electron/lib/common/asar.js

(function () {
  const asar = process.binding('atom_common_asar');
  const child_process = require('child_process');
  const path = require('path');
  const util = require('util');

  var hasProp = {}.hasOwnProperty;

  // Cache asar archive objects.
  var cachedArchives = {};

  var getOrCreateArchive = function(p) {
    var archive;
    archive = cachedArchives[p];
    if (archive != null) {
      return archive;
    }
    archive = asar.createArchive(p);
    if (!archive) {
      return false;
    }
    return cachedArchives[p] = archive;
  };

  // Clean cache on quit.
  process.on('exit', function() {
    var archive, p;
    for (p in cachedArchives) {
      if (!hasProp.call(cachedArchives, p)) continue;
      archive = cachedArchives[p];
      archive.destroy();
    }
  });

  // Separate asar package's path from full path.
  var splitPath = function(p) {
    var index;

    // shortcut to disable asar.
    if (process.noAsar) {
      return [false];
    }

    if (typeof p !== 'string') {
      return [false];
    }
    if (p.substr(-5) === '.asar') {
      return [true, p, ''];
    }
    p = path.normalize(p);
    index = p.lastIndexOf(".asar" + path.sep);
    if (index === -1) {
      return [false];
    }
    return [true, p.substr(0, index + 5), p.substr(index + 6)];
  };

  // Convert asar archive's Stats object to fs's Stats object.
  var nextInode = 0;

  var uid = process.getuid != null ? process.getuid() : 0;

  var gid = process.getgid != null ? process.getgid() : 0;

  var fakeTime = new Date();

  var asarStatsToFsStats = function(stats) {
    return {
      dev: 1,
      ino: ++nextInode,
      mode: 33188,
      nlink: 1,
      uid: uid,
      gid: gid,
      rdev: 0,
      atime: stats.atime || fakeTime,
      birthtime: stats.birthtime || fakeTime,
      mtime: stats.mtime || fakeTime,
      ctime: stats.ctime || fakeTime,
      size: stats.size,
      isFile: function() {
        return stats.isFile;
      },
      isDirectory: function() {
        return stats.isDirectory;
      },
      isSymbolicLink: function() {
        return stats.isLink;
      },
      isBlockDevice: function() {
        return false;
      },
      isCharacterDevice: function() {
        return false;
      },
      isFIFO: function() {
        return false;
      },
      isSocket: function() {
        return false;
      }
    };
  };

  // Create a ENOENT error.
  var notFoundError = function(asarPath, filePath, callback) {
    var error;
    error = new Error("ENOENT, " + filePath + " not found in " + asarPath);
    error.code = "ENOENT";
    error.errno = -2;
    if (typeof callback !== 'function') {
      throw error;
    }
    return process.nextTick(function() {
      return callback(error);
    });
  };

  // Create a ENOTDIR error.
  var notDirError = function(callback) {
    var error;
    error = new Error('ENOTDIR, not a directory');
    error.code = 'ENOTDIR';
    error.errno = -20;
    if (typeof callback !== 'function') {
      throw error;
    }
    return process.nextTick(function() {
      return callback(error);
    });
  };

  // Create invalid archive error.
  var invalidArchiveError = function(asarPath, callback) {
    var error;
    error = new Error("Invalid package " + asarPath);
    if (typeof callback !== 'function') {
      throw error;
    }
    return process.nextTick(function() {
      return callback(error);
    });
  };

