Add PropertyIndexesWithTag

Add a function that returns all of the indexes to properties in
a property struct that are tagged with `name:"value"`.

Test: proptools/tag_test.go
Change-Id: I00294934c1a0383c8b64ecaabc0e138682efb2e5
This commit is contained in:
Colin Cross 2019-03-05 16:34:45 -08:00
parent 17a0b96440
commit a4f6a3bebf
4 changed files with 209 additions and 13 deletions

View file

@ -80,12 +80,14 @@ bootstrap_go_package {
"proptools/escape.go",
"proptools/extend.go",
"proptools/proptools.go",
"proptools/tag.go",
"proptools/typeequal.go",
],
testSrcs: [
"proptools/clone_test.go",
"proptools/escape_test.go",
"proptools/extend_test.go",
"proptools/tag_test.go",
"proptools/typeequal_test.go",
],
}

View file

@ -15,8 +15,6 @@
package proptools
import (
"reflect"
"strings"
"unicode"
"unicode/utf8"
)
@ -39,17 +37,6 @@ func FieldNameForProperty(propertyName string) string {
return fieldName
}
func HasTag(field reflect.StructField, name, value string) bool {
tag := field.Tag.Get(name)
for _, entry := range strings.Split(tag, ",") {
if entry == value {
return true
}
}
return false
}
// BoolPtr returns a pointer to a new bool containing the given value.
func BoolPtr(b bool) *bool {
return &b

67
proptools/tag.go Normal file
View file

@ -0,0 +1,67 @@
// Copyright 2019 Google Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package proptools
import (
"fmt"
"reflect"
"strings"
)
// HasTag returns true if a StructField has a tag in the form `name:"foo,value"`.
func HasTag(field reflect.StructField, name, value string) bool {
tag := field.Tag.Get(name)
for _, entry := range strings.Split(tag, ",") {
if entry == value {
return true
}
}
return false
}
// PropertyIndexesWithTag returns the indexes of all properties (in the form used by reflect.Value.FieldByIndex) that
// are tagged with the given key and value, including ones found in embedded structs or pointers to structs.
func PropertyIndexesWithTag(ps interface{}, key, value string) [][]int {
t := reflect.TypeOf(ps)
if t.Kind() != reflect.Ptr || t.Elem().Kind() != reflect.Struct {
panic(fmt.Errorf("type %s is not a pointer to a struct", t))
}
t = t.Elem()
return propertyIndexesWithTag(t, key, value)
}
func propertyIndexesWithTag(t reflect.Type, key, value string) [][]int {
var indexes [][]int
for i := 0; i < t.NumField(); i++ {
field := t.Field(i)
ft := field.Type
if ft.Kind() == reflect.Struct || (ft.Kind() == reflect.Ptr && ft.Elem().Kind() == reflect.Struct) {
if ft.Kind() == reflect.Ptr {
ft = ft.Elem()
}
subIndexes := propertyIndexesWithTag(ft, key, value)
for _, sub := range subIndexes {
sub = append([]int{i}, sub...)
indexes = append(indexes, sub)
}
} else if HasTag(field, key, value) {
indexes = append(indexes, field.Index)
}
}
return indexes
}

140
proptools/tag_test.go Normal file
View file

@ -0,0 +1,140 @@
// Copyright 2019 Google Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package proptools
import (
"reflect"
"testing"
)
func TestHasTag(t *testing.T) {
type testType struct {
NoTag string
EmptyTag string ``
OtherTag string `foo:"bar"`
MatchingTag string `name:"value"`
ExtraValues string `name:"foo,value,bar"`
ExtraTags string `foo:"bar" name:"value"`
}
tests := []struct {
field string
want bool
}{
{
field: "NoTag",
want: false,
},
{
field: "EmptyTag",
want: false,
},
{
field: "OtherTag",
want: false,
},
{
field: "MatchingTag",
want: true,
},
{
field: "ExtraValues",
want: true,
},
{
field: "ExtraTags",
want: true,
},
}
for _, test := range tests {
t.Run(test.field, func(t *testing.T) {
field, _ := reflect.TypeOf(testType{}).FieldByName(test.field)
if got := HasTag(field, "name", "value"); got != test.want {
t.Errorf(`HasTag(%q, "name", "value") = %v, want %v`, field.Tag, got, test.want)
}
})
}
}
func TestPropertyIndexesWithTag(t *testing.T) {
tests := []struct {
name string
ps interface{}
want [][]int
}{
{
name: "none",
ps: &struct {
Foo string
}{},
want: nil,
},
{
name: "one",
ps: &struct {
Foo string `name:"value"`
}{},
want: [][]int{{0}},
},
{
name: "two",
ps: &struct {
Foo string `name:"value"`
Bar string `name:"value"`
}{},
want: [][]int{{0}, {1}},
},
{
name: "some",
ps: &struct {
Foo string `name:"other"`
Bar string `name:"value"`
}{},
want: [][]int{{1}},
},
{
name: "embedded",
ps: &struct {
Foo struct {
Bar string `name:"value"`
}
}{},
want: [][]int{{0, 0}},
},
{
name: "embedded ptr",
ps: &struct {
Foo *struct {
Bar string `name:"value"`
}
}{},
want: [][]int{{0, 0}},
},
{
name: "nil",
ps: (*struct {
Foo string `name:"value"`
})(nil),
want: [][]int{{0}},
},
}
for _, test := range tests {
t.Run(test.name, func(t *testing.T) {
if got := PropertyIndexesWithTag(test.ps, "name", "value"); !reflect.DeepEqual(got, test.want) {
t.Errorf("PropertyIndexesWithTag() = %v, want %v", got, test.want)
}
})
}
}