Merge from trunk

[bpt/emacs.git] / src / w32inevt.c

/* Input event support for Emacs on the Microsoft W32 API.
   Copyright (C) 1992, 1993, 1995, 2001, 2002, 2003, 2004, 2005, 2006,
                 2007, 2008, 2009, 2010  Free Software Foundation, Inc.

This file is part of GNU Emacs.

GNU Emacs is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */

/*
   Drew Bliss                   01-Oct-93
     Adapted from ntkbd.c by Tim Fleehart
*/


#include <config.h>
#include <stdio.h>
#include <windows.h>
#include <setjmp.h>

#ifndef MOUSE_MOVED
#define MOUSE_MOVED   1
#endif

#include "lisp.h"
#include "keyboard.h"
#include "frame.h"
#include "dispextern.h"
#include "blockinput.h"
#include "termhooks.h"
#include "w32heap.h"
#include "w32term.h"

/* stdin, from ntterm */
extern HANDLE keyboard_handle;

/* Info for last mouse motion */
static COORD movement_pos;
static DWORD movement_time;

/* from keyboard.c */
extern void reinvoke_input_signal (void);

/* from w32console.c */
extern int w32_use_full_screen_buffer;

/* from w32fns.c */
extern Lisp_Object Vw32_alt_is_meta;
extern unsigned int map_keypad_keys (unsigned int, unsigned int);

/* from w32term */
extern Lisp_Object Vw32_capslock_is_shiftlock;
extern Lisp_Object Vw32_enable_caps_lock;
extern Lisp_Object Vw32_enable_num_lock;
extern Lisp_Object Vw32_recognize_altgr;
extern Lisp_Object Vw32_pass_lwindow_to_system;
extern Lisp_Object Vw32_pass_rwindow_to_system;
extern Lisp_Object Vw32_phantom_key_code;
extern Lisp_Object Vw32_lwindow_modifier;
extern Lisp_Object Vw32_rwindow_modifier;
extern Lisp_Object Vw32_apps_modifier;
extern Lisp_Object Vw32_scroll_lock_modifier;
extern unsigned int w32_key_to_modifier (int key);

/* Event queue */
#define EVENT_QUEUE_SIZE 50
static INPUT_RECORD event_queue[EVENT_QUEUE_SIZE];
static INPUT_RECORD *queue_ptr = event_queue, *queue_end = event_queue;

/* Temporarily store lead byte of DBCS input sequences.  */
static char dbcs_lead = 0;

static int
fill_queue (BOOL block)
{
  BOOL rc;
  DWORD events_waiting;

  if (queue_ptr < queue_end)
    return queue_end-queue_ptr;

  if (!block)
    {
      /* Check to see if there are some events to read before we try
	 because we can't block.  */
      if (!GetNumberOfConsoleInputEvents (keyboard_handle, &events_waiting))
	return -1;
      if (events_waiting == 0)
	return 0;
    }

  rc = ReadConsoleInput (keyboard_handle, event_queue, EVENT_QUEUE_SIZE,
			 &events_waiting);
  if (!rc)
    return -1;
  queue_ptr = event_queue;
  queue_end = event_queue + events_waiting;
  return (int) events_waiting;
}

/* In a generic, multi-frame world this should take a console handle
   and return the frame for it

   Right now, there's only one frame so return it.  */
static FRAME_PTR
get_frame (void)
{
  return SELECTED_FRAME ();
}

/* Translate console modifiers to emacs modifiers.
   German keyboard support (Kai Morgan Zeise 2/18/95).  */
int
w32_kbd_mods_to_emacs (DWORD mods, WORD key)
{
  int retval = 0;

