Version 1.7.0-dev.3.3

editor/tools/plugins/com.google.dart.engine/src/com/google/dart/engine/sdk/DirectoryBasedDartSdk.java

 /*
  * Copyright (c) 2012, the Dart project authors.
  * 
  * Licensed under the Eclipse Public License v1.0 (the "License"); you may not use this file except
  * in compliance with the License. You may obtain a copy of the License at
  * 
  * http://www.eclipse.org/legal/epl-v10.html
  * 
  * Unless required by applicable law or agreed to in writing, software distributed under the License
  * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
@@ skipping 85 matching lines @@
    * The file containing the VM executable.
    */
   private File vmExecutable;
 
   /**
    * A mapping from Dart library URI's to the library represented by that URI.
    */
   private LibraryMap libraryMap;
 
   /**
+   * The default SDK, or {@code null} if the default SDK either has not yet been created or cannot
+   * be created for some reason.
+   */
+  private static DirectoryBasedDartSdk DEFAULT_SDK;
+
+  /**
    * The name of the directory within the SDK directory that contains executables.
    */
   private static final String BIN_DIRECTORY_NAME = "bin"; //$NON-NLS-1$
 
   /**
    * The name of the directory on non-Mac that contains dartium.
    */
   private static final String DARTIUM_DIRECTORY_NAME = "chromium"; //$NON-NLS-1$
 
   /**
@@ skipping 89 matching lines @@
    */
   private static final String VM_EXECUTABLE_NAME = "dart"; //$NON-NLS-1$
 
   /**
    * Return the default Dart SDK, or {@code null} if the directory containing the default SDK cannot
    * be determined (or does not exist).
    * 
    * @return the default Dart SDK
    */
   public static DirectoryBasedDartSdk getDefaultSdk() {
-    File sdkDirectory = getDefaultSdkDirectory();
-    if (sdkDirectory == null) {
-      return null;
+    if (DEFAULT_SDK == null) {
+      File sdkDirectory = getDefaultSdkDirectory();
+      if (sdkDirectory == null) {
+        return null;
+      }
+      DEFAULT_SDK = new DirectoryBasedDartSdk(sdkDirectory);
     }
-    return new DirectoryBasedDartSdk(sdkDirectory);
+    return DEFAULT_SDK;
   }
 
   /**
    * Return the default directory for the Dart SDK, or {@code null} if the directory cannot be
    * determined (or does not exist). The default directory is provided by a {@link System} property
    * named {@code com.google.dart.sdk}.
    * 
    * @return the default directory for the Dart SDK
    */
   public static File getDefaultSdkDirectory() {
@@ skipping 390 matching lines @@
    * Verify that the given executable file exists and is executable.
    * 
    * @param file the binary file
    * @return the file if it exists and is executable, else {@code null}
    */
   @DartExpressionBody("file.isExecutable() ? file : null")
   private File verifyExecutable(File file) {
     return FileUtilities.ensureExecutable(file) ? file : null;
   }
 }