mode.go

Documentation: go.mongodb.org/mongo-driver/bson/bsoncodec

     1  // Copyright (C) MongoDB, Inc. 2017-present.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License"); you may
     4  // not use this file except in compliance with the License. You may obtain
     5  // a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
     6  
     7  package bsoncodec
     8  
     9  import "fmt"
    10  
    11  type mode int
    12  
    13  const (
    14  	_ mode = iota
    15  	mTopLevel
    16  	mDocument
    17  	mArray
    18  	mValue
    19  	mElement
    20  	mCodeWithScope
    21  	mSpacer
    22  )
    23  
    24  func (m mode) String() string {
    25  	var str string
    26  
    27  	switch m {
    28  	case mTopLevel:
    29  		str = "TopLevel"
    30  	case mDocument:
    31  		str = "DocumentMode"
    32  	case mArray:
    33  		str = "ArrayMode"
    34  	case mValue:
    35  		str = "ValueMode"
    36  	case mElement:
    37  		str = "ElementMode"
    38  	case mCodeWithScope:
    39  		str = "CodeWithScopeMode"
    40  	case mSpacer:
    41  		str = "CodeWithScopeSpacerFrame"
    42  	default:
    43  		str = "UnknownMode"
    44  	}
    45  
    46  	return str
    47  }
    48  
    49  // TransitionError is an error returned when an invalid progressing a
    50  // ValueReader or ValueWriter state machine occurs.
    51  type TransitionError struct {
    52  	parent      mode
    53  	current     mode
    54  	destination mode
    55  }
    56  
    57  func (te TransitionError) Error() string {
    58  	if te.destination == mode(0) {
    59  		return fmt.Sprintf("invalid state transition: cannot read/write value while in %s", te.current)
    60  	}
    61  	if te.parent == mode(0) {
    62  		return fmt.Sprintf("invalid state transition: %s -> %s", te.current, te.destination)
    63  	}
    64  	return fmt.Sprintf("invalid state transition: %s -> %s; parent %s", te.current, te.destination, te.parent)
    65  }
    66
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