Bug 510898 - (Dirty) support for code actions

Change-Id: Icd27d8e78f04305e1a9131d8902a5bb0ba2874b4
Signed-off-by: Mickael Istria <mistria@redhat.com>

11 files changed, 140 insertions, 47 deletions

diff --git a/org.eclipse.lsp4e.languages/src/org/eclipse/lsp4e/languages/CSSLanguageServer.java b/org.eclipse.lsp4e.languages/src/org/eclipse/lsp4e/languages/CSSLanguageServer.java
index 4ba9df17..df4a49c0 100644
--- a/org.eclipse.lsp4e.languages/src/org/eclipse/lsp4e/languages/CSSLanguageServer.java
+++ b/org.eclipse.lsp4e.languages/src/org/eclipse/lsp4e/languages/CSSLanguageServer.java
@@ -10,6 +10,7 @@
  *******************************************************************************/
 package org.eclipse.lsp4e.languages;
 
+import java.net.URI;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -41,7 +42,7 @@ public class CSSLanguageServer extends ProcessStreamConnectionProvider {
 	}
 	
 	@Override
-	public Object getInitializationOptions(String rootPath) {
+	public Object getInitializationOptions(URI rootUri) {
 		Map<String, Object> settings = new HashMap<>();
 		settings.put("css", Collections.singletonMap("validate", true));
 		settings.put("scss", Collections.singletonMap("validate", true));
@@ -49,12 +50,13 @@ public class CSSLanguageServer extends ProcessStreamConnectionProvider {
 		return settings;
 	}
 	
-	public void handleMessage(Message message, LanguageServer languageServer, String rootPath) {
+	@Override
+	public void handleMessage(Message message, LanguageServer languageServer, URI rootUri) {
 		if (message instanceof ResponseMessage) {
 			ResponseMessage responseMessage = (ResponseMessage)message;
 			if (responseMessage.getResult() instanceof InitializeResult) {
 				// enable validation: so far, no better way found than changing conf after init.
-				DidChangeConfigurationParams params = new DidChangeConfigurationParams(getInitializationOptions(rootPath));
+				DidChangeConfigurationParams params = new DidChangeConfigurationParams(getInitializationOptions(rootUri));
 				languageServer.getWorkspaceService().didChangeConfiguration(params);
 			}
 		}
diff --git a/org.eclipse.lsp4e.languages/src/org/eclipse/lsp4e/languages/HTMLLanguageServer.java b/org.eclipse.lsp4e.languages/src/org/eclipse/lsp4e/languages/HTMLLanguageServer.java
index 3d20a5b0..18043439 100644
--- a/org.eclipse.lsp4e.languages/src/org/eclipse/lsp4e/languages/HTMLLanguageServer.java
+++ b/org.eclipse.lsp4e.languages/src/org/eclipse/lsp4e/languages/HTMLLanguageServer.java
@@ -10,6 +10,7 @@
  *******************************************************************************/
 package org.eclipse.lsp4e.languages;
 
+import java.net.URI;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -30,7 +31,7 @@ public class HTMLLanguageServer extends ProcessStreamConnectionProvider {
 	}
 
 	@Override
-	public Object getInitializationOptions(String rootPath) {
+	public Object getInitializationOptions(URI rootUri) {
 		Map<String, Object> map = new HashMap<>();
 		map.put("css", true);
 		map.put("javascript", true);
diff --git a/org.eclipse.lsp4e.test/src/org/eclipse/lsp4e/test/hover/HoverTest.java b/org.eclipse.lsp4e.test/src/org/eclipse/lsp4e/test/hover/HoverTest.java
index 9d3a9aa3..6e649c0c 100644
--- a/org.eclipse.lsp4e.test/src/org/eclipse/lsp4e/test/hover/HoverTest.java
+++ b/org.eclipse.lsp4e.test/src/org/eclipse/lsp4e/test/hover/HoverTest.java
@@ -51,7 +51,7 @@ public class HoverTest {
 
 	@Test
 	public void testHoverRegion() throws CoreException, InvocationTargetException {
-		Hover hoverResponse = new Hover(Either.forLeft(Either.forLeft("HoverContent")), new Range(new Position(0,  0), new Position(0, 10)));
+		Hover hoverResponse = new Hover(Collections.singletonList(Either.forLeft("HoverContent")), new Range(new Position(0,  0), new Position(0, 10)));
 		MockLanguageSever.INSTANCE.setHover(hoverResponse);
 
