Allow <![CDATA[]]> to preserve whitespace in XML text content

Add a new constructor parameter (an enum XMLTextEscapeStyle with
Standard and CDATA as values) to XMLTextInfosetOutputter. When CDATA is
passed instead of Standard, wrap simple XML elements' text contents in
CDATA brackets to preserve any whitespace they contain.

DAFFODIL-2346

Author: OWL-Varun

daffodil-japi/src/main/java/org/apache/daffodil/japi/infoset/XMLTextEscapeStyle.java

@@ -0,0 +1,37 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.daffodil.japi.infoset;
+
+/**
+ * XMLTextEscapeStyles for determining whether to wrap info in CDATA tags
+ */
+public enum XMLTextEscapeStyle {
+  /**
+   * Special characters (quotation mark, ampersand, less-than, greater-than) in the
+   * text of xs:string elements are escaped, while non-special characters are written
+   * as is.
+   */
+  Standard,
+
+  /**
+   * The text of xs:string elements are wrapped in CDATA tags if the string contains
+   * special characters (quotation mark, ampersand, less-than, greater-than) or
+   * whitespace
+   */
+  CDATA,
+}

daffodil-japi/src/main/scala/org/apache/daffodil/japi/infoset/Infoset.scala

@@ -40,6 +40,8 @@ import org.apache.daffodil.infoset.DIComplex
 import org.apache.daffodil.infoset.DIArray
 import org.apache.daffodil.dpath.NodeInfo
 
+import org.apache.daffodil.japi.packageprivate._
+
 /**
  * Abstract class used to determine how the infoset representation should be
  * input from a call to DataProcessor#unparse. This uses a Cursor API, such
@@ -52,7 +54,7 @@ abstract class InfosetInputter extends SInfosetInputter {
   /**
    * Return the current infoset inputter event type
    */
-  def getEventType(): InfosetInputterEventType 
+  def getEventType(): InfosetInputterEventType
 
   /**
    * Get the local name of the current event. This will only be called when the
@@ -211,7 +213,7 @@ abstract class InfosetOutputter extends SInfosetOutputter {
  * classes, we can document these classes and have a small and clean javadoc.
  */
 
- 
+
 /**
  * [[InfosetOutputter]] to build an infoset represented as a scala.xml.Node
  *
@@ -244,7 +246,23 @@ class XMLTextInfosetOutputter private (outputter: SXMLTextInfosetOutputter)
    *               insert indentation and newlines where it will not affect the
    *               content of the XML.
    */
-  def this(os: java.io.OutputStream, pretty: Boolean) = this(new SXMLTextInfosetOutputter(os, pretty))
+  def this(os: java.io.OutputStream, pretty: Boolean) = this(new SXMLTextInfosetOutputter(os,
+    pretty, XMLTextEscapeStyleConversions.styleToScala(XMLTextEscapeStyle.Standard)))
+
+  /**
+   * Output the infoset as XML Text, written to a java.io.OutputStream
+   *
+   * @param os the java.io.OutputStream to write the XML text to
+   * @param pretty enable or disable pretty printing. Pretty printing will only
+   *               insert indentation and newlines where it will not affect the
+   *               content of the XML.
+   * @param xmlTextEscapeStyle determine whether to wrap values of elements of type
+   *                       xs:string in CDATA tags in order to preserve
+   *                       whitespace.
+   */
+  def this(os: java.io.OutputStream, pretty: Boolean, xmlTextEscapeStyle: XMLTextEscapeStyle) = {
+    this(new SXMLTextInfosetOutputter(os, pretty, XMLTextEscapeStyleConversions.styleToScala(xmlTextEscapeStyle)))
+  }
 
   override val infosetOutputter = outputter
 }

daffodil-japi/src/main/scala/org/apache/daffodil/japi/packageprivate/Utils.scala

@@ -30,6 +30,9 @@ import org.apache.daffodil.api.{ ValidationMode => SValidationMode }
 import org.apache.daffodil.debugger.{ InteractiveDebugger => SInteractiveDebugger }
 import org.apache.daffodil.debugger.{ InteractiveDebuggerRunner => SInteractiveDebuggerRunner }
 
