Refactored Vault, MPCs, Unlock to integrate better with latest changes

Removed delegate to Volume#getMountPointRequirement() from Vault
Added getter for the Vault's Volume (#getVolume())

Changed CustomMountPointChooser to use VaultSettings instead of Vault for the constructor/field declaration
Updated CustomMountPointChooser#isApplicable() to be disabled when using FUSE on Windows (without useExperimentalFuse)
Updated CustomMountPointChooser to call Volume#getMountPointRequirement() directly

Replaced OS-Check in TemporaryMountPointChooser with MPR-Check

Replaced call to Vault#getMountPointRequirement() with call to Vault#getVolume() (and Volume#getMountPointRequirement()) in UnlockInvalidMountPointController and UnlockWorkflow
Cleaned up UnlockWorkflow

main/commons/src/main/java/org/cryptomator/common/mountpoint/CustomMountPointChooser.java

@@ -1,6 +1,9 @@
 package org.cryptomator.common.mountpoint;
 
-import org.cryptomator.common.vaults.Vault;
+import org.apache.commons.lang3.SystemUtils;
+import org.cryptomator.common.Environment;
+import org.cryptomator.common.settings.VaultSettings;
+import org.cryptomator.common.settings.VolumeImpl;
 import org.cryptomator.common.vaults.Volume;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -23,27 +26,30 @@ public class CustomMountPointChooser implements MountPointChooser {
 
 	private static final Logger LOG = LoggerFactory.getLogger(CustomMountPointChooser.class);
 
-	private final Vault vault;
+	private final VaultSettings vaultSettings;
+	private final Environment environment;
 
 	@Inject
-	public CustomMountPointChooser(Vault vault) {
-		this.vault = vault;
+	public CustomMountPointChooser(VaultSettings vaultSettings, Environment environment) {
+		this.vaultSettings = vaultSettings;
+		this.environment = environment;
 	}
 
 	@Override
 	public boolean isApplicable(Volume caller) {
-		return true;
+		//Disable if useExperimentalFuse is required (Win + Fuse), but set to false
+		return caller.getImplementationType() != VolumeImpl.FUSE || !SystemUtils.IS_OS_WINDOWS || environment.useExperimentalFuse();
 	}
 
 	@Override
 	public Optional<Path> chooseMountPoint(Volume caller) {
 		//VaultSettings#getCustomMountPath already checks whether the saved custom mountpoint should be used
-		return this.vault.getVaultSettings().getCustomMountPath().map(Paths::get);
+		return this.vaultSettings.getCustomMountPath().map(Paths::get);
 	}
 
 	@Override
 	public boolean prepare(Volume caller, Path mountPoint) throws InvalidMountPointException {
-		switch (this.vault.getMountPointRequirement()) {
+		switch (caller.getMountPointRequirement()) {
 			case PARENT_NO_MOUNT_POINT -> prepareParentNoMountPoint(mountPoint);
 			case EMPTY_MOUNT_POINT -> prepareEmptyMountPoint(mountPoint);
 			case NONE -> {

main/commons/src/main/java/org/cryptomator/common/mountpoint/TemporaryMountPointChooser.java

@@ -67,16 +67,26 @@ public class TemporaryMountPointChooser implements MountPointChooser {
 		}
 
 		try {
-			//WinFSP needs the parent, but the actual Mountpoint must not exist...
-			if (SystemUtils.IS_OS_WINDOWS) {
-				Files.createDirectories(mountPoint.getParent());
-				LOG.debug("Successfully created folder for mount point: {}", mountPoint);
-				return false;
-			} else {
-				//For Linux and Mac the actual Mountpoint must exist
-				Files.createDirectories(mountPoint);
-				LOG.debug("Successfully created mount point: {}", mountPoint);
-				return true;
+			switch (caller.getMountPointRequirement()) {
+				case PARENT_NO_MOUNT_POINT -> {
+					Files.createDirectories(mountPoint.getParent());
+					LOG.debug("Successfully created folder for mount point: {}", mountPoint);
+					return false;
+				}
+				case EMPTY_MOUNT_POINT -> {
+					Files.createDirectories(mountPoint);
+					LOG.debug("Successfully created mount point: {}", mountPoint);
+					return true;
+				}
+				case NONE -> {
+					//Requirement "NONE" doesn't make any sense here.
+					//No need to prepare/verify a Mountpoint without requiring one...
+					throw new InvalidMountPointException(new IllegalStateException("Illegal MountPointRequirement"));
+				}
+				default -> {
+					//Currently the case for "PARENT_OPT_MOUNT_POINT"
+					throw new InvalidMountPointException(new IllegalStateException("Not implemented"));
+				}
 			}
 		} catch (IOException exception) {
 			throw new InvalidMountPointException("IOException while preparing mountpoint", exception);

