Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/polymer/transformer.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.
+
+/// Transfomer used for pub-serve and pub-deploy.
+library polymer.transformer;
+
+import 'package:barback/barback.dart';
+import 'package:observe/transformer.dart';
+import 'package:path/path.dart' as path;
+
+import 'src/build/build_filter.dart';
+import 'src/build/common.dart';
+import 'src/build/index_page_builder.dart';
+import 'src/build/import_inliner.dart';
+import 'src/build/linter.dart';
+import 'src/build/build_log_combiner.dart';
+import 'src/build/polyfill_injector.dart';
+import 'src/build/script_compactor.dart';
+
+/// The Polymer transformer, which internally runs several phases that will:
+///   * Extract inlined script tags into their separate files
+///   * Apply the observable transformer on every Dart script.
+///   * Inline imported html files
+///   * Combine scripts from multiple files into a single script tag
+///   * Inject extra polyfills needed to run on all browsers.
+///
+/// At the end of these phases, this tranformer produces a single entrypoint
+/// HTML file with a single Dart script that can later be compiled with dart2js.
+class PolymerTransformerGroup implements TransformerGroup {
+  final Iterable<Iterable> phases;
+
+  PolymerTransformerGroup(TransformOptions options)
+      : phases = createDeployPhases(options);
+
+  PolymerTransformerGroup.asPlugin(BarbackSettings settings)
+      : this(_parseSettings(settings));
+}
+
+TransformOptions _parseSettings(BarbackSettings settings) {
+  var args = settings.configuration;
+  bool releaseMode = settings.mode == BarbackMode.RELEASE;
+  bool jsOption = args['js'];
+  bool csp = args['csp'] == true; // defaults to false
+  bool injectBuildLogs =
+      !releaseMode && args['inject_build_logs_in_output'] != false;
+  bool injectWebComponentsJs = true;
+  if (args['inject_platform_js'] != null) {
+    print(
+        'Deprecated polymer transformer option `inject_platform_js`. This has '
+        'been renamed `inject_web_components_js` to match the new file name.');
+    injectWebComponentsJs = args['inject_platform_js'] != false;
+  }
+  if (args['inject_webcomponents_js'] != null) {
+    injectWebComponentsJs = args['inject_webcomponents_js'] != false;
+  }
+  return new TransformOptions(
+      entryPoints: readFileList(args['entry_points']),
+      inlineStylesheets: _readInlineStylesheets(args['inline_stylesheets']),
+      directlyIncludeJS: jsOption == null ? releaseMode : jsOption,
+      contentSecurityPolicy: csp,
+      releaseMode: releaseMode,
+      lint: _parseLintOption(args['lint']),
+      injectBuildLogsInOutput: injectBuildLogs,
+      injectWebComponentsJs: injectWebComponentsJs);
+}
+
+// Lint option can be empty (all files), false, true, or a map indicating
+// include/exclude files.
+_parseLintOption(value) {
+  var lint = null;
+  if (value == null || value == true) return new LintOptions();
+  if (value == false) return new LintOptions.disabled();
+  if (value is Map && value.length == 1) {
+    var key = value.keys.single;
+    var files = readFileList(value[key]);
+    if (key == 'include') {
+      return new LintOptions.include(files);
+    } else if (key == 'exclude') {
+      return new LintOptions.exclude(files);
+    }
+  }
+
+  // Any other case it is an error:
+  print('Invalid value for "lint" in the polymer transformer. '
+        'Expected one of the following: \n'
+        '    lint: true  # or\n'
+        '    lint: false # or\n'
+        '    lint: \n'
+        '      include: \n'
+        '        - file1 \n'
+        '        - file2 # or \n'
+        '    lint: \n'
+        '      exclude: \n'
+        '        - file1 \n'
+        '        - file2 \n');
+  return new LintOptions();
+}
+
+readFileList(value) {
+  if (value == null) return null;
+  var files = [];
+  bool error;
+  if (value is List) {
+    files = value;
+    error = value.any((e) => e is! String);
+  } else if (value is String) {
+    files = [value];
+    error = false;
+  } else {
+    error = true;
+  }
+  if (error) {
+    print('Invalid value for "entry_points" in the polymer transformer.');
+  }
+  return files;
+}
+
+Map<String, bool> _readInlineStylesheets(settingValue) {
+  if (settingValue == null) return null;
+  var inlineStylesheets = {};
+  bool error = false;
+  if (settingValue is Map) {
+    settingValue.forEach((key, value) {
+      if (value is! bool || key is! String) {
+        error = true;
+        return;
+      }
+      if (key == 'default') {
+        inlineStylesheets[key] = value;
+        return;
+      };
+      key = systemToAssetPath(key);
+      // Special case package urls, convert to AssetId and use serialized form.
+      var packageMatch = _PACKAGE_PATH_REGEX.matchAsPrefix(key);
+      if (packageMatch != null) {
+        var package = packageMatch[1];
+        var path = 'lib/${packageMatch[2]}';
+        key = new AssetId(package, path).toString();
+      }
+      inlineStylesheets[key] = value;
+    });
+  } else if (settingValue is bool) {
+    inlineStylesheets['default'] = settingValue;
+  } else {
+    error = true;
+  }
+  if (error) {
+    print('Invalid value for "inline_stylesheets" in the polymer transformer.');
+  }
+  return inlineStylesheets;
+}
+
+/// Create deploy phases for Polymer. Note that inlining HTML Imports
+/// comes first (other than linter, if [options.linter] is enabled), which
+/// allows the rest of the HTML-processing phases to operate only on HTML that
+/// is actually imported.
+List<List<Transformer>> createDeployPhases(
+    TransformOptions options, {String sdkDir}) {
+  // TODO(sigmund): this should be done differently. We should lint everything
+  // that is reachable and have the option to lint the rest (similar to how
+  // dart2js can analyze reachable code or entire libraries).
+  var phases = options.lint.enabled ? [[new Linter(options)]] : [];
+  phases.addAll([
+    [new ImportInliner(options)],
+    [new ObservableTransformer()],
+    [new ScriptCompactor(options, sdkDir: sdkDir)],
+    [new PolyfillInjector(options)],
+    [new BuildFilter(options)],
+    [new BuildLogCombiner(options)],
+  ]);
+  if (!options.releaseMode) {
+    phases.add([new IndexPageBuilder(options)]);
+  }
+  return phases;
+}
+
+final RegExp _PACKAGE_PATH_REGEX = new RegExp(r'packages\/([^\/]+)\/(.*)');