[lsi] Support of (cancellable) read/write requests

Change-Id: If294db6305bf836f0f7d75e47683e39730a975c0
Signed-off-by: akosyakov <anton.kosyakov@typefox.io>

plugins/org.eclipse.xtext.ide/META-INF/MANIFEST.MF

@@ -27,4 +27,8 @@ Export-Package: org.eclipse.xtext.ide;x-friends:="org.eclipse.xtend.ide",
  org.eclipse.xtext.ide.editor.partialEditing,
  org.eclipse.xtext.ide.editor.syntaxcoloring,
  org.eclipse.xtext.ide.labels;x-friends:="org.eclipse.xtext.web",
- org.eclipse.xtext.ide.server
+ org.eclipse.xtext.ide.server,
+ org.eclipse.xtext.ide.server.concurrent,
+ org.eclipse.xtext.ide.server.contentassist,
+ org.eclipse.xtext.ide.server.findReferences,
+ org.eclipse.xtext.ide.server.symbol

plugins/org.eclipse.xtext.ide/src/org/eclipse/xtext/ide/server/LanguageServerImpl.xtend

@@ -32,6 +32,7 @@ import io.typefox.lsapi.InitializeParams
 import io.typefox.lsapi.InitializeResult
 import io.typefox.lsapi.InitializeResultImpl
 import io.typefox.lsapi.LanguageServer
+import io.typefox.lsapi.Location
 import io.typefox.lsapi.MessageParams
 import io.typefox.lsapi.NotificationCallback
 import io.typefox.lsapi.PublishDiagnosticsParams
@@ -42,6 +43,7 @@ import io.typefox.lsapi.RenameParams
 import io.typefox.lsapi.ServerCapabilities
 import io.typefox.lsapi.ServerCapabilitiesImpl
 import io.typefox.lsapi.ShowMessageRequestParams
+import io.typefox.lsapi.SymbolInformation
 import io.typefox.lsapi.TextDocumentPositionParams
 import io.typefox.lsapi.TextDocumentService
 import io.typefox.lsapi.WindowService
@@ -51,6 +53,8 @@ import java.util.List
 import org.eclipse.emf.common.util.URI
 import org.eclipse.xtend.lib.annotations.Accessors
 import org.eclipse.xtext.ide.editor.contentassist.ContentAssistEntry
+import org.eclipse.xtext.ide.server.concurrent.CancellableIndicator
+import org.eclipse.xtext.ide.server.concurrent.RequestManager
 import org.eclipse.xtext.ide.server.contentassist.ContentAssistService
 import org.eclipse.xtext.ide.server.findReferences.WorkspaceResourceAccess
 import org.eclipse.xtext.ide.server.symbol.DocumentSymbolService
@@ -65,6 +69,9 @@ import static io.typefox.lsapi.util.LsapiFactories.*
  */
 @Accessors class LanguageServerImpl implements LanguageServer, WorkspaceService, WindowService, TextDocumentService {
 
+	@Inject
+	RequestManager requestManager
+
 	InitializeParams params
 	@Inject Provider<WorkspaceManager> workspaceManagerProvider
 	WorkspaceManager workspaceManager
@@ -72,26 +79,31 @@ import static io.typefox.lsapi.util.LsapiFactories.*
 	@Inject extension IResourceServiceProvider.Registry languagesRegistry
 
 	override InitializeResult initialize(InitializeParams params) {
+		if (params.rootPath === null) {
+			throw new IllegalArgumentException("Bad initialization request. rootPath must not be null.")
+		}
 		this.params = params
 		workspaceManager = workspaceManagerProvider.get
-		if (params.rootPath === null) {
-            throw new IllegalArgumentException("Bad initialization request. rootPath must not be null.")
-        }
-		val rootURI = URI.createFileURI(params.rootPath)
 		resourceAccess = new WorkspaceResourceAccess(workspaceManager)
-		workspaceManager.initialize(rootURI)[this.publishDiagnostics($0, $1)]
-		return new InitializeResultImpl => [
-			capabilities = new ServerCapabilitiesImpl => [
-				definitionProvider = true
-				referencesProvider = true
-				documentSymbolProvider = true
-				textDocumentSync = ServerCapabilities.SYNC_INCREMENTAL
-				completionProvider = new CompletionOptionsImpl => [
-					resolveProvider = false
-					triggerCharacters = #["."]
-				]
+
+		val result = new InitializeResultImpl
+		result.capabilities = new ServerCapabilitiesImpl => [
+			definitionProvider = true
+			referencesProvider = true
+			documentSymbolProvider = true
+			textDocumentSync = ServerCapabilities.SYNC_INCREMENTAL
+			completionProvider = new CompletionOptionsImpl => [
+				resolveProvider = false
+				triggerCharacters = #["."]
 			]
 		]
+
+		requestManager.runWrite([ cancelIndicator |
+			val rootURI = URI.createFileURI(params.rootPath)
+			workspaceManager.initialize(rootURI, [this.publishDiagnostics($0, $1)], cancelIndicator)
+		], CancellableIndicator.NullImpl)
+
+		return result
 	}
 
