Move "common/config" common types into cfgtypes.

common/config/projectName.go

-// Copyright 2016 The LUCI Authors. All rights reserved.
-// Use of this source code is governed under the Apache License, Version 2.0
-// that can be found in the LICENSE file.
-
-package config
-
-import (
-        "errors"
-        "flag"
-        "fmt"
-)
-
-// ProjectName is a luci-config project name.
-//
-// A valid project name may only include:
-//      - Lowercase letters [a-z]
-//      - Numbers [0-9]
-//      - Hyphen (-)
-//      - Underscore (_)
-//
-// It also must begin with a letter.
-//
-// See:
-// https://github.com/luci/luci-py/blob/8e594074929871a9761d27e814541bc0d7d84744/appengine/components/components/config/common.py#L41
-type ProjectName string
-
-var _ flag.Value = (*ProjectName)(nil)
-
-// Validate returns an error if the supplied ProjectName is not a valid project
-// name.
-func (p ProjectName) Validate() error {
-        if len(p) == 0 {
-                return errors.New("cannot have empty name")
-        }
-
-        for idx, r := range p {
-                switch {
-                case r >= 'a' && r <= 'z':
-
-                case (r >= '0' && r <= '9'), r == '-', r == '_':
-                        if idx == 0 {
-                                return errors.New("must begin with a letter")
-                        }
-
-                default:
-                        return fmt.Errorf("invalid character at %d (%c)", idx, r)
-                }
-        }
-
-        return nil
-}
-
-// String implements flag.Value.
-func (p *ProjectName) String() string {
-        return string(*p)
-}
-
-// Set implements flag.Value.
-func (p *ProjectName) Set(v string) error {
-        vp := ProjectName(v)
-        if err := vp.Validate(); err != nil {
-                return err
-        }
-        *p = vp
-        return nil
-}