From 9f0b5fdd023bf07764b091288894684637db0e64 Mon Sep 17 00:00:00 2001
From: azerr <azerr@redhat.com>
Date: Wed, 24 Jul 2019 22:44:38 +0200
Subject: [PATCH] Add support for `textDocument/documentHighlight` for DTD

Fixes #545

Signed-off-by: azerr <azerr@redhat.com>
---
 .../eclipse/lsp4xml/dom/DTDElementDecl.java   |  82 ++++++++++++-
 .../lsp4xml/extensions/dtd/DTDPlugin.java     |   8 ++
 .../DTDHighlightingParticipant.java           |  98 +++++++++++++++
 .../extensions/dtd/utils/DTDUtils.java        | 112 +++++++++++++++++-
 4 files changed, 295 insertions(+), 5 deletions(-)
 create mode 100644 org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/dtd/participants/DTDHighlightingParticipant.java

diff --git a/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/dom/DTDElementDecl.java b/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/dom/DTDElementDecl.java
index 27244e8c48..54c27ba635 100644
--- a/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/dom/DTDElementDecl.java
+++ b/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/dom/DTDElementDecl.java
@@ -10,6 +10,8 @@
  */
 package org.eclipse.lsp4xml.dom;
 
+import java.util.function.BiConsumer;
+
 /**
  * DTD Element Declaration <!ELEMENT
  * 
@@ -107,6 +109,59 @@ public DTDDeclParameter getParameterAt(int offset) {
 		return new DTDDeclParameter(this, paramStart, paramEnd);
 	}
 
+	@Override
+	public DTDDeclParameter getReferencedElementNameAt(int offset) {
+		return getParameterAt(offset);
+	}
+
+	/**
+	 * Collect parameters which matches the given target.
+	 * 
+	 * @param target    the target
+	 * @param collector the collector to collect parameters.
+	 */
+	public void collectParameters(DTDDeclParameter target, BiConsumer<DTDDeclParameter, DTDDeclParameter> collector) {
+		DTDDeclParameter name = getNameParameter();
+		if (name == null) {
+			return;
+		}
+		int start = name.getEnd();
+		int end = getEnd();
+
+		String text = getOwnerDocument().getText();
+		text.length();
+		int wordStart = -1;
+		int wordEnd = -1;
+		// Loop for content after <!ELEMENT element-name (
+		// to check if target checks words
+
+		// Ex : if 'svg' is the word to find (the target node)
+		// and we have <!ELEMENT element-name (svg, title, font-face)
+		// we must collect svg as child
+		for (int i = start; i < end; i++) {
+			char c = text.charAt(i);
+			// check if current character is valid for a word.
+			if (isValidChar(c)) {
+				if (wordStart == -1) {
+					// start of the word
+					wordStart = i;
+				}
+			} else if (wordStart != -1) {
+				// current character is not valid, it's the end of the word.
+				wordEnd = i;
+			}
+			if (wordStart != -1 && wordEnd != -1) {
+				// a word was found
+				boolean check = isMatchName(target.getParameter(), text, wordStart, wordEnd);
+				if (check) {
+					collector.accept(new DTDDeclParameter(this, wordStart, wordEnd), target);
+				}
+				wordStart = -1;
+				wordEnd = -1;
+			}
+		}
+	}
+
 	/**
 	 * Returns the start word offset from the <code>from</code> offset to the
 	 * <code>to</code> offse and -1 if no word.
@@ -164,9 +219,30 @@ private static boolean isValidChar(char c) {
 		return Character.isJavaIdentifierPart(c) || c == '-';
 	}
 
-	@Override
-	public DTDDeclParameter getReferencedElementNameAt(int offset) {
-		return getParameterAt(offset);
+	/**
+	 * Returns true if the word in the given <code>text</code> which starts at
+	 * <code>wordStart</code> offset and ends at <code>wordEnd</code> matches the
+	 * given <code>searchWord</code>
+	 * 
+	 * @param searchWord the word to search
+	 * @param text       the text
+	 * @param wordStart  the word start offset
+	 * @param wordEnd    the word end offset
+	 * @return true if the word in the given <code>text</code> which starts at
+	 *         <code>wordStart</code> offset and ends at <code>wordEnd</code>
+	 *         matches the given <code>searchName</code>
+	 */
+	private static boolean isMatchName(String searchWord, String text, int wordStart, int wordEnd) {
+		int length = wordEnd - wordStart;
+		if (searchWord.length() != length) {
+			return false;
+		}
+		for (int j = 0; j < length; j++) {
+			if ((searchWord.charAt(j) != text.charAt(wordStart + j))) {
+				return false;
+			}
+		}
+		return true;
 	}
 
