feat(fs): add first draft of fs-overrider

LICENSE

@@ -11,3 +11,29 @@ ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+=======
+
+lib/fs.js is derived from the ElectronJS lib/common/asar.js
+module. Electron has the following license:
+
+Copyright (c) 2013-2018 GitHub Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

lib/fs.js

@@ -0,0 +1,367 @@
+// NOTE: This is largely taken from Atom's `asar` patch here: https://raw.githubusercontent.com/electron/electron/master/lib/common/asar.js
+
+const childProcess = require('child_process')
+const pkgmap = require('./pkgmap.js')
+const util = require('util')
+
+// Create a ENOENT error.
+function notFoundError (filePath, callback) {
+  const error = new Error(`ENOENT, ${filePath} not found`)
+  error.code = 'ENOENT'
+  error.errno = -2
+  if (typeof callback !== 'function') {
+    throw error
+  }
+  process.nextTick(() => callback(error))
+}
+
+// Create a ENOTDIR error.
+function notDirError (callback) {
+  const error = new Error('ENOTDIR, not a directory')
+  error.code = 'ENOTDIR'
+  error.errno = -20
+  if (typeof callback !== 'function') {
+    throw error
+  }
+  process.nextTick(() => callback(error))
+}
+
+// Override APIs that rely on passing file path instead of content to C++.
+function overrideAPISync (module, name, arg) {
+  if (arg == null) {
+    arg = 0
+  }
+  const old = module[name]
+  module[name] = function () {
+    const p = arguments[arg]
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return old.apply(this, arguments) }
+
+    const stat = pkgmap.statSync(resolved, true)
+    if (!stat) {
+      notFoundError(p)
+    }
+
+    arguments[arg] = stat.cachePath
+    return old.apply(this, arguments)
+  }
+}
+
+const overrideAPI = function (module, name, arg) {
+  if (arg == null) {
+    arg = 0
+  }
+  const old = module[name]
+  module[name] = function () {
+    const p = arguments[arg]
+
+    const callback = arguments[arguments.length - 1]
+    if (typeof callback !== 'function') {
+      return overrideAPISync(module, name, arg)
+    }
+
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return old.apply(this, arguments) }
+
+    const stat = pkgmap.statSync(resolved, true)
+    if (!stat) {
+      notFoundError(p, callback)
+    }
+
+    arguments[arg] = stat.cachePath
+    return old.apply(this, arguments)
+  }
+  if (old[util.promisify.custom]) {
+    module[name][util.promisify.custom] = async function () {
+      const p = arguments[arg]
+      const resolved = pkgmap.resolve(p)
+      if (!resolved) {
+        return old[util.promisify.custom].apply(this, arguments)
+      }
+
+      const stat = await pkgmap.stat(resolved, true)
+      if (!stat) {
+        notFoundError(p)
+      }
+
+      arguments[arg] = stat.cachePath
+      return old[util.promisify.custom].apply(this, arguments)
+    }
+  }
+}
+
+// Override fs APIs.
+module.exports.overrideNode = overrideNode
+function overrideNode (fs) {
+  const {lstatSync} = fs
+  fs.lstatSync = function (p) {
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return lstatSync(p) }
+    const stats = pkgmap.statSync(resolved)
+    if (!stats) {
+      notFoundError(p)
+    }
+    return stats
+  }
+
+  const {lstat} = fs
+  fs.lstat = function (p, callback) {
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return lstat(p, callback) }
+    pkgmap.stat(resolved).then(stat => {
+      if (!stat) {
+        notFoundError(p, callback)
+      }
+      callback(null, stat)
+    }, callback)
+  }
+
+  const {statSync} = fs
+  fs.statSync = function (p) {
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return statSync(p) }
+    return fs.lstatSync(p)
+  }
+
+  const {stat} = fs
+  fs.stat = function (p, callback) {
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return stat(p, callback) }
+    return fs.lstat(p, callback)
+  }
+
+  const {statSyncNoException} = fs
+  fs.statSyncNoException = function (p) {
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return statSyncNoException(p) }
+    const stats = pkgmap.statSync(resolved)
+    if (!stats) {
+      return false
+    }
+    return stats
+  }
+
+  const {realpathSync} = fs
+  fs.realpathSync = function (p) {
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return realpathSync.apply(this, arguments) }
+    const stat = fs.lstatSync(p)
+    return fs.realpathSync(stat.cachePath)
+  }
+
+  const {realpath} = fs
+  fs.realpath = function (p, cache, callback) {
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return realpath.apply(this, arguments) }
+    if (typeof cache === 'function') {
+      callback = cache
+      cache = void 0
+    }
+
+    pkgmap.stat(resolved).then(stat => {
+      if (!stat) {
+        notFoundError(p, callback)
+      }
+    }, callback)
+    fs.realpath(stat.cachePath, callback)
+  }
+
+  const {exists} = fs
+  fs.exists = function (p, callback) {
+    const resolved = pkgmap.resolve(p)
+    // pkgmap.resolve distinguishes returns null if no valid pkgmap was found,
+    // and false if a map was found, but the file was not in it.
+    if (resolved == null) { return exists(p, callback) }
+    if (!resolved) { return process.nextTick(() => callback(null, false)) }
+    pkgmap.stat(resolved).then(stat => {
+      callback(null, !!stat)
+    }, callback)
+  }
+
+  fs.exists[util.promisify.custom] = async function (p) {
+    const resolved = pkgmap.resolve(p)
+    // pkgmap.resolve distinguishes returns null if no valid pkgmap was found,
+    // and false if a map was found, but the file was not in it.