  /* If we recognize right-alt and left-ctrl as AltGr, and it has been
     pressed, first remove those modifiers.  */
  if (!NILP (Vw32_recognize_altgr)
      && (mods & (RIGHT_ALT_PRESSED | LEFT_CTRL_PRESSED))
      == (RIGHT_ALT_PRESSED | LEFT_CTRL_PRESSED))
    mods &= ~ (RIGHT_ALT_PRESSED | LEFT_CTRL_PRESSED);

  if (mods & (RIGHT_ALT_PRESSED | LEFT_ALT_PRESSED))
    retval = ((NILP (Vw32_alt_is_meta)) ? alt_modifier : meta_modifier);

  if (mods & (RIGHT_CTRL_PRESSED | LEFT_CTRL_PRESSED))
    {
      retval |= ctrl_modifier;
      if ((mods & (RIGHT_CTRL_PRESSED | LEFT_CTRL_PRESSED))
	  == (RIGHT_CTRL_PRESSED | LEFT_CTRL_PRESSED))
	retval |= meta_modifier;
    }

  if (mods & LEFT_WIN_PRESSED)
    retval |= w32_key_to_modifier (VK_LWIN);
  if (mods & RIGHT_WIN_PRESSED)
    retval |= w32_key_to_modifier (VK_RWIN);
  if (mods & APPS_PRESSED)
    retval |= w32_key_to_modifier (VK_APPS);
  if (mods & SCROLLLOCK_ON)
    retval |= w32_key_to_modifier (VK_SCROLL);

  /* Just in case someone wanted the original behavior, make it
     optional by setting w32-capslock-is-shiftlock to t.  */
  if (NILP (Vw32_capslock_is_shiftlock)
      /* Keys that should _not_ be affected by CapsLock.  */
      && (    (key == VK_BACK)
	   || (key == VK_TAB)
	   || (key == VK_CLEAR)
	   || (key == VK_RETURN)
	   || (key == VK_ESCAPE)
	   || ((key >= VK_SPACE) && (key <= VK_HELP))
	   || ((key >= VK_NUMPAD0) && (key <= VK_F24))
	   || ((key >= VK_NUMPAD_CLEAR) && (key <= VK_NUMPAD_DELETE))
	 ))
    {
      /* Only consider shift state.  */
      if ((mods & SHIFT_PRESSED) != 0)
	retval |= shift_modifier;
    }
  else
    {
      /* Ignore CapsLock state if not enabled.  */
      if (NILP (Vw32_enable_caps_lock))
	mods &= ~CAPSLOCK_ON;
      if ((mods & (SHIFT_PRESSED | CAPSLOCK_ON)) != 0)
	retval |= shift_modifier;
    }

  return retval;
}

#if 0
/* Return nonzero if the virtual key is a dead key.  */
static int
is_dead_key (int wparam)
{
  unsigned int code = MapVirtualKey (wparam, 2);

  /* Windows 95 returns 0x8000, NT returns 0x80000000.  */
  return (code & 0x80008000) ? 1 : 0;
}
#endif

/* The return code indicates key code size. */
int
w32_kbd_patch_key (KEY_EVENT_RECORD *event)
{
  unsigned int key_code = event->wVirtualKeyCode;
  unsigned int mods = event->dwControlKeyState;
  BYTE keystate[256];
  static BYTE ansi_code[4];
  static int isdead = 0;

  if (isdead == 2)
    {
      event->uChar.AsciiChar = ansi_code[2];
      isdead = 0;
      return 1;
    }
  if (event->uChar.AsciiChar != 0)
    return 1;

  memset (keystate, 0, sizeof (keystate));
  keystate[key_code] = 0x80;
  if (mods & SHIFT_PRESSED)
    keystate[VK_SHIFT] = 0x80;
  if (mods & CAPSLOCK_ON)
    keystate[VK_CAPITAL] = 1;
  /* If we recognize right-alt and left-ctrl as AltGr, set the key
     states accordingly before invoking ToAscii.  */
  if (!NILP (Vw32_recognize_altgr)
      && (mods & LEFT_CTRL_PRESSED) && (mods & RIGHT_ALT_PRESSED))
    {
      keystate[VK_CONTROL] = 0x80;
      keystate[VK_LCONTROL] = 0x80;
      keystate[VK_MENU] = 0x80;
      keystate[VK_RMENU] = 0x80;
    }

