migration tests

LeStorage.xcodeproj/project.pbxproj

@@ -22,6 +22,7 @@
 		C4A47D6B2B71244100ADC637 /* Collection+Extension.swift in Sources */ = {isa = PBXBuildFile; fileRef = C4A47D6A2B71244100ADC637 /* Collection+Extension.swift */; };
 		C4A47D6D2B71364600ADC637 /* ModelObject.swift in Sources */ = {isa = PBXBuildFile; fileRef = C4A47D6C2B71364600ADC637 /* ModelObject.swift */; };
 		C4A47D6F2B7154F600ADC637 /* README.md in Resources */ = {isa = PBXBuildFile; fileRef = C4A47D6E2B7154F600ADC637 /* README.md */; };
+		C4A47D812B7665AD00ADC637 /* Migration.swift in Sources */ = {isa = PBXBuildFile; fileRef = C4A47D802B76658F00ADC637 /* Migration.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -51,6 +52,7 @@
 		C4A47D6A2B71244100ADC637 /* Collection+Extension.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Collection+Extension.swift"; sourceTree = "<group>"; };
 		C4A47D6C2B71364600ADC637 /* ModelObject.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ModelObject.swift; sourceTree = "<group>"; };
 		C4A47D6E2B7154F600ADC637 /* README.md */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = net.daringfireball.markdown; path = README.md; sourceTree = SOURCE_ROOT; };
+		C4A47D802B76658F00ADC637 /* Migration.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Migration.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -102,6 +104,7 @@
 				C425D4572B6D2519002A7B48 /* Store.swift */,
 				C4A47D642B6E92FE00ADC637 /* Storable.swift */,
 				C4A47D4E2B6D280200ADC637 /* StoredCollection.swift */,
+				C4A47D822B7665BC00ADC637 /* Wip */,
 				C4A47D582B6D352900ADC637 /* Utils */,
 			);
 			path = LeStorage;
@@ -126,6 +129,14 @@
 			path = Utils;
 			sourceTree = "<group>";
 		};
+		C4A47D822B7665BC00ADC637 /* Wip */ = {
+			isa = PBXGroup;
+			children = (
+				C4A47D802B76658F00ADC637 /* Migration.swift */,
+			);
+			path = Wip;
+			sourceTree = "<group>";
+		};
 /* End PBXGroup section */
 
 /* Begin PBXHeadersBuildPhase section */
@@ -244,6 +255,7 @@
 				C4A47D652B6E92FE00ADC637 /* Storable.swift in Sources */,
 				C4A47D6D2B71364600ADC637 /* ModelObject.swift in Sources */,
 				C4A47D4F2B6D280200ADC637 /* StoredCollection.swift in Sources */,
+				C4A47D812B7665AD00ADC637 /* Migration.swift in Sources */,
 				C4A47D672B6FF83A00ADC637 /* ApiCall.swift in Sources */,
 				C425D4582B6D2519002A7B48 /* Store.swift in Sources */,
 				C4A47D6B2B71244100ADC637 /* Collection+Extension.swift in Sources */,

LeStorage/ApiCall.swift

@@ -28,7 +28,7 @@ class ApiCall<T : Storable> : ModelObject, Storable, SomeCall {
     var dataId: String
     
     /// The content of the call
-    var body: Data
+    var body: String
     
     /// The number of times the call has been executed
     var attemptsCount: Int = 0
@@ -36,7 +36,7 @@ class ApiCall<T : Storable> : ModelObject, Storable, SomeCall {
     /// The date of the last execution
     var lastAttemptDate: Date = Date()
     
-    init(url: String, method: String, dataId: String, body: Data) {
+    init(url: String, method: String, dataId: String, body: String) {
         self.url = url
         self.method = method
         self.dataId = dataId

LeStorage/Services.swift

@@ -109,9 +109,9 @@ class Services {
     }
     
     fileprivate func _createCall<T : Storable>(method: Method, instance: T) throws -> ApiCall<T> {
-        let data = try instance.jsonData()
+        let jsonString = try instance.jsonString()
         let url = self._baseURL + T.resourceName() + "/"
-        return ApiCall(url: url, method: method.rawValue, dataId: String(instance.id), body: data)
+        return ApiCall(url: url, method: method.rawValue, dataId: String(instance.id), body: jsonString)
     }
     
     func runApiCall<T : Storable>(_ apiCall: ApiCall<T>) async throws -> T {
@@ -130,7 +130,7 @@ class Services {
         }
         var request = URLRequest(url: url)
         request.httpMethod = apiCall.method
-        request.httpBody = apiCall.body
+        request.httpBody = apiCall.body.data(using: .utf8)
         request.setValue("application/json", forHTTPHeaderField: "Content-Type")
         return request
     }