 	override exit() {
@@ -128,34 +140,44 @@ import static io.typefox.lsapi.util.LsapiFactories.*
 	// end notification callbacks
 	// file/content change events
 	override didOpen(DidOpenTextDocumentParams params) {
-		workspaceManager.didOpen(params.textDocument.uri.toUri, params.textDocument.version, params.textDocument.text)
+		requestManager.runWrite [ cancelIndicator |
+			workspaceManager.didOpen(params.textDocument.uri.toUri, params.textDocument.version, params.textDocument.text, cancelIndicator)
+		]
 	}
 
 	override didChange(DidChangeTextDocumentParams params) {
-		workspaceManager.didChange(params.textDocument.uri.toUri, params.textDocument.version, params.contentChanges.map [ event |
-			newTextEdit(event.range as RangeImpl, event.text)
-		])
+		requestManager.runWrite [ cancelIndicator |
+			workspaceManager.didChange(params.textDocument.uri.toUri, params.textDocument.version, params.contentChanges.map [ event |
+				newTextEdit(event.range as RangeImpl, event.text)
+			], cancelIndicator)
+		]
 	}
 
 	override didClose(DidCloseTextDocumentParams params) {
-		workspaceManager.didClose(params.textDocument.uri.toUri)
+		requestManager.runWrite [ cancelIndicator |
+			workspaceManager.didClose(params.textDocument.uri.toUri, cancelIndicator)
+		]
 	}
 
 	override didSave(DidSaveTextDocumentParams params) {
-		workspaceManager.didSave(params.textDocument.uri.toUri)
+		requestManager.runWrite [ cancelIndicator |
+			workspaceManager.didSave(params.textDocument.uri.toUri, cancelIndicator)
+		]
 	}
 
 	override didChangeWatchedFiles(DidChangeWatchedFilesParams params) {
-		val dirtyFiles = newArrayList
-		val deletedFiles = newArrayList
-		for (fileEvent : params.changes) {
-			if (fileEvent.type === FileEvent.TYPE_DELETED) {
-				deletedFiles += toUri(fileEvent.uri)
-			} else {
-				dirtyFiles += toUri(fileEvent.uri)
+		requestManager.runWrite [ cancelIndicator |
+			val dirtyFiles = newArrayList
+			val deletedFiles = newArrayList
+			for (fileEvent : params.changes) {
+				if (fileEvent.type === FileEvent.TYPE_DELETED) {
+					deletedFiles += toUri(fileEvent.uri)
+				} else {
+					dirtyFiles += toUri(fileEvent.uri)
+				}
 			}
-		}
-		workspaceManager.doBuild(dirtyFiles, deletedFiles)
+			workspaceManager.doBuild(dirtyFiles, deletedFiles, cancelIndicator)
+		]
 	}
 
 	// end file/content change events
@@ -198,17 +220,19 @@ import static io.typefox.lsapi.util.LsapiFactories.*
 	// end validation stuff
 	// completion stuff
 	override completion(TextDocumentPositionParams params) {
-		val uri = params.textDocument.uri.toUri
-		val resourceServiceProvider = uri.resourceServiceProvider
-		val contentAssistService = resourceServiceProvider?.get(ContentAssistService)
-		if (contentAssistService === null)
-			return emptyList
-
-		val entries = workspaceManager.doRead(uri) [ document, resource |
-			val offset = document.getOffSet(params.position)
-			return contentAssistService.createProposals(document.contents, offset, resource)
-		]
-		return entries.map[toCompletionItem].toList
+		return requestManager.runRead[ cancelIndicator |
+			val uri = params.textDocument.uri.toUri
+			val resourceServiceProvider = uri.resourceServiceProvider
+			val contentAssistService = resourceServiceProvider?.get(ContentAssistService)
+			if (contentAssistService === null)
+				return emptyList
+	
+			val entries = workspaceManager.doRead(uri) [ document, resource |
+				val offset = document.getOffSet(params.position)
+				return contentAssistService.createProposals(document.contents, offset, resource, cancelIndicator)
+			]
+			return entries.map[toCompletionItem].toList
+		].get
 	}
 
