Disable snippets in front of XML declaration.

Fixes #729.

Signed-off-by: Balduin Landolt <[email protected]>

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/dom/DOMDocument.java

@@ -307,6 +307,29 @@ public boolean hasProlog() {
 		return (children != null && !children.isEmpty() && children.get(0).isProlog());
 	}
 
+	/**
+	 * If document has {@code <?xml ... ?>}, return this prolog, null otherwise
+	 * 
+	 * @return prolog DOMNode, if the document has one, null otherwise
+	 */
+	public DOMNode getProlog() {
+		if (hasProlog()) {
+			return getChild(0);
+		} else {
+			return null;
+		}
+	}
+
+	/**
+	 * Returns true, if the given offset is before XML declaration ({@code <?xml ...?>}), false otherwise.
+	 * 
+	 * @param offset the offset position in question
+	 * @return true, if before xml declaration; false otherwise
+	 */
+	public boolean isBeforeProlog(int offset){
+		return hasProlog() && offset <= getProlog().getStart();
+	}
+
 	private static SchemaLocation createSchemaLocation(DOMNode root, String schemaInstancePrefix) {
 		DOMAttr attr = root.getAttributeNode(getPrefixedName(schemaInstancePrefix, "schemaLocation"));
 		if (attr == null) {

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/services/snippets/CommentSnippetContext.java

@@ -13,6 +13,7 @@
 
 import java.util.Map;
 
+import org.eclipse.lemminx.dom.DOMDocument;
 import org.eclipse.lemminx.dom.DOMNode;
 import org.eclipse.lemminx.services.extensions.ICompletionRequest;
 
@@ -36,6 +37,12 @@ public boolean isMatch(ICompletionRequest request, Map<String, String> model) {
 			// completion was triggered inside doctype declaration, ignore the snippets
 			return false;
 		}
+
+		DOMDocument document = request.getXMLDocument();
+		if (document.isBeforeProlog(request.getOffset())){
+			// triggered before prolog
+			return false;
+		}
 		return SnippetContextUtils.canAcceptExpression(request);
 	}
 

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/services/snippets/DocTypeSnippetContext.java

@@ -58,6 +58,11 @@ public boolean isMatch(ICompletionRequest request, Map<String, String> model) {
 			return false;
 		}
 
+		if (document.isBeforeProlog(offset)){
+			// triggered before prolog
+			return false;
+		}
+
 		if (offset > documentElement.getStart()) {
 			return false;
 		}

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/services/snippets/NewFileSnippetContext.java

@@ -63,6 +63,10 @@ public boolean isMatch(ICompletionRequest request, Map<String, String> model) {
 			// --> <?xml version="1.0" encoding="UTF-8" | ?>
 			return false;
 		}
+		if (document.isBeforeProlog(offset)) {
+			// triggered before prolog
+			return false;
+		}
 		// The file contains some contents, the contents allowed are:
 		// - comments
 		// - processing instruction

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/services/snippets/ProcessingInstructionSnippetContext.java

@@ -51,9 +51,9 @@ public boolean isMatch(ICompletionRequest request, Map<String, String> model) {
 			return false;
 		}
 
- 		if (document.hasProlog() && offset == 0){
-			 // triggered before prolog
-			 return false;
+		if (document.isBeforeProlog(offset)){
+			// triggered before prolog
+			return false;
 		}
 
 		if (documentElement != null && documentElement.getTagName() != null) {

org.eclipse.lemminx/src/main/java/org/eclipse/lemminx/services/snippets/XMLDeclarationSnippetContext.java

@@ -37,8 +37,8 @@ public boolean isMatch(ICompletionRequest request, Map<String, String> model) {
 			// --> <?xml version="1.0" encoding="UTF-8" | ?>
 			return false;
 		}
-		// check if document already defined a xml processing instruction.
-		if (hasProlog(document, offset)) {
+		// check if document already defined a xml declaration.
+		if (document.isBeforeProlog(offset) || inProlog(document, offset)) {
 			return false;
 		}
 		Position start = request.getReplaceRange().getStart();
@@ -55,7 +55,7 @@ public boolean isMatch(ICompletionRequest request, Map<String, String> model) {
 		return true;
 	}
 
