chore(createReadStream): rewrite in ES5 (#25)

lib/api/createReadStream.js

+var Readable = require('stream').Readable;
+
+var BigInt = require('../tools/bigint');
+var request = require('../tools/smb2-forge').request;
+
+// Where does it come from?!
+var maxPacketSize = 0x00010000;
+
+module.exports = function createReadStream(path, options, cb) {
+  if (typeof options === 'function') {
+    cb = options;
+    options = {};
+  } else if (options == null) {
+    options = {}
+  }
+
+  var connection = this;
+
+  request('open', { path: path }, connection, function(err, file) {
+    if (err != null) {
+      return cb(err);
+    }
+
+    var offset = new BigInt(file.EndofFile.length, options.start || 0);
+    var fileSize = BigInt.fromBuffer(file.EndofFile);
+
+    var end = options.end
+    if (end != null) {
+      end = new BigInt(8, end + 1)
+      if (end.gt(fileSize)) {
+        fileSize = end
+      }
+    }
+
+    var close = request.bind(undefined, 'close', file, connection);
+
+    var stream = new Readable();
+    stream._destroy = function(err, cb) {
+      close(function(err2) {
+        if (err != null) {
+          return cb(err2);
+        }
+        cb(err);
+      });
+    };
+    var running = false;
+    stream._read = function(size) {
+      if (running) {
+        return;
+      }
+
+      if (offset.ge(fileSize)) {
+        return close(function () {
+          this.push(null)
+        })
+      }
+
+      running = true;
+      request(
+        'read',
+        {
+          FileId: file.FileId,
+          Length: Math.min(maxPacketSize, size),
+          Offset: offset.toBuffer(),
+        },
+        connection,
+        function(err, content) {
+          try {
+            if (err != null) {
+              return process.nextTick(stream.emit.bind(stream, 'error', err));
+            }
+
+            offset = offset.add(content.length);
+            stream.push(content);
+          } finally {
+            running = false;
+          }
+        }
+      );
+    };
+    cb(null, stream);
+  });
+};

lib/api/src/createReadStream.js

-import Bigint from '../tools/bigint';
-import Bluebird from 'bluebird';
-import { Readable } from 'stream';
-import { request } from '../tools/smb2-forge';
-
-const requestAsync = Bluebird.promisify(request);
-
-const maxPacketSize = 0x00010000;
-
-class SmbReadableStream extends Readable {
-  constructor(connection, file, options = {}) {
-    super(options);
-
-    const { start = 0, end, encoding } = options;
-
-    this.connection = connection;
-    this.encoding = encoding;
-    this.file = file;
-    this.offset = new Bigint(8, start);
-
-    let fileLength = 0;
-    for (let i = 0; i < file.EndofFile.length; i++) {
-      fileLength += file.EndofFile[i] * Math.pow(2, i * 8);
-    }
-    this.fileLength = fileLength;
-    this.wait = false;
-
-    if (end >= 0 && end < fileLength) {
-      this.fileLength = end + 1;
-    }
-  }
-
-  async _read(size) {
-    while (this.offset.lt(this.fileLength) /* && size > 0*/) {
-      if (this.wait) {
-        return;
-      }
-      const rest = this.offset.sub(this.fileLength).neg();
-      const packetSize = Math.min(maxPacketSize, rest.toNumber() /*, size*/);
-
-      const offset = new Bigint(this.offset);
-      this.wait = true;
-      let content = await requestAsync(
-        'read',
-        {
-          FileId: this.file.FileId,
-          Length: packetSize,
-          Offset: offset.toBuffer(),
-        },
-        this.connection
-      );
-      this.wait = false;
-
-      if (this.encoding) {
-        content = content.toString(this.encoding);
-      }
-      this.offset = this.offset.add(packetSize);
-      // size -= packetSize
-      if (!this.push(content)) {
-        return;
-      }
-    }
-    if (this.offset.ge(this.fileLength)) {
-      this.push(null);
-      await requestAsync('close', this.file, this.connection);
-    }
-  }
-}
-
-export default function(path, options, cb) {
-  if (typeof options === 'function') {
-    cb = options;
-    options = {};
-  }
-  request('open', { path }, this, (err, file) => {
-    if (err) {
-      if (err.code === 'STATUS_OBJECT_NAME_NOT_FOUND') {
-        err.code = 'ENOENT';
-      }
-      cb(err);
-    } else {
-      cb(null, new SmbReadableStream(this, file, options));
-    }
-  });
-}