#if 0
  /* Because of an OS bug, ToAscii corrupts the stack when called to
     convert a dead key in console mode on NT4.  Unfortunately, trying
     to check for dead keys using MapVirtualKey doesn't work either -
     these functions apparently use internal information about keyboard
     layout which doesn't get properly updated in console programs when
     changing layout (though apparently it gets partly updated,
     otherwise ToAscii wouldn't crash).  */
  if (is_dead_key (event->wVirtualKeyCode))
    return 0;
#endif

  /* On NT, call ToUnicode instead and then convert to the current
     locale's default codepage.  */
  if (os_subtype == OS_NT)
    {
      WCHAR buf[128];

      isdead = ToUnicode (event->wVirtualKeyCode, event->wVirtualScanCode,
			  keystate, buf, 128, 0);
      if (isdead > 0)
	{
	  char cp[20];
	  int cpId;

	  event->uChar.UnicodeChar = buf[isdead - 1];

	  GetLocaleInfo (GetThreadLocale (),
			 LOCALE_IDEFAULTANSICODEPAGE, cp, 20);
	  cpId = atoi (cp);
	  isdead = WideCharToMultiByte (cpId, 0, buf, isdead,
					ansi_code, 4, NULL, NULL);
	}
      else
	isdead = 0;
    }
  else
    {
      isdead = ToAscii (event->wVirtualKeyCode, event->wVirtualScanCode,
                        keystate, (LPWORD) ansi_code, 0);
    }

  if (isdead == 0)
    return 0;
  event->uChar.AsciiChar = ansi_code[0];
  return isdead;
}


extern const char *const lispy_function_keys[];

static int faked_key = 0;

/* return code -1 means that event_queue_ptr won't be incremented.
   In other word, this event makes two key codes.   (by himi)       */
static int
key_event (KEY_EVENT_RECORD *event, struct input_event *emacs_ev, int *isdead)
{
  static int mod_key_state = 0;
  int wParam;

  *isdead = 0;

  /* Skip key-up events.  */
  if (!event->bKeyDown)
    {
      switch (event->wVirtualKeyCode)
	{
	case VK_LWIN:
	  mod_key_state &= ~LEFT_WIN_PRESSED;
	  break;
	case VK_RWIN:
	  mod_key_state &= ~RIGHT_WIN_PRESSED;
	  break;
	case VK_APPS:
	  mod_key_state &= ~APPS_PRESSED;
	  break;
	}
      return 0;
    }

  /* Ignore keystrokes we fake ourself; see below.  */
  if (faked_key == event->wVirtualKeyCode)
    {
      faked_key = 0;
      return 0;
    }

