[SR-10374] URLCache: init method and first time sqlite database setup implemented

Foundation.xcodeproj/project.pbxproj

@@ -74,6 +74,7 @@
 		15FF00CC22934AD7004AD205 /* libCFURLSessionInterface.a in Frameworks */ = {isa = PBXBuildFile; fileRef = 15FF00CA229348F2004AD205 /* libCFURLSessionInterface.a */; };
 		15FF00CE22934B78004AD205 /* module.map in Headers */ = {isa = PBXBuildFile; fileRef = 15FF00CD22934B49004AD205 /* module.map */; settings = {ATTRIBUTES = (Public, ); }; };
 		231503DB1D8AEE5D0061694D /* TestDecimal.swift in Sources */ = {isa = PBXBuildFile; fileRef = 231503DA1D8AEE5D0061694D /* TestDecimal.swift */; };
+		25EB1806223334D30053EE59 /* TestURLCache.swift in Sources */ = {isa = PBXBuildFile; fileRef = 25EB1805223334D30053EE59 /* TestURLCache.swift */; };
 		294E3C1D1CC5E19300E4F44C /* TestNSAttributedString.swift in Sources */ = {isa = PBXBuildFile; fileRef = 294E3C1C1CC5E19300E4F44C /* TestNSAttributedString.swift */; };
 		2EBE67A51C77BF0E006583D5 /* TestDateFormatter.swift in Sources */ = {isa = PBXBuildFile; fileRef = 2EBE67A31C77BF05006583D5 /* TestDateFormatter.swift */; };
 		3E55A2331F52463B00082000 /* TestUnit.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3E55A2321F52463B00082000 /* TestUnit.swift */; };
@@ -646,6 +647,7 @@
 		15FF00CD22934B49004AD205 /* module.map */ = {isa = PBXFileReference; lastKnownFileType = "sourcecode.module-map"; name = module.map; path = CoreFoundation/URL.subproj/module.map; sourceTree = SOURCE_ROOT; };
 		22B9C1E01C165D7A00DECFF9 /* TestDate.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TestDate.swift; sourceTree = "<group>"; };
 		231503DA1D8AEE5D0061694D /* TestDecimal.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TestDecimal.swift; sourceTree = "<group>"; };
+		25EB1805223334D30053EE59 /* TestURLCache.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TestURLCache.swift; sourceTree = "<group>"; };
 		294E3C1C1CC5E19300E4F44C /* TestNSAttributedString.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TestNSAttributedString.swift; sourceTree = "<group>"; };
 		2EBE67A31C77BF05006583D5 /* TestDateFormatter.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = TestDateFormatter.swift; sourceTree = "<group>"; };
 		3E55A2321F52463B00082000 /* TestUnit.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = TestUnit.swift; sourceTree = "<group>"; };
@@ -1777,6 +1779,7 @@
 				03B6F5831F15F339004F25AF /* TestURLProtocol.swift */,
 				3E55A2321F52463B00082000 /* TestUnit.swift */,
 				7D8BD738225ED1480057CF37 /* TestMeasurement.swift */,
+				25EB1805223334D30053EE59 /* TestURLCache.swift */,
 			);
 			name = Tests;
 			sourceTree = "<group>";
@@ -2834,6 +2837,7 @@
 				5B13B33E1C582D4C00651CE2 /* TestProcessInfo.swift in Sources */,
 				5B13B33F1C582D4C00651CE2 /* TestPropertyListSerialization.swift in Sources */,
 				5B13B32C1C582D4C00651CE2 /* TestDate.swift in Sources */,
+				25EB1806223334D30053EE59 /* TestURLCache.swift in Sources */,
 				C7DE1FCC21EEE67200174F35 /* TestUUID.swift in Sources */,
 				231503DB1D8AEE5D0061694D /* TestDecimal.swift in Sources */,
 				7900433C1CACD33E00ECCBF1 /* TestNSPredicate.swift in Sources */,

