vn-verdnaturachat/ios/Pods/Folly/folly/json.h

199 lines
6.1 KiB
C++

/*
* Copyright 2011-present Facebook, 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.
*/
/**
*
* Serialize and deserialize folly::dynamic values as JSON.
*
* Before you use this you should probably understand the basic
* concepts in the JSON type system:
*
* Value : String | Bool | Null | Object | Array | Number
* String : UTF-8 sequence
* Object : (String, Value) pairs, with unique String keys
* Array : ordered list of Values
* Null : null
* Bool : true | false
* Number : (representation unspecified)
*
* ... That's about it. For more information see http://json.org or
* look up RFC 4627.
*
* If your dynamic has anything illegal with regard to this type
* system, the serializer will throw.
*
* @author Jordan DeLong <delong.j@fb.com>
*/
#pragma once
#include <iosfwd>
#include <string>
#include <folly/Function.h>
#include <folly/Range.h>
#include <folly/dynamic.h>
namespace folly {
//////////////////////////////////////////////////////////////////////
namespace json {
struct serialization_opts {
explicit serialization_opts()
: allow_non_string_keys(false),
javascript_safe(false),
pretty_formatting(false),
encode_non_ascii(false),
validate_utf8(false),
allow_trailing_comma(false),
sort_keys(false),
skip_invalid_utf8(false),
allow_nan_inf(false),
double_mode(double_conversion::DoubleToStringConverter::SHORTEST),
double_num_digits(0), // ignored when mode is SHORTEST
double_fallback(false),
parse_numbers_as_strings(false),
recursion_limit(100),
extra_ascii_to_escape_bitmap{{0, 0}} {}
// If true, keys in an object can be non-strings. (In strict
// JSON, object keys must be strings.) This is used by dynamic's
// operator<<.
bool allow_non_string_keys;
/*
* If true, refuse to serialize 64-bit numbers that cannot be
* precisely represented by fit a double---instead, throws an
* exception if the document contains this.
*/
bool javascript_safe;
// If true, the serialized json will contain space and newlines to
// try to be minimally "pretty".
bool pretty_formatting;
// If true, non-ASCII utf8 characters would be encoded as \uXXXX:
// - if the code point is in [U+0000..U+FFFF] => encode as a single \uXXXX
// - if the code point is > U+FFFF => encode as 2 UTF-16 surrogate pairs.
bool encode_non_ascii;
// Check that strings are valid utf8
bool validate_utf8;
// Allow trailing comma in lists of values / items
bool allow_trailing_comma;
// Sort keys of all objects before printing out (potentially slow)
// using dynamic::operator<.
// Has no effect if sort_keys_by is set.
bool sort_keys;
// Sort keys of all objects before printing out (potentially slow)
// using the provided less functor.
Function<bool(dynamic const&, dynamic const&) const> sort_keys_by;
// Replace invalid utf8 characters with U+FFFD and continue
bool skip_invalid_utf8;
// true to allow NaN or INF values
bool allow_nan_inf;
// Options for how to print floating point values. See Conv.h
// toAppend implementation for floating point for more info
double_conversion::DoubleToStringConverter::DtoaMode double_mode;
unsigned int double_num_digits;
// Fallback to double when a value that looks like integer is too big to
// fit in an int64_t. Can result in loss a of precision.
bool double_fallback;
// Do not parse numbers. Instead, store them as strings and leave the
// conversion up to the user.
bool parse_numbers_as_strings;
// Recursion limit when parsing.
unsigned int recursion_limit;
// Bitmap representing ASCII characters to escape with unicode
// representations. The least significant bit of the first in the pair is
// ASCII value 0; the most significant bit of the second in the pair is ASCII
// value 127. Some specific characters in this range are always escaped
// regardless of the bitmask - namely characters less than 0x20, \, and ".
std::array<uint64_t, 2> extra_ascii_to_escape_bitmap;
};
/*
* Generates a bitmap with bits set for each of the ASCII characters provided
* for use in the serialization_opts extra_ascii_to_escape_bitmap option. If any
* characters are not valid ASCII, they are ignored.
*/
std::array<uint64_t, 2> buildExtraAsciiToEscapeBitmap(StringPiece chars);
/*
* Main JSON serialization routine taking folly::dynamic parameters.
* For the most common use cases there are simpler functions in the
* main folly namespace below.
*/
std::string serialize(dynamic const&, serialization_opts const&);
/*
* Escape a string so that it is legal to print it in JSON text and
* append the result to out.
*/
void escapeString(
StringPiece input,
std::string& out,
const serialization_opts& opts);
/*
* Strip all C99-like comments (i.e. // and / * ... * /)
*/
std::string stripComments(StringPiece jsonC);
} // namespace json
//////////////////////////////////////////////////////////////////////
/*
* Parse a json blob out of a range and produce a dynamic representing
* it.
*/
dynamic parseJson(StringPiece, json::serialization_opts const&);
dynamic parseJson(StringPiece);
/*
* Serialize a dynamic into a json string.
*/
std::string toJson(dynamic const&);
/*
* Same as the above, except format the json with some minimal
* indentation.
*/
std::string toPrettyJson(dynamic const&);
/*
* Printer for GTest.
* Uppercase name to fill GTest's API, which calls this method through ADL.
*/
void PrintTo(const dynamic&, std::ostream*);
//////////////////////////////////////////////////////////////////////
} // namespace folly