[490] | 1 | #if 0 |
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| 2 | INDI |
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| 3 | Copyright (C) 2003 Elwood C. Downey |
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| 4 | |
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| 5 | This library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | This library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with this library; if not, write to the Free Software |
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| 17 | Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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| 18 | |
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| 19 | #endif |
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| 20 | |
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| 21 | /* suite of functions to implement an event driven program. |
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| 22 | * |
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| 23 | * callbacks may be registered that are triggered when a file descriptor |
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| 24 | * will not block when read; |
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| 25 | * |
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| 26 | * timers may be registered that will run no sooner than a specified delay from |
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| 27 | * the moment they were registered; |
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| 28 | * |
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| 29 | * work procedures may be registered that are called when there is nothing |
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| 30 | * else to do; |
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| 31 | * |
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| 32 | #define MAIN_TEST for a stand-alone test program. |
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| 33 | */ |
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| 34 | |
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| 35 | #include <stdio.h> |
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| 36 | #include <stdlib.h> |
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| 37 | #include <math.h> |
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| 38 | #include <string.h> |
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| 39 | #include <time.h> |
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| 40 | #include <sys/types.h> |
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| 41 | #include <sys/time.h> |
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| 42 | #include <unistd.h> |
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| 43 | |
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| 44 | #include "eventloop.h" |
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| 45 | |
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| 46 | /* info about one registered callback. |
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| 47 | * the malloced array cback is never shrunk, entries are reused. new id's are |
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| 48 | * the index of first unused slot in array (and thus reused like unix' open(2)). |
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| 49 | */ |
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| 50 | typedef struct { |
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| 51 | int in_use; /* flag to mark this record is active */ |
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| 52 | int fd; /* fd descriptor to watch for read */ |
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| 53 | void *ud; /* user's data handle */ |
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| 54 | CBF *fp; /* callback function */ |
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| 55 | } CB; |
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| 56 | static CB *cback; /* malloced list of callbacks */ |
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| 57 | static int ncback; /* n entries in cback[] */ |
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| 58 | static int ncbinuse; /* n entries in cback[] marked in_use */ |
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| 59 | static int lastcb; /* cback index of last cb called */ |
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| 60 | |
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| 61 | /* info about one registered timer function. |
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| 62 | * the entries are kept sorted by decreasing time from epoch, ie, |
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| 63 | * the next entry to fire is at the end of the array. |
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| 64 | */ |
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| 65 | typedef struct { |
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| 66 | double tgo; /* trigger time, ms from epoch */ |
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| 67 | void *ud; /* user's data handle */ |
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| 68 | TCF *fp; /* timer function */ |
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| 69 | int tid; /* unique id for this timer */ |
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| 70 | } TF; |
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| 71 | static TF *timef; /* malloced list of timer functions */ |
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| 72 | static int ntimef; /* n entries in ntimef[] */ |
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| 73 | static int tid; /* source of unique timer ids */ |
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| 74 | #define EPOCHDT(tp) /* ms from epoch to timeval *tp */ \ |
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| 75 | (((tp)->tv_usec)/1000.0 + ((tp)->tv_sec)*1000.0) |
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| 76 | |
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| 77 | /* info about one registered work procedure. |
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| 78 | * the malloced array wproc is never shrunk, entries are reused. new id's are |
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| 79 | * the index of first unused slot in array (and thus reused like unix' open(2)). |
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| 80 | */ |
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| 81 | typedef struct { |
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| 82 | int in_use; /* flag to mark this record is active */ |
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| 83 | void *ud; /* user's data handle */ |
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| 84 | WPF *fp; /* work proc function function */ |
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| 85 | } WP; |
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| 86 | static WP *wproc; /* malloced list of work procedures */ |
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| 87 | static int nwproc; /* n entries in wproc[] */ |
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| 88 | static int nwpinuse; /* n entries in wproc[] marked in-use */ |
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| 89 | static int lastwp; /* wproc index of last workproc called*/ |
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| 90 | |
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| 91 | static void runWorkProc (void); |
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| 92 | static void callCallback(fd_set *rfdp); |
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| 93 | static void checkTimer(); |
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| 94 | static void oneLoop(void); |
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| 95 | static void deferTO (void *p); |
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| 96 | |
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| 97 | /* inf loop to dispatch callbacks, work procs and timers as necessary. |
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| 98 | * never returns. |
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| 99 | */ |
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| 100 | void |
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| 101 | eventLoop() |