 	protected def CompletionItem toCompletionItem(ContentAssistEntry entry) {
@@ -222,50 +246,57 @@ import static io.typefox.lsapi.util.LsapiFactories.*
 	// end completion stuff
 	// symbols
 	override definition(TextDocumentPositionParams params) {
-		val uri = params.textDocument.uri.toUri
-		val resourceServiceProvider = uri.resourceServiceProvider
-		val documentSymbolService = resourceServiceProvider?.get(DocumentSymbolService)
-		if (documentSymbolService === null)
-			return emptyList
-
-		return workspaceManager.doRead(uri) [ document, resource |
-			val offset = document.getOffSet(params.position)
-			return documentSymbolService.getDefinitions(resource, offset, resourceAccess)
-		]
+		return requestManager.<List<? extends Location>>runRead[ cancelIndicator |
+			val uri = params.textDocument.uri.toUri
+			val resourceServiceProvider = uri.resourceServiceProvider
+			val documentSymbolService = resourceServiceProvider?.get(DocumentSymbolService)
+			if (documentSymbolService === null)
+				return emptyList
+	
+			val definitions = workspaceManager.doRead(uri) [ document, resource |
+				val offset = document.getOffSet(params.position)
+				return documentSymbolService.getDefinitions(resource, offset, resourceAccess, cancelIndicator)
+			]
+			return definitions
+		].get
 	}
 
 	override references(ReferenceParams params) {
-		val uri = params.textDocument.uri.toUri
-		val resourceServiceProvider = uri.resourceServiceProvider
-		val documentSymbolService = resourceServiceProvider?.get(DocumentSymbolService)
-		if (documentSymbolService === null)
-			return emptyList
-
-		return workspaceManager.doRead(uri) [ document, resource |
-			val offset = document.getOffSet(params.position)
-
-			val definitions = if (params.context.includeDeclaration)
-					documentSymbolService.getDefinitions(resource, offset, resourceAccess)
-				else
-					emptyList
-
-			val indexData = workspaceManager.index
-			val references = documentSymbolService.getReferences(resource, offset, resourceAccess, indexData)
-			val result = definitions + references
-			return result.toList
-		]
+		return requestManager.<List<? extends Location>>runRead[ cancelIndicator |
+			val uri = params.textDocument.uri.toUri
+			val resourceServiceProvider = uri.resourceServiceProvider
+			val documentSymbolService = resourceServiceProvider?.get(DocumentSymbolService)
+			if (documentSymbolService === null)
+				return emptyList
+	
+			return workspaceManager.doRead(uri) [ document, resource |
+				val offset = document.getOffSet(params.position)
+				
+				val definitions = if (params.context.includeDeclaration)
+						documentSymbolService.getDefinitions(resource, offset, resourceAccess, cancelIndicator)
+					else
+						emptyList
+				
+				val indexData = workspaceManager.index
+				val references = documentSymbolService.getReferences(resource, offset, resourceAccess, indexData, cancelIndicator)
+				val result = definitions + references
+				return result.toList
+			]
+		].get
 	}
 
 	override documentSymbol(DocumentSymbolParams params) {
-		val uri = params.textDocument.uri.toUri
-		val resourceServiceProvider = uri.resourceServiceProvider
-		val documentSymbolService = resourceServiceProvider?.get(DocumentSymbolService)
-		if (documentSymbolService === null)
-			return emptyList
-
-		return workspaceManager.doRead(uri) [ document, resource |
-			return documentSymbolService.getSymbols(resource)
-		]
+		return requestManager.<List<? extends SymbolInformation>>runRead[ cancelIndicator |
+			val uri = params.textDocument.uri.toUri
+			val resourceServiceProvider = uri.resourceServiceProvider
+			val documentSymbolService = resourceServiceProvider?.get(DocumentSymbolService)
+			if (documentSymbolService === null)
+				return emptyList
+	
+			return workspaceManager.doRead(uri) [ document, resource |
+				return documentSymbolService.getSymbols(resource, cancelIndicator)
+			]
+		].get
 	}
 
 	// end symbols

plugins/org.eclipse.xtext.ide/src/org/eclipse/xtext/ide/server/ProjectManager.xtend

@@ -27,6 +27,7 @@ import org.eclipse.xtext.resource.impl.ProjectDescription
 import org.eclipse.xtext.resource.impl.ResourceDescriptionsData
 import org.eclipse.xtext.util.IFileSystemScanner
 import org.eclipse.xtext.validation.Issue
+import org.eclipse.xtext.util.CancelIndicator
 
 /**
  * @author Sven Efftinge - Initial contribution and API
@@ -49,18 +50,18 @@ class ProjectManager {
     @Accessors(PUBLIC_GETTER)
     XtextResourceSet resourceSet
     
-    def Result initialize(URI baseDir, (URI, Iterable<Issue>)=>void acceptor, IExternalContentProvider openedDocumentsContentProvider, Provider<Map<String, ResourceDescriptionsData>> indexProvider) {
+    def Result initialize(URI baseDir, (URI, Iterable<Issue>)=>void acceptor, IExternalContentProvider openedDocumentsContentProvider, Provider<Map<String, ResourceDescriptionsData>> indexProvider, CancelIndicator cancelIndicator) {
         val uris = newArrayList
         this.baseDir = baseDir
         this.issueAcceptor = acceptor
         this.openedDocumentsContentProvider = openedDocumentsContentProvider
         this.indexProvider = indexProvider 
         this.fileSystemScanner.scan(baseDir)[uris += it]
-        return doBuild(uris, emptyList)
+        return doBuild(uris, emptyList, cancelIndicator)
     }
     
