Bug 512251 - Fix IllegalArgumentException in ContextInformationPopupI20171011-2000I20171011-0305I20171010-2000I20171009-2000I20171008-2000I20171007-1500I20171006-2000I20171005-2000I20171004-2000I20171004-0315I20171003-2000I20171002-2000

Change-Id: I7c6eec0871e7f2b3a2a71c401b19e52a687f126e
Signed-off-by: Stephan Wahlbrink <sw@wahlbrink.eu>

2 files changed, 38 insertions, 8 deletions

diff --git a/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/ContentAssistSubjectControlAdapter.java b/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/ContentAssistSubjectControlAdapter.java
index 8d648d91b84..af6d754196e 100644
--- a/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/ContentAssistSubjectControlAdapter.java
+++ b/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/ContentAssistSubjectControlAdapter.java
@@ -8,6 +8,7 @@
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *     Mickael Istria (Red Hat Inc.) - [251156] Allow multiple contentAssitProviders internally & inheritance
+ *     Stephan Wahlbrink <sw@wahlbrink.eu> - Bug 512251 - Fix IllegalArgumentException in ContextInformationPopup
  *******************************************************************************/
 package org.eclipse.jface.text.contentassist;
 
@@ -120,6 +121,14 @@ class ContentAssistSubjectControlAdapter implements IContentAssistSubjectControl
 		return fViewer.getTextWidget().getLineDelimiter();
 	}
 
+	public boolean isValidWidgetOffset(int widgetOffset) {
+		if (fContentAssistSubjectControl != null) {
+			IDocument document= fContentAssistSubjectControl.getDocument();
+			return (widgetOffset >= 0 && widgetOffset <= document.getLength());
+		}
+		return (widgetOffset >= 0 && widgetOffset <= fViewer.getTextWidget().getCharCount());
+	}
+
 	@Override
 	public void addKeyListener(KeyListener keyListener) {
 		if (fContentAssistSubjectControl != null)
diff --git a/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/ContextInformationPopup.java b/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/ContextInformationPopup.java
index f733d6dad4c..8315265a97f 100644
--- a/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/ContextInformationPopup.java
+++ b/org.eclipse.jface.text/src/org/eclipse/jface/text/contentassist/ContextInformationPopup.java
@@ -7,6 +7,7 @@
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
+ *     Stephan Wahlbrink <sw@wahlbrink.eu> - Bug 512251 - Fix IllegalArgumentException in ContextInformationPopup
  *******************************************************************************/
 package org.eclipse.jface.text.contentassist;
 
@@ -274,7 +275,7 @@ class ContextInformationPopup implements IContentAssistListener {
 	 * @since 3.0
 	 */
 	private void internalShowContextInfo(ContextFrame frame) {
-		if (frame != null) {
+		if (frame != null && canShowFrame(frame)) {
 			fContextFrameStack.push(frame);
 			if (fContextFrameStack.size() == 1)
 				fLastContext= null;
@@ -336,6 +337,19 @@ class ContextInformationPopup implements IContentAssistListener {
 	}
 
 	/**
+	 * Pre-checks if the given context frame can be (re)shown.
+	 *
+	 * The function checks if the frame has valid position data. It does not call the context
+	 * information validator.
+	 *
+	 * @param frame the frame to check
+	 * @return <code>true</code> if the context frame OK to use, otherwise <code>false</code>
+	 */
+	private boolean canShowFrame(ContextFrame frame) {
+		return fContentAssistSubjectControlAdapter.isValidWidgetOffset(frame.fVisibleOffset);
+	}
+
+	/**
 	 * Shows the given context frame.
 	 *
 	 * @param frame the frame to display
@@ -457,16 +471,23 @@ class ContextInformationPopup implements IContentAssistListener {
 		if (Helper.okToUse(fContextInfoPopup)) {
 
 			int size= fContextFrameStack.size();
-			if (size > 0) {
+			while (size > 0) {
 				fLastContext= fContextFrameStack.pop();
 				-- size;
-			}
-
-			if (size > 0) {
-				ContextFrame current= fContextFrameStack.peek();
-				internalShowContextFrame(current, false);
-			} else {
 
+				if (size > 0) {
+					ContextFrame current= fContextFrameStack.peek();
+					if (canShowFrame(current)) {
+						internalShowContextFrame(current, false);
+						return;
+					}
+					// continue - try next
+				}
+				else {
+					break;
+				}
+			}
+			{
 				fContentAssistant.removeContentAssistListener(this, ContentAssistant.CONTEXT_INFO_POPUP);
 
 				if (fContentAssistSubjectControlAdapter.getControl() != null)