Blame view

node_modules/cross-spawn/lib/util/readShebang.js 894 Bytes
ce4c83ff   wxy   初始提交
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
  'use strict';
  
  var fs = require('fs');
  var LRU = require('lru-cache');
  var shebangCommand = require('shebang-command');
  
  var shebangCache = new LRU({ max: 50, maxAge: 30 * 1000 });  // Cache just for 30sec
  
  function readShebang(command) {
      var buffer;
      var fd;
      var shebang;
  
      // Check if it is in the cache first
      if (shebangCache.has(command)) {
          return shebangCache.get(command);
      }
  
      // Read the first 150 bytes from the file
      buffer = new Buffer(150);
  
      try {
          fd = fs.openSync(command, 'r');
          fs.readSync(fd, buffer, 0, 150, 0);
          fs.closeSync(fd);
      } catch (e) { /* empty */ }
  
      // Attempt to extract shebang (null is returned if not a shebang)
      shebang = shebangCommand(buffer.toString());
  
      // Store the shebang in the cache
      shebangCache.set(command, shebang);
  
      return shebang;
  }
  
  module.exports = readShebang;