| // 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 bsoncore |
| |
| import ( |
| "bytes" |
| "errors" |
| "fmt" |
| "io" |
| "strconv" |
| |
| "github.com/go-stack/stack" |
| "github.com/mongodb/mongo-go-driver/bson/bsontype" |
| ) |
| |
| // DocumentValidationError is an error type returned when attempting to validate a document. |
| type DocumentValidationError string |
| |
| func (dve DocumentValidationError) Error() string { return string(dve) } |
| |
| // NewDocumentLengthError creates and returns an error for when the length of a document exceeds the |
| // bytes available. |
| func NewDocumentLengthError(length, rem int) error { |
| return DocumentValidationError( |
| fmt.Sprintf("document length exceeds available bytes. length=%d remainingBytes=%d", length, rem), |
| ) |
| } |
| |
| // InsufficientBytesError indicates that there were not enough bytes to read the next component. |
| type InsufficientBytesError struct { |
| Source []byte |
| Remaining []byte |
| Stack stack.CallStack |
| } |
| |
| // NewInsufficientBytesError creates a new InsufficientBytesError with the given Document, remaining |
| // bytes, and the current stack. |
| func NewInsufficientBytesError(src, rem []byte) InsufficientBytesError { |
| return InsufficientBytesError{Source: src, Remaining: rem, Stack: stack.Trace().TrimRuntime()} |
| } |
| |
| // Error implements the error interface. |
| func (ibe InsufficientBytesError) Error() string { |
| return "too few bytes to read next component" |
| } |
| |
| // ErrorStack returns a string representing the stack at the point where the error occurred. |
| func (ibe InsufficientBytesError) ErrorStack() string { |
| s := bytes.NewBufferString("too few bytes to read next component: [") |
| |
| for i, call := range ibe.Stack { |
| if i != 0 { |
| s.WriteString(", ") |
| } |
| |
| // go vet doesn't like %k even though it's part of stack's API, so we move the format |
| // string so it doesn't complain. (We also can't make it a constant, or go vet still |
| // complains.) |
| callFormat := "%k.%n %v" |
| |
| s.WriteString(fmt.Sprintf(callFormat, call, call, call)) |
| } |
| |
| s.WriteRune(']') |
| |
| return s.String() |
| } |
| |
| // Equal checks that err2 also is an ErrTooSmall. |
| func (ibe InsufficientBytesError) Equal(err2 error) bool { |
| switch err2.(type) { |
| case InsufficientBytesError: |
| return true |
| default: |
| return false |
| } |
| } |
| |
| // InvalidDepthTraversalError is returned when attempting a recursive Lookup when one component of |
| // the path is neither an embedded document nor an array. |
| type InvalidDepthTraversalError struct { |
| Key string |
| Type bsontype.Type |
| } |
| |
| func (idte InvalidDepthTraversalError) Error() string { |
| return fmt.Sprintf( |
| "attempt to traverse into %s, but it's type is %s, not %s nor %s", |
| idte.Key, idte.Type, bsontype.EmbeddedDocument, bsontype.Array, |
| ) |
| } |
| |
| // ErrMissingNull is returned when a document's last byte is not null. |
| const ErrMissingNull DocumentValidationError = "document end is missing null byte" |
| |
| // ErrNilReader indicates that an operation was attempted on a nil io.Reader. |
| var ErrNilReader = errors.New("nil reader") |
| |
| // ErrInvalidLength indicates that a length in a binary representation of a BSON document is invalid. |
| var ErrInvalidLength = errors.New("document length is invalid") |
| |
| // ErrEmptyKey indicates that no key was provided to a Lookup method. |
| var ErrEmptyKey = errors.New("empty key provided") |
| |
| // ErrElementNotFound indicates that an Element matching a certain condition does not exist. |
| var ErrElementNotFound = errors.New("element not found") |
| |
| // ErrOutOfBounds indicates that an index provided to access something was invalid. |