  // Override APIs that rely on passing file path instead of content to C++.
  var overrideAPISync = function(module, name, arg) {
    var old;
    if (arg == null) {
      arg = 0;
    }
    old = module[name];
    return module[name] = function() {
      var archive, newPath, p;
      p = arguments[arg];
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return old.apply(this, arguments);
      }
      archive = getOrCreateArchive(asarPath);
      if (!archive) {
        invalidArchiveError(asarPath);
      }
      newPath = archive.copyFileOut(filePath);
      if (!newPath) {
        notFoundError(asarPath, filePath);
      }
      arguments[arg] = newPath;
      return old.apply(this, arguments);
    };
  };

  var overrideAPI = function(module, name, arg) {
    var old;
    if (arg == null) {
      arg = 0;
    }
    old = module[name];
    return module[name] = function() {
      var archive, callback, newPath, p;
      p = arguments[arg];
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return old.apply(this, arguments);
      }
      callback = arguments[arguments.length - 1];
      if (typeof callback !== 'function') {
        return overrideAPISync(module, name, arg);
      }
      archive = getOrCreateArchive(asarPath);
      if (!archive) {
        return invalidArchiveError(asarPath, callback);
      }
      newPath = archive.copyFileOut(filePath);
      if (!newPath) {
        return notFoundError(asarPath, filePath, callback);
      }
      arguments[arg] = newPath;
      return old.apply(this, arguments);
    };
  };

  // Override fs APIs.
  exports.wrapFsWithAsar = function(fs) {
    var exists, existsSync, internalModuleReadFile, internalModuleStat, lstat, lstatSync, mkdir, mkdirSync, readFile, readFileSync, readdir, readdirSync, realpath, realpathSync, stat, statSync, statSyncNoException, logFDs, logASARAccess;

    logFDs = {};
    logASARAccess = function(asarPath, filePath, offset) {
      if (!process.env.ELECTRON_LOG_ASAR_READS) {
        return;
      }
      if (!logFDs[asarPath]) {
        var logFilename, logPath;
        const path = require('path');
        logFilename = path.basename(asarPath, '.asar') + '-access-log.txt';
        logPath = path.join(require('os').tmpdir(), logFilename);
        logFDs[asarPath] = fs.openSync(logPath, 'a');
        console.log('Logging ' + asarPath + ' access to ' + logPath);
      }
      fs.writeSync(logFDs[asarPath], offset + ': ' + filePath + '\n');
    };

    lstatSync = fs.lstatSync;
    fs.lstatSync = function(p) {
      var archive, stats;
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return lstatSync(p);
      }
      archive = getOrCreateArchive(asarPath);
      if (!archive) {
        invalidArchiveError(asarPath);
      }
      stats = archive.stat(filePath);
      if (!stats) {
        notFoundError(asarPath, filePath);
      }
      return asarStatsToFsStats(stats);
    };
    lstat = fs.lstat;
    fs.lstat = function(p, callback) {
      var archive, stats;
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return lstat(p, callback);
      }
      archive = getOrCreateArchive(asarPath);
      if (!archive) {
        return invalidArchiveError(asarPath, callback);
      }
      stats = getOrCreateArchive(asarPath).stat(filePath);
      if (!stats) {
        return notFoundError(asarPath, filePath, callback);
      }
      return process.nextTick(function() {
        return callback(null, asarStatsToFsStats(stats));
      });
    };
    statSync = fs.statSync;
    fs.statSync = function(p) {
      const [isAsar] = splitPath(p);
      if (!isAsar) {
        return statSync(p);
      }

      // Do not distinguish links for now.
      return fs.lstatSync(p);
    };
    stat = fs.stat;
    fs.stat = function(p, callback) {
      const [isAsar] = splitPath(p);
      if (!isAsar) {
        return stat(p, callback);
      }