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| 102 | { |
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| 103 | /* run loop forever */ |
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| 104 | while (1) |
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| 105 | oneLoop(); |
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| 106 | } |
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| 107 | |
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| 108 | /* allow other timers/callbacks/workprocs to run until time out in maxms |
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| 109 | * or *flagp becomes non-0. wait forever if maxms is 0. |
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| 110 | * return 0 if flag did flip, else -1 if never changed and we timed out. |
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| 111 | * the expected usage for this is for the caller to arrange for a T/C/W to set |
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| 112 | * a flag, then give caller an in-line way to wait for the flag to change. |
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| 113 | */ |
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| 114 | int |
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| 115 | deferLoop (int maxms, int *flagp) |
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| 116 | { |
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| 117 | int toflag = 0; |
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| 118 | int totid = maxms ? addTimer (maxms, deferTO, &toflag) : 0; |
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| 119 | |
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| 120 | while (!*flagp) { |
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| 121 | oneLoop(); |
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| 122 | if (toflag) |
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| 123 | return (-1); /* totid already dead */ |
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| 124 | } |
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| 125 | |
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| 126 | if (totid) |
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| 127 | rmTimer (totid); |
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| 128 | return (0); |
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| 129 | } |
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| 130 | |
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| 131 | /* allow other timers/callbacks/workprocs to run until time out in maxms |
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| 132 | * or *flagp becomes 0. wait forever if maxms is 0. |
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| 133 | * return 0 if flag did flip, else -1 if never changed and we timed out. |
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| 134 | * the expected usage for this is for the caller to arrange for a T/C/W to set |
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| 135 | * a flag, then give caller an in-line way to wait for the flag to change. |
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| 136 | */ |
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| 137 | int |
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| 138 | deferLoop0 (int maxms, int *flagp) |
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| 139 | { |
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| 140 | int toflag = 0; |
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| 141 | int totid = maxms ? addTimer (maxms, deferTO, &toflag) : 0; |
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| 142 | |
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| 143 | while (*flagp) { |
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| 144 | oneLoop(); |
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| 145 | if (toflag) |
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| 146 | return (-1); /* totid already dead */ |
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| 147 | } |
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| 148 | |
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| 149 | if (totid) |
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| 150 | rmTimer (totid); |
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| 151 | return (0); |
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| 152 | } |
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| 153 | |
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| 154 | /* register a new callback, fp, to be called with ud as arg when fd is ready. |
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| 155 | * return a unique callback id for use with rmCallback(). |
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| 156 | */ |
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| 157 | int |
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| 158 | addCallback (int fd, CBF *fp, void *ud) |
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| 159 | { |
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| 160 | CB *cp; |
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| 161 | |
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| 162 | /* reuse first unused slot or grow */ |
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| 163 | for (cp = cback; cp < &cback[ncback]; cp++) |
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| 164 | if (!cp->in_use) |
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| 165 | break; |
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| 166 | if (cp == &cback[ncback]) { |
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| 167 | cback = cback ? (CB *) realloc (cback, (ncback+1)*sizeof(CB)) |
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| 168 | : (CB *) malloc (sizeof(CB)); |
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| 169 | cp = &cback[ncback++]; |
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| 170 | } |
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| 171 | |
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| 172 | /* init new entry */ |
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| 173 | cp->in_use = 1; |
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| 174 | cp->fp = fp; |
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| 175 | cp->ud = ud; |
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| 176 | cp->fd = fd; |
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| 177 | ncbinuse++; |
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| 178 | |
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| 179 | /* id is index into array */ |
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| 180 | return (cp - cback); |
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| 181 | } |
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| 182 | |
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| 183 | /* remove the callback with the given id, as returned from addCallback(). |
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| 184 | * silently ignore if id not valid. |
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| 185 | */ |
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| 186 | void |
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| 187 | rmCallback (int cid) |
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| 188 | { |
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| 189 | CB *cp; |
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| 190 | |
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| 191 | /* validate id */ |
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| 192 | if (cid < 0 || cid >= ncback) |
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| 193 | return; |
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| 194 | cp = &cback[cid]; |
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| 195 | if (!cp->in_use) |
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| 196 | return; |
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| 197 | |
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| 198 | /* mark for reuse */ |
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| 199 | cp->in_use = 0; |
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| 200 | ncbinuse--; |
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| 201 | } |
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| 202 | |
