Simplifying async call pattern with forking

async.coffee

commit = =>
  @exec 'git', ['add', '.'], {}, null, (err) =>
    return callback err if err
    @exec 'git', ['commit', '-am', 'upd'], {}, null, (err, data) =>
      return callback err if err
      @head (err, sha) ->
        return callback err if err
        callback null, sha

asyncWithFork.coffee

commit = =>
  @exec 'git', ['add', '.'], {}, null, fork callback, =>        
    @exec 'git', ['commit', '-am', 'upd'], {}, null, fork callback, (data) =>          
      @head fork callback, (sha) ->            
        callback null, sha

difference.diff

@@ -19,8 +20,7 @@ createParentDirs = (base, path, callback) ->
       if exists
         checkNext()
       else
-        fs.mkdir path, (err) ->
-          return callback err if err
+        fs.mkdir path, fork callback, ->
           checkNext()
   checkNext()
 
@@ -33,17 +33,14 @@ deleteParentDirs = (base, path, callback) ->
     return callback null if index == paths.length
     path = base + '/' + paths[0..(path.length - index - 1)].join('/')
     index += 1
-    fs.readdir path, (err, list) ->
-      return callback err if err
+    fs.readdir path, fork callback, (list) ->
       if list.length == 0
-        fs.rmdir path, (err) ->
-          return callback err if err
+        fs.rmdir path, fork callback, ->
           checkNext()
       else
         callback()
   checkNext()