mirror of
https://github.com/LadybirdBrowser/ladybird.git
synced 2024-08-17 09:20:28 +03:00
359 lines
12 KiB
C++
359 lines
12 KiB
C++
/*
|
|
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#include <AK/CharacterTypes.h>
|
|
#include <AK/FloatingPointStringConversions.h>
|
|
#include <AK/JsonArray.h>
|
|
#include <AK/JsonObject.h>
|
|
#include <AK/JsonParser.h>
|
|
#include <math.h>
|
|
|
|
namespace AK {
|
|
|
|
constexpr bool is_space(int ch)
|
|
{
|
|
return ch == '\t' || ch == '\n' || ch == '\r' || ch == ' ';
|
|
}
|
|
|
|
// ECMA-404 9 String
|
|
// Boils down to
|
|
// STRING = "\"" *("[^\"\\]" | "\\" ("[\"\\bfnrt]" | "u[0-9A-Za-z]{4}")) "\""
|
|
// │├── " ──╮───────────────────────────────────────────────╭── " ──┤│
|
|
// │ │
|
|
// │ ╭───────────────────<─────────────────────╮ │
|
|
// │ │ │ │
|
|
// ╰──╰──╮───────────── [^"\\] ──────────────╭──╯──╯
|
|
// │ │
|
|
// ╰── \ ───╮──── ["\\bfnrt] ───────╭──╯
|
|
// │ │
|
|
// ╰─── u[0-9A-Za-z]{4} ──╯
|
|
//
|
|
ErrorOr<ByteString> JsonParser::consume_and_unescape_string()
|
|
{
|
|
if (!consume_specific('"'))
|
|
return Error::from_string_literal("JsonParser: Expected '\"'");
|
|
StringBuilder final_sb;
|
|
|
|
for (;;) {
|
|
// OPTIMIZATION: We try to append as many literal characters as possible at a time
|
|
// This also pre-checks some error conditions
|
|
// Note: All utf8 characters are either plain ascii, or have their most signifiant bit set,
|
|
// which puts the, above plain ascii in value, so they will always consist
|
|
// of a set of "legal" non-special bytes,
|
|
// hence we don't need to bother with a code-point iterator,
|
|
// as a simple byte iterator suffices, which GenericLexer provides by default
|
|
size_t literal_characters = 0;
|
|
for (;;) {
|
|
char ch = peek(literal_characters);
|
|
// Note: We get a 0 byte when we hit EOF
|
|
if (ch == 0)
|
|
return Error::from_string_literal("JsonParser: EOF while parsing String");
|
|
// Spec: All code points may be placed within the quotation marks except
|
|
// for the code points that must be escaped: quotation mark (U+0022),
|
|
// reverse solidus (U+005C), and the control characters U+0000 to U+001F.
|
|
// There are two-character escape sequence representations of some characters.
|
|
if (is_ascii_c0_control(ch))
|
|
return Error::from_string_literal("JsonParser: ASCII control sequence encountered");
|
|
if (ch == '"' || ch == '\\')
|
|
break;
|
|
++literal_characters;
|
|
}
|
|
final_sb.append(consume(literal_characters));
|
|
|
|
// We have checked all cases except end-of-string and escaped characters in the loop above,
|
|
// so we now only have to handle those two cases
|
|
char ch = peek();
|
|
|
|
if (ch == '"') {
|
|
consume();
|
|
break;
|
|
}
|
|
|
|
ignore(); // '\'
|
|
|
|
switch (peek()) {
|
|
case '\0':
|
|
return Error::from_string_literal("JsonParser: EOF while parsing String");
|
|
case '"':
|
|
case '\\':
|
|
case '/':
|
|
final_sb.append(consume());
|
|
break;
|
|
case 'b':
|
|
ignore();
|
|
final_sb.append('\b');
|
|
break;
|
|
case 'f':
|
|
ignore();
|
|
final_sb.append('\f');
|
|
break;
|
|
case 'n':
|
|
ignore();
|
|
final_sb.append('\n');
|
|
break;
|
|
case 'r':
|
|
ignore();
|
|
final_sb.append('\r');
|
|
break;
|
|
case 't':
|
|
ignore();
|
|
final_sb.append('\t');
|
|
break;
|
|
case 'u': {
|
|
ignore(); // 'u'
|
|
|
|
if (tell_remaining() < 4)
|
|
return Error::from_string_literal("JsonParser: EOF while parsing Unicode escape");
|
|
auto escaped_string = consume(4);
|
|
auto code_point = AK::StringUtils::convert_to_uint_from_hex(escaped_string);
|
|
if (!code_point.has_value()) {
|
|
dbgln("JsonParser: Error while parsing Unicode escape {}", escaped_string);
|
|
return Error::from_string_literal("JsonParser: Error while parsing Unicode escape");
|
|
}
|
|
// Note/FIXME: "To escape a code point that is not in the Basic Multilingual Plane, the character may be represented as a
|
|
// twelve-character sequence, encoding the UTF-16 surrogate pair corresponding to the code point. So for
|
|
// example, a string containing only the G clef character (U+1D11E) may be represented as "\uD834\uDD1E".
