Use recursive_mutex in blaze.cc instead of mutex.
This is necessary because a SIGINT can strike at any time, including when the main thread holds the mutex.
--
MOS_MIGRATED_REVID=120816015
diff --git a/src/main/cpp/blaze.cc b/src/main/cpp/blaze.cc
index 2c1eeb3..0e678af 100644
--- a/src/main/cpp/blaze.cc
+++ b/src/main/cpp/blaze.cc
@@ -164,9 +164,15 @@
std::string response_cookie_;
std::string command_id_;
- std::condition_variable cancel_thread_signal_;
- // protects command_id_ and cancel_thread_action_
- std::mutex cancel_thread_mutex_;
+ // The mutex is locked only once in the cancel thread (the only place where
+ // we call .wait()), so it's okay to use a condition variable with a
+ // recursive mutex.
+ std::condition_variable_any cancel_thread_signal_;
+
+ // protects command_id_ and cancel_thread_action_ Needs to be recursive so
+ // that there is no deadlock if the main thread receives a SIGINT while the
+ // mutex is locked.
+ std::recursive_mutex cancel_thread_mutex_;
CancelThreadAction cancel_thread_action_;
void CancelThread();
@@ -1924,7 +1930,7 @@
// delivered to the server)
void GrpcBlazeServer::CancelThread() {
bool running = true;
- std::unique_lock<std::mutex> lock(cancel_thread_mutex_);
+ std::unique_lock<std::recursive_mutex> lock(cancel_thread_mutex_);
while (running) {
cancel_thread_signal_.wait(lock);
switch (cancel_thread_action_) {
@@ -1998,7 +2004,7 @@
client_->Run(&context, request));
{
- std::unique_lock<std::mutex> lock(cancel_thread_mutex_);
+ std::unique_lock<std::recursive_mutex> lock(cancel_thread_mutex_);
cancel_thread_action_ = NOTHING;
}
@@ -2021,7 +2027,7 @@
}
if (!command_id_set && response.command_id().size() > 0) {
- std::unique_lock<std::mutex> lock(cancel_thread_mutex_);
+ std::unique_lock<std::recursive_mutex> lock(cancel_thread_mutex_);
command_id_ = response.command_id();
command_id_set = true;
// Wake up the cancellation thread in case there is a pending cancellation
@@ -2031,7 +2037,7 @@
{
// Wake up the cancellation thread so that it can finish
- std::unique_lock<std::mutex> lock(cancel_thread_mutex_);
+ std::unique_lock<std::recursive_mutex> lock(cancel_thread_mutex_);
cancel_thread_action_ = JOIN;
cancel_thread_signal_.notify_one();
}
@@ -2052,7 +2058,7 @@
}
void GrpcBlazeServer::Cancel() {
- std::unique_lock<std::mutex> lock(cancel_thread_mutex_);
+ std::unique_lock<std::recursive_mutex> lock(cancel_thread_mutex_);
// Wake up the cancellation thread and tell it to issue its RPC
cancel_thread_action_ = CANCEL;
cancel_thread_signal_.notify_one();
