Fixed SaveDb for CachingFileStorage and target file not existing

-> + Tests
First, very simple implementation of ChangingFileStorage in KP2A App (preliminary)

src/Kp2aBusinessLogic/Io/CachingFileStorage.cs

@@ -20,7 +20,7 @@ namespace keepass2android.Io
 		/// </summary>
 		/// <param name="ioc">The file which we tried to write</param>
 		/// <param name="e">The exception why the remote file couldn't be updated</param>
-		void CouldntSaveToRemote(IOConnectionInfo ioc, Exception e);
+		void CouldntSaveToRemote(IOConnectionInfo ioc, Exception ex);
 
 		/// <summary>
 		/// Called when only the local file could be opened during an open operation.

src/Kp2aBusinessLogic/database/edit/SaveDB.cs

@@ -99,12 +99,10 @@ namespace keepass2android
 					}
 					
 
-
-
 					if (
 						(_streamForOrigFile != null)
 						|| fileStorage.CheckForFileChangeFast(ioc, _app.GetDb().LastFileVersion)  //first try to use the fast change detection
-						|| (FileHashChanged(ioc, _app.GetDb().KpDatabase.HashOfFileOnDisk)) //if that fails, hash the file and compare:
+						|| (FileHashChanged(ioc, _app.GetDb().KpDatabase.HashOfFileOnDisk) == FileHashChange.Changed) //if that fails, hash the file and compare:
 						)
 					{
 
@@ -243,14 +241,26 @@ namespace keepass2android
 			_app.GetDb().LastFileVersion = fileStorage.GetCurrentFileVersionFast(ioc);
 		}
 
-		public byte[] HashFile(IOConnectionInfo iocFile)
+		public byte[] HashOriginalFile(IOConnectionInfo iocFile)
 		{
 			if (iocFile == null) { Debug.Assert(false); return null; } // Assert only
 
 			Stream sIn;
 			try
 			{
-				sIn = _app.GetFileStorage(iocFile).OpenFileForRead(iocFile);
+				IFileStorage fileStorage = _app.GetFileStorage(iocFile);
+				CachingFileStorage cachingFileStorage = fileStorage as CachingFileStorage;
+				if (cachingFileStorage != null)
+				{
+					string hash;
+					cachingFileStorage.GetRemoteDataAndHash(iocFile, out hash);
+					return MemUtil.HexStringToByteArray(hash);
+				}
+				else
+				{
+					sIn = fileStorage.OpenFileForRead(iocFile);	
+				}
+				
 				if (sIn == null) throw new FileNotFoundException();
 			}
 			catch (Exception) { return null; }
@@ -267,10 +277,20 @@ namespace keepass2android
 			return pbHash;
 		}
 
-		private bool FileHashChanged(IOConnectionInfo ioc, byte[] hashOfFileOnDisk)
+		enum FileHashChange
+		{
+			Equal,
+			Changed,
+			FileNotAvailable
+		}
+
+		private FileHashChange FileHashChanged(IOConnectionInfo ioc, byte[] hashOfFileOnDisk)
 		{
 			StatusLogger.UpdateSubMessage(_app.GetResourceString(UiStringKey.CheckingTargetFileForChanges));
-			return !MemUtil.ArraysEqual(HashFile(ioc), hashOfFileOnDisk);
+			byte[] fileHash = HashOriginalFile(ioc);
+			if (fileHash == null)
+				return FileHashChange.FileNotAvailable;
+			return MemUtil.ArraysEqual(fileHash, hashOfFileOnDisk) ? FileHashChange.Equal : FileHashChange.Changed;
 		}
 
