pdf.js/src/shared/streams_polyfill.js
Jonas Jenwald 249b199ff1 Stop bundling the ReadableStream polyfill in MOZCENTRAL builds (PR 10470 follow-up)
Based on the discussion in https://bugzilla.mozilla.org/show_bug.cgi?id=1521413, this patch simply removes the `ReadableStream` polyfill completely from MOZCENTRAL builds.

With this patch, the size of the `gulp mozcentral` build target is thus further reduced (building on PR 10470):

|       | `build/mozcentral`
|-------|-------------------
|master |   3 339 666
|patch  |   3 209 572
2019-01-23 20:33:20 +01:00

56 lines
2.0 KiB
JavaScript

/* Copyright 2017 Mozilla Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* eslint-disable no-restricted-globals */
if (typeof PDFJSDev !== 'undefined' && PDFJSDev.test('MOZCENTRAL')) {
if (typeof ReadableStream === 'undefined') {
throw new Error('Please enable ReadableStream support by resetting the ' +
'"javascript.options.streams" preference to "true" in about:config.');
}
exports.ReadableStream = ReadableStream;
} else {
let isReadableStreamSupported = false;
if (typeof ReadableStream !== 'undefined') {
// MS Edge may say it has ReadableStream but they are not up to spec yet.
try {
// eslint-disable-next-line no-new
new ReadableStream({
start(controller) {
controller.close();
},
});
isReadableStreamSupported = true;
} catch (e) {
// The ReadableStream constructor cannot be used.
}
}
if (isReadableStreamSupported) {
exports.ReadableStream = ReadableStream;
} else if (typeof PDFJSDev !== 'undefined' &&
PDFJSDev.test('IMAGE_DECODERS')) {
class DummyReadableStream {
constructor() {
throw new Error('The current image decoders are synchronous, ' +
'hence `ReadableStream` shouldn\'t need to be ' +
'polyfilled for the IMAGE_DECODERS build target.');
}
}
exports.ReadableStream = DummyReadableStream;
} else {
exports.ReadableStream =
require('../../external/streams/streams-lib').ReadableStream;
}
}