  /* To make it easier to debug this code, ignore modifier keys!  */
  switch (event->wVirtualKeyCode)
    {
    case VK_LWIN:
      if (NILP (Vw32_pass_lwindow_to_system))
	{
	  /* Prevent system from acting on keyup (which opens the Start
	     menu if no other key was pressed) by simulating a press of
	     Space which we will ignore.  */
	  if ((mod_key_state & LEFT_WIN_PRESSED) == 0)
	    {
	      if (NUMBERP (Vw32_phantom_key_code))
		faked_key = XUINT (Vw32_phantom_key_code) & 255;
	      else
		faked_key = VK_SPACE;
	      keybd_event (faked_key, (BYTE) MapVirtualKey (faked_key, 0), 0, 0);
	    }
	}
      mod_key_state |= LEFT_WIN_PRESSED;
      if (!NILP (Vw32_lwindow_modifier))
	return 0;
      break;
    case VK_RWIN:
      if (NILP (Vw32_pass_rwindow_to_system))
	{
	  if ((mod_key_state & RIGHT_WIN_PRESSED) == 0)
	    {
	      if (NUMBERP (Vw32_phantom_key_code))
		faked_key = XUINT (Vw32_phantom_key_code) & 255;
	      else
		faked_key = VK_SPACE;
	      keybd_event (faked_key, (BYTE) MapVirtualKey (faked_key, 0), 0, 0);
	    }
	}
      mod_key_state |= RIGHT_WIN_PRESSED;
      if (!NILP (Vw32_rwindow_modifier))
	return 0;
      break;
    case VK_APPS:
      mod_key_state |= APPS_PRESSED;
      if (!NILP (Vw32_apps_modifier))
	return 0;
      break;
    case VK_CAPITAL:
      /* Decide whether to treat as modifier or function key.  */
      if (NILP (Vw32_enable_caps_lock))
	goto disable_lock_key;
      return 0;
    case VK_NUMLOCK:
      /* Decide whether to treat as modifier or function key.  */
      if (NILP (Vw32_enable_num_lock))
	goto disable_lock_key;
      return 0;
    case VK_SCROLL:
      /* Decide whether to treat as modifier or function key.  */
      if (NILP (Vw32_scroll_lock_modifier))
	goto disable_lock_key;
      return 0;
    disable_lock_key:
      /* Ensure the appropriate lock key state is off (and the
	 indicator light as well).  */
      wParam = event->wVirtualKeyCode;
      if (GetAsyncKeyState (wParam) & 0x8000)
	{
	  /* Fake another press of the relevant key.  Apparently, this
	     really is the only way to turn off the indicator.  */
	  faked_key = wParam;
	  keybd_event ((BYTE) wParam, (BYTE) MapVirtualKey (wParam, 0),
		       KEYEVENTF_EXTENDEDKEY | KEYEVENTF_KEYUP, 0);
	  keybd_event ((BYTE) wParam, (BYTE) MapVirtualKey (wParam, 0),
		       KEYEVENTF_EXTENDEDKEY | 0, 0);
	  keybd_event ((BYTE) wParam, (BYTE) MapVirtualKey (wParam, 0),
		       KEYEVENTF_EXTENDEDKEY | KEYEVENTF_KEYUP, 0);
	}
      break;
    case VK_MENU:
    case VK_CONTROL:
    case VK_SHIFT:
      return 0;
    case VK_CANCEL:
      /* Windows maps Ctrl-Pause (aka Ctrl-Break) into VK_CANCEL,
	 which is confusing for purposes of key binding; convert
	 VK_CANCEL events into VK_PAUSE events.  */
      event->wVirtualKeyCode = VK_PAUSE;
      break;
    case VK_PAUSE:
      /* Windows maps Ctrl-NumLock into VK_PAUSE, which is confusing
	 for purposes of key binding; convert these back into
	 VK_NUMLOCK events, at least when we want to see NumLock key
	 presses.  (Note that there is never any possibility that
	 VK_PAUSE with Ctrl really is C-Pause as per above.)  */
      if (NILP (Vw32_enable_num_lock)
	  && (event->dwControlKeyState
	      & (LEFT_CTRL_PRESSED | RIGHT_CTRL_PRESSED)) != 0)
	event->wVirtualKeyCode = VK_NUMLOCK;
      break;
    }

  /* Recognize state of Windows and Apps keys.  */
  event->dwControlKeyState |= mod_key_state;

