bson/bson_mode.go

83 lines
1.8 KiB
Go

// Copyright (C) MongoDB, Inc. 2017-present.
//
// 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
package bson
import (
"fmt"
)
type mode int
const (
_ mode = iota
mTopLevel
mDocument
mArray
mValue
mElement
mCodeWithScope
mSpacer
)
func (m mode) String() string {
var str string
switch m {
case mTopLevel:
str = "TopLevel"
case mDocument:
str = "Document"
case mArray:
str = "Array"
case mValue:
str = "Value"
case mElement:
str = "Element"
case mCodeWithScope:
str = "CodeWithScope"
case mSpacer:
str = "CodeWithScopeSpacer"
default:
str = "Unknown"
}
return str
}
// TransitionError is an error returned when an invalid progressing a
// ValueReader or ValueWriter state machine occurs.
type TransitionError struct {
name string
parent mode
current mode
destination mode
modes []mode
action string
}
func (te TransitionError) Error() string {
errString := fmt.Sprintf("%s can only %s", te.name, te.action)
if te.destination != mode(0) {
errString = fmt.Sprintf("%s a %s", errString, te.destination)
}
errString = fmt.Sprintf("%s while positioned on a", errString)
for ind, m := range te.modes {
if ind != 0 && len(te.modes) > 2 {
errString = fmt.Sprintf("%s,", errString)
}
if ind == len(te.modes)-1 && len(te.modes) > 1 {
errString = fmt.Sprintf("%s or", errString)
}
errString = fmt.Sprintf("%s %s", errString, m)
}
errString = fmt.Sprintf("%s but is positioned on a %s", errString, te.current)
if te.parent != mode(0) {
errString = fmt.Sprintf("%s with parent %s", errString, te.parent)
}
return errString
}