mirror of
https://github.com/LadybirdBrowser/ladybird.git
synced 2024-11-22 15:40:19 +00:00
292 lines
8.4 KiB
C++
292 lines
8.4 KiB
C++
/*
|
|
* Copyright (c) 2020, Benoit Lormeau <blormeau@outlook.com>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#include <AK/Assertions.h>
|
|
#include <AK/ByteString.h>
|
|
#include <AK/CharacterTypes.h>
|
|
#include <AK/GenericLexer.h>
|
|
#include <AK/ScopeGuard.h>
|
|
#include <AK/StringBuilder.h>
|
|
#include <AK/Utf16View.h>
|
|
|
|
namespace AK {
|
|
// Consume a number of characters
|
|
StringView GenericLexer::consume(size_t count)
|
|
{
|
|
if (count == 0)
|
|
return {};
|
|
|
|
size_t start = m_index;
|
|
size_t length = min(count, m_input.length() - m_index);
|
|
m_index += length;
|
|
|
|
return m_input.substring_view(start, length);
|
|
}
|
|
|
|
// Consume the rest of the input
|
|
StringView GenericLexer::consume_all()
|
|
{
|
|
if (is_eof())
|
|
return {};
|
|
|
|
auto rest = m_input.substring_view(m_index, m_input.length() - m_index);
|
|
m_index = m_input.length();
|
|
return rest;
|
|
}
|
|
|
|
// Consume until a new line is found
|
|
StringView GenericLexer::consume_line()
|
|
{
|
|
size_t start = m_index;
|
|
while (!is_eof() && peek() != '\r' && peek() != '\n')
|
|
m_index++;
|
|
size_t length = m_index - start;
|
|
|
|
consume_specific('\r');
|
|
consume_specific('\n');
|
|
|
|
if (length == 0)
|
|
return {};
|
|
return m_input.substring_view(start, length);
|
|
}
|
|
|
|
// Consume and return characters until `stop` is peek'd
|
|
StringView GenericLexer::consume_until(char stop)
|
|
{
|
|
size_t start = m_index;
|
|
while (!is_eof() && peek() != stop)
|
|
m_index++;
|
|
size_t length = m_index - start;
|
|
|
|
if (length == 0)
|
|
return {};
|
|
return m_input.substring_view(start, length);
|
|
}
|
|
|
|
// Consume and return characters until the string `stop` is found
|
|
StringView GenericLexer::consume_until(char const* stop)
|
|
{
|
|
size_t start = m_index;
|
|
while (!is_eof() && !next_is(stop))
|
|
m_index++;
|
|
size_t length = m_index - start;
|
|
|
|
if (length == 0)
|
|
return {};
|
|
return m_input.substring_view(start, length);
|
|
}
|
|
|
|
// Consume and return characters until the string `stop` is found
|
|
StringView GenericLexer::consume_until(StringView stop)
|
|
{
|
|
size_t start = m_index;
|
|
while (!is_eof() && !next_is(stop))
|
|
m_index++;
|
|
size_t length = m_index - start;
|
|
|
|
if (length == 0)
|
|
return {};
|
|
return m_input.substring_view(start, length);
|
|
}
|
|
|
|
/*
|
|
* Consume a string surrounded by single or double quotes. The returned
|
|
* StringView does not include the quotes. An escape character can be provided
|
|
* to capture the enclosing quotes. Please note that the escape character will
|
|
* still be in the resulting StringView
|
|
*/
|
|
StringView GenericLexer::consume_quoted_string(char escape_char)
|
|
{
|
|
if (!next_is(is_quote))
|
|
return {};
|
|
|
|
char quote_char = consume();
|
|
size_t start = m_index;
|
|
while (!is_eof()) {
|
|
if (next_is(escape_char))
|
|
m_index++;
|
|
else if (next_is(quote_char))
|
|
break;
|
|
m_index++;
|
|
}
|
|
size_t length = m_index - start;
|
|
|
|
if (peek() != quote_char) {
|
|
// Restore the index in case the string is unterminated
|
|
m_index = start - 1;
|
|
return {};
|
|
}
|
|
|
|
// Ignore closing quote
|
|
ignore();
|
|
|
|
return m_input.substring_view(start, length);
|
|
}
|
|
|
|
template<Integral T>
|
|
ErrorOr<T> GenericLexer::consume_decimal_integer()
|
|
{
|
|
using UnsignedT = MakeUnsigned<T>;
|
|
|
|
ArmedScopeGuard rollback { [&, rollback_position = m_index] {
|
|
m_index = rollback_position;
|
|
} };
|
|
|
|
bool has_minus_sign = false;
|
|
|
|
if (next_is('+') || next_is('-'))
|
|
if (consume() == '-')
|
|
has_minus_sign = true;
|
|
|
|
StringView number_view = consume_while(is_ascii_digit);
|
|
if (number_view.is_empty())
|
|
return Error::from_errno(EINVAL);
|
|
|
|
auto maybe_number = StringUtils::convert_to_uint<UnsignedT>(number_view, TrimWhitespace::No);
|
|
if (!maybe_number.has_value())
|
|
return Error::from_errno(ERANGE);
|
|
auto number = maybe_number.value();
|
|
|
|
if (!has_minus_sign) {
|
|
if (NumericLimits<T>::max() < number) // This is only possible in a signed case.
