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mirror of https://github.com/wader/fq.git synced 2024-12-19 11:21:47 +03:00
fq/format/bson/bson.go
Mattias Wadman 9b81d4d3ab decode: More type safe API and split scalar into multiple types
Preparation to make decoder use less memory and API more type safe.
Now each scalar type has it's own struct type so it can store different
things and enables to have a scalar interface.
Also own types will enable experimenting with decode DLS designs like
using chained methods that are type aware.
2022-12-14 16:23:58 +01:00

121 lines
3.5 KiB
Go

package bson
// https://bsonspec.org/spec.html
// TODO: more types
import (
"embed"
"github.com/wader/fq/format"
"github.com/wader/fq/pkg/decode"
"github.com/wader/fq/pkg/interp"
"github.com/wader/fq/pkg/scalar"
)
//go:embed bson.jq
//go:embed bson.md
var bsonFS embed.FS
func init() {
interp.RegisterFormat(decode.Format{
Name: format.BSON,
Description: "Binary JSON",
DecodeFn: decodeBSON,
Functions: []string{"torepr"},
})
interp.RegisterFS(bsonFS)
}
const (
elementTypeDouble = 0x01
elementTypeString = 0x02
elementTypeDocument = 0x03
elementTypeArray = 0x04
elementTypeBinary = 0x05
elementTypeUndefined = 0x06
elementTypeObjectID = 0x07
elementTypeBoolean = 0x08
elementTypeDatatime = 0x09
elementTypeNull = 0x0a
elementTypeRegexp = 0x0b
elementTypeInt32 = 0x10
elementTypeTimestamp = 0x11
elementTypeInt64 = 0x12
)
var elementTypeMap = scalar.UintMap{
elementTypeDouble: {Sym: "double", Description: "64-bit binary floating point"},
elementTypeString: {Sym: "string", Description: "UTF-8 string"},
elementTypeDocument: {Sym: "document", Description: "Embedded document"},
elementTypeArray: {Sym: "array", Description: "Array"},
elementTypeBinary: {Sym: "binary", Description: "Binary data"},
elementTypeUndefined: {Sym: "undefined", Description: "Undefined (deprecated)"},
elementTypeObjectID: {Sym: "object_id", Description: "ObjectId"},
elementTypeBoolean: {Sym: "boolean", Description: "Boolean"},
elementTypeDatatime: {Sym: "datatime", Description: "UTC datetime"},
elementTypeNull: {Sym: "null", Description: "Null value"},
elementTypeRegexp: {Sym: "regexp", Description: "Regular expression"},
elementTypeInt32: {Sym: "int32", Description: "32-bit integer"},
elementTypeTimestamp: {Sym: "timestamp", Description: "Timestamp"},
elementTypeInt64: {Sym: "int64", Description: "64-bit integer"},
}
func decodeBSONDocument(d *decode.D) {
size := d.FieldU32("size")
d.FramedFn(int64(size-4)*8, func(d *decode.D) {
d.FieldArray("elements", func(d *decode.D) {
for d.BitsLeft() > 8 {
d.FieldStruct("element", func(d *decode.D) {
typ := d.FieldU8("type", elementTypeMap)
d.FieldUTF8Null("name")
switch typ {
case elementTypeDouble:
d.FieldF64("value")
case elementTypeString:
length := d.FieldU32("length")
d.FieldUTF8NullFixedLen("value", int(length))
case elementTypeDocument:
d.FieldStruct("value", decodeBSONDocument)
case elementTypeArray:
d.FieldStruct("value", decodeBSONDocument)
case elementTypeBinary:
length := d.FieldU32("length")
d.FieldU8("subtype")
d.FieldRawLen("value", int64(length)*8)
case elementTypeUndefined:
//deprecated
case elementTypeObjectID:
d.FieldRawLen("value", 12*8)
case elementTypeBoolean:
d.FieldU8("value")
case elementTypeDatatime:
d.FieldS32("value")
case elementTypeNull:
d.FieldValueAny("value", nil)
case elementTypeRegexp:
d.FieldUTF8Null("value")
d.FieldUTF8Null("options")
case elementTypeInt32:
d.FieldS32("value")
case elementTypeTimestamp:
d.FieldU64("value")
case elementTypeInt64:
d.FieldS64("value")
default:
d.FieldRawLen("value", d.BitsLeft())
}
})
}
})
d.FieldU8("terminator", d.UintValidate(0))
})
}
func decodeBSON(d *decode.D, _ any) any {
d.Endian = decode.LittleEndian
decodeBSONDocument(d)
return nil
}