Bug 558664 - Cquery integration should be extracted from LSP Core

Part 6:
Declare SupportedProtocolExtensions interface to access contributed
LanguageProtocolExtension for a given language server.
Extract ResolvePreferredServer class.
Add ContributedProtocolExtensions OSGi component with tests.

Change-Id: Iecb1fff5a29a559e3c9d8703cc7d8fa71bb18042
Signed-off-by: Alexander Fedorov <alexander.fedorov@arsysop.ru>

lsp/org.eclipse.cdt.lsp.core.tests/src/org/eclipse/cdt/lsp/internal/core/tests/ContributedProtocolExtensionsTest.java

@@ -0,0 +1,55 @@
+/*******************************************************************************
+ * Copyright (c) 2020 ArSysOp and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Alexander Fedorov (ArSysOp) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.lsp.internal.core.tests;
+
+import static org.junit.Assert.assertEquals;
+
+import org.eclipse.cdt.lsp.LanguageProtocolExtension;
+import org.eclipse.cdt.lsp.LanguageServerConfiguration;
+import org.eclipse.cdt.lsp.internal.core.ContributedProtocolExtensions;
+import org.junit.Test;
+
+public class ContributedProtocolExtensionsTest {
+
+	private final LanguageServerConfiguration s1 = new FakeServerConfiguration("s1");
+	private final LanguageServerConfiguration s2 = new FakeServerConfiguration("s2");
+	private final LanguageServerConfiguration s3 = new FakeServerConfiguration("s3");
+	private final LanguageProtocolExtension p1s1 = new FakeProtocolExtension("s1");
+	private final LanguageProtocolExtension p2s1 = new FakeProtocolExtension("s1");
+	private final LanguageProtocolExtension p3s2 = new FakeProtocolExtension("s2");
+
+	@Test
+	public void positive() {
+		ContributedProtocolExtensions extensions = new ContributedProtocolExtensions();
+		assertEquals(0, extensions.all().size());
+		assertEquals(0, extensions.applicable(s1).size());
+		assertEquals(0, extensions.applicable(s2).size());
+		assertEquals(0, extensions.applicable(s3).size());
+		extensions.register(p1s1);
+		extensions.register(p2s1);
+		extensions.register(p3s2);
+		assertEquals(3, extensions.all().size());
+		assertEquals(2, extensions.applicable(s1).size());
+		assertEquals(1, extensions.applicable(s2).size());
+		assertEquals(0, extensions.applicable(s3).size());
+		extensions.unregister(p1s1);
+		extensions.unregister(p2s1);
+		extensions.unregister(p3s2);
+		assertEquals(0, extensions.all().size());
+		assertEquals(0, extensions.applicable(s1).size());
+		assertEquals(0, extensions.applicable(s2).size());
+		assertEquals(0, extensions.applicable(s3).size());
+	}
+
+}

lsp/org.eclipse.cdt.lsp.core.tests/src/org/eclipse/cdt/lsp/internal/core/tests/FakeProtocolExtension.java

@@ -0,0 +1,31 @@
+/*******************************************************************************
+ * Copyright (c) 2020 ArSysOp and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Alexander Fedorov (ArSysOp) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.lsp.internal.core.tests;
+
+import org.eclipse.cdt.lsp.LanguageProtocolExtension;
+
+public class FakeProtocolExtension implements LanguageProtocolExtension {
+
+	private final String id;
+
+	public FakeProtocolExtension(String id) {
+		this.id = id;
+	}
+
+	@Override
+	public String targetIdentifier() {
+		return id;
+	}
+
+}

lsp/org.eclipse.cdt.lsp.core.tests/src/org/eclipse/cdt/lsp/internal/core/tests/FakeServerConfiguration.java

@@ -0,0 +1,43 @@
+/*******************************************************************************
+ * Copyright (c) 2020 ArSysOp and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Alexander Fedorov (ArSysOp) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.lsp.internal.core.tests;
+
+import java.net.URI;
+
+import org.eclipse.cdt.lsp.LanguageServerConfiguration;
+
+public class FakeServerConfiguration implements LanguageServerConfiguration {
+
+	private final String id;
+
+	public FakeServerConfiguration(String id) {
+		this.id = id;
+	}
+
+	@Override
+	public String identifier() {
+		return id;
+	}
+
+	@Override
+	public String label() {
+		return id;
+	}
+
+	@Override
+	public Object options(Object defaults, URI uri) {
+		return defaults;
+	}
+
+}

lsp/org.eclipse.cdt.lsp.core.tests/src/org/eclipse/cdt/lsp/internal/core/tests/ShowStatusTest.java

