From 27304354844c8baf8c14ef923e0ab65bc4df2dc0 Mon Sep 17 00:00:00 2001
From: Determinant <ted.sybil@gmail.com>
Date: Wed, 21 Nov 2018 18:15:14 -0500
Subject: impl MPMCQueueEventDriven

---
 include/salticidae/event.h | 51 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

(limited to 'include')

diff --git a/include/salticidae/event.h b/include/salticidae/event.h
index bac707c..649cfdd 100644
--- a/include/salticidae/event.h
+++ b/include/salticidae/event.h
@@ -589,6 +589,57 @@ class MPSCQueueEventDriven: public MPSCQueue<T> {
     }
 };
 
+template<typename T>
+class MPMCQueueEventDriven: public MPMCQueue<T> {
+    private:
+    const uint64_t dummy = 1;
+    std::atomic<bool> wait_sig;
+    int fd;
+    std::vector<FdEvent> evs;
+
+    public:
+    MPMCQueueEventDriven(size_t capacity = 65536):
+        MPMCQueue<T>(capacity),
+        wait_sig(true),
+        fd(eventfd(0, EFD_NONBLOCK)) {}
+
+    ~MPMCQueueEventDriven() {
+        evs.clear();
+        close(fd);
+    }
+
+    // this function is *NOT* thread-safe
+    template<typename Func>
+    void reg_handler(const EventContext &ec, Func &&func) {
+        FdEvent ev(ec, fd, [this, func=std::forward<Func>(func)](int, int) {
+            //fprintf(stderr, "%x\n", std::this_thread::get_id());
+            uint64_t t;
+            if (read(fd, &t, 8) != 8) return;
+            // only one consumer should be here a a time
+            wait_sig.store(true, std::memory_order_release);
+            if (func(*this))
+                write(fd, &dummy, 8);
+        });
+        ev.add(FdEvent::READ);
+        evs.push_back(std::move(ev));
+    }
+
+    void unreg_handlers() { evs.clear(); }
+
+    template<typename U>
+    bool enqueue(U &&e) {
+        static const uint64_t dummy = 1;
+        bool ret = MPMCQueue<T>::enqueue(std::forward<U>(e));
+        // memory barrier here, so any load/store in enqueue must be finialized
+        if (wait_sig.exchange(false, std::memory_order_acq_rel))
+        {
+            SALTICIDAE_LOG_DEBUG("mpsc notify");
+            write(fd, &dummy, 8);
+        }
+        return ret;
+    }
+};
+
 }
 
 #endif
-- 
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