(websocket) use persistent member variable as temp variables to encode/decode zlib messages in order to reduce transient allocations

docs/CHANGELOG.md

@@ -1,6 +1,10 @@
 # Changelog
 All changes to this project will be documented in this file.
 
+## [9.2.4] - 2020-04-13
+
+(websocket) use persistent member variable as temp variables to encode/decode zlib messages in order to reduce transient allocations
+
 ## [9.2.3] - 2020-04-13
 
 (ws) add a --runtime option to ws cobra_subscribe to optionally limit how much time it will run

ixwebsocket/IXWebSocketMessage.h

@@ -19,7 +19,7 @@ namespace ix
     struct WebSocketMessage
     {
         WebSocketMessageType type;
-        std::string str;
+        const std::string& str;
         size_t wireSize;
         WebSocketErrorInfo errorInfo;
         WebSocketOpenInfo openInfo;
@@ -34,7 +34,7 @@ namespace ix
                          WebSocketCloseInfo c,
                          bool b = false)
             : type(t)
-            , str(std::move(s))
+            , str(s)
             , wireSize(w)
             , errorInfo(e)
             , openInfo(o)

ixwebsocket/IXWebSocketPerMessageDeflateCodec.cpp

@@ -87,6 +87,9 @@ namespace ix
         //
         size_t output;
 
+        // Clear output
+        out.clear();
+
         if (in.empty())
         {
             // See issue #167
@@ -174,6 +177,9 @@ namespace ix
         _inflateState.avail_in = (uInt) inFixed.size();
         _inflateState.next_in = (unsigned char*) (const_cast<char*>(inFixed.data()));
 
+        // Clear output
+        out.clear();
+
         do
         {
             _inflateState.avail_out = (uInt) _compressBufferSize;

ixwebsocket/IXWebSocketTransport.cpp

@@ -62,7 +62,7 @@ namespace ix
     WebSocketTransport::WebSocketTransport()
         : _useMask(true)
         , _blockingSend(false)
-        , _compressedMessage(false)
+        , _receivedMessageCompressed(false)
         , _readyState(ReadyState::CLOSED)
         , _closeCode(WebSocketCloseConstants::kInternalErrorCode)
         , _closeReason(WebSocketCloseConstants::kInternalErrorMessage)
@@ -493,7 +493,7 @@ namespace ix
                                                  ? MessageKind::MSG_TEXT
                                                  : MessageKind::MSG_BINARY;
 
-                    _compressedMessage = _enablePerMessageDeflate && ws.rsv1;
+                    _receivedMessageCompressed = _enablePerMessageDeflate && ws.rsv1;
 
                     // Continuation message needs to follow a non-fin TEXT or BINARY message
                     if (!_chunks.empty())
@@ -516,9 +516,9 @@ namespace ix
                 if (ws.fin && _chunks.empty())
                 {
                     emitMessage(
-                        _fragmentedMessageKind, frameData, _compressedMessage, onMessageCallback);
+                        _fragmentedMessageKind, frameData, _receivedMessageCompressed, onMessageCallback);
 
-                    _compressedMessage = false;
+                    _receivedMessageCompressed = false;
                 }
                 else
                 {
@@ -535,11 +535,11 @@ namespace ix
                     {
                         emitMessage(_fragmentedMessageKind,
                                     getMergedChunks(),
-                                    _compressedMessage,
+                                    _receivedMessageCompressed,
                                     onMessageCallback);
 
                         _chunks.clear();
-                        _compressedMessage = false;
+                        _receivedMessageCompressed = false;
                     }
                     else
                     {
@@ -712,17 +712,16 @@ namespace ix
         // When the RSV1 bit is 1 it means the message is compressed
         if (compressedMessage && messageKind != MessageKind::FRAGMENT)
         {
-            std::string decompressedMessage;
+            bool success = _perMessageDeflate->decompress(message, _decompressedMessage);
-            bool success = _perMessageDeflate->decompress(message, decompressedMessage);
 
-            if (messageKind == MessageKind::MSG_TEXT && !validateUtf8(decompressedMessage))
+            if (messageKind == MessageKind::MSG_TEXT && !validateUtf8(_decompressedMessage))
             {
                 close(WebSocketCloseConstants::kInvalidFramePayloadData,
                       WebSocketCloseConstants::kInvalidFramePayloadDataMessage);
             }
             else
             {
-                onMessageCallback(decompressedMessage, wireSize, !success, messageKind);
+                onMessageCallback(_decompressedMessage, wireSize, !success, messageKind);
             }
         }
         else
@@ -759,7 +758,6 @@ namespace ix
 
         size_t payloadSize = message.size();
         size_t wireSize = message.size();
-        std::string compressedMessage;
         bool compressionError = false;
 
         std::string::const_iterator message_begin = message.begin();
@@ -767,7 +765,7 @@ namespace ix
 
         if (compress)
         {
-            if (!_perMessageDeflate->compress(message, compressedMessage))
+            if (!_perMessageDeflate->compress(message, _compressedMessage))
             {
                 bool success = false;
                 compressionError = true;
@@ -776,10 +774,10 @@ namespace ix
                 return WebSocketSendInfo(success, compressionError, payloadSize, wireSize);
             }
             compressionError = false;
-            wireSize = compressedMessage.size();
+            wireSize = _compressedMessage.size();
 
-            message_begin = compressedMessage.begin();
+            message_begin = _compressedMessage.begin();
-            message_end = compressedMessage.end();
+            message_end = _compressedMessage.end();
         }
 
         {

ixwebsocket/IXWebSocketTransport.h

@@ -165,7 +165,7 @@ namespace ix
         MessageKind _fragmentedMessageKind;
 
         // Ditto for whether a message is compressed
-        bool _compressedMessage;
+        bool _receivedMessageCompressed;
 
         // Fragments are 32K long
         static constexpr size_t kChunkSize = 1 << 15;
@@ -189,6 +189,9 @@ namespace ix
         WebSocketPerMessageDeflateOptions _perMessageDeflateOptions;
         std::atomic<bool> _enablePerMessageDeflate;
 
+        std::string _decompressedMessage;
+        std::string _compressedMessage;
+
         // Used to control TLS connection behavior
         SocketTLSOptions _socketTLSOptions;
 

ixwebsocket/IXWebSocketVersion.h

@@ -6,4 +6,4 @@
 
 #pragma once
 
-#define IX_WEBSOCKET_VERSION "9.2.3"
+#define IX_WEBSOCKET_VERSION "9.2.4"