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port babel loader fs cache as the default caching engine
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+250
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‎fs-cache.js

+196
Original file line numberDiff line numberDiff line change
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/**
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* Filesystem cache
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*
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* Given a file and a transform function, cache the result into files
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* or retrieve the previously cached files if the given file is already known.
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*
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* @see https://github.com/babel/babel-loader/issues/34
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* @see https://github.com/babel/babel-loader/pull/41
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* @see https://github.com/babel/babel-loader/blob/master/src/fs-cache.js
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*/
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var crypto = require("crypto")
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var mkdirp = require("mkdirp")
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var findCacheDir = require("find-cache-dir")
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var fs = require("fs")
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var os = require("os")
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var path = require("path")
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var zlib = require("zlib")
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var defaultCacheDirectory = null // Lazily instantiated when needed
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/**
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* Read the contents from the compressed file.
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*
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* @async
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* @params {String} filename
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* @params {Function} callback
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*/
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var read = function(filename, callback) {
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return fs.readFile(filename, function(err, data) {
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if (err) {
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return callback(err)
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}
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return zlib.gunzip(data, function(err, content) {
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var result = {}
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if (err) {
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return callback(err)
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}
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try {
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result = JSON.parse(content)
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}
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catch (e) {
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return callback(e)
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}
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return callback(null, result)
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})
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})
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}
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/**
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* Write contents into a compressed file.
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*
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* @async
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* @params {String} filename
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* @params {String} result
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* @params {Function} callback
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*/
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var write = function(filename, result, callback) {
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var content = JSON.stringify(result)
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return zlib.gzip(content, function(err, data) {
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if (err) {
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return callback(err)
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}
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return fs.writeFile(filename, data, callback)
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})
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}
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/**
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* Build the filename for the cached file
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*
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* @params {String} source File source code
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* @params {Object} options Options used
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*
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* @return {String}
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*/
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var filename = function(source, identifier, options) {
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var hash = crypto.createHash("SHA1")
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var contents = JSON.stringify({
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source: source,
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options: options,
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identifier: identifier,
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})
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hash.end(contents)
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return hash.read().toString("hex") + ".json.gz"
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}
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/**
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* Handle the cache
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*
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* @params {String} directory
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* @params {Object} params
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* @params {Function} callback
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*/
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var handleCache = function(directory, params, callback) {
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var source = params.source
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var options = params.options || {}
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var transform = params.transform
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var identifier = params.identifier
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var shouldFallback = typeof params.directory !== "string" &&
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directory !== os.tmpdir()
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// Make sure the directory exists.
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mkdirp(directory, function(err) {
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// Fallback to tmpdir if node_modules folder not writable
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if (err)
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return shouldFallback
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? handleCache(os.tmpdir(), params, callback)
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: callback(err)
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var file = path.join(directory, filename(source, identifier, options))
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return read(file, function(err, content) {
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var result = {}
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// No errors mean that the file was previously cached
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// we just need to return it
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if (!err) return callback(null, content)
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// Otherwise just transform the file
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// return it to the user asap and write it in cache
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try {
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result = transform(source, options)
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}
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catch (error) {
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return callback(error)
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}
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return write(file, result, function(err) {
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// Fallback to tmpdir if node_modules folder not writable
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if (err)
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return shouldFallback
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? handleCache(os.tmpdir(), params, callback)
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: callback(err)
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callback(null, result)
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})
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})
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})
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}
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/**
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* Retrieve file from cache, or create a new one for future reads
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*
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* @async
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* @param {Object} params
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* @param {String} params.directory Directory to store cached files
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* @param {String} params.identifier Unique identifier to bust cache
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* @param {String} params.source Original contents of the file to be cached
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* @param {Object} params.options Options to be given to the transform fn
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* @param {Function} params.transform Function that will transform the
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* original file and whose result will be
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* cached
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*
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* @param {Function<err, result>} callback
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*
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* @example
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*
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* cache({
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* directory: '.tmp/cache',
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* identifier: 'babel-loader-cachefile',
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* source: *source code from file*,
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* options: {
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* experimental: true,
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* runtime: true
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* },
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* transform: function(source, options) {
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* var content = *do what you need with the source*
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* return content
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* }
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* }, function(err, result) {
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*
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* })
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*/
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module.exports = function(params, callback) {
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var directory
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if (typeof params.directory === "string") {
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directory = params.directory
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}
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else {
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if (defaultCacheDirectory === null) {
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defaultCacheDirectory = findCacheDir({
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name: "eslint-loader",
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}) || os.tmpdir()
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}
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directory = defaultCacheDirectory
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}
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handleCache(directory, params, callback)
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}

‎index.js

+54-81
Original file line numberDiff line numberDiff line change
@@ -1,76 +1,21 @@
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var eslint = require("eslint")
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var assign = require("object-assign")
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var loaderUtils = require("loader-utils")
4-
var crypto = require("crypto")
5-
var fs = require("fs")
6-
var findCacheDir = require("find-cache-dir")
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var objectHash = require("object-hash")
8-
var os = require("os")
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var pkg = require("./package.json")
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var cache = require("./fs-cache")
97

