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// Copyright (C) MongoDB, Inc. 2017-present.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License. You may obtain
// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
package bsonx
import (
"bytes"
"errors"
"fmt"
"go.mongodb.org/mongo-driver/bson/bsontype"
"go.mongodb.org/mongo-driver/x/bsonx/bsoncore"
)
// ErrNilDocument indicates that an operation was attempted on a nil *bson.Document.
var ErrNilDocument = errors.New("document is nil")
// KeyNotFound is an error type returned from the Lookup methods on Document. This type contains
// information about which key was not found and if it was actually not found or if a component of
// the key except the last was not a document nor array.
type KeyNotFound struct {
Key []string // The keys that were searched for.
Depth uint // Which key either was not found or was an incorrect type.
Type bsontype.Type // The type of the key that was found but was an incorrect type.
}
func (knf KeyNotFound) Error() string {
depth := knf.Depth
if depth >= uint(len(knf.Key)) {
depth = uint(len(knf.Key)) - 1
}
if len(knf.Key) == 0 {
return "no keys were provided for lookup"
}
if knf.Type != bsontype.Type(0) {
return fmt.Sprintf(`key "%s" was found but was not valid to traverse BSON type %s`, knf.Key[depth], knf.Type)
}
return fmt.Sprintf(`key "%s" was not found`, knf.Key[depth])
}
// Doc is a type safe, concise BSON document representation.
type Doc []Elem
// ReadDoc will create a Document using the provided slice of bytes. If the
// slice of bytes is not a valid BSON document, this method will return an error.
func ReadDoc(b []byte) (Doc, error) {
doc := make(Doc, 0)
err := doc.UnmarshalBSON(b)
if err != nil {
return nil, err
}
return doc, nil
}
// Copy makes a shallow copy of this document.
func (d Doc) Copy() Doc {
d2 := make(Doc, len(d))
copy(d2, d)
return d2
}
// Append adds an element to the end of the document, creating it from the key and value provided.
func (d Doc) Append(key string, val Val) Doc {
return append(d, Elem{Key: key, Value: val})
}
// Prepend adds an element to the beginning of the document, creating it from the key and value provided.
func (d Doc) Prepend(key string, val Val) Doc {
// TODO: should we just modify d itself instead of doing an alloc here?
return append(Doc{{Key: key, Value: val}}, d...)
}
// Set replaces an element of a document. If an element with a matching key is
// found, the element will be replaced with the one provided. If the document
// does not have an element with that key, the element is appended to the
// document instead.
func (d Doc) Set(key string, val Val) Doc {
idx := d.IndexOf(key)
if idx == -1 {
return append(d, Elem{Key: key, Value: val})
}
d[idx] = Elem{Key: key, Value: val}
return d
}
// IndexOf returns the index of the first element with a key of key, or -1 if no element with a key
// was found.
func (d Doc) IndexOf(key string) int {
for i, e := range d {
if e.Key == key {
return i
}
}
return -1
}
// Delete removes the element with key if it exists and returns the updated Doc.
func (d Doc) Delete(key string) Doc {
idx := d.IndexOf(key)
if idx == -1 {
return d
}
return append(d[:idx], d[idx+1:]...)
}
// Lookup searches the document and potentially subdocuments or arrays for the
// provided key. Each key provided to this method represents a layer of depth.
//
// This method will return an empty Value if they key does not exist. To know if they key actually
// exists, use LookupErr.
func (d Doc) Lookup(key ...string) Val {
val, _ := d.LookupErr(key...)
return val
}
// LookupErr searches the document and potentially subdocuments or arrays for the
// provided key. Each key provided to this method represents a layer of depth.
func (d Doc) LookupErr(key ...string) (Val, error) {
elem, err := d.LookupElementErr(key...)
return elem.Value, err
}
// LookupElement searches the document and potentially subdocuments or arrays for the
// provided key. Each key provided to this method represents a layer of depth.
