From ff0a859ceb6f6f0a41e5b6100bf60e7b23904374 Mon Sep 17 00:00:00 2001
From: Quantum <quantum2048@gmail.com>
Date: Sat, 30 Jan 2021 19:12:42 -0500
Subject: [PATCH] [host] nvfbc: avoid recreating mouse hook and 1x1 window

The mouse hook code is very fragile, and we would like to avoid unhooking
and re-hooking as much as possible.

After this commit, this is done only once, and the hook and 1x1 window is
only destroyed upon exit. This, of course, comes with the downside of
the slight performance penalty if the guest machine is used directly while
the host is running and the client is not running.
---
 .../Windows/capture/NVFBC/src/nvfbc.c         | 25 +++++++++++++++----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/host/platform/Windows/capture/NVFBC/src/nvfbc.c b/host/platform/Windows/capture/NVFBC/src/nvfbc.c
index 4c3947da..562bfdd3 100644
--- a/host/platform/Windows/capture/NVFBC/src/nvfbc.c
+++ b/host/platform/Windows/capture/NVFBC/src/nvfbc.c
@@ -61,6 +61,9 @@ struct iface
 
   int mouseX, mouseY, mouseHotX, mouseHotY;
   bool mouseVisible, hasMousePosition;
+
+  bool mouseHookCreated;
+  bool forceCompositionCreated;
 };
 
 static struct iface * this = NULL;
@@ -188,12 +191,21 @@ static bool nvfbc_init(void)
   }
 
   this->cursorEvents[0] = lgCreateEvent(true, 10);
-  mouseHook_install(on_mouseMove);
 
   if (this->seperateCursor)
     this->cursorEvents[1] = lgWrapEvent(event);
 
-  dwmForceComposition();
+  if (!this->mouseHookCreated)
+  {
+    mouseHook_install(on_mouseMove);
+    this->mouseHookCreated = true;
+  }
+
+  if (!this->forceCompositionCreated)
+  {
+    dwmForceComposition();
+    this->forceCompositionCreated = true;
+  }
 
   DEBUG_INFO("Cursor mode      : %s", this->seperateCursor ? "decoupled" : "integrated");
 
@@ -226,9 +238,6 @@ static void nvfbc_stop(void)
 
 static bool nvfbc_deinit(void)
 {
-  mouseHook_remove();
-  dwmUnforceComposition();
-
   if (this->cursorEvents[0])
   {
     lgFreeEvent(this->cursorEvents[0]);
@@ -249,6 +258,12 @@ static void nvfbc_free(void)
   if (this->frameEvent)
     lgFreeEvent(this->frameEvent);
 
+  if (this->mouseHookCreated)
+    mouseHook_remove();
+
+  if (this->forceCompositionCreated)
+    dwmUnforceComposition();
+
   free(this);
   this = NULL;
   NvFBCFree();