d4bbbc828d
Adds CompareAndSwap and Swap methods to String, Error, and Value, implemented by making use of Value.CompareAndSwap and Value.Swap added in Go 1.17. Following that, add CompareAndSwap to all other types with "CAS" methods and deprecate CAS in favor of CompareAndSwap, since that's the convention the standard library chose for these in Go 1.19.
229 lines
6.6 KiB
Go
229 lines
6.6 KiB
Go
// Copyright (c) 2020-2022 Uber Technologies, Inc.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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// gen-atomicint generates an atomic wrapper around an integer type.
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//
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// gen-atomicint -name Int32 -wrapped int32 -file out.go
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//
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// The generated wrapper will use the functions in the sync/atomic package
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// named after the generated type.
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package main
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import (
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"bytes"
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"errors"
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"flag"
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"fmt"
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"go/format"
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"io"
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"log"
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"os"
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"text/template"
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"time"
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)
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func main() {
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log.SetFlags(0)
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if err := run(os.Args[1:]); err != nil {
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log.Fatalf("%+v", err)
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}
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}
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func run(args []string) error {
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var opts struct {
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Name string
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Wrapped string
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File string
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Unsigned bool
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}
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flag := flag.NewFlagSet("gen-atomicint", flag.ContinueOnError)
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flag.StringVar(&opts.Name, "name", "", "name of the generated type (e.g. Int32)")
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flag.StringVar(&opts.Wrapped, "wrapped", "", "name of the wrapped type (e.g. int32)")
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flag.StringVar(&opts.File, "file", "", "output file path (default: stdout)")
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flag.BoolVar(&opts.Unsigned, "unsigned", false, "whether the type is unsigned")
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if err := flag.Parse(args); err != nil {
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return err
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}
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if len(opts.Name) == 0 || len(opts.Wrapped) == 0 {
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return errors.New("flags -name and -wrapped are required")
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}
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var w io.Writer = os.Stdout
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if file := opts.File; len(file) > 0 {
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f, err := os.Create(file)
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if err != nil {
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return fmt.Errorf("create %q: %v", file, err)
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}
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defer f.Close()
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w = f
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}
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data := struct {
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Name string
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Wrapped string
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Unsigned bool
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ToYear int
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}{
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Name: opts.Name,
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Wrapped: opts.Wrapped,
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Unsigned: opts.Unsigned,
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ToYear: time.Now().Year(),
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}
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var buff bytes.Buffer
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if err := _tmpl.Execute(&buff, data); err != nil {
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return fmt.Errorf("render template: %v", err)
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}
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bs, err := format.Source(buff.Bytes())
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if err != nil {
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return fmt.Errorf("reformat source: %v", err)
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}
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_, err = w.Write(bs)
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return err
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}
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var _tmpl = template.Must(template.New("value.go").Parse(`// @generated Code generated by gen-atomicint.
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// Copyright (c) 2020-{{.ToYear}} Uber Technologies, Inc.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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package atomic
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import (
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"encoding/json"
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"strconv"
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"sync/atomic"
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)
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// {{ .Name }} is an atomic wrapper around {{ .Wrapped }}.
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type {{ .Name }} struct {
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_ nocmp // disallow non-atomic comparison
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v {{ .Wrapped }}
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}
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// New{{ .Name }} creates a new {{ .Name }}.
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func New{{ .Name }}(val {{ .Wrapped }}) *{{ .Name }} {
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return &{{ .Name }}{v: val}
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}
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// Load atomically loads the wrapped value.
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func (i *{{ .Name }}) Load() {{ .Wrapped }} {
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return atomic.Load{{ .Name }}(&i.v)
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}
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// Add atomically adds to the wrapped {{ .Wrapped }} and returns the new value.
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func (i *{{ .Name }}) Add(delta {{ .Wrapped }}) {{ .Wrapped }} {
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return atomic.Add{{ .Name }}(&i.v, delta)
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}
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// Sub atomically subtracts from the wrapped {{ .Wrapped }} and returns the new value.
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func (i *{{ .Name }}) Sub(delta {{ .Wrapped }}) {{ .Wrapped }} {
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return atomic.Add{{ .Name }}(&i.v,
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{{- if .Unsigned -}}
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^(delta - 1)
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{{- else -}}
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-delta
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{{- end -}}
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)
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}
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// Inc atomically increments the wrapped {{ .Wrapped }} and returns the new value.
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func (i *{{ .Name }}) Inc() {{ .Wrapped }} {
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return i.Add(1)
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}
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// Dec atomically decrements the wrapped {{ .Wrapped }} and returns the new value.
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func (i *{{ .Name }}) Dec() {{ .Wrapped }} {
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return i.Sub(1)
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}
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// CAS is an atomic compare-and-swap.
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//
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// Deprecated: Use CompareAndSwap.
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func (i *{{ .Name }}) CAS(old, new {{ .Wrapped }}) (swapped bool) {
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return i.CompareAndSwap(old, new)
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}
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// CompareAndSwap is an atomic compare-and-swap.
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func (i *{{ .Name }}) CompareAndSwap(old, new {{ .Wrapped }}) (swapped bool) {
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return atomic.CompareAndSwap{{ .Name }}(&i.v, old, new)
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}
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// Store atomically stores the passed value.
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func (i *{{ .Name }}) Store(val {{ .Wrapped }}) {
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atomic.Store{{ .Name }}(&i.v, val)
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}
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// Swap atomically swaps the wrapped {{ .Wrapped }} and returns the old value.
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func (i *{{ .Name }}) Swap(val {{ .Wrapped }}) (old {{ .Wrapped }}) {
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return atomic.Swap{{ .Name }}(&i.v, val)
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}
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// MarshalJSON encodes the wrapped {{ .Wrapped }} into JSON.
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func (i *{{ .Name }}) MarshalJSON() ([]byte, error) {
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return json.Marshal(i.Load())
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}
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// UnmarshalJSON decodes JSON into the wrapped {{ .Wrapped }}.
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func (i *{{ .Name }}) UnmarshalJSON(b []byte) error {
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var v {{ .Wrapped }}
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if err := json.Unmarshal(b, &v); err != nil {
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return err
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}
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i.Store(v)
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return nil
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}
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// String encodes the wrapped value as a string.
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func (i *{{ .Name }}) String() string {
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v := i.Load()
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{{ if .Unsigned -}}
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return strconv.FormatUint(uint64(v), 10)
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{{- else -}}
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return strconv.FormatInt(int64(v), 10)
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{{- end }}
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}
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`))
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