Mark getApplicationProtocol() const

Summary: getApplicationProtocol should probably be const.

Reviewed By: knekritz, mingtaoy

Differential Revision: D9772305

fbshipit-source-id: c648f9307214258639616e2f4ff3a90dfbf9484b

folly/io/async/AsyncSSLSocket.cpp

@@ -396,7 +396,7 @@ bool AsyncSSLSocket::connecting() const {
         (sslState_ == STATE_UNINIT || sslState_ == STATE_CONNECTING))));
 }
 
-std::string AsyncSSLSocket::getApplicationProtocol() noexcept {
+std::string AsyncSSLSocket::getApplicationProtocol() const noexcept {
   const unsigned char* protoName = nullptr;
   unsigned protoLength;
   if (getSelectedNextProtocolNoThrow(&protoName, &protoLength)) {

folly/io/async/AsyncSSLSocket.h

@@ -322,7 +322,7 @@ class AsyncSSLSocket : public virtual AsyncSocket {
   void shutdownWriteNow() override;
   bool good() const override;
   bool connecting() const override;
-  std::string getApplicationProtocol() noexcept override;
+  std::string getApplicationProtocol() const noexcept override;
 
   std::string getSecurityProtocol() const override {
     if (sslState_ == STATE_UNENCRYPTED) {

folly/io/async/AsyncTransport.h

@@ -411,7 +411,7 @@ class AsyncTransport : public DelayedDestruction, public AsyncSocketBase {
    * protocol. This is useful for transports which are used to tunnel other
    * protocols.
    */
-  virtual std::string getApplicationProtocol() noexcept {
+  virtual std::string getApplicationProtocol() const noexcept {
     return "";
   }
 

folly/io/async/DecoratedAsyncTransportWrapper.h

@@ -172,7 +172,7 @@ class DecoratedAsyncTransportWrapper : public folly::AsyncTransportWrapper {
     transport_->shutdownWriteNow();
   }
 
-  std::string getApplicationProtocol() noexcept override {
+  std::string getApplicationProtocol() const noexcept override {
     return transport_->getApplicationProtocol();
   }