Added synchronous socket implementation to dart:io.

sdk/lib/io/sync_socket.dart

Index: sdk/lib/io/sync_socket.dart
diff --git a/sdk/lib/io/sync_socket.dart b/sdk/lib/io/sync_socket.dart
new file mode 100644
index 0000000000000000000000000000000000000000..cc055a7f9d6be171d01663dca61646e2d80f83a1
--- /dev/null
+++ b/sdk/lib/io/sync_socket.dart
@@ -0,0 +1,108 @@
+// Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+part of dart.io;
+
+/**
+ * A low-level class for communicating synchronously over a TCP socket.
+ *
+ * Warning: [RawSynchronousSocket] should probably only be used to connect to
+ * 'localhost'. The operations below will block the calling thread to wait for
+ * a response from the network. The thread can process no other events while
+ * waiting for these operations to complete. [RawSynchronousSocket] is not
+ * suitable for applications that require high performance or asynchronous I/O
+ * such as a server. Instead such applications should use the non-blocking
+ * sockets and asynchronous operations in the Socket or RawSocket classes.
+ */
+abstract class RawSynchronousSocket {
+  /**
+   * Creates a new socket connection and returns a [RawSynchronousSocket].
+   *
+   * [host] can either be a [String] or an [InternetAddress]. If [host] is a
+   * [String], [connectSync] will perform a [InternetAddress.lookup] and try
+   * all returned [InternetAddress]es, until connected. Unless a
+   * connection was established, the error from the first failing connection is
+   * returned.
+   */
+  external static RawSynchronousSocket connectSync(host, int port);
+
+  /**
+   * Returns the number of received and unread bytes in the socket that can be
+   * read.
+   */
+  int available();
+
+  /**
+   * Closes the [RawSynchronousSocket].
+   *
+   * Once [closeSync] has been called, attempting to call [readSync],
+   * [readIntoSync], [writeFromSync], [remoteAddress], and [remotePort] will
+   * cause a [SocketException] to be thrown.
+   */
+  void closeSync();
+
+  /**
+   * Reads into an existing [List<int>] from the socket into the range:
+   * [[start],[end]).
+   *
+   * Reads into an existing [List<int>] from the socket. If [start] is present,
+   * the bytes will be filled into [buffer] from index [start], otherwise index
+   * 0. If [end] is present, [end] - [start] bytes will be read into [buffer],
+   * otherwise up to [buffer.length]. If [end] == [start], no bytes are read.
+   * Returns the number of bytes read.
+   */
+  int readIntoSync(List<int> buffer, [int start = 0, int end]);
+
+  /**
+   * Reads up to [bytes] bytes from the socket.
+   *
+   * Blocks and waits for a response of up to a specified number of bytes
+   * sent by the socket. [bytes] specifies the maximum number of bytes to
+   * be read. Returns the list of bytes read, which could be less than the
+   * value specified by [bytes].
+   */
+  List<int> readSync(int bytes);
+
+  /**
+   * Shutdown a socket in the provided direction.
+   *
+   * Calling shutdown will never throw an exception and calling it several times
+   * is supported. If both [RECEIVE] and [SEND] directions are closed, the
+   * socket is closed completely, the same as if [closeSync] has been called.
+   */
+  void shutdown(SocketDirection direction);
+
+  /**
+   * Writes data from a specified range in a [List<int>] to the socket.
+   *
+   * Writes into the socket from a [List<int>]. If [start] is present, the bytes
+   * will be written to the socket starting from index [start]. If [start] is
+   * not present, the bytes will be written starting from index 0. If [end] is
+   * present, the [end] - [start] bytes will be written into the socket starting
+   * at index [start]. If [end] is not provided, [buffer.length] elements will
+   * be written to the socket starting from index [start]. If [end] == [start],
+   * nothing happens.
+   */
+  void writeFromSync(List<int> buffer, [int start = 0, int end]);
+
+  /**
+   * The port used by this socket.
+   */
+  int get port;
+
+  /**
+   * The remote port connected to by this socket.
+   */
+  int get remotePort;
+
+  /**
+   * The [InternetAddress] used to connect this socket.
+   */
+  InternetAddress get address;
+
+  /**
+   * The remote [InternetAddress] connected to by this socket.
+   */
+  InternetAddress get remoteAddress;
+}