src/index.js

   1 'use strict'
   2
   3 const debug = require('debug')('purs-loader')
   4 const loaderUtils = require('loader-utils')
   5 const Promise = require('bluebird')
   6 const fs = Promise.promisifyAll(require('fs'))
   7 const path = require('path')
   8 const jsStringEscape = require('js-string-escape')
   9 const PsModuleMap = require('./PsModuleMap');
  10 const Psc = require('./Psc');
  11 const PscIde = require('./PscIde');
  12 const dargs = require('./dargs');
  13
  14 const requireRegex = /require\(['"]\.\.\/([\w\.]+)['"]\)/g
  15
  16 module.exports = function purescriptLoader(source, map) {
  17   const callback = this.async()
  18   const config = this.options
  19   const query = loaderUtils.parseQuery(this.query)
  20   const webpackOptions = this.options.purescriptLoader || {}
  21
  22   const options = Object.assign({
  23     context: config.context,
  24     psc: 'psc',
  25     pscArgs: {},
  26     pscBundle: 'psc-bundle',
  27     pscBundleArgs: {},
  28     pscIde: false,
  29     pscIdeColors: webpackOptions.psc === 'psa' || query.psc === 'psa',
  30     pscIdeArgs: {},
  31     bundleOutput: 'output/bundle.js',
  32     bundleNamespace: 'PS',
  33     bundle: false,
  34     warnings: true,
  35     output: 'output',
  36     src: [
  37       path.join('src', '**', '*.purs'),
  38       path.join('bower_components', 'purescript-*', 'src', '**', '*.purs')
  39     ]
  40   }, webpackOptions, query)
  41
  42   this.cacheable && this.cacheable()
  43
  44   let cache = config.purescriptLoaderCache = config.purescriptLoaderCache || {
  45     rebuild: false,
  46     deferred: [],
  47     bundleModules: []
  48   }
  49
  50   if (!config.purescriptLoaderInstalled) {
  51     config.purescriptLoaderInstalled = true
  52
  53     // invalidate loader cache when bundle is marked as invalid (in watch mode)
  54     this._compiler.plugin('invalid', () => {
  55       debug('invalidating loader cache');
  56
  57       cache = config.purescriptLoaderCache = {
  58         rebuild: options.pscIde,
  59         deferred: [],
  60         bundleModules: [],
  61         ideServer: cache.ideServer,
  62         psModuleMap: cache.psModuleMap
  63       }
  64     })
  65   }
  66
  67   const psModuleName = PsModuleMap.match(source)
  68   const psModule = {
  69     name: psModuleName,
  70     load: js => callback(null, js),
  71     reject: error => callback(error),
  72     srcPath: this.resourcePath,
  73     srcDir: path.dirname(this.resourcePath),
  74     jsPath: path.resolve(path.join(options.output, psModuleName, 'index.js')),
  75     options: options,
  76     cache: cache,
  77     emitWarning: warning => this.emitWarning(warning),
  78     emitError: error => this.emitError(error)
  79   }
  80
  81   debug('loader called', psModule.name)
  82
  83   if (options.bundle) {
  84     cache.bundleModules.push(psModule.name)
  85   }
  86
  87   if (cache.rebuild) {
  88     return PscIde.connect(psModule)
  89       .then(PscIde.rebuild)
  90       .then(toJavaScript)
  91       .then(psModule.load)
  92       .catch(psModule.reject)
  93   }
  94
  95   if (cache.compilationFinished) {
  96     return toJavaScript(psModule).then(psModule.load).catch(psModule.reject)
  97   }
  98
  99   // We need to wait for compilation to finish before the loaders run so that
 100   // references to compiled output are valid.
 101   cache.deferred.push(psModule)
 102
 103   if (!cache.compilationStarted) {
 104     return Psc.compile(psModule)
 105        .then(() => PsModuleMap.makeMap(options.src).then(map => {
 106          debug('rebuilt module map');
 107          cache.psModuleMap = map;
 108        }))
 109       .then(() => Promise.map(cache.deferred, psModule => {
 110         if (typeof cache.ideServer === 'object') cache.ideServer.kill()
 111         return toJavaScript(psModule).then(psModule.load)
 112       }))
 113       .catch(error => {
 114         cache.deferred[0].reject(error)
 115         cache.deferred.slice(1).forEach(psModule => psModule.reject(new Error('purs-loader failed')))
 116       })
 117   }
 118 }
 119
 120 function updatePsModuleMap(psModule) {
 121   const options = psModule.options
 122   const cache = psModule.cache
 123   const filePurs = psModule.srcPath
 124   if (!cache.psModuleMap) {
 125     debug('module mapping does not exist');
 126     return PsModuleMap.makeMap(options.src).then(map => {
 127       cache.psModuleMap = map;
 128       return cache.psModuleMap;
 129     });
 130   }
 131   else {
 132     return PsModuleMap.makeMapEntry(filePurs).then(result => {
 133       const map = Object.assign(cache.psModuleMap, result)
 134       cache.psModuleMap = map;
 135       return cache.psModuleMap;
 136     });
 137   }
 138 }
 139
 140 // The actual loader is executed *after* purescript compilation.
 141 function toJavaScript(psModule) {
 142   const options = psModule.options
 143   const cache = psModule.cache
 144   const bundlePath = path.resolve(options.bundleOutput)
 145   const jsPath = cache.bundle ? bundlePath : psModule.jsPath
 146
 147   debug('loading JavaScript for', psModule.name)
 148
 149   return Promise.props({
 150     js: fs.readFileAsync(jsPath, 'utf8'),
 151     psModuleMap: updatePsModuleMap(psModule)
 152   }).then(result => {
 153     let js = ''
 154
 155     if (options.bundle) {
 156       // if bundling, return a reference to the bundle
 157       js = 'module.exports = require("'
 158              + jsStringEscape(path.relative(psModule.srcDir, options.bundleOutput))
 159              + '")["' + psModule.name + '"]'
 160     } else {
 161       // replace require paths to output files generated by psc with paths
 162       // to purescript sources, which are then also run through this loader.
 163       js = result.js
 164         .replace(requireRegex, (m, p1) => {
 165           return 'require("' + jsStringEscape(result.psModuleMap[p1].src) + '")'
 166         })
 167         .replace(/require\(['"]\.\/foreign['"]\)/g, (m, p1) => {
 168           return 'require("' + jsStringEscape(result.psModuleMap[psModule.name].ffi) + '")'
 169         })
 170     }
 171
 172     return js
 173   })
 174 }