forked from mongodb/mongo-tools-common
/
marshal_d.go
66 lines (60 loc) · 1.79 KB
/
marshal_d.go
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// Copyright (C) MongoDB, Inc. 2014-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 bsonutil
import (
"bytes"
"fmt"
"github.com/mongodb/mongo-tools-common/json"
"github.com/mongodb/mongo-tools-common/util"
"go.mongodb.org/mongo-driver/bson"
)
// MarshalD is a wrapper for bson.D that allows unmarshalling
// of bson.D with preserved order. Necessary for printing
// certain database commands.
type MarshalD bson.D
// MarshalJSON makes the MarshalD type usable by
// the encoding/json package.
func (md MarshalD) MarshalJSON() ([]byte, error) {
var buff bytes.Buffer
buff.WriteString("{")
for i, item := range md {
key, err := json.Marshal(item.Key)
if err != nil {
return nil, fmt.Errorf("cannot marshal key %v: %v", item.Key, err)
}
val, err := json.Marshal(item.Value)
if err != nil {
return nil, fmt.Errorf("cannot marshal value %v: %v", item.Value, err)
}
buff.Write(key)
buff.WriteString(":")
buff.Write(val)
if i != len(md)-1 {
buff.WriteString(",")
}
}
buff.WriteString("}")
return buff.Bytes(), nil
}
// MakeSortString takes a bson.D object and converts it to a slice of strings
// that can be used as the input args to mgo's .Sort(...) function.
// For example:
// {a:1, b:-1} -> ["+a", "-b"]
func MakeSortString(sortObj bson.D) ([]string, error) {
sortStrs := make([]string, 0, len(sortObj))
for _, docElem := range sortObj {
valueAsNumber, err := util.ToFloat64(docElem.Value)
if err != nil {
return nil, err
}
prefix := "+"
if valueAsNumber < 0 {
prefix = "-"
}
sortStrs = append(sortStrs, fmt.Sprintf("%v%v", prefix, docElem.Key))
}
return sortStrs, nil
}