/* blockinput.h - interface to blocking complicated interrupt-driven input.
- Copyright (C) 1989, 1993, 2001-2012 Free Software Foundation, Inc.
+ Copyright (C) 1989, 1993, 2001-2016 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.
+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
#ifndef EMACS_BLOCKINPUT_H
#define EMACS_BLOCKINPUT_H
-#include "atimer.h"
+INLINE_HEADER_BEGIN
-/* When Emacs is using signal-driven input, the processing of those
- input signals can get pretty hairy. For example, when Emacs is
- running under X windows, handling an input signal can entail
- retrieving events from the X event queue, or making other X calls.
-
- If an input signal occurs while Emacs is in the midst of some
- non-reentrant code, and the signal processing invokes that same
- code, we lose. For example, malloc and the Xlib functions aren't
- usually re-entrant, and both are used by the X input signal handler
- - if we try to process an input signal in the midst of executing
- any of these functions, we'll lose.
+/* Emacs should avoid doing anything hairy in a signal handler, because
+ so many system functions are non-reentrant. For example, malloc
+ and the Xlib functions aren't usually re-entrant, so if they were
+ used by the SIGIO handler, we'd lose.
To avoid this, we make the following requirements:
- * Everyone must evaluate BLOCK_INPUT before entering these functions,
- and then call UNBLOCK_INPUT after performing them. Calls
- BLOCK_INPUT and UNBLOCK_INPUT may be nested.
+ * Everyone must evaluate BLOCK_INPUT before performing actions that
+ might conflict with a signal handler, and then call UNBLOCK_INPUT
+ after performing them. Calls BLOCK_INPUT and UNBLOCK_INPUT may be
+ nested.
* Any complicated interrupt handling code should test
- interrupt_input_blocked, and put off its work until later.
+ INPUT_BLOCKED_P, and put off its work until later.
* If the interrupt handling code wishes, it may set
- interrupt_input_pending to a non-zero value. If that flag is set
- when input becomes unblocked, UNBLOCK_INPUT will send a new SIGIO. */
+ pending_signals to a non-zero value. If that flag is set
+ when input becomes unblocked, UNBLOCK_INPUT will then read
+ input and process timers.
+
+ Historically, Emacs signal handlers did much more than they do now,
+ and this caused many BLOCK_INPUT calls to be sprinkled around the code.
+ FIXME: Remove calls that aren't needed now. */
extern volatile int interrupt_input_blocked;
-/* Nonzero means an input interrupt has arrived
- during the current critical section. */
-extern int interrupt_input_pending;
+/* Begin critical section. */
+INLINE void
+block_input (void)
+{
+ interrupt_input_blocked++;
+}
-/* Non-zero means asynchronous timers should be run when input is
- unblocked. */
+extern void unblock_input (void);
+extern void totally_unblock_input (void);
+extern void unblock_input_to (int);
-extern int pending_atimers;
+/* In critical section? */
+INLINE bool
+input_blocked_p (void)
+{
+ return interrupt_input_blocked > 0;
+}
-/* Begin critical section. */
-#define BLOCK_INPUT (interrupt_input_blocked++)
-
-/* End critical section.
-
- If doing signal-driven input, and a signal came in when input was
- blocked, reinvoke the signal handler now to deal with it.
-
- Always test interrupt_input_pending; that's not too expensive, and
- it'll never get set if we don't need to resignal. This is simpler
- than dealing here with every configuration option that might affect
- whether interrupt_input_pending can be nonzero. */
-
-#define UNBLOCK_INPUT \
- do \
- { \
- --interrupt_input_blocked; \
- if (interrupt_input_blocked == 0) \
- { \
- if (interrupt_input_pending) \
- reinvoke_input_signal (); \
- if (pending_atimers) \
- do_pending_atimers (); \
- } \
- else if (interrupt_input_blocked < 0) \
- emacs_abort (); \
- } \
- while (0)
-
-/* Undo any number of BLOCK_INPUT calls,
- and also reinvoke any pending signal. */
-
-#define TOTALLY_UNBLOCK_INPUT \
- do if (interrupt_input_blocked != 0) \
- { \
- interrupt_input_blocked = 1; \
- UNBLOCK_INPUT; \
- } \
- while (0)
-
-/* Undo any number of BLOCK_INPUT calls down to level LEVEL,
- and also (if the level is now 0) reinvoke any pending signal. */
-
-#define UNBLOCK_INPUT_TO(LEVEL) \
- do \
- { \
- interrupt_input_blocked = (LEVEL) + 1; \
- UNBLOCK_INPUT; \
- } \
- while (0)
-
-#define UNBLOCK_INPUT_RESIGNAL UNBLOCK_INPUT
-
-/* In critical section ? */
-#define INPUT_BLOCKED_P (interrupt_input_blocked > 0)
-
-/* Defined in keyboard.c */
-extern void reinvoke_input_signal (void);
+INLINE_HEADER_END
#endif /* EMACS_BLOCKINPUT_H */