mirror of https://github.com/knative/pkg.git
146 lines
3.9 KiB
Go
146 lines
3.9 KiB
Go
/*
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Copyright 2019 The Knative Authors
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package kmp
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import (
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"fmt"
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"reflect"
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"sort"
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"strings"
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"github.com/google/go-cmp/cmp"
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)
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// fieldListReporter implements the cmp.Reporter interface. It keeps
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// track of the field names that differ between two structs and reports
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// them through the Fields() function.
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type fieldListReporter struct {
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path cmp.Path
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fieldNames []string
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}
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// PushStep implements the cmp.Reporter.
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func (r *fieldListReporter) PushStep(ps cmp.PathStep) {
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r.path = append(r.path, ps)
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}
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// fieldName returns a readable name for the field. If the field has JSON annotations it
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// returns the JSON key. If the field does not have JSON annotations or the JSON annotation
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// marks the field as ignored it returns the field's go name
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func (r *fieldListReporter) fieldName() string {
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if len(r.path) < 2 {
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return r.path.Index(0).String()
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}
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fieldName := strings.TrimPrefix(r.path.Index(1).String(), ".")
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// Prefer JSON name to fieldName if it exists
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structField, exists := r.path.Index(0).Type().FieldByName(fieldName)
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if exists {
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tag := structField.Tag.Get("json")
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if tag != "" && tag != "-" {
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return strings.SplitN(tag, ",", 2)[0]
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}
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}
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return fieldName
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}
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// Report implements the cmp.Reporter.
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func (r *fieldListReporter) Report(rs cmp.Result) {
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if rs.Equal() {
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return
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}
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name := r.fieldName()
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// Only append elements we don't already have.
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for _, v := range r.fieldNames {
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if name == v {
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return
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}
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}
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r.fieldNames = append(r.fieldNames, name)
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}
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// PopStep implements cmp.Reporter.
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func (r *fieldListReporter) PopStep() {
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r.path = r.path[:len(r.path)-1]
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}
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// Fields returns the field names that differed between the two
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// objects after calling cmp.Equal with the FieldListReporter. Field names
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// are returned in alphabetical order.
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func (r *fieldListReporter) Fields() []string {
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sort.Strings(r.fieldNames)
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return r.fieldNames
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}
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// shortDiffReporter implements the cmp.Reporter interface. It reports
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// on fields which have diffing values in a short zero-context, unified diff
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// format.
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type shortDiffReporter struct {
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path cmp.Path
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diffs []string
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err error
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}
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// PushStep implements the cmp.Reporter.
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func (r *shortDiffReporter) PushStep(ps cmp.PathStep) {
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r.path = append(r.path, ps)
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}
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// Report implements the cmp.Reporter.
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func (r *shortDiffReporter) Report(rs cmp.Result) {
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if rs.Equal() {
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return
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}
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cur := r.path.Last()
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vx, vy := cur.Values()
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t := cur.Type()
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// Prefix struct values with the types to add clarity in output
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if !vx.IsValid() && !vy.IsValid() {
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r.err = fmt.Errorf("unable to diff %+v and %+v on path %#v", vx, vy, r.path)
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return
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}
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diff := fmt.Sprintf("%#v:\n", r.path)
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if vx.IsValid() {
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diff += r.diffString("-", t, vx)
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}
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if vy.IsValid() {
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diff += r.diffString("+", t, vy)
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}
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r.diffs = append(r.diffs, diff)
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}
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func (r *shortDiffReporter) diffString(diffType string, t reflect.Type, v reflect.Value) string {
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if t.Kind() == reflect.Struct {
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return fmt.Sprintf("\t%s: %+v: \"%+v\"\n", diffType, t, v)
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}
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return fmt.Sprintf("\t%s: \"%+v\"\n", diffType, v)
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}
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// PopStep implements the cmp.Reporter.
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func (r *shortDiffReporter) PopStep() {
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r.path = r.path[:len(r.path)-1]
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}
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// Diff returns the generated short diff for this object.
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// cmp.Equal should be called before this method.
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func (r *shortDiffReporter) Diff() (string, error) {
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if r.err != nil {
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return "", r.err
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}
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return strings.Join(r.diffs, ""), nil
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}
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