StoreRef for AppGroups

DataKernel/Classes/Contracts/Refs/StoreRef.swift

@@ -9,17 +9,42 @@
 import Foundation
 
 public enum StoreRef: Equatable {
-    case named(String)
     case url(URL)
-
+    case named(String)
+    case namedInGroup(name: String, appGroup: String)
+
     public func location() -> URL {
         switch self {
-        case .url(let url): return url
-        case .named(let name): return Foundation.URL(fileURLWithPath: FileUtils.documents()).appendingPathComponent(name)
+        case let .url(url):
+            return url
+
+        case let .named(name):
+            return Foundation.URL(fileURLWithPath: FileUtils.documents()).appendingPathComponent(name)
+
+        case let .namedInGroup(name, appGroup):
+            let containerUrl = FileUtils.documents(in: appGroup)
+            guard let dbDirUrl = containerUrl?.appendingPathComponent(dataKernelPath) else {
+                assert(false)
+                return StoreRef.named(name).location()
+            }
+            return dbDirUrl.appendingPathComponent(name)
         }
-    }    
+    }
+
+    // NOTE: If we move the store from a local directory to a shared one, we'd like to know where to migrate it from
+    func previousLocation() -> URL? {
+        switch self {
+        case let .namedInGroup(name, _):
+            return StoreRef.named(name).location()
+
+        default:
+            return nil
+        }
+    }
 }
 
 public func == (lhs: StoreRef, rhs: StoreRef) -> Bool {
     return lhs.location() == rhs.location()
 }
+
+private let dataKernelPath = "DataKernel"

DataKernel/Classes/Helpers/FileUtils.swift

@@ -12,4 +12,8 @@ class FileUtils {
     static func documents() -> String {
         return NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0]
     }
+
+    static func documents(in appGroup: String) -> URL? {
+        return FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: appGroup)
+    }
 }

DataKernelTests/Classes/Helpers/FileUtilsTests.swift

@@ -16,5 +16,20 @@ class FileUtilsTests: XCTestCase {
 
         XCTAssertEqual(path, NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0], "should return the proper documents directory")
     }
-
+
+//    NOTE: disabled because for using app groups there should be a capability with entitlements, but for public project it is impossible
+//    NOTE: you can test such thing in your own project
+//    func testProperPathInAppGroup() {
+//        guard let url = FileUtils.documents(in: "group") else {
+//            XCTAssert(false, "url should be set")
+//            return
+//        }
+//
+//        guard let expected = FileManager.default.containerURL(forSecurityApplicationGroupIdentifier: "group") else {
+//            XCTAssert(false, "expected should be set")
+//            return
+//        }
+//
+//        XCTAssertEqual(url, expected, "should return the proper documents directory in app group 'group'")
+//    }
 }