  /* Distinguish numeric keypad keys from extended keys.  */
  event->wVirtualKeyCode =
    map_keypad_keys (event->wVirtualKeyCode,
		     (event->dwControlKeyState & ENHANCED_KEY));

  if (lispy_function_keys[event->wVirtualKeyCode] == 0)
    {
      if (!NILP (Vw32_recognize_altgr)
	  && (event->dwControlKeyState & LEFT_CTRL_PRESSED)
	  && (event->dwControlKeyState & RIGHT_ALT_PRESSED))
	{
	  /* Don't try to interpret AltGr key chords; ToAscii seems not
	     to process them correctly.  */
	}
      /* Handle key chords including any modifiers other than shift
         directly, in order to preserve as much modifier information as
         possible.  */
      else if (event->dwControlKeyState
	       & (  RIGHT_CTRL_PRESSED | LEFT_CTRL_PRESSED
		  | RIGHT_ALT_PRESSED | LEFT_ALT_PRESSED
		  | (!NILP (Vw32_lwindow_modifier) ? LEFT_WIN_PRESSED : 0)
		  | (!NILP (Vw32_rwindow_modifier) ? RIGHT_WIN_PRESSED : 0)
		  | (!NILP (Vw32_apps_modifier) ? APPS_PRESSED : 0)
		  | (!NILP (Vw32_scroll_lock_modifier) ? SCROLLLOCK_ON : 0)))
	{
	  /* Don't translate modified alphabetic keystrokes, so the user
	     doesn't need to constantly switch layout to type control or
	     meta keystrokes when the normal layout translates
	     alphabetic characters to non-ascii characters.  */
	  if ('A' <= event->wVirtualKeyCode && event->wVirtualKeyCode <= 'Z')
	    {
	      event->uChar.AsciiChar = event->wVirtualKeyCode;
	      if ((event->dwControlKeyState & SHIFT_PRESSED) == 0)
		event->uChar.AsciiChar += ('a' - 'A');
	    }
	  /* Try to handle unrecognized keystrokes by determining the
             base character (ie. translating the base key plus shift
             modifier).  */
	  else if (event->uChar.AsciiChar == 0)
	    w32_kbd_patch_key (event);
	}

      if (event->uChar.AsciiChar == 0)
	{
	  emacs_ev->kind = NO_EVENT;
	  return 0;
	}
      else if (event->uChar.AsciiChar > 0)
	{
	  emacs_ev->kind = ASCII_KEYSTROKE_EVENT;
	  emacs_ev->code = event->uChar.AsciiChar;
	}
      else if (event->uChar.UnicodeChar > 0)
	{
	  emacs_ev->kind = MULTIBYTE_CHAR_KEYSTROKE_EVENT;
	  emacs_ev->code = event->uChar.UnicodeChar;
	}
      else
	{
	  /* Fallback for non-Unicode versions of Windows.  */
	  wchar_t code;
	  char dbcs[2];
          char cp[20];
          int cpId;

	  /* Get the codepage to interpret this key with.  */
          GetLocaleInfo (GetThreadLocale (),
			 LOCALE_IDEFAULTANSICODEPAGE, cp, 20);
          cpId = atoi (cp);

	  dbcs[0] = dbcs_lead;
	  dbcs[1] = event->uChar.AsciiChar;
	  if (dbcs_lead)
	    {
	      dbcs_lead = 0;
	      if (!MultiByteToWideChar (cpId, 0, dbcs, 2, &code, 1))
		{
		  /* Garbage  */
		  DebPrint (("Invalid DBCS sequence: %d %d\n",
			     dbcs[0], dbcs[1]));
		  emacs_ev->kind = NO_EVENT;
		}
	    }
	  else if (IsDBCSLeadByteEx (cpId, dbcs[1]))
	    {
	      dbcs_lead = dbcs[1];
	      emacs_ev->kind = NO_EVENT;
	    }
	  else
	    {
	      if (!MultiByteToWideChar (cpId, 0, &dbcs[1], 1, &code, 1))
		{
		  /* Garbage  */
		  DebPrint (("Invalid character: %d\n", dbcs[1]));
		  emacs_ev->kind = NO_EVENT;
		}
	    }
	  emacs_ev->kind = MULTIBYTE_CHAR_KEYSTROKE_EVENT;
	  emacs_ev->code = code;
	}
    }
  else
    {
      emacs_ev->kind = NON_ASCII_KEYSTROKE_EVENT;
      emacs_ev->code = event->wVirtualKeyCode;
    }

