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'use strict';
const { Session } = require('inspector');
const { promisify } = require('util');
class CoverageInstrumenter {
constructor() {
this.session = new Session();
this.postSession = promisify(this.session.post.bind(this.session));
}
async startInstrumenting() {
this.session.connect();
await this.postSession('Profiler.enable');
await this.postSession('Profiler.startPreciseCoverage', {
callCount: true,
detailed: true,
});
}
async stopInstrumenting() {
const {result} = await this.postSession(
'Profiler.takePreciseCoverage',
);
await this.postSession('Profiler.stopPreciseCoverage');
await this.postSession('Profiler.disable');
// When using networked filesystems on Windows, v8 sometimes returns URLs
// of the form file:////<host>/path. These URLs are not well understood
// by NodeJS (see https://github.com/nodejs/node/issues/48530).
// We circumvent this issue here by fixing these URLs.
// FWIW, Python has special code to deal with URLs like this
// https://github.com/python/cpython/blob/bef1c8761e3b0dfc5708747bb646ad8b669cbd67/Lib/nturl2path.py#L22C1-L22C1
if (process.platform === 'win32') {
const prefix = 'file:////';
result.forEach(res => {
if (res.url.startsWith(prefix)) {
res.url = 'file://' + res.url.slice(prefix.length);
}
})
}
return result;
}
}
module.exports.CoverageInstrumenter = CoverageInstrumenter;