-    def Result doBuild(List<URI> dirtyFiles, List<URI> deletedFiles) {
-        val request = newBuildRequest(dirtyFiles, deletedFiles)
+    def Result doBuild(List<URI> dirtyFiles, List<URI> deletedFiles, CancelIndicator cancelIndicator) {
+        val request = newBuildRequest(dirtyFiles, deletedFiles, cancelIndicator)
         val result = incrementalBuilder.build(request, [
             languagesRegistry.getResourceServiceProvider(it)
         ])
@@ -69,7 +70,7 @@ class ProjectManager {
         return result;
     }
 
-    protected def BuildRequest newBuildRequest(List<URI> changedFiles, List<URI> deletedFiles) {
+    protected def BuildRequest newBuildRequest(List<URI> changedFiles, List<URI> deletedFiles, CancelIndicator cancelIndicator) {
         new BuildRequest => [
             it.baseDir = baseDir
             it.resourceSet = createFreshResourceSet(new ResourceDescriptionsData(emptyList))
@@ -81,6 +82,7 @@ class ProjectManager {
                 issueAcceptor.apply(uri, issues)
                 return true
             ]
+            it.cancelIndicator = cancelIndicator
         ]
     }
 

plugins/org.eclipse.xtext.ide/src/org/eclipse/xtext/ide/server/ServerModule.xtend

@@ -8,7 +8,11 @@
 package org.eclipse.xtext.ide.server
 
 import com.google.inject.AbstractModule
+import com.google.inject.name.Names
 import io.typefox.lsapi.LanguageServer
+import java.util.concurrent.ExecutorService
+import java.util.concurrent.Executors
+import org.eclipse.xtext.ide.server.concurrent.RequestManager
 import org.eclipse.xtext.resource.IResourceServiceProvider
 import org.eclipse.xtext.resource.ResourceServiceProviderServiceLoader
 
@@ -18,6 +22,12 @@ import org.eclipse.xtext.resource.ResourceServiceProviderServiceLoader
 class ServerModule extends AbstractModule {
     
     override protected configure() {
+		val readExecutorService = Executors.newCachedThreadPool
+		bind(ExecutorService).annotatedWith(Names.named(RequestManager.READ_EXECUTOR_SERVICE)).toInstance(readExecutorService)
+		
+		val writeExecutorService = Executors.newSingleThreadExecutor
+		bind(ExecutorService).annotatedWith(Names.named(RequestManager.WRITE_EXECUTOR_SERVICE)).toInstance(writeExecutorService)
+		
     	bind(LanguageServer).to(LanguageServerImpl)
         bind(IResourceServiceProvider.Registry).toProvider(ResourceServiceProviderServiceLoader)
     }

plugins/org.eclipse.xtext.ide/src/org/eclipse/xtext/ide/server/WorkspaceManager.xtend

@@ -11,15 +11,18 @@ import com.google.inject.Inject
 import com.google.inject.Provider
 import io.typefox.lsapi.TextEdit
 import java.util.ArrayList
+import java.util.Collection
 import java.util.List
 import java.util.Map
+import java.util.Set
 import org.eclipse.emf.common.util.URI
 import org.eclipse.xtext.resource.IExternalContentSupport.IExternalContentProvider
+import org.eclipse.xtext.resource.IResourceDescriptions
 import org.eclipse.xtext.resource.XtextResource
 import org.eclipse.xtext.resource.impl.ChunkedResourceDescriptions
 import org.eclipse.xtext.resource.impl.ResourceDescriptionsData
+import org.eclipse.xtext.util.CancelIndicator
 import org.eclipse.xtext.validation.Issue
-import org.eclipse.xtext.resource.IResourceDescriptions
 
 /**
  * @author Sven Efftinge - Initial contribution and API
@@ -46,25 +49,43 @@ class WorkspaceManager {
         }
     };
     Map<String, ResourceDescriptionsData> fullIndex = newHashMap()
+    
+    val dirtyFiles = <URI>newLinkedHashSet
+    val deletedFiles = <URI>newLinkedHashSet
+    
+    protected def void queue(Set<URI> files, Collection<URI> toRemove, Collection<URI> toAdd) {
+    	files -= toRemove
+    	files += toAdd
+    }
 
