PDCursesMod/WinGUI now uses the polling fallback again with a temporary workaround

* The keyboard hook required polling as well and was actually much less performant
  than the generic getch() polling fallback.
  Furthemore it did at least not work on Wine.
* We instead now release the WinGUI-internal mutex and yield the thread giving
  it some time to process new key presses.
* This workaround is temporary and will probably be part of the the next PDCursesMod-release
  (v4.3.4). We still want to support the latest MSYS/MinGW version though which is
  currently at v4.3.2.
  The fix will also currently only work when statically linking in libpdcurses_wingui.a.
  This is what we do for nightly builds.
  See also https://github.com/Bill-Gray/PDCursesMod/issues/197
* Once the fix is released upstream and into MSYS, we should probably bump our
  minimal required PDCursesMod version.
  The color-table workaround (cf9ffc0cec0d2e55930238d1752209bca659c96d) can then also be removed.
* We should also consider dropping official support for the classic PDCurses and support
  only PDCursesMod - this will allow us to simplify interfaces-curses/interface.c a bit.
  Support for classic PDCurses is probably broken by now anyway and trying to support it
  is just too much.

2 files changed, 21 insertions, 76 deletions

diff --git a/configure.ac b/configure.ac
index 3f50576..0ad8594 100644
--- a/configure.ac
+++ b/configure.ac
@@ -298,6 +298,13 @@ case $INTERFACE in
 			AC_DEFINE(PDC_FORCE_UTF8, 1, [PDCursesMod forces use of UTF8])
 		])
 
+		# This is actually a symbol (CRITICAL_SECTION) used by PDCursesMod/WinGUI
+		# for synchronization. We use this as a workaround to gain responsiveness
+		# while polling for keypresses.
+		# NOTE: Can currently only be detected when linking against the static
+		# libpdcurses_wingui.a.
+		AC_CHECK_FUNCS([PDC_cs])
+
 		# This is detectable at runtime on PDCursesMod using PDC_get_version().
 		# "Classic" PDCurses however does not allow runtime or compile-time checks for
 		# discerning eg. WinCon from SDL.
diff --git a/src/interface-curses/interface.c b/src/interface-curses/interface.c
index 186525f..5503d11 100644
--- a/src/interface-curses/interface.c
+++ b/src/interface-curses/interface.c
@@ -128,55 +128,6 @@ teco_console_ctrl_handler(DWORD type)
 
 #endif
 
-#if defined(PDCURSES_GUI) && defined(G_OS_WIN32)
-
-/**
- * Hooks into the key processing to catch CTRL+C.
- *
- * FIXME: This might be used as the default way to catch CTRL+C on
- * all Windows ports, even including Gtk+.
- */
-static LRESULT CALLBACK
-teco_keyboard_hook(int nCode, WPARAM wParam, LPARAM lParam)
-{
-	PKBDLLHOOKSTRUCT p = (PKBDLLHOOKSTRUCT)lParam;
-	static gboolean ctrl_pressed = FALSE;
-
-	if (nCode == HC_ACTION) {
-		switch (wParam) {
-		case WM_KEYDOWN:
-			switch (p->vkCode) {
-			case VK_LCONTROL:
-			case VK_RCONTROL:
-			case VK_CONTROL:
-				ctrl_pressed = TRUE;
-				break;
-			case 0x43: /* C */
-				if (ctrl_pressed) {
-					teco_sigint_occurred = TRUE;
-					return 1;
-				}
-				break;
-			}
-			break;
-
-		case WM_KEYUP:
-			switch (p->vkCode) {
-			case VK_LCONTROL:
-			case VK_RCONTROL:
-			case VK_CONTROL:
-				ctrl_pressed = FALSE;
-				break;
-			}
-			break;
-		}
-	}
-
-	return CallNextHookEx(NULL, nCode, wParam, lParam);
-}
-
-#endif
-
 static gint teco_xterm_version(void) G_GNUC_UNUSED;
 
 #define UNNAMED_FILE "(Unnamed)"
@@ -415,7 +366,7 @@ teco_interface_init(void)
 {
 	for (guint i = 0; i < G_N_ELEMENTS(teco_interface.color_table); i++)
 		teco_interface.color_table[i] = -1;
-#ifdef PDCURSES_GUI
+#if defined(__PDCURSESMOD__) && defined(PDCURSES_GUI)
 	/* NOTE: Fixed and no longer necessary in PDCursesMod v4.3.3. */
 	teco_interface.color_table[8] = 0x808080;
 #endif
@@ -1510,21 +1461,7 @@ teco_interface_is_interrupted(void)
 	return teco_sigint_occurred != FALSE;
 }
 
-#elif defined(PDCURSES_GUI) && defined(G_OS_WIN32)
-
-gboolean
-teco_interface_is_interrupted(void)
-{
-	/*
-	 * NOTE: The teco_keyboard_hook() is only called from event loops.
-	 */
-	MSG msg;
-	PeekMessageA(&msg, NULL, 0, 0, PM_NOREMOVE);
-
-	return teco_sigint_occurred != FALSE;
-}
-
-#else /* !CURSES_TTY && !PDCURSES_WINCON && !NCURSES_WIN32 && (!PDCURSES_GUI || !G_OS_WIN32) */
+#else /* !CURSES_TTY && !PDCURSES_WINCON && !NCURSES_WIN32 */
 
 /*
  * This function is called repeatedly, so we can poll the keyboard input queue,
@@ -1539,6 +1476,18 @@ teco_interface_is_interrupted(void)
 		gint key;
 
 		/*
+		 * This is a workaround for PDCursesMod/WinGUI that will
+		 * likely be fixed in versions newer than v4.3.3.
+		 * See also https://github.com/Bill-Gray/PDCursesMod/issues/197
+		 */
+#if defined(HAVE_PDC_CS) && PDC_BUILD <= 4303
+		extern CRITICAL_SECTION PDC_cs;
+		LeaveCriticalSection(&PDC_cs);
+		SwitchToThread();
+		EnterCriticalSection(&PDC_cs);
+#endif
+
+		/*
 		 * NOTE: getch() is configured to be nonblocking.
 		 */
 		while ((key = wgetch(teco_interface.cmdline_window)) != ERR) {
@@ -1557,13 +1506,6 @@ teco_interface_is_interrupted(void)
 static gint
 teco_interface_blocking_getch(void)
 {
-#if defined(PDCURSES_GUI) && defined(G_OS_WIN32)
-	static HHOOK keyboard_hook = NULL;
-
-	if (G_LIKELY(keyboard_hook != NULL))
-		UnhookWindowsHookEx(keyboard_hook);
-#endif
-
 	/*
 	 * Setting function key processing is important
 	 * on Unix Curses, as ESCAPE is handled as the beginning
@@ -1598,10 +1540,6 @@ teco_interface_blocking_getch(void)
 	cbreak();
 #endif
 
-#if defined(PDCURSES_GUI) && defined(G_OS_WIN32)
-	keyboard_hook = SetWindowsHookEx(WH_KEYBOARD_LL, teco_keyboard_hook, NULL, 0);
-#endif
-
 	return key;
 }