|
|
// However, whether a processor of JSON texts interprets such a surrogate pair as a single code point or as an
|
|
// explicit surrogate pair is a semantic decision that is determined by the specific processor."
|
|
// ~ECMA-404, 2nd Edition Dec. 2017, page 5
|
|
final_sb.append_code_point(code_point.value());
|
|
break;
|
|
}
|
|
default:
|
|
dbgln("JsonParser: Invalid escaped character '{}' ({:#x}) ", peek(), peek());
|
|
return Error::from_string_literal("JsonParser: Invalid escaped character");
|
|
}
|
|
}
|
|
|
|
return final_sb.to_byte_string();
|
|
}
|
|
|
|
ErrorOr<JsonValue> JsonParser::parse_object()
|
|
{
|
|
JsonObject object;
|
|
if (!consume_specific('{'))
|
|
return Error::from_string_literal("JsonParser: Expected '{'");
|
|
for (;;) {
|
|
ignore_while(is_space);
|
|
if (peek() == '}')
|
|
break;
|
|
ignore_while(is_space);
|
|
auto name = TRY(consume_and_unescape_string());
|
|
ignore_while(is_space);
|
|
if (!consume_specific(':'))
|
|
return Error::from_string_literal("JsonParser: Expected ':'");
|
|
ignore_while(is_space);
|
|
auto value = TRY(parse_helper());
|
|
object.set(name, move(value));
|
|
ignore_while(is_space);
|
|
if (peek() == '}')
|
|
break;
|
|
if (!consume_specific(','))
|
|
return Error::from_string_literal("JsonParser: Expected ','");
|
|
ignore_while(is_space);
|
|
if (peek() == '}')
|
|
return Error::from_string_literal("JsonParser: Unexpected '}'");
|
|
}
|
|
if (!consume_specific('}'))
|
|
return Error::from_string_literal("JsonParser: Expected '}'");
|
|
return JsonValue { move(object) };
|
|
}
|
|
|
|
ErrorOr<JsonValue> JsonParser::parse_array()
|
|
{
|
|
JsonArray array;
|
|
if (!consume_specific('['))
|
|
return Error::from_string_literal("JsonParser: Expected '['");
|
|
for (;;) {
|
|
ignore_while(is_space);
|
|
if (peek() == ']')
|
|
break;
|
|
auto element = TRY(parse_helper());
|
|
TRY(array.append(move(element)));
|
|
ignore_while(is_space);
|
|
if (peek() == ']')
|
|
break;
|
|
if (!consume_specific(','))
|
|
return Error::from_string_literal("JsonParser: Expected ','");
|
|
ignore_while(is_space);
|
|
if (peek() == ']')
|
|
return Error::from_string_literal("JsonParser: Unexpected ']'");
|
|
}
|
|
ignore_while(is_space);
|
|
if (!consume_specific(']'))
|
|
return Error::from_string_literal("JsonParser: Expected ']'");
|
|
return JsonValue { move(array) };
|
|
}
|
|
|
|
ErrorOr<JsonValue> JsonParser::parse_string()
|
|
{
|
|
auto string = TRY(consume_and_unescape_string());
|
|
return JsonValue(move(string));
|
|
}
|
|
|
|
ErrorOr<JsonValue> JsonParser::parse_number()
|
|
{
|
|
Vector<char, 32> number_buffer;
|
|
|
|
auto start_index = tell();
|
|
|
|
bool negative = false;
|
|
if (peek() == '-') {
|
|
number_buffer.append('-');
|
|
++m_index;
|
|
negative = true;
|
|
|
|
if (!is_ascii_digit(peek()))
|
|
return Error::from_string_literal("JsonParser: Unexpected '-' without further digits");
|
|
}
|
|
|
|
auto fallback_to_double_parse = [&]() -> ErrorOr<JsonValue> {
|
|
// FIXME: Since we know all the characters so far are ascii digits (and one . or e) we could
|
|
// use that in the floating point parser.
