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restic/vendor/github.com/google/go-cmp/cmp/cmpopts/ignore.go

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2017-12-23 12:02:03 +00:00
// Copyright 2017, The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE.md file.
package cmpopts
import (
"fmt"
"reflect"
"unicode"
"unicode/utf8"
"github.com/google/go-cmp/cmp"
)
// IgnoreFields returns an Option that ignores exported fields of the
// given names on a single struct type.
// The struct type is specified by passing in a value of that type.
//
// The name may be a dot-delimited string (e.g., "Foo.Bar") to ignore a
// specific sub-field that is embedded or nested within the parent struct.
//
// This does not handle unexported fields; use IgnoreUnexported instead.
func IgnoreFields(typ interface{}, names ...string) cmp.Option {
sf := newStructFilter(typ, names...)
return cmp.FilterPath(sf.filter, cmp.Ignore())
}
// IgnoreTypes returns an Option that ignores all values assignable to
// certain types, which are specified by passing in a value of each type.
func IgnoreTypes(typs ...interface{}) cmp.Option {
tf := newTypeFilter(typs...)
return cmp.FilterPath(tf.filter, cmp.Ignore())
}
type typeFilter []reflect.Type
func newTypeFilter(typs ...interface{}) (tf typeFilter) {
for _, typ := range typs {
t := reflect.TypeOf(typ)
if t == nil {
// This occurs if someone tries to pass in sync.Locker(nil)
panic("cannot determine type; consider using IgnoreInterfaces")
}
tf = append(tf, t)
}
return tf
}
func (tf typeFilter) filter(p cmp.Path) bool {
if len(p) < 1 {
return false
}
t := p[len(p)-1].Type()
for _, ti := range tf {
if t.AssignableTo(ti) {
return true
}
}
return false
}
// IgnoreInterfaces returns an Option that ignores all values or references of
// values assignable to certain interface types. These interfaces are specified
// by passing in an anonymous struct with the interface types embedded in it.
// For example, to ignore sync.Locker, pass in struct{sync.Locker}{}.
func IgnoreInterfaces(ifaces interface{}) cmp.Option {
tf := newIfaceFilter(ifaces)
return cmp.FilterPath(tf.filter, cmp.Ignore())
}
type ifaceFilter []reflect.Type
func newIfaceFilter(ifaces interface{}) (tf ifaceFilter) {
t := reflect.TypeOf(ifaces)
if ifaces == nil || t.Name() != "" || t.Kind() != reflect.Struct {
panic("input must be an anonymous struct")
}
for i := 0; i < t.NumField(); i++ {
fi := t.Field(i)
switch {
case !fi.Anonymous:
panic("struct cannot have named fields")
case fi.Type.Kind() != reflect.Interface:
panic("embedded field must be an interface type")
case fi.Type.NumMethod() == 0:
// This matches everything; why would you ever want this?
panic("cannot ignore empty interface")
default:
tf = append(tf, fi.Type)
}
}
return tf
}
func (tf ifaceFilter) filter(p cmp.Path) bool {
if len(p) < 1 {
return false
}
t := p[len(p)-1].Type()
for _, ti := range tf {
if t.AssignableTo(ti) {
return true
}
if t.Kind() != reflect.Ptr && reflect.PtrTo(t).AssignableTo(ti) {
return true
}
}
return false
}
// IgnoreUnexported returns an Option that only ignores the immediate unexported
// fields of a struct, including anonymous fields of unexported types.
// In particular, unexported fields within the struct's exported fields
// of struct types, including anonymous fields, will not be ignored unless the
// type of the field itself is also passed to IgnoreUnexported.
func IgnoreUnexported(typs ...interface{}) cmp.Option {
ux := newUnexportedFilter(typs...)
return cmp.FilterPath(ux.filter, cmp.Ignore())
}
type unexportedFilter struct{ m map[reflect.Type]bool }
func newUnexportedFilter(typs ...interface{}) unexportedFilter {
ux := unexportedFilter{m: make(map[reflect.Type]bool)}
for _, typ := range typs {
t := reflect.TypeOf(typ)
if t == nil || t.Kind() != reflect.Struct {
panic(fmt.Sprintf("invalid struct type: %T", typ))
}
ux.m[t] = true
}
return ux
}
func (xf unexportedFilter) filter(p cmp.Path) bool {
if len(p) < 2 {
return false
}
sf, ok := p[len(p)-1].(cmp.StructField)
if !ok {
return false
}
return xf.m[p[len(p)-2].Type()] && !isExported(sf.Name())
}
// isExported reports whether the identifier is exported.
func isExported(id string) bool {
r, _ := utf8.DecodeRuneInString(id)
return unicode.IsUpper(r)
}