github.com/vmware/govmomi@v0.43.0/govc/flags/common.go (about) 1 /* 2 Copyright (c) 2015-2023 VMware, Inc. All Rights Reserved. 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 package flags 17 18 import "sync" 19 20 // Key type for storing flag instances in a context.Context. 21 type flagKey string 22 23 // Type to help flags out with only registering/processing once. 24 type common struct { 25 register sync.Once 26 process sync.Once 27 } 28 29 func (c *common) RegisterOnce(fn func()) { 30 c.register.Do(fn) 31 } 32 33 func (c *common) ProcessOnce(fn func() error) (err error) { 34 c.process.Do(func() { 35 err = fn() 36 }) 37 return err 38 }