[dxvk] Add DxvkEvent class

Will be used to back D3D11 event queries.

src/dxvk/dxvk_event.cpp

@@ -0,0 +1,32 @@
+#include "dxvk_event.h"
+
+namespace dxvk {
+  
+  DxvkEvent:: DxvkEvent() { }
+  DxvkEvent::~DxvkEvent() { }
+  
+  
+  uint32_t DxvkEvent::reset() {
+    std::unique_lock<std::mutex> lock(m_mutex);
+    
+    m_status = DxvkEventStatus::Reset;
+    return ++m_revision;
+  }
+  
+  
+  void DxvkEvent::signalEvent(uint32_t revision) {
+    std::unique_lock<std::mutex> lock(m_mutex);
+    
+    if (m_revision == revision) {
+      m_status = DxvkEventStatus::Signaled;
+      m_signal.notify_one();
+    }
+  }
+  
+  
+  DxvkEventStatus DxvkEvent::getStatus() {
+    std::unique_lock<std::mutex> lock(m_mutex);
+    return m_status;
+  }
+  
+}

src/dxvk/dxvk_event.h

@@ -0,0 +1,57 @@
+#pragma once
+
+#include <condition_variable>
+#include <mutex>
+
+#include "dxvk_include.h"
+
+namespace dxvk {
+  
+  enum class DxvkEventStatus {
+    Reset     = 0,
+    Signaled  = 1,
+  };
+  
+  /**
+   * \brief Event
+   * 
+   * A CPU-side fence that will be signaled after
+   * all previous Vulkan commands recorded to a
+   * command buffer have finished executing.
+   */
+  class DxvkEvent : public RcObject {
+    
+  public:
+    
+    DxvkEvent();
+    ~DxvkEvent();
+    
+    /**
+     * \brief Resets the event
+     * \returns New revision ID
+     */
+    uint32_t reset();
+    
+    /**
+     * \brief Signals the event
+     * \param [in] revision The revision ID
+     */
+    void signalEvent(uint32_t revision);
+    
+    /**
+     * \brief Queries event status
+     * \returns Current event status
+     */
+    DxvkEventStatus getStatus();
+    
+  private:
+    
+    std::mutex              m_mutex;
+    std::condition_variable m_signal;
+    
+    DxvkEventStatus         m_status   = DxvkEventStatus::Reset;
+    uint32_t                m_revision = 0;
+    
+  };
+  
+}