-	private static boolean hasProlog(DOMDocument document, int offset) {
+	private static boolean inProlog(DOMDocument document, int offset) {
 		DOMNode node = document.getFirstChild();
 		if (node == null) {
 			return false;

org.eclipse.lemminx/src/test/java/org/eclipse/lemminx/services/XMLCompletionSnippetsTest.java

@@ -537,4 +537,57 @@ public void emptyCompletionInsideDOCTYPE() throws BadLocationException {
 		testCompletionFor("<!DOCTYPE root-element |SYSTEM \"file.dtd\">", 0);
 		testCompletionFor("<!DOCTYPE root-element SYSTEM |\"file.dtd\">", 0);
 	}
+
+	// Tests triggering completion at the very beginning of the file.
+	// Should be possible if not in front of the xml declaration.
+	@Test
+	public void atBeginningOfFile() throws BadLocationException{
+		// No Completion when triggered in front of xml declaration.
+		// Only XML declaration
+		String xml = "|<?xml version=\"1.0\" encoding=\"UTF-8\" ?>";
+		testCompletionFor(xml, 0);
+		// Space before declaration; triggered before space
+		xml = "| <?xml version=\"1.0\" encoding=\"UTF-8\" ?>";
+		testCompletionFor(xml, REGION_SNIPPETS); // FIXME: region snippets should not trigger here.
+		// Space before declaration; triggered after space
+		xml = " |<?xml version=\"1.0\" encoding=\"UTF-8\" ?>";
+		testCompletionFor(xml, REGION_SNIPPETS); // FIXME: region snippets should not trigger here.
+		// Declaration and a root element
+		xml = "|<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\r\n" + //
+				"<root/>";
+		testCompletionFor(xml, 0);
+		// Space before declaration; triggered before space
+		xml = "| <?xml version=\"1.0\" encoding=\"UTF-8\" ?>\r\n" + //
+				"<root/>";
+		testCompletionFor(xml, REGION_SNIPPETS); // FIXME: region snippets should not trigger here.
+		// Space before declaration; triggered after space
+		xml = " |<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\r\n" + //
+				"<root/>";
+		testCompletionFor(xml, REGION_SNIPPETS); // FIXME: region snippets should not trigger here.
+
+		// Multiple Snippets can be triggered at start of file, if it doesn't have an xml declaration
+		xml = "|\r\n" + //
+				"<root/>";
+		testCompletionFor(xml, //
+				COMMENT_SNIPPETS /* Comment Snippets */ + //
+				XML_DECLARATION_SNIPPETS /* XML Declaration Snippets */ + //
+				PROCESSING_INSTRUCTION_SNIPPETS /* Processing Instruction Snippets */ + //
+				DOCTYPE_SNIPPETS /* Doctype Snippets */ + //
+				REGION_SNIPPETS /* Region Snippets */, //
+				c("Insert XML Declaration", //
+						"<?xml version=\"1.0\" encoding=\"UTF-8\"?>", //
+						r(0, 0, 0, 0), "<?xml"),
+				c("Insert XML Schema association", //
+						"<?xml-model href=\"file.xsd\" type=\"application/xml\" schematypens=\"http://www.w3.org/2001/XMLSchema\"?>", //
+						r(0, 0, 0, 0), "<?xml-model"),
+				c("Insert DTD association", //
+						"<?xml-model href=\"file.dtd\" type=\"application/xml-dtd\"?>", //
+						r(0, 0, 0, 0), "<?xml-model"),
+				c("Insert SYSTEM DOCTYPE", //
+						"<!DOCTYPE root SYSTEM \"file.dtd\">", //
+						r(0, 0, 0, 0), "<!DOCTYPE"),
+				c("<!--", //
+						"<!-- -->", //
+						r(0, 0, 0, 0), "<!--"));
+	}
 }