Refactor to compile independently of purescript-webpack-plugin.

- Remove dependence on purescript-webpack-plugin
- Fixes double-compilation issue by loading compiled JS instead of adding
  dependency.
- Uses `psc-ide-server` for fast rebuilds.

1 files changed, 465 insertions, 0 deletions

diff --git a/src/index.js b/src/index.js
new file mode 100644
index 0000000..0a25ccd
--- /dev/null
+++ b/src/index.js
@@ -0,0 +1,465 @@
+'use strict'
+
+const colors = require('chalk')
+const debug = require('debug')('purs-loader')
+const loaderUtils = require('loader-utils')
+const globby = require('globby')
+const Promise = require('bluebird')
+const fs = Promise.promisifyAll(require('fs'))
+const spawn = require('child_process').spawn
+const path = require('path')
+const retryPromise = require('promise-retry')
+
+const psModuleRegex = /(?:^|\n)module\s+([\w\.]+)/i
+const requireRegex = /require\(['"]\.\.\/([\w\.]+)['"]\)/g
+
+module.exports = function purescriptLoader(source, map) {
+  const callback = this.async()
+  const config = this.options
+  const query = loaderUtils.parseQuery(this.query)
+  const webpackOptions = this.options.purescriptLoader || {}
+
+  const options = Object.assign({
+    context: config.context,
+    psc: 'psc',
+    pscArgs: {},
+    pscBundle: 'psc-bundle',
+    pscBundleArgs: {},
+    pscIdeColors: webpackOptions.psc === 'psa' || query.psc === 'psa',
+    pscIdeArgs: {},
+    bundleOutput: 'output/bundle.js',
+    bundleNamespace: 'PS',
+    bundle: false,
+    warnings: true,
+    output: 'output',
+    src: [
+      path.join('src', '**', '*.purs'),
+      path.join('bower_components', 'purescript-*', 'src', '**', '*.purs')
+    ],
+    ffi: [
+      path.join('src', '**', '*.js'),
+      path.join('bower_components', 'purescript-*', 'src', '**', '*.js')
+    ],
+  }, webpackOptions, query)
+
+  this.cacheable && this.cacheable()
+
+  let cache = config.purescriptLoaderCache = config.purescriptLoaderCache || {
+    rebuild: false,
+    deferred: [],
+    bundleModules: [],
+  }
+
+  if (!config.purescriptLoaderInstalled) {
+    config.purescriptLoaderInstalled = true
+
+    // invalidate loader cache when bundle is marked as invalid (in watch mode)
+    this._compiler.plugin('invalid', () => {
+      cache = config.purescriptLoaderCache = {
+        rebuild: true,
+        deferred: [],
+        ideServer: cache.ideServer
+      }
+    })
+
+    // add psc warnings to webpack compilation warnings
+    this._compiler.plugin('after-compile', (compilation, callback) => {
+      if (options.warnings && cache.warnings && cache.warnings.length) {
+        compilation.warnings.unshift(`PureScript compilation:\n${cache.warnings.join('')}`)
+      }
+
+      if (cache.errors && cache.errors.length) {
+        compilation.errors.unshift(`PureScript compilation:\n${cache.errors.join('\n')}`)
+      }
+
+      callback()
+    })
+  }
+
+  const psModuleName = match(psModuleRegex, source)
+  const psModule = {
+    name: psModuleName,
+    load: js => callback(null, js),
+    reject: error => callback(error),
+    srcPath: this.resourcePath,
+    srcDir: path.dirname(this.resourcePath),
+    jsPath: path.resolve(path.join(options.output, psModuleName, 'index.js')),
+    options: options,
+    cache: cache,
+  }
+
+  if (options.bundle) {
+    cache.bundleModules.push(psModule.name)
+  }
+
+  if (cache.rebuild) {
+    return connectIdeServer(psModule)
+      .then(rebuild)
+      .then(toJavaScript)
+      .then(psModule.load)
+      .catch(psModule.reject)
+  }
+
+  if (cache.compilation && cache.compilation.length) {
+    return toJavaScript(psModule).then(psModule.load).catch(psModule.reject)
+  }
+
+  // We need to wait for compilation to finish before the loaders run so that
+  // references to compiled output are valid.
