move polymer.dart into dart svn

pkg/polymer/lib/src/paths.dart

+// Copyright (c) 2013, 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.
+
+/**
+ * Holds path information that is used by the WebUI compiler to find files,
+ * compute their output location and relative paths between them.
+ */
+library polymer.src.paths;
+
+import 'info.dart' show UrlInfo;
+import 'messages.dart';
+import 'summary.dart';
+import 'utils.dart' show path, pathToUrl;
+
+/**
+ * Stores information about paths and computes mappings between input and output
+ * path locations.
+ */
+class PathMapper {
+  /**
+   * Common prefix to all input paths that are read from the file system. The
+   * output generated by the compiler will reflect the directory structure
+   * starting from [_baseDir]. For instance, if [_baseDir] is `a/b/c` and
+   * [_outputDir] is `g/h/`, then the corresponding output file for
+   * `a/b/c/e/f.html` will be under `g/h/e/f.html.dart`.
+   */
+  final String _baseDir;
+
+  /** Base path where all output is generated. */
+  final String _outputDir;
+
+  /** The package root directory. */
+  final String packageRoot;
+
+  /** Whether to add prefixes and to output file names. */
+  final bool _mangleFilenames;
+
+  final bool _rewriteUrls;
+
+  bool get _rewritePackageImports => _rewriteUrls || !_mangleFilenames;
+
+  /** Default prefix added to all filenames. */
+  static const String _DEFAULT_PREFIX = '_';
+
+  PathMapper(String baseDir, String outputDir, this.packageRoot,
+      bool forceMangle, this._rewriteUrls)
+      : _baseDir = baseDir,
+        _outputDir = outputDir,
+        _mangleFilenames = forceMangle || (baseDir == outputDir);
+
+  /** Add a prefix and [suffix] if [_mangleFilenames] is true */
+  String mangle(String name, String suffix, [bool forceSuffix = false]) =>
+    _mangleFilenames ? "$_DEFAULT_PREFIX$name$suffix"
+        : (forceSuffix ? "$name$suffix" : name);
+
+  /**
+   * Checks that `input.resolvedPath` is a valid input path. It must be in
+   * [_baseDir] and must not be in the [_outputDir]. If not, an error message
+   * is added to [messages].
+   */
+  bool checkInputPath(UrlInfo input, Messages messages) {
+    if (_mangleFilenames) return true;
+    var canonicalized = path.normalize(input.resolvedPath);
+    var parentDir = '..${path.separator}';
+    if (!path.relative(canonicalized, from: _outputDir).startsWith(parentDir)) {
+      messages.error(
+          'The file ${input.resolvedPath} cannot be processed. '
+          'Files cannot be under the output folder (${_outputDir}).',
+          input.sourceSpan);
+      return false;
+    }
+    if (path.relative(canonicalized, from: _baseDir).startsWith(parentDir)) {
+      messages.error(
+          'The file ${input.resolvedPath} cannot be processed. '
+          'All processed files must be under the base folder (${_baseDir}), you'
+          ' can specify the base folder using the --basedir flag.',
+          input.sourceSpan);
+      return false;
+    }
+    return true;
+  }
+
+  /**
+   * The path to the output file corresponding to [input], by adding
+   * [_DEFAULT_PREFIX] and a [suffix] to its file name.
+   */
+  String outputPath(String input, String suffix, [bool forceSuffix = false]) =>
+      path.join(outputDirPath(input),
+          mangle(path.basename(input), suffix, forceSuffix));
+
+  /** The path to the output file corresponding to [info]. */
+  String outputLibraryPath(LibrarySummary lib) =>
+      path.join(outputDirPath(lib.dartCodeUrl.resolvedPath),
+          lib.outputFilename);
+
+  /** The corresponding output directory for [input]'s directory. */
+  String outputDirPath(String input) {
+    return _rewritePackages(path.normalize(
+          path.join(_outputDir, path.relative(
+              path.dirname(input), from: _baseDir))));
+  }
+
+  /**
+   * We deal with `packages/` directories in a very special way. We assume it
+   * points to resources loaded from other pub packages. If an output directory
+   * is specified, the compiler will create a packages symlink so that
+   * `package:` imports work.
+   *
+   * To make it possible to share components through pub, we allow using tags of
+   * the form `<link rel="import" href="packages/...">`, so that you can
+   * refer to components within the packages symlink.  Regardless of whether an
+   * --out option was given to the compiler, we don't want to generate files
+   * inside `packages/` for those components.  Instead we will generate such
+   * code in a special directory called `_from_packages/`.
+   */
+  String _rewritePackages(String outputPath) {
+    // TODO(jmesserly): this should match against packageRoot instead.
+    if (!outputPath.contains('packages')) return outputPath;
+    if (!_rewritePackageImports) return outputPath;
+    var segments = path.split(outputPath);
+    return path.joinAll(
+        segments.map((s) => s == 'packages' ? '_from_packages' : s));
+  }
+
+  /**
+   * Returns a url to import/export the output library represented by [target]
+   * from the output library of [src]. In other words, a url to import or export
+   * `target.outputFilename` from `src.outputFilename`.
+   */
+  String importUrlFor(LibrarySummary src, LibrarySummary target) {
+    if (!_rewritePackageImports &&
+        target.dartCodeUrl.url.startsWith('package:')) {
+      return pathToUrl(path.join(path.dirname(target.dartCodeUrl.url),
+            target.outputFilename));
+    }
+    var srcDir = path.dirname(src.dartCodeUrl.resolvedPath);
+    var relDir = path.relative(
+        path.dirname(target.dartCodeUrl.resolvedPath), from: srcDir);
+    return pathToUrl(_rewritePackages(path.normalize(
+          path.join(relDir, target.outputFilename))));
+  }
+
+  /**
+   * Transforms a [target] url seen in [src] (e.g. a Dart import, a .css href in
+   * an HTML file, etc) into a corresponding url from the output file associated
+   * with [src]. This will keep 'package:', 'dart:', path-absolute, and absolute
+   * urls intact, but it will fix relative paths to walk from the output
+   * directory back to the input directory. An exception will be thrown if
+   * [target] is not under [_baseDir].
+   */
+  String transformUrl(String src, String target) {
+    var uri = Uri.parse(target);
+    if (uri.isAbsolute) return target;
+    if (!uri.scheme.isEmpty) return target;
+    if (!uri.host.isEmpty) return target;
+    if (uri.path.isEmpty) return target;  // Implies standalone ? or # in URI.
+    if (path.isAbsolute(target)) return target;
+
+    return pathToUrl(path.normalize(path.relative(
+          path.join(path.dirname(src), target), from: outputDirPath(src))));
+  }
+}
+
+/**
+ * Returns a "mangled" name, with a prefix and [suffix] depending on the
+ * compiler's settings. [forceSuffix] causes [suffix] to be appended even if
+ * the compiler is not mangling names.
+ */
+typedef String NameMangler(String name, String suffix, [bool forceSuffix]);