Completion provides invalid suggestions for xsd:sequence

Fix #347

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

org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/contentmodel/model/CMDocument.java

@@ -13,6 +13,7 @@
 import java.util.Collection;
 
 import org.eclipse.lsp4xml.dom.DOMElement;
+import org.w3c.dom.Element;
 
 /**
  * Content model document which abstracts element declaration from a given

org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/contentmodel/model/CMElementDeclaration.java

@@ -12,6 +12,8 @@
 
 import java.util.Collection;
 
+import org.eclipse.lsp4xml.dom.DOMElement;
+
 /**
  * Content model element which abstracts element declaration from a given
  * grammar (XML Schema, DTD).
@@ -59,6 +61,14 @@ default String getName(String prefix) {
 	 */
 	Collection<CMElementDeclaration> getElements();
 
+	/**
+	 * Returns the possible declared elements for the given DOM after element.
+	 * 
+	 * @param afterElement the after element
+	 * @return the possible declared elements for the given DOM after element.
+	 */
+	Collection<CMElementDeclaration> getPossibleElements(DOMElement afterElement);
+
 	/**
 	 * Returns the declared element which matches the given XML tag name / namespace
 	 * and null otherwise.

org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/contentmodel/participants/ContentModelCompletionParticipant.java

@@ -20,6 +20,7 @@
 import org.eclipse.lsp4xml.commons.BadLocationException;
 import org.eclipse.lsp4xml.dom.DOMDocument;
 import org.eclipse.lsp4xml.dom.DOMElement;
+import org.eclipse.lsp4xml.dom.DOMNode;
 import org.eclipse.lsp4xml.extensions.contentmodel.model.CMAttributeDeclaration;
 import org.eclipse.lsp4xml.extensions.contentmodel.model.CMDocument;
 import org.eclipse.lsp4xml.extensions.contentmodel.model.CMElementDeclaration;
@@ -66,10 +67,18 @@ public void onTagOpen(ICompletionRequest request, ICompletionResponse response)
 			CMElementDeclaration cmElement = contentModelManager.findCMElement(parentElement);
 			String defaultPrefix = null;
 
+			// get the previous sibling element to filter completion according XML Schema
+			// constraints.
+			DOMElement previousSiblingElement = null;
+			DOMNode previousSibling = request.getNode();// .getPreviousSibling();
+			if (previousSibling != null && previousSibling.isElement() && !previousSibling.equals(parentElement)
+					&& previousSibling.isClosed()) {
+				previousSiblingElement = (DOMElement) previousSibling;
+			}
 			if (cmElement != null) {
 				defaultPrefix = parentElement.getPrefix();
-				fillWithChildrenElementDeclaration(parentElement, cmElement.getElements(), defaultPrefix, false,
-						request, response, schemaURI);
+				fillWithChildrenElementDeclaration(parentElement, cmElement.getPossibleElements(previousSiblingElement),
+						defaultPrefix, false, request, response, schemaURI);
 			}
 			if (parentElement.isDocumentElement()) {
 				// completion on root document element
@@ -95,8 +104,9 @@ public void onTagOpen(ICompletionRequest request, ICompletionResponse response)
 			CMElementDeclaration cmInternalElement = contentModelManager.findInternalCMElement(parentElement);
 			if (cmInternalElement != null) {
 				defaultPrefix = parentElement.getPrefix();
-				fillWithChildrenElementDeclaration(parentElement, cmInternalElement.getElements(), defaultPrefix, false,
-						request, response, schemaURI);
+				fillWithChildrenElementDeclaration(parentElement,
+						cmInternalElement.getPossibleElements(previousSiblingElement), defaultPrefix, false, request,
+						response, schemaURI);
 			}
 		} catch (CacheResourceDownloadingException e) {
 			// XML Schema, DTD is loading, ignore this error

org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/dtd/contentmodel/CMDTDElementDeclaration.java

@@ -15,6 +15,7 @@
 import java.util.List;
 
 import org.apache.xerces.impl.dtd.XMLElementDecl;
+import org.eclipse.lsp4xml.dom.DOMElement;
 import org.eclipse.lsp4xml.extensions.contentmodel.model.CMAttributeDeclaration;
 import org.eclipse.lsp4xml.extensions.contentmodel.model.CMElementDeclaration;
 
@@ -62,6 +63,12 @@ public Collection<CMElementDeclaration> getElements() {
 		return elements;
 	}
 
+	@Override
+	public Collection<CMElementDeclaration> getPossibleElements(DOMElement afterElement) {
+		// TODO: support valid element declaration for DTD
+		return getElements();
+	}
+
 	@Override
 	public CMElementDeclaration findCMElement(String tag, String namespace) {
 		for (CMElementDeclaration cmElement : getElements()) {

org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/xsd/contentmodel/CMXSDDocument.java