+  cache.deferred.push(psModule)
+
+  if (!cache.compilation) {
+    return compile(psModule)
+      .then(() => Promise.map(cache.deferred, psModule => {
+        if (typeof cache.ideServer === 'object') cache.ideServer.kill()
+        return toJavaScript(psModule).then(psModule.load)
+      }))
+      .catch(error => {
+        cache.deferred[0].reject(error)
+        cache.deferred.slice(1).forEach(psModule => psModule.reject(true))
+      })
+  }
+}
+
+// The actual loader is executed *after* purescript compilation.
+function toJavaScript(psModule) {
+  const options = psModule.options
+  const cache = psModule.cache
+  const bundlePath = path.resolve(options.bundleOutput)
+  const jsPath = cache.bundle ? bundlePath : psModule.jsPath
+
+  debug('loading JavaScript for', psModule.srcPath)
+
+  return Promise.props({
+    js: fs.readFileAsync(jsPath, 'utf8'),
+    psModuleMap: psModuleMap(options.src, cache)
+  }).then(result => {
+    let js = ''
+
+    if (options.bundle) {
+      // if bundling, return a reference to the bundle
+      js = 'module.exports = require("'
+             + path.relative(psModule.srcDir, options.bundleOutput)
+             + '")["' + psModule.name + '"]'
+    } else {
+      // replace require paths to output files generated by psc with paths
+      // to purescript sources, which are then also run through this loader.
+      const foreignRequire = 'require("' + path.resolve(
+        path.join(psModule.options.output, psModule.name, 'foreign.js')
+      ) + '")'
+
+      js = result.js
+        .replace(requireRegex, (m, p1) => {
+          return 'require("' + result.psModuleMap[p1] + '")'
+        })
+        .replace(/require\(['"]\.\/foreign['"]\)/g, foreignRequire)
+    }
+
+    return js
+  })
+}
+
+function compile(psModule) {
+  const options = psModule.options
+  const cache = psModule.cache
+  const stderr = []
+
+  if (cache.compilation) return Promise.resolve(cache.compilation)
+
+  cache.compilation = []
+  cache.warnings = []
+  cache.errors = []
+
+
+  const args = dargs(Object.assign({
+    _: options.src,
+    ffi: options.ffi,
+    output: options.output,
+  }, options.pscArgs))
+
+  debug('spawning compiler %s %o', options.psc, args)
+
+  return (new Promise((resolve, reject) => {
+    console.log('\nCompiling PureScript...')
+
+    const compilation = spawn(options.psc, args)
+
+    compilation.stderr.on('data', data => stderr.push(data.toString()))
+
+    compilation.on('close', code => {
+      console.log('Finished compiling PureScript.')
