refactor: rename EventLoop::m_num_clients to m_num_refs

include/mp/proxy-io.h

@@ -255,7 +255,7 @@ class EventLoop
 
     //! Run event loop. Does not return until shutdown. This should only be
     //! called once from the m_thread_id thread. This will block until
-    //! the m_num_clients reference count is 0.
+    //! the m_num_refs reference count is 0.
     void loop();
 
     //! Run function on event loop thread. Does not return until function completes.
@@ -314,9 +314,13 @@ class EventLoop
     //! Pipe write handle used to wake up the event loop thread.
     int m_post_fd = -1;
 
-    //! Number of clients holding references to ProxyServerBase objects that
-    //! reference this event loop.
-    int m_num_clients MP_GUARDED_BY(m_mutex) = 0;
+    //! Number of EventLoopRef instances referencing this event loop. This is a
+    //! sum of the number of client and server objects (Connection, ProxyClient,
+    //! ProxyServer) using the loop, plus temporary references held while
+    //! posting functions to the loop, plus any references held by external code
+    //! to keep the loop running. The loop() method exits when this count drops
+    //! to 0 (and m_async_fns is empty).
+    int m_num_refs MP_GUARDED_BY(m_mutex) = 0;
 
     //! Mutex and condition variable used to post tasks to event loop and async
     //! thread.

include/mp/proxy.h

@@ -44,7 +44,7 @@ inline void CleanupRun(CleanupList& fns) {
     }
 }
 
-//! Event loop smart pointer automatically managing m_num_clients.
+//! Event loop smart pointer automatically managing m_num_refs.
 //! If a lock pointer argument is passed, the specified lock will be used,
 //! otherwise EventLoop::m_mutex will be locked when needed.
 class EventLoopRef

src/mp/proxy.cpp

@@ -51,7 +51,7 @@ EventLoopRef::EventLoopRef(EventLoop& loop, Lock* lock) : m_loop(&loop), m_lock(
 {
     auto loop_lock{PtrOrValue{m_lock, m_loop->m_mutex}};
     loop_lock->assert_locked(m_loop->m_mutex);
-    m_loop->m_num_clients += 1;
+    m_loop->m_num_refs += 1;
 }
 
 // Due to the conditionals in this function, MP_NO_TSA is required to avoid
@@ -63,8 +63,8 @@ void EventLoopRef::reset(bool relock) MP_NO_TSA
         m_loop = nullptr;
         auto loop_lock{PtrOrValue{m_lock, loop->m_mutex}};
         loop_lock->assert_locked(loop->m_mutex);
-        assert(loop->m_num_clients > 0);
-        loop->m_num_clients -= 1;
+        assert(loop->m_num_refs > 0);
+        loop->m_num_refs -= 1;
         if (loop->done()) {
             loop->m_cv.notify_all();
             int post_fd{loop->m_post_fd};
@@ -218,7 +218,7 @@ EventLoop::~EventLoop()
     KJ_ASSERT(!m_async_fns);
     KJ_ASSERT(m_wait_fd == -1);
     KJ_ASSERT(m_post_fd == -1);
-    KJ_ASSERT(m_num_clients == 0);
+    KJ_ASSERT(m_num_refs == 0);
 
     // Spin event loop. wait for any promises triggered by RPC shutdown.
     // auto cleanup = kj::evalLater([]{});
@@ -320,8 +320,8 @@ void EventLoop::startAsyncThread()
 
 bool EventLoop::done() const
 {
-    assert(m_num_clients >= 0);
-    return m_num_clients == 0 && m_async_fns->empty();
+    assert(m_num_refs >= 0);
+    return m_num_refs == 0 && m_async_fns->empty();
 }
 
 std::tuple<ConnThread, bool> SetThread(GuardedRef<ConnThreads> threads, Connection* connection, const std::function<Thread::Client()>& make_thread)