//
// This method will return an empty Element if they key does not exist. To know if they key actually
// exists, use LookupElementErr.
func (d Doc) LookupElement(key ...string) Elem {
elem, _ := d.LookupElementErr(key...)
return elem
}
// LookupElementErr searches the document and potentially subdocuments for the
// provided key. Each key provided to this method represents a layer of depth.
func (d Doc) LookupElementErr(key ...string) (Elem, error) {
// KeyNotFound operates by being created where the error happens and then the depth is
// incremented by 1 as each function unwinds. Whenever this function returns, it also assigns
// the Key slice to the key slice it has. This ensures that the proper depth is identified and
// the proper keys.
if len(key) == 0 {
return Elem{}, KeyNotFound{Key: key}
}
var elem Elem
var err error
idx := d.IndexOf(key[0])
if idx == -1 {
return Elem{}, KeyNotFound{Key: key}
}
elem = d[idx]
if len(key) == 1 {
return elem, nil
}
switch elem.Value.Type() {
case bsontype.EmbeddedDocument:
switch tt := elem.Value.primitive.(type) {
case Doc:
elem, err = tt.LookupElementErr(key[1:]...)
case MDoc:
elem, err = tt.LookupElementErr(key[1:]...)
}
default:
return Elem{}, KeyNotFound{Type: elem.Value.Type()}
}
switch tt := err.(type) {
case KeyNotFound:
tt.Depth++
tt.Key = key
return Elem{}, tt
case nil:
return elem, nil
default:
return Elem{}, err // We can't actually hit this.
}
}
// MarshalBSONValue implements the bsoncodec.ValueMarshaler interface.
//
// This method will never return an error.
func (d Doc) MarshalBSONValue() (bsontype.Type, []byte, error) {
if d == nil {
// TODO: Should we do this?
return bsontype.Null, nil, nil
}
data, _ := d.MarshalBSON()
return bsontype.EmbeddedDocument, data, nil
}
// MarshalBSON implements the Marshaler interface.
//
// This method will never return an error.
func (d Doc) MarshalBSON() ([]byte, error) { return d.AppendMarshalBSON(nil) }
// AppendMarshalBSON marshals Doc to BSON bytes, appending to dst.
//
// This method will never return an error.
func (d Doc) AppendMarshalBSON(dst []byte) ([]byte, error) {
idx, dst := bsoncore.ReserveLength(dst)
for _, elem := range d {
t, data, _ := elem.Value.MarshalBSONValue() // Value.MarshalBSONValue never returns an error.
dst = append(dst, byte(t))
dst = append(dst, elem.Key...)
dst = append(dst, 0x00)
dst = append(dst, data...)
}
dst = append(dst, 0x00)
dst = bsoncore.UpdateLength(dst, idx, int32(len(dst[idx:])))
return dst, nil
}
// UnmarshalBSON implements the Unmarshaler interface.
func (d *Doc) UnmarshalBSON(b []byte) error {
if d == nil {
return ErrNilDocument
}
if err := bsoncore.Document(b).Validate(); err != nil {
return err
}
elems, err := bsoncore.Document(b).Elements()
if err != nil {
return err
}
var val Val
for _, elem := range elems {
rawv := elem.Value()
err = val.UnmarshalBSONValue(rawv.Type, rawv.Data)
if err != nil {
return err
}
*d = d.Append(elem.Key(), val)
}
return nil
}
// UnmarshalBSONValue implements the bson.ValueUnmarshaler interface.
func (d *Doc) UnmarshalBSONValue(t bsontype.Type, data []byte) error {
if t != bsontype.EmbeddedDocument {
return fmt.Errorf("cannot unmarshal %s into a bsonx.Doc", t)
}
return d.UnmarshalBSON(data)
}
// Equal compares this document to another, returning true if they are equal.
func (d Doc) Equal(id IDoc) bool {
switch tt := id.(type) {
case Doc:
d2 := tt
if len(d) != len(d2) {
return false
}
for idx := range d {
if !d[idx].Equal(d2[idx]) {
return false
}
}
case MDoc:
unique := make(map[string]struct{}, 0)
for _, elem := range d {
unique[elem.Key] = struct{}{}
val, ok := tt[elem.Key]
if !ok {
return false
}
if !val.Equal(elem.Value) {
return false
}
}
if len(unique) != len(tt) {
return false
}
case nil:
return d == nil
default:
return false
}
return true
}
// String implements the fmt.Stringer interface.
func (d Doc) String() string {
var buf bytes.Buffer
buf.Write([]byte("bson.Document{"))
for idx, elem := range d {
if idx > 0 {
buf.Write([]byte(", "))
}
fmt.Fprintf(&buf, "%v", elem)
}
buf.WriteByte('}')
return buf.String()
}
func (Doc) idoc() {}
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