 		IFile file = TestUtils.createUniqueTestFile(project, "HoverRange Other Text");
@@ -72,7 +72,7 @@ public class HoverTest {
 	
 	@Test
 	public void testHoverInfo() throws CoreException, InvocationTargetException {
-		Hover hoverResponse = new Hover(Either.forLeft(Either.forLeft("HoverContent")), new Range(new Position(0,  0), new Position(0, 10)));
+		Hover hoverResponse = new Hover(Collections.singletonList(Either.forLeft("HoverContent")), new Range(new Position(0,  0), new Position(0, 10)));
 		MockLanguageSever.INSTANCE.setHover(hoverResponse);
 
 		IFile file = TestUtils.createUniqueTestFile(project, "HoverRange Other Text");
@@ -84,7 +84,7 @@ public class HoverTest {
 	
 	@Test
 	public void testHoverInfoEmptyContentList() throws CoreException, InvocationTargetException {
-		Hover hoverResponse = new Hover(Either.forRight(Collections.emptyList()), new Range(new Position(0,  0), new Position(0, 10)));
+		Hover hoverResponse = new Hover(Collections.emptyList(), new Range(new Position(0,  0), new Position(0, 10)));
 		MockLanguageSever.INSTANCE.setHover(hoverResponse);
 
 		IFile file = TestUtils.createUniqueTestFile(project, "HoverRange Other Text");
diff --git a/org.eclipse.lsp4e.tests.mock/src/org/eclipse/lsp4e/tests/mock/MockTextDocumentService.java b/org.eclipse.lsp4e.tests.mock/src/org/eclipse/lsp4e/tests/mock/MockTextDocumentService.java
index 0e3b2bf7..557777ec 100644
--- a/org.eclipse.lsp4e.tests.mock/src/org/eclipse/lsp4e/tests/mock/MockTextDocumentService.java
+++ b/org.eclipse.lsp4e.tests.mock/src/org/eclipse/lsp4e/tests/mock/MockTextDocumentService.java
@@ -62,7 +62,7 @@ public class MockTextDocumentService implements TextDocumentService {
 		CompletionItem item = new CompletionItem();
 		item.setLabel("Mock completion item");
 		mockCompletionList = new CompletionList(false, Collections.singletonList(item));
-		mockHover = new Hover(Either.forLeft(Either.forLeft("Mock hover")), null);
+		mockHover = new Hover(Collections.singletonList(Either.forLeft("Mock hover")), null);
 	}
 
 	private <U> CompletableFuture<U> futureFactory(U value) {
@@ -92,8 +92,8 @@ public class MockTextDocumentService implements TextDocumentService {
 	}
 
 	@Override
-	public CompletableFuture<Either<Location, List<? extends Location>>> definition(TextDocumentPositionParams position) {
-		return CompletableFuture.completedFuture(Either.forRight(mockDefinitionLocations));
+	public CompletableFuture<List<? extends Location>> definition(TextDocumentPositionParams position) {
+		return CompletableFuture.completedFuture(mockDefinitionLocations);
 	}
 
 	@Override
diff --git a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/LSPEclipseUtils.java b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/LSPEclipseUtils.java
index b1ff9e61..968a655e 100644
--- a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/LSPEclipseUtils.java
+++ b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/LSPEclipseUtils.java
@@ -39,6 +39,7 @@ import org.eclipse.lsp4j.Position;
 import org.eclipse.lsp4j.TextDocumentIdentifier;
 import org.eclipse.lsp4j.TextDocumentPositionParams;
 import org.eclipse.lsp4j.TextEdit;
+import org.eclipse.lsp4j.WorkspaceEdit;
 import org.eclipse.text.edits.MalformedTreeException;
 import org.eclipse.text.edits.MultiTextEdit;
 import org.eclipse.text.edits.ReplaceEdit;
@@ -108,7 +109,7 @@ public class LSPEclipseUtils {
 			return project.findMember(projectRelativePath);
 		}
 	}
-	
+
 	public static void applyEdit(TextEdit textEdit, IDocument document) throws BadLocationException {
 		document.replace(
 				LSPEclipseUtils.toOffset(textEdit.getRange().getStart(), document),
@@ -119,7 +120,7 @@ public class LSPEclipseUtils {
 	/**
 	 * Method will apply all edits to document as single modification. Needs to
 	 * be executed in UI thread.
-	 * 
+	 *
 	 * @param document
 	 *            document to modify
 	 * @param edits
@@ -230,4 +231,12 @@ public class LSPEclipseUtils {
 		}
 	}
 