+    if (resolved == null) { return exists[util.promisify.custom](p) }
+    return resolved && !!await pkgmap.stat(resolved)
+  }
+
+  const {existsSync} = fs
+  fs.existsSync = function (p) {
+    const resolved = pkgmap.resolve(p)
+    // pkgmap.resolve distinguishes returns null if no valid pkgmap was found,
+    // and false if a map was found, but the file was not in it.
+    if (resolved == null) { return existsSync(p) }
+    return resolved && !!pkgmap.statSync(resolved)
+  }
+
+  const {access} = fs
+  fs.access = function (p, mode, callback) {
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return access(p, mode, callback) }
+    if (typeof mode === 'function') {
+      callback = mode
+      mode = fs.constants.F_OK
+    }
+    pkgmap.stat(resolved).then(stat => {
+      if (!stat) {
+        notFoundError(p, callback)
+      }
+      access(stat.cachePath, mode, callback)
+    }, callback)
+  }
+
+  const {accessSync} = fs
+  fs.accessSync = function (p, mode) {
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return accessSync(p, mode) }
+    if (mode == null) {
+      mode = fs.constants.F_OK
+    }
+    const stat = pkgmap.statSync(resolved)
+    if (!stat) {
+      notFoundError(p)
+    }
+    return fs.accessSync(stat.cachePath, mode)
+  }
+
+  const {readFile} = fs
+  fs.readFile = function (p, options, callback) {
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return readFile(p, options, callback) }
+    if (typeof options === 'function') {
+      callback = options
+      options = {
+        encoding: null
+      }
+    } else if (typeof options === 'string') {
+      options = {
+        encoding: options
+      }
+    } else if (options === null || options === undefined) {
+      options = {
+        encoding: null
+      }
+    } else if (typeof options !== 'object') {
+      throw new TypeError('badarg')
+    }
+    const {encoding} = options
+    pkgmap.read(resolved).then(data => {
+      if (encoding) {
+        data = data.toString(encoding)
+      }
+      callback(null, data)
+    }, callback)
+  }
+
+  const {readFileSync} = fs
+  fs.readFileSync = function (p, options) {
+    const resolved = pkgmap.resolve(p)
+    if (resolved == null) { return readFileSync(p, options) }
+    if (!resolved) {
+      notFoundError(p)
+    }
+    if (!options) {
+      options = {
+        encoding: null
+      }
+    } else if (typeof options === 'string') {
+      options = {
+        encoding: options
+      }
+    } else if (typeof options !== 'object') {
+      throw new TypeError('Bad arguments')
+    }
+    const {encoding} = options
+    const data = pkgmap.readSync(resolved)
+    if (encoding) {
+      return data.toString(encoding)
+    } else {
+      return data
+    }
+  }
+
+  const {readdir} = fs
+  fs.readdir = function (p, callback) {
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return readdir(p, callback) }
+    process.nextTick(function () {
+      callback(new Error('not implemented yet'))
+    })
+  }
+
+  const {readdirSync} = fs
+  fs.readdirSync = function (p) {
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return readdirSync(p) }
+    throw new Error('not implemented yet')
+  }
+
+  const {internalModuleReadJSON} = process.binding('fs')
+  process.binding('fs').internalModuleReadJSON = function (p) {
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return internalModuleReadJSON(p) }
+    try {
+      return pkgmap.readSync(resolved).toString('utf8')
+    } catch (err) {
+    }
+  }
+
+  const {internalModuleStat} = process.binding('fs')
+  process.binding('fs').internalModuleStat = function (p) {
+    const resolved = pkgmap.resolve(p)
+    if (!resolved) { return internalModuleStat(p) }
+    // ENOENT: 34
+    // isDirectory: 1
+    // isFile: 0
+    return -34 // not implemented yet
+  }
+
+  // Calling mkdir for directory inside asar archive should throw ENOTDIR
+  // error, but on Windows it throws ENOENT.
+  // This is to work around the recursive looping bug of mkdirp since it is
+  // widely used.
+  if (process.platform === 'win32') {
+    const {mkdir} = fs
+    fs.mkdir = function (p, mode, callback) {
+      const resolved = pkgmap.resolve(p)
+      if (!resolved) { return mkdir(p, mode, callback) }
+      if (typeof mode === 'function') {
+        callback = mode
+      }
+      return notDirError(callback)
+    }
+
+    const {mkdirSync} = fs
+    fs.mkdirSync = function (p, mode) {
+      const resolved = pkgmap.resolve(p)
+      if (!resolved) { return mkdirSync(p, mode) }
+      notDirError()
+    }
+  }
+
+  // TODO: use spawn-wrap to cover childProcess bits?
+  // const {exec, execSync} = childProcess
+  // childProcess.exec = invokeWithNoAsar(exec)
+  // childProcess.exec[util.promisify.custom] = invokeWithNoAsar(exec[util.promisify.custom])
+  // childProcess.execSync = invokeWithNoAsar(execSync)
+  //
+  // function invokeWithNo (func) {
+  //   return function () {
+  //     const processNoAsarOriginalValue = process.noAsar
+  //     process.noAsar = true
+  //     try {
+  //       return func.apply(this, arguments)
+  //     } finally {
+  //       process.noAsar = processNoAsarOriginalValue
+  //     }
+  //   }
+  // }
+
+  overrideAPI(fs, 'open')
+  // overrideAPI(childProcess, 'execFile')
+  overrideAPISync(process, 'dlopen', 1)
+  overrideAPISync(require('module')._extensions, '.node', 1)
+  overrideAPISync(fs, 'openSync')
+  overrideAPISync(childProcess, 'execFileSync')
+}