ggit/src/file-revision.js

var spawn = require('child_process').spawn
var check = require('check-more-types')

module.exports = {
  getFileRevision: getFileRevision,
  getRepoRevision: getRepoRevision
}

// commit can be SHA-1 or symbolic master~3 type
// filename should be relative to repo root
function getFileRevision (commit, filename, cb) {
  check.verify.string(commit, 'missing commit code')
  check.verify.string(filename, 'missing filename')
  check.verify.fn(cb, 'expected function callback')

  filename = filename.replace(/\\/g, '/')

  var args = ['show', commit + ':' + filename]
  // console.log('getting file revision', args);
  var git = spawn('git', args)

  var contents = ''
  git.stdout.setEncoding('utf-8')
  git.stdout.on('data', function (data) {
    data.trim()
    // console.log(data);
    contents += data
  })

  git.stderr.setEncoding('utf-8')
  git.stderr.on('data', function (data) {
    throw new Error('Could not get file\n' + filename + '\n' + data)
  })

  git.on('exit', function () {
    cb(contents)
  })
}

function getRepoRevision (filename, cb) {
  getFileRevision('master', filename, cb)
}