angular-docs-cn/dev-infra/pullapprove/condition_evaluator.ts

100 lines
3.9 KiB
TypeScript

/**
* @license
* Copyright Google LLC All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import {IMinimatch, Minimatch} from 'minimatch';
/** Map that holds patterns and their corresponding Minimatch globs. */
const patternCache = new Map<string, IMinimatch>();
/**
* Context that is provided to conditions. Conditions can use various helpers
* that PullApprove provides. We try to mock them here. Consult the official
* docs for more details: https://docs.pullapprove.com/config/conditions.
*/
const conditionContext = {
'len': (value: any[]) => value.length,
'contains_any_globs': (files: PullApproveArray, patterns: string[]) => {
// Note: Do not always create globs for the same pattern again. This method
// could be called for each source file. Creating glob's is expensive.
return files.some(f => patterns.some(pattern => getOrCreateGlob(pattern).match(f)));
}
};
/**
* Converts a given condition to a function that accepts a set of files. The returned
* function can be called to check if the set of files matches the condition.
*/
export function convertConditionToFunction(expr: string): (files: string[]) => boolean {
// Creates a dynamic function with the specified expression. The first parameter will
// be `files` as that corresponds to the supported `files` variable that can be accessed
// in PullApprove condition expressions. The followed parameters correspond to other
// context variables provided by PullApprove for conditions.
const evaluateFn = new Function('files', ...Object.keys(conditionContext), `
return (${transformExpressionToJs(expr)});
`);
// Create a function that calls the dynamically constructed function which mimics
// the condition expression that is usually evaluated with Python in PullApprove.
return files => {
const result = evaluateFn(new PullApproveArray(...files), ...Object.values(conditionContext));
// If an array is returned, we consider the condition as active if the array is not
// empty. This matches PullApprove's condition evaluation that is based on Python.
if (Array.isArray(result)) {
return result.length !== 0;
}
return !!result;
};
}
/**
* Transforms a condition expression from PullApprove that is based on python
* so that it can be run inside JavaScript. Current transformations:
* 1. `not <..>` -> `!<..>`
*/
function transformExpressionToJs(expression: string): string {
return expression.replace(/not\s+/g, '!');
}
/**
* Superset of a native array. The superset provides methods which mimic the
* list data structure used in PullApprove for files in conditions.
*/
class PullApproveArray extends Array<string> {
constructor(...elements: string[]) {
super(...elements);
// Set the prototype explicitly because in ES5, the prototype is accidentally
// lost due to a limitation in down-leveling.
// https://github.com/Microsoft/TypeScript/wiki/FAQ#why-doesnt-extending-built-ins-like-error-array-and-map-work.
Object.setPrototypeOf(this, PullApproveArray.prototype);
}
/** Returns a new array which only includes files that match the given pattern. */
include(pattern: string): PullApproveArray {
return new PullApproveArray(...this.filter(s => getOrCreateGlob(pattern).match(s)));
}
/** Returns a new array which only includes files that did not match the given pattern. */
exclude(pattern: string): PullApproveArray {
return new PullApproveArray(...this.filter(s => !getOrCreateGlob(pattern).match(s)));
}
}
/**
* Gets a glob for the given pattern. The cached glob will be returned
* if available. Otherwise a new glob will be created and cached.
*/
function getOrCreateGlob(pattern: string) {
if (patternCache.has(pattern)) {
return patternCache.get(pattern)!;
}
const glob = new Minimatch(pattern, {dot: true});
patternCache.set(pattern, glob);
return glob;
}