From 66b8ace522199fc77d70f8b97162c6e1c82c687b Mon Sep 17 00:00:00 2001
From: Moritz Eysholdt <moritz.eysholdt@typefox.io>
Date: Fri, 14 Oct 2016 09:07:32 +0200
Subject: [PATCH] [GrammarUtil/perf] make containing*() fast for misses

containingAssignment() and containingCrossReference() should return
null as fast as possible when there is no Assignemnt/CrossReference

Signed-off-by: Moritz Eysholdt <moritz.eysholdt@typefox.io>
---
 .../src/org/eclipse/xtext/GrammarUtil.java    | 39 ++++++++++++++++++-
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/org.eclipse.xtext/src/org/eclipse/xtext/GrammarUtil.java b/org.eclipse.xtext/src/org/eclipse/xtext/GrammarUtil.java
index 3f08d2f5b..66d405bcc 100644
--- a/org.eclipse.xtext/src/org/eclipse/xtext/GrammarUtil.java
+++ b/org.eclipse.xtext/src/org/eclipse/xtext/GrammarUtil.java
@@ -120,7 +120,26 @@ public class GrammarUtil {
 	}
 
 	public static Assignment containingAssignment(EObject e) {
-		return getContainerOfType(e, Assignment.class);
+		EObject current = e;
+		while (current != null) {
+			switch (current.eClass().getClassifierID()) {
+			case XtextPackage.ASSIGNMENT:
+				return (Assignment) current;
+			case XtextPackage.GROUP:
+			case XtextPackage.UNORDERED_GROUP:
+			case XtextPackage.PARSER_RULE:
+			case XtextPackage.TERMINAL_RULE:
+			case XtextPackage.ENUM_RULE:
+				return null;
+			case XtextPackage.ALTERNATIVES:
+				if (((Alternatives) current).getCardinality() != null) {
+					return null;
+				}
+			default:
+				current = current.eContainer();
+			}
+		}
+		return null;
 	}
 
 	public static Group containingGroup(EObject e) {
@@ -132,7 +151,23 @@ public class GrammarUtil {
 	}
 
 	public static CrossReference containingCrossReference(EObject e) {
-		return getContainerOfType(e, CrossReference.class);
+		EObject current = e;
+		while (current != null) {
+			switch (current.eClass().getClassifierID()) {
+			case XtextPackage.CROSS_REFERENCE:
+				return (CrossReference) current;
+			case XtextPackage.GROUP:
+			case XtextPackage.UNORDERED_GROUP:
+			case XtextPackage.ALTERNATIVES:
+			case XtextPackage.PARSER_RULE:
+			case XtextPackage.TERMINAL_RULE:
+			case XtextPackage.ENUM_RULE:
+				return null;
+			default:
+				current = current.eContainer();
+			}
+		}
+		return null;
 	}
 
 	public static List<Action> containedActions(EObject e) {