/**
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* @fileoverview Utility for caching lint results.
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* @author Kevin Partington
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*/
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"use strict";
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//-----------------------------------------------------------------------------
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// Requirements
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//-----------------------------------------------------------------------------
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const assert = require("assert");
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const fs = require("fs");
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const fileEntryCache = require("file-entry-cache");
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const stringify = require("json-stable-stringify-without-jsonify");
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const pkg = require("../../package.json");
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const hash = require("./hash");
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//-----------------------------------------------------------------------------
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// Helpers
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//-----------------------------------------------------------------------------
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const configHashCache = new WeakMap();
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const nodeVersion = process && process.version;
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/**
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* Calculates the hash of the config
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* @param {ConfigArray} config The config.
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* @returns {string} The hash of the config
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*/
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function hashOfConfigFor(config) {
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if (!configHashCache.has(config)) {
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configHashCache.set(config, hash(`${pkg.version}_${nodeVersion}_${stringify(config)}`));
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}
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return configHashCache.get(config);
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}
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//-----------------------------------------------------------------------------
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// Public Interface
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//-----------------------------------------------------------------------------
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/**
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* Lint result cache. This wraps around the file-entry-cache module,
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* transparently removing properties that are difficult or expensive to
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* serialize and adding them back in on retrieval.
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*/
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class LintResultCache {
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/**
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* Creates a new LintResultCache instance.
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* @param {string} cacheFileLocation The cache file location.
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* configuration lookup by file path).
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*/
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constructor(cacheFileLocation) {
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assert(cacheFileLocation, "Cache file location is required");
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this.fileEntryCache = fileEntryCache.create(cacheFileLocation);
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}
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/**
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* Retrieve cached lint results for a given file path, if present in the
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* cache. If the file is present and has not been changed, rebuild any
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* missing result information.
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* @param {string} filePath The file for which to retrieve lint results.
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* @param {ConfigArray} config The config of the file.
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* @returns {Object|null} The rebuilt lint results, or null if the file is
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* changed or not in the filesystem.
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*/
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getCachedLintResults(filePath, config) {
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/*
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* Cached lint results are valid if and only if:
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* 1. The file is present in the filesystem
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* 2. The file has not changed since the time it was previously linted
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* 3. The ESLint configuration has not changed since the time the file
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* was previously linted
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* If any of these are not true, we will not reuse the lint results.
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*/
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const fileDescriptor = this.fileEntryCache.getFileDescriptor(filePath);
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const hashOfConfig = hashOfConfigFor(config);
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const changed = fileDescriptor.changed || fileDescriptor.meta.hashOfConfig !== hashOfConfig;
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if (fileDescriptor.notFound || changed) {
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return null;
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}
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// If source is present but null, need to reread the file from the filesystem.
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if (fileDescriptor.meta.results && fileDescriptor.meta.results.source === null) {
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fileDescriptor.meta.results.source = fs.readFileSync(filePath, "utf-8");
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}
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return fileDescriptor.meta.results;
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}
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/**
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* Set the cached lint results for a given file path, after removing any
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* information that will be both unnecessary and difficult to serialize.
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* Avoids caching results with an "output" property (meaning fixes were
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* applied), to prevent potentially incorrect results if fixes are not
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* written to disk.
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* @param {string} filePath The file for which to set lint results.
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* @param {ConfigArray} config The config of the file.
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* @param {Object} result The lint result to be set for the file.
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* @returns {void}
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*/
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setCachedLintResults(filePath, config, result) {
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if (result && Object.prototype.hasOwnProperty.call(result, "output")) {
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return;
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}
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const fileDescriptor = this.fileEntryCache.getFileDescriptor(filePath);
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if (fileDescriptor && !fileDescriptor.notFound) {
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// Serialize the result, except that we want to remove the file source if present.
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const resultToSerialize = Object.assign({}, result);
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/*
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* Set result.source to null.
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* In `getCachedLintResults`, if source is explicitly null, we will
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* read the file from the filesystem to set the value again.
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*/
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if (Object.prototype.hasOwnProperty.call(resultToSerialize, "source")) {
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resultToSerialize.source = null;
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}
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fileDescriptor.meta.results = resultToSerialize;
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fileDescriptor.meta.hashOfConfig = hashOfConfigFor(config);
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}
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}
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/**
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* Persists the in-memory cache to disk.
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* @returns {void}
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*/
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reconcile() {
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this.fileEntryCache.reconcile();
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}
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}
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module.exports = LintResultCache;
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