        XCTAssertEqual(cache.count, 1)
+        XCTAssertNil(cache.findBy(key: "not to be found"))
+        XCTAssertEqual(cache.findBy(key: "keyOne"), "test_value")
+        cache.removeOlderThan(pastDate)
+        XCTAssertEqual(cache.count, 1)
+        cache.removeOlderThan(Date.now)
+        XCTAssertEqual(cache.count, 0)
+    }
+
+    @MainActor
+    func testRemoveOlderThan() {
+        let cache = OrderedCache<String, String>()
+        let nowDate = Date.now
+        cache.setValue("test_value", forKey: "keyOne", dated: nowDate)
+        cache.setValue("old_value", forKey: "keyOld", dated: Date.distantPast)
+        XCTAssertEqual(cache.count, 2)
+        cache.removeOlderThan(nowDate.advanced(by: -1))
+        XCTAssertEqual(cache.count, 1)
+    }
+
+    @MainActor
+    func testRemoveByKey() {
+        let cache = OrderedCache<String, Int>()
+        cache.setValue(1, forKey: "one")
+        cache.setValue(0, forKey: "zero")
+        cache.removeValue(forKey: "zero")
+        XCTAssertNil(cache.findBy(key: "zero"))
+        XCTAssertEqual(cache.findBy(key: "one"), 1)
+    }
+
+}

ViewModel/BrowserViewModel.swift

@@ -19,8 +19,6 @@ import CoreLocation
 import WebKit
 import Defaults
 import os
-
-import OrderedCollections
 import CoreKiwix
 
 // swiftlint:disable file_length
@@ -28,23 +26,27 @@ import CoreKiwix
 final class BrowserViewModel: NSObject, ObservableObject,
                               WKNavigationDelegate, WKScriptMessageHandler, WKUIDelegate,
                               NSFetchedResultsControllerDelegate {
-    private static var cache = OrderedDictionary<NSManagedObjectID, BrowserViewModel>()
+    @MainActor
+    private static var cache: OrderedCache<NSManagedObjectID, BrowserViewModel>?
 
     @MainActor
     static func getCached(tabID: NSManagedObjectID) -> BrowserViewModel {
-        let viewModel = cache[tabID] ?? BrowserViewModel(tabID: tabID)
-        cache.removeValue(forKey: tabID)
-        cache[tabID] = viewModel
+        if let cachedModel = cache?.findBy(key: tabID) {
+            return cachedModel
+        }
+        if cache == nil {
+            cache = .init()
+        }
+        let viewModel = BrowserViewModel(tabID: tabID)
+        cache?.removeValue(forKey: tabID)
+        cache?.setValue(viewModel, forKey: tabID)
         return viewModel
     }
 
     static func purgeCache() {
-        guard cache.count > 10 else { return }
-        let range = 0 ..< cache.count - 5
-        cache.values[range].forEach { viewModel in
-            viewModel.persistState()
+        Task { @MainActor in
+            cache?.removeOlderThan(Date.now.advanced(by: -360)) // 6 minutes
         }
-        cache.removeSubrange(range)
     }
 
     // MARK: - Properties

ViewModel/OrderedCache.swift

@@ -0,0 +1,56 @@
+// This file is part of Kiwix for iOS & macOS.
+//
+// Kiwix is free software; you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// any later version.
+//
+// Kiwix is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Kiwix; If not, see https://www.gnu.org/licenses/.
+
+import Foundation
+
+@MainActor
+final class OrderedCache<Key: Hashable, Value> {
+
+    private struct ValueDated<V> {
+        let value: V
+        let date: Date
+    }
+
+    private var dict: [Key: ValueDated<Value>] = [:]
+
+    var count: Int {
+        dict.count
+    }
+
+    func findBy(key: Key) -> Value? {
+        if let dateValue = dict[key] {
+            return dateValue.value
+        }
+        return nil
+    }
+
+    func removeAll() {
+        dict = [:]
+    }
+
+    func removeOlderThan(_ pastDate: Date) {
+        dict = dict.filter { (_, value: ValueDated<Value>) in
+            value.date >= pastDate
+        }
+    }
+
+    func setValue(_ value: Value, forKey key: Key, dated: Date = Date.now) {
+        dict[key] = ValueDated(value: value, date: dated)
+    }
+
+    func removeValue(forKey key: Key) {
+        dict.removeValue(forKey: key)
+    }
+}

project.yml

@@ -48,9 +48,6 @@ packages:
   Defaults:
     url: https://github.com/sindresorhus/Defaults
     majorVersion: 6.0.0
-  OrderedCollections:
-    url: https://github.com/apple/swift-collections.git
-    majorVersion: 1.0.4
 
 targetTemplates:
   ApplicationTemplate:
@@ -73,7 +70,6 @@ targetTemplates:
       - sdk: NotificationCenter.framework
       - sdk: QuickLook.framework
       - package: Defaults
-      - package: OrderedCollections
     sources: 
       - path: App
       - path: Model