+import org.apache.daffodil.infoset.{ XMLTextEscapeStyle => SXMLTextEscapeStyle }
+import org.apache.daffodil.japi.infoset._
+
 private[japi] object ValidationConversions {
 
   def modeToScala(mode: ValidationMode): SValidationMode.Type = {
@@ -42,6 +45,18 @@ private[japi] object ValidationConversions {
   }
 }
 
+private[japi] object XMLTextEscapeStyleConversions {
+
+  def styleToScala(style: XMLTextEscapeStyle): SXMLTextEscapeStyle.Value = {
+    val sxmlTextEscapeStyle: SXMLTextEscapeStyle.Value = style match {
+      case XMLTextEscapeStyle.Standard => SXMLTextEscapeStyle.Standard
+      case XMLTextEscapeStyle.CDATA => SXMLTextEscapeStyle.CDATA
+      case _ => throw new Exception("Unrecognized value: %s for parameter: xmlTextEscapeStyle. Must be 'Standard' or 'CDATA'.".format(style))
+    }
+    sxmlTextEscapeStyle
+  }
+}
+
 /* A wrapper interctive debugger that scala debugging can talk to, which is
  * then forwarded onto the java interactive debugger, if a user implements
  * their own debugger in java.

daffodil-japi/src/test/java/org/apache/daffodil/example/TestJavaAPI.java

@@ -53,6 +53,9 @@
 
 import javax.xml.XMLConstants;
 
+import java.nio.charset.StandardCharsets;
+import org.apache.daffodil.japi.infoset.*;
+
 public class TestJavaAPI {
 
     /**
@@ -262,7 +265,7 @@ public void testJavaAPI2() throws IOException, ClassNotFoundException {
 
     /**
      * Verify that we can detect when the parse did not consume all the data.
-     * 
+     *
      * @throws IOException
      */
     @Test
@@ -393,7 +396,7 @@ public void testJavaAPI5() throws IOException, ClassNotFoundException {
     /***
      * Verify that the compiler throws a FileNotFound exception when fed a list
      * of schema files that do not exist.
-     * 
+     *
      * @throws IOException
      */
     @Test
@@ -415,7 +418,7 @@ public void testJavaAPI6() throws IOException {
     /**
      * Tests a user submitted case where the XML appears to be serializing odd
      * xml entities into the output.
-     * 
+     *
      * @throws IOException
      */
     @Test
@@ -452,7 +455,7 @@ public void testJavaAPI7() throws IOException, ClassNotFoundException {
      * that this test uses double newline as a terminator for the first element
      * in the sequence rather than double newline as a separator for the
      * sequence
-     * 
+     *
      * @throws IOException
      */
     @Test
@@ -931,7 +934,6 @@ public void testJavaAPI20() throws IOException, ClassNotFoundException {
         assertEquals("42", unparseBos.toString());
     }
 
