basic redefine support

based on goetas-webservices#17
by @kstasik

ported code to latest version/rebased on master.

implements `<xsd:redefine ...>` https://www.w3.org/TR/xmlschema11-1/#modify-schema

Author: Kacper Stasik

src/SchemaReader.php

@@ -254,6 +254,9 @@ function (
                     case 'import':
                         $callback = $this->loadImport($schema, $childNode);
                         break;
+                    case 'redefine':
+                        $callback = $this->loadRedefine($schema, $childNode);
+                        break;
                     case 'element':
                         $callback = $this->loadElementDef($schema, $childNode);
                         break;
@@ -1144,6 +1147,28 @@ private function loadImport(
         return $this->loadImportFresh($namespace, $schema, $file);
     }
 
+    private function loadRedefine(Schema $schema, DOMElement $node)
+    {
+        $base = urldecode($node->ownerDocument->documentURI);
+        $file = UrlUtils::resolveRelativeUrl($base, $node->getAttribute('schemaLocation'));
+
+        if (isset($this->loadedFiles[$file])) {
+            /* @var $redefined Schema */
+            $redefined = clone $this->loadedFiles[$file];
+
+            if($schema->getTargetNamespace() !== $redefined->getTargetNamespace()){
+                $redefined->setTargetNamespace($schema->getTargetNamespace());
+            }
+
+            $schema->addSchema($redefined);
+
+            return function (): void {
+            };
+        }
+
+        return $this->loadImportFresh($schema->getTargetNamespace(), $schema, $file);
+    }
+
     private function createOrUseSchemaForNs(
         Schema $schema,
         string $namespace

tests/RedefineTest.php

@@ -0,0 +1,66 @@
+<?php
+namespace GoetasWebservices\XML\XSDReader\Tests;
+
+class RedefineTest extends BaseTest
+{
+    public function testBase()
+    {
+        $remoteSchema = $this->reader->readString(
+            '
+            <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">
+                <xs:complexType name="personName">
+                  <xs:sequence>
+                   <xs:element name="title" minOccurs="0"/>
+                   <xs:element name="forename" minOccurs="0" maxOccurs="unbounded"/>
+                  </xs:sequence>
+                 </xs:complexType>
+
+                <xs:element name="addressee" type="personName"/>
+            </xs:schema>', 'http://www.example.com/xsd.xsd');
+
+
+        $schema = $this->reader->readString(
+            '
+            <xs:schema targetNamespace="http://www.user.com" xmlns:xs="http://www.w3.org/2001/XMLSchema"  xmlns:ex="http://www.example.com">
+                <xs:redefine schemaLocation="http://www.example.com/xsd.xsd">
+                  <xs:complexType name="personName">
+                   <xs:complexContent>
+                    <xs:extension base="personName">
+                     <xs:sequence>
+                      <xs:element name="generation" minOccurs="0"/>
+                     </xs:sequence>
+                    </xs:extension>
+                   </xs:complexContent>
+                  </xs:complexType>
+                 </xs:redefine>
+
+                 <xs:element name="author" type="personName"/>
+            </xs:schema>');
+
+        // check if schema is not included
+        // we don't want to redefine original schema
+        $this->assertNotContains($remoteSchema, $schema->getSchemas(), '', true);
+
+        /* @var $localAttr \GoetasWebservices\XML\XSDReader\Schema\Element\ElementDef */
+
+        // it should inherit namespace of main schema
+        $localAttr = $schema->findElement("addressee", "http://www.user.com");
+        $this->assertNotNull($localAttr);
+
+        // find author element
+        $localAttr = $schema->findElement("author", "http://www.user.com");
+        $this->assertNotNull($localAttr);
+
+        /* @var $type \GoetasWebservices\XML\XSDReader\Schema\Type\ComplexType */
+        $type = $localAttr->getType();
+
+        $this->assertInstanceOf('\GoetasWebservices\XML\XSDReader\Schema\Type\ComplexType', $type);
+
+        $children = array();
+        foreach($type->getElements() as $element){
+            $children[] = $element->getName();
+        }
+
+        $this->assertContains('generation', $children);
+    }
+}