|
|
|
|
// The first part should be just ascii digits
|
|
StringView view = m_input.substring_view(start_index);
|
|
|
|
char const* start = view.characters_without_null_termination();
|
|
auto parse_result = parse_first_floating_point(start, start + view.length());
|
|
|
|
if (parse_result.parsed_value()) {
|
|
auto characters_parsed = parse_result.end_ptr - start;
|
|
m_index = start_index + characters_parsed;
|
|
|
|
return JsonValue(parse_result.value);
|
|
}
|
|
return Error::from_string_literal("JsonParser: Invalid floating point");
|
|
};
|
|
|
|
if (peek() == '0') {
|
|
if (is_ascii_digit(peek(1)))
|
|
return Error::from_string_literal("JsonParser: Cannot have leading zeros");
|
|
|
|
// Leading zeros are not allowed, however we can have a '.' or 'e' with
|
|
// valid digits after just a zero. These cases will be detected by having the next element
|
|
// start with a '.' or 'e'.
|
|
}
|
|
|
|
bool all_zero = true;
|
|
for (;;) {
|
|
char ch = peek();
|
|
if (ch == '.') {
|
|
if (!is_ascii_digit(peek(1)))
|
|
return Error::from_string_literal("JsonParser: Must have digits after decimal point");
|
|
|
|
return fallback_to_double_parse();
|
|
}
|
|
if (ch == 'e' || ch == 'E') {
|
|
char next = peek(1);
|
|
if (!is_ascii_digit(next) && ((next != '+' && next != '-') || !is_ascii_digit(peek(2))))
|
|
return Error::from_string_literal("JsonParser: Must have digits after exponent with an optional sign inbetween");
|
|
|
|
return fallback_to_double_parse();
|
|
}
|
|
|
|
if (is_ascii_digit(ch)) {
|
|
if (ch != '0')
|
|
all_zero = false;
|
|
|
|
number_buffer.append(ch);
|
|
++m_index;
|
|
continue;
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
// Negative zero is always a double
|
|
if (negative && all_zero)
|
|
return JsonValue(-0.0);
|
|
|
|
StringView number_string(number_buffer.data(), number_buffer.size());
|
|
|
|
auto to_unsigned_result = number_string.to_number<u64>();
|
|
if (to_unsigned_result.has_value()) {
|
|
if (*to_unsigned_result <= NumericLimits<u32>::max())
|
|
return JsonValue((u32)*to_unsigned_result);
|
|
|
|
return JsonValue(*to_unsigned_result);
|
|
} else if (auto signed_number = number_string.to_number<i64>(); signed_number.has_value()) {
|
|
|
|
if (*signed_number <= NumericLimits<i32>::max())
|
|
return JsonValue((i32)*signed_number);
|
|
|
|
return JsonValue(*signed_number);
|
|
}
|
|
|
|
// It's possible the unsigned value is bigger than u64 max
|
|
return fallback_to_double_parse();
|
|
}
|
|
|
|
ErrorOr<JsonValue> JsonParser::parse_true()
|
|
{
|
|
if (!consume_specific("true"sv))
|
|
return Error::from_string_literal("JsonParser: Expected 'true'");
|
|
return JsonValue(true);
|
|
}
|
|
|
|
ErrorOr<JsonValue> JsonParser::parse_false()
|
|
{
|
|
if (!consume_specific("false"sv))
|
|
return Error::from_string_literal("JsonParser: Expected 'false'");
|
|
return JsonValue(false);
|
|
}
|
|
|
|
ErrorOr<JsonValue> JsonParser::parse_null()
|
|
{
|
|
if (!consume_specific("null"sv))
|
|
return Error::from_string_literal("JsonParser: Expected 'null'");
|
|
return JsonValue {};
|
|
}
|
|
|
|
ErrorOr<JsonValue> JsonParser::parse_helper()
|
|
{
|
|
ignore_while(is_space);
|
|
auto type_hint = peek();
|
|
switch (type_hint) {
|
|
case '{':
|
|
return parse_object();
|
|
case '[':
|
|
return parse_array();
|
|
case '"':
|
|
return parse_string();
|
|
case '-':
|
|
case '0':
|
|
case '1':
|
|
case '2':
|
|
case '3':
|
|
case '4':
|
|
case '5':
|
|
case '6':
|
|
case '7':
|
|
case '8':
|
|
case '9':
|
|
return parse_number();
|
|
case 'f':
|
|
return parse_false();
|
|
case 't':
|
|
return parse_true();
|
|
case 'n':
|
|
return parse_null();
|
|
}
|
|
|
|
return Error::from_string_literal("JsonParser: Unexpected character");
|
|
}
|
|
|
|
ErrorOr<JsonValue> JsonParser::parse()
|
|
{
|
|
auto result = TRY(parse_helper());
|
|
ignore_while(is_space);
|
|
if (!is_eof())
|
|
return Error::from_string_literal("JsonParser: Didn't consume all input");
|
|
return result;
|
|
}
|
|
|
|
}
|