c/readline.c

   1 #include <stdlib.h>
   2 #include <stdio.h>
   3 #include <unistd.h>
   4
   5 #if USE_READLINE
   6   #include <readline/readline.h>
   7   #include <readline/history.h>
   8   #include <readline/tilde.h>
   9 #else
  10   #include <editline/readline.h>
  11   #include <editline/history.h>
  12 #endif
  13
  14 int history_loaded = 0;
  15
  16 char HISTORY_FILE[] = "~/.mal-history";
  17
  18 int load_history() {
  19     if (history_loaded) { return 0; }
  20     int ret;
  21     char *hf = tilde_expand(HISTORY_FILE);
  22     if (access(hf, F_OK) != -1) {
  23         // TODO: check if file exists first, use non-static path
  24 #if USE_READLINE
  25         ret = read_history(hf);
  26 #else
  27         FILE *fp = fopen(hf, "r");
  28         char *line = malloc(80); // getline reallocs as necessary
  29         size_t sz = 80;
  30         while ((ret = getline(&line, &sz, fp)) > 0) {
  31             add_history(line); // Add line to in-memory history
  32         }
  33         free(line);
  34         fclose(fp);
  35 #endif
  36         history_loaded = 1;
  37     }
  38     free(hf);
  39 }
  40
  41 int append_to_history() {
  42     char *hf = tilde_expand(HISTORY_FILE);
  43 #ifdef USE_READLINE
  44     append_history(1, hf);
  45 #else
  46     HIST_ENTRY *he = history_get(history_length-1);
  47     FILE *fp = fopen(hf, "a");
  48     if (fp) {
  49         fprintf(fp, "%s\n", he->line);
  50         fclose(fp);
  51     }
  52 #endif
  53     free(hf);
  54 }
  55
  56
  57 // line must be freed by caller
  58 char *_readline (char prompt[]) {
  59     char *line;
  60
  61     load_history();
  62
  63     line = readline(prompt);
  64     if (!line) return NULL; // EOF
  65     add_history(line); // Add input to in-memory history
  66
  67     append_to_history(); // Flush new line of history to disk
  68
  69     return line;
  70 }
  71