 }
diff --git a/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/dtd/DTDPlugin.java b/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/dtd/DTDPlugin.java
index fc95c94dd1..5416e7d20a 100644
--- a/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/dtd/DTDPlugin.java
+++ b/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/dtd/DTDPlugin.java
@@ -15,8 +15,10 @@
 import org.eclipse.lsp4xml.extensions.contentmodel.model.ContentModelProvider;
 import org.eclipse.lsp4xml.extensions.dtd.contentmodel.CMDTDContentModelProvider;
 import org.eclipse.lsp4xml.extensions.dtd.participants.DTDDefinitionParticipant;
+import org.eclipse.lsp4xml.extensions.dtd.participants.DTDHighlightingParticipant;
 import org.eclipse.lsp4xml.extensions.dtd.participants.diagnostics.DTDDiagnosticsParticipant;
 import org.eclipse.lsp4xml.services.extensions.IDefinitionParticipant;
+import org.eclipse.lsp4xml.services.extensions.IHighlightingParticipant;
 import org.eclipse.lsp4xml.services.extensions.IXMLExtension;
 import org.eclipse.lsp4xml.services.extensions.XMLExtensionsRegistry;
 import org.eclipse.lsp4xml.services.extensions.diagnostics.IDiagnosticsParticipant;
@@ -29,10 +31,12 @@ public class DTDPlugin implements IXMLExtension {
 
 	private final IDiagnosticsParticipant diagnosticsParticipant;
 	private final IDefinitionParticipant definitionParticipant;
+	private IHighlightingParticipant highlightingParticipant;
 
 	public DTDPlugin() {
 		diagnosticsParticipant = new DTDDiagnosticsParticipant();
 		definitionParticipant = new DTDDefinitionParticipant();
+		highlightingParticipant = new DTDHighlightingParticipant();
 	}
 
 	@Override
@@ -50,6 +54,8 @@ public void start(InitializeParams params, XMLExtensionsRegistry registry) {
 		registry.registerDiagnosticsParticipant(diagnosticsParticipant);
 		// register definition participant
 		registry.registerDefinitionParticipant(definitionParticipant);
+		// register highlighting participant
+		registry.registerHighlightingParticipant(highlightingParticipant);
 	}
 