LeStorage/Storable.swift

@@ -18,4 +18,8 @@ extension Storable {
         return Store.main.findById(id)
     }
  
+    static func fileName() -> String {
+        return self.resourceName() + ".json"
+    }
+    
 }

LeStorage/Store.swift

@@ -35,21 +35,22 @@ public class Store {
     fileprivate var _collections: [String : any SomeCollection] = [:]
     fileprivate var _apiCallsCollections: [String : any SomeCollection] = [:]
     
-//    fileprivate var _apiCallTimers: [String: Timer] = [:]
+    fileprivate var _migrations: [SomeMigration] = []
+    
+    fileprivate lazy var _migrationCollection: StoredCollection<MigrationHistory> = { StoredCollection(synchronized: false, store: Store.main, asynchronousIO: false)
+    }()
     
     public init() { }
     
     public func registerCollection<T : Storable>(synchronized: Bool) -> StoredCollection<T> {
         
         // register collection
-        let collection = StoredCollection<T>(synchronized: synchronized, store: self, loadCompletion: { _ in
-            
-        })
+        let collection = StoredCollection<T>(synchronized: synchronized, store: Store.main, loadCompletion: nil)
         self._collections[T.resourceName()] = collection
         
         if synchronized { // register additional collection for api calls
-            let apiCallCollection = StoredCollection<ApiCall<T>>(synchronized: false, store: self, loadCompletion: { apiCallCollection in
-                self._reloadTimers(collection: apiCallCollection)
+            let apiCallCollection = StoredCollection<ApiCall<T>>(synchronized: false, store: Store.main, loadCompletion: { apiCallCollection in
+                self._rescheduleCalls(collection: apiCallCollection)
             })
             self._apiCallsCollections[T.resourceName()] = apiCallCollection
         }
@@ -88,9 +89,47 @@ public class Store {
         try self.collection().deleteDependencies(items)
     }
     
+    // MARK: - Migration
+    
+    public func addMigration(_ migration: SomeMigration) {
+        self._migrations.append(migration)
+    }
+    
+    func performMigrationIfNecessary<T : Storable>(_ collection: StoredCollection<T>) async throws {
+        
+        // Check for migrations
+        let migrations = self._migrations.filter { $0.resourceName == T.resourceName() }
+        if migrations.isEmpty { return }
+        
+        // Check for applied migrations
+        var version: Int = -1
+        var performedMigration: MigrationHistory? = self._migrationCollection.first(where: { $0.resourceName == T.resourceName() })
+        if let performedMigration {
+            version = Int(performedMigration.version)
+        }
+        
+        // Apply necessary migrations
+        let applicableMigrations = migrations.filter { $0.version > version }
+            .sorted(keyPath: \.version)
+        for migration in applicableMigrations {
+            
+            Logger.log("Start migration for \(migration.resourceName), version: \(migration.version)")
+            
+            try migration.migrate(synchronized: collection.synchronized)
+
+            if let performedMigration {
+                performedMigration.version = migration.version
+            } else {
+                performedMigration = MigrationHistory(version: migration.version, resourceName: migration.resourceName)
+            }
+            
+            self._migrationCollection.addOrUpdate(instance: performedMigration!)
+        }
+    }
+    
     // MARK: - Api call rescheduling
     
-    fileprivate func _reloadTimers<T : Storable>(collection: StoredCollection<ApiCall<T>>) {
+    fileprivate func _rescheduleCalls<T : Storable>(collection: StoredCollection<ApiCall<T>>) {
         for apiCall in collection {
             self.startCallsRescheduling(apiCall: apiCall)
         }

LeStorage/StoredCollection.swift

@@ -32,13 +32,9 @@ public class StoredCollection<T : Storable> : RandomAccessCollection, SomeCollec
     /// The reference to the Store
     fileprivate var _store: Store
     
