Implement end-of-file condition for WinRT stream sockets.

Author: chriskohlhoff

asio/include/asio/detail/impl/winrt_ssocket_service_base.ipp

@@ -542,7 +542,13 @@ std::size_t winrt_ssocket_service_base::do_receive(
           bufs.buffers()[0], bufs.buffers()[0]->Capacity,
           Windows::Storage::Streams::InputStreamOptions::Partial), ec);
 
-    return bufs.buffers()[0]->Length;
+    std::size_t bytes_transferred = bufs.buffers()[0]->Length;
+    if (bytes_transferred == 0 && !ec)
+    {
+      ec = asio::error::eof;
+    }
+
+    return bytes_transferred;
   }
   catch (Platform::Exception^ e)
   {

asio/include/asio/detail/winrt_socket_recv_op.hpp

@@ -66,7 +66,13 @@ class winrt_socket_recv_op :
     }
 #endif // defined(ASIO_ENABLE_BUFFER_DEBUGGING)
 
-    // TODO check for end-of-file.
+    std::size_t bytes_transferred = o->result_ ? o->result_->Length : 0;
+    if (bytes_transferred == 0 && !o->ec_ &&
+        !buffer_sequence_adapter<asio::mutable_buffer,
+          MutableBufferSequence>::all_empty(o->buffers_))
+    {
+      o->ec_ = asio::error::eof;
+    }
 
     // Make a copy of the handler so that the memory can be deallocated before
     // the upcall is made. Even if we're not about to make an upcall, a
@@ -75,7 +81,7 @@ class winrt_socket_recv_op :
     // to ensure that any owning sub-object remains valid until after we have
     // deallocated the memory here.
     detail::binder2<Handler, asio::error_code, std::size_t>
-      handler(o->handler_, o->ec_, o->result_ ? o->result_->Length : 0);
+      handler(o->handler_, o->ec_, bytes_transferred);
     p.h = asio::detail::addressof(handler.handler_);
     p.reset();