From 5ad57373701686876c604f3bd58fbb2e449d5d81 Mon Sep 17 00:00:00 2001
From: Joachim Henze <joachim.henze@reactos.org>
Date: Sun, 12 Feb 2023 00:35:27 +0100
Subject: [PATCH] [NTUSER] Delete temporary workarounds in
 co_IntSetScrollInfo() (#4985)

fixes JIRA issue: CORE-18050

improves the code by removing ancient hacks (the static variables)

reduces testbot failures
VBox: https://reactos.org/testman/compare.php?ids=85831,85832 LGTM (-2 failures in user32:scroll for both bots)
KVM: https://reactos.org/testman/compare.php?ids=85829,85833 LGTM (-2 failures in user32:scroll for both bots)

co-authored by Doug-Lyons
---
 win32ss/user/ntuser/scrollbar.c | 60 ++++-----------------------------
 1 file changed, 6 insertions(+), 54 deletions(-)

diff --git a/win32ss/user/ntuser/scrollbar.c b/win32ss/user/ntuser/scrollbar.c
index 3763ac5c494..e52b70a21da 100644
--- a/win32ss/user/ntuser/scrollbar.c
+++ b/win32ss/user/ntuser/scrollbar.c
@@ -488,20 +488,15 @@ co_IntSetScrollInfo(PWND Window, INT nBar, LPCSCROLLINFO lpsi, BOOL bRedraw)
    UINT new_flags;
    INT action = 0;
    PSBDATA pSBData;
-   DWORD OldPos = 0, CurrentPos = 0;
+   DWORD OldPos = 0;
    BOOL bChangeParams = FALSE; /* Don't show/hide scrollbar if params don't change */
    UINT MaxPage;
    int MaxPos;
-   /* [0] = SB_HORZ, [1] = SB_VERT, [2] = SB_CTL */
-   static PWND PrevHwnd[3] = { 0 };
-   static DWORD PrevPos[3] = { 0 };
-   static DWORD PrevMax[3] = { 0 };
-   static INT PrevAction[3] = { 0 };
    BOOL bVisible;
 
    ASSERT_REFS_CO(Window);
 
-   if(!SBID_IS_VALID(nBar)) /* Assures nBar is 0, 1, or 2 */
+   if(!SBID_IS_VALID(nBar))
    {
       EngSetLastError(ERROR_INVALID_PARAMETER);
       ERR("Trying to set scrollinfo for unknown scrollbar type %d\n", nBar);
@@ -548,9 +543,9 @@ co_IntSetScrollInfo(PWND Window, INT nBar, LPCSCROLLINFO lpsi, BOOL bRedraw)
    /* Set the scroll pos */
    if (lpsi->fMask & SIF_POS)
    {
+      OldPos = Info->nPos;
       if (Info->nPos != lpsi->nPos)
       {
-         OldPos = Info->nPos;
          Info->nPos = lpsi->nPos;
          pSBData->pos = lpsi->nPos;
       }
@@ -645,16 +640,6 @@ co_IntSetScrollInfo(PWND Window, INT nBar, LPCSCROLLINFO lpsi, BOOL bRedraw)
    }
 
 //done:
-   if ((Window != PrevHwnd[nBar]) || (action != PrevAction[nBar]))
-   {
-      if ((action == SA_SSI_SHOW) && (PrevAction[nBar] == SA_SSI_HIDE))
-      {
-         co_UserShowScrollBar(Window, nBar, TRUE, TRUE);
-      }
-   }
-   if ((action != PrevAction[nBar]) && action != 0)
-      PrevAction[nBar] = action;
-
    if ( action & SA_SSI_HIDE )
    {
       co_UserShowScrollBar(Window, nBar, FALSE, FALSE);
@@ -685,7 +670,6 @@ co_IntSetScrollInfo(PWND Window, INT nBar, LPCSCROLLINFO lpsi, BOOL bRedraw)
       {
          if (!(Info->fMask & SIF_THEMED)) /* Not Using Themes */
          {
-            TRACE("Not using themes.\n");
             if (action & SA_SSI_REPAINT_ARROWS)
             {
                // Redraw the entire bar.
@@ -702,50 +686,18 @@ co_IntSetScrollInfo(PWND Window, INT nBar, LPCSCROLLINFO lpsi, BOOL bRedraw)
                IntRefeshScrollInterior(Window, nBar, psbi);
             }
          }
-         else  /* Using Themes */
+         else /* Using Themes */
          {
             RECTL UpdateRect = psbi->rcScrollBar;
-            TRACE("Using themes.\n");
             UpdateRect.left -= Window->rcClient.left - Window->rcWindow.left;
             UpdateRect.right -= Window->rcClient.left - Window->rcWindow.left;
             UpdateRect.top -= Window->rcClient.top - Window->rcWindow.top;
             UpdateRect.bottom -= Window->rcClient.top - Window->rcWindow.top;
-            /* Just paint the interior and not the arrows. */
-            if (!(action & SA_SSI_REPAINT_ARROWS))
-            {
-               if (nBar == SB_HORZ)
-               {
-                  UpdateRect.left += psbi->dxyLineButton;
-                  UpdateRect.right -= psbi->dxyLineButton;
-               }
-               if (nBar == SB_VERT)
-               {
-                  UpdateRect.top += psbi->dxyLineButton;
-                  UpdateRect.bottom -= psbi->dxyLineButton;
-               }
-            }
-            CurrentPos = lpsi->fMask & SIF_PREVIOUSPOS ? OldPos : pSBData->pos;
-            /* Check for changes to Window or CurrentPos or lpsi->nMax */
-            if ((Window != PrevHwnd[nBar]) || (CurrentPos != PrevPos[nBar]) ||
-               (lpsi->nMax != PrevMax[nBar]))
-            {
+            if (bChangeParams || (OldPos != pSBData->pos))
                 co_UserRedrawWindow(Window, &UpdateRect, 0, RDW_INVALIDATE | RDW_FRAME);
-                PrevHwnd[nBar] = Window;
-                PrevPos[nBar] = CurrentPos;
-                PrevMax[nBar] = lpsi->nMax;
-            }
          }
-      } // FIXME: Arrows
-/*      else if( action & SA_SSI_REPAINT_ARROWS )
-      {
-         RECTL UpdateRect = psbi->rcScrollBar;
-         UpdateRect.left -= Window->rcClient.left - Window->rcWindow.left;
-         UpdateRect.right -= Window->rcClient.left - Window->rcWindow.left;
-         UpdateRect.top -= Window->rcClient.top - Window->rcWindow.top;
-         UpdateRect.bottom -= Window->rcClient.top - Window->rcWindow.top;
-         co_UserRedrawWindow(Window, &UpdateRect, 0, RDW_INVALIDATE | RDW_FRAME);
       }
-*/   }
+   }
 
    if (bChangeParams && (nBar == SB_HORZ || nBar == SB_VERT) && (lpsi->fMask & SIF_DISABLENOSCROLL))
    {