-    def void initialize(URI baseDir, (URI, Iterable<Issue>)=>void acceptor) {
+    def void initialize(URI baseDir, (URI, Iterable<Issue>)=>void acceptor, CancelIndicator cancelIndicator) {
         this.baseDir = baseDir
         // TODO support multi-projects
         // We will need to figure out how we can identify project structure, dependencies, source folders, etc...
         val projectManager = projectManagerProvider.get
-        val indexResult = projectManager.initialize(baseDir, acceptor, openedDocumentsContentProvider, [fullIndex])
+        val indexResult = projectManager.initialize(baseDir, acceptor, openedDocumentsContentProvider, [fullIndex], cancelIndicator)
         baseDir2ProjectManager.put(baseDir, projectManager)
         fullIndex.put("DEFAULT", indexResult.indexState.resourceDescriptions)
     }
 
-    def void doBuild(List<URI> dirtyFiles, List<URI> deletedFiles) {
-        //TODO sort projects by dependency
+    def void doBuild(List<URI> dirtyFiles, List<URI> deletedFiles, CancelIndicator cancelIndicator) {
+    	queue(this.dirtyFiles, deletedFiles, dirtyFiles)
+    	queue(this.deletedFiles, dirtyFiles, deletedFiles)
+    	internalBuild(cancelIndicator)
+    }
+    
+    protected def void internalBuild(CancelIndicator cancelIndicator) {
+    	//TODO sort projects by dependency
         val allDirty = new ArrayList(dirtyFiles)
         for (entry : baseDir2ProjectManager.entrySet) {
-            val projectDirtyFiles = allDirty.filter[isPrefix(entry.key)].toList
+        	val projectDirtyFiles = allDirty.filter[isPrefix(entry.key)].toList
 			val projectDeletedFiles = deletedFiles.filter[isPrefix(entry.key)].toList
-			val result = entry.value.doBuild(projectDirtyFiles, projectDeletedFiles)
-            allDirty.addAll(result.affectedResources.map[uri])
+			
+			val result = entry.value.doBuild(projectDirtyFiles, projectDeletedFiles, cancelIndicator)
+        	allDirty.addAll(result.affectedResources.map[uri])
+        	
+        	this.dirtyFiles -= projectDirtyFiles
+        	this.deletedFiles -= projectDeletedFiles
         }
     }
 
@@ -90,23 +111,23 @@ class WorkspaceManager {
         return baseDir2ProjectManager.get(projectBaseDir)
     }
 
-    def didChange(URI uri, int version, Iterable<TextEdit> changes) {
+    def didChange(URI uri, int version, Iterable<TextEdit> changes, CancelIndicator cancelIndicator) {
         val contents = openDocuments.get(uri)
         openDocuments.put(uri, contents.applyChanges(changes))
-        doBuild(#[uri], newArrayList)
+        doBuild(#[uri], newArrayList, cancelIndicator)
     }
     
-    def didOpen(URI uri, int version, String contents) {
+    def didOpen(URI uri, int version, String contents, CancelIndicator cancelIndicator) {
         openDocuments.put(uri, new Document(version, contents))
-        doBuild(#[uri], newArrayList)
+        doBuild(#[uri], newArrayList, cancelIndicator)
     }
     
-    def didClose(URI uri) {
+    def didClose(URI uri, CancelIndicator cancelIndicator) {
         openDocuments.remove(uri)
-        doBuild(#[uri], newArrayList)    
+        doBuild(#[uri], newArrayList, cancelIndicator)    
     }
     
-    def didSave(URI uri) {
+    def didSave(URI uri, CancelIndicator cancelIndicator) {
         // do nothing for now
     }
     

plugins/org.eclipse.xtext.ide/src/org/eclipse/xtext/ide/server/concurrent/CancellableIndicator.xtend

@@ -0,0 +1,17 @@
+/*******************************************************************************
+ * Copyright (c) 2016 TypeFox GmbH (http://www.typefox.io) and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *******************************************************************************/
+package org.eclipse.xtext.ide.server.concurrent
+
+import org.eclipse.xtext.util.CancelIndicator
+
+/**
+ * @author kosyakov - Initial contribution and API
+ */
+interface CancellableIndicator extends CancelIndicator {
+	def void cancel()
+}

plugins/org.eclipse.xtext.ide/src/org/eclipse/xtext/ide/server/concurrent/RequestCancelIndicator.xtend

@@ -0,0 +1,24 @@
+/*******************************************************************************
+ * Copyright (c) 2016 TypeFox GmbH (http://www.typefox.io) and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *******************************************************************************/
+package org.eclipse.xtext.ide.server.concurrent
+
+import org.eclipse.xtend.lib.annotations.Accessors
+
+/**
+ * @author kosyakov - Initial contribution and API
+ */
+class RequestCancelIndicator implements CancellableIndicator {
+	
+	@Accessors(PUBLIC_GETTER)
+	boolean canceled
+	
+	override cancel() {
+		canceled = true
+	}
+
+}

plugins/org.eclipse.xtext.ide/src/org/eclipse/xtext/ide/server/concurrent/RequestManager.xtend

