95 lines
2.2 KiB
Go
95 lines
2.2 KiB
Go
// Copyright 2016 Google Inc. All Rights Reserved.
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//
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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// Package optional provides versions of primitive types that can
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// be nil. These are useful in methods that update some of an API object's
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// fields.
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package optional
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import (
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"fmt"
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"strings"
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)
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type (
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// Bool is either a bool or nil.
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Bool interface{}
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// String is either a string or nil.
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String interface{}
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// Int is either an int or nil.
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Int interface{}
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// Uint is either a uint or nil.
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Uint interface{}
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// Float64 is either a float64 or nil.
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Float64 interface{}
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)
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// ToBool returns its argument as a bool.
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// It panics if its argument is nil or not a bool.
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func ToBool(v Bool) bool {
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x, ok := v.(bool)
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if !ok {
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doPanic("Bool", v)
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}
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return x
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}
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// ToString returns its argument as a string.
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// It panics if its argument is nil or not a string.
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func ToString(v String) string {
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x, ok := v.(string)
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if !ok {
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doPanic("String", v)
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}
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return x
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}
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// ToInt returns its argument as an int.
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// It panics if its argument is nil or not an int.
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func ToInt(v Int) int {
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x, ok := v.(int)
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if !ok {
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doPanic("Int", v)
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}
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return x
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}
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// ToUint returns its argument as a uint.
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// It panics if its argument is nil or not a uint.
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func ToUint(v Uint) uint {
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x, ok := v.(uint)
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if !ok {
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doPanic("Uint", v)
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}
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return x
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}
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// ToFloat64 returns its argument as a float64.
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// It panics if its argument is nil or not a float64.
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func ToFloat64(v Float64) float64 {
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x, ok := v.(float64)
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if !ok {
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doPanic("Float64", v)
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}
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return x
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}
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func doPanic(capType string, v interface{}) {
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panic(fmt.Sprintf("optional.%s value should be %s, got %T", capType, strings.ToLower(capType), v))
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}
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