+++ /dev/null
-/* -*-c-*-
- *
- * I/O multiplexing support
- *
- * (c) 1999 Straylight/Edgeware
- */
-
-/*----- Licensing notice --------------------------------------------------*
- *
- * This file is part of the mLib utilities library.
- *
- * mLib is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Library General Public License as
- * published by the Free Software Foundation; either version 2 of the
- * License, or (at your option) any later version.
- *
- * mLib 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 Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with mLib; if not, write to the Free
- * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
- * MA 02111-1307, USA.
- */
-
-#ifndef MLIB_SEL_H
-#define MLIB_SEL_H
-
-#ifdef __cplusplus
- extern "C" {
-#endif
-
-/*----- Theory lesson -----------------------------------------------------*
- *
- * Things which are expecting to do I/O or go off at a certain time are
- * called `selectors'. There are two types of selectors: `file selectors'
- * wait patiently for a file to become readable or writable; `timeout
- * selectors' wait for a certain amount of time to elapse. There is also a
- * `multiplexor' which copes with managing all of this stuff.
- *
- * Multiplexors aren't actually very interesting. You initialize them with
- * @sel_init@, and then add and remove selectors as you go. When you want to
- * wait for something to happen, call @sel_select@.
- *
- * A file selector can *either* read *or* write. It can't do both. This is
- * because you quite often want to read a socket but not write it; during
- * those times you don't want to write, you just don't install a write
- * selector.
- *
- * File selectors are called when their files are available for reading or
- * writing as appropriate, and given their file descriptor, the state of the
- * file, and a pointer that was registered along with the selector.
- *
- * File selectors are set up in two phases. First, they're `initialized'
- * with @sel_initfile@. An initialized file selector doesn't do anything.
- * It needs to be added to a multiplexor using `sel_addfile'. It can later
- * be removed using `sel_rmfile'. You can carry on adding and removing as
- * you wish. Just don't try adding it twice in a row.
- *
- * Timeout selectors are called at a certain time. (Actually, they're called
- * *after* a certain time.) There's no separate initialization step with
- * timouts: you just add them and they work. If you decide you don't want a
- * timeout to go off, then you just remove it. (Adding and removing the
- * *same* timeout isn't something you do very often. You usually use a
- * different expiry time each time.)
- */
-
-/*----- Header files ------------------------------------------------------*/
-
-#include <sys/types.h>
-#include <sys/time.h>
-#include <unistd.h>
-
-/*----- Data structures ---------------------------------------------------*/
-
-/* --- A multiplexor --- *
- *
- * The files are sorted in reverse order of file descriptor number; the
- * timers are in normal order of occurrence. Thus, the interesting one
- * is always at the front of the list.
- */
-
-enum {
- SEL_READ, /* File is ready to read */
- SEL_WRITE, /* File is ready to write */
- SEL_EXC, /* Something odd has happened */
- SEL_MODES /* Number of modes available */
-};
-
-typedef struct sel_state {
- struct sel_file *files[SEL_MODES]; /* Lists of interesting files */
- struct sel_timer *timers; /* List of timers */
- struct sel_hook *hooks; /* List of hook functions applied */
- fd_set fd[SEL_MODES]; /* Quick reference table for files */
- struct sel_args *args; /* Pointer to arguments */
-} sel_state;
-
-/* --- Listening for a file --- */
-
-typedef struct sel_file {
- struct sel_file *next; /* Next file in the list */
- struct sel_file **prev; /* Previous file in the list */
- struct sel_state *s; /* Pointer to select multiplexor */
- int fd; /* File descriptor */
- unsigned mode; /* Interesting event for file */
- void (*func)(int /*fd*/, unsigned /*mode*/, void */*p*/); /* Handler */
- void *p; /* Argument for the handler */
- struct sel_pendfile *pend; /* Pending file information */
-} sel_file;
-
-/* --- Waiting for a timeout --- */
-
-typedef struct sel_timer {
- struct sel_timer *next; /* Next timer in the list */
- struct sel_timer **prev; /* Previous timer in the list */
- struct timeval tv; /* Real time when timer should go */
- void (*func)(struct timeval */*tv*/, void */*p*/); /* Handler function */
- void *p; /* Argument for the handler */
- struct sel_pendtimer *pend; /* Pending timer information */
-} sel_timer;
-
-/* --- A select argument block --- */
-
-typedef struct sel_args {
- int maxfd; /* Highest-numbered file */
- fd_set fd[SEL_MODES]; /* Bit flags for all the files */
- struct timeval tv, *tvp; /* Time to return */
- struct timeval now; /* Current time */
-} sel_args;
-
-/* --- A selector hook --- *
- *
- * The hooks are called (in arbitrary order) on each select.