@@ -0,0 +1,84 @@
+/*******************************************************************************
+ * Copyright (c) 2016 TypeFox GmbH (http://www.typefox.io) and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *******************************************************************************/
+package org.eclipse.xtext.ide.server.concurrent
+
+import com.google.inject.Inject
+import com.google.inject.Singleton
+import com.google.inject.name.Named
+import java.util.concurrent.ExecutorService
+import java.util.concurrent.Future
+import java.util.concurrent.LinkedBlockingQueue
+import java.util.concurrent.Semaphore
+import org.eclipse.xtext.util.CancelIndicator
+
+/**
+ * @author kosyakov - Initial contribution and API
+ */
+@Singleton
+class RequestManager {
+
+	public static val READ_EXECUTOR_SERVICE = 'org.eclipse.xtext.ide.server.concurrent.RequestManager.readExecutorService'
+	public static val WRITE_EXECUTOR_SERVICE = 'org.eclipse.xtext.ide.server.concurrent.RequestManager.writeExecutorService'
+
+	val final MAX_PERMITS = Integer.MAX_VALUE
+
+	@Inject
+	@Named(READ_EXECUTOR_SERVICE)
+	ExecutorService readExecutorService
+
+	@Inject
+	@Named(WRITE_EXECUTOR_SERVICE)
+	ExecutorService writeExecutorService
+
+	val cancelIndicators = new LinkedBlockingQueue<CancellableIndicator>
+
+	val semaphore = new Semaphore(MAX_PERMITS)
+
+	def Future<Void> runWrite((CancelIndicator)=>void writeRequest) {
+		runWrite(writeRequest, new RequestCancelIndicator)
+	}
+
+	def Future<Void> runWrite((CancelIndicator)=>void writeRequest, CancelIndicator cancelIndicator) {
+		cancelIndicators.forEach[cancel]
+		writeExecutorService.run([
+			writeRequest.apply(it)
+			return null
+		], MAX_PERMITS, cancelIndicator)
+	}
+
+	def <V> Future<V> runRead((CancelIndicator)=>V readRequest) {
+		runRead(readRequest, new RequestCancelIndicator)
+	}
+
+	def <V> Future<V> runRead((CancelIndicator)=>V readRequest, CancelIndicator cancelIndicator) {
+		readExecutorService.run(readRequest, 1, cancelIndicator)
+	}
+
+	protected def <V> Future<V> run(
+		ExecutorService executorService,
+		(CancelIndicator)=>V request,
+		int permits,
+		CancelIndicator cancelIndicator
+	) {
+		return executorService.submit [
+			semaphore.acquire(permits)
+			try {
+				if (cancelIndicator instanceof CancellableIndicator)
+					cancelIndicators += cancelIndicator
+
+				return request.apply(cancelIndicator)
+			} finally {
+				if (cancelIndicator instanceof CancellableIndicator)
+					cancelIndicators -= cancelIndicator
+
+				semaphore.release(permits)
+			}
+		]
+	}
+
+}

plugins/org.eclipse.xtext.ide/src/org/eclipse/xtext/ide/server/contentassist/ContentAssistService.xtend

@@ -18,6 +18,8 @@ import org.eclipse.xtext.ide.editor.contentassist.IdeContentProposalProvider
 import org.eclipse.xtext.ide.editor.contentassist.antlr.ContentAssistContextFactory
 import org.eclipse.xtext.resource.XtextResource
 import org.eclipse.xtext.util.TextRegion
+import org.eclipse.xtext.util.CancelIndicator
+import org.eclipse.xtext.service.OperationCanceledManager
 
 /**
  * @author kosyakov - Initial contribution and API
@@ -32,23 +34,17 @@ class ContentAssistService {
 	@Inject ExecutorService executorService
 
 	@Inject IdeContentProposalProvider proposalProvider
+	
+	@Inject OperationCanceledManager operationCanceledManager
 
 	def Iterable<ContentAssistEntry> createProposals(
 		String document,
 		int caretOffset,
-		XtextResource resource
+		XtextResource resource,
+		CancelIndicator cancelIndicator
 	) {
 		val selection = new TextRegion(caretOffset, 0)
-		return createProposals(document, selection, caretOffset, resource)
-	}
-
-	def Iterable<ContentAssistEntry> createProposals(
-		String document,
-		TextRegion selection,
-		int caretOffset,
-		XtextResource resource
-	) {
-		return createProposals(document, selection, caretOffset, resource, DEFAULT_PROPOSALS_LIMIT)
+		return createProposals(document, selection, caretOffset, resource, cancelIndicator)
 	}
 
