Rename some acceptor methods to reflect what they actually do

Summary: Also factor out the state transition to Drained into a method.

Reviewed By: HsiehYuho

Differential Revision: D48693967

fbshipit-source-id: c888b637cb4b1200035f7c4929151b5c47280074

wangle/acceptor/Acceptor.cpp

@@ -249,7 +249,7 @@ void Acceptor::setTLSTicketSecrets(
   }
 }
 
-void Acceptor::drainAllConnections() {
+void Acceptor::startDrainingAllConnections() {
   if (downstreamConnectionManager_) {
     downstreamConnectionManager_->initiateGracefulShutdown(
         gracefulShutdownTimeout_);
@@ -507,15 +507,15 @@ void Acceptor::sslConnectionReady(
   connectionReady(
       std::move(sock), clientAddr, nextProtocol, secureTransportType, tinfo);
   if (state_ == State::kDraining) {
-    checkDrained();
+    checkIfDrained();
   }
 }
 
 void Acceptor::sslConnectionError(const folly::exception_wrapper&) {
   CHECK(numPendingSSLConns_ > 0);
   --numPendingSSLConns_;
   if (state_ == State::kDraining) {
-    checkDrained();
+    checkIfDrained();
   }
 }
 
@@ -531,27 +531,27 @@ void Acceptor::acceptError(const std::exception& ex) noexcept {
 void Acceptor::acceptStopped() noexcept {
   VLOG(3) << "Acceptor " << this << " acceptStopped()";
   // Drain the open client connections
-  drainAllConnections();
+  startDrainingAllConnections();
 
   // If we haven't yet finished draining, begin doing so by marking ourselves
-  // as in the draining state. We must be sure to hit checkDrained() here, as
+  // as in the draining state. We must be sure to hit checkIfDrained() here, as
   // if we're completely idle, we can should consider ourself drained
   // immediately (as there is no outstanding work to complete to cause us to
   // re-evaluate this).
   if (state_ != State::kDone) {
     state_ = State::kDraining;
-    checkDrained();
+    checkIfDrained();
   }
 }
 
 void Acceptor::onEmpty(const ConnectionManager&) {
   VLOG(3) << "Acceptor=" << this << " onEmpty()";
   if (state_ == State::kDraining) {
-    checkDrained();
+    checkIfDrained();
   }
 }
 
-void Acceptor::checkDrained() {
+void Acceptor::checkIfDrained() {
   CHECK(state_ == State::kDraining);
   if (forceShutdownInProgress_ || !downstreamConnectionManager_ ||
       (downstreamConnectionManager_->getNumConnections() != 0) ||
@@ -563,10 +563,7 @@ void Acceptor::checkDrained() {
           << base_;
 
   downstreamConnectionManager_.reset();
-
-  state_ = State::kDone;
-
-  onConnectionsDrained();
+  transitionToDrained();
 }
 
 void Acceptor::drainConnections(double pctToDrain) {
@@ -605,8 +602,7 @@ void Acceptor::dropAllConnections() {
   }
   CHECK(numPendingSSLConns_ == 0);
 
-  state_ = State::kDone;
-  onConnectionsDrained();
+  transitionToDrained();
 }
 
 void Acceptor::dropConnections(double pctToDrop) {

wangle/acceptor/Acceptor.h

@@ -192,7 +192,7 @@ class Acceptor : public folly::AsyncServerSocket::AcceptCallback,
   }
 
   /**
-   * Time after drainAllConnections() or acceptStopped() during which
+   * Time after startDrainingAllConnections() or acceptStopped() during which
    * new requests on connections owned by the downstream
    * ConnectionManager will be processed normally.
    */
@@ -253,10 +253,11 @@ class Acceptor : public folly::AsyncServerSocket::AcceptCallback,
       TransportInfo& tinfo) noexcept;
 
   /**
-   * Drains all open connections of their outstanding transactions. When
-   * a connection's transaction count reaches zero, the connection closes.
+   * Starts draining all open connections of their outstanding transactions
+   * asynchronously. When a connection's transaction count reaches zero, the
+   * connection closes.
    */
-  virtual void drainAllConnections();
+  virtual void startDrainingAllConnections();
 
   /**
    * Drain defined percentage of connections.
@@ -539,14 +540,19 @@ class Acceptor : public folly::AsyncServerSocket::AcceptCallback,
   folly::AsyncTransport::UniquePtr transformTransport(
       folly::AsyncTransport::UniquePtr sock);
 
+  void transitionToDrained() {
+    state_ = State::kDone;
+    onConnectionsDrained();
+  }
+
   TLSTicketKeySeeds ticketSecrets_;
   std::shared_ptr<fizz::server::CertManager> fizzCertManager_{nullptr};
 
   // Forbidden copy constructor and assignment opererator
   Acceptor(Acceptor const&) = delete;
   Acceptor& operator=(Acceptor const&) = delete;
 
-  void checkDrained();
+  void checkIfDrained();
 
   State state_{State::kInit};
   uint64_t numPendingSSLConns_{0};