Improved memory allocations in TcpConnection class

Reduced allocations/reallocations, better handling and recovery from oversized messages. Updated doxygen docs.

Author: dac1976

.vscode/launch.json

@@ -21,7 +21,7 @@
       "request": "launch",
       "program": "${input:unitTestProgramWin}",
       "args": [
-        "--gtest_filter=AsioTest.testCase_testNetUtils_GetIpAndSubnetMasks",
+        "--gtest_filter=AsioTest.testCase_TestSimpleSync_Large",
         "--gtest_break_on_failure",
         "--gtest_catch_exceptions=0"
       ],

Include/Asio/AsioDefines.h

@@ -166,7 +166,8 @@ namespace tcp
 /*! \brief Default internal receive buffer's initial reserved size in bytes. */
 enum eDefReservedSize : size_t
 {
-    DEFAULT_RESERVED_SIZE = 512 * 1024
+    DEFAULT_SMALL_RESERVED_SIZE = 65536,
+    DEFAULT_LARGE_RESERVED_SIZE = 1048576
 };
 
 /*! \brief Maximum number of unsent async messages allowed on TCP socket IO Service queue */

Include/Asio/MessageUtils.h

@@ -116,7 +116,7 @@ class CORE_LIBRARY_DLL_SHARED_API MessageHandler final
      * \brief Get next message to use from pool.
      * \return A new message object or a one from the pool.
      */
-    defs::default_received_message_ptr_t GetNewMessgeObject() const;
+    defs::default_received_message_ptr_t GetNewMessageObject() const;
 
 private:
     mutable std::mutex m_mutex;

Include/Asio/TcpConnection.h

@@ -34,6 +34,7 @@
 #include <deque>
 #include <utility>
 #include <atomic>
+#include <array>
 
 /*! \brief The core_lib namespace. */
 namespace core_lib
@@ -282,7 +283,7 @@ class CORE_LIBRARY_DLL_SHARED_API TcpConnection final
     /*! \brief Structure holding socket connection options and behavioural settings. */
     TcpConnSettings m_settings;
     /*! \brief Socket receive buffer. */
-    defs::char_buffer_t m_receiveBuffer;
+    std::array<char, DEFAULT_SMALL_RESERVED_SIZE> m_receiveBuffer;
     /*! \brief Message buffer. */
     defs::char_buffer_t m_messageBuffer;
     /*! \brief Unsent async message reservation counter (thread-safe). */

Source/Asio/MessageUtils.cpp

@@ -135,7 +135,7 @@ void MessageHandler::MessageReceivedHandler(defs::char_buf_cspan_t message) cons
 #endif
     }
 
-    auto receivedMessage = GetNewMessgeObject();
+    auto receivedMessage = GetNewMessageObject();
 
     if (!TryConvertToPod<defs::MessageHeader>(receivedMessage->header, message))
     {
@@ -199,7 +199,7 @@ void MessageHandler::InitialiseMsgPool(size_t memPoolMsgCount, size_t defaultMsg
     std::generate(m_msgPool.begin(), m_msgPool.end(), generateMsg);
 }
 
-defs::default_received_message_ptr_t MessageHandler::GetNewMessgeObject() const
+defs::default_received_message_ptr_t MessageHandler::GetNewMessageObject() const
 {
     defs::default_received_message_ptr_t newMessage;
 

Source/Asio/TcpConnection.cpp

@@ -70,8 +70,7 @@ TcpConnection::TcpConnection(asio_compat::io_service_t&                    ioSer
         "Reserving memory for receive and send buffers as: " << DEFAULT_RESERVED_SIZE << " bytes");
 #endif
 
