scheduler.c

Basic task scheduling library
git clone git://git.finwo.net/lib/scheduler.c
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example_io.c (1916B)

      1 #include <errno.h>
      2 #include <fcntl.h>
      3 #include <stdio.h>
      4 #include <stdlib.h>
      5 #include <string.h>
      6 #include <sys/time.h>
      7 #include <time.h>
      8 #include <unistd.h>
      9 
     10 #include "src/scheduler.h"
     11 
     12 typedef struct {
     13   int     pipe_fd;
     14   int     fds[2];
     15   int64_t last_write;
     16 } WriterCtx;
     17 
     18 typedef struct {
     19   int pipe_fd;
     20   int fds[2];
     21   int done;
     22 } ReaderCtx;
     23 
     24 static int writer_task(int64_t ts, pt_task_t *task) {
     25   static int count = 0;
     26   WriterCtx *ctx   = task->udata;
     27 
     28   if (ts - ctx->last_write >= 200) {
     29     char msg[32];
     30     int  len = snprintf(msg, sizeof(msg), "message #%d\n", ++count);
     31     write(ctx->pipe_fd, msg, len);
     32     ctx->last_write = ts;
     33 
     34     if (count >= 3) {
     35       snprintf(msg, sizeof(msg), "quit\n");
     36       write(ctx->pipe_fd, msg, 4);
     37       close(ctx->pipe_fd);
     38       free(ctx);
     39       return SCHED_DONE;
     40     }
     41   }
     42 
     43   return SCHED_RUNNING;
     44 }
     45 
     46 static int reader_task(int64_t ts, pt_task_t *task) {
     47   (void)ts;
     48   ReaderCtx *ctx = task->udata;
     49 
     50   int ready = sched_has_data(ctx->fds);
     51   if (ready >= 0) {
     52     char    buf[256];
     53     ssize_t n = read(ready, buf, sizeof(buf) - 1);
     54     if (n > 0) {
     55       buf[n] = '\0';
     56       printf("[reader] %s", buf);
     57     }
     58     if (n == 0 || (n > 0 && strncmp(buf, "quit\n", 5) == 0)) {
     59       ctx->done = 1;
     60     }
     61   }
     62 
     63   if (ctx->done) {
     64     close(ctx->pipe_fd);
     65     free(ctx);
     66     return SCHED_DONE;
     67   }
     68 
     69   return SCHED_RUNNING;
     70 }
     71 
     72 int main(void) {
     73   int pipefd[2];
     74   if (pipe(pipefd) < 0) {
     75     perror("pipe");
     76     return 1;
     77   }
     78 
     79   WriterCtx *wctx = calloc(1, sizeof(WriterCtx));
     80   wctx->pipe_fd   = pipefd[1];
     81 
     82   ReaderCtx *rctx = calloc(1, sizeof(ReaderCtx));
     83   rctx->pipe_fd   = pipefd[0];
     84   rctx->fds[0]    = 1;
     85   rctx->fds[1]    = rctx->pipe_fd;
     86 
     87   struct timeval now;
     88   gettimeofday(&now, NULL);
     89   wctx->last_write = (int64_t)now.tv_sec * 1000 + now.tv_usec / 1000;
     90 
     91   sched_create(writer_task, wctx);
     92   sched_create(reader_task, rctx);
     93   sched_main();
     94   return 0;
     95 }