diff options
Diffstat (limited to 'src/blockinput.h')
| -rw-r--r-- | src/blockinput.h | 118 |
1 files changed, 36 insertions, 82 deletions
diff --git a/src/blockinput.h b/src/blockinput.h index 7501bfc91a0..70822e29be7 100644 --- a/src/blockinput.h +++ b/src/blockinput.h @@ -19,103 +19,57 @@ along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>. */ #ifndef EMACS_BLOCKINPUT_H #define EMACS_BLOCKINPUT_H -#include "atimer.h" +INLINE_HEADER_BEGIN +#ifndef BLOCKINPUT_INLINE +# define BLOCKINPUT_INLINE INLINE +#endif -/* 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. */ - -extern volatile int interrupt_input_blocked; - -/* Nonzero means an input interrupt has arrived - during the current critical section. */ -extern int interrupt_input_pending; + 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. */ -/* Non-zero means asynchronous timers should be run when input is - unblocked. */ +extern volatile int interrupt_input_blocked; -extern int pending_atimers; +/* Begin critical section. */ +BLOCKINPUT_INLINE void +block_input (void) +{ + interrupt_input_blocked++; +} -/* 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 +extern void unblock_input (void); +extern void totally_unblock_input (void); +extern void unblock_input_to (int); /* In critical section ? */ -#define INPUT_BLOCKED_P (interrupt_input_blocked > 0) -/* Defined in keyboard.c */ -extern void reinvoke_input_signal (void); +BLOCKINPUT_INLINE bool +input_blocked_p (void) +{ + return 0 < interrupt_input_blocked; +} + +INLINE_HEADER_END #endif /* EMACS_BLOCKINPUT_H */ |