+      if (code !== 0) {
+        cache.compilation = cache.errors = stderr
+        reject(true)
+      } else {
+        cache.compilation = cache.warnings = stderr
+        resolve(psModule)
+      }
+    })
+  }))
+  .then(compilerOutput => {
+    if (options.bundle) {
+      return bundle(options, cache).then(() => psModule)
+    }
+    return psModule
+  })
+}
+
+function rebuild(psModule) {
+  const options = psModule.options
+  const cache = psModule.cache
+
+  debug('attempting rebuild with psc-ide-client %s', psModule.srcPath)
+
+  const request = (body) => new Promise((resolve, reject) => {
+    const args = dargs(options.pscIdeArgs)
+    const ideClient = spawn('psc-ide-client', args)
+
+    ideClient.stdout.once('data', data => {
+      const res = JSON.parse(data.toString())
+      debug(res)
+
+      if (!Array.isArray(res.result)) {
+        return res.resultType === 'success'
+               ? resolve(psModule)
+               : reject(res.result)
+      }
+
+      Promise.map(res.result, (item, i) => {
+        debug(item)
+        return formatIdeResult(item, options, i, res.result.length)
+      })
+      .then(compileMessages => {
+        if (res.resultType === 'error') {
+          cache.errors = compileMessages
+          reject(res.result)
+        } else {
+          cache.warnings = compileMessages
+          resolve(psModule)
+        }
+      })
+    })
+
+    ideClient.stderr.once('data', data => reject(data.toString()))
+
+    ideClient.stdin.write(JSON.stringify(body))
+    ideClient.stdin.write('\n')
+  })
+
+  return request({
+    command: 'rebuild',
+    params: {
+      file: psModule.srcPath,
+    }
+  }).catch(res => {
+    if (res.resultType === 'error') {
+      if (res.result.some(item => item.errorCode === 'UnknownModule')) {
+        console.log('Unknown module, attempting full recompile')
+        return compile(psModule).then(() => request({ command: 'load' }))
+      }
+    }
+    return Promise.resolve(psModule)
+  })
+}
+
+function formatIdeResult(result, options, index, length) {
+  const srcPath = path.relative(options.context, result.filename)
+  const pos = result.position
+  const fileAndPos = `${srcPath}:${pos.startLine}:${pos.startColumn}`
+  let numAndErr = `[${index+1}/${length} ${result.errorCode}]`
+  numAndErr = options.pscIdeColors ? colors.yellow(numAndErr) : numAndErr
+
+  return fs.readFileAsync(result.filename, 'utf8').then(source => {
+    const lines = source.split('\n').slice(pos.startLine - 1, pos.endLine)
+    const endsOnNewline = pos.endColumn === 1 && pos.startLine !== pos.endLine
+    const up = options.pscIdeColors ? colors.red('^') : '^'
+    const down = options.pscIdeColors ? colors.red('v') : 'v'
+    let trimmed = lines.slice(0)
+
+    if (endsOnNewline) {
+      lines.splice(lines.length - 1, 1)
+      pos.endLine = pos.endLine - 1
+      pos.endColumn = lines[lines.length - 1].length || 1
+    }
+
+    // strip newlines at the end
+    if (endsOnNewline) {
+      trimmed = lines.reverse().reduce((trimmed, line, i) => {
+        if (i === 0 && line === '') trimmed.trimming = true
+        if (!trimmed.trimming) trimmed.push(line)
+        if (trimmed.trimming && line !== '') {
+          trimmed.trimming = false
+          trimmed.push(line)
+        }
+        return trimmed
+      }, []).reverse()
+      pos.endLine = pos.endLine - (lines.length - trimmed.length)
+      pos.endColumn = trimmed[trimmed.length - 1].length || 1
+    }
+
+    const spaces = ' '.repeat(String(pos.endLine).length)
+    let snippet = trimmed.map((line, i) => {
+      return `  ${pos.startLine + i}  ${line}`
+    }).join('\n')
+
+    if (trimmed.length === 1) {
+      snippet += `\n  ${spaces}  ${' '.repeat(pos.startColumn - 1)}${up.repeat(pos.endColumn - pos.startColumn + 1)}`
+    } else {
+      snippet = `  ${spaces}  ${' '.repeat(pos.startColumn - 1)}${down}\n${snippet}`
+      snippet += `\n  ${spaces}  ${' '.repeat(pos.endColumn - 1)}${up}`
+    }
+
+    return Promise.resolve(
+      `\n${numAndErr} ${fileAndPos}\n\n${snippet}\n\n${result.message}`
+    )
+  })
+}
+
+function bundle(options, cache) {
+  if (cache.bundle) return Promise.resolve(cache.bundle)
+
+  const stdout = []
+  const stderr = cache.bundle = []
+
+  const args = dargs(Object.assign({
+    _: [path.join(options.output, '*', '*.js')],
+    output: options.bundleOutput,
+    namespace: options.bundleNamespace,
+  }, options.pscBundleArgs))
+
+  cache.bundleModules.forEach(name => args.push('--module', name))
+
+  debug('spawning bundler %s %o', options.pscBundle, args.join(' '))
+
+  return (new Promise((resolve, reject) => {
+    console.log('Bundling PureScript...')