+	public static void applyWorkspaceEdit(WorkspaceEdit wsEdit) {
+		for (java.util.Map.Entry<String, List<TextEdit>> edit : wsEdit.getChanges().entrySet()) {
+			String uri = edit.getKey();
+			IDocument document = LSPEclipseUtils.getDocument(LSPEclipseUtils.findResourceFor(uri));
+			LSPEclipseUtils.applyEdits(document, edit.getValue());
+		}
+	}
+
 }
diff --git a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/ProjectSpecificLanguageServerWrapper.java b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/ProjectSpecificLanguageServerWrapper.java
index 800f6ad6..0f7036da 100644
--- a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/ProjectSpecificLanguageServerWrapper.java
+++ b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/ProjectSpecificLanguageServerWrapper.java
@@ -11,6 +11,7 @@
 package org.eclipse.lsp4e;
 
 import java.io.IOException;
+import java.net.URI;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -42,7 +43,10 @@ import org.eclipse.jface.text.IDocument;
 import org.eclipse.lsp4e.operations.diagnostics.LSPDiagnosticsToMarkers;
 import org.eclipse.lsp4e.server.StreamConnectionProvider;
 import org.eclipse.lsp4e.ui.Messages;
+import org.eclipse.lsp4j.ApplyWorkspaceEditParams;
+import org.eclipse.lsp4j.ApplyWorkspaceEditResponse;
 import org.eclipse.lsp4j.ClientCapabilities;
+import org.eclipse.lsp4j.ExecuteCommandCapabilites;
 import org.eclipse.lsp4j.InitializeParams;
 import org.eclipse.lsp4j.InitializeResult;
 import org.eclipse.lsp4j.MessageActionItem;
@@ -50,8 +54,10 @@ import org.eclipse.lsp4j.MessageParams;
 import org.eclipse.lsp4j.PublishDiagnosticsParams;
 import org.eclipse.lsp4j.ServerCapabilities;
 import org.eclipse.lsp4j.ShowMessageRequestParams;
+import org.eclipse.lsp4j.SymbolCapabilites;
 import org.eclipse.lsp4j.TextDocumentSyncKind;
 import org.eclipse.lsp4j.TextDocumentSyncOptions;
+import org.eclipse.lsp4j.WorkspaceClientCapabilites;
 import org.eclipse.lsp4j.jsonrpc.Launcher;
 import org.eclipse.lsp4j.jsonrpc.ResponseErrorException;
 import org.eclipse.lsp4j.jsonrpc.messages.Either;
@@ -166,16 +172,24 @@ public class ProjectSpecificLanguageServerWrapper {
 				public void logMessage(MessageParams message) {
 					ServerMessageHandler.logMessage(project, label, message);
 				}
+
+				@Override
+				public CompletableFuture<ApplyWorkspaceEditResponse> applyEdit(ApplyWorkspaceEditParams params) {
+					return CompletableFuture.supplyAsync(() -> {
+						LSPEclipseUtils.applyWorkspaceEdit(params.getEdit());
+						return new ApplyWorkspaceEditResponse(true);
+					});
+				}
 			};
 			ExecutorService executorService = Executors.newCachedThreadPool();
 			final InitializeParams initParams = new InitializeParams();
-			initParams.setRootPath(project.getLocation().toFile().getAbsolutePath());
+			initParams.setRootUri(project.getLocation().toFile().toURI().toString());
 			Launcher<LanguageServer> launcher = LSPLauncher.createClientLauncher(client,
 					this.lspStreamProvider.getInputStream(), this.lspStreamProvider.getOutputStream(), executorService,
 					consumer -> (message -> {
 						consumer.consume(message);
 						logMessage(message);
-						this.lspStreamProvider.handleMessage(message, this.languageServer, initParams.getRootPath());
+						this.lspStreamProvider.handleMessage(message, this.languageServer, URI.create(initParams.getRootUri()));
 					}));
 			this.languageServer = launcher.getRemoteProxy();
 			this.launcherFuture = launcher.startListening();
@@ -184,10 +198,15 @@ public class ProjectSpecificLanguageServerWrapper {
 			if (Platform.getProduct() != null) {
 				name = Platform.getProduct().getName();
 			}
+			WorkspaceClientCapabilites workspaceClientCapabilites = new WorkspaceClientCapabilites();
+			workspaceClientCapabilites.setApplyEdit(Boolean.TRUE);
+			workspaceClientCapabilites.setExecuteCommand(new ExecuteCommandCapabilites());
+			workspaceClientCapabilites.setSymbol(new SymbolCapabilites());
+			initParams.setCapabilities(new ClientCapabilities(workspaceClientCapabilites, null, null));
 			initParams.setClientName(name);
 			initParams.setCapabilities(new ClientCapabilities());
 			initParams.setInitializationOptions(
-					this.lspStreamProvider.getInitializationOptions(initParams.getRootPath()));
+					this.lspStreamProvider.getInitializationOptions(URI.create(initParams.getRootUri())));
 			initializeFuture = languageServer.initialize(initParams).thenApply(res -> {
 				initializeResult = res;
 				return res;
diff --git a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/codeactions/CodeActionMarkerResolution.java b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/codeactions/CodeActionMarkerResolution.java
index 9ca6d091..b8b7421e 100644
--- a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/codeactions/CodeActionMarkerResolution.java
+++ b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/codeactions/CodeActionMarkerResolution.java
@@ -10,19 +10,31 @@
  *******************************************************************************/
 package org.eclipse.lsp4e.operations.codeactions;
 