 	@Override
@@ -58,5 +64,7 @@ public void stop(XMLExtensionsRegistry registry) {
 		registry.unregisterDiagnosticsParticipant(diagnosticsParticipant);
 		// unregister definition participant
 		registry.unregisterDefinitionParticipant(definitionParticipant);
+		// unregister highlighting participant
+		registry.unregisterHighlightingParticipant(highlightingParticipant);
 	}
 }
diff --git a/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/dtd/participants/DTDHighlightingParticipant.java b/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/dtd/participants/DTDHighlightingParticipant.java
new file mode 100644
index 0000000000..59cbfd87e0
--- /dev/null
+++ b/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/dtd/participants/DTDHighlightingParticipant.java
@@ -0,0 +1,98 @@
+/*******************************************************************************
+* Copyright (c) 2019 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
+*
+* Contributors:
+*     Red Hat Inc. - initial API and implementation
+*******************************************************************************/
+package org.eclipse.lsp4xml.extensions.dtd.participants;
+
+import java.util.List;
+
+import org.eclipse.lsp4j.DocumentHighlight;
+import org.eclipse.lsp4j.DocumentHighlightKind;
+import org.eclipse.lsp4j.Position;
+import org.eclipse.lsp4j.jsonrpc.CancelChecker;
+import org.eclipse.lsp4xml.dom.DOMNode;
+import org.eclipse.lsp4xml.dom.DTDAttlistDecl;
+import org.eclipse.lsp4xml.dom.DTDDeclParameter;
+import org.eclipse.lsp4xml.dom.DTDElementDecl;
+import org.eclipse.lsp4xml.extensions.dtd.utils.DTDUtils;
+import org.eclipse.lsp4xml.services.extensions.IHighlightingParticipant;
+import org.eclipse.lsp4xml.utils.XMLPositionUtility;
+
+/**
+ * DTD highlight participant
+ * 
+ * @author Angelo ZERR
+ *
+ */
+
+public class DTDHighlightingParticipant implements IHighlightingParticipant {
+
+	@Override
+	public void findDocumentHighlights(DOMNode node, Position position, int offset, List<DocumentHighlight> highlights,
+			CancelChecker cancelChecker) {
+		boolean findReferences = false;
+		DTDDeclParameter parameter = null;
+		DTDElementDecl elementDecl = null;
+
+		if (node.isDTDElementDecl()) {
+			elementDecl = (DTDElementDecl) node;
+			if (elementDecl.isInNameParameter(offset)) {
+				// <!ELEMENT na|me --> here cursor is in the name of <!ELEMENT
+				// we must find all references from the <!ELEMENT which defines the name
+				findReferences = true;
+				parameter = elementDecl.getNameParameter();
+			} else {
+				// <!ELEMENT name (chi|ld --> here cursor is in the child element
+				// we must find only the <!ELEMENT child
+				parameter = elementDecl.getParameterAt(offset);
+			}
+		} else if (node.isDTDAttListDecl()) {
+			DTDAttlistDecl attlistDecl = (DTDAttlistDecl) node;
+			if (attlistDecl.isInNameParameter(offset)) {
+				// <!ATTLIST na|me --> here cusror is in the name of <!ATTLIST
+				// we must find only the <!ELEMENT name
+				parameter = attlistDecl.getNameParameter();
+			}
+		}
+
+		if (parameter == null) {
+			return;
+		}
+
+		if (findReferences) {
+			// case with <!ELEMENT na|me
+
+			// highlight <!ELEMENT na|me
+			DTDDeclParameter originNode = parameter;
+			highlights.add(
+					new DocumentHighlight(XMLPositionUtility.createRange(originNode), DocumentHighlightKind.Write));
+
+			// highlight all references of na|me in ATTLIST and child of <!ELEMENT
+			DTDUtils.searchDTDOriginElementDecls(elementDecl, (origin, target) -> {
+				highlights
+						.add(new DocumentHighlight(XMLPositionUtility.createRange(origin), DocumentHighlightKind.Read));
+			}, cancelChecker);
+		} else {
+			// case with
+			// - <!ELEMENT name (chi|ld
+			// - <!ATTLIST na|me
+
+			// highlight <!ELEMENT name (chi|ld or <!ATTLIST na|me
+			DTDDeclParameter targetNode = parameter;
+			highlights
+					.add(new DocumentHighlight(XMLPositionUtility.createRange(targetNode), DocumentHighlightKind.Read));
+
+			// highlight the target <!ELEMENT nam|e
+			DTDUtils.searchDTDTargetElementDecl(parameter, true, targetName -> {
+				highlights.add(
+						new DocumentHighlight(XMLPositionUtility.createRange(targetName), DocumentHighlightKind.Write));
+			});
+		}
+	}
+
+}
diff --git a/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/dtd/utils/DTDUtils.java b/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/dtd/utils/DTDUtils.java
index eafaf92470..23dfeebb1c 100644
--- a/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/dtd/utils/DTDUtils.java
+++ b/org.eclipse.lsp4xml/src/main/java/org/eclipse/lsp4xml/extensions/dtd/utils/DTDUtils.java
@@ -9,10 +9,16 @@
 *******************************************************************************/
 package org.eclipse.lsp4xml.extensions.dtd.utils;
 
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.BiConsumer;
 import java.util.function.Consumer;
 
+import org.eclipse.lsp4j.jsonrpc.CancelChecker;
 import org.eclipse.lsp4xml.dom.DOMDocumentType;
 import org.eclipse.lsp4xml.dom.DOMNode;
+import org.eclipse.lsp4xml.dom.DTDAttlistDecl;
+import org.eclipse.lsp4xml.dom.DTDDeclNode;
 import org.eclipse.lsp4xml.dom.DTDDeclParameter;
 import org.eclipse.lsp4xml.dom.DTDElementDecl;
 import org.w3c.dom.Node;
@@ -31,8 +37,8 @@ public class DTDUtils {
 	 * node.
 	 * 
 	 * @param originNameNode the origin name node (<ex :<!ATTLIST name).
-	 * @param matchName      true if the attribute value must match the value of
-	 *                       target attribute value and false otherwise.
+	 * @param matchName      true if the origin name must match the value of target
+	 *                       name and false otherwise.
 	 * @param collector      collector to collect DTD <!ELEMENT target name.
 	 */
 	public static void searchDTDTargetElementDecl(DTDDeclParameter originNameNode, boolean matchName,
@@ -59,6 +65,108 @@ public static void searchDTDTargetElementDecl(DTDDeclParameter originNameNode, b
 		}
 	}
 