-    fileprivate var loadCompletion: (StoredCollection<T>) -> ()
-    
-    /// Returns the default filename for the collection
-    fileprivate var _fileName: String {
-        return T.resourceName() + ".json"
-    }
-    
+    /// Notifies the closure when the loading is done
+    fileprivate var loadCompletion: ((StoredCollection<T>) -> ())? = nil
+        
     /// Indicates whether the collection has changed, thus requiring a write operation
     fileprivate var _hasChanged: Bool = false {
         didSet {
@@ -52,47 +48,54 @@ public class StoredCollection<T : Storable> : RandomAccessCollection, SomeCollec
         }
     }
     
-    init(synchronized: Bool, store: Store, loadCompletion: @escaping (StoredCollection<T>) -> ()) {
+    fileprivate var asynchronousIO: Bool = true
+    
+    init(synchronized: Bool, store: Store, asynchronousIO: Bool = true, loadCompletion: ((StoredCollection<T>) -> ())? = nil) {
         self.synchronized = synchronized
+        self.asynchronousIO = asynchronousIO
         self._store = store
         self.loadCompletion = loadCompletion
         self._load()
     }
+        
+    // MARK: - Loading
     
-    /// Launches a load operation if the file exists
+    /// Migrates if necessary and asynchronously decodes the json file
     fileprivate func _load() {
         do {
-            let url = try FileUtils.directoryURLForFileName(self._fileName)
+            let url = try FileUtils.directoryURLForFileName(T.fileName())
             if FileManager.default.fileExists(atPath: url.path()) {
-                self._loadAsync()
-            } else {
-                try? self.loadDataFromServer()
+                
+                if self.asynchronousIO {
+                    Task(priority: .high) {
+                        try await Store.main.performMigrationIfNecessary(self)
+                        try self._decodeJSONFile()
+                    }
+                } else {
+                    try self._decodeJSONFile()
+                }
+
             }
+//            else {
+//                try? self.loadDataFromServer()
+//            }
         } catch {
             Logger.log(error)
         }
         
     }
-    
-    /// Loads asynchronously into memory the objects contained inside the collection file
-    fileprivate func _loadAsync() {
-        DispatchQueue(label: "lestorage.queue.read", qos: .background).async {
-            do {
-                let jsonString = try FileUtils.readDocumentFile(fileName: self._fileName)
-                if let decoded: [T] = try jsonString.decodeArray() {
-                    DispatchQueue.main.sync {
-                        Logger.log("loaded \(self._fileName) with \(decoded.count) items")
-                        self.items = decoded
-                        self.loadCompletion(self)
-                        
-                        NotificationCenter.default.post(name: NSNotification.Name.CollectionDidLoad, object: self)
-                    }
-                }
-            } catch {
-                Logger.error(error) // TODO how to notify the main project
+        
+    fileprivate func _decodeJSONFile() throws {
+        let jsonString = try FileUtils.readDocumentFile(fileName: T.fileName())
+        if let decoded: [T] = try jsonString.decodeArray() {
+            DispatchQueue.main.sync {
+                Logger.log("loaded \(T.fileName()) with \(decoded.count) items")
+                self.items = decoded
+                self.loadCompletion?(self)
+                
+                NotificationCenter.default.post(name: NSNotification.Name.CollectionDidLoad, object: self)
             }
         }
-
     }
     
     public func loadDataFromServer() throws {
@@ -108,6 +111,8 @@ public class StoredCollection<T : Storable> : RandomAccessCollection, SomeCollec
         }
     }
     
+    // MARK: - Basic operations
+    
     /// Adds or updates the provided instance inside the collection
     /// Adds it if its id is not found, and otherwise updates it
     public func addOrUpdate(instance: T) {
@@ -136,6 +141,16 @@ public class StoredCollection<T : Storable> : RandomAccessCollection, SomeCollec
         self._sendDeletionIfNecessary(instance)
     }
     
+    public func batchInsert(_ sequence: any Sequence<T>) {
+        defer {
+            self._hasChanged = true
+        }
+        self.items.append(contentsOf: sequence)
+        for instance in sequence {
+            self._sendUpdateIfNecessary(instance)
+        }
+    }
+    
     /// Returns the instance corresponding to the provided [id]
     public func findById(_ id: String) -> T? {
         return self.items.first(where: { $0.id == id })
@@ -169,18 +184,22 @@ public class StoredCollection<T : Storable> : RandomAccessCollection, SomeCollec
     
