From 31d4d5d6bddb9eddb275b7415ad36866905a1660 Mon Sep 17 00:00:00 2001
From: Yedidya Feldblum <yfeldblum@fb.com>
Date: Wed, 4 Feb 2015 15:10:51 -0800
Subject: [PATCH] Avoid EventBase depending on Baton (mutex/condvar variant).

Summary: [Folly] Avoid EventBase depending on Baton (mutex/condvar variant).

Test Plan:
Unit tests:
* folly/io/async/test/EventBaseTest.cpp

Reviewed By: subodh@fb.com

Subscribers: trunkagent, fma, folly-diffs@, yfeldblum, dougw, brettp

FB internal diff: D1823407

Signature: t1:1823407:1423088450:71ae1673ed8067103e2aaa1ac9b239eae9ebe9de

Blame Revision: D1810764
---
 folly/io/async/EventBase.cpp | 31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

diff --git a/folly/io/async/EventBase.cpp b/folly/io/async/EventBase.cpp
index 00aa9d80..8ec54b67 100644
--- a/folly/io/async/EventBase.cpp
+++ b/folly/io/async/EventBase.cpp
@@ -20,12 +20,13 @@
 
 #include <folly/io/async/EventBase.h>
 
-#include <folly/Baton.h>
 #include <folly/ThreadName.h>
 #include <folly/io/async/NotificationQueue.h>
 
 #include <boost/static_assert.hpp>
+#include <condition_variable>
 #include <fcntl.h>
+#include <mutex>
 #include <pthread.h>
 #include <unistd.h>
 
@@ -570,12 +571,20 @@ bool EventBase::runInEventBaseThreadAndWait(void (*fn)(void*), void* arg) {
     return false;
   }
 
-  Baton<> ready;
+  bool ready = false;
+  std::mutex m;
+  std::condition_variable cv;
   runInEventBaseThread([&] {
+      SCOPE_EXIT {
+        std::unique_lock<std::mutex> l(m);
+        ready = true;
+        l.unlock();
+        cv.notify_one();
+      };
       fn(arg);
-      ready.post();
   });
-  ready.wait();
+  std::unique_lock<std::mutex> l(m);
+  cv.wait(l, [&] { return ready; });
 
   return true;
 }
@@ -587,12 +596,20 @@ bool EventBase::runInEventBaseThreadAndWait(const Cob& fn) {
     return false;
   }
 
-  Baton<> ready;
+  bool ready = false;
+  std::mutex m;
+  std::condition_variable cv;
   runInEventBaseThread([&] {
+      SCOPE_EXIT {
+        std::unique_lock<std::mutex> l(m);
+        ready = true;
+        l.unlock();
+        cv.notify_one();
+      };
       fn();
-      ready.post();
   });
-  ready.wait();
+  std::unique_lock<std::mutex> l(m);
+  cv.wait(l, [&] { return ready; });
 
   return true;
 }
-- 
2.34.1