diff --git a/poseidon/base/deflator.cpp b/poseidon/base/deflator.cpp
index 025e8ee5..6b7f38ee 100644
--- a/poseidon/base/deflator.cpp
+++ b/poseidon/base/deflator.cpp
@@ -32,9 +32,9 @@ deflate(chars_view data)
     if(data.n == 0)
       return 0;
 
+    int err;
     const char* in_ptr = data.p;
     const char* in_end = in_ptr + data.n;
-    int err;
 
     do {
       // Allocate an output buffer and write compressed data there.
@@ -66,9 +66,9 @@ bool
 Deflator::
 sync_flush()
   {
+    int err;
     const char* in_ptr = "";
     const char* in_end = in_ptr;
-    int err;
 
     do {
       // Allocate an output buffer and write compressed data there.
@@ -100,9 +100,9 @@ bool
 Deflator::
 full_flush()
   {
+    int err;
     const char* in_ptr = "";
     const char* in_end = in_ptr;
-    int err;
 
     do {
       // Allocate an output buffer and write compressed data there.
@@ -134,9 +134,9 @@ bool
 Deflator::
 finish()
   {
+    int err;
     const char* in_ptr = "";
     const char* in_end = in_ptr;
-    int err;
 
     do {
       // Allocate an output buffer and write compressed data there.
diff --git a/poseidon/base/inflator.cpp b/poseidon/base/inflator.cpp
index 11b93c68..2cfbc670 100644
--- a/poseidon/base/inflator.cpp
+++ b/poseidon/base/inflator.cpp
@@ -29,9 +29,12 @@ size_t
 Inflator::
 inflate(chars_view data)
   {
+    if(data.n == 0)
+      return 0;
+
+    int err;
     const char* in_ptr = data.p;
     const char* in_end = in_ptr + data.n;
-    int err;
 
     do {
       constexpr size_t out_request = 128;
@@ -62,9 +65,9 @@ bool
 Inflator::
 finish()
   {
+    int err;
     const char* in_ptr = "";
     const char* in_end = in_ptr;
-    int err;
 
     do {
       // Allocate an output buffer and write compressed data there.
diff --git a/poseidon/http/websocket_deflator.cpp b/poseidon/http/websocket_deflator.cpp
index 533e574e..bb4e05a4 100644
--- a/poseidon/http/websocket_deflator.cpp
+++ b/poseidon/http/websocket_deflator.cpp
@@ -32,14 +32,13 @@ void
 WebSocket_Deflator::
 deflate_message_stream(plain_mutex::unique_lock& lock, chars_view data)
   {
-    lock.lock(this->m_def_mtx);
-
     if(data.n == 0)
       return;
 
+    lock.lock(this->m_def_mtx);
+    int err;
     const char* in_ptr = data.p;
     const char* in_end = in_ptr + data.n;
-    int err;
 
     do {
       // Allocate an output buffer and write compressed data there.
@@ -62,10 +61,9 @@ WebSocket_Deflator::
 deflate_message_finish(plain_mutex::unique_lock& lock)
   {
     lock.lock(this->m_def_mtx);
-
+    int err;
     const char* in_ptr = "";
     const char* in_end = in_ptr;
-    int err;
 
     do {
       // Allocate an output buffer and write compressed data there.
@@ -90,14 +88,13 @@ void
 WebSocket_Deflator::
 inflate_message_stream(plain_mutex::unique_lock& lock, chars_view data)
   {
-    lock.lock(this->m_inf_mtx);
-
     if(data.n == 0)
       return;
 
+    lock.lock(this->m_inf_mtx);
+    int err;
     const char* in_ptr = data.p;
     const char* in_end = in_ptr + data.n;
-    int err;
 
     do {
       // Allocate an output buffer and write compressed data there.
@@ -120,10 +117,9 @@ WebSocket_Deflator::
 inflate_message_finish(plain_mutex::unique_lock& lock)
   {
     lock.lock(this->m_inf_mtx);
-
+    int err;
     const char* in_ptr = "\x00\x00\xFF\xFF";
     const char* in_end = in_ptr + 4;
-    int err;
 
     do {
       // Allocate an output buffer and write compressed data there.
diff --git a/poseidon/http/websocket_frame_parser.cpp b/poseidon/http/websocket_frame_parser.cpp
index 0d5bf65e..5826f22e 100644
--- a/poseidon/http/websocket_frame_parser.cpp
+++ b/poseidon/http/websocket_frame_parser.cpp
@@ -428,14 +428,14 @@ parse_frame_header_from_stream(linear_buffer& data)
     if(this->m_wsf >= wsf_header_done)
       return;
 