 		

src/Kp2aUnitTests/Kp2aUnitTests.csproj

@@ -71,6 +71,7 @@
     <Compile Include="TestLoadDbCredentials.cs" />
     <Compile Include="TestCachingFileStorage.cs" />
     <Compile Include="TestSaveDb.cs" />
+    <Compile Include="TestSaveDbCached.cs" />
     <Compile Include="TestSynchronizeCachedDatabase.cs" />
   </ItemGroup>
   <ItemGroup>

src/Kp2aUnitTests/MainActivity.cs

@@ -19,8 +19,10 @@ namespace Kp2aUnitTests
             TestRunner runner = new TestRunner();
             // Run all tests from this assembly
             runner.AddTests(Assembly.GetExecutingAssembly());
-			//runner.AddTests(new List<Type> { typeof(TestSynchronizeCachedDatabase) });
+			//runner.AddTests(new List<Type> { typeof(TestSaveDbCached) });
-			//runner.AddTests(new List<Type> { typeof(TestLoadDb) });}}
+			//runner.AddTests(typeof(TestSaveDbCached).GetMethod("TestLoadEditSaveWhenModified"));
+			
+			//runner.AddTests(new List<Type> { typeof(TestSaveDb) });
 			//runner.AddTests(new List<Type> { typeof(TestCachingFileStorage) });
 			//runner.AddTests(typeof(TestCachingFileStorage).GetMethod("TestSaveToRemote"));
 			//runner.AddTests(typeof(TestLoadDb).GetMethod("TestLoadKdbpWithPasswordOnly"));

src/Kp2aUnitTests/TestCachingFileStorage.cs

@@ -191,8 +191,6 @@ namespace Kp2aUnitTests
 
 			Assert.IsTrue(_testCacheSupervisor.CouldntOpenFromRemoteCalled);
 			Assert.IsFalse(_testCacheSupervisor.CouldntSaveToRemoteCalled);
-			Assert.IsFalse(_testCacheSupervisor.RestoredRemoteCalled);
-
 			
 		}
 

src/Kp2aUnitTests/TestSaveDb.cs

@@ -126,6 +126,35 @@ namespace Kp2aUnitTests
 		}
 
 
+		[TestMethod]
+		public void TestLoadEditSaveWithWriteBecauseTargetNotExists()
+		{
+			//create the default database:
+			IKp2aApp app = SetupAppWithDefaultDatabase();
+			//save it and reload it so we have a base version
+			SaveDatabase(app);
+			app = LoadDatabase(DefaultFilename, DefaultPassword, DefaultKeyfile);
+			
+			//modify the database by adding a group:
+			app.GetDb().KpDatabase.RootGroup.AddGroup(new PwGroup(true, true, "TestGroup", PwIcon.Apple), true);
+
+			//delete the file:
+			File.Delete(DefaultFilename);
+
+			//save the database:
+			SaveDatabase(app);
+
+			//make sure no question was asked
+			Assert.AreEqual(null, ((TestKp2aApp)app).LastYesNoCancelQuestionTitle);
+
+			//load database to a new app instance:
+			IKp2aApp resultApp = LoadDatabase(DefaultFilename, DefaultPassword, DefaultKeyfile);
+
+			//ensure the file was saved:
+			AssertDatabasesAreEqual(app.GetDb().KpDatabase, resultApp.GetDb().KpDatabase);
+
+		}
+
 		[TestMethod]
 		public void TestLoadEditSaveWithSyncOverwriteBecauseOfNoCheck()
 		{

