Fix: https://bugs.eclipse.org/bugs/show_bug.cgi?id=269680

2 files changed, 48 insertions, 8 deletions

diff --git a/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/contentassist/impl/DefaultContentAssistContextFactory.java b/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/contentassist/impl/DefaultContentAssistContextFactory.java
index 298e1ab..b7b9dd9 100755
--- a/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/contentassist/impl/DefaultContentAssistContextFactory.java
+++ b/plugins/org.eclipse.xtext.ui.common/src/org/eclipse/xtext/ui/common/editor/contentassist/impl/DefaultContentAssistContextFactory.java
@@ -17,7 +17,9 @@ import org.eclipse.jface.text.ITextSelection;
 import org.eclipse.jface.text.ITextViewer;
 import org.eclipse.jface.text.Region;
 import org.eclipse.xtext.CrossReference;
+import org.eclipse.xtext.GrammarUtil;
 import org.eclipse.xtext.Keyword;
+import org.eclipse.xtext.ParserRule;
 import org.eclipse.xtext.RuleCall;
 import org.eclipse.xtext.TerminalRule;
 import org.eclipse.xtext.parser.IParseResult;
@@ -62,9 +64,10 @@ public class DefaultContentAssistContextFactory implements ContentAssistContext.
 		
 		CompositeNode rootNode = parseResult.getRootNode();
 		AbstractNode lastCompleteNode = ParseTreeUtil.getLastCompleteNodeByOffset(rootNode, fixedOffset);
+		lastCompleteNode = getContainingDatatypeRuleNode(lastCompleteNode);
 		EObject currentModel = NodeUtil.getNearestSemanticObject(lastCompleteNode);
 		AbstractNode currentNode = ParseTreeUtil.getCurrentOrFollowingNodeByOffset(rootNode, fixedOffset);
-		
+		currentNode = getContainingDatatypeRuleNode(currentNode);
 		if (lastCompleteNode.getOffset()+lastCompleteNode.getLength() == fixedOffset) {
 			AbstractNode precedingLastCompleteNode = ParseTreeUtil.getLastCompleteNodeByOffset(rootNode, Math.max(0, lastCompleteNode.getOffset()));
 			String prefix = getPrefix(lastCompleteNode, fixedOffset);
@@ -88,6 +91,20 @@ public class DefaultContentAssistContextFactory implements ContentAssistContext.
 		return result.toArray(new ContentAssistContext[result.size()]);
 	}
 
+	public AbstractNode getContainingDatatypeRuleNode(AbstractNode node) {
+		AbstractNode result = node;
+		EObject grammarElement = result.getGrammarElement();
+		if (grammarElement != null) {
+			ParserRule parserRule = GrammarUtil.containingParserRule(grammarElement);
+			while(parserRule != null && GrammarUtil.isDatatypeRule(parserRule)) {
+				result = result.getParent();
+				grammarElement = result.getGrammarElement();
+				parserRule = GrammarUtil.containingParserRule(grammarElement);
+			}
+		}
+		return result;
+	}
+
 	public ContentAssistContext createContext(ITextViewer viewer, int offset, IParseResult parseResult, CompositeNode rootNode,
 			AbstractNode lastCompleteNode, EObject currentModel, AbstractNode currentNode, String prefix) {
 		ITextSelection selection= (ITextSelection) viewer.getSelectionProvider().getSelection();
@@ -113,21 +130,22 @@ public class DefaultContentAssistContextFactory implements ContentAssistContext.
 		return context;
 	}
 	
-	public String getPrefix(AbstractNode currentNode, int offset) {
-		if (currentNode instanceof LeafNode) {
-			if (((LeafNode) currentNode).isHidden())
+	public String getPrefix(AbstractNode prefixNode, int offset) {
+		if (prefixNode instanceof LeafNode) {
+			if (((LeafNode) prefixNode).isHidden())
 				return "";
-			return getNodeText(currentNode, offset);
+			return getNodeText(prefixNode, offset);
 		}
-		StringBuilder result = new StringBuilder(currentNode.getTotalLength());
-		doComputePrefix((CompositeNode) currentNode, result, offset);
+		StringBuilder result = new StringBuilder(prefixNode.getTotalLength());
+		doComputePrefix((CompositeNode) prefixNode, result, offset);
 		return result.toString();
 	}
 
 	public String getNodeText(AbstractNode currentNode, int offset) {
 		int startOffset = currentNode.getOffset();
 		String text = ((LeafNode) currentNode).getText();
-		String result = text.substring(0, offset - startOffset);
+		int length = offset - startOffset;
+		String result = length > text.length() ? text : text.substring(0, length);
 		return result;
 	}
 	
diff --git a/tests/org.eclipse.xtext.ui.common.tests/src/org/eclipse/xtext/ui/common/editor/contentassist/impl/AbstractContentAssistProcessorTest.java b/tests/org.eclipse.xtext.ui.common.tests/src/org/eclipse/xtext/ui/common/editor/contentassist/impl/AbstractContentAssistProcessorTest.java
index 83beeb7..0c2cc4d 100755
--- a/tests/org.eclipse.xtext.ui.common.tests/src/org/eclipse/xtext/ui/common/editor/contentassist/impl/AbstractContentAssistProcessorTest.java
+++ b/tests/org.eclipse.xtext.ui.common.tests/src/org/eclipse/xtext/ui/common/editor/contentassist/impl/AbstractContentAssistProcessorTest.java
@@ -291,6 +291,28 @@ public abstract class AbstractContentAssistProcessorTest extends AbstractXtextTe
         .appendNl("Rule: name=ID;")

         .assertTextAtCursorPosition("generate", 3,"generate");

     }

+    

+    /**

+     * https://bugs.eclipse.org/bugs/show_bug.cgi?id=269680

+     */

+    public void testCompletionOnDatatypeReference_01() throws Exception {

+        newBuilder(setup.getXtextSetup())

+	        .appendNl("grammar foo with org.eclipse.xtext.common.Terminals")

+	        .appendNl("generate meta \"url\"")

+	        .appendNl("Rule: name=ID;")

+	        .assertTextAtCursorPosition("org.eclipse.xtext", 2, "org.eclipse.xtext.common.Terminals");

+    }

+    

+    /**

+     * https://bugs.eclipse.org/bugs/show_bug.cgi?id=269680

+     */

+    public void testCompletionOnDatatypeReference_02() throws Exception {

+        newBuilder(setup.getXtextSetup())

+	        .appendNl("grammar foo with org.eclipse.xtext.common.Terminals")

+	        .appendNl("generate meta \"url\"")

+	        .appendNl("Rule: name=ID;")

+	        .assertTextAtCursorPosition("org.eclipse.xtext", 5, "org.eclipse.xtext.common.Terminals");

+    }

 

     /**

      * regression test for: