[storage] allow nullable URIs. E.g. ReferenceDescription containerEObjectURI might be null if the reference is in a root eobject.

Change-Id: I25a354ca8d05a97c24be34c65170167f37f5128e

plugins/org.eclipse.xtext/src/org/eclipse/xtext/resource/persistence/PortableURIs.xtend

@@ -21,7 +21,7 @@ import org.eclipse.emf.ecore.util.EcoreUtil
 import org.eclipse.xtend.lib.annotations.Data
 import org.eclipse.xtext.naming.QualifiedName
 import org.eclipse.xtext.resource.IEObjectDescription
-import org.eclipse.xtext.resource.IResourceServiceProvider
+import org.eclipse.xtext.resource.impl.ResourceDescriptionsProvider
 import org.eclipse.xtext.scoping.IGlobalScopeProvider
 
 /**
@@ -45,9 +45,8 @@ class PortableURIs {
 	public static val PORTABLE_SCHEME = "portable"
 	
 	@Inject IGlobalScopeProvider globalScopeProvider
-//	@Inject LazyURIEncoder lazyURIencoder
 	@Inject EPackage.Registry packageRegistry
-	@Inject IResourceServiceProvider.Registry resourceServiceProviderRegistry
+	@Inject ResourceDescriptionsProvider resourceDescriptionsProvider
 	
 	/**
 	 * @return whether the given string is a portable URI fragment
@@ -89,9 +88,12 @@ class PortableURIs {
 	 */
 	def URI toPortableURI(StorageAwareResource sourceResource, URI targetURI) {
 		val to = sourceResource.resourceSet.getResource(targetURI.trimFragment, false)?.getEObject(targetURI.fragment)
-		val result = toPortableURI(sourceResource, to);
-		if (result != null) {
-			return result
+		// if it points to some registered ecore, there's no resourceSet and the result is not portable 
+		if (to == null || to.eResource.resourceSet != null) {
+			val result = toPortableURI(sourceResource, to);
+			if (result != null) {
+				return result
+			}
 		}
 		return null
 	}
@@ -121,8 +123,8 @@ class PortableURIs {
 	 * @return a portable URI fragment, or <code>null</code> if the give EObject isn't itself or is not contained in an exported EObjectDescription
 	 */
 	protected def String getPortableURIFragment(EObject obj) {
-		val serviceProvider = resourceServiceProviderRegistry.getResourceServiceProvider(EcoreUtil.getURI(obj))
-		val desc = serviceProvider?.resourceDescriptionManager?.getResourceDescription(obj.eResource)
+		val descriptions = resourceDescriptionsProvider.getResourceDescriptions(obj.eResource)
+		val desc = descriptions.getResourceDescription(obj.eResource.URI)
 		if (desc == null) {
 			return null
 		}

plugins/org.eclipse.xtext/src/org/eclipse/xtext/resource/persistence/SerializableResourceDescription.xtend

@@ -242,11 +242,19 @@ package class SerializationExtensions {
 	}
 	
 	def static URI readURI(ObjectInput in) {
-		return URI::createURI(in.readUTF)
+		val stringRep = in.readUTF
+		if (stringRep == "NULL") {
+			return null
+		}
+		return URI::createURI(stringRep)
 	}
 	
 	def static void writeURI(ObjectOutput out, URI uri) {
-		out.writeUTF(uri.toString)
+		if (uri == null) {
+			out.writeUTF("NULL")
+		} else {
+			out.writeUTF(uri.toString)
+		}
 	}
 	
 	def static QualifiedName readQualifiedName(ObjectInput in) {

tests/org.eclipse.xtext.tests/src/org/eclipse/xtext/resource/persistence/SerializableResourceDescriptionTest.xtend

@@ -62,6 +62,11 @@ class SerializableResourceDescriptionTest {
 		objectOut.writeObject(before)
 		val in = new ObjectInputStream(new ByteArrayInputStream(bout.toByteArray)) 
 		val after = in.readObject as SerializableResourceDescription
+		
+		assertDescriptionsEqual(before, after)
+	}
+	
+	def void assertDescriptionsEqual(SerializableResourceDescription before, SerializableResourceDescription after) {
 		assertEquals(before.URI, after.URI)
 		assertEquals(before.importedNames, after.importedNames)
 
@@ -86,4 +91,64 @@ class SerializableResourceDescriptionTest {
 			assertEquals(beforeDesc.EObjectURI, afterDesc.EObjectURI)
 		}
 	}
+	
+	@Test def void testNullSafeSerialization() {
+		val uri = URI::createURI("file:/foo/bar.baz.foo")
+		val before = new SerializableResourceDescription => [
+			URI = uri 
+			references = #[
+				new SerializableReferenceDescription => [
+					sourceEObjectUri = uri.appendFragment('foo')
+					targetEObjectUri = null
+					containerEObjectURI = uri.appendFragment('baz')
+					EReference = EcorePackage.eINSTANCE.EAnnotation_Contents
+					indexInList = 1
+				],
+				new SerializableReferenceDescription => [
+					sourceEObjectUri = null
+					targetEObjectUri = uri.appendFragment('hubble2')
+					containerEObjectURI = uri.appendFragment('baz2')
+					EReference = EcorePackage.eINSTANCE.EAnnotation_Contents
+					indexInList = 2
+				],
+				new SerializableReferenceDescription => [
+					sourceEObjectUri = uri.appendFragment('foo')
+					targetEObjectUri = uri.appendFragment('hubble2')
+					containerEObjectURI = null
+					EReference = EcorePackage.eINSTANCE.EAnnotation_Contents
+					indexInList = 2
+				],
+				new SerializableReferenceDescription => [
+					sourceEObjectUri = uri.appendFragment('foo')
+					targetEObjectUri = null
+					containerEObjectURI = null
+					EReference = EcorePackage.eINSTANCE.EAnnotation_Contents
+					indexInList = 2
+				],
+				new SerializableReferenceDescription => [
+					sourceEObjectUri = null
+					targetEObjectUri = null
+					containerEObjectURI = null
+					EReference = EcorePackage.eINSTANCE.EAnnotation_Contents
+					indexInList = 2
+				]
+			]
+			descriptions = #[
+				new SerializableEObjectDescription => [
+					EObjectURI = uri.appendFragment('baz')
+					qualifiedName = QualifiedName.create('foo','baz')
+					EClass = EcorePackage.eINSTANCE.EAttribute
+					userData = newHashMap('myKey' -> 'myValue')
+				]
+			]
+			importedNames = #[QualifiedName.create('foo'), QualifiedName.create('foo','bar')]
+		]
+		
+		val bout = new ByteArrayOutputStream()
+		val objectOut = new ObjectOutputStream(bout)
+		objectOut.writeObject(before)
+		val in = new ObjectInputStream(new ByteArrayInputStream(bout.toByteArray)) 
+		val after = in.readObject as SerializableResourceDescription
+		assertDescriptionsEqual(before, after)
+	}
 }