-
     @Test
     public void testJavaAPI21() throws IOException, ClassNotFoundException {
         // Test SAX parsing with errors
@@ -1213,4 +1215,81 @@ public void testJavaAPI26() throws IOException, ClassNotFoundException, External
         assertTrue(DaffodilXMLEntityResolver.getXMLEntityResolver() != null);
         assertTrue(DaffodilXMLEntityResolver.getLSResourceResolver() != null);
     }
+
+    @Test
+    public void testJavaAPINullXMLTextEscapeStyle() throws IOException, ClassNotFoundException {
+        ByteArrayOutputStream xmlBos = new ByteArrayOutputStream();
+        try {
+            XMLTextInfosetOutputter outputter = new XMLTextInfosetOutputter(xmlBos, true, null);
+        } catch (Exception e) {
+            String msg = e.getMessage().toLowerCase();
+            assertTrue(msg.contains("unrecognized"));
+            assertTrue(msg.contains("null"));
+            assertTrue(msg.contains("xmltextescapestyle"));
+        }
+    }
+
+    @Test
+    public void testJavaAPICDATA1() throws IOException, ClassNotFoundException {
+        String expected = "NO_WHITESPACE_OR_SPECIAL_CHARS";
+        String data = "NO_WHITESPACE_OR_SPECIAL_CHARS$";
+        String schemaType = "string";
+        doXMLTextEscapeStyleTest(expected, data, schemaType);
+    }
+
+    @Test
+    public void testJavaAPICDATA2() throws IOException, ClassNotFoundException {
+        String expected = "<![CDATA[   'some' stuff   here &#xE000; and ]]]]><![CDATA[> even]]>";
+        String data = "   'some' stuff   here &#xE000; and ]]> even$";
+        String schemaType = "string";
+        doXMLTextEscapeStyleTest(expected, data, schemaType);
+    }
+
+    @Test
+    public void testJavaAPICDATA3() throws IOException, ClassNotFoundException {
+        String expected = "6.892";
+        String data = "6.892";
+        String schemaType = "float";
+        doXMLTextEscapeStyleTest(expected, data, schemaType);
+    }
+
+    @Test
+    public void testJavaAPICDATA4() throws IOException, ClassNotFoundException {
+        String expected = "<![CDATA[this contains a CRLF\nline ending]]>";
+        String data = "this contains a CRLF\r\nline ending$";
+        String schemaType = "string";
+        doXMLTextEscapeStyleTest(expected, data, schemaType);
+    }
+
+    @Test
+    public void testJavaAPICDATA5() throws IOException, ClassNotFoundException {
+        String expected = "<![CDATA[abcd&gt]]>";
+        String data = "abcd&gt$";
+        String schemaType = "string";
+        doXMLTextEscapeStyleTest(expected, data, schemaType);
+    }
+
+    public void doXMLTextEscapeStyleTest(String expect, String data, String schemaType)
+        throws IOException, ClassNotFoundException {
+
+        org.apache.daffodil.japi.Compiler c = Daffodil.compiler();
+        java.io.File schemaFile = getResource("/test/japi/mySchemaCDATA.dfdl.xsd");
+        ProcessorFactory pf = c.compileFile(schemaFile, schemaType, null);
+        DataProcessor dp = pf.onPath("/");
+
+        ByteArrayInputStream is = new ByteArrayInputStream(data.getBytes(StandardCharsets.UTF_8));
+        InputSourceDataInputStream input = new InputSourceDataInputStream(is);
+        ByteArrayOutputStream bosDP = new ByteArrayOutputStream();
+        XMLTextInfosetOutputter outputter = new XMLTextInfosetOutputter(bosDP, true, XMLTextEscapeStyle.CDATA);
+        ParseResult res = dp.parse(input, outputter);
+        boolean err = res.isError();
+
+        String infosetDPString = bosDP.toString();
+        int start = infosetDPString.indexOf(".com\">") + 6;
+        int end = infosetDPString.indexOf("</tns");
+        String value = infosetDPString.substring(start, end);
+
+        assertFalse(err);
+        assertEquals(expect, value);
+    }
 }

daffodil-japi/src/test/resources/test/japi/mySchemaCDATA.dfdl.xsd

@@ -0,0 +1,41 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  Licensed to the Apache Software Foundation (ASF) under one or more
+  contributor license agreements.  See the NOTICE file distributed with
+  this work for additional information regarding copyright ownership.
+  The ASF licenses this file to You under the Apache License, Version 2.0
+  (the "License"); you may not use this file except in compliance with
+  the License.  You may obtain a copy of the License at
+
+      http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License.
+-->
+
+<schema xmlns="http://www.w3.org/2001/XMLSchema"
+  targetNamespace="http://example.com" xmlns:dfdl="http://www.ogf.org/dfdl/dfdl-1.0/"
+  xmlns:xsd="http://www.w3.org/2001/XMLSchema"
+  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tns="http://example.com">
+
+  <annotation>
+    <appinfo source="http://www.ogf.org/dfdl/">
+      <dfdl:format ref="tns:GeneralFormat" />
+    </appinfo>
+  </annotation>
+
+  <include schemaLocation="org/apache/daffodil/xsd/DFDLGeneralFormat.dfdl.xsd"/>
+
+  <element name="string" type="xsd:string" dfdl:lengthKind="delimited" dfdl:terminator="$"/>
+  <element name="float" type="xsd:float"
+    dfdl:representation="text"
+    dfdl:textNumberRep="standard"
+    dfdl:lengthKind="delimited"
+    dfdl:encoding="UTF-8"
+    dfdl:textNumberPattern="0.000"
+    dfdl:textStandardDecimalSeparator="." />
+
+</schema>

daffodil-runtime1/src/main/scala/org/apache/daffodil/infoset/XMLTextEscapeStyle.scala

