Zhiyi Zhang : comctl32/edit: Don't use WM_TIMER to update caret position.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 753ddd3a02a711cab54b5b2f62bf36eb35742bc2
URL:    https://gitlab.winehq.org/wine/wine/-/commit/753ddd3a02a711cab54b5b2f62bf36e...

Author: Zhiyi Zhang 
Date:   Tue Dec 13 16:18:43 2022 +0800

comctl32/edit: Don't use WM_TIMER to update caret position.

An application subclasses edit control and crashes on unexpected WM_TIMER messages. A timer was
added a long time ago and it was for auto scrolling the view when the cursor is outside of the
client area. However, with a EDIT_EM_ScrollCaret() call in EDIT_WM_MouseMove(), the view can be
scrolled to the correct position automatically. So the timer is not necessary at all. This is tested
manually with a long text in the edit control with notepad on XP, Win7 and Win10. Before this patch,
the caret will move backwards every 100ms when the clicking the left mouse button on the bottom of
the text and then dragging the cursor upwards and outside of the client area. After this, the
behavior is the same as native.

---

dlls/comctl32/edit.c | 40 +---------------------------------------
 1 file changed, 1 insertion(+), 39 deletions(-)

diff --git a/dlls/comctl32/edit.c b/dlls/comctl32/edit.c
index 24ef8a43c17..4b950412617 100644
--- a/dlls/comctl32/edit.c
+++ b/dlls/comctl32/edit.c
@@ -113,8 +113,6 @@ typedef struct
    RECT format_rect;
    INT text_width;			/* width of the widest line in pixels for multi line controls
    				   and just line width for single line controls	*/
-	INT region_posx;		/* Position of cursor relative to region: */
-	INT region_posy;		/* -1: to left, 0: within, 1: to right */
    EDITWORDBREAKPROCW word_break_proc;
    INT line_count;			/* number of lines */
    INT y_offset;			/* scroll offset in number of lines */
@@ -3438,8 +3436,6 @@ static LRESULT EDIT_WM_LButtonDblClk(EDITSTATE *es)
    e = li + EDIT_CallWordBreakProc(es, li, e - li, ll, WB_RIGHT);
    EDIT_EM_SetSel(es, s, e, FALSE);
    EDIT_EM_ScrollCaret(es);
-	es->region_posx = es->region_posy = 0;
-	SetTimer(es->hwndSelf, 0, 100, NULL);
    return 0;
 }

@@ -3460,8 +3456,6 @@ static LRESULT EDIT_WM_LButtonDown(EDITSTATE *es, DWORD keys, INT x, INT y)
    e = EDIT_CharFromPos(es, x, y, &after_wrap);
    EDIT_EM_SetSel(es, (keys & MK_SHIFT) ? es->selection_start : e, e, after_wrap);
    EDIT_EM_ScrollCaret(es);
-	es->region_posx = es->region_posy = 0;
-	SetTimer(es->hwndSelf, 0, 100, NULL);

if (!(es->flags & EF_FOCUSED))
             SetFocus(es->hwndSelf);
@@ -3478,7 +3472,6 @@ static LRESULT EDIT_WM_LButtonDown(EDITSTATE *es, DWORD keys, INT x, INT y)
 static LRESULT EDIT_WM_LButtonUp(EDITSTATE *es)
 {
    if (es->bCaptureState) {
-		KillTimer(es->hwndSelf, 0);
    	if (GetCapture() == es->hwndSelf) ReleaseCapture();
    }
    es->bCaptureState = FALSE;
@@ -3507,7 +3500,6 @@ static LRESULT EDIT_WM_MouseMove(EDITSTATE *es, INT x, INT y)
 {
    INT e;
    BOOL after_wrap;
-	INT prex, prey;

/* If the mouse has been captured by process other than the edit control itself,
          * the windows edit controls will not select the strings with mouse move.
@@ -3515,17 +3507,10 @@ static LRESULT EDIT_WM_MouseMove(EDITSTATE *es, INT x, INT y)
         if (!es->bCaptureState || GetCapture() != es->hwndSelf)
    	return 0;

-	/*
-	 *	FIXME: gotta do some scrolling if outside client
-	 *		area.  Maybe reset the timer ?
-	 */
-	prex = x; prey = y;
-	EDIT_ConfinePoint(es, &x, &y);
-	es->region_posx = (prex < x) ? -1 : ((prex > x) ? 1 : 0);
-	es->region_posy = (prey < y) ? -1 : ((prey > y) ? 1 : 0);
    e = EDIT_CharFromPos(es, x, y, &after_wrap);
    EDIT_EM_SetSel(es, es->selection_start, e, after_wrap);
    EDIT_SetCaretPos(es,es->selection_end,es->flags & EF_AFTER_WRAP);
+	EDIT_EM_ScrollCaret(es);
    return 0;
 }

@@ -3924,25 +3909,6 @@ static LRESULT EDIT_WM_SysKeyDown(EDITSTATE *es, INT key, DWORD key_data)
    return DefWindowProcW(es->hwndSelf, WM_SYSKEYDOWN, key, key_data);
 }

-
-/*********************************************************************
- *
- *	WM_TIMER
- *
- */
-static void EDIT_WM_Timer(EDITSTATE *es)
-{
-	if (es->region_posx < 0) {
-		EDIT_MoveBackward(es, TRUE);
-	} else if (es->region_posx > 0) {
-		EDIT_MoveForward(es, TRUE);
-	}
-/*
- *	FIXME: gotta do some vertical scrolling here, like
- *		EDIT_EM_LineScroll(hwnd, 0, 1);
- */
-}
-
 /*********************************************************************
  *
  *	WM_HSCROLL
@@ -4915,10 +4881,6 @@ static LRESULT CALLBACK EDIT_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPAR
         result = EDIT_WM_SysKeyDown(es, (INT)wParam, (DWORD)lParam);
         break;

-    case WM_TIMER:
-        EDIT_WM_Timer(es);
-        break;
-
     case WM_VSCROLL:
         result = EDIT_WM_VScroll(es, LOWORD(wParam), (short)HIWORD(wParam));
         break;