Grammar generator from XML

Fixes eclipse-lemminx#778

Signed-off-by: azerr <azerr@redhat.com>

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/extensions/generators/AbstractXML2GrammarGenerator.java

@@ -0,0 +1,132 @@
+/*******************************************************************************
+* Copyright (c) 2020 Red Hat Inc. and others.
+* All rights reserved. This program and the accompanying materials
+* which accompanies this distribution, and is available at
+* http://www.eclipse.org/legal/epl-v20.html
+*
+* SPDX-License-Identifier: EPL-2.0
+*
+* Contributors:
+*     Red Hat Inc. - initial API and implementation
+*******************************************************************************/
+package org.eclipse.lemminx.extensions.generators;
+
+import org.eclipse.lemminx.commons.TextDocument;
+import org.eclipse.lemminx.dom.DOMAttr;
+import org.eclipse.lemminx.services.IXMLFullFormatter;
+import org.eclipse.lemminx.settings.SharedSettings;
+import org.eclipse.lemminx.utils.XMLBuilder;
+import org.w3c.dom.Attr;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.w3c.dom.NamedNodeMap;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+
+/**
+ * Abstract class to generate a grammar (XSD, DTD, etcc) from a given XML
+ * source.
+ * 
+ * <p>
+ * The process is to build a generic {@link Grammar} instance from the XML
+ * source and each implementation uses this grammar information to generate the
+ * proper grammar.
+ * </p>
+ * 
+ * @param <T> the grammar generator settings.
+ */
+public abstract class AbstractXML2GrammarGenerator<T extends FileContentGeneratorSettings>
+		implements IFileContentGenerator<Document, T> {
+
+	@Override
+	public String generate(Document document, SharedSettings sharedSettings, T generatorSettings,
+			IXMLFullFormatter formatter) {
+		String newText = doGenerate(document, sharedSettings, generatorSettings);
+		if (formatter == null) {
+			return newText;
+		}
+		return formatter.formatFull(new TextDocument(newText, "grammar." + getFileExtension()), sharedSettings);
+	}
+
+	protected abstract String getFileExtension();
+
+	private String doGenerate(Document document, SharedSettings sharedSettings, T generatorSettings) {
+		// Create the generic grammar information from the XML source document.
+		Grammar grammar = createGrammar(document, isFlat());
+		XMLBuilder builder = new XMLBuilder(sharedSettings, "", "");
+		// Generate the grammar content from the grammar information.
+		generate(grammar, generatorSettings, builder);
+		return builder.toString();
+	}
+
+	protected boolean isFlat() {
+		return false;
+	}
+
+	/**
+	 * Generate the grammar content from the given grammr information into the given
+	 * builder.
+	 * 
+	 * @param grammar         the grammar information.
+	 * @param grammarSettings the grammar settings
+	 * @param out             the XML builder to update.
+	 */
+	protected abstract void generate(Grammar grammar, T grammarSettings, XMLBuilder out);
+
+	private Grammar createGrammar(Document document, boolean flat) {
+		Grammar grammar = new Grammar();
+		// Update default namespace
+		String defaultNamespace = null;
+		Element documentElement = document.getDocumentElement();
+		if (documentElement != null) {
+			defaultNamespace = document.getDocumentElement().getAttribute(DOMAttr.XMLNS_ATTR);
+		}
+		grammar.setDefaultNamespace(defaultNamespace);
+		// Update elements information
+		fillElements(document, grammar, grammar, flat);
+		return grammar;
+	}
+
+	private static void fillElements(Node node, Grammar grammar, ChildrenDeclaration container, boolean flat) {
+		NodeList children = node.getChildNodes();
+		for (int i = 0; i < children.getLength(); i++) {
+			Node child = children.item(i);
+			if (child.getNodeType() == Node.ELEMENT_NODE) {
+				Element element = (Element) child;
+				ElementDeclaration elementDecl = null;
+				if (flat) {
+					elementDecl = grammar.getElement(element.getLocalName());
+					container.addElement(elementDecl);
+				} else {
+					elementDecl = container.getElement(element.getLocalName());
+				}
+				// Update count occurrences
+				elementDecl.incrementOccurrences();
+				// Update has text
+				if (!elementDecl.hasCharacterContent()) {
+					elementDecl.setHasCharacterContent(hasCharacterContent(element));
+				}
+				// Update attributes
+				NamedNodeMap attributes = element.getAttributes();
+				if (attributes != null) {
+					for (int j = 0; j < attributes.getLength(); j++) {
+						Attr attr = (Attr) attributes.item(i);
+						elementDecl.getAttribute(attr.getName());
+					}
+				}
+				fillElements(element, grammar, elementDecl, flat);
+			}
+		}
+	}
+
+	private static boolean hasCharacterContent(Element element) {
+		NodeList children = element.getChildNodes();
+		for (int i = 0; i < children.getLength(); i++) {
+			Node child = children.item(i);
+			if (child.getNodeType() == Node.TEXT_NODE) {
+				return true;
+			}
+		}
+		return false;
+	}
+}

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/extensions/generators/AttributeDeclaration.java

