XSD extension used to 1) resolve http://www.w3.org/2001/XMLSchema, 2)

cache XML Schema if no cache is set (see #178)

org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/xsd/XSDPlugin.java

@@ -0,0 +1,40 @@
+/**
+ *  Copyright (c) 2018 Angelo ZERR.
+ *  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
+ *
+ *  Contributors:
+ *  Angelo Zerr <angelo.zerr@gmail.com> - initial API and implementation
+ */
+package org.eclipse.lsp4xml.extensions.xsd;
+
+import org.eclipse.lsp4j.InitializeParams;
+import org.eclipse.lsp4xml.services.extensions.IXMLExtension;
+import org.eclipse.lsp4xml.services.extensions.XMLExtensionsRegistry;
+import org.eclipse.lsp4xml.uriresolver.URIResolverExtensionManager;
+
+/**
+ * XSD plugin.
+ */
+public class XSDPlugin implements IXMLExtension {
+
+	private XSDURIResolverExtension uiResolver;
+
+	@Override
+	public void updateSettings(Object settings) {
+
+	}
+
+	@Override
+	public void start(InitializeParams params, XMLExtensionsRegistry registry) {
+		uiResolver = new XSDURIResolverExtension(registry.getDocumentProvider());
+		URIResolverExtensionManager.getInstance().registerResolver(uiResolver);
+	}
+
+	@Override
+	public void stop(XMLExtensionsRegistry registry) {
+		URIResolverExtensionManager.getInstance().unregisterResolver(uiResolver);
+	}
+}

org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/xsd/XSDURIResolverExtension.java

@@ -0,0 +1,89 @@
+/**
+ *  Copyright (c) 2018 Angelo ZERR.
+ *  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
+ *
+ *  Contributors:
+ *  Angelo Zerr <angelo.zerr@gmail.com> - initial API and implementation
+ */
+package org.eclipse.lsp4xml.extensions.xsd;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+
+import org.apache.xerces.xni.XMLResourceIdentifier;
+import org.apache.xerces.xni.XNIException;
+import org.apache.xerces.xni.parser.XMLInputSource;
+import org.eclipse.lsp4xml.services.IXMLDocumentProvider;
+import org.eclipse.lsp4xml.uriresolver.CacheResourcesManager;
+import org.eclipse.lsp4xml.uriresolver.CacheResourcesManager.ResourceToDeploy;
+import org.eclipse.lsp4xml.uriresolver.URIResolverExtension;
+
+/**
+ * Resolve the XSD XML Schema and DTD dependencies.
+ *
+ */
+public class XSDURIResolverExtension implements URIResolverExtension {
+
+	/**
+	 * The XMLSchema namespace URI (= http://www.w3.org/2001/XMLSchema)
+	 */
+	private static final String SCHEMA_FOR_SCHEMA_URI_2001 = "http://www.w3.org/2001/XMLSchema"; //$NON-NLS-1$
+
+	private static final List<ResourceToDeploy> SCHEMA_URI_2001_RESOURCES = Arrays.asList(
+			new ResourceToDeploy("http://www.w3.org/2001/XMLSchema.xsd", "schemas/xsd/XMLSchema.xsd"),
+			new ResourceToDeploy("http://www.w3.org/2001/XMLSchema.dtd", "schemas/xsd/XMLSchema.dtd"),
+			new ResourceToDeploy("http://www.w3.org/2001/datatypes.dtd", "schemas/xsd/datatypes.dtd"));
+
+	/**
+	 * The Namespace namespace URI (= http://www.w3.org/XML/1998/namespace)
+	 */
+	private static final String SCHEMA_FOR_NAMESPACE_URI_1998 = "http://www.w3.org/XML/1998/namespace"; //$NON-NLS-1$
+
+	private static final ResourceToDeploy NAMESPACE_URI_1998_RESOURCE = new ResourceToDeploy(
+			"https://www.w3.org/2001/xml.xsd", "schemas/xsd/xml.xsd");
+
+	public XSDURIResolverExtension(IXMLDocumentProvider documentProvider) {
+
+	}
+
+	@Override
+	public String resolve(String baseLocation, String publicId, String systemId) {
+		if (SCHEMA_FOR_SCHEMA_URI_2001.equals(publicId)) {
+			try {
+				// Deploy XML Schema and DTDs on file systems.
+				for (ResourceToDeploy resource : SCHEMA_URI_2001_RESOURCES) {
+					CacheResourcesManager.getResourceCachePath(resource);
+				}
+				// Returns the patch of "http://www.w3.org/2001/XMLSchema.xsd" file system
+				return SCHEMA_URI_2001_RESOURCES.get(0).getDeployedPath().toFile().toURI().toString();
+			} catch (Exception e) {
+				// Do nothing?
+			}
+		} else if (SCHEMA_FOR_NAMESPACE_URI_1998.equals(publicId)) {
+			try {
+				return CacheResourcesManager.getResourceCachePath(NAMESPACE_URI_1998_RESOURCE).toFile().toURI()
+						.toString();
+			} catch (Exception e) {
+				// Do nothing?
+			}
+		}
+		return null;
+	}
+
+	@Override
+	public XMLInputSource resolveEntity(XMLResourceIdentifier resourceIdentifier) throws XNIException, IOException {
+		String publicId = resourceIdentifier.getNamespace();
+		if (SCHEMA_FOR_SCHEMA_URI_2001.equals(publicId) || SCHEMA_FOR_NAMESPACE_URI_1998.equals(publicId)) {
+			String baseLocation = resourceIdentifier.getBaseSystemId();
+			String xslFilePath = resolve(baseLocation, publicId, null);
+			if (xslFilePath != null) {
+				return new XMLInputSource(publicId, xslFilePath, xslFilePath);
+			}
+		}
+		return null;
+	}
+}

org.eclipse.lsp4xml/src/main/resources/META-INF/services/org.eclipse.lsp4xml.services.extensions.IXMLExtension

@@ -1,3 +1,4 @@
 org.eclipse.lsp4xml.extensions.contentmodel.ContentModelPlugin
 org.eclipse.lsp4xml.extensions.references.XMLReferencesPlugin
+org.eclipse.lsp4xml.extensions.xsd.XSDPlugin
 org.eclipse.lsp4xml.extensions.xsl.XSLPlugin