Completed buffered recv implementation.

asio/include/asio/buffered_recv_stream.hpp

@@ -23,6 +23,9 @@
 #include <boost/type_traits.hpp>
 #include "asio/detail/pop_options.hpp"
 
+#include "asio/null_completion_context.hpp"
+#include "asio/detail/bind_handler.hpp"
+
 namespace asio {
 
 /// The buffered_recv_stream class template can be used to add buffering to the
@@ -102,8 +105,6 @@ public:
   /// 0 if the stream was closed cleanly. Throws an exception on failure.
   size_t recv(void* data, size_t max_length)
   {
-    using namespace std; // For memcpy.
-
     if (read_pos_ == bytes_in_buffer_)
     {
       bytes_in_buffer_ = next_layer_.recv(buffer_, Buffer_Size);
@@ -112,19 +113,80 @@ public:
         return 0;
     }
 
-    size_t bytes_avail = bytes_in_buffer_ - read_pos_;
-    size_t length = (max_length < bytes_avail) ? max_length : bytes_avail;
-    memcpy(data, buffer_ + read_pos_, length);
-    read_pos_ += length;
-    return length;
+    return copy(data, max_length);
   }
 
+  template <typename Handler, typename Completion_Context>
+  class recv_handler
+  {
+  public:
+    recv_handler(demuxer_type& demuxer, char* buffer,
+        size_t& bytes_in_buffer, size_t& read_pos, void* data,
+        size_t max_length, Handler handler, Completion_Context& context)
+      : demuxer_(demuxer),
+        buffer_(buffer),
+        bytes_in_buffer_(bytes_in_buffer),
+        read_pos_(read_pos),
+        data_(data),
+        max_length_(max_length),
+        handler_(handler),
+        context_(context)
+    {
+    }
+
+    template <typename Error>
+    void operator()(const Error& e, size_t bytes_recvd)
+    {
+      bytes_in_buffer_ = bytes_recvd;
+      read_pos_ = 0;
+      if (bytes_in_buffer_ == 0)
+      {
+        demuxer_.operation_immediate(detail::bind_handler(handler_, e, 0),
+            context_);
+      }
+      else
+      {
+        using namespace std; // For memcpy.
+
+        size_t bytes_avail = bytes_in_buffer_ - read_pos_;
+        size_t length = (max_length_ < bytes_avail)
+          ? max_length_ : bytes_avail;
+        memcpy(data_, buffer_ + read_pos_, length);
+        read_pos_ += length;
+        demuxer_.operation_immediate(
+            detail::bind_handler(handler_, e, length), context_);
+      }
+    }
+
+  private:
+    demuxer_type& demuxer_;
+    char* buffer_;
+    size_t& bytes_in_buffer_;
+    size_t& read_pos_;
+    void* data_;
+    size_t max_length_;
+    Handler handler_;
+    Completion_Context& context_;
+  };
+
   /// Start an asynchronous receive. The buffer for the data being received
   /// must be valid for the lifetime of the asynchronous operation.
   template <typename Handler>
   void async_recv(void* data, size_t max_length, Handler handler)
   {
-    next_layer_.async_recv(data, max_length, handler);
+    if (read_pos_ == bytes_in_buffer_)
+    {
+      next_layer_.async_recv(buffer_, Buffer_Size,
+          recv_handler<Handler, null_completion_context>(demuxer(), buffer_,
+            bytes_in_buffer_, read_pos_, data, max_length, handler,
+            null_completion_context::instance()));
+    }
+    else
+    {
+      size_t length = copy(data, max_length);
+      next_layer_.demuxer().operation_immediate(
+          detail::bind_handler(handler, 0, length));
+    }
   }
 
   /// Start an asynchronous receive. The buffer for the data being received
@@ -133,10 +195,35 @@ public:
   void async_recv(void* data, size_t max_length, Handler handler,
       Completion_Context& context)
   {
-    next_layer_.async_recv(data, max_length, handler, context);
+    if (read_pos_ == bytes_in_buffer_)
+    {
+      next_layer_.async_recv(buffer_, Buffer_Size,
+          recv_handler<Handler, Completion_Context>(demuxer(), buffer_,
+            bytes_in_buffer_, read_pos_, data, max_length, handler, context));
+    }
+    else
+    {
+      size_t length = copy(data, max_length);
+      next_layer_.demuxer().operation_immediate(
+          detail::bind_handler(handler, 0, length), context);
+    }
   }
 
 private:
+  /// Copy data out of the internal buffer to the specified target buffer.
+  /// Returns the number of bytes copied.
+  size_t copy(void* data, size_t max_length)
+  {
+    using namespace std; // For memcpy.
+
+    size_t bytes_avail = bytes_in_buffer_ - read_pos_;
+    size_t length = (max_length < bytes_avail) ? max_length : bytes_avail;
+    memcpy(data, buffer_ + read_pos_, length);
+    read_pos_ += length;
+
+    return length;
+  }
+
   /// The next layer.
   Next_Layer next_layer_;