js/node_readline.js

   1 // IMPORTANT: choose one
   2 var RL_LIB = "libreadline";  // NOTE: libreadline is GPL
   3 //var RL_LIB = "libedit";
   4
   5 var HISTORY_FILE = require('path').join(process.env.HOME, '.mal-history');
   6
   7 var rlwrap = {}; // namespace for this module in web context
   8
   9 var ffi = require('ffi-napi'),
  10     fs = require('fs');
  11
  12 var rllib = ffi.Library(RL_LIB, {
  13     'readline':    [ 'string', [ 'string' ] ],
  14     'add_history': [ 'int',    [ 'string' ] ]});
  15
  16 var rl_history_loaded = false;
  17
  18 exports.readline = rlwrap.readline = function(prompt) {
  19     prompt = typeof prompt !== 'undefined' ? prompt : "user> ";
  20
  21     if (!rl_history_loaded) {
  22         rl_history_loaded = true;
  23         var lines = [];
  24         if (fs.existsSync(HISTORY_FILE)) {
  25             lines = fs.readFileSync(HISTORY_FILE).toString().split("\n");
  26         }
  27         // Max of 2000 lines
  28         lines = lines.slice(Math.max(lines.length - 2000, 0));
  29         for (var i=0; i<lines.length; i++) {
  30             if (lines[i]) { rllib.add_history(lines[i]); }
  31         }
  32     }
  33
  34     var line = rllib.readline(prompt);
  35     if (line) {
  36         rllib.add_history(line);
  37         try {
  38             fs.appendFileSync(HISTORY_FILE, line + "\n");
  39         } catch (exc) {
  40             // ignored
  41         }
  42     }
  43
  44     return line;
  45 };
  46 var readline = exports;