WstxEventFactory: Ensure events' immutable non-null location (#205)

release-notes/CREDITS

@@ -104,3 +104,8 @@ Alexey Gavrilov (@agavrilov76)
 Jeremy Norris (@norrisjeremy)
 * Reported #200: Fix shading of `isorelax` dependency (and other msv-core components)
  (6.6.2)
+
+Stanimir Stamenkov (@stanio)
+
+* Reported, provided fix for #204: Non-conformant `XMLEventFactory.setLocation(null)`
+ (7.0.0)

release-notes/VERSION

@@ -6,7 +6,8 @@ Project: woodstox
 
 6.7.0 (not yet released)
 
--
+#204: Non-conformant `XMLEventFactory.setLocation(null)`
+ (fix provided by Stanimir S)
 
 6.6.2 (26-Mar-2024)
 

src/main/java/com/ctc/wstx/stax/WstxEventFactory.java

@@ -23,10 +23,12 @@
 import javax.xml.stream.events.*;
 
 import aQute.bnd.annotation.spi.ServiceProvider;
+import org.codehaus.stax2.XMLStreamLocation2;
 import org.codehaus.stax2.ri.Stax2EventFactoryImpl;
 
 import com.ctc.wstx.compat.QNameCreator;
 import com.ctc.wstx.evt.*;
+import com.ctc.wstx.io.WstxInputLocation;
 
 /**
  * Implementation of {@link XMLEventFactory} to be used with
@@ -38,6 +40,7 @@ public final class WstxEventFactory
 {
     public WstxEventFactory() {
         super();
+        super.setLocation(WstxInputLocation.getEmptyLocation());
     }
 
     /*
@@ -46,6 +49,28 @@ public WstxEventFactory() {
     /////////////////////////////////////////////////////////////
      */
 
+    @Override
+    public void setLocation(Location location) {
+        super.setLocation(location == null ? WstxInputLocation.getEmptyLocation()
+                : immutableLocation(location));
+    }
+
+    private static WstxInputLocation immutableLocation(Location location) {
+        if (location == null) {
+            return null;
+        }
+        if (location.getClass() == WstxInputLocation.class) {
+            return (WstxInputLocation) location;
+        }
+
+        WstxInputLocation context = (location instanceof XMLStreamLocation2)
+                ? immutableLocation(((XMLStreamLocation2) location).getContext())
+                : null;
+        return new WstxInputLocation(context, location.getPublicId(),
+                location.getSystemId(), location.getCharacterOffset(),
+                location.getLineNumber(), location.getColumnNumber());
+    }
+
     //public Attribute createAttribute(QName name, String value)
     //public Attribute createAttribute(String localName, String value)
     //public Attribute createAttribute(String prefix, String nsURI, String localName, String value)

src/test/java/wstxtest/evt/TestEventFactoryLocation.java

@@ -0,0 +1,98 @@
+package wstxtest.evt;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+
+import java.util.Objects;
+
+import javax.xml.stream.Location;
+import javax.xml.stream.events.XMLEvent;
+
+import org.hamcrest.Description;
+import org.hamcrest.Matcher;
+import org.hamcrest.TypeSafeMatcher;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.ctc.wstx.io.WstxInputLocation;
+import com.ctc.wstx.stax.WstxEventFactory;
+
+public class TestEventFactoryLocation {
+
+    private WstxEventFactory eventFactory;
+
+    @Before
+    public void setUp() {
+        eventFactory = new WstxEventFactory();
+    }
+
+    @Test
+    public void testDefaultLocation() {
+        XMLEvent event = eventFactory.createStartDocument();
+
+        assertThat("event.location", event.getLocation(), unknownLocation());
+    }
+
+    @Test
+    public void testResetLocation() {
+        eventFactory.setLocation(new WstxInputLocation(null, null, "about:blank", 3L, 2, 1));
+        eventFactory.setLocation(null);
+
+        XMLEvent event = eventFactory.createStartElement("foo", "bar", "baz");
+
+        assertThat("event.location", event.getLocation(), unknownLocation());
+    }
+
+    @Test
+    public void testNonVolatileLocation() {
+        VolatileLocation volatileLocation = new VolatileLocation(2, 3);
+        eventFactory.setLocation(volatileLocation);
+
+        XMLEvent event = eventFactory.createEndElement("foo", "bar", "baz");
+        volatileLocation.line = 4;
+        volatileLocation.col = 5;
+
+        assertThat("event.location", event.getLocation(),
+                locationWithProperties(null, null, -1, 2, 3));
+    }
+
+    private static Matcher<Location> unknownLocation() {
+        // XXX: Not sure if the empty-string publicId/systemId are conformant
+        //return locationWithProperties(null, null, -1, -1, -1);
+        return locationWithProperties("", "", -1, -1, -1);
+    }
+
+    private static Matcher<Location> locationWithProperties(final String pubId,
+            final String sysId, final int charOffset, final int row, final int col) {
+        return new TypeSafeMatcher<Location>() {
+            @Override public void describeTo(Description description) {
+                description.appendText("Location(publicId: ").appendValue(pubId)
+                           .appendText(", systemId: ").appendValue(sysId)
+                           .appendText(", characterOffset: ").appendValue(charOffset)
+                           .appendText(", lineNumber: ").appendValue(row)
+                           .appendText(", columnNumber: ").appendValue(col);
+            }
+
+            @Override protected boolean matchesSafely(Location item) {
+                return Objects.equals(item.getPublicId(), pubId)
+                        && Objects.equals(item.getSystemId(), sysId)
+                        && Objects.equals(item.getCharacterOffset(), charOffset)
+                        && Objects.equals(item.getLineNumber(), row)
+                        && Objects.equals(item.getColumnNumber(), col);
+            }
+        };
+    }
+
+    static class VolatileLocation implements Location {
+        int line;
+        int col;
+        VolatileLocation(int line, int col) {
+            this.line = line;
+            this.col = col;
+        }
+        @Override public String getPublicId() { return null; }
+        @Override public String getSystemId() { return null; }
+        @Override public int getLineNumber() { return line; }
+        @Override public int getColumnNumber() { return col; }
+        @Override public int getCharacterOffset() { return -1; }
+    }
+}