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mirror of https://github.com/wader/fq.git synced 2024-12-12 02:22:44 +03:00
fq/format/avro/decoders/record.go
Mattias Wadman e9d9f8aef9 fq: Use go 1.18
Rename s/interface{}/any/g
Preparation for using generics in decode API and native jq funcations etc
Remove some unused linter ignores as linter has been fixed
2022-05-20 15:23:16 +02:00

52 lines
1.5 KiB
Go

package decoders
import (
"fmt"
"github.com/wader/fq/format/avro/schema"
"github.com/wader/fq/pkg/decode"
)
func decodeRecordFn(schema schema.SimplifiedSchema) (DecodeFn, error) {
if len(schema.Fields) == 0 {
return nil, fmt.Errorf("record must have fields")
}
var fieldNames []string
var fieldDecoders []func(string, *decode.D) any
for _, f := range schema.Fields {
fieldNames = append(fieldNames, f.Name)
fc, err := DecodeFnForSchema(f.Type)
if err != nil {
return nil, fmt.Errorf("failed parsing record field %s: %w", f.Name, err)
}
fieldDecoders = append(fieldDecoders, fc)
}
// A record is encoded by encoding the values of its fields in the order that they are declared. In other words, a
// record is encoded as just the concatenation of the encodings of its fields. Field values are encoded per their
// schema. For example, the record schema
// { "type": "record",
// "name": "test",
// "fields" : [
// {"name": "a", "type": "long"},
// {"name": "b", "type": "string"}
// ]
// }
//
// An instance of this record whose a field has value 27 (encoded as hex 36) and whose b field has value "foo"
// (encoded as hex bytes 06 66 6f 6f), would be encoded simply as the concatenation of these, namely
// the hex byte sequence:
// 36 06 66 6f 6f
return func(name string, d *decode.D) any {
val := make(map[string]any)
d.FieldStruct(name, func(d *decode.D) {
for i, f := range fieldNames {
val[f] = fieldDecoders[i](f, d)
}
})
return val
}, nil
}