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IM/MDB/imm_mongodb/bsoncxx/document/element.hpp
2023-05-29 18:12:22 +08:00

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// Copyright 2014 MongoDB Inc.
//
// 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
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#pragma once
#include <cstddef>
#include <cstdint>
#include <bsoncxx/stdx/string_view.hpp>
#include <bsoncxx/config/prelude.hpp>
namespace bsoncxx {
BSONCXX_INLINE_NAMESPACE_BEGIN
enum class type : std::uint8_t;
enum class binary_sub_type : std::uint8_t;
namespace types {
struct b_eod;
struct b_double;
struct b_string;
struct b_document;
struct b_array;
struct b_binary;
struct b_undefined;
struct b_oid;
struct b_bool;
struct b_date;
struct b_null;
struct b_regex;
struct b_dbpointer;
struct b_code;
struct b_symbol;
struct b_codewscope;
struct b_int32;
struct b_timestamp;
struct b_int64;
struct b_decimal128;
struct b_minkey;
struct b_maxkey;
namespace bson_value {
class value;
class view;
} // namespace bson_value
} // namespace types
namespace array {
class element;
} // namespace array
namespace document {
///
/// A variant view type that accesses values in serialized BSON documents.
///
/// Element functions as a variant type, where the kind of the element can be
/// interrogated by calling type(), the key can be extracted by calling key() and
/// a specific value can be extracted through get_X() accessors.
///
/// @relatesalso array::element
///
class BSONCXX_API element {
public:
///
/// Construct an invalid element.
///
/// This is useful when mapping the end iterator of a document or array
/// view.
///
element();
///
/// Conversion operator to bool which is true for valid elements
/// and false for invalid elements.
///
explicit operator bool() const;
///
/// Getter for the raw bson bytes the element points to.
///
/// @return a pointer to the raw bson bytes.
///
const std::uint8_t* raw() const;
///
/// Getter for length of the raw bson bytes the element points to.
///
/// @return a pointer to the length of the raw bson bytes.
///
std::uint32_t length() const;
///
/// Getter for the offset into the raw bson bytes the element points to.
///
/// @return the offset into the raw bson bytes.
///
std::uint32_t offset() const;
///
/// Getter for the type of the element.
///
/// @return the element's type.
///
/// @throws bsoncxx::exception if this element is invalid.
///
bsoncxx::type type() const;
///
/// Getter for the element's key.
///
/// @return the element's key.
///
/// @throws bsoncxx::exception if this element is invalid.
///
stdx::string_view key() const;
///
/// Getter for the element's key length.
///
/// @return the element's key length.
///
std::uint32_t keylen() const;
///
/// Getter for elements of the b_double type.
///
/// @throws bsoncxx::exception if this element is not a b_double.
///
/// @return the element's value.
///
types::b_double get_double() const;
///
/// Getter for elements of the b_string type.
///
/// @deprecated use document::element::get_string() instead.
///
/// @throws bsoncxx::exception if this element is not a b_string.
///
/// @return the element's value.
///
BSONCXX_DEPRECATED types::b_string get_utf8() const;
///
/// Getter for elements of the b_string type.
///
/// @throws bsoncxx::exception if this element is not a b_string.
///
/// @return the element's value.
///
types::b_string get_string() const;
///
/// Getter for elements of the b_document type.
///
/// @throws bsoncxx::exception if this element is not a b_document.
///
/// @return the element's value.
///
types::b_document get_document() const;
///
/// Getter for elements of the b_array type.
///
/// @throws bsoncxx::exception if this element is not a b_array.
///
/// @return the element's value.
///
types::b_array get_array() const;
///
/// Getter for elements of the b_binary type.
///
/// @throws bsoncxx::exception if this element is not a b_binary.
///
/// @return the element's value.
///
types::b_binary get_binary() const;
///
/// Getter for elements of the b_undefined type.
///
/// @throws bsoncxx::exception if this element is not a b_undefined.
///
/// @return the element's value.
///
types::b_undefined get_undefined() const;
///
/// Getter for elements of the b_oid type.
///
/// @throws bsoncxx::exception if this element is not a b_oid.
///
/// @return the element's value.
///
types::b_oid get_oid() const;
///
/// Getter for elements of the b_bool type.
///
/// @throws bsoncxx::exception if this element is not a b_bool.
///
/// @return the element's value.
///
types::b_bool get_bool() const;
///
/// Getter for elements of the b_date type.
///
/// @throws bsoncxx::exception if this element is not a b_date.
///
/// @return the element's value.
///
types::b_date get_date() const;
///
/// Getter for elements of the b_null type.
///
/// @throws bsoncxx::exception if this element is not a b_null.
///
/// @return the element's value.
///
types::b_null get_null() const;
///
/// Getter for elements of the b_regex type.
///
/// @throws bsoncxx::exception if this element is not a b_regex.