@@ -11,7 +11,7 @@
  * Contributors:
  *     Alexander Fedorov (ArSysOp) - initial API and implementation
  *******************************************************************************/
-package org.eclipse.cdt.lsp.core.tests;
+package org.eclipse.cdt.lsp.internal.core.tests;
 
 import static org.junit.Assert.assertEquals;
 

lsp/org.eclipse.cdt.lsp.core/META-INF/MANIFEST.MF

@@ -35,4 +35,5 @@ Bundle-Activator: org.eclipse.cdt.lsp.core.Activator
 Bundle-ActivationPolicy: lazy
 Service-Component: OSGI-INF/org.eclipse.cdt.lsp.internal.core.ContributedLanguageServers.xml,
  OSGI-INF/org.eclipse.cdt.internal.clangd.ClangdLanguageServer.xml,
- OSGI-INF/org.eclipse.cdt.internal.cquery.CqueryLanguageServer.xml
+ OSGI-INF/org.eclipse.cdt.internal.cquery.CqueryLanguageServer.xml,
+ OSGI-INF/org.eclipse.cdt.lsp.internal.core.ContributedProtocolExtensions.xml

lsp/org.eclipse.cdt.lsp.core/OSGI-INF/org.eclipse.cdt.lsp.internal.core.ContributedProtocolExtensions.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<scr:component xmlns:scr="http://www.osgi.org/xmlns/scr/v1.1.0" name="org.eclipse.cdt.lsp.internal.core.ContributedProtocolExtensions">
+   <service>
+      <provide interface="org.eclipse.cdt.lsp.SupportedProtocolExtensions"/>
+   </service>
+   <reference bind="register" cardinality="0..n" interface="org.eclipse.cdt.lsp.LanguageProtocolExtension" name="register" unbind="unregister"/>
+   <implementation class="org.eclipse.cdt.lsp.internal.core.ContributedProtocolExtensions"/>
+</scr:component>

lsp/org.eclipse.cdt.lsp.core/src/org/eclipse/cdt/lsp/LanguageProtocolExtension.java

@@ -0,0 +1,34 @@
+/*******************************************************************************
+ * Copyright (c) 2020 ArSysOp and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Alexander Fedorov (ArSysOp) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.lsp;
+
+import org.eclipse.lsp4j.jsonrpc.services.ServiceEndpoints;
+
+/**
+ *
+ * Declares the language protocol extension methods.
+ *
+ * @see ServiceEndpoints#getSupportedMethods(Class)
+ *
+ */
+public interface LanguageProtocolExtension {
+
+	/**
+	 *
+	 * @return the identifier of the target language server
+	 * @see LanguageServerConfiguration#identifier()
+	 */
+	String targetIdentifier();
+
+}

lsp/org.eclipse.cdt.lsp.core/src/org/eclipse/cdt/lsp/SupportedLanguageServers.java

@@ -17,7 +17,7 @@ import java.util.Collection;
 
 /**
  *
- * Provides access to configurations of supported language servers.
+ * Provides access to the configurations of supported language servers.
  *
  */
 public interface SupportedLanguageServers {

lsp/org.eclipse.cdt.lsp.core/src/org/eclipse/cdt/lsp/SupportedProtocolExtensions.java

@@ -0,0 +1,29 @@
+/*******************************************************************************
+ * Copyright (c) 2020 ArSysOp and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Alexander Fedorov (ArSysOp) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.lsp;
+
+import java.util.Collection;
+
+/**
+ *
+ * Provides access to the language protocol extensions.
+ *
+ */
+public interface SupportedProtocolExtensions {
+
+	Collection<LanguageProtocolExtension> all();
+
+	Collection<LanguageProtocolExtension> applicable(LanguageServerConfiguration server);
+
+}

lsp/org.eclipse.cdt.lsp.core/src/org/eclipse/cdt/lsp/core/CPPStreamConnectionProvider.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2017-2020 Ericsson and others.
+ * Copyright (c) 2017, 2020 Ericsson and others.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License 2.0 which is available at
@@ -25,14 +25,13 @@ import java.util.Arrays;
 import java.util.List;
 
 import org.eclipse.cdt.lsp.LanguageServerConfiguration;
-import org.eclipse.cdt.lsp.SupportedLanguageServers;
+import org.eclipse.cdt.lsp.internal.core.ResolvePreferredServer;
 import org.eclipse.cdt.utils.CommandLineUtil;
 import org.eclipse.core.resources.IContainer;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.resources.IResourceChangeListener;
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.Platform;
-import org.eclipse.core.runtime.ServiceCaller;
 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.lsp4e.server.ProcessStreamConnectionProvider;
 
