module core.sync.event2 added

druntime/src/core/sync/event2.d

@@ -0,0 +1,123 @@
+/**
+ * The event module provides a primitive for lightweight signaling of other threads
+ * (emulating Windows events on Posix)
+ *
+ * Copyright: Copyright (c) 2019 D Language Foundation
+ * License: Distributed under the
+ *    $(LINK2 http://www.boost.org/LICENSE_1_0.txt, Boost Software License 1.0).
+ *    (See accompanying file LICENSE)
+ */
+module core.sync.event2;
+
+import core.time;
+
+struct Event2
+{
+nothrow @nogc:
+    /**
+     * Creates an event object.
+     *
+     * Params:
+     *  manualReset  = the state of the event is not reset automatically after resuming waiting clients
+     *  initialState = initial state of the signal
+     */
+    this(bool manualReset, bool initialState)
+    {
+        osEvent = OsEvent(manualReset, initialState);
+    }
+
+    // copying not allowed, can produce resource leaks
+    @disable this(this);
+    @disable void opAssign(Event2);
+
+    /// Set the event to "signaled", so that waiting clients are resumed
+    void set()
+    {
+        osEvent.set();
+    }
+
+    /// Reset the event manually
+    void reset()
+    {
+        osEvent.reset();
+    }
+
+    /**
+     * Wait for the event to be signaled without timeout.
+     *
+     * Returns:
+     *  `true` if the event is in signaled state, `false` if the event is uninitialized or another error occured
+     */
+    bool wait()
+    {
+        return osEvent.wait();
+    }
+
+    /**
+     * Wait for the event to be signaled with timeout.
+     *
+     * Params:
+     *  tmout = the maximum time to wait
+     * Returns:
+     *  `true` if the event is in signaled state, `false` if the event was nonsignaled for the given time or
+     *  the event is uninitialized or another error occured
+     */
+    bool wait(Duration tmout)
+    {
+        return osEvent.wait(tmout);
+    }
+
+private:
+    import rt.sys.config;
+
+    mixin("import " ~ osEventImport ~ ";");
+    OsEvent osEvent;
+}
+
+// Test single-thread (non-shared) use.
+@nogc nothrow unittest
+{
+    // auto-reset, initial state false
+    Event2 ev1 = Event2(false, false);
+    assert(!ev1.wait(1.dur!"msecs"));
+    ev1.set();
+    assert(ev1.wait());
+    assert(!ev1.wait(1.dur!"msecs"));
+
+    // manual-reset, initial state true
+    Event ev2 = Event(true, true);
+    assert(ev2.wait());
+    assert(ev2.wait());
+    ev2.reset();
+    assert(!ev2.wait(1.dur!"msecs"));
+}
+
+unittest
+{
+    import core.thread, core.atomic;
+
+    scope event      = new Event2(true, false);
+    int  numThreads = 10;
+    shared int numRunning = 0;
+
+    void testFn()
+    {
+        event.wait(8.dur!"seconds"); // timeout below limit for druntime test_runner
+        numRunning.atomicOp!"+="(1);
+    }
+
+    auto group = new ThreadGroup;
+
+    for (int i = 0; i < numThreads; ++i)
+        group.create(&testFn);
+
+    auto start = MonoTime.currTime;
+    assert(numRunning == 0);
+
+    event.set();
+    group.joinAll();
+
+    assert(numRunning == numThreads);
+
+    assert(MonoTime.currTime - start < 5.dur!"seconds");
+}