[feature] Serialize preserved XML Declaration by default

Author: adamretter

exist-core/src/main/java/org/exist/storage/serializers/EXistOutputKeys.java

@@ -28,7 +28,9 @@ public class EXistOutputKeys {
      */
     public static final String ITEM_SEPARATOR = "item-separator";
 
-	public static final String OUTPUT_DOCTYPE = "output-doctype";
+    public static final String OMIT_ORIGINAL_XML_DECLARATION = "omit-original-xml-declaration";
+
+    public static final String OUTPUT_DOCTYPE = "output-doctype";
 
 	public static final String EXPAND_XINCLUDES = "expand-xincludes";
 

exist-core/src/main/java/org/exist/storage/serializers/NativeSerializer.java

@@ -22,6 +22,7 @@
 package org.exist.storage.serializers;
 
 import org.exist.Namespaces;
+import org.exist.dom.QName;
 import org.exist.dom.persistent.AttrImpl;
 import org.exist.dom.persistent.CDATASectionImpl;
 import org.exist.dom.persistent.CommentImpl;
@@ -32,8 +33,8 @@
 import org.exist.dom.persistent.Match;
 import org.exist.dom.persistent.NodeProxy;
 import org.exist.dom.persistent.ProcessingInstructionImpl;
-import org.exist.dom.QName;
 import org.exist.dom.persistent.TextImpl;
+import org.exist.dom.persistent.XMLDeclarationImpl;
 import org.exist.numbering.NodeId;
 import org.exist.storage.DBBroker;
 import org.exist.util.Configuration;
@@ -116,7 +117,14 @@ protected void serializeToReceiver(DocumentImpl doc, boolean generateDocEvent) t
             documentStarted = true;
         }
 
-        if (doc.getDoctype() != null){
+        if (doc.getXmlDeclaration() != null){
+            if ("no".equals(getProperty(EXistOutputKeys.OMIT_ORIGINAL_XML_DECLARATION, "no"))) {
+                final XMLDeclarationImpl xmlDecl = doc.getXmlDeclaration();
+                receiver.declaration(xmlDecl.getVersion(), xmlDecl.getEncoding(), xmlDecl.getStandalone());
+            }
+        }
+
+        if (doc.getDoctype() != null) {
             if ("yes".equals(getProperty(EXistOutputKeys.OUTPUT_DOCTYPE, "no"))) {
                 final DocumentTypeImpl docType = (DocumentTypeImpl)doc.getDoctype();
                 serializeToReceiver(docType, null, docType.getOwnerDocument(), true, null, new TreeSet<>());

exist-core/src/main/java/org/exist/util/serializer/AbstractSerializer.java

@@ -62,8 +62,9 @@ public abstract class AbstractSerializer {
     protected static final Properties defaultProperties = new Properties();
 
     static {
-        defaultProperties.setProperty(OutputKeys.ENCODING, UTF_8.name());
-        defaultProperties.setProperty(OutputKeys.INDENT, "false");
+        defaultProperties.setProperty(EXistOutputKeys.OMIT_ORIGINAL_XML_DECLARATION, "no");
+        defaultProperties.setProperty(OutputKeys.OMIT_XML_DECLARATION, "no");
+        defaultProperties.setProperty(EXistOutputKeys.XDM_SERIALIZATION, "no");
     }
 
     protected Properties outputProperties;

exist-core/src/main/java/org/exist/util/serializer/XMLWriter.java

@@ -48,10 +48,14 @@ public class XMLWriter implements SerializerWriter {
 
     protected final static Properties defaultProperties = new Properties();
     static {
+        defaultProperties.setProperty(EXistOutputKeys.OMIT_ORIGINAL_XML_DECLARATION, "no");
         defaultProperties.setProperty(OutputKeys.OMIT_XML_DECLARATION, "no");
         defaultProperties.setProperty(EXistOutputKeys.XDM_SERIALIZATION, "no");
     }
 
+    private static final String DEFAULT_XML_VERSION = "1.0";
+    private static final String DEFAULT_XML_ENCODING = UTF_8.name();
+
     protected Writer writer = null;
 
     protected CharacterSet charSet;
@@ -132,7 +136,7 @@ public void setOutputProperties(final Properties properties) {
             outputProperties = properties;
         }
 
-        final String encoding = outputProperties.getProperty(OutputKeys.ENCODING, UTF_8.name());
+        final String encoding = outputProperties.getProperty(OutputKeys.ENCODING, DEFAULT_XML_ENCODING);
         this.charSet = CharacterSet.getCharacterSet(encoding);
         if(this.charSet == null) {
             throw EX_CHARSET_NULL;
@@ -531,11 +535,28 @@ protected void writeDeclaration() throws TransformerException {
             outputProperties = new Properties(defaultProperties);
         }
         declarationWritten = true;
+
         final String omitXmlDecl = outputProperties.getProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
-        if("no".equals(omitXmlDecl)) {
-            final String version = outputProperties.getProperty(OutputKeys.VERSION, "1.0");
-            final String standalone = outputProperties.getProperty(OutputKeys.STANDALONE);
-            final String encoding = outputProperties.getProperty(OutputKeys.ENCODING, UTF_8.name());
+        if ("no".equals(omitXmlDecl)) {
+
+            final String version;
+            final String encoding;
+            @Nullable final String standalone;
+
+            final String omitOriginalXmlDecl = outputProperties.getProperty(EXistOutputKeys.OMIT_ORIGINAL_XML_DECLARATION, "yes");
+            if (originalXmlDecl != null && "no".equals(omitOriginalXmlDecl)) {
+                // get the fields of the persisted xml declaration, but overridden with any properties from the serialization properties
+                version = outputProperties.getProperty(OutputKeys.VERSION, (originalXmlDecl.version != null ? originalXmlDecl.version : DEFAULT_XML_VERSION));
+                encoding = outputProperties.getProperty(OutputKeys.ENCODING, (originalXmlDecl.encoding != null ? originalXmlDecl.encoding : DEFAULT_XML_ENCODING));
+                standalone = outputProperties.getProperty(OutputKeys.STANDALONE, originalXmlDecl.standalone);
+
+            } else {
+                // get the fields of the declaration from the serialization properties
+                version = outputProperties.getProperty(OutputKeys.VERSION, DEFAULT_XML_VERSION);
+                encoding = outputProperties.getProperty(OutputKeys.ENCODING, DEFAULT_XML_ENCODING);
+                standalone = outputProperties.getProperty(OutputKeys.STANDALONE);
+            }
+
             try {
                 writer.write("<?xml version=\"");
                 writer.write(version);