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
 import org.eclipse.core.resources.IMarker;
-import org.eclipse.jface.dialogs.MessageDialog;
+import org.eclipse.core.resources.IResource;
+import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.lsp4e.LSPEclipseUtils;
+import org.eclipse.lsp4e.LanguageServerPlugin;
 import org.eclipse.lsp4j.Command;
+import org.eclipse.lsp4j.TextEdit;
+import org.eclipse.lsp4j.WorkspaceEdit;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.ui.IMarkerResolution;
-import org.eclipse.ui.PlatformUI;
 import org.eclipse.ui.views.markers.WorkbenchMarkerResolution;
 
+import com.google.gson.Gson;
+
 public class CodeActionMarkerResolution extends WorkbenchMarkerResolution implements IMarkerResolution {
 
-	private Command command;
+	private @NonNull Command command;
 
-	public CodeActionMarkerResolution(Command command) {
+	public CodeActionMarkerResolution(@NonNull Command command) {
 		this.command = command;
 	}
 
@@ -33,17 +45,73 @@ public class CodeActionMarkerResolution extends WorkbenchMarkerResolution implem
 
 	@Override
 	public void run(IMarker marker) {
-		MessageDialog.openWarning(PlatformUI.getWorkbench().getActiveWorkbenchWindow().getShell(), "Not yet supported", "LSP Commands are not yet supported");  //$NON-NLS-1$//$NON-NLS-2$
+		try {
+			// This is a *client-side* command, no need to go through workspace/executeCommand operation
+			// TODO? Consider binding LS commands to Eclipse commands and handlers???
+			if (command.getArguments() != null) {
+				WorkspaceEdit edit = createWorkspaceEdit(command.getArguments(), marker.getResource());
+				LSPEclipseUtils.applyWorkspaceEdit(edit);
+			}
+		} catch (Exception e) {
+			LanguageServerPlugin.logError(e);
+		}
+	}
+
+	private static final class Pair<K, V> {
+		K key;
+		V value;
+		Pair(K key,V value) {
+			this.key = key;
+			this.value = value;
+		}
+	}
+
+	/**
+	 * Very empirical and unsafe heuristic to turn unknown command arguments
+	 * into a workspace edit...
+	 */
+	private WorkspaceEdit createWorkspaceEdit(List<Object> arguments, IResource initialResource) {
+		WorkspaceEdit res = new WorkspaceEdit();
+		Map<String, List<TextEdit>> changes = new HashMap<>();
+		res.setChanges(changes);
+		Pair<IResource, List<TextEdit>> currentEntry = new Pair<>(initialResource, new ArrayList<>());
+		arguments.stream().flatMap(item -> {
+			if (item instanceof List) {
+				return ((List<?>)item).stream();
+			} else {
+				return Collections.singleton(item).stream();
+			}
+		}).forEach(arg -> {
+			if (arg instanceof String) {
+				changes.put(currentEntry.key.getLocationURI().toString(), currentEntry.value);
+				IResource resource = LSPEclipseUtils.findResourceFor((String)arg);
+				if (resource != null) {
+					currentEntry.key = resource;
+					currentEntry.value = new ArrayList<>();
+				}
+			} else if (arg instanceof WorkspaceEdit) {
+				changes.putAll(((WorkspaceEdit)arg).getChanges());
+			} else if (arg instanceof TextEdit) {
+				currentEntry.value.add((TextEdit)arg);
+			} else if (arg instanceof Map) {
+				Gson gson = new Gson(); // TODO? retrieve the GSon used by LS
+				TextEdit edit = gson.fromJson(gson.toJson(arg), TextEdit.class);
+				if (edit != null) {
+					currentEntry.value.add(edit);
+				}
+			}
+		});
+		changes.put(currentEntry.key.getLocationURI().toString(), currentEntry.value);
+		return res;
 	}
 
