Jacob Richman
9484ac8bdf
BUG= R=vsm@google.com Review-Url: https://codereview.chromium.org/2752163002 .
50 lines
1.7 KiB
Dart
50 lines
1.7 KiB
Dart
// Copyright (c) 2013, 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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/// dart2js "primitives", that is, features that cannot be implemented without
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/// access to JavaScript features.
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library dart2js._js_primitives;
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import 'dart:_foreign_helper' show JS;
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/**
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* This is the low-level method that is used to implement [print]. It is
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* possible to override this function from JavaScript by defining a function in
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* JavaScript called "dartPrint".
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*
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* Notice that it is also possible to intercept calls to [print] from within a
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* Dart program using zones. This means that there is no guarantee that a call
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* to print ends in this method.
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*/
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void printString(String string) {
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if (JS('bool', r'typeof dartPrint == "function"')) {
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// Support overriding print from JavaScript.
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JS('void', r'dartPrint(#)', string);
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return;
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}
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// Inside browser or nodejs.
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if (JS('bool', r'typeof console == "object"') &&
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JS('bool', r'typeof console.log != "undefined"')) {
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JS('void', r'console.log(#)', string);
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return;
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}
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// Don't throw inside IE, the console is only defined if dev tools is open.
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if (JS('bool', r'typeof window == "object"')) {
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return;
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}
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// Running in d8, the V8 developer shell, or in Firefox' js-shell.
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if (JS('bool', r'typeof print == "function"')) {
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JS('void', r'print(#)', string);
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return;
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}
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// This is somewhat nasty, but we don't want to drag in a bunch of
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// dependencies to handle a situation that cannot happen. So we
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// avoid using Dart [:throw:] and Dart [toString].
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JS('void', 'throw "Unable to print message: " + String(#)', string);
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}
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