- */
-
-typedef void (*sel_hookfn)(sel_state */*s*/,
- sel_args */*a*/,
- void */*p*/);
-
-typedef struct sel_hook {
- struct sel_hook *next; /* Next hook in the list */
- struct sel_hook **prev; /* Previous hook in the list */
- sel_hookfn before, after; /* Hook functions */
- void *p; /* Argument for the hook functions */
-} sel_hook;
-
-/*----- Functions provided ------------------------------------------------*/
-
-/* --- @sel_init@ --- *
- *
- * Arguments: @sel_state *s@ = pointer to a state block to initialize
- *
- * Returns: ---
- *
- * Use: Initializes a select state block.
- */
-
-extern void sel_init(sel_state */*s*/);
-
-/* --- @sel_initfile@ --- *
- *
- * Arguments: @sel_state *s@ = select state to attach to
- * @sel_file *f@ = pointer to a file block to initialize
- * @int fd@ = the file descriptor to listen to
- * @unsigned mode@ = what to listen for
- * @void (*func)(int fd, unsigned mode, void *p)@ = handler
- * @void *p@ = argument to pass to handler
- *
- * Returns: ---
- *
- * Use: Initializes a file block ready for use. The file block
- * isn't added to the list of things to do until a call to
- * @sel_addfile@.
- */
-
-extern void sel_initfile(sel_state */*s*/, sel_file */*f*/,
- int /*fd*/, unsigned /*mode*/,
- void (*/*func*/)(int /*fd*/,
- unsigned /*mode*/,
- void */*p*/),
- void */*p*/);
-
-/* --- @sel_addfile@ --- *
- *
- * Arguments: @sel_file *f@ = pointer to a file block
- *
- * Returns: ---
- *
- * Use: Adds a file block into the list of things to listen to.
- */
-
-extern void sel_addfile(sel_file */*f*/);
-
-/* --- @sel_rmfile@ --- *
- *
- * Arguments: @sel_file *f@ = pointer to a file block
- *
- * Returns: ---
- *
- * Use: Removes a file block from the list of things to listen to.
- */
-
-extern void sel_rmfile(sel_file */*f*/);
-
-/* --- @sel_force@ --- *
- *
- * Arguments: @sel_file *f@ = pointer to file selector
- *
- * Returns: ---
- *
- * Use: Forces a file selector to be considered ready. This is only
- * useful during a call to @sel_select@. Of particular use is
- * forcing a write selector when there's something interesting
- * ready for it.
- */
-
-extern void sel_force(sel_file */*f*/);
-
-/* --- @sel_addtimer@ --- *
- *
- * Arguments: @sel_state *s@ = pointer to a state block
- * @sel_timer *t@ = pointer to a timer block
- * @struct timeval *tv@ = pointer to time to activate
- * @void *p@ = argument for handler function
- *
- * Returns: ---
- *
- * Use: Registers and sets up a timer.
- */
-
-extern void sel_addtimer(sel_state */*s*/, sel_timer */*t*/,
- struct timeval */*tv*/,
- void (*/*func*/)(struct timeval */*tv*/,
- void */*p*/),
- void */*p*/);
-
-/* --- @sel_rmtimer@ --- *
- *
- * Arguments: @sel_timer *t@ = pointer to timer block
- *
- * Returns: ---
- *
- * Use: Removes a timer from the list of timers.
- */
-
-extern void sel_rmtimer(sel_timer */*t*/);
-
-/* --- @sel_addhook@ --- *
- *
- * Arguments: @sel_state *s@ = pointer to state block
- * @sel_hook *h@ = pointer to hook block
- * @sel_hookfn before, after@ = hook functions
- * @void *p@ = pointer argument to pass to hook functions
- *
- * Returns: ---
- *
- * Use: Registers hook functions to be called on each select call.
- */
-
-extern void sel_addhook(sel_state */*s*/, sel_hook */*h*/,
- sel_hookfn /*before*/, sel_hookfn /*after*/,
- void */*p*/);
-
-/* --- @sel_rmhook@ --- *
- *
- * Arguments: @sel_hook *h@ = pointer to hook block
- *
- * Returns: ---
- *
- * Use: Removes hook functions.
- */
-
-extern void sel_rmhook(sel_hook */*h*/);
-
-/* --- @sel_fdmerge@ --- *
- *
- * Arguments: @fd_set *dest@ = destination FD set
- * @fd_set *fd@ = pointer to set to merge
- * @int maxfd@ = highest numbered descriptor in @fd@ + 1
- *
- * Returns: Actual highest numbered descriptor.
- *
- * Use: Merges file descriptor sets, and returns an accurate @maxfd@
- * value.
- */
-
-extern int sel_fdmerge(fd_set */*dest*/, fd_set */*fd*/, int /*maxfd*/);
-
-/* --- @sel_select@ --- *
- *
- * Arguments: @sel_state *s@ = pointer to state block
- *
- * Returns: Zero if all OK, -1 on error.
- *
- * Use: Does a @select@ call (or equivalent @poll@).
- */
-
-extern int sel_select(sel_state */*s*/);
-
-/*----- That's all, folks -------------------------------------------------*/
-
-#ifdef __cplusplus
- }
-#endif
-
-#endif
~mdw / mLib / blobdiff