main/commons/src/main/java/org/cryptomator/common/vaults/Vault.java

@@ -39,6 +39,7 @@ import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.EnumSet;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicReference;
 
@@ -316,8 +317,8 @@ public class Vault {
 		return vaultSettings.getId();
 	}
 
-	public MountPointRequirement getMountPointRequirement() {
-		return volume.getMountPointRequirement();
+	public Optional<Volume> getVolume() {
+		return Optional.ofNullable(this.volume);
 	}
 
 	// ******************************************************************************

main/ui/src/main/java/org/cryptomator/ui/unlock/UnlockInvalidMountPointController.java

@@ -38,7 +38,7 @@ public class UnlockInvalidMountPointController implements FxController {
 	}
 
 	public boolean getMustExist() {
-		MountPointRequirement requirement = vault.getMountPointRequirement();
+		MountPointRequirement requirement = vault.getVolume().orElseThrow(() -> new IllegalStateException("Invalid Mountpoint without a Volume?!")).getMountPointRequirement();
 		assert requirement != MountPointRequirement.NONE; //An invalid MountPoint with no required MountPoint doesn't seem sensible
 		assert requirement != MountPointRequirement.PARENT_OPT_MOUNT_POINT; //Not implemented anywhere (yet)
 

main/ui/src/main/java/org/cryptomator/ui/unlock/UnlockWorkflow.java

@@ -157,7 +157,7 @@ public class UnlockWorkflow extends Task<Boolean> {
 	}
 
 	private void handleInvalidMountPoint(InvalidMountPointException impExc) {
-		MountPointRequirement requirement = vault.getMountPointRequirement();
+		MountPointRequirement requirement = vault.getVolume().orElseThrow(() -> new IllegalStateException("Invalid Mountpoint without a Volume?!", impExc)).getMountPointRequirement();
 		assert requirement != MountPointRequirement.NONE; //An invalid MountPoint with no required MountPoint doesn't seem sensible
 		assert requirement != MountPointRequirement.PARENT_OPT_MOUNT_POINT; //Not implemented anywhere (yet)
 
@@ -165,14 +165,14 @@ public class UnlockWorkflow extends Task<Boolean> {
 		//Cause is either null (cause the IMPE was thrown directly, e.g. because no MPC succeeded)
 		//or the cause was not an Exception (but some other kind of Throwable)
 		//Either way: Handle as generic error
-		if(!(cause instanceof Exception)) {
+		if (!(cause instanceof Exception)) {
 			handleGenericError(impExc);
 			return;
 		}
 
 		//From here on handle the cause, not the caught exception
-		if(cause instanceof NotDirectoryException) {
-			if(requirement == MountPointRequirement.PARENT_NO_MOUNT_POINT) {
+		if (cause instanceof NotDirectoryException) {
+			if (requirement == MountPointRequirement.PARENT_NO_MOUNT_POINT) {
 				LOG.error("Unlock failed. Parent folder is missing: {}", cause.getMessage());
 			} else {
 				LOG.error("Unlock failed. Mountpoint doesn't exist (needs to be a folder): {}", cause.getMessage());
@@ -181,13 +181,13 @@ public class UnlockWorkflow extends Task<Boolean> {
 			return;
 		}
 
-		if(cause instanceof FileAlreadyExistsException) {
+		if (cause instanceof FileAlreadyExistsException) {
 			LOG.error("Unlock failed. Mountpoint already exists: {}", cause.getMessage());
 			showInvalidMountPointScene();
 			return;
 		}
 
-		if(cause instanceof DirectoryNotEmptyException) {
+		if (cause instanceof DirectoryNotEmptyException) {
 			LOG.error("Unlock failed. Mountpoint not an empty directory: {}", cause.getMessage());
 			showInvalidMountPointScene();
 			return;