Template parser

utils/lib/file_system.dart

+// 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.
+
+// TODO(terry): Investigate common library for file I/O shared between frog and tools.
+
+/** Abstraction for file systems and utility functions to manipulate paths. */
+#library('file_system');
+
+/**
+ * Abstraction around file system access to work in a variety of different
+ * environments.
+ */
+interface FileSystem {
+  String readAll(String filename);
+
+  void writeString(String outfile, String text);
+
+  bool fileExists(String filename);
+
+  void createDirectory(String path, [bool recursive]);
+  void removeDirectory(String path, [bool recursive]);
+}
+
+/** 
+ * Replaces all back slashes (\) with forward slashes (/) in [path] and 
+ * return the result.
+ */
+String canonicalizePath(String path) {
+  return path.replaceAll('\\', '/');
+}
+
+/** Join [path1] to [path2]. */
+String joinPaths(String path1, String path2) {
+  path1 = canonicalizePath(path1);
+  path2 = canonicalizePath(path2);
+
+  var pieces = path1.split('/');
+  for (var piece in path2.split('/')) {
+    if (piece == '..' && pieces.length > 0 && pieces.last() != '.'
+      && pieces.last() != '..') {
+      pieces.removeLast();
+    } else if (piece != '') {
+      if (pieces.length > 0 && pieces.last() == '.') {
+        pieces.removeLast();
+      }
+      pieces.add(piece);
+    }
+  }
+  return Strings.join(pieces, '/');
+}
+
+/** Returns the directory name for the [path]. */
+String dirname(String path) {
+  path = canonicalizePath(path);
+
+  int lastSlash = path.lastIndexOf('/', path.length);
+  if (lastSlash == -1) {
+    return '.';
+  } else {
+    return path.substring(0, lastSlash);
+  }
+}
+
+/** Returns the file name without directory for the [path]. */
+String basename(String path) {
+  path = canonicalizePath(path);
+
+  int lastSlash = path.lastIndexOf('/', path.length);
+  if (lastSlash == -1) {
+    return path;
+  } else {
+    return path.substring(lastSlash + 1);
+  }
+}