  XSETFRAME (emacs_ev->frame_or_window, get_frame ());
  emacs_ev->modifiers = w32_kbd_mods_to_emacs (event->dwControlKeyState,
					       event->wVirtualKeyCode);
  emacs_ev->timestamp = GetTickCount ();
  return 1;
}

int
w32_console_toggle_lock_key (int vk_code, Lisp_Object new_state)
{
  int cur_state = (GetKeyState (vk_code) & 1);

  if (NILP (new_state)
      || (NUMBERP (new_state)
	  && ((XUINT (new_state)) & 1) != cur_state))
    {
      faked_key = vk_code;

      keybd_event ((BYTE) vk_code,
		   (BYTE) MapVirtualKey (vk_code, 0),
		   KEYEVENTF_EXTENDEDKEY | KEYEVENTF_KEYUP, 0);
      keybd_event ((BYTE) vk_code,
		   (BYTE) MapVirtualKey (vk_code, 0),
		   KEYEVENTF_EXTENDEDKEY | 0, 0);
      keybd_event ((BYTE) vk_code,
		   (BYTE) MapVirtualKey (vk_code, 0),
		   KEYEVENTF_EXTENDEDKEY | KEYEVENTF_KEYUP, 0);
      cur_state = !cur_state;
    }

  return cur_state;
}

/* Mouse position hook.  */
void
w32_console_mouse_position (FRAME_PTR *f,
			    int insist,
			    Lisp_Object *bar_window,
			    enum scroll_bar_part *part,
			    Lisp_Object *x,
			    Lisp_Object *y,
			    unsigned long *time)
{
  BLOCK_INPUT;

  insist = insist;

  *f = get_frame ();
  *bar_window = Qnil;
  *part = 0;
  SELECTED_FRAME ()->mouse_moved = 0;

  XSETINT (*x, movement_pos.X);
  XSETINT (*y, movement_pos.Y);
  *time = movement_time;

  UNBLOCK_INPUT;
}

/* Remember mouse motion and notify emacs.  */
static void
mouse_moved_to (int x, int y)
{
  /* If we're in the same place, ignore it */
  if (x != movement_pos.X || y != movement_pos.Y)
    {
      SELECTED_FRAME ()->mouse_moved = 1;
      movement_pos.X = x;
      movement_pos.Y = y;
      movement_time = GetTickCount ();
    }
}

/* Consoles return button bits in a strange order:
     least significant - Leftmost button
     next - Rightmost button
     next - Leftmost+1
     next - Leftmost+2...

   Assume emacs likes three button mice, so
     Left == 0
     Middle == 1
     Right == 2
   Others increase from there.  */

#define NUM_TRANSLATED_MOUSE_BUTTONS 3
static int emacs_button_translation[NUM_TRANSLATED_MOUSE_BUTTONS] =
{
  0, 2, 1
};

static int
do_mouse_event (MOUSE_EVENT_RECORD *event,
		struct input_event *emacs_ev)
{
  static DWORD button_state = 0;
  DWORD but_change, mask;
  int i;

  if (event->dwEventFlags == MOUSE_MOVED)
    {
      /* For movement events we just note that the mouse has moved
	 so that emacs will generate drag events.  */
      mouse_moved_to (event->dwMousePosition.X, event->dwMousePosition.Y);
      return 0;
    }

  /* It looks like the console code sends us a mouse event with
     dwButtonState == 0 when a window is activated.  Ignore this case.  */
  if (event->dwButtonState == button_state)
    return 0;

  emacs_ev->kind = MOUSE_CLICK_EVENT;

