Refactor runtime into libraries, better type reps

lib/runtime/dart_library.js

Index: lib/runtime/dart_library.js
diff --git a/lib/runtime/dart_library.js b/lib/runtime/dart_library.js
new file mode 100644
index 0000000000000000000000000000000000000000..39394299298fda967063f289e854698cd495bc53
--- /dev/null
+++ b/lib/runtime/dart_library.js
@@ -0,0 +1,134 @@
+// Copyright (c) 2015, 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.
+
+/* This file defines the module loader for the dart runtime.
+*/
+
+var dart_library;
+(function (dart_library) {
+  'use strict';
+
+  // Module support.  This is a simplified module system for Dart.
+  // Longer term, we can easily migrate to an existing JS module system:
+  // ES6, AMD, RequireJS, ....
+
+  class LibraryLoader {
+    constructor(name, defaultValue, imports, lazyImports, loader) {
+      this._name = name;
+      this._library = defaultValue ? defaultValue : {};
+      this._imports = imports;
+      this._lazyImports = lazyImports;
+      this._loader = loader;
+
+      // Cyclic import detection
+      this._state = LibraryLoader.NOT_LOADED;
+    }
+
+    loadImports(pendingSet) {
+      return this.handleImports(this._imports, (lib) => lib.load(pendingSet));
+    }
+
+    deferLazyImports(pendingSet) {
+      return this.handleImports(this._lazyImports,
+        (lib) => {
+          pendingSet.add(lib._name);
+          return lib.stub();
+      });
+    }
+
+    loadLazyImports(pendingSet) {
+      return this.handleImports(pendingSet, (lib) => lib.load());
+    }
+
+    handleImports(list, handler) {
+      let results = [];
+      for (let name of list) {
+        let lib = libraries[name];
+        if (!lib) {
+          dart_utils.throwError('Library not available: ' + name);
+        }
+        results.push(handler(lib));
+      }
+      return results;
+    }
+
+    load(inheritedPendingSet) {
+      // Check for cycles
+      if (this._state == LibraryLoader.LOADING) {
+        dart_utils.throwError('Circular dependence on library: '
+                              + this._name);
+      } else if (this._state >= LibraryLoader.LOADED) {
+        return this._library;
+      }
+      this._state = LibraryLoader.LOADING;
+
+      // Handle imports and record lazy imports
+      let pendingSet = inheritedPendingSet ? inheritedPendingSet : new Set();
+      let args = this.loadImports(pendingSet);
+      args = args.concat(this.deferLazyImports(pendingSet));
+
+      // Load the library
+      args.unshift(this._library);
+      this._loader.apply(null, args);
+      this._state = LibraryLoader.LOADED;
+
+      // Handle lazy imports
+      if (inheritedPendingSet === void 0) {
+        // Drain the queue
+        this.loadLazyImports(pendingSet);
+      }
+      this._state = LibraryLoader.READY;
+      return this._library;
+    }
+
+    stub() {
+      return this._library;
+    }
+  }
+  LibraryLoader.NOT_LOADED = 0;
+  LibraryLoader.LOADING = 1;
+  LibraryLoader.LOADED = 2;
+  LibraryLoader.READY = 3;
+
+  // Map from name to LibraryLoader
+  let libraries = new Map();
+
+  function library(name, defaultValue, imports, lazyImports, loader) {
+    return libraries[name] =
+      new LibraryLoader(name, defaultValue, imports, lazyImports, loader);
+  }
+  dart_library.library = library;
+
+  function import_(libraryName) {
+    bootstrap();
+    let loader = libraries[libraryName];
+    return loader.load();
+  }
+  dart_library.import = import_;
+
+  function start(libraryName) {
+    let library = import_(libraryName);
+    let _isolate_helper = import_('dart/_isolate_helper');
+    _isolate_helper.startRootIsolate(library.main, []);
+  }
+  dart_library.start = start;
+
+  let _bootstrapped = false;
+  function bootstrap() {
+    if (_bootstrapped) return;
+    _bootstrapped = true;
+
+   // Force import of core.
+    import_('dart/core');
+
+    // TODO(vsm): DOM facades?
+    // See: https://github.com/dart-lang/dev_compiler/issues/173
+    NodeList.prototype.get = function(i) { return this[i]; };
+    NamedNodeMap.prototype.get = function(i) { return this[i]; };
+    DOMTokenList.prototype.get = function(i) { return this[i]; };
+    HTMLCollection.prototype.get = function(i) { return this[i]; };
+
+  }
+
+})(dart_library || (dart_library = {}));