-    if(this->m_msg_fin) {
+    if(this->m_fin) {
       // If a previous message has finished, forget it before a next frame. It
-      // is important for control frames to not touch `m_msg_*` fields.
-      this->m_msg_fin = 0;
-      this->m_msg_rsv1 = 0;
-      this->m_msg_rsv2 = 0;
-      this->m_msg_rsv3 = 0;
-      this->m_msg_opcode = 0;
+      // is important for control frames to not touch `m_*` fields.
+      this->m_fin = 0;
+      this->m_rsv1 = 0;
+      this->m_rsv2 = 0;
+      this->m_rsv3 = 0;
+      this->m_opcode = 0;
     }
 
     // Calculate the length of this header.
@@ -470,7 +470,7 @@ parse_frame_header_from_stream(linear_buffer& data)
       case 1:  // text data
       case 2:  // binary data
       {
-        if(this->m_msg_opcode != 0) {
+        if(this->m_opcode != 0) {
           // The previous message must have terminated.
           this->m_wsf = wsf_error;
           this->m_error_desc = "continuation frame expected";
@@ -492,14 +492,15 @@ parse_frame_header_from_stream(linear_buffer& data)
           return;
         }
 
-        // Copy message header fields for later use.
-        this->m_msg_fin = this->m_frm_header.fin;
-        this->m_msg_rsv1 = this->m_frm_header.rsv1;
-        this->m_msg_rsv2 = this->m_frm_header.rsv2;
-        this->m_msg_rsv3 = this->m_frm_header.rsv3;
-        this->m_msg_opcode = this->m_frm_header.opcode;
+        // Copy fields for later use.
+        this->m_fin = this->m_frm_header.fin;
+        this->m_rsv1 = this->m_frm_header.rsv1;
+        this->m_rsv2 = this->m_frm_header.rsv2;
+        this->m_rsv3 = this->m_frm_header.rsv3;
+        this->m_opcode = this->m_frm_header.opcode;
+        POSEIDON_LOG_TRACE(("WebSocket data frame: opcode = $1, rsv1 = $2"), this->m_opcode, this->m_rsv1);
+        break;
       }
-      break;
 
       case 0:  // continuation
       {
@@ -510,18 +511,22 @@ parse_frame_header_from_stream(linear_buffer& data)
           return;
         }
 
-        if(this->m_msg_opcode == 0) {
+        if(this->m_opcode == 0) {
           // A continuation frame must follow a data frame.
           this->m_wsf = wsf_error;
           this->m_error_desc = "dangling continuation frame";
           return;
         }
 
+        // If this is a FIN frame, terminate the current message.
         // If this is a FIN frame, terminate the current message.
         if(mask_len_rsv_opcode & 0b10000000)
-          this->m_msg_fin = 1;
+          this->m_fin = 1;
+
+        // There shall be a message payload.
+        POSEIDON_LOG_TRACE(("WebSocket data continuation: opcode = $1"), this->m_opcode);
+        break;
       }
-      break;
 
       case 8:  // close
       case 9:  // ping
@@ -552,8 +557,11 @@ parse_frame_header_from_stream(linear_buffer& data)
           this->m_error_desc = "control frame not fragmentable";
           return;
         }
+
+        // There shall be a message payload.
+        POSEIDON_LOG_TRACE(("WebSocket control frame: opcode = $1"), this->m_opcode);
+        break;
       }
-      break;
 