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| 203 | /* register a new timer function, fp, to be called with ud as arg after ms |
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| 204 | * milliseconds. add to list in order of decreasing time from epoch, ie, |
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| 205 | * last entry runs soonest. return id for use with rmTimer(). |
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| 206 | */ |
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| 207 | int |
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| 208 | addTimer (int ms, TCF *fp, void *ud) |
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| 209 | { |
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| 210 | struct timeval t; |
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| 211 | TF *tp; |
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| 212 | |
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| 213 | /* get time now */ |
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| 214 | gettimeofday (&t, NULL); |
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| 215 | |
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| 216 | /* add one entry */ |
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| 217 | timef = timef ? (TF *) realloc (timef, (ntimef+1)*sizeof(TF)) |
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| 218 | : (TF *) malloc (sizeof(TF)); |
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| 219 | tp = &timef[ntimef++]; |
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| 220 | |
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| 221 | /* init new entry */ |
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| 222 | tp->ud = ud; |
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| 223 | tp->fp = fp; |
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| 224 | tp->tgo = EPOCHDT(&t) + ms; |
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| 225 | |
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| 226 | /* insert maintaining sort */ |
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| 227 | for ( ; tp > timef && tp[0].tgo > tp[-1].tgo; tp--) { |
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| 228 | TF tmptf = tp[-1]; |
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| 229 | tp[-1] = tp[0]; |
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| 230 | tp[0] = tmptf; |
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| 231 | } |
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| 232 | |
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| 233 | /* store and return new unique id */ |
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| 234 | return (tp->tid = ++tid); |
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| 235 | } |
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| 236 | |
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| 237 | /* remove the timer with the given id, as returned from addTimer(). |
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| 238 | * silently ignore if id not found. |
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| 239 | */ |
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| 240 | void |
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| 241 | rmTimer (int timer_id) |
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| 242 | { |
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| 243 | TF *tp; |
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| 244 | |
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| 245 | /* find it */ |
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| 246 | for (tp = timef; tp < &timef[ntimef]; tp++) |
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| 247 | if (tp->tid == timer_id) |
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| 248 | break; |
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| 249 | if (tp == &timef[ntimef]) |
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| 250 | return; |
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| 251 | |
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| 252 | /* bubble it out */ |
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| 253 | for (++tp; tp < &timef[ntimef]; tp++) |
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| 254 | tp[-1] = tp[0]; |
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| 255 | |
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| 256 | /* shrink list */ |
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| 257 | timef = (TF *) realloc (timef, (--ntimef)*sizeof(TF)); |
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| 258 | } |
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| 259 | |
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| 260 | /* add a new work procedure, fp, to be called with ud when nothing else to do. |
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| 261 | * return unique id for use with rmWorkProc(). |
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| 262 | */ |
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| 263 | int |
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| 264 | addWorkProc (WPF *fp, void *ud) |
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| 265 | { |
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| 266 | WP *wp; |
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| 267 | |
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| 268 | /* reuse first unused slot or grow */ |
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| 269 | for (wp = wproc; wp < &wproc[nwproc]; wp++) |
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| 270 | if (!wp->in_use) |
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| 271 | break; |
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| 272 | if (wp == &wproc[nwproc]) { |
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| 273 | wproc = wproc ? (WP *) realloc (wproc, (nwproc+1)*sizeof(WP)) |
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| 274 | : (WP *) malloc (sizeof(WP)); |
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| 275 | wp = &wproc[nwproc++]; |
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| 276 | } |
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| 277 | |
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| 278 | /* init new entry */ |
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| 279 | wp->in_use = 1; |
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| 280 | wp->fp = fp; |
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| 281 | wp->ud = ud; |
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| 282 | nwpinuse++; |
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| 283 | |
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| 284 | /* id is index into array */ |
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| 285 | return (wp - wproc); |
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| 286 | } |
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| 287 | |
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| 288 | |
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| 289 | /* remove the work proc with the given id, as returned from addWorkProc(). |
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| 290 | * silently ignore if id not found. |
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| 291 | */ |
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| 292 | void |
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| 293 | rmWorkProc (int wid) |
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| 294 | { |
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| 295 | WP *wp; |
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| 296 | |
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| 297 | /* validate id */ |
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| 298 | if (wid < 0 || wid >= nwproc) |
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| 299 | return; |
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| 300 | wp = &wproc[wid]; |
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| 301 | if (!wp->in_use) |
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| 302 | return; |
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| 303 | |
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| 304 | /* mark for reuse */ |
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| 305 | wp->in_use = 0; |
