Bug 471103 Add caching for performance improvements of indexing process

Change-Id: I56d3dea7e159f99fad083c6965a409c26b8de747
Signed-off-by: Karsten Thoms <karsten.thoms@itemis.de>

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/dom/PDOMProjectIndexLocationConverter.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2006, 2008 Symbian Software Ltd. and others.
+ * Copyright (c) 2006, 2015 Symbian Software Ltd. and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -8,11 +8,14 @@
  * Contributors:
  *     Andrew Ferguson (Symbian) - initial API and implementation
  *     Markus Schorn (Wind River Systems)
+ *     Karsten Thoms (itemis) - Bug 471103
  *******************************************************************************/
  package org.eclipse.cdt.internal.core.pdom.dom;
 
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.util.HashMap;
+import java.util.Map;
 
 import org.eclipse.cdt.core.index.IIndexFileLocation;
 import org.eclipse.cdt.core.index.IIndexLocationConverter;
@@ -33,6 +36,8 @@ public class PDOMProjectIndexLocationConverter implements IIndexLocationConverte
 	final private IWorkspaceRoot fRoot;
 	final private String fFullPathPrefix;
 	final private boolean fIgnoreExternal;
+	// Cache for results of method fromInternalFormat (bug 471103).
+	final Map<String, IIndexFileLocation> fromInternalFormatCache = new HashMap<>();
 
 	public PDOMProjectIndexLocationConverter(IProject project) {
 		this(project, false);
@@ -46,6 +51,12 @@ public class PDOMProjectIndexLocationConverter implements IIndexLocationConverte
 
 	@Override
 	public IIndexFileLocation fromInternalFormat(String raw) {
+		// Fast return when 'raw' was queried before (bug 471103).
+		IIndexFileLocation cachedResult = fromInternalFormatCache.get(raw);
+		if (cachedResult != null) {
+			return cachedResult;
+		}
+
 		String fullPath = null;
 		URI uri= null;
 		if (raw.startsWith(EXTERNAL)) {
@@ -65,7 +76,12 @@ public class PDOMProjectIndexLocationConverter implements IIndexLocationConverte
 				uri = member.getLocationURI();
 			}
 		}
-		return uri == null ? null : new IndexFileLocation(uri, fullPath);
+		if (uri == null)
+			return null;
+
+		IndexFileLocation location = new IndexFileLocation(uri, fullPath);
+		fromInternalFormatCache.put(raw, location);
+		return location;
 	}
 
 	@Override

core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/indexer/FileExistsCache.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2008, 2011 Wind River Systems, Inc. and others.
+ * Copyright (c) 2008, 2015 Wind River Systems, Inc. and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -7,6 +7,7 @@
  *
  * Contributors:
  *     Markus Schorn - initial API and implementation
+ *     Karsten Thoms (itemis) - Bug 471103
  *******************************************************************************/
 package org.eclipse.cdt.internal.core.pdom.indexer;
 
@@ -44,6 +45,8 @@ public final class FileExistsCache {
 	}
 
 	private Reference<Map<String, Content>> fCache;
+	// Cache for recent results of isFile calls (bug 471103).
+	private final Map<String, Boolean> fCacheIsFile = new HashMap<>();
 	private final boolean fCaseInSensitive;
 
 	public FileExistsCache(boolean caseInsensitive) {
@@ -54,6 +57,19 @@ public final class FileExistsCache {
 	}
 
 	public boolean isFile(String path) {
+		// Fast return when path was already queried. The method is potentially called multiple times with
+		// the same path on each return statement the returned value is stored in the cache (bug 471103).
+		Boolean cachedResult = fCacheIsFile.get(path);
+		if (!BYPASS_CACHE && cachedResult != null) {
+			return cachedResult.booleanValue();
+		}
+
+		boolean result = isFileInternal(path);
+		fCacheIsFile.put(path, result);
+		return result;
+	}
+
+	private boolean isFileInternal(String path) {
 		String parent;
 		String name;
 		File file = null;