testing/dispatch_read2.c

   1 #include <sys/stat.h>
   2 #include <assert.h>
   3 #include <fcntl.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <unistd.h>
   7 #include <errno.h>
   8
   9 #include <dispatch/dispatch.h>
  10
  11 #include "dispatch_test.h"
  12
  13 static size_t bytes_total;
  14 static size_t bytes_read;
  15
  16 int main(void)
  17 {
  18         const char *path = "/usr/share/dict/words";
  19         struct stat sb;
  20
  21         test_start("Dispatch Source Read");
  22
  23         int infd = open(path, O_RDONLY);
  24         if (infd == -1) {
  25                 perror(path);
  26                 exit(EXIT_FAILURE);
  27         }
  28         if (fstat(infd, &sb) == -1) {
  29                 perror(path);
  30                 exit(EXIT_FAILURE);
  31         }
  32         bytes_total = sb.st_size;
  33
  34         if (fcntl(infd, F_SETFL, O_NONBLOCK) != 0) {
  35                 perror(path);
  36                 exit(EXIT_FAILURE);
  37         }
  38
  39         dispatch_queue_t main_q = dispatch_get_main_queue();
  40         test_ptr_notnull("dispatch_get_main_queue", main_q);
  41
  42         dispatch_source_t reader = dispatch_source_create(DISPATCH_SOURCE_TYPE_READ, infd, 0, main_q);
  43         test_ptr_notnull("dispatch_source_create", reader);
  44         assert(reader);
  45
  46         dispatch_source_set_event_handler(reader, ^{
  47                         size_t estimated = dispatch_source_get_data(reader);
  48                         printf("bytes available: %zu\n", estimated);
  49                         const ssize_t bufsiz = 1024*500; // 500 KB buffer
  50                         static char buffer[1024*500];   // 500 KB buffer
  51                         ssize_t actual = read(infd, buffer, sizeof(buffer));
  52                         bytes_read += actual;
  53                         printf("bytes read: %zd\n", actual);
  54                         if (actual < bufsiz) {
  55                                 actual = read(infd, buffer, sizeof(buffer));
  56                                 bytes_read += actual;
  57                                 // confirm EOF condition
  58                                 test_long("EOF", actual, 0);
  59                                 dispatch_source_cancel(reader);
  60                         }
  61         });
  62         dispatch_source_set_cancel_handler(reader, ^{
  63                 test_long("Bytes read", bytes_read, bytes_total);
  64                 test_stop();
  65         });
  66         dispatch_resume(reader);
  67
  68         dispatch_main();
  69 }