@@ -47,7 +46,7 @@ public class CPPStreamConnectionProvider extends ProcessStreamConnectionProvider
 	private final LanguageServerConfiguration configuration;
 
 	public CPPStreamConnectionProvider() throws UnsupportedOperationException {
-		configuration = configuration();
+		configuration = new ResolvePreferredServer().apply(getClass());
 		File defaultLSLocation = getDefaultLSLocation(configuration.identifier());
 		if (defaultLSLocation != null) {
 			store.setDefault(PreferenceConstants.P_SERVER_PATH, defaultLSLocation.getAbsolutePath());
@@ -67,13 +66,6 @@ public class CPPStreamConnectionProvider extends ProcessStreamConnectionProvider
 		setCommands(commands);
 	}
 
-	private LanguageServerConfiguration configuration() {
-		final LanguageServerConfiguration[] configs = new LanguageServerConfiguration[1];
-		ServiceCaller.callOnce(CPPStreamConnectionProvider.class, SupportedLanguageServers.class,
-				x -> configs[0] = x.preferred());
-		return configs[0];
-	}
-
 	@Override
 	public void stop() {
 		super.stop();

lsp/org.eclipse.cdt.lsp.core/src/org/eclipse/cdt/lsp/internal/core/ContributedProtocolExtensions.java

@@ -0,0 +1,74 @@
+/*******************************************************************************
+ * Copyright (c) 2020 ArSysOp and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Alexander Fedorov (ArSysOp) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.lsp.internal.core;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+import org.eclipse.cdt.lsp.LanguageProtocolExtension;
+import org.eclipse.cdt.lsp.LanguageServerConfiguration;
+import org.eclipse.cdt.lsp.SupportedProtocolExtensions;
+import org.osgi.service.component.annotations.Component;
+import org.osgi.service.component.annotations.Reference;
+import org.osgi.service.component.annotations.ReferenceCardinality;
+
+@Component
+public final class ContributedProtocolExtensions implements SupportedProtocolExtensions {
+
+	private final Map<String, List<LanguageProtocolExtension>> extensions;
+
+	public ContributedProtocolExtensions() {
+		extensions = new LinkedHashMap<>();
+	}
+
+	@Override
+	public Collection<LanguageProtocolExtension> all() {
+		return extensions.values().stream()//
+				.flatMap(List::stream)//
+				.collect(Collectors.toList());
+	}
+
+	@Override
+	public Collection<LanguageProtocolExtension> applicable(LanguageServerConfiguration server) {
+		return new ArrayList<>(extensions.getOrDefault(server.identifier(), Collections.emptyList()));
+	}
+
+	@Reference(cardinality = ReferenceCardinality.MULTIPLE)
+	public void register(LanguageProtocolExtension extension) {
+		List<LanguageProtocolExtension> list = extensions.computeIfAbsent(extension.targetIdentifier(),
+				x -> new ArrayList<>());
+		if (!list.contains(extension)) {
+			list.add(extension);
+		}
+	}
+
+	public void unregister(LanguageProtocolExtension extension) {
+		Optional<List<LanguageProtocolExtension>> optional = Optional
+				.ofNullable(extensions.get(extension.targetIdentifier()));
+		if (optional.isPresent()) {
+			List<LanguageProtocolExtension> list = optional.get();
+			list.remove(extension);
+			if (list.isEmpty()) {
+				extensions.remove(extension.targetIdentifier());
+			}
+		}
+	}
+
+}

lsp/org.eclipse.cdt.lsp.core/src/org/eclipse/cdt/lsp/internal/core/ResolvePreferredServer.java

@@ -0,0 +1,31 @@
+/*******************************************************************************
+ * Copyright (c) 2020 ArSysOp and others.
+ *
+ * This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License 2.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *     Alexander Fedorov (ArSysOp) - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.cdt.lsp.internal.core;
+
+import java.util.function.Function;
+
+import org.eclipse.cdt.lsp.LanguageServerConfiguration;
+import org.eclipse.cdt.lsp.SupportedLanguageServers;
+import org.eclipse.core.runtime.ServiceCaller;
+
+public final class ResolvePreferredServer implements Function<Class<?>, LanguageServerConfiguration> {
+
+	@Override
+	public LanguageServerConfiguration apply(Class<?> caller) {
+		LanguageServerConfiguration[] configs = new LanguageServerConfiguration[1];
+		ServiceCaller.callOnce(caller, SupportedLanguageServers.class, x -> configs[0] = x.preferred());
+		return configs[0];
+	}
+
+}