[host] windows: detect whether screensaver is disabled in the guest

This will allow us to add an option to disable the screensaver on the client
when an application in the guest requests it. This behaviour may be useful
when the guest is doing media playback.

common/include/common/KVMFR.h

@@ -23,10 +23,11 @@ Place, Suite 330, Boston, MA 02111-1307 USA
 #pragma once
 
 #include <stdint.h>
+#include <stdbool.h>
 #include "types.h"
 
 #define KVMFR_MAGIC   "KVMFR---"
-#define KVMFR_VERSION 8
+#define KVMFR_VERSION 9
 
 #define LGMP_Q_POINTER     1
 #define LGMP_Q_FRAME       2
@@ -73,6 +74,7 @@ typedef struct KVMFRFrame
   uint32_t      pitch;             // the row pitch  (stride in bytes or the compressed frame size)
   uint32_t      offset;            // offset from the start of this header to the FrameBuffer header
   uint32_t      mouseScalePercent; // movement scale factor of the mouse (relates to DPI of display, 100 = no scale)
+  bool          blockScreensaver;  // whether the guest has requested to block screensavers
 }
 KVMFRFrame;
 

host/include/interface/platform.h

@@ -38,3 +38,5 @@ void app_quit();
 // these must be implemented for each OS
 const char * os_getExecutable();
 const char * os_getDataPath();
+
+bool os_blockScreensaver();

host/platform/Linux/src/platform.c

@@ -72,3 +72,8 @@ const char * os_getDataPath(void)
 {
   return app.dataPath;
 }
+
+bool os_blockScreensaver()
+{
+  return false;
+}

host/platform/Windows/CMakeLists.txt

@@ -33,6 +33,7 @@ target_link_libraries(platform_Windows
 	wtsapi32
 	psapi
 	shlwapi
+	powrprof
 )
 
 target_include_directories(platform_Windows

host/platform/Windows/src/platform.c

@@ -25,6 +25,8 @@ Place, Suite 330, Boston, MA 02111-1307 USA
 #include <shellapi.h>
 #include <shlwapi.h>
 #include <fcntl.h>
+#include <powrprof.h>
+#include <ntstatus.h>
 
 #include "interface/platform.h"
 #include "common/debug.h"
@@ -397,3 +399,24 @@ HWND os_getMessageWnd(void)
 {
   return app.messageWnd;
 }
+
+bool os_blockScreensaver()
+{
+  static bool      lastResult = false;
+  static ULONGLONG lastCheck  = 0;
+
+  ULONGLONG now = GetTickCount64();
+  if (now - lastCheck >= 1000)
+  {
+    ULONG executionState;
+    NTSTATUS status = CallNtPowerInformation(SystemExecutionState, NULL, 0,
+      &executionState, sizeof executionState);
+
+    if (status == STATUS_SUCCESS)
+      lastResult = executionState & ES_DISPLAY_REQUIRED;
+    else
+      DEBUG_ERROR("Failed to call CallNtPowerInformation(SystemExecutionState): %ld", status);
+    lastCheck = now;
+  }
+  return lastResult;
+}

host/src/app.c

@@ -206,6 +206,7 @@ static int frameThread(void * opaque)
     fi->pitch             = frame.pitch;
     fi->offset            = pageSize - FrameBufferStructSize;
     fi->mouseScalePercent = app.iface->getMouseScale();
+    fi->blockScreensaver  = os_blockScreensaver();
     frameValid            = true;
 
     // put the framebuffer on the border of the next page