From 7e5a4f708c59affed216f9516bbcbcbca018b10f Mon Sep 17 00:00:00 2001
From: Sebastian Zarnekow <Sebastian.Zarnekow@itemis.de>
Date: Wed, 26 Oct 2011 13:24:30 +0200
Subject: [PATCH] [xbase] Enabled caching of unresolvable references to
 JvmTypes

This improves the performance vastly for resources with a lot of unknown type references (e.g. copy'n'paste code from a bugzilla without import statements)
---
 .../linking/lazy/LazyLinkingResource.java     | 30 ++++++++++++-------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/plugins/org.eclipse.xtext/src/org/eclipse/xtext/linking/lazy/LazyLinkingResource.java b/plugins/org.eclipse.xtext/src/org/eclipse/xtext/linking/lazy/LazyLinkingResource.java
index ee31f9cbb..75d6b8a63 100644
--- a/plugins/org.eclipse.xtext/src/org/eclipse/xtext/linking/lazy/LazyLinkingResource.java
+++ b/plugins/org.eclipse.xtext/src/org/eclipse/xtext/linking/lazy/LazyLinkingResource.java
@@ -14,6 +14,7 @@ import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 import org.apache.log4j.Logger;
 import org.eclipse.emf.common.util.TreeIterator;
@@ -41,6 +42,7 @@ import org.eclipse.xtext.util.Triple;
 
 import com.google.common.collect.Sets;
 import com.google.inject.Inject;
+import com.google.inject.Provider;
 
 /**
  * @author Sven Efftinge - Initial contribution and API
@@ -161,19 +163,20 @@ public class LazyLinkingResource extends XtextResource {
 				try {
 					if (!resolving.add(triple))
 						return handleCyclicResolution(triple);
-//					Set<String> unresolveableProxies = getCache().get("UNRESOLVEABLE_PROXIES", this,
-//							new Provider<Set<String>>() {
-//								public Set<String> get() {
-//									return Sets.newHashSet();
-//								}
-//							});
-//					if (unresolveableProxies.contains(uriFragment))
-//						return null;
+					Set<String> unresolveableProxies = getCache().get("UNRESOLVEABLE_PROXIES", this,
+							new Provider<Set<String>>() {
+								public Set<String> get() {
+									return Sets.newHashSet();
+								}
+							});
+					if (unresolveableProxies.contains(uriFragment))
+						return null;
 					EReference reference = triple.getSecond();
 					List<EObject> linkedObjects = getLinkingService().getLinkedObjects(triple.getFirst(), reference,
 							triple.getThird());
 					if (linkedObjects.isEmpty()) {
-//						unresolveableProxies.add(uriFragment);
+						if (isUnresolveableProxyCacheable(triple))
+							unresolveableProxies.add(uriFragment);
 						createAndAddDiagnostic(triple);
 						return null;
 					}
@@ -185,12 +188,13 @@ public class LazyLinkingResource extends XtextResource {
 						log.error("An element of type " + result.getClass().getName()
 								+ " is not assignable to the reference " + reference.getEContainingClass().getName()
 								+ "." + reference.getName());
-//						unresolveableProxies.add(uriFragment);
+						if (isUnresolveableProxyCacheable(triple))
+							unresolveableProxies.add(uriFragment);
 						createAndAddDiagnostic(triple);
 						return null;
 					}
 					// remove previously added error markers, since everything should be fine now
-//					unresolveableProxies.remove(uriFragment);
+					unresolveableProxies.remove(uriFragment);
 					removeDiagnostic(triple);
 					return result;
 				} finally {
@@ -207,6 +211,10 @@ public class LazyLinkingResource extends XtextResource {
 		return super.getEObject(uriFragment);
 	}
 
+	protected boolean isUnresolveableProxyCacheable(Triple<EObject, EReference, INode> triple) {
+		return true;
+	}
+
 	protected EObject handleCyclicResolution(Triple<EObject, EReference, INode> triple) throws AssertionError {
 		throw new AssertionError("Cyclic resolution of lazy links : " + getReferences(triple, resolving));
 	}