@@ -18,6 +18,9 @@
 import java.util.Map;
 
 import org.apache.xerces.impl.dv.XSSimpleType;
+import org.apache.xerces.impl.xs.XSElementDecl;
+import org.apache.xerces.impl.xs.XSElementDeclHelper;
+import org.apache.xerces.xni.QName;
 import org.apache.xerces.xs.StringList;
 import org.apache.xerces.xs.XSConstants;
 import org.apache.xerces.xs.XSElementDeclaration;
@@ -35,7 +38,7 @@
  * XSD document implementation.
  *
  */
-public class CMXSDDocument implements CMDocument {
+public class CMXSDDocument implements CMDocument, XSElementDeclHelper {
 
 	private final XSModel model;
 
@@ -173,4 +176,9 @@ static boolean isBooleanType(XSSimpleTypeDefinition typeDefinition) {
 		}
 		return false;
 	}
+
+	@Override
+	public XSElementDecl getGlobalElementDecl(QName element) {
+		return (XSElementDecl) model.getElementDeclaration(element.localpart, element.uri);
+	}
 }

org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/xsd/contentmodel/CMXSDElementDeclaration.java

@@ -13,9 +13,16 @@
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.List;
+import java.util.Vector;
 
 import org.apache.xerces.impl.dv.xs.XSSimpleTypeDecl;
+import org.apache.xerces.impl.xs.SubstitutionGroupHandler;
 import org.apache.xerces.impl.xs.XSComplexTypeDecl;
+import org.apache.xerces.impl.xs.models.CMBuilder;
+import org.apache.xerces.impl.xs.models.CMNodeFactory;
+import org.apache.xerces.impl.xs.models.XSCMValidator;
+import org.apache.xerces.xni.QName;
 import org.apache.xerces.xs.XSAttributeUse;
 import org.apache.xerces.xs.XSComplexTypeDefinition;
 import org.apache.xerces.xs.XSConstants;
@@ -27,15 +34,38 @@
 import org.apache.xerces.xs.XSSimpleTypeDefinition;
 import org.apache.xerces.xs.XSTerm;
 import org.apache.xerces.xs.XSTypeDefinition;
+import org.eclipse.lsp4xml.dom.DOMElement;
 import org.eclipse.lsp4xml.extensions.contentmodel.model.CMAttributeDeclaration;
 import org.eclipse.lsp4xml.extensions.contentmodel.model.CMElementDeclaration;
+import org.eclipse.lsp4xml.utils.StringUtils;
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
 
 /**
  * XSD element declaration implementation.
  *
  */
 public class CMXSDElementDeclaration implements CMElementDeclaration {
 
+	private static class QNameInfo extends QName {
+
+		private int count;
+
+		public QNameInfo(String prefix, String localpart, String rawname, String uri) {
+			super(prefix, localpart, rawname, uri);
+			increment();
+		}
+
+		public void increment() {
+			count++;
+		}
+
+		public int getCount() {
+			return count;
+		}
+	}
+
 	private final CMXSDDocument document;
 
 	private final XSElementDeclaration elementDeclaration;
@@ -107,6 +137,117 @@ public Collection<CMElementDeclaration> getElements() {
 		return elements;
 	}
 
