GT2/Ejectable/node_modules/react-native/Libraries/Performance/Systrace.js

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2021-08-16 00:14:59 +00:00
/**
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @flow
* @format
*/
'use strict';
const invariant = require('invariant');
const TRACE_TAG_REACT_APPS = 1 << 17; // eslint-disable-line no-bitwise
const TRACE_TAG_JS_VM_CALLS = 1 << 27; // eslint-disable-line no-bitwise
let _enabled = false;
let _asyncCookie = 0;
const _markStack = [];
let _markStackIndex = -1;
let _canInstallReactHook = false;
// Implements a subset of User Timing API necessary for React measurements.
// https://developer.mozilla.org/en-US/docs/Web/API/User_Timing_API
const REACT_MARKER = '\u269B';
const userTimingPolyfill = __DEV__
? {
mark(markName: string) {
if (_enabled) {
_markStackIndex++;
_markStack[_markStackIndex] = markName;
let systraceLabel = markName;
// Since perf measurements are a shared namespace in User Timing API,
// we prefix all React results with a React emoji.
if (markName[0] === REACT_MARKER) {
// This is coming from React.
// Removing component IDs keeps trace colors stable.
const indexOfId = markName.lastIndexOf(' (#');
const cutoffIndex = indexOfId !== -1 ? indexOfId : markName.length;
// Also cut off the emoji because it breaks Systrace
systraceLabel = markName.slice(2, cutoffIndex);
}
Systrace.beginEvent(systraceLabel);
}
},
measure(measureName: string, startMark: ?string, endMark: ?string) {
if (_enabled) {
invariant(
typeof measureName === 'string' &&
typeof startMark === 'string' &&
typeof endMark === 'undefined',
'Only performance.measure(string, string) overload is supported.',
);
const topMark = _markStack[_markStackIndex];
invariant(
startMark === topMark,
'There was a mismatching performance.measure() call. ' +
'Expected "%s" but got "%s."',
topMark,
startMark,
);
_markStackIndex--;
// We can't use more descriptive measureName because Systrace doesn't
// let us edit labels post factum.
Systrace.endEvent();
}
},
clearMarks(markName: string) {
if (_enabled) {
if (_markStackIndex === -1) {
return;
}
if (markName === _markStack[_markStackIndex]) {
// React uses this for "cancelling" started measurements.
// Systrace doesn't support deleting measurements, so we just stop them.
if (userTimingPolyfill != null) {
userTimingPolyfill.measure(markName, markName);
}
}
}
},
clearMeasures() {
// React calls this to avoid memory leaks in browsers, but we don't keep
// measurements anyway.
},
}
: null;
function installPerformanceHooks(polyfill) {
if (polyfill) {
if (global.performance === undefined) {
global.performance = {};
}
Object.keys(polyfill).forEach(methodName => {
if (typeof global.performance[methodName] !== 'function') {
global.performance[methodName] = polyfill[methodName];
}
});
}
}
const Systrace = {
installReactHook() {
if (_enabled) {
if (__DEV__) {
installPerformanceHooks(userTimingPolyfill);
}
}
_canInstallReactHook = true;
},
setEnabled(enabled: boolean) {
if (_enabled !== enabled) {
if (__DEV__) {
if (enabled) {
global.nativeTraceBeginLegacy &&
global.nativeTraceBeginLegacy(TRACE_TAG_JS_VM_CALLS);
} else {
global.nativeTraceEndLegacy &&
global.nativeTraceEndLegacy(TRACE_TAG_JS_VM_CALLS);
}
if (_canInstallReactHook) {
if (enabled) {
installPerformanceHooks(userTimingPolyfill);
}
}
}
_enabled = enabled;
}
},
isEnabled(): boolean {
return _enabled;
},
/**
* beginEvent/endEvent for starting and then ending a profile within the same call stack frame
**/
beginEvent(profileName?: any, args?: any) {
if (_enabled) {
profileName =
typeof profileName === 'function' ? profileName() : profileName;
global.nativeTraceBeginSection(TRACE_TAG_REACT_APPS, profileName, args);
}
},
endEvent() {
if (_enabled) {
global.nativeTraceEndSection(TRACE_TAG_REACT_APPS);
}
},
/**
* beginAsyncEvent/endAsyncEvent for starting and then ending a profile where the end can either
* occur on another thread or out of the current stack frame, eg await
* the returned cookie variable should be used as input into the endAsyncEvent call to end the profile
**/
beginAsyncEvent(profileName?: any): any {
const cookie = _asyncCookie;
if (_enabled) {
_asyncCookie++;
profileName =
typeof profileName === 'function' ? profileName() : profileName;
global.nativeTraceBeginAsyncSection(
TRACE_TAG_REACT_APPS,
profileName,
cookie,
);
}
return cookie;
},
endAsyncEvent(profileName?: any, cookie?: any) {
if (_enabled) {
profileName =
typeof profileName === 'function' ? profileName() : profileName;
global.nativeTraceEndAsyncSection(
TRACE_TAG_REACT_APPS,
profileName,
cookie,
);
}
},
/**
* counterEvent registers the value to the profileName on the systrace timeline
**/
counterEvent(profileName?: any, value?: any) {
if (_enabled) {
profileName =
typeof profileName === 'function' ? profileName() : profileName;
global.nativeTraceCounter &&
global.nativeTraceCounter(TRACE_TAG_REACT_APPS, profileName, value);
}
},
};
if (__DEV__) {
// This is needed, because require callis in polyfills are not processed as
// other files. Therefore, calls to `require('moduleId')` are not replaced
// with numeric IDs
// TODO(davidaurelio) Scan polyfills for dependencies, too (t9759686)
(require: any).Systrace = Systrace;
}
module.exports = Systrace;