      // Do not distinguish links for now.
      return process.nextTick(function() {
        return fs.lstat(p, callback);
      });
    };
    statSyncNoException = fs.statSyncNoException;
    fs.statSyncNoException = function(p) {
      var archive, stats;
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return statSyncNoException(p);
      }
      archive = getOrCreateArchive(asarPath);
      if (!archive) {
        return false;
      }
      stats = archive.stat(filePath);
      if (!stats) {
        return false;
      }
      return asarStatsToFsStats(stats);
    };
    realpathSync = fs.realpathSync;
    fs.realpathSync = function(p) {
      var archive, real;
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return realpathSync.apply(this, arguments);
      }
      archive = getOrCreateArchive(asarPath);
      if (!archive) {
        invalidArchiveError(asarPath);
      }
      real = archive.realpath(filePath);
      if (real === false) {
        notFoundError(asarPath, filePath);
      }
      return path.join(realpathSync(asarPath), real);
    };
    realpath = fs.realpath;
    fs.realpath = function(p, cache, callback) {
      var archive, real;
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return realpath.apply(this, arguments);
      }
      if (typeof cache === 'function') {
        callback = cache;
        cache = void 0;
      }
      archive = getOrCreateArchive(asarPath);
      if (!archive) {
        return invalidArchiveError(asarPath, callback);
      }
      real = archive.realpath(filePath);
      if (real === false) {
        return notFoundError(asarPath, filePath, callback);
      }
      return realpath(asarPath, function(err, p) {
        if (err) {
          return callback(err);
        }
        return callback(null, path.join(p, real));
      });
    };
    exists = fs.exists;
    fs.exists = function(p, callback) {
      var archive;
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return exists(p, callback);
      }
      archive = getOrCreateArchive(asarPath);
      if (!archive) {
        return invalidArchiveError(asarPath, callback);
      }
      return process.nextTick(function() {
        return callback(archive.stat(filePath) !== false);
      });
    };
    existsSync = fs.existsSync;
    fs.existsSync = function(p) {
      var archive;
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return existsSync(p);
      }
      archive = getOrCreateArchive(asarPath);
      if (!archive) {
        return false;
      }
      return archive.stat(filePath) !== false;
    };
    readFile = fs.readFile;
    fs.readFile = function(p, options, callback) {
      var archive, buffer, encoding, fd, info, realPath;
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return readFile.apply(this, arguments);
      }
      if (typeof options === 'function') {
        callback = options;
        options = void 0;
      }
      archive = getOrCreateArchive(asarPath);
      if (!archive) {
        return invalidArchiveError(asarPath, callback);
      }
      info = archive.getFileInfo(filePath);
      if (!info) {
        return notFoundError(asarPath, filePath, callback);
      }
      if (info.size === 0) {
        return process.nextTick(function() {
          return callback(null, new Buffer(0));
        });
      }
      if (info.unpacked) {
        realPath = archive.copyFileOut(filePath);
        return fs.readFile(realPath, options, callback);
      }
      if (!options) {
        options = {
          encoding: null
        };
      } else if (util.isString(options)) {
        options = {
          encoding: options
        };
      } else if (!util.isObject(options)) {
        throw new TypeError('Bad arguments');
      }
      encoding = options.encoding;
      buffer = new Buffer(info.size);
      fd = archive.getFd();
      if (!(fd >= 0)) {
        return notFoundError(asarPath, filePath, callback);
      }
      logASARAccess(asarPath, filePath, info.offset);
      return fs.read(fd, buffer, 0, info.size, info.offset, function(error) {
        return callback(error, encoding ? buffer.toString(encoding) : buffer);
      });
    };
    readFileSync = fs.readFileSync;
    fs.readFileSync = function(p, opts) {
      // this allows v8 to optimize this function
      var archive, buffer, encoding, fd, info, options, realPath;
      options = opts;
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return readFileSync.apply(this, arguments);
      }
      archive = getOrCreateArchive(asarPath);
      if (!archive) {
        invalidArchiveError(asarPath);
