[PATCH v2 1/1] win32u: Initialize the server's cursor position from the user driver's.

[Tim Clem]

From: Tim Clem

Until the user moves the mouse, the server's idea of the cursor
position is likely incorrect. Very early in the lifespan of a user
driver (after desktop creation), sync the server with the result of
the driver's GetCursorPos.
---
 dlls/win32u/input.c          | 29 +++++++++++++++++++++++++++++
 dlls/win32u/win32u_private.h |  1 +
 dlls/win32u/winstation.c     |  1 +
 3 files changed, 31 insertions(+)

diff --git a/dlls/win32u/input.c b/dlls/win32u/input.c
index 5ba7d151f57..8ab33619dd1 100644
--- a/dlls/win32u/input.c
+++ b/dlls/win32u/input.c
@@ -30,6 +30,7 @@
 #pragma makedep unix
 #endif

+#include <pthread.h>
 #include "ntstatus.h"
 #define WIN32_NO_STATUS
 #include "win32u_private.h"
@@ -39,6 +40,7 @@

WINE_DEFAULT_DEBUG_CHANNEL(win);
 WINE_DECLARE_DEBUG_CHANNEL(keyboard);
+WINE_DECLARE_DEBUG_CHANNEL(cursor);

static const WCHAR keyboard_layouts_keyW[] =
 {
@@ -2149,3 +2151,30 @@ void toggle_caret( HWND hwnd )

if (ret && !hidden) display_caret( hwnd, &r );
 }
+
+static void sync_cursor_pos(void)
+{
+    POINT pt = { 0 };
+    if (user_driver->pGetCursorPos( &pt ))
+    {
+        TRACE_(cursor)( "syncing initial cursor position at (%d, %d)\n", pt.x, pt.y );
+        NtUserSetCursorPos( pt.x, pt.y );
+    }
+    else
+    {
+        WARN_(cursor)( "initial GetCursorPos failed; cursor may be out of sync with the server\n" );
+    }
+}
+
+/***********************************************************************
+ *           init_server_cursor_pos
+ *
+ * Update the server's cursor location with the actual value from the
+ * user driver. Until the user moves the mouse, the server's location
+ * is likely incorrect.
+ */
+void init_server_cursor_pos(void)
+{
+    static pthread_once_t init_once = PTHREAD_ONCE_INIT;
+    pthread_once( &init_once, sync_cursor_pos );
+}
diff --git a/dlls/win32u/win32u_private.h b/dlls/win32u/win32u_private.h
index 4be068b968d..5800804f6cc 100644
--- a/dlls/win32u/win32u_private.h
+++ b/dlls/win32u/win32u_private.h
@@ -272,6 +272,7 @@ extern HWND get_capture(void) DECLSPEC_HIDDEN;
 extern BOOL get_cursor_pos( POINT *pt ) DECLSPEC_HIDDEN;
 extern HWND get_focus(void) DECLSPEC_HIDDEN;
 extern DWORD get_input_state(void) DECLSPEC_HIDDEN;
+extern void init_server_cursor_pos(void) DECLSPEC_HIDDEN;
 extern BOOL WINAPI release_capture(void) DECLSPEC_HIDDEN;
 extern BOOL set_capture_window( HWND hwnd, UINT gui_flags, HWND *prev_ret ) DECLSPEC_HIDDEN;
 extern BOOL set_caret_blink_time( unsigned int time ) DECLSPEC_HIDDEN;
diff --git a/dlls/win32u/winstation.c b/dlls/win32u/winstation.c
index e606047a79c..33a3b7f65c8 100644
--- a/dlls/win32u/winstation.c
+++ b/dlls/win32u/winstation.c
@@ -501,6 +501,7 @@ HWND get_desktop_window(void)
         ERR_(win)( "failed to create desktop window\n" );

register_builtin_classes();
+    init_server_cursor_pos();
     return UlongToHandle( thread_info->top_window );
 }