Bug 515504 - rebuildIndexshould erase the new index db if it is disabledI20170426-2000

This reverts commit ff9698f664fadd62325b86c1541d7575aabf84c8.

Change-Id: I020091c5f004e5b82335d26f521146a2ed01deb2

2 files changed, 12 insertions, 5 deletions

diff --git a/org.eclipse.jdt.core/model/org/eclipse/jdt/core/JavaCore.java b/org.eclipse.jdt.core/model/org/eclipse/jdt/core/JavaCore.java
index ffb80ea513..ad45148cc1 100644
--- a/org.eclipse.jdt.core/model/org/eclipse/jdt/core/JavaCore.java
+++ b/org.eclipse.jdt.core/model/org/eclipse/jdt/core/JavaCore.java
@@ -5517,7 +5517,8 @@ public final class JavaCore extends Plugin {
 	}
 
 	/**
-	 * Deletes and rebuilds the java index.
+	 * Deletes the index, then rebuilds any portions of the index that are
+	 * currently needed by the workspace.
 	 * 
 	 * @param monitor a progress monitor, or <code>null</code> if progress
 	 *    reporting and cancellation are not desired
diff --git a/org.eclipse.jdt.core/search/org/eclipse/jdt/internal/core/nd/indexer/Indexer.java b/org.eclipse.jdt.core/search/org/eclipse/jdt/internal/core/nd/indexer/Indexer.java
index b149447f92..5922a94ffe 100644
--- a/org.eclipse.jdt.core/search/org/eclipse/jdt/internal/core/nd/indexer/Indexer.java
+++ b/org.eclipse.jdt.core/search/org/eclipse/jdt/internal/core/nd/indexer/Indexer.java
@@ -1046,18 +1046,24 @@ public final class Indexer {
 	}
 
 	public void rebuildIndex(IProgressMonitor monitor) throws CoreException {
-		if (!JavaIndex.isEnabled()) {
-			return;
-		}
 		SubMonitor subMonitor = SubMonitor.convert(monitor, 100);
 
+		this.rescanJob.cancel();
+		try {
+			this.rescanJob.join(0, subMonitor.split(1));
+		} catch (InterruptedException e) {
+			// Nothing to do.
+		}
 		this.nd.acquireWriteLock(subMonitor.split(1));
 		try {
 			this.nd.clear(subMonitor.split(2));
 		} finally {
 			this.nd.releaseWriteLock();
 		}
-		rescan(subMonitor.split(98));
+		if (!JavaIndex.isEnabled()) {
+			return;
+		}
+		rescan(subMonitor.split(97));
 	}
 
 	public void requestRebuildIndex() {