  /* Find out what button has changed state since the last button event.  */
  but_change = button_state ^ event->dwButtonState;
  mask = 1;
  for (i = 0; mask; i++, mask <<= 1)
    if (but_change & mask)
      {
        if (i < NUM_TRANSLATED_MOUSE_BUTTONS)
          emacs_ev->code = emacs_button_translation[i];
        else
          emacs_ev->code = i;
	break;
      }

  button_state = event->dwButtonState;
  emacs_ev->timestamp = GetTickCount ();
  emacs_ev->modifiers = w32_kbd_mods_to_emacs (event->dwControlKeyState, 0) |
    ((event->dwButtonState & mask) ? down_modifier : up_modifier);

  XSETFASTINT (emacs_ev->x, event->dwMousePosition.X);
  XSETFASTINT (emacs_ev->y, event->dwMousePosition.Y);
/* for Mule 2.2 (Based on Emacs 19.28 */
#ifdef MULE
  XSET (emacs_ev->frame_or_window, Lisp_Frame, get_frame ());
#else
  XSETFRAME (emacs_ev->frame_or_window, get_frame ());
#endif

  return 1;
}

static void
resize_event (WINDOW_BUFFER_SIZE_RECORD *event)
{
  FRAME_PTR f = get_frame ();

  change_frame_size (f, event->dwSize.Y, event->dwSize.X, 0, 1, 0);
  SET_FRAME_GARBAGED (f);
}

static void
maybe_generate_resize_event (void)
{
  CONSOLE_SCREEN_BUFFER_INFO info;
  FRAME_PTR f = get_frame ();

  GetConsoleScreenBufferInfo (GetStdHandle (STD_OUTPUT_HANDLE), &info);

  /* It is okay to call this unconditionally, since it will do nothing
     if the size hasn't actually changed.  */
  change_frame_size (f,
		     1 + info.srWindow.Bottom - info.srWindow.Top,
		     1 + info.srWindow.Right - info.srWindow.Left,
		     0, 0, 0);
}

int
w32_console_read_socket (struct terminal *terminal,
                         int expected,
                         struct input_event *hold_quit)
{
  BOOL no_events = TRUE;
  int nev, ret = 0, add;
  int isdead;

  if (interrupt_input_blocked)
    {
      interrupt_input_pending = 1;
      return -1;
    }

  interrupt_input_pending = 0;
  BLOCK_INPUT;

  for (;;)
    {
      nev = fill_queue (0);
      if (nev <= 0)
        {
	  /* If nev == -1, there was some kind of error
	     If nev == 0 then waitp must be zero and no events were available
	     so return.  */
	  UNBLOCK_INPUT;
	  return nev;
        }

      while (nev > 0)
        {
	  struct input_event inev;

	  EVENT_INIT (inev);
	  inev.kind = NO_EVENT;
	  inev.arg = Qnil;

	  switch (queue_ptr->EventType)
            {
            case KEY_EVENT:
	      add = key_event (&queue_ptr->Event.KeyEvent, &inev, &isdead);
	      if (add == -1) /* 95.7.25 by himi */
		{
		  queue_ptr--;
		  add = 1;
		}
	      if (add)
		kbd_buffer_store_event_hold (&inev, hold_quit);
	      break;

            case MOUSE_EVENT:
	      add = do_mouse_event (&queue_ptr->Event.MouseEvent, &inev);
	      if (add)
		kbd_buffer_store_event_hold (&inev, hold_quit);
	      break;

            case WINDOW_BUFFER_SIZE_EVENT:
	      if (w32_use_full_screen_buffer)
		resize_event (&queue_ptr->Event.WindowBufferSizeEvent);
	      break;

            case MENU_EVENT:
            case FOCUS_EVENT:
	      /* Internal event types, ignored. */
	      break;
            }

	  queue_ptr++;
	  nev--;
        }

      if (ret > 0 || expected == 0)
	break;
    }

  /* We don't get told about changes in the window size (only the buffer
     size, which we no longer care about), so we have to check it
     periodically.  */
  if (!w32_use_full_screen_buffer)
    maybe_generate_resize_event ();

  UNBLOCK_INPUT;
  return ret;
}