 	def Iterable<ContentAssistEntry> createProposals(
@@ -56,7 +52,18 @@ class ContentAssistService {
 		TextRegion selection,
 		int caretOffset,
 		XtextResource resource,
-		int proposalsLimit
+		CancelIndicator cancelIndicator
+	) {
+		return createProposals(document, selection, caretOffset, resource, DEFAULT_PROPOSALS_LIMIT, cancelIndicator)
+	}
+
+	def Iterable<ContentAssistEntry> createProposals(
+		String document,
+		TextRegion selection,
+		int caretOffset,
+		XtextResource resource,
+		int proposalsLimit,
+		CancelIndicator cancelIndicator
 	) {
 		val entries = new TreeSet<Pair<Integer, ContentAssistEntry>> [ p1, p2 |
 			val prioResult = p2.key.compareTo(p1.key)
@@ -74,6 +81,7 @@ class ContentAssistService {
 						throw new IllegalArgumentException('proposal must not be null.')
 					entries.add(priority -> entry)
 				}
+				operationCanceledManager.checkCanceled(cancelIndicator)
 			}
 
 			override canAcceptMoreProposals() {

plugins/org.eclipse.xtext.ide/src/org/eclipse/xtext/ide/server/symbol/DocumentSymbolService.xtend

@@ -21,11 +21,14 @@ import org.eclipse.xtext.findReferences.ReferenceAcceptor
 import org.eclipse.xtext.findReferences.TargetURICollector
 import org.eclipse.xtext.findReferences.TargetURIs
 import org.eclipse.xtext.ide.server.DocumentExtensions
+import org.eclipse.xtext.ide.util.CancelIndicatorProgressMonitor
 import org.eclipse.xtext.naming.IQualifiedNameProvider
 import org.eclipse.xtext.resource.EObjectAtOffsetHelper
 import org.eclipse.xtext.resource.IResourceDescriptions
 import org.eclipse.xtext.resource.IResourceServiceProvider
 import org.eclipse.xtext.resource.XtextResource
+import org.eclipse.xtext.service.OperationCanceledManager
+import org.eclipse.xtext.util.CancelIndicator
 
 import static extension org.eclipse.emf.ecore.util.EcoreUtil.*
 
@@ -52,11 +55,19 @@ class DocumentSymbolService {
 
 	@Inject
 	Provider<TargetURIs> targetURIProvider
+	
+	@Inject
+	OperationCanceledManager operationCanceledManager
 
 	@Inject
 	IResourceServiceProvider.Registry resourceServiceProviderRegistry
 
-	def List<? extends Location> getDefinitions(XtextResource resource, int offset, IResourceAccess resourceAccess) {
+	def List<? extends Location> getDefinitions(
+		XtextResource resource,
+		int offset,
+		IResourceAccess resourceAccess,
+		CancelIndicator cancelIndicator
+	) {
 		val element = resource.resolveElementAt(offset)
 		if (element === null)
 			return emptyList
@@ -64,8 +75,13 @@ class DocumentSymbolService {
 		val locations = newArrayList
 		val targetURIs = element.collectTargetURIs
 		for (targetURI : targetURIs) {
+			operationCanceledManager.checkCanceled(cancelIndicator)
+
 			resourceAccess.readOnly(targetURI) [ resourceSet |
-				locations += resourceSet.getEObject(targetURI, true).newLocation
+				val object = resourceSet.getEObject(targetURI, true)
+				if (object !== null)
+					locations += object.newLocation
+				return null
 			]
 		}
 		return locations
@@ -75,7 +91,8 @@ class DocumentSymbolService {
 		XtextResource resource,
 		int offset,
 		IResourceAccess resourceAccess,
-		IResourceDescriptions indexData
+		IResourceDescriptions indexData,
+		CancelIndicator cancelIndicator
 	) {
 		val element = resource.resolveElementAt(offset)
 		if (element === null)
@@ -90,12 +107,13 @@ class DocumentSymbolService {
 			new ReferenceAcceptor(resourceServiceProviderRegistry) [ reference |
 				resourceAccess.readOnly(reference.sourceEObjectUri) [ resourceSet |
 					val targetObject = resourceSet.getEObject(reference.sourceEObjectUri, true)
-					locations += targetObject.newLocation(reference.EReference, reference.indexInList)
+					if (targetObject !== null)
+						locations += targetObject.newLocation(reference.EReference, reference.indexInList)
+					return null
 				]
 			],
-			null
+			new CancelIndicatorProgressMonitor(cancelIndicator)
 		)
-
 		return locations
 	}
 
@@ -105,10 +123,12 @@ class DocumentSymbolService {
 		return targetURIs
 	}
 
-	def List<? extends SymbolInformation> getSymbols(XtextResource resource) {
+	def List<? extends SymbolInformation> getSymbols(XtextResource resource, CancelIndicator cancelIndicator) {
 		val symbols = newLinkedHashMap
 		val contents = resource.getAllProperContents(true)
 		while (contents.hasNext) {
+			operationCanceledManager.checkCanceled(cancelIndicator)
+
 			val obj = contents.next
 			val symbol = obj.createSymbol
 			if (symbol !== null) {

plugins/org.eclipse.xtext.ide/src/org/eclipse/xtext/ide/util/CancelIndicatorProgressMonitor.xtend