Foundation/URLCache.swift

@@ -128,6 +128,12 @@ open class CachedURLResponse : NSObject, NSSecureCoding, NSCopying {
 
 open class URLCache : NSObject {
 
+    private static let sharedSyncQ = DispatchQueue(label: "org.swift.URLCache.sharedSyncQ")
+    private static var sharedCache: URLCache?
+
+    private let syncQ = DispatchQueue(label: "org.swift.URLCache.syncQ")
+    private var persistence: _CachePersistence?
+
     /*! 
         @method sharedURLCache
         @abstract Returns the shared URLCache instance.
@@ -147,13 +153,37 @@ open class URLCache : NSObject {
     */
     open class var shared: URLCache {
         get {
-            NSUnimplemented()
+            return sharedSyncQ.sync {
+                if let cache = sharedCache {
+                    return cache
+                } else {
+                    guard var cacheDirectoryUrl = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first else {
+                        fatalError("Unable to find cache directory")
+                    }
+
+                    let fourMegaByte = 4 * 1024 * 1024
+                    let twentyMegaByte = 20 * 1024 * 1024
+                    cacheDirectoryUrl.appendPathComponent(ProcessInfo.processInfo.processName)
+                    let cache = URLCache(memoryCapacity: fourMegaByte, diskCapacity: twentyMegaByte, diskPath: cacheDirectoryUrl.path)
+                    sharedCache = cache
+                    cache.persistence?.setupCacheDirectory()
+                    return cache
+                }
+            }
         }
         set {
-            NSUnimplemented()
+            guard newValue !== sharedCache else { return }
+
+            sharedSyncQ.sync {
+                sharedCache = newValue
+                newValue.persistence?.setupCacheDirectory()
+            }
         }
     }
 
+    private var allCaches: [String: CachedURLResponse] = [:]
+    private var cacheSizeInMemory: Int = 0
+
     /*! 
         @method initWithMemoryCapacity:diskCapacity:diskPath:
         @abstract Initializes an URLCache with the given capacity and
@@ -167,7 +197,17 @@ open class URLCache : NSObject {
         @result an initialized URLCache, with the given capacity, backed
         by disk.
     */
-    public init(memoryCapacity: Int, diskCapacity: Int, diskPath path: String?) { NSUnimplemented() }
+    public init(memoryCapacity: Int, diskCapacity: Int, diskPath path: String?) {
+        self.memoryCapacity = memoryCapacity
+        self.diskCapacity = diskCapacity
+
+        // As per the function of URLCache, `diskCapacity` of `0` is assumed as no-persistence.
+        if diskCapacity > 0, let _path = path {
+            self.persistence = _CachePersistence(path: _path)
+        }
+
+        super.init()
+    }
 
     /*! 
         @method cachedResponseForRequest:
@@ -238,7 +278,9 @@ open class URLCache : NSObject {
         usage of the in-memory cache. 
         @result the current usage of the in-memory cache of the receiver.
     */
-    open var currentMemoryUsage: Int { NSUnimplemented() }
+    open var currentMemoryUsage: Int {
+        return self.syncQ.sync { self.cacheSizeInMemory }
+    }
 
     /*! 
         @method currentDiskUsage
@@ -248,11 +290,102 @@ open class URLCache : NSObject {
         usage of the on-disk cache. 
         @result the current usage of the on-disk cache of the receiver.
     */
-    open var currentDiskUsage: Int { NSUnimplemented() }
+    open var currentDiskUsage: Int {
+        return self.syncQ.sync { self.persistence?.cacheSizeInDisk ?? 0 }
+    }
+
 }
 