src/Kp2aUnitTests/TestSaveDbCached.cs

@@ -0,0 +1,148 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+
+using Android.App;
+using Android.Content;
+using Android.OS;
+using Android.Runtime;
+using Android.Views;
+using Android.Widget;
+using KeePassLib;
+using KeePassLib.Serialization;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using keepass2android;
+using keepass2android.Io;
+
+namespace Kp2aUnitTests
+{
+	[TestClass]
+	class TestSaveDbCached: TestBase
+	{
+		private TestCacheSupervisor _testCacheSupervisor = new TestCacheSupervisor();
+		private TestFileStorage _testFileStorage = new TestFileStorage();
+
+		protected override TestKp2aApp CreateTestKp2aApp()
+		{
+			TestKp2aApp app = base.CreateTestKp2aApp();
+			app.FileStorage = new CachingFileStorage(_testFileStorage, "/mnt/sdcard/kp2atest/cache/", _testCacheSupervisor);
+			return app;
+		}
+
+		[TestMethod]
+		public void TestLoadEditSave()
+		{
+			//create the default database:
+			IKp2aApp app = SetupAppWithDefaultDatabase();
+			IOConnection.DeleteFile(new IOConnectionInfo { Path = DefaultFilename });
+			//save it and reload it so we have a base version
+			SaveDatabase(app);
+			app = LoadDatabase(DefaultFilename, DefaultPassword, DefaultKeyfile);
+			//modify the database by adding a group:
+			app.GetDb().KpDatabase.RootGroup.AddGroup(new PwGroup(true, true, "TestGroup", PwIcon.Apple), true);
+			//save the database again:
+			SaveDatabase(app);
+			Assert.IsNull(((TestKp2aApp)app).LastYesNoCancelQuestionTitle);
+			Assert.IsFalse(_testCacheSupervisor.CouldntOpenFromRemoteCalled);
+			Assert.IsFalse(_testCacheSupervisor.CouldntSaveToRemoteCalled);
+
+			//load database to a new app instance:
+			IKp2aApp resultApp = LoadDatabase(DefaultFilename, DefaultPassword, DefaultKeyfile);
+
+			//ensure the change was saved:
+			AssertDatabasesAreEqual(app.GetDb().KpDatabase, resultApp.GetDb().KpDatabase);
+		}
+
+		[TestMethod]
+		public void TestLoadEditSaveWhenDeleted()
+		{
+			//create the default database:
+			IKp2aApp app = SetupAppWithDefaultDatabase();
+			IOConnection.DeleteFile(new IOConnectionInfo { Path = DefaultFilename });
+			//save it and reload it so we have a base version
+			SaveDatabase(app);
+			app = LoadDatabase(DefaultFilename, DefaultPassword, DefaultKeyfile);
+
+			//delete the file:
+			File.Delete(DefaultFilename);
+
+			//modify the database by adding a group:
+			app.GetDb().KpDatabase.RootGroup.AddGroup(new PwGroup(true, true, "TestGroup", PwIcon.Apple), true);
+			//save the database again:
+			SaveDatabase(app);
+			Assert.IsNull(((TestKp2aApp) app).LastYesNoCancelQuestionTitle);
+			Assert.IsFalse(_testCacheSupervisor.CouldntOpenFromRemoteCalled);
+			Assert.IsFalse(_testCacheSupervisor.CouldntSaveToRemoteCalled);
+
+			//load database to a new app instance:
+			IKp2aApp resultApp = LoadDatabase(DefaultFilename, DefaultPassword, DefaultKeyfile);
+
+			//ensure the change was saved:
+			AssertDatabasesAreEqual(app.GetDb().KpDatabase, resultApp.GetDb().KpDatabase);
+		}
+
+
+		[TestMethod]
+		public void TestLoadEditSaveWhenModified()
+		{
+			//create the default database:
+			IKp2aApp app = SetupAppWithDefaultDatabase();
+			IOConnection.DeleteFile(new IOConnectionInfo { Path = DefaultFilename });
+			//save it and reload it so we have a base version
+			SaveDatabase(app);
+			app = LoadDatabase(DefaultFilename, DefaultPassword, DefaultKeyfile);
+
+			foreach (var group in app.GetDb().KpDatabase.RootGroup.Groups)
+				Kp2aLog.Log("app c: " + group.Name);
+
+			//load once more:
+			var app2 = LoadDatabase(DefaultFilename, DefaultPassword, DefaultKeyfile);
+
+			//modifiy once:
+			PwGroup group2 = new PwGroup(true, true, "TestGroup2", PwIcon.Apple);
+			app2.GetDb().KpDatabase.RootGroup.AddGroup(group2, true);
+
+			foreach (var group in app.GetDb().KpDatabase.RootGroup.Groups)
+				Kp2aLog.Log("app b: " + group.Name);
+
+			SaveDatabase(app2);
+
+			foreach (var group in app.GetDb().KpDatabase.RootGroup.Groups)
+				Kp2aLog.Log("app d: " + group.Name);
+			Assert.IsNull(((TestKp2aApp)app).LastYesNoCancelQuestionTitle);
+			Assert.IsFalse(_testCacheSupervisor.CouldntOpenFromRemoteCalled);
+			Assert.IsFalse(_testCacheSupervisor.CouldntSaveToRemoteCalled);
+
+			//modify the database by adding a group:
+			PwGroup group1 = new PwGroup(true, true, "TestGroup", PwIcon.Apple);
+			app.GetDb().KpDatabase.RootGroup.AddGroup(group1, true);
+
+			foreach (var group in app.GetDb().KpDatabase.RootGroup.Groups)
+				Kp2aLog.Log("app a: " + group.Name);
+
+
+			//save the database again:
+			SaveDatabase(app);
+			Assert.AreEqual(((TestKp2aApp)app).LastYesNoCancelQuestionTitle, UiStringKey.TitleSyncQuestion);
+			Assert.IsFalse(_testCacheSupervisor.CouldntOpenFromRemoteCalled);
+			Assert.IsFalse(_testCacheSupervisor.CouldntSaveToRemoteCalled);
+			
+
+			//load database to a new app instance:
+			IKp2aApp resultApp = LoadDatabase(DefaultFilename, DefaultPassword, DefaultKeyfile);
+
+			app2.GetDb().KpDatabase.RootGroup.AddGroup(group1, true);
+			foreach (var group in app.GetDb().KpDatabase.RootGroup.Groups)
+				Kp2aLog.Log("app: "+group.Name);
+
+			foreach (var group in resultApp.GetDb().KpDatabase.RootGroup.Groups)
+				Kp2aLog.Log("resultApp: " + group.Name);
+
+			//ensure the change was saved:
+			AssertDatabasesAreEqual(app2.GetDb().KpDatabase, resultApp.GetDb().KpDatabase);
+
+		}
+	}
+}

