mirror of https://github.com/knative/pkg.git
75 lines
2.4 KiB
Go
75 lines
2.4 KiB
Go
/*
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Copyright 2018 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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https://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 configmap
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import (
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"errors"
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"reflect"
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corev1 "k8s.io/api/core/v1"
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)
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// TypeFilter accepts instances of types to check against and returns a function transformer that would only let
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// the call to f through if value is assignable to any one of types of ts. Example:
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//
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// F := configmap.TypeFilter(&config.Domain{})(f)
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//
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// The result is a function F(name string, value interface{}) that will call the underlying function
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// f(name, value) iff value is a *config.Domain
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func TypeFilter(ts ...interface{}) func(func(string, interface{})) func(string, interface{}) {
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return func(f func(string, interface{})) func(string, interface{}) {
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return func(name string, value interface{}) {
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satisfies := false
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for _, t := range ts {
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t := reflect.TypeOf(t)
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if reflect.TypeOf(value).AssignableTo(t) {
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satisfies = true
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break
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}
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}
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if satisfies {
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f(name, value)
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}
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}
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}
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}
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// ValidateConstructor checks the type of the constructor it evaluates
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// the constructor to be a function with correct signature.
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//
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// The expectation is for the constructor to receive a single input
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// parameter of type corev1.ConfigMap as the input and return two
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// values with the second value being of type error
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func ValidateConstructor(constructor interface{}) error {
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cType := reflect.TypeOf(constructor)
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if cType.Kind() != reflect.Func {
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return errors.New("config constructor must be a function")
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}
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if cType.NumIn() != 1 || cType.In(0) != reflect.TypeOf(&corev1.ConfigMap{}) {
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return errors.New("config constructor must be of the type func(*k8s.io/api/core/v1/ConfigMap) (..., error)")
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}
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errorType := reflect.TypeOf((*error)(nil)).Elem()
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if cType.NumOut() != 2 || !cType.Out(1).Implements(errorType) {
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return errors.New("config constructor must be of the type func(*k8s.io/api/core/v1/ConfigMap) (..., error)")
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}
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return nil
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}
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