Bring back initPolymer, allow boot.js only if using "polymer_experimental.html".

pkg/polymer/lib/boot.dart

-// Copyright (c) 2014, 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.
-
-/// Bootstrap to initialize polymer applications. This library is not in use
-/// yet but it will replace boot.js in the near future (see dartbug.com/18007).
-///
-/// This script contains logic to bootstrap polymer apps during development. It
-/// internally discovers special Dart script tags through HTML imports, and
-/// constructs a new entrypoint for the application that is then launched in an
-/// isolate.
-///
-/// For each script tag found, we will load the corresponding Dart library and
-/// execute all methods annotated with `@initMethod` and register all classes
-/// labeled with `@CustomTag`. We keep track of the order of imports and execute
-/// initializers in the same order.
-///
-/// All polymer applications use this bootstrap logic. It is included
-/// automatically when you include the polymer.html import:
-///
-///    <link rel="import" href="packages/polymer/polymer.html">
-///
-/// There are two important changes compared to previous versions of polymer
-/// (0.10.0-pre.6 and older):
-///
-///   * Use 'application/dart;component=1' instead of 'application/dart':
-///   Dartium already limits to have a single script tag per document, but it
-///   will be changing semantics soon and make them even stricter. Multiple
-///   script tags are not going to be running on the same isolate after this
-///   change. For polymer applications we'll use a parameter on the script tags
-///   mime-type to prevent Dartium from loading them separately. Instead this
-///   bootstrap script combines those special script tags and creates the
-///   application Dartium needs to run.
-///
-//    If you had:
-///
-///      <polymer-element name="x-foo"> ...
-///      <script type="application/dart" src="x_foo.dart'></script>
-///
-///   Now you need to write:
-///
-///      <polymer-element name="x-foo"> ...
-///      <script type="application/dart;component=1" src="x_foo.dart'></script>
-///
-///   * `initPolymer` is gone: we used to initialize applications in two
-///   possible ways: using init.dart or invoking initPolymer in your main. Any
-///   of these initialization patterns can be replaced to use an `@initMethod`
-///   instead. For example, If you need to run some initialization code before
-///   any other code is executed, include a "application/dart;component=1"
-///   script tag that contains an initializer method with the body of your old
-///   main, and make sure this tag is placed above other html-imports that load
-///   the rest of the application. Initialization methods are executed in the
-///   order in which they are discovered in the HTML document.
-library polymer.src.boot;
-
-import 'dart:html';
-import 'dart:mirrors';
-
-main() {
-  var scripts = _discoverScripts(document, window.location.href);
-  var sb = new StringBuffer()..write('library bootstrap;\n\n');
-  int count = 0;
-  for (var s in scripts) {
-    sb.writeln("import '$s' as prefix_$count;");
-    count++;
-  }
-  sb.writeln("import 'package:polymer/src/mirror_loader.dart';");
-  sb.write('\nmain() => startPolymerInDevelopment([\n');
-  for (var s in scripts) {
-    sb.writeln("  '$s',");
-  }
-  sb.write(']);\n');
-  var isolateUri = _asDataUri(sb.toString());
-  spawnDomUri(Uri.parse(isolateUri), [], '');
-}
-
-/// Internal state used in [_discoverScripts].
-class _State {
-  /// Documents that we have visited thus far.
-  final Set<Document> seen = new Set();
-
-  /// Scripts that have been discovered, in tree order.
-  final List<String> scripts = [];
-
-  /// Whether we've seen a type="application/dart" script tag, since we expect
-  /// to have only one of those.
-  bool scriptSeen = false;
-}
-
-/// Walks the HTML import structure to discover all script tags that are
-/// implicitly loaded. This code is only used in Dartium and should only be
-/// called after all HTML imports are resolved. Polymer ensures this by asking
-/// users to put their Dart script tags after all HTML imports (this is checked
-/// by the linter, and Dartium will otherwise show an error message).
-List<String> _discoverScripts(Document doc, String baseUri, [_State state]) {
-  if (state == null) state = new _State();
-  if (doc == null) {
-    print('warning: $baseUri not found.');
-    return state.scripts;
-  }
-  if (!state.seen.add(doc)) return state.scripts;
-
-  for (var node in doc.querySelectorAll('script,link[rel="import"]')) {
-    if (node is LinkElement) {
-      _discoverScripts(node.import, node.href, state);
-    } else if (node is ScriptElement) {
-      if (node.type == 'application/dart;component=1') {
-        if (node.src != '' ||
-            node.text != "export 'package:polymer/boot.dart';") {
-          state.scripts.add(_getScriptUrl(node));
-        }
-      }
-
-      if (node.type == 'application/dart') {
-        if (state.scriptSeen) {
-          print('Dartium currently only allows a single Dart script tag '
-              'per application, and in the future it will run them in '
-              'separtate isolates.  To prepare for this Dart script '
-              'tags need to be updated to use the mime-type '
-              '"application/dart;component=1" instead of "application/dart":');
-        }
-        state.scriptSeen = true;
-      }
-    }
-  }
-  return state.scripts;
-}
-
-// TODO(sigmund): explore other (cheaper) ways to resolve URIs relative to the
-// root library (see dartbug.com/12612)
-final _rootUri = currentMirrorSystem().isolate.rootLibrary.uri;
-
-/// Returns a URI that can be used to load the contents of [script] in a Dart
-/// import. This is either the source URI if [script] has a `src` attribute, or
-/// a base64 encoded `data:` URI if the [script] contents are inlined.
-String _getScriptUrl(script) {
-  var uriString = script.src;
-  if (uriString != '') {
-    var uri = _rootUri.resolve(uriString);
-    if (!_isHttpStylePackageUrl(uri)) return '$uri';
-    // Use package: urls if available. This rule here is more permissive than
-    // how we translate urls in polymer-build, but we expect Dartium to limit
-    // the cases where there are differences. The polymer-build issues an error
-    // when using packages/ inside lib without properly stepping out all the way
-    // to the packages folder. If users don't create symlinks in the source
-    // tree, then Dartium will also complain because it won't find the file seen
-    // in an HTML import.
-    var packagePath = uri.path.substring(
-        uri.path.lastIndexOf('packages/') + 'packages/'.length);
-    return 'package:$packagePath';
-  }
-
-  return _asDataUri(script.text);
-}
-
-/// Whether [uri] is an http URI that contains a 'packages' segment, and
-/// therefore could be converted into a 'package:' URI.
-bool _isHttpStylePackageUrl(Uri uri) {
-  var uriPath = uri.path;
-  return uri.scheme == _rootUri.scheme &&
-      // Don't process cross-domain uris.
-      uri.authority == _rootUri.authority &&
-      uriPath.endsWith('.dart') &&
-      (uriPath.contains('/packages/') || uriPath.startsWith('packages/'));
-}
-
-/// Returns a base64 `data:` uri with the contents of [s].
-// TODO(sigmund): change back to application/dart: using text/javascript seems
-// wrong but it hides a warning in Dartium (dartbug.com/18000).
-_asDataUri(s) => 'data:text/javascript;base64,${window.btoa(s)}';