+
+    const compilation = spawn(options.pscBundle, args)
+
+    compilation.stdout.on('data', data => stdout.push(data.toString()))
+    compilation.stderr.on('data', data => stderr.push(data.toString()))
+    compilation.on('close', code => {
+      if (code !== 0) {
+        cache.errors.concat(stderr)
+        return reject(true)
+      }
+      cache.bundle = stderr
+      resolve(fs.appendFileAsync('output/bundle.js', `module.exports = ${options.bundleNamespace}`))
+    })
+  }))
+}
+
+// map of PS module names to their source path
+function psModuleMap(globs, cache) {
+  if (cache.psModuleMap) return Promise.resolve(cache.psModuleMap)
+
+  return globby(globs).then(paths => {
+    return Promise
+      .props(paths.reduce((map, file) => {
+        map[file] = fs.readFileAsync(file, 'utf8')
+        return map
+      }, {}))
+      .then(srcMap => {
+        cache.psModuleMap = Object.keys(srcMap).reduce((map, file) => {
+          const source = srcMap[file]
+          const psModuleName = match(psModuleRegex, source)
+          map[psModuleName] = path.resolve(file)
+          return map
+        }, {})
+        return cache.psModuleMap
+      })
+  })
+}
+
+function connectIdeServer(psModule) {
+  const options = psModule.options
+  const cache = psModule.cache
+
+  if (cache.ideServer) return Promise.resolve(psModule)
+
+  cache.ideServer = true
+
+  const connect = () => new Promise((resolve, reject) => {
+    const args = dargs(options.pscIdeArgs)
+
+    debug('attempting to connect to psc-ide-server', args)
+
+    const ideClient = spawn('psc-ide-client', args)
+
+    ideClient.stderr.on('data', data => {
+      debug(data.toString())
+      cache.ideServer = false
+      reject(true)
+    })
+    ideClient.stdout.once('data', data => {
+      debug(data.toString())
+      if (data.toString()[0] === '{') {
+        const res = JSON.parse(data.toString())
+        if (res.resultType === 'success') {
+          cache.ideServer = ideServer
+          resolve(psModule)
+        } else {
+          cache.ideServer = ideServer
+          reject(true)
+        }
+      } else {
+        cache.ideServer = false
+        reject(true)
+      }
+    })
+    ideClient.stdin.resume()
+    ideClient.stdin.write(JSON.stringify({ command: 'load' }))
+    ideClient.stdin.write('\n')
+  })
+
+  const args = dargs(Object.assign({
+    outputDirectory: options.output,
+  }, options.pscIdeArgs))
+
+  debug('attempting to start psc-ide-server', args)
+
+  const ideServer = cache.ideServer = spawn('psc-ide-server', [])
+  ideServer.stderr.on('data', data => {
+    debug(data.toString())
+  })
+
+  return retryPromise((retry, number) => {
+    return connect().catch(error => {
+      if (!cache.ideServer && number === 9) {
+        debug(error)
+
+        console.log(
+          'failed to connect to or start psc-ide-server, ' +
+          'full compilation will occur on rebuild'
+        )
+
+        return Promise.resolve(psModule)
+      }
+
+      return retry(error)
+    })
+  }, {
+    retries: 9,
+    factor: 1,
+    minTimeout: 333,
+    maxTimeout: 333,
+  })
+}
+
+function match(regex, str) {
+  const matches = str.match(regex)
+  return matches && matches[1]
+}
+
+function dargs(obj) {
+  return Object.keys(obj).reduce((args, key) => {
+    const arg = '--' + key.replace(/[A-Z]/g, '-$&').toLowerCase();
+    const val = obj[key]
+
+    if (key === '_') val.forEach(v => args.push(v))
+    else if (Array.isArray(val)) val.forEach(v => args.push(arg, v))
+    else args.push(arg, obj[key])
+
+    return args
+  }, [])
+}