node/deps/npm/lib/utils/git.js

// handle some git configuration for windows

exports.spawn = spawnGit
exports.chainableExec = chainableExec
exports.whichAndExec = whichAndExec

var exec = require('child_process').execFile
var spawn = require('./spawn')
var npm = require('../npm.js')
var which = require('which')
var git = npm.config.get('git')
var assert = require('assert')
var log = require('npmlog')

function prefixGitArgs () {
  return process.platform === 'win32' ? ['-c', 'core.longpaths=true'] : []
}

function execGit (args, options, cb) {
  log.info('git', args)
  var fullArgs = prefixGitArgs().concat(args || [])
  return exec(git, fullArgs, options, cb)
}

function spawnGit (args, options) {
  log.info('git', args)
  return spawn(git, prefixGitArgs().concat(args || []), options)
}

function chainableExec () {
  var args = Array.prototype.slice.call(arguments)
  return [execGit].concat(args)
}

function whichGit (cb) {
  return which(git, cb)
}

function whichAndExec (args, options, cb) {
  assert.equal(typeof cb, 'function', 'no callback provided')
  // check for git
  whichGit(function (err) {
    if (err) {
      err.code = 'ENOGIT'
      return cb(err)
    }

    execGit(args, options, cb)
  })
}