Add logs for TFO succeded

[folly.git] / folly / io / async / EventBase.cpp

diff --git a/folly/io/async/EventBase.cpp b/folly/io/async/EventBase.cpp
index 2680d96cd90fb5d4368753fa28689f726cebff1e..a4cbfa2055724c6c94166ffa98f4db3f2e6734db 100644 (file)
--- a/folly/io/async/EventBase.cpp
+++ b/folly/io/async/EventBase.cpp
@@ -198,7 +198,7 @@ EventBase::~EventBase() {
   // Keep looping until all keep-alive handles are released. Each keep-alive
   // handle signals that some external code will still schedule some work on
   // this EventBase (so it's not safe to destroy it).
-  while (!loopKeepAlive_.unique()) {
+  while (loopKeepAliveCount_ > 0) {
     applyLoopKeepAlive();
     loopOnce();
   }
@@ -223,7 +223,7 @@ EventBase::~EventBase() {
     delete &runBeforeLoopCallbacks_.front();
   }
 
-  (void) runLoopCallbacks(false);
+  (void)runLoopCallbacks();
 
   if (!fnRunner_->consumeUntilDrained()) {
     LOG(ERROR) << "~EventBase(): Unable to drain notification queue";
@@ -236,12 +236,6 @@ EventBase::~EventBase() {
     event_base_free(evb_);
   }
 
-  while (!runAfterDrainCallbacks_.empty()) {
-    LoopCallback* callback = &runAfterDrainCallbacks_.front();
-    runAfterDrainCallbacks_.pop_front();
-    callback->runLoopCallback();
-  }
-
   {
     std::lock_guard<std::mutex> lock(localStorageMutex_);
     for (auto storage : localStorageToDtor_) {
@@ -303,6 +297,19 @@ bool EventBase::loopOnce(int flags) {
 
 bool EventBase::loopBody(int flags) {
   VLOG(5) << "EventBase(): Starting loop.";
+
+  DCHECK(!invokingLoop_)
+      << "Your code just tried to loop over an event base from inside another "
+      << "event base loop. Since libevent is not reentrant, this leads to "
+      << "undefined behavior in opt builds. Please fix immediately. For the "
+      << "common case of an inner function that needs to do some synchronous "
+      << "computation on an event-base, replace getEventBase() by a new, "
+      << "stack-allocated EvenBase.";
+  invokingLoop_ = true;
+  SCOPE_EXIT {
+    invokingLoop_ = false;
+  };
+
   int res = 0;
   bool ranLoopCallbacks;
   bool blocking = !(flags & EVLOOP_NONBLOCK);
@@ -435,12 +442,12 @@ bool EventBase::loopBody(int flags) {
 }
 
 void EventBase::applyLoopKeepAlive() {
-  if (loopKeepAliveActive_ && loopKeepAlive_.unique()) {
+  if (loopKeepAliveActive_ && loopKeepAliveCount_ == 0) {
     // Restore the notification queue internal flag
     fnRunner_->stopConsuming();
     fnRunner_->startConsumingInternal(this, queue_.get());
     loopKeepAliveActive_ = false;
-  } else if (!loopKeepAliveActive_ && !loopKeepAlive_.unique()) {
+  } else if (!loopKeepAliveActive_ && loopKeepAliveCount_ > 0) {
     // Update the notification queue event to treat it as a normal
     // (non-internal) event.  The notification queue event always remains
     // installed, and the main loop won't exit with it installed.
@@ -455,11 +462,9 @@ void EventBase::loopForever() {
   {
     SCOPE_EXIT {
       applyLoopKeepAlive();
-      loopForeverActive_ = false;
     };
-    loopForeverActive_ = true;
     // Make sure notification queue events are treated as normal events.
-    auto loopKeepAlive = loopKeepAlive_;
+    auto keepAlive = loopKeepAlive();
     ret = loop();
   }
 
@@ -538,13 +543,6 @@ void EventBase::runInLoop(Func cob, bool thisIteration) {
   }
 }
 
-void EventBase::runAfterDrain(Func cob) {
-  auto callback = new FunctionLoopCallback(std::move(cob));
-  std::lock_guard<std::mutex> lg(runAfterDrainCallbacksMutex_);
-  callback->cancelLoopCallback();
-  runAfterDrainCallbacks_.push_back(*callback);
-}
-
 void EventBase::runOnDestruction(LoopCallback* callback) {
   std::lock_guard<std::mutex> lg(onDestructionCallbacksMutex_);
   callback->cancelLoopCallback();
@@ -645,7 +643,7 @@ bool EventBase::tryRunAfterDelay(
   return true;
 }
 
-bool EventBase::runLoopCallbacks(bool setContext) {
+bool EventBase::runLoopCallbacks() {
   if (!loopCallbacks_.empty()) {
     bumpHandlingTime();
     // Swap the loopCallbacks_ list with a temporary list on our stack.
@@ -663,9 +661,7 @@ bool EventBase::runLoopCallbacks(bool setContext) {
     while (!currentCallbacks.empty()) {
       LoopCallback* callback = &currentCallbacks.front();
       currentCallbacks.pop_front();
-      if (setContext) {
-        RequestContext::setContext(callback->context_);
-      }
+      folly::RequestContextScopeGuard rctx(callback->context_);
       callback->runLoopCallback();
     }