/* herevents.c COPYRIGHT (c) 1997 Kapteyn Astronomical Institute University of Groningen - 9700 AV Groningen, The Netherlands Author: J.P. Terlouw */ #include "stdlib.h" #include "stddef.h" #include "taskcom.h" #include "notify.h" #include "herevents.h" #define New(type) ((type *)calloc(1,sizeof(type))) #define Delete(x) {free(x); x=NULL;} typedef struct _Callback { struct _Callback *next; /* link to next block */ HereventProc proc; /* callback function pointer */ int mask; /* event mask */ void *arg; /* client data */ } _Callback, *Callback; static Callback list=NULL; static int n_active=0; /* -------------------------------------------------------------------------- */ /* readevent */ /* -------------------------------------------------------------------------- */ static void readevent(ident id, int fd, void *arg) { UnitedEvent uevent; Event event=(Event)&uevent; Callback cb, *cbp, *next; if (read(fd, &uevent, sizeof(uevent))>0) { for (cbp=&list; *cbp; cbp=next) { cb = *cbp; next = &cb->next; if (cb->mask) { if (event->code & cb->mask) { cb->proc((ident)cb, event, cb->arg); } } else { next = cbp; *cbp = cb->next; Delete(cb); } } } } /* -------------------------------------------------------------------------- */ /* active */ /* -------------------------------------------------------------------------- */ static void active(int mode) { static ident id; static int fd; if (mode) { fd = notify(1); id = ScheduleRead(readevent,fd,NULL); } else { (void)notify(0); close(fd); Deschedule(&id); } } /* ========================================================================== */ /* ScheduleHerevent */ /* -------------------------------------------------------------------------- */ ident ScheduleHerevent(HereventProc proc, int mask, void *arg) { Callback cb=New(_Callback); if (!n_active++) active(1); cb->next = list; list = cb; cb->proc = proc; cb->mask = mask; cb->arg = arg; return (ident)cb; } /* ========================================================================== */ /* DescheduleHerevent */ /* -------------------------------------------------------------------------- */ extern void DescheduleHerevent(ident *id) { Callback cb=(Callback)*id; if (!*id) return; *id = NULL; cb->mask = 0; if (!--n_active) active(0); } /* ========================================================================== */ /* Herevents */ /* -------------------------------------------------------------------------- */ extern void Herevents(bool state) { if (n_active) active(state?1:0); } /* #> herevents.h #if !defined(_herevents_h_) #define _herevents_h_ #include "taskcom.h" #include "events.h" typedef void (*HereventProc)(ident, Event, void*); extern ident ScheduleHerevent(HereventProc proc, int mask, void *arg); extern void DescheduleHerevent(ident *id); extern void Herevents(bool state); #endif #< #> ScheduleHerevent.dc3 Function: ScheduleHerevent Purpose: Register a function to be called whenever Hermes generates an event meeting a specified mask. Category: SYSTEM File: herevents.c Author: J.P. Terlouw Use: #include "herevents.h" ident id; id = ScheduleHerevent(proc, mask, arg); HereventProc proc - pointer to function int mask - event mask: the bitwise OR of any of the events defined in taskcom.h void *arg - 'client' data Description: ScheduleHerevent registers a function to be called by MainLoop whenever Hermes generates an event which meets the specified mask. In this call, 'arg' will be passed to 'proc'. The return value is a unique identification code corresponding with the registration, which will also be passed as an argument to 'proc'. The prototype of 'proc' is: void proc(ident id, Event event, void *arg); The argument 'event' has the generic Hermes event type. Within 'proc' this should be cast to one or more specific event types. Example: The following program illustrates how the function can be used. #include "stdio.h" #include "cmain.h" #include "gipsyc.h" #include "init.h" #include "finis.h" #include "anyout.h" #include "herevents.h" static char message[80]; static fint zero=0; static void handle_key(ident id, Event event, void *arg) { KeyEvent keyevent=(KeyEvent)event; sprintf(message,"%s: %s", (char*)arg, keyevent->key); anyout_c(&zero,tofchar(message)); } static void handle_resume(ident id, Event event, void *arg) { ResEvent resevent=(ResEvent)event; anyout_c(&zero,tofchar("Resume after pause")); } static void handle_any(ident id, Event event, void *arg) { anyout_c(&zero,tofchar("Keychange or resume (only one message)")); DescheduleHerevent(&id); } MAIN_PROGRAM_ENTRY { init_c(); (void)ScheduleHerevent(handle_key, KEYCHANGE, "Keyword changed"); (void)ScheduleHerevent(handle_resume,RESEVENT,NULL); (void)ScheduleHerevent(handle_any,KEYCHANGE|RESEVENT,NULL); MainLoop(); finis_c(); return 0; } Related Docs: DescheduleHerevent.dc3, events.dc3 Updates: Apr 8, 1997: JPT, Document created. #< #> DescheduleHerevent.dc3 Function: DescheduleHerevent Purpose: De-register a function registered previously by ScheduleHerevent. Category: SYSTEM File: herevents.c Author: J.P. Terlouw Use: DescheduleHerevent(&id); ident id - registration identification code. Description: The function associated with 'id' is descheduled and 'id' is set to zero. (Note that the argument is a pointer to 'id'.) Related Doc: ScheduleHerevent.dc3 Updates: Apr 8, 1997: JPT, Document created. #< #> herevents.dc3 Document: herevents Purpose: Describes routines for handling Hermes events Category: SYSTEM File: herevents.c Author: J.P. Terlouw Description: The routines in this source allow a task to specify ("schedule") one or more functions to be called when Hermes generates a specified event. A Hermes event can be one of the following: - user input keyword change; - user input keyword cancel; - user input keyword reject; - task resume after suspend. These events and associated messages are defined in taskcom.h. The following routines are available: ScheduleHerevent - schedule function for receiving events DescheduleHerevent - deschedule function Herevents - control Hermes' event generation Related doc: MainLoop.dc2 #< #> Herevents.dc2 Function: Herevents Purpose: Control Hermes' event generation. Category: SYSTEM File: herevents.c Author: J.P. Terlouw Use: Herevents(state); bool state - determines whether events are generated or not. Description: This function can be used in event-driven tasks to temporarily prevent Hermes from generating events such as keyword events. This can be useful when the current interaction is exclusively controlled by an other event source, e.g. a a plotfield cursor. In such cases the responsiveness of the application may improve. Updates: Jun 26, 2000: JPT, Document created. #< */