clientbootstrap.patch

diff --git a/wangle/bootstrap/ClientBootstrap.h b/wangle/bootstrap/ClientBootstrap.h
index b9a4153..6787288 100644
--- a/wangle/bootstrap/ClientBootstrap.h
+++ b/wangle/bootstrap/ClientBootstrap.h
@@ -82,6 +82,7 @@ class ClientBootstrap {
     if (group_) {
       base = group_->getEventBase();
     }
+    base_ = base;
     folly::Future<Pipeline*> retval((Pipeline*)nullptr);
     base->runImmediatelyOrRunInEventBaseThreadAndWait([&](){
       std::shared_ptr<folly::AsyncSocket> socket;
@@ -105,6 +106,35 @@ class ClientBootstrap {
     return retval;
   }
 
+  folly::Future<Pipeline*> reconnect(
+      const folly::SocketAddress& address,
+      std::chrono::milliseconds timeout = std::chrono::milliseconds(0)) {
+    DCHECK(pipelineFactory_);
+    DCHECK(base_);
+    folly::Future<Pipeline*> retval((Pipeline*)nullptr);
+    base_->runImmediatelyOrRunInEventBaseThreadAndWait([&](){
+      std::shared_ptr<folly::AsyncSocket> socket;
+      if (sslContext_) {
+        auto sslSocket = folly::AsyncSSLSocket::newSocket(sslContext_, base_);
+        if (sslSession_) {
+          sslSocket->setSSLSession(sslSession_, true);
+        }
+        socket = sslSocket;
+      } else {
+        socket = folly::AsyncSocket::newSocket(base_);
+      }
+      folly::Promise<Pipeline*> promise;
+      retval = promise.getFuture();
+      socket->connect(
+          new ConnectCallback(std::move(promise), this),
+          address,
+          timeout.count());
+      pipeline_ = pipelineFactory_->newPipeline(socket);
+    });
+    return retval;
+  }
+
+
   ClientBootstrap* pipelineFactory(
       std::shared_ptr<PipelineFactory<Pipeline>> factory) {
     pipelineFactory_ = factory;
@@ -115,7 +145,17 @@ class ClientBootstrap {
     return pipeline_.get();
   }
 
-  virtual ~ClientBootstrap() = default;
+  virtual ~ClientBootstrap() {
+    if (base_ && group_.get() && pipeline_) {
+      // Pipeline was already created, destroy from the EventBase thread
+      // as AsyncSocket destruct could only be called from its EventBase thread
+      VLOG(5) << " ~ClientBootstrap " << this 
+        << ", destruct pipeline_ in EventBase thread";
+      base_->runImmediatelyOrRunInEventBaseThreadAndWait([&](){
+        pipeline_.reset();
+      });
+    }
+  };
 
  protected:
   typename Pipeline::Ptr pipeline_;
@@ -124,6 +164,11 @@ class ClientBootstrap {
 
   std::shared_ptr<PipelineFactory<Pipeline>> pipelineFactory_;
   std::shared_ptr<wangle::IOThreadPoolExecutor> group_;
+  // This is for the reconnect case to use the same EventBase.
+  // So the old pipeline_ could be destroyed by the same EventBase thread.
+  // TODO is there any way to get EventBase from pipeline_?
+  //      AsyncSocket has getEventBase() func.
+  folly::EventBase* base_{nullptr};
   folly::SSLContextPtr sslContext_;
   SSL_SESSION* sslSession_{nullptr};
 };