|
|
return Error::from_errno(ERANGE);
|
|
|
|
rollback.disarm();
|
|
return number;
|
|
} else {
|
|
if constexpr (IsUnsigned<T>) {
|
|
if (number == 0) {
|
|
rollback.disarm();
|
|
return 0;
|
|
}
|
|
return Error::from_errno(ERANGE);
|
|
} else {
|
|
static constexpr UnsignedT max_value = static_cast<UnsignedT>(NumericLimits<T>::max()) + 1;
|
|
if (number > max_value)
|
|
return Error::from_errno(ERANGE);
|
|
rollback.disarm();
|
|
return -number;
|
|
}
|
|
}
|
|
}
|
|
|
|
LineTrackingLexer::Position LineTrackingLexer::position_for(size_t index) const
|
|
{
|
|
auto& [cached_index, cached_line, cached_column] = m_cached_position;
|
|
|
|
if (cached_index <= index) {
|
|
for (size_t i = cached_index; i < index; ++i) {
|
|
if (m_input[i] == '\n')
|
|
++cached_line, cached_column = 0;
|
|
else
|
|
++cached_column;
|
|
}
|
|
} else {
|
|
auto lines_backtracked = m_input.substring_view(index, cached_index - index).count('\n');
|
|
cached_line -= lines_backtracked;
|
|
if (lines_backtracked == 0) {
|
|
cached_column -= cached_index - index;
|
|
} else {
|
|
auto current_line_start = m_input.substring_view(0, index).find_last('\n').value_or(0);
|
|
cached_column = index - current_line_start;
|
|
}
|
|
}
|
|
cached_index = index;
|
|
return m_cached_position;
|
|
}
|
|
|
|
template ErrorOr<u8> GenericLexer::consume_decimal_integer<u8>();
|
|
template ErrorOr<i8> GenericLexer::consume_decimal_integer<i8>();
|
|
template ErrorOr<u16> GenericLexer::consume_decimal_integer<u16>();
|
|
template ErrorOr<i16> GenericLexer::consume_decimal_integer<i16>();
|
|
template ErrorOr<u32> GenericLexer::consume_decimal_integer<u32>();
|
|
template ErrorOr<i32> GenericLexer::consume_decimal_integer<i32>();
|
|
template ErrorOr<u64> GenericLexer::consume_decimal_integer<u64>();
|
|
template ErrorOr<i64> GenericLexer::consume_decimal_integer<i64>();
|
|
|
|
Optional<ByteString> GenericLexer::consume_and_unescape_string(char escape_char)
|
|
{
|
|
auto view = consume_quoted_string(escape_char);
|
|
if (view.is_null())
|
|
return {};
|
|
|
|
StringBuilder builder;
|
|
for (size_t i = 0; i < view.length(); ++i)
|
|
builder.append(consume_escaped_character(escape_char));
|
|
return builder.to_byte_string();
|
|
}
|
|
|
|
auto GenericLexer::consume_escaped_code_point(bool combine_surrogate_pairs) -> Result<u32, UnicodeEscapeError>
|
|
{
|
|
if (!consume_specific("\\u"sv))
|
|
return UnicodeEscapeError::MalformedUnicodeEscape;
|
|
|
|
if (next_is('{'))
|
|
return decode_code_point();
|
|
return decode_single_or_paired_surrogate(combine_surrogate_pairs);
|
|
}
|
|
|
|
auto GenericLexer::decode_code_point() -> Result<u32, UnicodeEscapeError>
|
|
{
|
|
bool starts_with_open_bracket = consume_specific('{');
|
|
VERIFY(starts_with_open_bracket);
|
|
|
|
u32 code_point = 0;
|
|
|
|
while (true) {
|
|
if (!next_is(is_ascii_hex_digit))
|
|
return UnicodeEscapeError::MalformedUnicodeEscape;
|
|
|
|
auto new_code_point = (code_point << 4u) | parse_ascii_hex_digit(consume());
|
|
if (new_code_point < code_point)
|
|
return UnicodeEscapeError::UnicodeEscapeOverflow;
|
|
|
|
code_point = new_code_point;
|
|
if (consume_specific('}'))
|
|
break;
|
|
}
|
|
|
|
if (is_unicode(code_point))
|
|
return code_point;
|
|
return UnicodeEscapeError::UnicodeEscapeOverflow;
|
|
}
|
|
|
|
auto GenericLexer::decode_single_or_paired_surrogate(bool combine_surrogate_pairs) -> Result<u32, UnicodeEscapeError>
|
|
{
|
|
constexpr size_t surrogate_length = 4;
|
|
|
|
auto decode_one_surrogate = [&]() -> Optional<u16> {
|
|
u16 surrogate = 0;
|
|
|
|
for (size_t i = 0; i < surrogate_length; ++i) {
|
|
if (!next_is(is_ascii_hex_digit))
|
|
return {};
|
|
|
|
surrogate = (surrogate << 4u) | parse_ascii_hex_digit(consume());
|
|
}
|
|
|
|
return surrogate;
|
|
};
|
|
|
|
auto high_surrogate = decode_one_surrogate();
|
|
if (!high_surrogate.has_value())
|
|
return UnicodeEscapeError::MalformedUnicodeEscape;
|
|
if (!Utf16View::is_high_surrogate(*high_surrogate))
|
|
return *high_surrogate;
|
|
if (!combine_surrogate_pairs || !consume_specific("\\u"sv))
|
|
return *high_surrogate;
|
|
|
|
auto low_surrogate = decode_one_surrogate();
|
|
if (!low_surrogate.has_value())
|
|
return UnicodeEscapeError::MalformedUnicodeEscape;
|
|
if (Utf16View::is_low_surrogate(*low_surrogate))
|
|
return Utf16View::decode_surrogate_pair(*high_surrogate, *low_surrogate);
|
|
|
|
retreat(6);
|
|
return *high_surrogate;
|
|
}
|
|
|
|
}
|