face: UnixStream{Face,Channel,ChannelFactory} implementation.

refs: #1174

Change-Id: I14d1e357c96a02995355e7970323fe40847580aa
diff --git a/daemon/face/unix-stream-channel.cpp b/daemon/face/unix-stream-channel.cpp
new file mode 100644
index 0000000..428d33e
--- /dev/null
+++ b/daemon/face/unix-stream-channel.cpp
@@ -0,0 +1,101 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (C) 2014 Named Data Networking Project
+ * See COPYING for copyright and distribution information.
+ */
+
+#include "unix-stream-channel.hpp"
+
+#include <boost/filesystem.hpp>
+
+namespace nfd {
+
+NFD_LOG_INIT("UnixStreamChannel");
+
+using namespace boost::asio::local;
+
+UnixStreamChannel::UnixStreamChannel(boost::asio::io_service& ioService,
+                                     const unix_stream::Endpoint& endpoint)
+  : m_ioService(ioService)
+  , m_endpoint(endpoint)
+{
+}
+
+UnixStreamChannel::~UnixStreamChannel()
+{
+  if (m_acceptor)
+    {
+      // use the non-throwing variants during destruction
+      // and ignore any errors
+      boost::system::error_code error;
+      m_acceptor->close(error);
+      boost::filesystem::remove(m_endpoint.path(), error);
+    }
+}
+
+void
+UnixStreamChannel::listen(const FaceCreatedCallback& onFaceCreated,
+                          const ConnectFailedCallback& onAcceptFailed,
+                          int backlog/* = acceptor::max_connections*/)
+{
+  if (m_acceptor) // already listening
+    return;
+
+  namespace fs = boost::filesystem;
+  fs::path p(m_endpoint.path());
+  if (fs::symlink_status(p).type() == fs::socket_file)
+    {
+      // for safety, remove an already existing file only if it's a socket
+      fs::remove(p);
+    }
+
+  m_acceptor = make_shared<stream_protocol::acceptor>(boost::ref(m_ioService));
+  m_acceptor->open(m_endpoint.protocol());
+  m_acceptor->bind(m_endpoint);
+  m_acceptor->listen(backlog);
+
+  shared_ptr<stream_protocol::socket> clientSocket =
+    make_shared<stream_protocol::socket>(boost::ref(m_ioService));
+  m_acceptor->async_accept(*clientSocket,
+                           bind(&UnixStreamChannel::handleSuccessfulAccept, this, _1,
+                                clientSocket, onFaceCreated, onAcceptFailed));
+}
+
+void
+UnixStreamChannel::createFace(const shared_ptr<stream_protocol::socket>& socket,
+                              const FaceCreatedCallback& onFaceCreated)
+{
+  shared_ptr<UnixStreamFace> face = make_shared<UnixStreamFace>(boost::cref(socket));
+  onFaceCreated(face);
+}
+
+void
+UnixStreamChannel::handleSuccessfulAccept(const boost::system::error_code& error,
+                                          const shared_ptr<stream_protocol::socket>& socket,
+                                          const FaceCreatedCallback& onFaceCreated,
+                                          const ConnectFailedCallback& onAcceptFailed)
+{
+  if (error) {
+    if (error == boost::system::errc::operation_canceled) // when socket is closed by someone
+      return;
+
+    NFD_LOG_DEBUG("Connection failed: "
+                  << error.category().message(error.value()));
+
+    onAcceptFailed("Connection failed: " +
+                   error.category().message(error.value()));
+    return;
+  }
+
+  // prepare accepting the next connection
+  shared_ptr<stream_protocol::socket> clientSocket =
+    make_shared<stream_protocol::socket>(boost::ref(m_ioService));
+  m_acceptor->async_accept(*clientSocket,
+                           bind(&UnixStreamChannel::handleSuccessfulAccept, this, _1,
+                                clientSocket, onFaceCreated, onAcceptFailed));
+
+  NFD_LOG_DEBUG("[" << m_endpoint << "] << Incoming connection");
+  createFace(socket, onFaceCreated);
+}
+
+} // namespace nfd