520ff69854
Introduces an **internal**, **experimental** `profiler` function, which
the runtime invokes around user code, including before and after:
- Running the template function of a component
- Executing a lifecycle hook
- Evaluating an output handler
The `profiler` function invokes a callback set with the global
`ng.ɵsetProfiler`. This API is **private** and **experimental** and
could be removed or changed at any time.
This implementation is cheap and available in production. It's cheap
because the `profiler` function is simple, which allows the JiT compiler
to inline it in the callsites. It also doesn't add up much to the
production bundle.
To listen for profiler events:
```ts
ng.ɵsetProfiler((event, ...args) => {
// monitor user code execution
});
```
PR Close #41255
102 lines
3.0 KiB
TypeScript
102 lines
3.0 KiB
TypeScript
/**
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* @license
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* Copyright Google LLC All Rights Reserved.
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*
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* Use of this source code is governed by an MIT-style license that can be
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* found in the LICENSE file at https://angular.io/license
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*/
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/**
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* Profiler events is an enum used by the profiler to distinguish between different calls of user
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* code invoked throughout the application lifecycle.
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*/
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export const enum ProfilerEvent {
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/**
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* Corresponds to the point in time before the runtime has called the template function of a
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* component with `RenderFlags.Create`.
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*/
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TemplateCreateStart,
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/**
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* Corresponds to the point in time after the runtime has called the template function of a
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* component with `RenderFlags.Create`.
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*/
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TemplateCreateEnd,
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/**
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* Corresponds to the point in time before the runtime has called the template function of a
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* component with `RenderFlags.Update`.
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*/
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TemplateUpdateStart,
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/**
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* Corresponds to the point in time after the runtime has called the template function of a
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* component with `RenderFlags.Update`.
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*/
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TemplateUpdateEnd,
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/**
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* Corresponds to the point in time before the runtime has called a lifecycle hook of a component
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* or directive.
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*/
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LifecycleHookStart,
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/**
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* Corresponds to the point in time after the runtime has called a lifecycle hook of a component
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* or directive.
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*/
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LifecycleHookEnd,
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/**
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* Corresponds to the point in time before the runtime has evaluated an expression associated with
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* an event or an output.
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*/
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OutputStart,
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/**
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* Corresponds to the point in time after the runtime has evaluated an expression associated with
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* an event or an output.
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*/
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OutputEnd,
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}
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/**
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* Profiler function which the runtime will invoke before and after user code.
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*/
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export interface Profiler {
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(event: ProfilerEvent, instance: {}|null, hookOrListener?: (e?: any) => any): void;
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}
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let profilerCallback: Profiler|null = null;
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/**
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* Sets the callback function which will be invoked before and after performing certain actions at
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* runtime (for example, before and after running change detection).
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*
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* Warning: this function is *INTERNAL* and should not be relied upon in application's code.
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* The contract of the function might be changed in any release and/or the function can be removed
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* completely.
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*
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* @param profiler function provided by the caller or null value to disable profiling.
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*/
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export const setProfiler = (profiler: Profiler|null) => {
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profilerCallback = profiler;
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};
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/**
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* Profiler function which wraps user code executed by the runtime.
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*
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* @param event ProfilerEvent corresponding to the execution context
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* @param instance component instance
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* @param hookOrListener lifecycle hook function or output listener. The value depends on the
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* execution context
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* @returns
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*/
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export const profiler: Profiler = function(
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event: ProfilerEvent, instance: {}|null, hookOrListener?: (e?: any) => any) {
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if (profilerCallback != null /* both `null` and `undefined` */) {
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profilerCallback(event, instance, hookOrListener);
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}
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};
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