 	@Override
 	public String getDescription() {
-		return null;
+		return command.getTitle();
 	}
 
 	@Override
 	public Image getImage() {
-		// TODO Auto-generated method stub
 		return null;
 	}
 
diff --git a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/codeactions/LSPCodeActionMarkerResolution.java b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/codeactions/LSPCodeActionMarkerResolution.java
index 8334d5e7..a647d95b 100644
--- a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/codeactions/LSPCodeActionMarkerResolution.java
+++ b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/codeactions/LSPCodeActionMarkerResolution.java
@@ -15,6 +15,7 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.TimeUnit;
 
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IMarker;
@@ -40,6 +41,7 @@ import org.eclipse.ui.internal.progress.ProgressInfoItem;
 public class LSPCodeActionMarkerResolution implements IMarkerResolutionGenerator2 {
 
 	private static final String LSP_REMEDIATION = "lspCodeActions"; //$NON-NLS-1$
+	private static final String LS = "languageServer"; //$NON-NLS-1$
 
 	private static final IMarkerResolution2 COMPUTING = new IMarkerResolution2() {
 
@@ -47,6 +49,7 @@ public class LSPCodeActionMarkerResolution implements IMarkerResolutionGenerator
 		public void run(IMarker marker) {
 			// TODO Auto-generated method stub
 			// join on Future?
+
 		}
 
 		@Override
@@ -71,9 +74,11 @@ public class LSPCodeActionMarkerResolution implements IMarkerResolutionGenerator
 	@Override
 	public IMarkerResolution[] getResolutions(IMarker marker) {
 		Object att;
+		LanguageServer languageServer = null;
 		try {
 			checkMarkerResoultion(marker);
 			att = marker.getAttribute(LSP_REMEDIATION);
+			languageServer = (LanguageServer) marker.getAttribute(LS);
 		} catch (Exception e) {
 			LanguageServerPlugin.logError(e);
 			return new IMarkerResolution[0];
@@ -84,7 +89,9 @@ public class LSPCodeActionMarkerResolution implements IMarkerResolutionGenerator
 		List<? extends Command> commands = (List<? extends Command>)att;
 		List<IMarkerResolution> res = new ArrayList<>(commands.size());
 		for (Command command : commands) {
-			res.add(new CodeActionMarkerResolution(command));
+			if (command != null) {
+				res.add(new CodeActionMarkerResolution(command));
+			}
 		}
 		return res.toArray(new IMarkerResolution[res.size()]);
 	}
@@ -96,6 +103,7 @@ public class LSPCodeActionMarkerResolution implements IMarkerResolutionGenerator
 			LanguageServer lsp = LanguageServiceAccessor.getLanguageServer((IFile)marker.getResource(), (capabilities) -> Boolean.TRUE.equals(capabilities.getCodeActionProvider()));
 			if (lsp != null) {
 				marker.setAttribute(LSP_REMEDIATION, COMPUTING);
+				marker.setAttribute(LS, lsp);
 				Diagnostic diagnostic = (Diagnostic)marker.getAttribute(LSPDiagnosticsToMarkers.LSP_DIAGNOSTIC);
 				CodeActionContext context = new CodeActionContext(Collections.singletonList(diagnostic));
 				CodeActionParams params = new CodeActionParams();
@@ -110,6 +118,8 @@ public class LSPCodeActionMarkerResolution implements IMarkerResolutionGenerator
 						LanguageServerPlugin.logError(e);
 					}
 				});
+				// wait a bit to avoid showing too much "Computing" without looking like a freeze
+				codeAction.get(300, TimeUnit.MILLISECONDS);
 			}
 		}
 	}
diff --git a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/declaration/OpenDeclarationHyperlinkDetector.java b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/declaration/OpenDeclarationHyperlinkDetector.java
index 563b4687..19ca4734 100644
--- a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/declaration/OpenDeclarationHyperlinkDetector.java
+++ b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/declaration/OpenDeclarationHyperlinkDetector.java
@@ -12,7 +12,6 @@
 package org.eclipse.lsp4e.operations.declaration;
 