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| 306 | nwpinuse--; |
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| 307 | } |
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| 308 | |
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| 309 | /* run next work procedure */ |
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| 310 | static void |
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| 311 | runWorkProc () |
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| 312 | { |
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| 313 | WP *wp; |
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| 314 | |
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| 315 | /* skip if list is empty */ |
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| 316 | if (!nwpinuse) |
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| 317 | return; |
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| 318 | |
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| 319 | /* find next */ |
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| 320 | do { |
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| 321 | lastwp = (lastwp+1) % nwproc; |
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| 322 | wp = &wproc[lastwp]; |
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| 323 | } while (!wp->in_use); |
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| 324 | |
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| 325 | /* run */ |
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| 326 | (*wp->fp) (wp->ud); |
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| 327 | } |
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| 328 | |
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| 329 | /* run next callback whose fd is listed as ready to go in rfdp */ |
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| 330 | static void |
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| 331 | callCallback(fd_set *rfdp) |
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| 332 | { |
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| 333 | CB *cp; |
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| 334 | |
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| 335 | /* skip if list is empty */ |
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| 336 | if (!ncbinuse) |
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| 337 | return; |
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| 338 | |
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| 339 | /* find next */ |
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| 340 | do { |
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| 341 | lastcb = (lastcb+1) % ncback; |
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| 342 | cp = &cback[lastcb]; |
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| 343 | } while (!cp->in_use || !FD_ISSET (cp->fd, rfdp)); |
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| 344 | |
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| 345 | /* run */ |
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| 346 | (*cp->fp) (cp->fd, cp->ud); |
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| 347 | } |
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| 348 | |
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| 349 | /* run the next timer callback whose time has come, if any. all we have to do |
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| 350 | * is is check the last entry in timef[] because it is sorted in decreasing |
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| 351 | * order of time from epoch to run, ie, last entry runs soonest. |
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| 352 | */ |
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| 353 | static void |
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| 354 | checkTimer() |
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| 355 | { |
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| 356 | struct timeval now; |
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| 357 | double tgonow; |
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| 358 | TF *tp; |
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| 359 | |
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| 360 | /* skip if list is empty */ |
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| 361 | if (!ntimef) |
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| 362 | return; |
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| 363 | |
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| 364 | gettimeofday (&now, NULL); |
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| 365 | tgonow = EPOCHDT (&now); |
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| 366 | tp = &timef[ntimef-1]; |
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| 367 | if (tp->tgo <= tgonow) { |
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| 368 | ntimef--; /* pop then call */ |
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| 369 | (*tp->fp) (tp->ud); |
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| 370 | } |
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| 371 | } |
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| 372 | |
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| 373 | /* check fd's from each active callback. |
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| 374 | * if any ready, call their callbacks else call each registered work procedure. |
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| 375 | */ |
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| 376 | static void |
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| 377 | oneLoop() |
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| 378 | { |
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| 379 | struct timeval tv, *tvp; |
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| 380 | fd_set rfd; |
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| 381 | CB *cp; |
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| 382 | int maxfd, ns; |
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| 383 | |
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| 384 | /* build list of callback file descriptors to check */ |
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| 385 | FD_ZERO (&rfd); |
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| 386 | maxfd = -1; |
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| 387 | for (cp = cback; cp < &cback[ncback]; cp++) { |
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| 388 | if (cp->in_use) { |
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| 389 | FD_SET (cp->fd, &rfd); |
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| 390 | if (cp->fd > maxfd) |
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| 391 | maxfd = cp->fd; |
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| 392 | } |
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| 393 | } |
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| 394 | |
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| 395 | /* determine timeout: |
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| 396 | * if there are work procs |
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| 397 | * set delay = 0 |
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| 398 | * else if there is at least one timer func |
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| 399 | * set delay = time until soonest timer func expires |
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| 400 | * else |
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| 401 | * set delay = forever |
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| 402 | */ |
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| 403 | if (nwpinuse > 0) { |
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| 404 | tvp = &tv; |
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| 405 | tvp->tv_sec = tvp->tv_usec = 0; |
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| 406 | } else if (ntimef > 0) { |
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| 407 | struct timeval now; |
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| 408 | double late; |
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| 409 | gettimeofday (&now, NULL); |
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| 410 | late = timef[ntimef-1].tgo - EPOCHDT (&now); /* ms late */ |
