| // 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. |
| |
| /// Experimental bootstrap to initialize polymer applications. This library is |
| /// not used by default, and may be replaced by Dart code in the near future. |
| /// |
| /// This script contains logic to bootstrap polymer apps during development. It |
| /// internally discovers 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. |
| /// |
| /// You can this experimental bootstrap logic by including the |
| /// polymer_experimental.html import, instead of polymer.html: |
| /// |
| /// <link rel="import" href="packages/polymer/polymer_experimental.html"> |
| /// |
| /// This bootstrap replaces `initPolymer` so Dart code might need to be changed |
| /// too. If you loaded init.dart directly, you can remove it. But if you invoke |
| /// initPolymer in your main, you should remove that call and change to use |
| /// `@initMethod` instead. The current bootstrap doesn't support having Dart |
| /// script tags in the main page, so you may need to move some code into an HTML |
| /// import. For example, If you need to run some initialization code before any |
| /// other code is executed, include an HTML import to an html file with a |
| /// "application/dart" 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. |
| (function() { |
| // Only run in Dartium. |
| if (!navigator.dartEnabled && |
| // TODO(sigmund): remove userAgent check once 1.6 rolls as stable. |
| // See: dartbug.com/18463 |
| (navigator.userAgent.indexOf('(Dart)') === -1)) { |
| return; |
| } |
| |
| // Extract a Dart import URL from a script tag, which is the 'src' attribute |
| // of the script tag, or a data-url with the script contents for inlined code. |
| function getScriptUrl(script) { |
| var url = script.src; |
| if (url) { |
| // Normalize package: urls |
| var index = url.indexOf('packages/'); |
| if (index == 0 || (index > 0 && url[index - 1] == '/')) { |
| url = "package:" + url.slice(index + 9); |
| } |
| return url; |
| } |
| |
| // TODO(sigmund): change back to application/dart: using application/json is |
| // wrong but it hides a warning in Dartium (dartbug.com/18000). |
| return "data:application/json;base64," + window.btoa(script.textContent); |
| } |
| |
| // Creates a Dart program that imports [urls] and passes them to |
| // startPolymerInDevelopment, which in turn will invoke methods marked with |
| // @initMethod, and register any custom tag labeled with @CustomTag in those |
| // libraries. |
| function createMain(urls, mainUrl) { |
| var imports = Array(urls.length + 1); |
| for (var i = 0; i < urls.length; ++i) { |
| imports[i] = 'import "' + urls[i] + '" as i' + i + ';'; |
| } |
| imports[urls.length] = 'import "package:polymer/src/mirror_loader.dart";'; |
| var arg = urls.length == 0 ? '[]' : |
| ('[\n "' + urls.join('",\n "') + '"\n ]'); |
| return (imports.join('\n') + |
| '\n\nmain() {\n' + |
| ' startPolymerInDevelopment(' + arg + ');\n' + |
| '}\n'); |
| } |
| |
| function discoverScripts(content, state, importedDoc) { |
| if (!state) { |
| // internal state tracking documents we've visited, the resulting list of |
| // scripts, and any tags with the incorrect mime-type. |
| state = {seen: {}, scripts: [], badTags: []}; |
| } |
| if (!content) return state; |
| |
| // Note: we visit both script and link-imports together to ensure we |
| // preserve the order of the script tags as they are discovered. |
| var nodes = content.querySelectorAll('script,link[rel="import"]'); |
| for (var i = 0; i < nodes.length; i++) { |
| var node = nodes[i]; |
| if (node instanceof HTMLLinkElement) { |
| // TODO(jmesserly): figure out why ".import" fails in content_shell but |
| // works in Dartium. |
| if (node.import && node.import.href) node = node.import; |
| |
| if (state.seen[node.href]) continue; |
| state.seen[node.href] = node; |
| discoverScripts(node.import, state, true); |
| } else if (node instanceof HTMLScriptElement) { |
| if (node.type != 'application/dart') continue; |
| if (importedDoc) { |
| state.scripts.push(getScriptUrl(node)); |
| } else { |
| state.badTags.push(node); |
| } |
| } |
| } |
| return state; |
| } |
| |
| // TODO(jmesserly): we're using this function because DOMContentLoaded can |
| // be fired too soon: https://www.w3.org/Bugs/Public/show_bug.cgi?id=23526 |
| HTMLImports.whenImportsReady(function() { |
| // Append a new script tag that initializes everything. |
| var newScript = document.createElement('script'); |
| newScript.type = "application/dart"; |
| |
| var results = discoverScripts(document); |
| if (results.badTags.length > 0) { |
| console.warn('The experimental polymer boostrap does not support ' |
| + 'having script tags in the main document. You can move the script ' |
| + 'tag to an HTML import instead. Also make sure your script tag ' |
| + 'doesn\'t have a main, but a top-level method marked with ' |
| + '@initMethod instead'); |
| for (var i = 0; i < results.badTags.length; i++) { |
| console.warn(results.badTags[i]); |
| } |
| } |
| newScript.textContent = createMain(results.scripts); |
| document.body.appendChild(newScript); |
| }); |
| })(); |