@@ -0,0 +1,50 @@
+/*******************************************************************************
+ * Copyright (c) 2016 TypeFox GmbH (http://www.typefox.io) and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *******************************************************************************/
+package org.eclipse.xtext.ide.util
+
+import org.eclipse.core.runtime.IProgressMonitor
+import org.eclipse.xtend.lib.annotations.FinalFieldsConstructor
+import org.eclipse.xtext.util.CancelIndicator
+
+/**
+ * @author kosyakov - Initial contribution and API
+ */
+@FinalFieldsConstructor
+class CancelIndicatorProgressMonitor implements IProgressMonitor {
+
+	val CancelIndicator delegate	
+	
+	boolean canceled
+	
+	override isCanceled() {
+		canceled || delegate.isCanceled
+	}
+	
+	override setCanceled(boolean value) {
+		canceled = value
+	}
+	
+	override beginTask(String name, int totalWork) {
+	}
+	
+	override setTaskName(String name) {
+	}
+	
+	override subTask(String name) {
+	}
+	
+	override internalWorked(double work) {
+	}
+	
+	override worked(int work) {
+	}
+	
+	override done() {
+	}
+	
+}

tests/org.eclipse.xtext.ide.tests/src/org/eclipse/xtext/ide/tests/server/AbstractLanguageServerTest.xtend

@@ -7,6 +7,7 @@
  *******************************************************************************/
 package org.eclipse.xtext.ide.tests.server
 
+import com.google.inject.AbstractModule
 import com.google.inject.Guice
 import com.google.inject.Inject
 import io.typefox.lsapi.Diagnostic
@@ -28,13 +29,18 @@ import java.nio.file.Path
 import java.nio.file.Paths
 import java.util.List
 import java.util.Map
+import java.util.concurrent.ExecutorService
 import org.eclipse.xtext.ide.server.LanguageServerImpl
 import org.eclipse.xtext.ide.server.ServerModule
 import org.eclipse.xtext.ide.server.UriExtensions
+import org.eclipse.xtext.ide.server.concurrent.RequestManager
+import org.eclipse.xtext.util.CancelIndicator
 import org.eclipse.xtext.util.Files
+import org.eclipse.xtext.util.Modules2
 import org.junit.Before
 
 import static io.typefox.lsapi.util.LsapiFactories.*
+import com.google.common.util.concurrent.Futures
 
 /**
  * @author Sven Efftinge - Initial contribution and API
@@ -43,7 +49,20 @@ class AbstractLanguageServerTest implements NotificationCallback<PublishDiagnost
 
 	@Before
 	def void setup() {
-		val injector = Guice.createInjector(new ServerModule())
+		val module = Modules2.mixin(new ServerModule, new AbstractModule() {
+			
+			override protected configure() {
+				bind(RequestManager).toInstance(new RequestManager() {
+					
+					override protected <V> run(ExecutorService executorService, (CancelIndicator)=>V request, int permits, CancelIndicator cancelIndicator) {
+						Futures.immediateCheckedFuture(request.apply(cancelIndicator))
+					}
+					
+				})
+			}
+			
+		})
+		val injector = Guice.createInjector(module)
 		injector.injectMembers(this)
 		// register notification callbacks
 		languageServer.getTextDocumentService.onPublishDiagnostics(this)

tests/org.eclipse.xtext.ide.tests/src/org/eclipse/xtext/ide/tests/server/WorkspaceManagerTest.xtend

@@ -34,7 +34,7 @@ class WorkspaceManagerTest {
             }
         '''
         
-        workspaceManger.doBuild(#[path], emptyList)
+        workspaceManger.doBuild(#[path], emptyList, null)
         
         val String inMemContents = '''
             type Test {
@@ -42,7 +42,7 @@ class WorkspaceManagerTest {
             }
         '''
         
-        workspaceManger.didOpen(path, 1, inMemContents)
+        workspaceManger.didOpen(path, 1, inMemContents, null)
         
         Assert.assertEquals(inMemContents, workspaceManger.doRead(path, [$0.contents]))
     }
@@ -60,7 +60,7 @@ class WorkspaceManagerTest {
             Files.cleanFolder(root, null, true, false)
         }
         root.deleteOnExit
-        workspaceManger.initialize(URI.createFileURI(root.absolutePath), [diagnostics.put($0, $1.toList)])
+        workspaceManger.initialize(URI.createFileURI(root.absolutePath), [diagnostics.put($0, $1.toList)], null)
     }
 
     protected Map<URI, List<Issue>> diagnostics = newHashMap()