| var ErrOutOfBounds = errors.New("out of bounds") |
| |
| // Document is a raw bytes representation of a BSON document. |
| type Document []byte |
| |
| // NewDocumentFromReader reads a document from r. This function will only validate the length is |
| // correct and that the document ends with a null byte. |
| func NewDocumentFromReader(r io.Reader) (Document, error) { |
| if r == nil { |
| return nil, ErrNilReader |
| } |
| |
| var lengthBytes [4]byte |
| |
| // ReadFull guarantees that we will have read at least len(lengthBytes) if err == nil |
| _, err := io.ReadFull(r, lengthBytes[:]) |
| if err != nil { |
| return nil, err |
| } |
| |
| length, _, _ := readi32(lengthBytes[:]) // ignore ok since we always have enough bytes to read a length |
| if length < 0 { |
| return nil, ErrInvalidLength |
| } |
| document := make([]byte, length) |
| |
| copy(document, lengthBytes[:]) |
| |
| _, err = io.ReadFull(r, document[4:]) |
| if err != nil { |
| return nil, err |
| } |
| |
| if document[length-1] != 0x00 { |
| return nil, ErrMissingNull |
| } |
| |
| return document, nil |
| } |
| |
| // Lookup searches the document, potentially recursively, for the given key. If there are multiple |
| // keys provided, this method will recurse down, as long as the top and intermediate nodes are |
| // either documents or arrays. If an error occurs or if the value doesn't exist, an empty Value is |
| // returned. |
| func (d Document) Lookup(key ...string) Value { |
| val, _ := d.LookupErr(key...) |
| return val |
| } |
| |
| // LookupErr is the same as Lookup, except it returns an error in addition to an empty Value. |
| func (d Document) LookupErr(key ...string) (Value, error) { |
| if len(key) < 1 { |
| return Value{}, ErrEmptyKey |
| } |
| length, rem, ok := ReadLength(d) |
| if !ok { |
| return Value{}, NewInsufficientBytesError(d, rem) |
| } |
| |
| length -= 4 |
| |
| var elem Element |
| for length > 1 { |
| elem, rem, ok = ReadElement(rem) |
| length -= int32(len(elem)) |
| if !ok { |
| return Value{}, NewInsufficientBytesError(d, rem) |
| } |
| if elem.Key() != key[0] { |
| continue |
| } |
| if len(key) > 1 { |
| tt := bsontype.Type(elem[0]) |
| switch tt { |
| case bsontype.EmbeddedDocument: |
| val, err := elem.Value().Document().LookupErr(key[1:]...) |
| if err != nil { |
| return Value{}, err |
| } |
| return val, nil |
| case bsontype.Array: |
| val, err := elem.Value().Array().LookupErr(key[1:]...) |
| if err != nil { |
| return Value{}, err |
| } |
| return val, nil |
| default: |
| return Value{}, InvalidDepthTraversalError{Key: elem.Key(), Type: tt} |
| } |
| } |
| return elem.ValueErr() |
| } |
| return Value{}, ErrElementNotFound |
| } |
| |
| // Index searches for and retrieves the element at the given index. This method will panic if |
| // the document is invalid or if the index is out of bounds. |
| func (d Document) Index(index uint) Element { |
| elem, err := d.IndexErr(index) |
| if err != nil { |
| panic(err) |
| } |
| return elem |
| } |
| |
| // IndexErr searches for and retrieves the element at the given index. |
| func (d Document) IndexErr(index uint) (Element, error) { |
| length, rem, ok := ReadLength(d) |
| if !ok { |
| return nil, NewInsufficientBytesError(d, rem) |
| } |
| |
| length -= 4 |
| |
| var current uint |
| var elem Element |
| for length > 1 { |
| elem, rem, ok = ReadElement(rem) |
| length -= int32(len(elem)) |
| if !ok { |
| return nil, NewInsufficientBytesError(d, rem) |
| } |
| if current != index { |
| current++ |
| continue |
| } |
| return elem, nil |
| } |
| return nil, ErrOutOfBounds |
| } |
| |
| // DebugString outputs a human readable version of Document. It will attempt to stringify the |
| // valid components of the document even if the entire document is not valid. |
| func (d Document) DebugString() string { |
| if len(d) < 5 { |