 import java.util.ArrayList;
-import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
@@ -32,7 +31,6 @@ import org.eclipse.lsp4e.LanguageServiceAccessor;
 import org.eclipse.lsp4e.LanguageServiceAccessor.LSPDocumentInfo;
 import org.eclipse.lsp4e.ui.Messages;
 import org.eclipse.lsp4j.Location;
-import org.eclipse.lsp4j.jsonrpc.messages.Either;
 import org.eclipse.ui.IWorkbenchPage;
 import org.eclipse.ui.PlatformUI;
 
@@ -76,19 +74,10 @@ public class OpenDeclarationHyperlinkDetector extends AbstractHyperlinkDetector
 		final LSPDocumentInfo info = LanguageServiceAccessor.getLSPDocumentInfoFor(textViewer, (capabilities) -> Boolean.TRUE.equals(capabilities.getDefinitionProvider()));
 		if (info != null) {
 			try {
-				CompletableFuture<Either<Location, List<? extends Location>>> documentHighlight = info.getLanguageClient().getTextDocumentService()
+				CompletableFuture<List<? extends Location>> documentHighlight = info.getLanguageClient().getTextDocumentService()
 						.definition(LSPEclipseUtils.toTextDocumentPosistionParams(info.getFileUri(), region.getOffset(), info.getDocument()));
-				Either<Location, List<? extends Location>> response = documentHighlight.get(2, TimeUnit.SECONDS);
-				if (response == null) {
-					return null;
-				}
-				List<? extends Location> locations = Collections.emptyList();
-				if (response.isLeft()) {
-					locations = Collections.singletonList(response.getLeft());
-				} else if (response.isRight()) {
-					locations = response.getRight();
-				}
-				if (locations.isEmpty()) {
+				List<? extends Location> locations = documentHighlight.get(2, TimeUnit.SECONDS);
+				if (locations == null || locations.isEmpty()) {
 					return null;
 				}
 				IRegion linkRegion = findWord(textViewer.getDocument(), region.getOffset());
diff --git a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/hover/LSBasedHover.java b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/hover/LSBasedHover.java
index d57be3ec..5d4e2049 100644
--- a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/hover/LSBasedHover.java
+++ b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/operations/hover/LSBasedHover.java
@@ -10,7 +10,6 @@
  *******************************************************************************/
 package org.eclipse.lsp4e.operations.hover;
 
-import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutionException;
@@ -96,12 +95,7 @@ public class LSBasedHover implements ITextHover, ITextHoverExtension {
 		if (hoverResult == null) {
 			return null;
 		}
-		List<Either<String, MarkedString>> contents = null;
-		if (hoverResult.getContents().isLeft()) {
-			contents = Collections.singletonList(hoverResult.getContents().getLeft());
-		} else if (hoverResult.getContents().isRight()) {
-			contents = hoverResult.getContents().getRight();
-		}
+		List<Either<String, MarkedString>> contents = hoverResult.getContents();
 		if (contents == null || contents.isEmpty()) {
 			return null;
 		}
diff --git a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/server/StreamConnectionProvider.java b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/server/StreamConnectionProvider.java
index 8b70b4a7..7390db10 100644
--- a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/server/StreamConnectionProvider.java
+++ b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/server/StreamConnectionProvider.java
@@ -13,6 +13,7 @@ package org.eclipse.lsp4e.server;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.net.URI;
 
 import org.eclipse.lsp4j.jsonrpc.messages.Message;
 import org.eclipse.lsp4j.services.LanguageServer;
@@ -43,7 +44,7 @@ public interface StreamConnectionProvider {
 	/**
      * User provided initialization options.
      */
-	public default Object getInitializationOptions(String rootPath){
+	public default Object getInitializationOptions(URI rootUri){
 		return null;
 	}
 
@@ -53,8 +54,8 @@ public interface StreamConnectionProvider {
 	 * Allows to hook custom behavior on messages.
 	 * @param message a message
 	 * @param languageServer the language server receiving/sending the message.
-	 * @param rootPath
+	 * @param rootUri
 	 */
-	public default void handleMessage(Message message, LanguageServer languageServer, String rootPath) {}
+	public default void handleMessage(Message message, LanguageServer languageServer, URI rootURI) {}
 
 }