[feature] fn:transform post-process function

Read the post-process parameter, and if it is supplied and is a function, apply it to the output of the transformation as a final step in generating the output of fn:transform.

The post-process function is applied possibly multiple times, once to the main output and once to every secondary output document. The final result is a map with the same keys as before post processing, but with post processed transformed values replacing transformed values.

Author: alanpaxton

exist-core/src/main/java/org/exist/xquery/functions/fn/FnTransform.java

@@ -25,6 +25,7 @@
 import com.evolvedbinary.j8fu.tuple.Tuple2;
 import com.github.benmanes.caffeine.cache.Cache;
 import com.github.benmanes.caffeine.cache.Caffeine;
+import com.github.krukow.clj_lang.PersistentTreeMap;
 import io.lacuna.bifurcan.IEntry;
 import net.jpountz.xxhash.XXHash64;
 import net.jpountz.xxhash.XXHashFactory;
@@ -516,12 +517,13 @@ private MapType makeResultMap(final Options options, final Delivery delivery, fi
             outputKey = new StringValue("output");
         }
 
-        final Sequence primaryValue = convertToDeliveryFormat(options, delivery);
+        final Sequence primaryValue = postProcess(outputKey, convertToDeliveryFormat(options, delivery), options.postProcess);
         outputMap.add(outputKey, primaryValue);
 
         for (final Map.Entry<URI, Delivery> resultDocument : resultDocuments.entrySet()) {
-            final Sequence value = convertToDeliveryFormat(options, resultDocument.getValue());
-            outputMap.add(new AnyURIValue(resultDocument.getKey()), value);
+            final AnyURIValue key = new AnyURIValue(resultDocument.getKey());
+            final Sequence value = postProcess(key, convertToDeliveryFormat(options, resultDocument.getValue()), options.postProcess);
+            outputMap.add(key, value);
         }
 
         return outputMap;
@@ -537,16 +539,26 @@ private MapType makeResultMap(final Options options, final Sequence rawPrimaryOu
             outputKey = new StringValue("output");
         }
 
-        outputMap.add(outputKey, rawPrimaryOutput);
+        outputMap.add(outputKey, postProcess(outputKey, rawPrimaryOutput, options.postProcess));
 
         for (final Map.Entry<URI, Delivery> resultDocument : resultDocuments.entrySet()) {
-            final Sequence value = convertToDeliveryFormat(options, resultDocument.getValue());
-            outputMap.add(new AnyURIValue(resultDocument.getKey()), value);
+            final AnyURIValue key = new AnyURIValue(resultDocument.getKey());
+            final Sequence value = postProcess(key, convertToDeliveryFormat(options, resultDocument.getValue()), options.postProcess);
+            outputMap.add(key, value);
         }
 
         return outputMap;
     }
 
+    private Sequence postProcess(final AtomicValue key, final Sequence before, final Optional<FunctionReference> postProcessingFunction) throws XPathException {
+        if (postProcessingFunction.isPresent()) {
+            FunctionReference functionReference = postProcessingFunction.get();
+            return functionReference.evalFunction(null, null, new Sequence[]{key, before});
+        } else {
+            return before;
+        }
+    }
+
     private Sequence convertToDeliveryFormat(final Options options, final Delivery delivery) throws XPathException {
 
         switch (options.deliveryFormat) {
@@ -1041,6 +1053,8 @@ private Map<net.sf.saxon.s9api.QName, XdmValue> readParamsMap(final Optional<Map
         final Optional<Long> sourceTextChecksum;
         final String stylesheetNodeDocumentPath;
 
+        final Optional<FunctionReference> postProcess;
+
         Options(final MapType options) throws XPathException {
             xsltSource = getStylesheet(options);
 
@@ -1107,6 +1121,8 @@ private Map<net.sf.saxon.s9api.QName, XdmValue> readParamsMap(final Optional<Map
             serializationParams = FnTransform.SERIALIZATION_PARAMS.get(xsltVersion, options);
 
             validateRequestedProperties(FnTransform.REQUESTED_PROPERTIES.get(xsltVersion, options).orElse(new MapType(context)));
+
+            postProcess = FnTransform.POST_PROCESS.get(xsltVersion, options);
         }
 
         private DeliveryFormat getDeliveryFormat(final float xsltVersion, final MapType options) throws XPathException {

exist-core/src/test/java/xquery/xquery3/XQuery3Tests.java

@@ -27,7 +27,7 @@
 @RunWith(XSuite.class)
 @XSuite.XSuiteFiles({
         //"src/test/xquery/xquery3",
-        "src/test/xquery/xquery3/fnTransformErr9.xqm"
+        "src/test/xquery/xquery3/fnTransform79.xqm"
 })
 public class XQuery3Tests {
 }

exist-core/src/test/xquery/xquery3/fnTransform79.xqm

@@ -0,0 +1,46 @@
+(:
+ : eXist-db Open Source Native XML Database
+ : Copyright (C) 2001 The eXist-db Authors
+ :
+ : [email protected]
+ : http://www.exist-db.org
+ :
+ : This library is free software; you can redistribute it and/or
+ : modify it under the terms of the GNU Lesser General Public
+ : License as published by the Free Software Foundation; either
+ : version 2.1 of the License, or (at your option) any later version.
+ :
+ : This library is distributed in the hope that it will be useful,
+ : but WITHOUT ANY WARRANTY; without even the implied warranty of
+ : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ : Lesser General Public License for more details.
+ :
+ : You should have received a copy of the GNU Lesser General Public
+ : License along with this library; if not, write to the Free Software
+ : Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ :)
+xquery version "3.1";
+
+module namespace testTransform="http://exist-db.org/xquery/test/function_transform";
+
+declare namespace test="http://exist-db.org/xquery/xqsuite";
+
+declare variable $testTransform:transform-79-xsl :=
+"<xsl:stylesheet xmlns:xsl='http://www.w3.org/1999/XSL/Transform'
+                                                                 version='1.0'>
+                                                                 <xsl:template match='/'>
+                                                                   <out><xsl:copy-of select='.'/></out>
+                                                                 </xsl:template>
+                                                             </xsl:stylesheet>";
+
+declare
+    %test:assertEquals("<b>89</b>")
+function testTransform:transform-79() {
+    let $xsl := $testTransform:transform-79-xsl
+    let $trans-result := fn:transform(map{"stylesheet-text":$xsl,
+                                            "delivery-format" : "document",
+                                            "source-node": parse-xml('<a><b>89</b></a>'),
+                                            "post-process" : function($uri, $doc) { $doc/out/a/b }
+                                            })
+    return $trans-result("output")
+};