       default:
         // Reject this frame with an unknown opcode.
diff --git a/poseidon/http/websocket_frame_parser.hpp b/poseidon/http/websocket_frame_parser.hpp
index a9e9f7c6..05dbfc18 100644
--- a/poseidon/http/websocket_frame_parser.hpp
+++ b/poseidon/http/websocket_frame_parser.hpp
@@ -46,11 +46,11 @@ class WebSocket_Frame_Parser
         // 2
         WSF_State m_wsf;
         // 3
-        uint8_t m_msg_opcode : 4;
-        uint8_t m_msg_rsv3 : 1;
-        uint8_t m_msg_rsv2 : 1;
-        uint8_t m_msg_rsv1 : 1;
-        uint8_t m_msg_fin : 1;
+        uint8_t m_opcode : 4;
+        uint8_t m_rsv3 : 1;
+        uint8_t m_rsv2 : 1;
+        uint8_t m_rsv1 : 1;
+        uint8_t m_fin : 1;
       };
     };
 
@@ -179,23 +179,23 @@ class WebSocket_Frame_Parser
     // returned.
     bool
     message_fin() const noexcept
-      { return this->m_msg_fin;  }
+      { return this->m_fin;  }
 
     bool
     message_rsv1() const noexcept
-      { return this->m_msg_rsv1;  }
+      { return this->m_rsv1;  }
 
     bool
     message_rsv2() const noexcept
-      { return this->m_msg_rsv2;  }
+      { return this->m_rsv2;  }
 
     bool
     message_rsv3() const noexcept
-      { return this->m_msg_rsv3;  }
+      { return this->m_rsv3;  }
 
     uint8_t
     message_opcode() const noexcept
-      { return this->m_msg_opcode;  }
+      { return this->m_opcode;  }
 
     // Clears the current complete frame, so the parser can start the next one.
     void
diff --git a/poseidon/socket/ws_client_session.cpp b/poseidon/socket/ws_client_session.cpp
index c1db1ee7..1c3e64ca 100644
--- a/poseidon/socket/ws_client_session.cpp
+++ b/poseidon/socket/ws_client_session.cpp
@@ -182,14 +182,16 @@ do_on_http_upgraded_stream(linear_buffer& data, bool eof)
           switch(this->m_parser.frame_header().opcode) {
             case 0:  // CONTINUATION
             case 1:  // TEXT
-            case 2: {  // BINARY
+            case 2:  // BINARY
+            {
               auto opcode = static_cast<WebSocket_OpCode>(this->m_parser.message_opcode());
               ROCKET_ASSERT(is_any_of(opcode, { websocket_text, websocket_binary }));
               this->do_on_ws_message_finish(opcode, move(this->m_msg));
               break;
             }
 
-            case 8: {  // CLOSE
+            case 8:  // CLOSE
+            {
               ROCKET_ASSERT(this->m_closure_notified == false);
               this->m_closure_notified = true;
               data.clear();
@@ -199,7 +201,8 @@ do_on_http_upgraded_stream(linear_buffer& data, bool eof)
               return;
             }
 
-            case 9: {  // PING
+            case 9:  // PING
+            {
               POSEIDON_LOG_TRACE(("WebSocket PING from `$1`: $2"), this->remote_address(), payload);
               this->do_on_ws_message_finish(websocket_ping, move(payload));
 
@@ -208,7 +211,8 @@ do_on_http_upgraded_stream(linear_buffer& data, bool eof)
               break;
             }
 
-            case 10: {  // PONG
+            case 10:  // PONG
+            {
               POSEIDON_LOG_TRACE(("WebSocket PONG from `$1`: $2"), this->remote_address(), payload);
               this->do_on_ws_message_finish(websocket_pong, move(payload));
               break;
@@ -304,6 +308,7 @@ ws_send(WebSocket_OpCode opcode, chars_view data)
     switch(opcode) {
       case 1:  // TEXT
       case 2:  // BINARY
+      {
         // Check whether the message should be compressed. We believe that small
         // (including empty) messages are not worth compressing.
         if(this->m_pmce_opt) {
@@ -338,9 +343,11 @@ ws_send(WebSocket_OpCode opcode, chars_view data)
         // Send the message uncompressed.
         // FIN + opcode
         return this->do_ws_send_raw_frame(0b10000000 | opcode, data);
+      }
 
