1 // Copyright (c) 2023 Uber Technologies, Inc. 2 // 3 // Permission is hereby granted, free of charge, to any person obtaining a copy 4 // of this software and associated documentation files (the "Software"), to deal 5 // in the Software without restriction, including without limitation the rights 6 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 7 // copies of the Software, and to permit persons to whom the Software is 8 // furnished to do so, subject to the following conditions: 9 // 10 // The above copyright notice and this permission notice shall be included in 11 // all copies or substantial portions of the Software. 12 // 13 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 14 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 15 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 16 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 17 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 18 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 19 // THE SOFTWARE. 20 21 package zapcore 22 23 import "sync" 24 25 type lazyWithCore struct { 26 Core 27 sync.Once 28 fields []Field 29 } 30 31 // NewLazyWith wraps a Core with a "lazy" Core that will only encode fields if 32 // the logger is written to (or is further chained in a lon-lazy manner). 33 func NewLazyWith(core Core, fields []Field) Core { 34 return &lazyWithCore{ 35 Core: core, 36 fields: fields, 37 } 38 } 39 40 func (d *lazyWithCore) initOnce() { 41 d.Once.Do(func() { 42 d.Core = d.Core.With(d.fields) 43 }) 44 } 45 46 func (d *lazyWithCore) With(fields []Field) Core { 47 d.initOnce() 48 return d.Core.With(fields) 49 } 50 51 func (d *lazyWithCore) Check(e Entry, ce *CheckedEntry) *CheckedEntry { 52 d.initOnce() 53 return d.Core.Check(e, ce) 54 } 55