@@ -0,0 +1,34 @@
+/*******************************************************************************
+* Copyright (c) 2020 Red Hat Inc. and others.
+* All rights reserved. This program and the accompanying materials
+* which accompanies this distribution, and is available at
+* http://www.eclipse.org/legal/epl-v20.html
+*
+* SPDX-License-Identifier: EPL-2.0
+*
+* Contributors:
+*     Red Hat Inc. - initial API and implementation
+*******************************************************************************/
+package org.eclipse.lemminx.extensions.generators;
+
+/**
+ * Attribute declaration.
+ *
+ */
+public class AttributeDeclaration {
+
+	private final String name;
+
+	public AttributeDeclaration(String name) {
+		this.name = name;
+	}
+
+	/**
+	 * Returns the attribute name.
+	 * 
+	 * @return the attribute name.
+	 */
+	public String getName() {
+		return name;
+	}
+}

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/extensions/generators/ChildrenDeclaration.java

@@ -0,0 +1,65 @@
+/*******************************************************************************
+* Copyright (c) 2020 Red Hat Inc. and others.
+* All rights reserved. This program and the accompanying materials
+* which accompanies this distribution, and is available at
+* http://www.eclipse.org/legal/epl-v20.html
+*
+* SPDX-License-Identifier: EPL-2.0
+*
+* Contributors:
+*     Red Hat Inc. - initial API and implementation
+*******************************************************************************/
+package org.eclipse.lemminx.extensions.generators;
+
+import java.util.Collection;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+/**
+ * Children information.
+ *
+ */
+public class ChildrenDeclaration {
+
+	private final Map<String, ElementDeclaration> children;
+
+	public ChildrenDeclaration() {
+		this.children = new LinkedHashMap<>();
+	}
+
+	/**
+	 * Returns the element information for the given name and create it if not
+	 * found.
+	 * 
+	 * @param name the element name
+	 * @return the element information for the given name and create it if not
+	 *         found.
+	 */
+	public ElementDeclaration getElement(String name) {
+		ElementDeclaration element = children.get(name);
+		if (element != null) {
+			return element;
+		}
+		element = createElement(name);
+		addElement(element);
+		return element;
+	}
+
+	protected ElementDeclaration createElement(String name) {
+		return new ElementDeclaration(name, null);
+	}
+
+	public void addElement(ElementDeclaration element) {
+		children.put(element.getName(), element);
+	}
+
+	/**
+	 * Returns the elements information of the node.
+	 * 
+	 * @return the elements information of the node.
+	 */
+	public Collection<ElementDeclaration> getElements() {
+		return children.values();
+	}
+
+}

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/extensions/generators/ElementDeclaration.java

@@ -0,0 +1,101 @@
+/*******************************************************************************
+* Copyright (c) 2020 Red Hat Inc. and others.
+* All rights reserved. This program and the accompanying materials
+* which accompanies this distribution, and is available at
+* http://www.eclipse.org/legal/epl-v20.html
+*
+* SPDX-License-Identifier: EPL-2.0
+*
+* Contributors:
+*     Red Hat Inc. - initial API and implementation
+*******************************************************************************/
+package org.eclipse.lemminx.extensions.generators;
+
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * Element information.
+ *
+ */
+public class ElementDeclaration extends ChildrenDeclaration {
+
+	private final String name;
+
+	private final ElementDeclaration parent;
+
+	private final Map<String, AttributeDeclaration> attributes;
+
+	private boolean hasCharacterContent;
+
+	private int occurrences;
+
+	public ElementDeclaration(String name, ElementDeclaration parent) {
+		this.name = name;
+		this.parent = parent;
+		this.attributes = new HashMap<>();
+		this.occurrences = 0;
+	}
+
+	/**
+	 * Returns the element name.
+	 * 
+	 * @return the element name.
+	 */
+	public String getName() {
+		return name;
+	}
+
+	/**
+	 * Returns the attribute information for the given name and create it if not
+	 * found.
+	 * 
+	 * @param name the attribute name
+	 * @return the attribute information for the given name and create it if not
+	 *         found.
+	 */
+	public AttributeDeclaration getAttribute(String name) {
+		AttributeDeclaration attribute = attributes.get(name);
+		if (attribute != null) {
+			return attribute;
+		}
+		attribute = new AttributeDeclaration(name);
+		attributes.put(name, attribute);
+		return attribute;
+	}
+
+	public Collection<AttributeDeclaration> getAttributes() {
+		return attributes.values();
+	}
+
+	/**
+	 * Returns true if element has character content and false otherwise.
+	 * 
+	 * @return true if element has character content and false otherwise.
+	 */
+	public boolean hasCharacterContent() {
+		return hasCharacterContent;
+	}
+
+	void setHasCharacterContent(boolean hasCharacterContent) {
+		this.hasCharacterContent = hasCharacterContent;
+	}
+
+	public void incrementOccurrences() {
+		occurrences++;
+	}
+
+	public int getOccurrences() {
+		return occurrences;
+	}
+
+	protected ElementDeclaration createElement(String name) {
+		return new ElementDeclaration(name, this);
+	}
+
+	public ElementDeclaration getParent() {
+		return parent;
+	}
+
+}