      }
      info = archive.getFileInfo(filePath);
      if (!info) {
        notFoundError(asarPath, filePath);
      }
      if (info.size === 0) {
        if (options) {
          return '';
        } else {
          return new Buffer(0);
        }
      }
      if (info.unpacked) {
        realPath = archive.copyFileOut(filePath);
        return fs.readFileSync(realPath, options);
      }
      if (!options) {
        options = {
          encoding: null
        };
      } else if (util.isString(options)) {
        options = {
          encoding: options
        };
      } else if (!util.isObject(options)) {
        throw new TypeError('Bad arguments');
      }
      encoding = options.encoding;
      buffer = new Buffer(info.size);
      fd = archive.getFd();
      if (!(fd >= 0)) {
        notFoundError(asarPath, filePath);
      }
      logASARAccess(asarPath, filePath, info.offset);
      fs.readSync(fd, buffer, 0, info.size, info.offset);
      if (encoding) {
        return buffer.toString(encoding);
      } else {
        return buffer;
      }
    };
    readdir = fs.readdir;
    fs.readdir = function(p, callback) {
      var archive, files;
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return readdir.apply(this, arguments);
      }
      archive = getOrCreateArchive(asarPath);
      if (!archive) {
        return invalidArchiveError(asarPath, callback);
      }
      files = archive.readdir(filePath);
      if (!files) {
        return notFoundError(asarPath, filePath, callback);
      }
      return process.nextTick(function() {
        return callback(null, files);
      });
    };
    readdirSync = fs.readdirSync;
    fs.readdirSync = function(p) {
      var archive, files;
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return readdirSync.apply(this, arguments);
      }
      archive = getOrCreateArchive(asarPath);
      if (!archive) {
        invalidArchiveError(asarPath);
      }
      files = archive.readdir(filePath);
      if (!files) {
        notFoundError(asarPath, filePath);
      }
      return files;
    };
    internalModuleReadFile = process.binding('fs').internalModuleReadFile;
    process.binding('fs').internalModuleReadFile = function(p) {
      var archive, buffer, fd, info, realPath;
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return internalModuleReadFile(p);
      }
      archive = getOrCreateArchive(asarPath);
      if (!archive) {
        return void 0;
      }
      info = archive.getFileInfo(filePath);
      if (!info) {
        return void 0;
      }
      if (info.size === 0) {
        return '';
      }
      if (info.unpacked) {
        realPath = archive.copyFileOut(filePath);
        return fs.readFileSync(realPath, {
          encoding: 'utf8'
        });
      }
      buffer = new Buffer(info.size);
      fd = archive.getFd();
      if (!(fd >= 0)) {
        return void 0;
      }
      logASARAccess(asarPath, filePath, info.offset);
      fs.readSync(fd, buffer, 0, info.size, info.offset);
      return buffer.toString('utf8');
    };
    internalModuleStat = process.binding('fs').internalModuleStat;
    process.binding('fs').internalModuleStat = function(p) {
      var archive, stats;
      const [isAsar, asarPath, filePath] = splitPath(p);
      if (!isAsar) {
        return internalModuleStat(p);
      }
      archive = getOrCreateArchive(asarPath);

      // -ENOENT
      if (!archive) {
        return -34;
      }
      stats = archive.stat(filePath);

      // -ENOENT
      if (!stats) {
        return -34;
      }
      if (stats.isDirectory) {
        return 1;
      } else {
        return 0;
      }
    };

    // 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') {
      mkdir = fs.mkdir;
      fs.mkdir = function(p, mode, callback) {
        if (typeof mode === 'function') {
          callback = mode;
        }
        const [isAsar, , filePath] = splitPath(p);
        if (isAsar && filePath.length) {
          return notDirError(callback);
        }
        return mkdir(p, mode, callback);
      };
      mkdirSync = fs.mkdirSync;
      fs.mkdirSync = function(p, mode) {
        const [isAsar, , filePath] = splitPath(p);
        if (isAsar && filePath.length) {
          notDirError();
        }
        return mkdirSync(p, mode);
      };
    }
    overrideAPI(fs, 'open');
    overrideAPI(child_process, 'execFile');
    overrideAPISync(process, 'dlopen', 1);
    overrideAPISync(require('module')._extensions, '.node', 1);
    overrideAPISync(fs, 'openSync');
    return overrideAPISync(child_process, 'execFileSync');
  };
})();