///
/// @return the element's value.
///
types::b_regex get_regex() const;
///
/// Getter for elements of the b_dbpointer type.
///
/// @throws bsoncxx::exception if this element is not a b_dbpointer.
///
/// @return the element's value.
///
types::b_dbpointer get_dbpointer() const;
///
/// Getter for elements of the b_code type.
///
/// @throws bsoncxx::exception if this element is not a b_code.
///
/// @return the element's value.
///
types::b_code get_code() const;
///
/// Getter for elements of the b_symbol type.
///
/// @throws bsoncxx::exception if this element is not a b_symbol.
///
/// @return the element's value.
///
types::b_symbol get_symbol() const;
///
/// Getter for elements of the b_codewscope type.
///
/// @throws bsoncxx::exception if this element is not a b_codewscope.
///
/// @return the element's value.
///
types::b_codewscope get_codewscope() const;
///
/// Getter for elements of the b_int32 type.
///
/// @throws bsoncxx::exception if this element is not a b_int32.
///
/// @return the element's value.
///
types::b_int32 get_int32() const;
///
/// Getter for elements of the b_timestamp type.
///
/// @throws bsoncxx::exception if this element is not a b_timestamp.
///
/// @return the element's value.
///
types::b_timestamp get_timestamp() const;
///
/// Getter for elements of the b_int64 type.
///
/// @throws bsoncxx::exception if this element is not a b_int64.
///
/// @return the element's value.
///
types::b_int64 get_int64() const;
///
/// Getter for elements of the b_decimal128 type.
///
/// @throws bsoncxx::exception if this element is not a b_decimal128.
///
/// @return the element's value.
///
types::b_decimal128 get_decimal128() const;
///
/// Getter for elements of the b_minkey type.
///
/// @throws bsoncxx::exception if this element is not a b_minkey.
///
/// @return the element's value.
///
types::b_minkey get_minkey() const;
///
/// Getter for elements of the b_maxkey type.
///
/// @throws bsoncxx::exception if this element is not a b_maxkey.
///
/// @return the element's value.
///
types::b_maxkey get_maxkey() const;
///
/// Getter for a types::bson_value::view variant wrapper of the value portion of the
/// element.
///
/// @return the element's value.
///
types::bson_value::view get_value() const;
///
/// Getter for a types::bson_value::value variant wrapper of the value portion of
/// the element. The returned object will make a copy of the buffer from this object.
///
/// @return an owning version of the element's value.
///
types::bson_value::value get_owning_value() const;
///
/// If this element is a document, finds the first element of the document
/// with the provided key. If there is no such element, an invalid
/// document::element will be returned. The runtime of operator[] is
/// linear in the length of the document.
///
/// If this element is not a document, an invalid document::element will
/// be returned.
///
/// @param key
/// The key to search for.
///
/// @return The matching element, if found, or an invalid element.
///
element operator[](stdx::string_view key) const;
///
/// If this element is an array, indexes into this BSON array. If the
/// index is out-of-bounds, an invalid array::element will be returned. As
/// BSON represents arrays as documents, the runtime of operator[] is
/// linear in the length of the array.
///
/// If this element is not an array, an invalid array::element will
/// be returned.
///
/// @param i
/// The index of the element.
///
/// @return The element if it exists, or an invalid element.
///
array::element operator[](std::uint32_t i) const;
private:
///
/// Construct an element as an offset into a buffer of bson bytes.
///
/// @param raw
/// A pointer to the raw bson bytes.
///
/// @param length
/// The size of the bson buffer.
///
/// @param offset
/// The element's offset into the buffer.
///
BSONCXX_PRIVATE explicit element(const std::uint8_t* raw,
std::uint32_t length,
std::uint32_t offset,
std::uint32_t keylen);
friend class view;
friend class array::element;
const std::uint8_t* _raw;
std::uint32_t _length;
std::uint32_t _offset;
std::uint32_t _keylen;
};
///
/// @{
///
/// Convenience methods to compare for equality against a bson_value.
///
/// Returns true if this element contains a bson_value that matches.
///
/// @relates element
///
BSONCXX_API bool BSONCXX_CALL operator==(const element& elem, const types::bson_value::view& v);
BSONCXX_API bool BSONCXX_CALL operator==(const types::bson_value::view& v, const element& elem);
///
/// @}
///
///
/// @{
///
/// Convenience methods to compare for equality against a bson_value.
///
/// Returns false if this element contains a bson_value that matches.
///
/// @relates element
///
BSONCXX_API bool BSONCXX_CALL operator!=(const element& elem, const types::bson_value::view& v);
BSONCXX_API bool BSONCXX_CALL operator!=(const types::bson_value::view& v, const element& elem);
///
/// @}
///
} // namespace document
BSONCXX_INLINE_NAMESPACE_END
} // namespace bsoncxx
#include <bsoncxx/config/postlude.hpp>