[dxvk] Add new signal class

src/util/sync/sync_signal.h

@@ -0,0 +1,63 @@
+#pragma once
+
+#include <atomic>
+#include <condition_variable>
+#include <mutex>
+
+namespace dxvk::sync {
+  
+  /**
+   * \brief Signal
+   * 
+   * Acts as a simple CPU fence which can be signaled by one
+   * thread and waited upon by one more thread. Waiting on
+   * more than one thread is not supported.
+   */
+  class Signal : public RcObject {
+    
+  public:
+    
+    Signal()
+    : m_signaled(false) { }
+    Signal(bool signaled)
+    : m_signaled(signaled) { }
+    ~Signal() { }
+    
+    Signal             (const Signal&) = delete;
+    Signal& operator = (const Signal&) = delete;
+    
+    /**
+     * \brief Notifies signal
+     * Wakes any waiting thread.
+     */
+    void notify() {
+      std::lock_guard<std::mutex> lock(m_mutex);
+      m_signaled.store(true);
+      m_cond.notify_one();
+    }
+    
+    /**
+     * \brief Waits for signal
+     * 
+     * Blocks the calling thread until another
+     * thread wakes it up, then resets it to
+     * the non-signaled state.
+     */
+    void wait() {
+      if (!m_signaled.exchange(false)) {
+        std::unique_lock<std::mutex> lock(m_mutex);
+        m_cond.wait(lock, [this] {
+          return m_signaled.exchange(false);
+        });
+      }
+    }
+    
+  private:
+    
+    std::atomic<bool>       m_signaled;
+    std::mutex              m_mutex;
+    std::condition_variable m_cond;
+    
+  };
+  
+}