       case 9:  // PING
       case 10:  // PONG
+      {
         // Control messages can't be fragmented.
         if(data.n > 125)
           POSEIDON_THROW((
@@ -351,6 +358,7 @@ ws_send(WebSocket_OpCode opcode, chars_view data)
         // Control messages can't be compressed, so send it as is.
         // FIN + opcode
         return this->do_ws_send_raw_frame(0b10000000 | opcode, data);
+      }
 
       default:
         POSEIDON_THROW((
diff --git a/poseidon/socket/ws_server_session.cpp b/poseidon/socket/ws_server_session.cpp
index ad633bd4..9fb6df95 100644
--- a/poseidon/socket/ws_server_session.cpp
+++ b/poseidon/socket/ws_server_session.cpp
@@ -221,14 +221,16 @@ do_on_http_upgraded_stream(linear_buffer& data, bool eof)
           switch(this->m_parser.frame_header().opcode) {
             case 0:  // CONTINUATION
             case 1:  // TEXT
-            case 2: {  // BINARY
+            case 2:  // BINARY
+            {
               auto opcode = static_cast<WebSocket_OpCode>(this->m_parser.message_opcode());
               ROCKET_ASSERT(is_any_of(opcode, { websocket_text, websocket_binary }));
               this->do_on_ws_message_finish(opcode, move(this->m_msg));
               break;
             }
 
-            case 8: {  // CLOSE
+            case 8:  // CLOSE
+            {
               ROCKET_ASSERT(this->m_closure_notified == false);
               this->m_closure_notified = true;
               data.clear();
@@ -238,7 +240,8 @@ do_on_http_upgraded_stream(linear_buffer& data, bool eof)
               return;
             }
 
-            case 9: {  // PING
+            case 9:  // PING
+            {
               POSEIDON_LOG_TRACE(("WebSocket PING from `$1`: $2"), this->remote_address(), payload);
               this->do_on_ws_message_finish(websocket_ping, move(payload));
 
@@ -247,7 +250,8 @@ do_on_http_upgraded_stream(linear_buffer& data, bool eof)
               break;
             }
 
-            case 10: {  // PONG
+            case 10:  // PONG
+            {
               POSEIDON_LOG_TRACE(("WebSocket PONG from `$1`: $2"), this->remote_address(), payload);
               this->do_on_ws_message_finish(websocket_pong, move(payload));
               break;
@@ -338,6 +342,7 @@ ws_send(WebSocket_OpCode opcode, chars_view data)
     switch(opcode) {
       case 1:  // TEXT
       case 2:  // BINARY
+      {
         // Check whether the message should be compressed. We believe that small
         // (including empty) messages are not worth compressing.
         if(this->m_pmce_opt) {
@@ -372,9 +377,11 @@ ws_send(WebSocket_OpCode opcode, chars_view data)
         // Send the message uncompressed.
         // FIN + opcode
         return this->do_ws_send_raw_frame(0b10000000 | opcode, data);
+      }
 
       case 9:  // PING
       case 10:  // PONG
+      {
         // Control messages can't be fragmented.
         if(data.n > 125)
           POSEIDON_THROW((
@@ -385,6 +392,7 @@ ws_send(WebSocket_OpCode opcode, chars_view data)
         // Control messages can't be compressed, so send it as is.
         // FIN + opcode
         return this->do_ws_send_raw_frame(0b10000000 | opcode, data);
+      }
 
       default:
         POSEIDON_THROW((
diff --git a/poseidon/socket/wss_client_session.cpp b/poseidon/socket/wss_client_session.cpp
index c28cde0e..38f85b35 100644
--- a/poseidon/socket/wss_client_session.cpp
+++ b/poseidon/socket/wss_client_session.cpp
@@ -182,14 +182,16 @@ do_on_https_upgraded_stream(linear_buffer& data, bool eof)
           switch(this->m_parser.frame_header().opcode) {
             case 0:  // CONTINUATION
             case 1:  // TEXT
-            case 2: {  // BINARY
+            case 2:  // BINARY
+            {
               auto opcode = static_cast<WebSocket_OpCode>(this->m_parser.message_opcode());
               ROCKET_ASSERT(is_any_of(opcode, { websocket_text, websocket_binary }));
               this->do_on_wss_message_finish(opcode, move(this->m_msg));
               break;
             }
 