     /// Schedules a write operation
     fileprivate func _scheduleWrite() {
-        self._write()
+        if self.asynchronousIO {
+            DispatchQueue(label: "lestorage.queue.write", qos: .utility).async {
+                self._write()
+            }
+        } else {
+            self._write()
+        }
     }
     
     /// Writes all the items as a json array inside a file
     fileprivate func _write() {
-        DispatchQueue(label: "lestorage.queue.write", qos: .background).async {
-            do {
-                let jsonString = try self.items.jsonString()
-                let _ = try FileUtils.writeToDocumentDirectory(content: jsonString, fileName: self._fileName)
-            } catch {
-                Logger.error(error) // TODO how to notify the main project
-            }
+        do {
+            let jsonString: String = try self.items.jsonString()
+            let _ = try FileUtils.writeToDocumentDirectory(content: jsonString, fileName: T.fileName())
+        } catch {
+            Logger.error(error) // TODO how to notify the main project
         }
     }
     

LeStorage/Utils/Collection+Extension.swift

@@ -11,7 +11,11 @@ extension Array {
     
     func sorted<V : Comparable>(keyPath: KeyPath<Element, V>, ascending: Bool = true) -> [Element] {
         return self.sorted { e1, e2 in
-            return e1[keyPath: keyPath] > e2[keyPath: keyPath]
+            if ascending {
+                return e1[keyPath: keyPath] < e2[keyPath: keyPath]
+            } else {
+                return e1[keyPath: keyPath] > e2[keyPath: keyPath]
+            }
         }
     }
     

LeStorage/Wip/Migration.swift

@@ -0,0 +1,85 @@
+//
+//  Migration.swift
+//  LeStorage
+//
+//  Created by Laurent Morvillier on 07/02/2024.
+//
+
+import Foundation
+
+public protocol MigrationSource : Storable {
+    associatedtype Destination : Storable
+    func migrate() -> Destination
+}
+
+public protocol SomeMigration {
+    func migrate(synchronized: Bool) throws
+    var version: UInt { get }
+    var resourceName: String { get }
+}
+
+public class Migration<S : MigrationSource, D : Storable> : SomeMigration where S.Destination == D {
+    
+    public var version: UInt
+    
+    public var resourceName: String {
+        return S.resourceName()
+    }
+
+    public init(version: UInt) {
+        self.version = version
+    }
+    
+    public func migrate(synchronized: Bool) throws {
+        try self._migrateMainCollection()
+        if synchronized {
+            try self._migrateApiCallsCollection()
+        }
+    }
+    
+    fileprivate func _migrateMainCollection() throws {
+        let jsonString = try FileUtils.readDocumentFile(fileName: S.fileName())
+        if let decoded: [S] = try jsonString.decodeArray() {
+            
+            let migratedObjects: [D] = decoded.map { $0.migrate() }
+            
+            let jsonString: String = try migratedObjects.jsonString()
+            let _ = try FileUtils.writeToDocumentDirectory(content: jsonString, fileName: D.fileName())
+        }
+    }
+    
+    fileprivate func _migrateApiCallsCollection() throws {
+        let jsonString = try FileUtils.readDocumentFile(fileName: ApiCall<S>.fileName())
+        if let apiCalls: [ApiCall<S>] = try jsonString.decodeArray() {
+            
+            let migratedCalls = try apiCalls.map { apiCall in
+                if let source: S = try apiCall.body.decode() {
+                    let migrated: D = source.migrate()
+                    apiCall.body = try migrated.jsonString()
+                }
+                return apiCall
+            }
+            
+            let jsonString = try migratedCalls.jsonString()
+            let _ = try FileUtils.writeToDocumentDirectory(content: jsonString, fileName: ApiCall<D>.fileName())
+
+            Logger.log("Ended _migrateApiCallsCollection: \(jsonString)")
+        }
+    }
+    
+}
+
+class MigrationHistory: ModelObject, Storable {
+    
+    public static func resourceName() -> String { "migration_history" }
+
+    public var id: String = Store.randomId()
+    public var version: UInt
+    public var resourceName: String
+    
+    init(version: UInt, resourceName: String) {
+        self.version = version
+        self.resourceName = resourceName
+    }
+    
+}