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| 411 | if (late < 0) |
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| 412 | late = 0; |
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| 413 | late /= 1000.0; /* secs late */ |
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| 414 | tvp = &tv; |
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| 415 | tvp->tv_sec = (long)floor(late); |
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| 416 | tvp->tv_usec = (long)floor((late - tvp->tv_sec)*1000000.0); |
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| 417 | } else |
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| 418 | tvp = NULL; |
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| 419 | |
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| 420 | /* check file descriptors, timeout depending on pending work */ |
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| 421 | ns = select (maxfd+1, &rfd, NULL, NULL, tvp); |
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| 422 | if (ns < 0) { |
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| 423 | perror ("select"); |
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| 424 | exit(1); |
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| 425 | } |
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| 426 | |
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| 427 | /* dispatch */ |
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| 428 | checkTimer(); |
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| 429 | if (ns == 0) |
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| 430 | runWorkProc(); |
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| 431 | else |
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| 432 | callCallback(&rfd); |
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| 433 | } |
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| 434 | |
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| 435 | /* timer callback used to implement deferLoop(). |
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| 436 | * arg is pointer to int which we set to 1 |
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| 437 | */ |
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| 438 | static void |
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| 439 | deferTO (void *p) |
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| 440 | { |
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| 441 | *(int*)p = 1; |
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| 442 | } |
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| 443 | |
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| 444 | #if defined(MAIN_TEST) |
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| 445 | /* make a small stand-alone test program. |
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| 446 | */ |
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| 447 | |
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| 448 | #include <unistd.h> |
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| 449 | #include <sys/time.h> |
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| 450 | |
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| 451 | int mycid; |
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| 452 | int mywid; |
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| 453 | int mytid; |
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| 454 | |
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| 455 | int user_a; |
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| 456 | int user_b; |
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| 457 | int counter; |
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| 458 | |
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| 459 | void |
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| 460 | wp (void *ud) |
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| 461 | { |
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| 462 | struct timeval tv; |
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| 463 | |
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| 464 | gettimeofday (&tv, NULL); |
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| 465 | printf ("workproc @ %ld.%03ld %d %d\n", |
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| 466 | (long)tv.tv_sec, (long)tv.tv_usec/1000, counter, ++(*(int*)ud)); |
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| 467 | } |
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| 468 | |
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| 469 | void |
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| 470 | to (void *ud) |
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| 471 | { |
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| 472 | printf ("timeout %d\n", (int)ud); |
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| 473 | } |
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| 474 | |
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| 475 | void |
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| 476 | stdinCB (int fd, void *ud) |
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| 477 | { |
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| 478 | char c; |
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| 479 | |
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| 480 | if (read (fd, &c, 1) != 1) { |
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| 481 | perror ("read"); |
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| 482 | exit(1); |
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| 483 | } |
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| 484 | |
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| 485 | switch (c) { |
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| 486 | case '+': counter++; break; |
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| 487 | case '-': counter--; break; |
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| 488 | |
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| 489 | case 'W': mywid = addWorkProc (wp, &user_b); break; |
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| 490 | case 'w': rmWorkProc (mywid); break; |
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| 491 | |
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| 492 | case 'c': rmCallback (mycid); break; |
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| 493 | |
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| 494 | case 't': rmTimer (mytid); break; |
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| 495 | case '1': mytid = addTimer (1000, to, (void *)1); break; |
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| 496 | case '2': mytid = addTimer (2000, to, (void *)2); break; |
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| 497 | case '3': mytid = addTimer (3000, to, (void *)3); break; |
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| 498 | case '4': mytid = addTimer (4000, to, (void *)4); break; |
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| 499 | case '5': mytid = addTimer (5000, to, (void *)5); break; |
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| 500 | default: return; /* silently absorb other chars like \n */ |
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| 501 | } |
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| 502 | |
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| 503 | printf ("callback: %d\n", ++(*(int*)ud)); |
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| 504 | } |
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| 505 | |
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| 506 | int |
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| 507 | main (int ac, char *av[]) |
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| 508 | { |
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| 509 | (void) addCallback (0, stdinCB, &user_a); |
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| 510 | eventLoop(); |
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| 511 | exit(0); |
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| 512 | } |
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| 513 | |
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| 514 | #endif |
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| 515 | |
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