-            case 8: {  // CLOSE
+            case 8:  // CLOSE
+            {
               ROCKET_ASSERT(this->m_closure_notified == false);
               this->m_closure_notified = true;
               data.clear();
@@ -199,7 +201,8 @@ do_on_https_upgraded_stream(linear_buffer& data, bool eof)
               return;
             }
 
-            case 9: {  // PING
+            case 9:  // PING
+            {
               POSEIDON_LOG_TRACE(("WebSocket PING from `$1`: $2"), this->remote_address(), payload);
               this->do_on_wss_message_finish(websocket_ping, move(payload));
 
@@ -208,7 +211,8 @@ do_on_https_upgraded_stream(linear_buffer& data, bool eof)
               break;
             }
 
-            case 10: {  // PONG
+            case 10:  // PONG
+            {
               POSEIDON_LOG_TRACE(("WebSocket PONG from `$1`: $2"), this->remote_address(), payload);
               this->do_on_wss_message_finish(websocket_pong, move(payload));
               break;
@@ -304,6 +308,7 @@ wss_send(WebSocket_OpCode opcode, chars_view data)
     switch(opcode) {
       case 1:  // TEXT
       case 2:  // BINARY
+      {
         // Check whether the message should be compressed. We believe that small
         // (including empty) messages are not worth compressing.
         if(this->m_pmce_opt) {
@@ -338,9 +343,11 @@ wss_send(WebSocket_OpCode opcode, chars_view data)
         // Send the message uncompressed.
         // FIN + opcode
         return this->do_wss_send_raw_frame(0b10000000 | opcode, data);
+      }
 
       case 9:  // PING
       case 10:  // PONG
+      {
         // Control messages can't be fragmented.
         if(data.n > 125)
           POSEIDON_THROW((
@@ -351,6 +358,7 @@ wss_send(WebSocket_OpCode opcode, chars_view data)
         // Control messages can't be compressed, so send it as is.
         // FIN + opcode
         return this->do_wss_send_raw_frame(0b10000000 | opcode, data);
+      }
 
       default:
         POSEIDON_THROW((
diff --git a/poseidon/socket/wss_server_session.cpp b/poseidon/socket/wss_server_session.cpp
index e5c67984..44140f4a 100644
--- a/poseidon/socket/wss_server_session.cpp
+++ b/poseidon/socket/wss_server_session.cpp
@@ -221,14 +221,16 @@ do_on_https_upgraded_stream(linear_buffer& data, bool eof)
           switch(this->m_parser.frame_header().opcode) {
             case 0:  // CONTINUATION
             case 1:  // TEXT
-            case 2: {  // BINARY
+            case 2:  // BINARY
+            {
               auto opcode = static_cast<WebSocket_OpCode>(this->m_parser.message_opcode());
               ROCKET_ASSERT(is_any_of(opcode, { websocket_text, websocket_binary }));
               this->do_on_wss_message_finish(opcode, move(this->m_msg));
               break;
             }
 
-            case 8: {  // CLOSE
+            case 8:  // CLOSE
+            {
               ROCKET_ASSERT(this->m_closure_notified == false);
               this->m_closure_notified = true;
               data.clear();
@@ -238,7 +240,8 @@ do_on_https_upgraded_stream(linear_buffer& data, bool eof)
               return;
             }
 
-            case 9: {  // PING
+            case 9:  // PING
+            {
               POSEIDON_LOG_TRACE(("WebSocket PING from `$1`: $2"), this->remote_address(), payload);
               this->do_on_wss_message_finish(websocket_ping, move(payload));
 
@@ -247,7 +250,8 @@ do_on_https_upgraded_stream(linear_buffer& data, bool eof)
               break;
             }
 
-            case 10: {  // PONG
+            case 10:  // PONG
+            {
               POSEIDON_LOG_TRACE(("WebSocket PONG from `$1`: $2"), this->remote_address(), payload);
               this->do_on_wss_message_finish(websocket_pong, move(payload));
               break;