mirror of https://github.com/k3s-io/k3s
147 lines
3.7 KiB
Go
147 lines
3.7 KiB
Go
//+build !prod
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//
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// Copyright (c) 2014 The godbc Authors
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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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// Design-by-Contract for Go
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//
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// Design by Contract is a programming methodology
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// which binds the caller and the function called to a
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// contract. The contract is represented using Hoare Triple:
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// {P} C {Q}
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// where {P} is the precondition before executing command C,
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// and {Q} is the postcondition.
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//
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// See Also
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//
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// * http://en.wikipedia.org/wiki/Design_by_contract
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// * http://en.wikipedia.org/wiki/Hoare_logic
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// * http://dlang.org/dbc.html
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//
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// Usage
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//
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// Godbc is enabled by default, but can be disabled for production
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// builds by using the tag 'prod' in builds and tests as follows:
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// go build -tags 'prod'
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// or
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// go test -tags 'prod'
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//
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package godbc
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import (
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"errors"
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"fmt"
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"runtime"
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)
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// InvariantSimpleTester is an interface which provides a receiver to
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// test the object
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type InvariantSimpleTester interface {
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Invariant() bool
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}
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// InvariantTester is an interface which provides not only an Invariant(),
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// but also a receiver to print the structure
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type InvariantTester interface {
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InvariantSimpleTester
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String() string
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}
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// dbc_panic prints to the screen information of the failure followed
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// by a call to panic()
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func dbc_panic(dbc_func_name string, b bool, message ...interface{}) {
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if !b {
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// Get caller information which is the caller
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// of the caller of this function
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pc, file, line, _ := runtime.Caller(2)
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caller_func_info := runtime.FuncForPC(pc)
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error_string := fmt.Sprintf("%s:\n\r\tfunc (%s) 0x%x\n\r\tFile %s:%d",
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dbc_func_name,
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caller_func_info.Name(),
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pc,
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file,
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line)
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if len(message) > 0 {
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error_string += fmt.Sprintf("\n\r\tInfo: %+v", message)
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}
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err := errors.New(error_string)
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// Finally panic
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panic(err)
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}
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}
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// Require checks that the preconditions are satisfied before
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// executing the function
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//
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// Example Code
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//
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// func Divide(a, b int) int {
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// godbc.Require(b != 0)
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// return a/b
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// }
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//
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func Require(b bool, message ...interface{}) {
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dbc_panic("REQUIRE", b, message...)
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}
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// Ensure checks the postconditions are satisfied before returning
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// to the caller.
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//
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// Example Code
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//
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// type Data struct {
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// a int
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// }
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//
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// func (*d Data) Set(a int) {
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// d.a = a
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// godbc.Ensure(d.a == a)
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// }
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//
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func Ensure(b bool, message ...interface{}) {
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dbc_panic("ENSURE", b, message...)
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}
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// Check provides a simple assert
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func Check(b bool, message ...interface{}) {
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dbc_panic("CHECK", b, message...)
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}
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// InvariantSimple calls the objects Invariant() receiver to test
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// the object for correctness.
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//
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// The caller object must provide an object that supports the
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// interface InvariantSimpleTester and does not need to provide
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// a String() receiver
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func InvariantSimple(obj InvariantSimpleTester, message ...interface{}) {
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dbc_panic("INVARIANT", obj.Invariant(), message...)
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}
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// Invariant calls the objects Invariant() receiver to test
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// the object for correctness.
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//
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// The caller object must provide an object that supports the
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// interface InvariantTester
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//
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// To see an example, please take a look at the godbc_test.go
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func Invariant(obj InvariantTester, message ...interface{}) {
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m := append(message, obj)
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dbc_panic("INVARIANT", obj.Invariant(), m)
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}
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