+	@Override
+	public Collection<CMElementDeclaration> getPossibleElements(DOMElement afterElement) {
+		XSTypeDefinition typeDefinition = elementDeclaration.getTypeDefinition();
+		if (typeDefinition != null && typeDefinition.getTypeCategory() == XSTypeDefinition.COMPLEX_TYPE) {
+			// The type definition is complex (ex: xs:all; xs:sequence), returns list of
+			// element declaration according those constraint
+
+			// compute list of QName from the parent element of after element to the after
+			// element
+			List<QNameInfo> qnames = new ArrayList<>();
+			if (afterElement != null) {
+				QNameInfo last = null;
+				DOMElement parent = afterElement.getParentElement();
+				NodeList children = parent.getChildNodes();
+				for (int i = 0; i < children.getLength(); i++) {
+					Node child = children.item(i);
+					if (child.getNodeType() == Node.ELEMENT_NODE) {
+						Element element = (Element) child;
+						if (last != null && last.localpart.equals(element.getLocalName())) {
+							last.increment();
+						} else {
+							last = createQName((Element) child);
+							qnames.add(last);
+						}
+						if (child.equals(afterElement)) {
+							break;
+						}
+					}
+				}
+			}
+
+			// Compute list of possible elements
+			Collection<CMElementDeclaration> possibleElements = new ArrayList<>();
+			CMBuilder cmBuilder = new CMBuilder(new CMNodeFactory());
+			XSCMValidator validator = cmBuilder.getContentModel((XSComplexTypeDecl) typeDefinition, true);
+			int[] states = validator.startContentModel();
+			// Get list of XSElementDeclaration according the XML Schema constraints and
+			// QNames list
+			Vector<?> result = whatCanGoHere(validator, states, qnames, 0);
+			if (result != null) {
+				QNameInfo last = qnames.size() > 0 ? qnames.get(qnames.size() - 1) : null;
+				for (Object object : result) {
+					if (object instanceof XSElementDeclaration) {
+						XSElementDeclaration elementDecl = (XSElementDeclaration) object;
+						// check if DOM element match element declaration occurences
+						if (last != null && last.localpart.equals(elementDecl.getName())) {
+							final int[] occurenceInfo = validator.occurenceInfo(states);
+							if (occurenceInfo != null && occurenceInfo[1] <= last.count) {
+								continue;
+							}
+						}
+						document.collectElement(elementDecl, possibleElements);
+					}
+				}
+			}
+			return possibleElements;
+		}
+		return getElements();
+	}
+
+	/**
+	 * Loop for each qnames and return list of possible element declarations.
+	 * 
+	 * @param validator the validator
+	 * @param states    the states
+	 * @param qnames    the list of QNames
+	 * @param index     current index of QName
+	 * @return
+	 */
+	private Vector<?> whatCanGoHere(XSCMValidator validator, int[] states, List<QNameInfo> qnames, int index) {
+		if (qnames.size() <= index) {
+			return validator.whatCanGoHere(states);
+		}
+		// Get current QName
+		QNameInfo current = qnames.get(index);
+		// Loop for possible elements declaration
+		Vector<?> result = validator.whatCanGoHere(states);
+		for (Object object : result) {
+			if (object instanceof XSElementDeclaration) {
+				// check if possible element declaration match the current QName
+				XSElementDeclaration elementDecl = (XSElementDeclaration) object;
+				if (!current.localpart.equals(elementDecl.getName())) {
+					continue;
+				}
+				// check occurences
+				final int[] occurenceInfo = validator.occurenceInfo(states);
+				if (occurenceInfo != null
+						&& !(occurenceInfo[0] <= current.count && occurenceInfo[1] >= current.count)) {
+					return null;
+				}
+				index++;
+				if (qnames.size() < index) {
+					return null;
+				}
+				// get the next element declaration and continue the process
+				validator.oneTransition(current, states, new SubstitutionGroupHandler(document));
+				return whatCanGoHere(validator, states, qnames, index);
+			}
+		}
+		return null;
+	}
+
+	private static QNameInfo createQName(Element tag) {
+		// intern must be called since Xerces uses == to compare String ?
+		// -> see
+		// https://github.com/apache/xerces2-j/blob/trunk/src/org/apache/xerces/impl/xs/SubstitutionGroupHandler.java#L55
+		String namespace = tag.getNamespaceURI();
+		return new QNameInfo(tag.getPrefix(), tag.getLocalName().intern(), tag.getTagName().intern(),
+				StringUtils.isEmpty(namespace) ? null : namespace.intern());
+	}
+
 	private void collectElementsDeclaration(XSElementDeclaration elementDecl,
 			Collection<CMElementDeclaration> elements) {
 		XSTypeDefinition typeDefinition = elementDecl.getTypeDefinition();

org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/services/AbstractPositionRequest.java

@@ -52,15 +52,17 @@ public DOMNode getNode() {
 	@Override
 	public DOMElement getParentElement() {
 		DOMNode currentNode = getNode();
-		if (!currentNode.isElement() || currentNode.getEnd() < offset) {
+		if (!currentNode.isElement()) {
 			// Node is not an element, search parent element.
 			return currentNode.getParentElement();
 		}
 		DOMElement element = (DOMElement) currentNode;
-		// node is an element, there are 2 cases
-		// case 1: <| or <bean | > --> in this case we must search parent of bean
-		// element
-		if (element.isInStartTag(offset) || element.isInEndTag(offset)) {
+		// node is an element, there are 3 cases
+		// - case 1: <|
+		// - case 2: <bean | >
+		// - case 3: <bean /> | or <bean></bean> |
+		// --> in thoses cases we must search parent of bean element
+		if (element.isInStartTag(offset) || element.isInEndTag(offset) || (element.hasEndTag() && element.getEnd() <= offset)) {
 			return element.getParentElement();
 		}
 		// case 2: <bean> | --> in this case, parent element is the bean

org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/services/XMLCompletions.java

@@ -491,7 +491,7 @@ private void collectOpenTagSuggestions(boolean hasOpenBracket, Range replaceRang
 			}
 		}
 		DOMElement parentNode = completionRequest.getParentElement();
-		if (parentNode != null && !completionResponse.hasSomeItemFromGrammar()) {
+		if (parentNode != null && !parentNode.getOwnerDocument().hasGrammar()) {
 			// no grammar, collect similar tags from the parent node
 			Set<String> seenElements = new HashSet<>();
 			if (parentNode != null && parentNode.isElement() && parentNode.hasChildNodes()) {

org.eclipse.lsp4xml/src/test/java/org/eclipse/lsp4xml/extensions/catalog/XMLCatalogExtensionTest.java

@@ -31,7 +31,7 @@ public void completion() throws BadLocationException {
 				"<catalog xmlns=\"urn:oasis:names:tc:entity:xmlns:xml:catalog\">\r\n" + //
 				"    |";
 
-		XMLAssert.testCompletionFor(xml, 16, c("public", "<public publicId=\"\" uri=\"\" />"));
+		XMLAssert.testCompletionFor(xml, 15, c("public", "<public publicId=\"\" uri=\"\" />"));
 	}
 
 	@Test