[PATCH v2 4/8] shell32/autocomplete: Don't autocomplete at all on most control characters

[Gabriel Ivăncescu]

Most control characters sent via some CTRL+key combination should not
autocomplete at all. ^C is one example, where just copying some text should
not show the auto-suggestion box (if not visible). ^V is another example,
where it is already handled in WM_PASTE, so it has to be a no-op here,
else auto-append from WM_PASTE would complete the text and then the ^V
autocompletion would remove every other suggestion in the listbox (which
is not desirable nor does it match Windows).

Signed-off-by: Gabriel Ivăncescu <gabrielopcode at gmail.com>
---

Rather than check for ^C and ^V as special cases, I decided to ignore most
control characters, with notable exceptions like Backspace and Tab characters
(since they actually do something) and the newline stuff in that range.

Unfortunately, I can't seem to find a better way. I realize this looks like
a hack, but it doesn't seem like there's another way to me. ^C is obvious:
there's nothing we can do in WM_COPY (even if we handled it, somehow)
because the ^C will still be there waiting to be processed after it.

^V is less obvious. Right now, if you paste something via CTRL+V (instead of
right-click -> Paste) and it gets auto-appended, the resulting suggestions
will be removed because the autocomplete will happen *twice*. The first time
in WM_PASTE (properly) and then in ^V when it will "see" the entire text
because of the auto-append from WM_PASTE, and thus removes all the other
suggestions. This should not happen. Pasting via right-click obviously does
not have this problem, but it is the reason we have to do it in WM_PASTE
as well, anyway. This makes ^V have the same behavior as Right-click + Paste.

 dlls/shell32/autocomplete.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/dlls/shell32/autocomplete.c b/dlls/shell32/autocomplete.c
index ef835b9..92afbe2 100644
--- a/dlls/shell32/autocomplete.c
+++ b/dlls/shell32/autocomplete.c
@@ -359,6 +359,10 @@ static LRESULT APIENTRY ACEditSubclassProc(HWND hwnd, UINT uMsg, WPARAM wParam,
             return ACEditSubclassProc_KeyDown(This, hwnd, uMsg, wParam, lParam);
         case WM_CHAR:
         case WM_UNICHAR:
+            /* Don't autocomplete at all on most control characters */
+            if (wParam < '\b' || (wParam > '\r' && wParam < ' '))
+                break;
+
             ret = CallWindowProcW(This->wpOrigEditProc, hwnd, uMsg, wParam, lParam);
             autocomplete_text(This, hwnd, (This->options & ACO_AUTOAPPEND) && wParam >= ' '
                                           ? autoappend_flag_yes : autoappend_flag_no);
-- 
1.9.1