Initial new file FileUtils with a single public static method.

compiler/java/com/google/dart/compiler/util/apache/FileUtils.java

Index: compiler/java/com/google/dart/compiler/util/apache/FileUtils.java
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--- compiler/java/com/google/dart/compiler/util/apache/FileUtils.java	(revision 0)
+++ compiler/java/com/google/dart/compiler/util/apache/FileUtils.java	(revision 0)
@@ -0,0 +1,64 @@
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (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.apache.org/licenses/LICENSE-2.0
+ *
+ * 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 or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.dart.compiler.util.apache;
+
+import java.io.File;
+import java.net.URL;
+
+/**
+ * General file manipulation utilities.
+ * * <p>
+ * NOTICE: This file is modified copy of its original Apache library.
+ * It was moved to the different package, and changed to reduce number of dependencies.
+ */
+public class FileUtils {
+  /**
+   * Convert from a <code>URL</code> to a <code>File</code>.
+   * <p>
+   * From version 1.1 this method will decode the URL.
+   * Syntax such as <code>file:///my%20docs/file.txt</code> will be
+   * correctly decoded to <code>/my docs/file.txt</code>. Starting with version
+   * 1.5, this method uses UTF-8 to decode percent-encoded octets to characters.
+   * Additionally, malformed percent-encoded octets are handled leniently by
+   * passing them through literally.
+   *
+   * @param url  the file URL to convert, <code>null</code> returns <code>null</code>
+   * @return the equivalent <code>File</code> object, or <code>null</code>
+   *  if the URL's protocol is not <code>file</code>
+   */
+  public static File toFile(URL url) {
+    if (url == null || !url.getProtocol().equals("file")) {
+      return null;
+    } else {
+      String filename = url.getFile().replace('/', File.separatorChar);
+      int pos = 0;
+      while ((pos = filename.indexOf('%', pos)) >= 0) {
+        if (pos + 2 < filename.length()) {
+          String hexStr = filename.substring(pos + 1, pos + 3);
+          char ch = (char) Integer.parseInt(hexStr, 16);
+          filename = filename.substring(0, pos) + ch + filename.substring(pos + 3);
+        }
+      }
+      return new File(filename);
+    }
+  }
+
+}