-    m_receiveBuffer.reserve(DEFAULT_RESERVED_SIZE);
-    m_messageBuffer.reserve(DEFAULT_RESERVED_SIZE);
+    m_messageBuffer.reserve(DEFAULT_LARGE_RESERVED_SIZE);
 }
 
 boost_tcp_t::socket& TcpConnection::Socket()
@@ -301,11 +300,9 @@ void TcpConnection::StartAsyncRead(const defs::connection_t& endPoint)
 
 void TcpConnection::AsyncReadFromSocket(size_t amountToRead)
 {
-    m_receiveBuffer.resize(amountToRead);
-
     // Wrap in strand just to be safe in case of multiple threads running the IO service.
     boost_asio::async_read(m_socket,
-                           boost_asio::buffer(m_receiveBuffer),
+                           boost_asio::buffer(m_receiveBuffer.data(), amountToRead),
                            asio_compat::wrap(m_strand,
                                              boost::bind(&TcpConnection::ReadComplete,
                                                          shared_from_this(),
@@ -351,6 +348,7 @@ void TcpConnection::ReadComplete(const boost_sys::error_code& error, size_t byte
             // back_inserter solution.
             auto const currentSize = m_messageBuffer.size();
             m_messageBuffer.resize(currentSize + bytesReceived);
+
             auto dataWritePos = m_messageBuffer.data() + currentSize;
             std::copy(m_receiveBuffer.data(), m_receiveBuffer.data() + bytesReceived, dataWritePos);
 
@@ -394,8 +392,16 @@ void TcpConnection::ReadComplete(const boost_sys::error_code& error, size_t byte
             else if (std::numeric_limits<size_t>::max() == numBytes)
             {
                 // We have a problem.
+                numBytes    = m_settings.minAmountToRead;
                 clearMsgBuf = true;
             }
+            else
+            {
+                // We do not want to ever reallocate the m_receiveBuffer beyond its initial
+                // size, as this would cause a significant performance hit. We will always
+                // read in up to DEFAULT_SMALL_RESERVED_SIZE chunks.
+                numBytes = std::min(numBytes, static_cast<size_t>(DEFAULT_SMALL_RESERVED_SIZE));
+            }
         }
         catch (...)
         {
@@ -411,7 +417,16 @@ void TcpConnection::ReadComplete(const boost_sys::error_code& error, size_t byte
 
     if (clearMsgBuf)
     {
-        m_messageBuffer.clear();
+        if (m_messageBuffer.capacity() > DEFAULT_LARGE_RESERVED_SIZE)
+        {
+            defs::char_buffer_t tmp;
+            tmp.reserve(DEFAULT_LARGE_RESERVED_SIZE);
+            m_messageBuffer.swap(tmp);
+        }
+        else
+        {
+            m_messageBuffer.clear();
+        }
     }
 
     if (numBytes > 0)

docs/Doxyfile

@@ -48,7 +48,7 @@ PROJECT_NAME           = "Core Library"
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 2.0.3
+PROJECT_NUMBER         = 2.0.4
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewers a

docs/html/_abstract_factory_8h_source.html

@@ -26,7 +26,7 @@
  <tbody>
  <tr id="projectrow">
   <td id="projectalign">
-   <div id="projectname">Core Library<span id="projectnumber">&#160;2.0.3</span>
+   <div id="projectname">Core Library<span id="projectnumber">&#160;2.0.4</span>
    </div>
    <div id="projectbrief">Library containing core utilities and tools for threading, networking, logging, INI and CSV file management etc.</div>
   </td>

docs/html/_allocator_8h_source.html

@@ -26,7 +26,7 @@
  <tbody>
  <tr id="projectrow">
   <td id="projectalign">
-   <div id="projectname">Core Library<span id="projectnumber">&#160;2.0.3</span>
+   <div id="projectname">Core Library<span id="projectnumber">&#160;2.0.4</span>
    </div>
    <div id="projectbrief">Library containing core utilities and tools for threading, networking, logging, INI and CSV file management etc.</div>
   </td>

docs/html/_asio_compatibility_8hpp.html

@@ -26,7 +26,7 @@
  <tbody>
  <tr id="projectrow">
   <td id="projectalign">
-   <div id="projectname">Core Library<span id="projectnumber">&#160;2.0.3</span>
+   <div id="projectname">Core Library<span id="projectnumber">&#160;2.0.4</span>
    </div>
    <div id="projectbrief">Library containing core utilities and tools for threading, networking, logging, INI and CSV file management etc.</div>
   </td>