@@ -0,0 +1,33 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.daffodil.infoset
+/**
+ * XMLTextEscapeStyle determines how to wrap values of elements of type xs:string
+ *
+ * Standard - Special characters (quotation mark, ampersand, less-than, greater-than)
+ * in the text of xs:string elements are escaped, while non-special characters are
+ * written as is.
+ *
+ * CDATA - The text of xs:string elements are wrapped in CDATA tags if the string
+ * contains whitespace or special characters (quotation mark, ampersand, less-than,
+ * greater-than)
+ */
+object XMLTextEscapeStyle extends Enumeration {
+  type XMLTextEscapeStyle = Value
+  val Standard, CDATA = Value
+}

daffodil-runtime1/src/main/scala/org/apache/daffodil/infoset/XMLTextInfosetOutputter.scala

@@ -31,12 +31,16 @@ import org.apache.daffodil.util.Indentable
  * @param writer The writer to write the XML text to
  * @param pretty Whether or to enable pretty printing. Set to true, XML
  *               elements are indented and newlines are inserted.
+ * @param xmlTextEscapeStyle Determine whether to wrap values of elements of type
+ *        xs:string in CDATA tags in order to preserve whitespace.
  */
-class XMLTextInfosetOutputter private (writer: java.io.Writer, pretty: Boolean)
+class XMLTextInfosetOutputter private (writer: java.io.Writer, pretty: Boolean,
+  xmlTextEscapeStyle: XMLTextEscapeStyle.Value)
   extends InfosetOutputter with Indentable with XMLInfosetOutputter {
 
-  def this(os: java.io.OutputStream, pretty: Boolean) = {
-    this(new java.io.OutputStreamWriter(os, StandardCharsets.UTF_8), pretty)
+  def this(os: java.io.OutputStream, pretty: Boolean,
+    xmlTextEscapeStyle: XMLTextEscapeStyle.Value = XMLTextEscapeStyle.Standard) = {
+    this(new java.io.OutputStreamWriter(os, StandardCharsets.UTF_8), pretty, xmlTextEscapeStyle)
   }
 
   private val sb = new StringBuilder()
@@ -160,7 +164,21 @@ class XMLTextInfosetOutputter private (writer: java.io.Writer, pretty: Boolean)
         if (simple.erd.runtimeProperties.get(XMLTextInfoset.stringAsXml) == "true") {
           writeStringAsXml(simpleVal)
         } else {
-          writer.write(scala.xml.Utility.escape(remapped(simpleVal)))
+          val xmlSafe = remapped(simpleVal)
+          val escaped = xmlTextEscapeStyle match {
+            case XMLTextEscapeStyle.CDATA => {
+              val needsCDataEscape = xmlSafe.exists { c =>
+                scala.xml.Utility.Escapes.escMap.contains(c) || c.isWhitespace
+              }
+              if (needsCDataEscape) {
+                "<![CDATA[%s]]>".format(xmlSafe.replaceAll("]]>", "]]]]><![CDATA[>"))
+              } else {
+                xmlSafe
+              }
+            }
+            case XMLTextEscapeStyle.Standard => scala.xml.Utility.escape(xmlSafe)
+          }
+          writer.write(escaped)
         }
       } else {
         writer.write(simple.dataValueAsString)
@@ -170,7 +188,7 @@ class XMLTextInfosetOutputter private (writer: java.io.Writer, pretty: Boolean)
     outputEndTag(simple)
     inScopeComplexElementHasChildren = true
   }
-  
+
   override def endSimple(simple: DISimple): Unit = {
     // do nothing, everything is done in startSimple
   }