puppeteer/lib/Tracing.js

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/**
* Copyright 2017 Google Inc. All rights reserved.
*
* 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.
*/
const {helper, assert} = require('./helper');
class Tracing {
/**
* @param {!Puppeteer.CDPSession} client
*/
constructor(client) {
this._client = client;
this._recording = false;
this._path = '';
}
/**
* @param {!{path?: string, screenshots?: boolean, categories?: !Array<string>}} options
*/
async start(options = {}) {
assert(!this._recording, 'Cannot start recording trace while already recording trace.');
const defaultCategories = [
'-*', 'devtools.timeline', 'v8.execute', 'disabled-by-default-devtools.timeline',
'disabled-by-default-devtools.timeline.frame', 'toplevel',
'blink.console', 'blink.user_timing', 'latencyInfo', 'disabled-by-default-devtools.timeline.stack',
'disabled-by-default-v8.cpu_profiler', 'disabled-by-default-v8.cpu_profiler.hires'
];
const {
path = null,
screenshots = false,
categories = defaultCategories,
} = options;
if (screenshots)
categories.push('disabled-by-default-devtools.screenshot');
this._path = path;
this._recording = true;
await this._client.send('Tracing.start', {
transferMode: 'ReturnAsStream',
categories: categories.join(',')
});
}
/**
* @return {!Promise<!Buffer>}
*/
async stop() {
let fulfill;
const contentPromise = new Promise(x => fulfill = x);
this._client.once('Tracing.tracingComplete', event => {
helper.readProtocolStream(this._client, event.stream, this._path).then(fulfill);
});
await this._client.send('Tracing.end');
this._recording = false;
return contentPromise;
}
}
module.exports = Tracing;