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80 lines
3 KiB
Dart
80 lines
3 KiB
Dart
// Copyright (c) 2014, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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import "dart:async";
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import "dart:isolate";
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// This type corresponds to the VM-internal class LibraryPrefix.
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class _LibraryPrefix {
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bool _load() native "LibraryPrefix_load";
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Object _loadError() native "LibraryPrefix_loadError";
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bool isLoaded() native "LibraryPrefix_isLoaded";
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bool _invalidateDependentCode()
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native "LibraryPrefix_invalidateDependentCode";
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loadLibrary() {
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for (int i = 0; i < _outstandingLoadRequests.length; i++) {
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if (_outstandingLoadRequests[i][0] == this) {
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return _outstandingLoadRequests[i][1].future;
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}
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}
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var completer = new Completer<bool>();
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var pair = new List();
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pair.add(this);
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pair.add(completer);
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_outstandingLoadRequests.add(pair);
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Timer.run(() {
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var hasCompleted = this._load();
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// Loading can complete immediately, for example when the same
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// library has been loaded eagerly or through another deferred
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// prefix. If that is the case, we must invalidate the dependent
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// code and complete the future now since there will be no callback
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// from the VM.
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if (hasCompleted && !completer.isCompleted) {
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_invalidateDependentCode();
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completer.complete(true);
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_outstandingLoadRequests.remove(pair);
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}
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});
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return completer.future;
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}
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}
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// A list of two element lists. The first element is the _LibraryPrefix. The
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// second element is the Completer for the load request.
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var _outstandingLoadRequests = new List<List>();
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// Called from the VM when an outstanding load request has finished.
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_completeDeferredLoads() {
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// Determine which outstanding load requests have completed and complete
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// their completer (with an error or true). For outstanding load requests
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// which have not completed, remember them for next time in
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// stillOutstandingLoadRequests.
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var stillOutstandingLoadRequests = new List<List>();
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var completedLoadRequests = new List<List>();
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// Make a copy of the outstandingRequests because the call to _load below
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// may recursively trigger another call to |_completeDeferredLoads|, which
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// can cause |_outstandingLoadRequests| to be modified.
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var outstandingRequests = _outstandingLoadRequests.toList();
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for (int i = 0; i < outstandingRequests.length; i++) {
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var prefix = outstandingRequests[i][0];
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var completer = outstandingRequests[i][1];
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var error = prefix._loadError();
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if (completer.isCompleted) {
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// Already completed. Skip.
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continue;
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}
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if (error != null) {
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completer.completeError(error);
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} else if (prefix._load()) {
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prefix._invalidateDependentCode();
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completer.complete(true);
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} else {
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stillOutstandingLoadRequests.add(outstandingRequests[i]);
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}
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}
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_outstandingLoadRequests = stillOutstandingLoadRequests;
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}
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