git.scottworley.com Git - tl-append/blob - tl-append.c

   1 #define _POSIX_C_SOURCE 199309L
   2
   3 #include <errno.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <time.h>
   8 #include <unistd.h>
   9
  10 #include "common.h"
  11
  12 const size_t BUF_SIZE = 1024;
  13
  14 const char PROMPT[] = "\33[H" /* Move cursor 'home' */
  15                       "\33[J" /* Clear screen */
  16                       "> ";
  17 const char ACKNOWLEDGE[] = "[OK]";
  18 const struct timespec ACKNOWLEDGE_DELAY = {0, 300000000};
  19
  20 typedef struct {
  21   int interactive;
  22 } conf_t;
  23
  24 conf_t parse_command_line(int argc, char *argv[]) {
  25   conf_t conf = {0};
  26
  27   if (argc == 2 && strcmp(argv[1], "-i") == 0 && isatty(2))
  28     conf.interactive = 1;
  29
  30   return conf;
  31 }
  32
  33 static void read_line(conf_t conf, char *buf) {
  34   if (conf.interactive)
  35     if (fputs(PROMPT, stderr) == EOF)
  36       die("I/O error writing prompt");
  37   if (fgets(buf, BUF_SIZE, stdin) == NULL) {
  38     if (ferror(stdin))
  39       die("I/O error reading line");
  40     if (feof(stdin)) {
  41       buf[0] = '\0'; /* Unclear if fgets does this already */
  42       return;
  43     }
  44     die("Unexpected error reading line");
  45   }
  46 }
  47
  48 static void write_line(conf_t conf, const char *line) {
  49   const char *now = encode_time(time(NULL));
  50   FILE *f = fopen(FILENAME, "a");
  51   if (f == NULL)
  52     die_err("Error opening output file");
  53   if (fputs(now, f) == EOF)
  54     die("Error writing to output file");
  55   if (fputc(' ', f) == EOF)
  56     die("Error writing to output file");
  57   if (fputs(line, f) == EOF)
  58     die("Error writing to output file");
  59   if (fclose(f) != 0)
  60     die_err("Error closing output file");
  61   if (conf.interactive) {
  62     if (fputs(ACKNOWLEDGE, stderr) == EOF)
  63       die("Error writing acknowledgment");
  64     if (nanosleep(&ACKNOWLEDGE_DELAY, NULL) == -1 && errno != EINTR)
  65       die_err("Error sleeping");
  66   }
  67 }
  68
  69 int main(int argc, char *argv[]) {
  70   conf_t conf = parse_command_line(argc, argv);
  71   char buf[BUF_SIZE];
  72   for (read_line(conf, buf); buf[0]; read_line(conf, buf)) {
  73     write_line(conf, buf);
  74   }
  75   return 0;
  76 }