src/keepass2android/app/App.cs

@@ -20,6 +20,7 @@ using Android.App;
 using Android.Content;
 using Android.OS;
 using Android.Runtime;
+using Android.Widget;
 using KeePassLib.Serialization;
 using Android.Preferences;
 using keepass2android.Io;
@@ -57,8 +58,8 @@ namespace keepass2android
 	/// <summary>
 	/// Main implementation of the IKp2aApp interface for usage in the real app.
 	/// </summary>
-    public class Kp2aApp: IKp2aApp
+    public class Kp2aApp: IKp2aApp, ICacheSupervisor
-    {
+	{
         public bool IsShutdown()
         {
             return _shutdown;
@@ -253,7 +254,13 @@ namespace keepass2android
 
 		public IFileStorage GetFileStorage(IOConnectionInfo iocInfo)
 		{
-			return new BuiltInFileStorage();
+			if (iocInfo.IsLocalFile())
+				return new BuiltInFileStorage();
+			else
+			{
+				//todo: check if desired
+				return new CachingFileStorage(new BuiltInFileStorage(), Application.Context.CacheDir.Path, this);
+			}
 		}
 
 		public void TriggerReload(Context ctx)
@@ -294,7 +301,32 @@ namespace keepass2android
             _db = new Database(new DrawableFactory(), this);
             return _db;
         }
-    }
+
+		void ShowToast(string message)
+		{
+			var handler = new Handler(Looper.MainLooper);
+			handler.Post(() => { Toast.MakeText(Application.Context, message, ToastLength.Long).Show(); });
+		}
+
+		public void CouldntSaveToRemote(IOConnectionInfo ioc, Exception e)
+		{
+			//TODO use resource strings
+			ShowToast("Couldn't save to remote: "+e.Message+". Save again or use Sync menu when remote connection is available again.");
+		}
+
+		//todo: test changes in SaveDb with Cache: Save without conflict, save with conflict
+		//add test?
+
+		public void CouldntOpenFromRemote(IOConnectionInfo ioc, Exception ex)
+		{
+			ShowToast("Couldn't open from remote: " + ex.Message+". Loaded file from local cache. You can still make changes in the database and sync them later.");
+		}
+
+		public void NotifyOpenFromLocalDueToConflict(IOConnectionInfo ioc)
+		{
+			ShowToast("Opened local file due to conflict with changes in remote file. Use Synchronize menu to merge.");
+		}
+	}
 
 
     ///Application class for Keepass2Android: Contains static Database variable to be used by all components.