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var engines = {}
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var rules = {}
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var cache = null
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var cachePath = null
149

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/**
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* linter
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* printLinterOutput
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*
18-
* @param {String|Buffer} input JavaScript string
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* @param {Object} eslint.executeOnText return value
1914
* @param {Object} config eslint configuration
2015
* @param {Object} webpack webpack instance
2116
* @return {void}
2217
*/
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function lint(input, config, webpack) {
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var resourcePath = webpack.resourcePath
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var cwd = process.cwd()
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// remove cwd from resource path in case webpack has been started from project
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// root, to allow having relative paths in .eslintignore
29-
if (resourcePath.indexOf(cwd) === 0) {
30-
resourcePath = resourcePath.substr(cwd.length + 1)
31-
}
32-
33-
// get engine
34-
var configHash = objectHash(config)
35-
var engine = engines[configHash]
36-
var rulesHash = rules[configHash]
37-
38-
var res
39-
// If cache is enable and the data are the same as in the cache, just
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// use them
41-
if (config.cache) {
42-
// just get rules hash once per engine for performance reasons
43-
if (!rulesHash) {
44-
rulesHash = objectHash(engine.getConfigForFile(resourcePath))
45-
rules[configHash] = rulesHash
46-
}
47-
var inputMD5 = crypto.createHash("md5").update(input).digest("hex")
48-
if (
49-
cache[resourcePath] &&
50-
cache[resourcePath].hash === inputMD5 &&
51-
cache[resourcePath].rules === rulesHash
52-
) {
53-
res = cache[resourcePath].res
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}
55-
}
56-
57-
// Re-lint the text if the cache off or miss
58-
if (!res) {
59-
res = engine.executeOnText(input, resourcePath, true)
60-
61-
// Save new results in the cache
62-
if (config.cache) {
63-
cache[resourcePath] = {
64-
hash: inputMD5,
65-
rules: rulesHash,
66-
res: res,
67-
}
68-
fs.writeFileSync(cachePath, JSON.stringify(cache))
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}
70-
}
71-
72-
// executeOnText ensure we will have res.results[0] only
73-
18+
function printLinterOutput(res, config, webpack) {
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// skip ignored file warning
7520
if (!(
7621
res.warningCount === 1 &&
@@ -155,45 +100,73 @@ function lint(input, config, webpack) {
155100
* @return {void}
156101
*/
157102
module.exports = function(input, map) {
103+
var webpack = this
158104
var config = assign(
159105
// loader defaults
160106
{
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formatter: require("eslint/lib/formatters/stylish"),
108+
cacheIdentifier: JSON.stringify({
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"eslint-loader": pkg.version,
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"eslint": eslint.version,
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}),
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},
163113
// user defaults
164114
this.options.eslint || {},
165115
// loader query string
166116
loaderUtils.getOptions(this)
167117
)
168-
this.cacheable()
118+
119+
var cacheDirectory = config.cacheDirectory
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var cacheIdentifier = config.cacheIdentifier
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122+
delete config.cacheDirectory
123+
delete config.cacheIdentifier
169124

170125
// Create the engine only once per config
171126
var configHash = objectHash(config)
172127
if (!engines[configHash]) {
173128
engines[configHash] = new eslint.CLIEngine(config)
174129
}
175130

176-
// Read the cached information only once and if enable
177-
if (cache === null) {
178-
if (config.cache) {
179-
var thunk = findCacheDir({
180-
name: "eslint-loader",
181-
thunk: true,
182-
create: true,
183-
})
184-
cachePath = thunk("data.json") || os.tmpdir() + "/data.json"
185-
try {
186-
cache = require(cachePath)
187-
}
188-
catch (e) {
189-
cache = {}
131+
this.cacheable()
132+
133+
var resourcePath = webpack.resourcePath
134+
var cwd = process.cwd()
135+
136+
// remove cwd from resource path in case webpack has been started from project
137+
// root, to allow having relative paths in .eslintignore
138+
if (resourcePath.indexOf(cwd) === 0) {
139+
resourcePath = resourcePath.substr(cwd.length + 1)
140+
}
141+
142+
var engine = engines[configHash]
143+
// return early if cached
144+
if (config.cache) {
145+
var callback = this.async()
146+
return cache({
147+
directory: cacheDirectory,
148+
identifier: cacheIdentifier,
149+
options: config,
150+
transform: function() {
151+
return lint(engine, input, resourcePath)
152+
},
153+
}, function(err, res) {
154+
if (err) {
155+
return callback(err)
190156
}
191-
}
192-
else {
193-
cache = false
194-
}
157+
printLinterOutput(res, config, webpack)
158+
return callback(null, input, map)
159+
})
195160
}
196161

197-
lint(input, config, this)
198-
this.callback(null, input, map)
162+
printLinterOutput(
163+
lint(engine, input, resourcePath),
164+
config,
165+
this
166+
)
167+
this.callback(input, map)
168+
}
169+
170+
function lint(engine, input, resourcePath) {
171+
engine.executeOnText(input, resourcePath, true)
199172
}

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