Scott Baker | e7144bc | 2019-10-01 14:16:47 -0700 | [diff] [blame^] | 1 | package sarama |
| 2 | |
| 3 | import "fmt" |
| 4 | |
| 5 | const ( |
| 6 | unknownRecords = iota |
| 7 | legacyRecords |
| 8 | defaultRecords |
| 9 | |
| 10 | magicOffset = 16 |
| 11 | magicLength = 1 |
| 12 | ) |
| 13 | |
| 14 | // Records implements a union type containing either a RecordBatch or a legacy MessageSet. |
| 15 | type Records struct { |
| 16 | recordsType int |
| 17 | MsgSet *MessageSet |
| 18 | RecordBatch *RecordBatch |
| 19 | } |
| 20 | |
| 21 | func newLegacyRecords(msgSet *MessageSet) Records { |
| 22 | return Records{recordsType: legacyRecords, MsgSet: msgSet} |
| 23 | } |
| 24 | |
| 25 | func newDefaultRecords(batch *RecordBatch) Records { |
| 26 | return Records{recordsType: defaultRecords, RecordBatch: batch} |
| 27 | } |
| 28 | |
| 29 | // setTypeFromFields sets type of Records depending on which of MsgSet or RecordBatch is not nil. |
| 30 | // The first return value indicates whether both fields are nil (and the type is not set). |
| 31 | // If both fields are not nil, it returns an error. |
| 32 | func (r *Records) setTypeFromFields() (bool, error) { |
| 33 | if r.MsgSet == nil && r.RecordBatch == nil { |
| 34 | return true, nil |
| 35 | } |
| 36 | if r.MsgSet != nil && r.RecordBatch != nil { |
| 37 | return false, fmt.Errorf("both MsgSet and RecordBatch are set, but record type is unknown") |
| 38 | } |
| 39 | r.recordsType = defaultRecords |
| 40 | if r.MsgSet != nil { |
| 41 | r.recordsType = legacyRecords |
| 42 | } |
| 43 | return false, nil |
| 44 | } |
| 45 | |
| 46 | func (r *Records) encode(pe packetEncoder) error { |
| 47 | if r.recordsType == unknownRecords { |
| 48 | if empty, err := r.setTypeFromFields(); err != nil || empty { |
| 49 | return err |
| 50 | } |
| 51 | } |
| 52 | |
| 53 | switch r.recordsType { |
| 54 | case legacyRecords: |
| 55 | if r.MsgSet == nil { |
| 56 | return nil |
| 57 | } |
| 58 | return r.MsgSet.encode(pe) |
| 59 | case defaultRecords: |
| 60 | if r.RecordBatch == nil { |
| 61 | return nil |
| 62 | } |
| 63 | return r.RecordBatch.encode(pe) |
| 64 | } |
| 65 | |
| 66 | return fmt.Errorf("unknown records type: %v", r.recordsType) |
| 67 | } |
| 68 | |
| 69 | func (r *Records) setTypeFromMagic(pd packetDecoder) error { |
| 70 | magic, err := magicValue(pd) |
| 71 | if err != nil { |
| 72 | return err |
| 73 | } |
| 74 | |
| 75 | r.recordsType = defaultRecords |
| 76 | if magic < 2 { |
| 77 | r.recordsType = legacyRecords |
| 78 | } |
| 79 | |
| 80 | return nil |
| 81 | } |
| 82 | |
| 83 | func (r *Records) decode(pd packetDecoder) error { |
| 84 | if r.recordsType == unknownRecords { |
| 85 | if err := r.setTypeFromMagic(pd); err != nil { |
| 86 | return err |
| 87 | } |
| 88 | } |
| 89 | |
| 90 | switch r.recordsType { |
| 91 | case legacyRecords: |
| 92 | r.MsgSet = &MessageSet{} |
| 93 | return r.MsgSet.decode(pd) |
| 94 | case defaultRecords: |
| 95 | r.RecordBatch = &RecordBatch{} |
| 96 | return r.RecordBatch.decode(pd) |
| 97 | } |
| 98 | return fmt.Errorf("unknown records type: %v", r.recordsType) |
| 99 | } |
| 100 | |
| 101 | func (r *Records) numRecords() (int, error) { |
| 102 | if r.recordsType == unknownRecords { |
| 103 | if empty, err := r.setTypeFromFields(); err != nil || empty { |
| 104 | return 0, err |
| 105 | } |
| 106 | } |
| 107 | |
| 108 | switch r.recordsType { |
| 109 | case legacyRecords: |
| 110 | if r.MsgSet == nil { |
| 111 | return 0, nil |
| 112 | } |
| 113 | return len(r.MsgSet.Messages), nil |
| 114 | case defaultRecords: |
| 115 | if r.RecordBatch == nil { |
| 116 | return 0, nil |
| 117 | } |
| 118 | return len(r.RecordBatch.Records), nil |
| 119 | } |
| 120 | return 0, fmt.Errorf("unknown records type: %v", r.recordsType) |
| 121 | } |
| 122 | |
| 123 | func (r *Records) isPartial() (bool, error) { |
| 124 | if r.recordsType == unknownRecords { |
| 125 | if empty, err := r.setTypeFromFields(); err != nil || empty { |
| 126 | return false, err |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | switch r.recordsType { |
| 131 | case unknownRecords: |
| 132 | return false, nil |
| 133 | case legacyRecords: |
| 134 | if r.MsgSet == nil { |
| 135 | return false, nil |
| 136 | } |
| 137 | return r.MsgSet.PartialTrailingMessage, nil |
| 138 | case defaultRecords: |
| 139 | if r.RecordBatch == nil { |
| 140 | return false, nil |
| 141 | } |
| 142 | return r.RecordBatch.PartialTrailingRecord, nil |
| 143 | } |
| 144 | return false, fmt.Errorf("unknown records type: %v", r.recordsType) |
| 145 | } |
| 146 | |
| 147 | func (r *Records) isControl() (bool, error) { |
| 148 | if r.recordsType == unknownRecords { |
| 149 | if empty, err := r.setTypeFromFields(); err != nil || empty { |
| 150 | return false, err |
| 151 | } |
| 152 | } |
| 153 | |
| 154 | switch r.recordsType { |
| 155 | case legacyRecords: |
| 156 | return false, nil |
| 157 | case defaultRecords: |
| 158 | if r.RecordBatch == nil { |
| 159 | return false, nil |
| 160 | } |
| 161 | return r.RecordBatch.Control, nil |
| 162 | } |
| 163 | return false, fmt.Errorf("unknown records type: %v", r.recordsType) |
| 164 | } |
| 165 | |
| 166 | func (r *Records) isOverflow() (bool, error) { |
| 167 | if r.recordsType == unknownRecords { |
| 168 | if empty, err := r.setTypeFromFields(); err != nil || empty { |
| 169 | return false, err |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | switch r.recordsType { |
| 174 | case unknownRecords: |
| 175 | return false, nil |
| 176 | case legacyRecords: |
| 177 | if r.MsgSet == nil { |
| 178 | return false, nil |
| 179 | } |
| 180 | return r.MsgSet.OverflowMessage, nil |
| 181 | case defaultRecords: |
| 182 | return false, nil |
| 183 | } |
| 184 | return false, fmt.Errorf("unknown records type: %v", r.recordsType) |
| 185 | } |
| 186 | |
| 187 | func magicValue(pd packetDecoder) (int8, error) { |
| 188 | dec, err := pd.peek(magicOffset, magicLength) |
| 189 | if err != nil { |
| 190 | return 0, err |
| 191 | } |
| 192 | |
| 193 | return dec.getInt8() |
| 194 | } |