 extension URLCache {
     public func storeCachedResponse(_ cachedResponse: CachedURLResponse, for dataTask: URLSessionDataTask) { NSUnimplemented() }
     public func getCachedResponse(for dataTask: URLSessionDataTask, completionHandler: (CachedURLResponse?) -> Void) { NSUnimplemented() }
     public func removeCachedResponse(for dataTask: URLSessionDataTask) { NSUnimplemented() }
 }
+
+fileprivate struct _CachePersistence {
+
+    let path: String
+
+    // FIXME: Create a stored property
+    // Update this value as the cache added and evicted
+    var cacheSizeInDisk: Int {
+        do {
+            let subFiles = try FileManager.default.subpathsOfDirectory(atPath: path)
+            var total: Int = 0
+            for fileName in subFiles {
+                let attributes = try FileManager.default.attributesOfItem(atPath: path.appending(fileName))
+                total += (attributes[.size] as? Int) ?? 0
+            }
+            return total
+        } catch {
+            return 0
+        }
+    }
+
+    func setupCacheDirectory() {
+        try? FileManager.default.createDirectory(atPath: path, withIntermediateDirectories: true)
+    }
+
+    func saveCachedResponse(_ response: CachedURLResponse, for request: URLRequest) {
+        do {
+            if let archivedData = try? NSKeyedArchiver.archivedData(withRootObject: response, requiringSecureCoding: true),
+                let fileIdentifier = request.cacheFileIdentifier {
+                let cacheFileURL = urlForFileIdentifier(fileIdentifier)
+                try archivedData.write(to: cacheFileURL)
+            }
+        } catch {
+            fatalError("Unable to save cache data: \(error.localizedDescription)")
+        }
+    }
+
+    func cachedResponse(for request: URLRequest) -> CachedURLResponse? {
+        guard let fileIdentifier = request.cacheFileIdentifier else {
+            return nil
+        }
+
+        let url = urlForFileIdentifier(fileIdentifier)
+        guard let data = try? Data(contentsOf: url),
+            let response = try? NSKeyedUnarchiver.unarchivedObject(ofClasses:[CachedURLResponse.self], from: data) as? CachedURLResponse else {
+            return nil
+        }
+
+        return response
+    }
+
+    private func urlForFileIdentifier(_ identifier: String) -> URL {
+        return URL(fileURLWithPath: path).appendingPathComponent(identifier)
+    }
+
+}
+
+extension URLRequest {
+
+    fileprivate var cacheFileIdentifier: String? {
+        guard let scheme = self.url?.scheme, scheme == "http" || scheme == "https",
+            let method = httpMethod, !method.isEmpty,
+            let urlString = url?.absoluteString else {
+                return nil
+        }
+
+        var hashString = "\(abs(method.hashValue))-\(abs(urlString.hashValue))"
+
+        if let userAgent = self.allHTTPHeaderFields?["User-Agent"], !userAgent.isEmpty {
+            hashString.append("\(abs(userAgent.hashValue))")
+        }
+
+        if let acceptLanguage = self.allHTTPHeaderFields?["Accept-Language"], !acceptLanguage.isEmpty {
+            hashString.append("-\(abs(acceptLanguage.hashValue))")
+        }
+
+        if let range = self.allHTTPHeaderFields?["Range"], !range.isEmpty {
+            hashString.append("-\(abs(range.hashValue))")
+        }
+
+        if let data = self.httpBody, !data.isEmpty {
+            hashString.append("-\(abs(data.hashValue))")
+        }
+
+        return hashString
+    }
+
+}

TestFoundation/TestURLCache.swift

@@ -0,0 +1,42 @@
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+
+class TestURLCache: XCTestCase {
+
+    static var allTests: [(String, (TestURLCache) -> () throws -> Void)] {
+        return [
+            ("test_cacheFileAndDirectorySetup", test_cacheFileAndDirectorySetup),
+        ]
+    }
+
+    private var cacheDirectoryPath: String {
+        guard var cacheDirectoryUrl = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first else {
+            fatalError("Unable to find cache directory")
+        }
+
+        cacheDirectoryUrl.appendPathComponent(ProcessInfo.processInfo.processName)
+        return cacheDirectoryUrl.path
+    }
+
+    func test_cacheFileAndDirectorySetup() {
+        // Test default directory
+        let _ = URLCache.shared
+        XCTAssertTrue(FileManager.default.fileExists(atPath: cacheDirectoryPath))
+
+        let fourMegaByte = 4 * 1024 * 1024
+        let twentyMegaByte = 20 * 1024 * 1024
+
+        // Test with a custom directory
+        let newPath = cacheDirectoryPath + ".test_cacheFileAndDirectorySetup/"
+        URLCache.shared = URLCache(memoryCapacity: fourMegaByte, diskCapacity: twentyMegaByte, diskPath: newPath)
+        XCTAssertTrue(FileManager.default.fileExists(atPath: newPath))
+        XCTAssertTrue(FileManager.default.fileExists(atPath: cacheDirectoryPath))
+    }
+
+}

TestFoundation/main.swift

@@ -81,6 +81,7 @@ var allTestCases = [
     testCase(TestTimer.allTests),
     testCase(TestTimeZone.allTests),
     testCase(TestURL.allTests),
+    testCase(TestURLCache.allTests),
     testCase(TestURLComponents.allTests),
     testCase(TestURLCredential.allTests),
     testCase(TestURLProtectionSpace.allTests),