+	/**
+	 * Search origin DTD node (<!ATTRLIST element-name) or (child <!ELEMENT
+	 * element-name (child)) from the given target DTD node (<!ELEMENT element-name.
+	 * 
+	 * @param targetNode the referenced node
+	 * @param collector  the collector to collect reference between an origin and
+	 *                   target attribute.
+	 */
+	public static void searchDTDOriginElementDecls(DTDDeclNode targetNode,
+			BiConsumer<DTDDeclParameter, DTDDeclParameter> collector, CancelChecker cancelChecker) {
+		// Collect all potential target DTD nodes (all <!ELEMENT)
+		List<DTDDeclNode> targetNodes = getTargetNodes(targetNode);
+		if (targetNodes.isEmpty()) {
+			// None referenced nodes, stop the search of references
+			return;
+		}
+
+		// Loop for each <!ELEMENT and check for each target DTD nodes if it reference
+		// it.
+		DOMDocumentType docType = targetNode.getOwnerDocType();
+		if (docType.hasChildNodes()) {
+			// Loop for <!ELEMENT.
+			NodeList children = docType.getChildNodes();
+			for (int i = 0; i < children.getLength(); i++) {
+				if (cancelChecker != null) {
+					cancelChecker.checkCanceled();
+				}
+				Node origin = children.item(i);
+				for (DTDDeclNode target : targetNodes) {
+					if (target.isDTDElementDecl()) {
+						// target node is <!ELEMENT, check if it is references by the current origin
+						// node
+						DTDElementDecl targetElement = (DTDElementDecl) target;
+						switch (origin.getNodeType()) {
+						case DOMNode.DTD_ELEMENT_DECL_NODE:
+							// check if the current <!ELEMENT origin defines a child which references the
+							// target node <!ELEMENT
+							// <!ELEMENT from > --> here target node is 'from'
+							// <!ELEMENT note(from)> --> here origin node is 'note'
+							// --> here 'note' has a 'from' as child and it should be collected
+							DTDElementDecl originElement = (DTDElementDecl) origin;
+							originElement.collectParameters(targetElement.getNameParameter(), collector);
+							break;
+						case DOMNode.DTD_ATT_LIST_NODE:
+							String name = targetElement.getName();
+							// check if the current <!ATTLIST element-name reference the current <!ELEMENT
+							// element-name
+							// <!ELEMENT note --> here target node is 'note'
+							// <!ATTLIST note ... -> here origin node is 'note'
+							// --> here <!ATTLIST defines 'note' as element name, and it should be collected
+							DTDAttlistDecl originAttribute = (DTDAttlistDecl) origin;
+							if (name.equals(originAttribute.getElementName())) {
+								// <!ATTLIST origin has the same name than <!ELEMENT target
+								collector.accept(originAttribute.getNameParameter(), targetElement.getNameParameter());
+							}
+							break;
+						}
+					}
+				}
+			}
+		}
+	}
+
+	/**
+	 * Returns the referenced attributes list from the given referenced node.
+	 * 
+	 * @param referencedNode the referenced node.
+	 * @return the referenced attributes list from the given referenced node.
+	 */
+	private static List<DTDDeclNode> getTargetNodes(DTDDeclNode referencedNode) {
+		List<DTDDeclNode> referencedNodes = new ArrayList<>();
+		switch (referencedNode.getNodeType()) {
+		case DOMNode.DTD_ELEMENT_DECL_NODE:
+			addTargetNode(referencedNode, referencedNodes);
+			break;
+		case Node.DOCUMENT_TYPE_NODE:
+			DOMDocumentType docType = (DOMDocumentType) referencedNode;
+			if (docType.hasChildNodes()) {
+				// Loop for element <!ELEMENT.
+				NodeList children = docType.getChildNodes();
+				for (int i = 0; i < children.getLength(); i++) {
+					Node node = children.item(i);
+					if (node.getNodeType() == DOMNode.DTD_ELEMENT_DECL_NODE) {
+						addTargetNode((DTDElementDecl) node, referencedNodes);
+					}
+				}
+			}
+			break;
+		}
+		return referencedNodes;
+	}
+
+	private static void addTargetNode(DTDDeclNode referencedNode, List<DTDDeclNode> referencedNodes) {
+		if (referencedNode.isDTDElementDecl()) {
+			// Add only <!ELEMENT which defines a name.
+			DTDElementDecl elementDecl = (DTDElementDecl) referencedNode;
+			if (isValid(elementDecl)) {
+				referencedNodes.add(elementDecl);
+			}
+		}
+	}
+
 	/**
 	 * Returns true if the given <!ELEMENT defines a name and false otherwise.
 	 *