| return "<malformed>" |
| } |
| var buf bytes.Buffer |
| buf.WriteString("Document") |
| length, rem, _ := ReadLength(d) // We know we have enough bytes to read the length |
| buf.WriteByte('(') |
| buf.WriteString(strconv.Itoa(int(length))) |
| length -= 4 |
| buf.WriteString("){") |
| var elem Element |
| var ok bool |
| for length > 1 { |
| elem, rem, ok = ReadElement(rem) |
| length -= int32(len(elem)) |
| if !ok { |
| buf.WriteString(fmt.Sprintf("<malformed (%d)>", length)) |
| break |
| } |
| fmt.Fprintf(&buf, "%s ", elem.DebugString()) |
| } |
| buf.WriteByte('}') |
| |
| return buf.String() |
| } |
| |
| // String outputs an ExtendedJSON version of Document. If the document is not valid, this method |
| // returns an empty string. |
| func (d Document) String() string { |
| if len(d) < 5 { |
| return "" |
| } |
| var buf bytes.Buffer |
| buf.WriteByte('{') |
| |
| length, rem, _ := ReadLength(d) // We know we have enough bytes to read the length |
| |
| length -= 4 |
| |
| var elem Element |
| var ok bool |
| first := true |
| for length > 1 { |
| if !first { |
| buf.WriteByte(',') |
| } |
| elem, rem, ok = ReadElement(rem) |
| length -= int32(len(elem)) |
| if !ok { |
| return "" |
| } |
| fmt.Fprintf(&buf, "%s", elem.String()) |
| first = false |
| } |
| buf.WriteByte('}') |
| |
| return buf.String() |
| } |
| |
| // Elements returns this document as a slice of elements. The returned slice will contain valid |
| // elements. If the document is not valid, the elements up to the invalid point will be returned |
| // along with an error. |
| func (d Document) Elements() ([]Element, error) { |
| length, rem, ok := ReadLength(d) |
| if !ok { |
| return nil, NewInsufficientBytesError(d, rem) |
| } |
| |
| length -= 4 |
| |
| var elem Element |
| var elems []Element |
| for length > 1 { |
| elem, rem, ok = ReadElement(rem) |
| length -= int32(len(elem)) |
| if !ok { |
| return elems, NewInsufficientBytesError(d, rem) |
| } |
| if err := elem.Validate(); err != nil { |
| return elems, err |
| } |
| elems = append(elems, elem) |
| } |
| return elems, nil |
| } |
| |
| // Values returns this document as a slice of values. The returned slice will contain valid values. |
| // If the document is not valid, the values up to the invalid point will be returned along with an |
| // error. |
| func (d Document) Values() ([]Value, error) { |
| length, rem, ok := ReadLength(d) |
| if !ok { |
| return nil, NewInsufficientBytesError(d, rem) |
| } |
| |
| length -= 4 |
| |
| var elem Element |
| var vals []Value |
| for length > 1 { |
| elem, rem, ok = ReadElement(rem) |
| length -= int32(len(elem)) |
| if !ok { |
| return vals, NewInsufficientBytesError(d, rem) |
| } |
| if err := elem.Value().Validate(); err != nil { |
| return vals, err |
| } |
| vals = append(vals, elem.Value()) |
| } |
| return vals, nil |
| } |
| |
| // Validate validates the document and ensures the elements contained within are valid. |
| func (d Document) Validate() error { |
| length, rem, ok := ReadLength(d) |
| if !ok { |
| return NewInsufficientBytesError(d, rem) |
| } |
| if int(length) > len(d) { |
| return d.lengtherror(int(length), len(d)) |
| } |
| if d[length-1] != 0x00 { |
| return ErrMissingNull |
| } |
| |
| length -= 4 |
| var elem Element |
| |
| for length > 1 { |
| elem, rem, ok = ReadElement(rem) |
| length -= int32(len(elem)) |
| if !ok { |
| return NewInsufficientBytesError(d, rem) |
| } |
| err := elem.Validate() |
| if err != nil { |
| return err |
| } |
| } |
| |
| if len(rem) < 1 || rem[0] != 0x00 { |
| return ErrMissingNull |
| } |
| return nil |
| } |
| |
| func (Document) lengtherror(length, rem int) error { |
| return DocumentValidationError(fmt.Sprintf("document length exceeds available bytes. length=%d remainingBytes=%d", length, rem)) |
| } |