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// Based on gopkg.in/mgo.v2/bson by Gustavo Niemeyer 8// See THIRD-PARTY-NOTICES for original license terms. 9 10package primitive 11 12import ( 13 "bytes" 14 "crypto/rand" 15 "encoding/binary" 16 "encoding/hex" 17 "encoding/json" 18 "errors" 19 "fmt" 20 "io" 21 "sync/atomic" 22 "time" 23) 24 25// ErrInvalidHex indicates that a hex string cannot be converted to an ObjectID. 26var ErrInvalidHex = errors.New("the provided hex string is not a valid ObjectID") 27 28// ObjectID is the BSON ObjectID type. 29type ObjectID [12]byte 30 31// NilObjectID is the zero value for ObjectID. 32var NilObjectID ObjectID 33 34var objectIDCounter = readRandomUint32() 35var processUnique = processUniqueBytes() 36 37// NewObjectID generates a new ObjectID. 38func NewObjectID() ObjectID { 39 return NewObjectIDFromTimestamp(time.Now()) 40} 41 42// NewObjectIDFromTimestamp generates a new ObjectID based on the given time. 43func NewObjectIDFromTimestamp(timestamp time.Time) ObjectID { 44 var b [12]byte 45 46 binary.BigEndian.PutUint32(b[0:4], uint32(timestamp.Unix())) 47 copy(b[4:9], processUnique[:]) 48 putUint24(b[9:12], atomic.AddUint32(&objectIDCounter, 1)) 49 50 return b 51} 52 53// Timestamp extracts the time part of the ObjectId. 54func (id ObjectID) Timestamp() time.Time { 55 unixSecs := binary.BigEndian.Uint32(id[0:4]) 56 return time.Unix(int64(unixSecs), 0).UTC() 57} 58 59// Hex returns the hex encoding of the ObjectID as a string. 60func (id ObjectID) Hex() string { 61 return hex.EncodeToString(id[:]) 62} 63 64func (id ObjectID) String() string { 65 return fmt.Sprintf("ObjectID(%q)", id.Hex()) 66} 67 68// IsZero returns true if id is the empty ObjectID. 69func (id ObjectID) IsZero() bool { 70 return bytes.Equal(id[:], NilObjectID[:]) 71} 72 73// ObjectIDFromHex creates a new ObjectID from a hex string. It returns an error if the hex string is not a 74// valid ObjectID. 75func ObjectIDFromHex(s string) (ObjectID, error) { 76 b, err := hex.DecodeString(s) 77 if err != nil { 78 return NilObjectID, err 79 } 80 81 if len(b) != 12 { 82 return NilObjectID, ErrInvalidHex 83 } 84 85 var oid [12]byte 86 copy(oid[:], b[:]) 87 88 return oid, nil 89} 90 91// MarshalJSON returns the ObjectID as a string 92func (id ObjectID) MarshalJSON() ([]byte, error) { 93 return json.Marshal(id.Hex()) 94} 95 96// UnmarshalJSON populates the byte slice with the ObjectID. If the byte slice is 64 bytes long, it 97// will be populated with the hex representation of the ObjectID. If the byte slice is twelve bytes 98// long, it will be populated with the BSON representation of the ObjectID. Otherwise, it will 99// return an error. 100func (id *ObjectID) UnmarshalJSON(b []byte) error { 101 var err error 102 switch len(b) { 103 case 12: 104 copy(id[:], b) 105 default: 106 // Extended JSON 107 var res interface{} 108 err := json.Unmarshal(b, &res) 109 if err != nil { 110 return err 111 } 112 str, ok := res.(string) 113 if !ok { 114 m, ok := res.(map[string]interface{}) 115 if !ok { 116 return errors.New("not an extended JSON ObjectID") 117 } 118 oid, ok := m["$oid"] 119 if !ok { 120 return errors.New("not an extended JSON ObjectID") 121 } 122 str, ok = oid.(string) 123 if !ok { 124 return errors.New("not an extended JSON ObjectID") 125 } 126 } 127 128 if len(str) != 24 { 129 return fmt.Errorf("cannot unmarshal into an ObjectID, the length must be 12 but it is %d", len(str)) 130 } 131 132 _, err = hex.Decode(id[:], []byte(str)) 133 if err != nil { 134 return err 135 } 136 } 137 138 return err 139} 140 141func processUniqueBytes() [5]byte { 142 var b [5]byte 143 _, err := io.ReadFull(rand.Reader, b[:]) 144 if err != nil { 145 panic(fmt.Errorf("cannot initialize objectid package with crypto.rand.Reader: %v", err)) 146 } 147 148 return b 149} 150 151func readRandomUint32() uint32 { 152 var b [4]byte 153 _, err := io.ReadFull(rand.Reader, b[:]) 154 if err != nil { 155 panic(fmt.Errorf("cannot initialize objectid package with crypto.rand.Reader: %v", err)) 156 } 157 158 return (uint32(b[0]) << 0) | (uint32(b[1]) << 8) | (uint32(b[2]) << 16) | (uint32(b[3]) << 24) 159} 160 161func putUint24(b []byte, v uint32) { 162 b[0] = byte(v >> 16) 163 b[1] = byte(v >> 8) 164 b[2] = byte(v) 165} 166