66 lines
1.7 KiB
Go
66 lines
1.7 KiB
Go
// Copyright (C) MongoDB, Inc. 2023-present.
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may
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// not use this file except in compliance with the License. You may obtain
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// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
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package codecutil
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import (
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"bytes"
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"errors"
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"fmt"
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"io"
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"reflect"
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"go.mongodb.org/mongo-driver/bson"
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"go.mongodb.org/mongo-driver/x/bsonx/bsoncore"
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)
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var ErrNilValue = errors.New("value is nil")
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// MarshalError is returned when attempting to transform a value into a document
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// results in an error.
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type MarshalError struct {
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Value interface{}
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Err error
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}
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// Error implements the error interface.
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func (e MarshalError) Error() string {
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return fmt.Sprintf("cannot transform type %s to a BSON Document: %v",
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reflect.TypeOf(e.Value), e.Err)
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}
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// EncoderFn is used to functionally construct an encoder for marshaling values.
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type EncoderFn func(io.Writer) (*bson.Encoder, error)
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// MarshalValue will attempt to encode the value with the encoder returned by
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// the encoder function.
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func MarshalValue(val interface{}, encFn EncoderFn) (bsoncore.Value, error) {
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// If the val is already a bsoncore.Value, then do nothing.
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if bval, ok := val.(bsoncore.Value); ok {
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return bval, nil
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}
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if val == nil {
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return bsoncore.Value{}, ErrNilValue
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}
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buf := new(bytes.Buffer)
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enc, err := encFn(buf)
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if err != nil {
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return bsoncore.Value{}, err
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}
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// Encode the value in a single-element document with an empty key. Use
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// bsoncore to extract the first element and return the BSON value.
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err = enc.Encode(bson.D{{Key: "", Value: val}})
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if err != nil {
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return bsoncore.Value{}, MarshalError{Value: val, Err: err}
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}
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return bsoncore.Document(buf.Bytes()).Index(0).Value(), nil
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}
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