AK: Define our own concept of "trivially serializable"

While at it, rename the `read_trivial_value` and `write_trivial_value`
functions to `read_value` and `write_value` respectively, since we'll
add compatibility for non-trivial types down the line.
This commit is contained in:
Tim Schumacher 2023-01-14 21:13:29 +01:00 committed by Tim Flynn
parent 6777cb0975
commit d1711f1cef
5 changed files with 23 additions and 14 deletions

View file

@ -20,6 +20,7 @@ struct GenericTraits {
using PeekType = T&;
using ConstPeekType = T const&;
static constexpr bool is_trivial() { return false; }
static constexpr bool is_trivially_serializable() { return false; }
static constexpr bool equals(T const& a, T const& b) { return a == b; }
template<Concepts::HashCompatible<T> U>
static bool equals(U const& a, T const& b) { return a == b; }
@ -32,6 +33,7 @@ struct Traits : public GenericTraits<T> {
template<Integral T>
struct Traits<T> : public GenericTraits<T> {
static constexpr bool is_trivial() { return true; }
static constexpr bool is_trivially_serializable() { return true; }
static constexpr unsigned hash(T value)
{
if constexpr (sizeof(T) < 8)
@ -45,6 +47,7 @@ struct Traits<T> : public GenericTraits<T> {
template<FloatingPoint T>
struct Traits<T> : public GenericTraits<T> {
static constexpr bool is_trivial() { return true; }
static constexpr bool is_trivially_serializable() { return true; }
static constexpr unsigned hash(T value)
{
if constexpr (sizeof(T) < 8)
@ -65,6 +68,7 @@ template<Enum T>
struct Traits<T> : public GenericTraits<T> {
static unsigned hash(T value) { return Traits<UnderlyingType<T>>::hash(to_underlying(value)); }
static constexpr bool is_trivial() { return Traits<UnderlyingType<T>>::is_trivial(); }
static constexpr bool is_trivially_serializable() { return Traits<UnderlyingType<T>>::is_trivially_serializable(); }
};
template<typename T>

View file

@ -109,8 +109,8 @@ public:
}
template<typename T>
requires(IsTriviallyDestructible<T>)
ErrorOr<T> read_trivial_value()
requires(Traits<T>::is_trivially_serializable())
ErrorOr<T> read_value()
{
alignas(T) u8 buffer[sizeof(T)] = {};
TRY(read_entire_buffer({ &buffer, sizeof(buffer) }));
@ -118,8 +118,8 @@ public:
}
template<typename T>
requires(IsTriviallyDestructible<T>)
ErrorOr<void> write_trivial_value(T const& value)
requires(Traits<T>::is_trivially_serializable())
ErrorOr<void> write_value(T const& value)
{
return write_entire_buffer({ &value, sizeof(value) });
}

View file

@ -79,10 +79,10 @@ ErrorOr<void> Name::write_to_stream(Core::Stream::Stream& stream) const
{
auto parts = as_string().split_view('.');
for (auto& part : parts) {
TRY(stream.write_trivial_value<u8>(part.length()));
TRY(stream.write_value<u8>(part.length()));
TRY(stream.write_entire_buffer(part.bytes()));
}
TRY(stream.write_trivial_value('\0'));
TRY(stream.write_value('\0'));
return {};
}

View file

@ -51,23 +51,23 @@ ErrorOr<ByteBuffer> Packet::to_byte_buffer() const
Core::Stream::AllocatingMemoryStream stream;
TRY(stream.write_trivial_value(header));
TRY(stream.write_value(header));
for (auto& question : m_questions) {
TRY(question.name().write_to_stream(stream));
TRY(stream.write_trivial_value(htons((u16)question.record_type())));
TRY(stream.write_trivial_value(htons(question.raw_class_code())));
TRY(stream.write_value(htons((u16)question.record_type())));
TRY(stream.write_value(htons(question.raw_class_code())));
}
for (auto& answer : m_answers) {
TRY(answer.name().write_to_stream(stream));
TRY(stream.write_trivial_value(htons((u16)answer.type())));
TRY(stream.write_trivial_value(htons(answer.raw_class_code())));
TRY(stream.write_trivial_value(htonl(answer.ttl())));
TRY(stream.write_value(htons((u16)answer.type())));
TRY(stream.write_value(htons(answer.raw_class_code())));
TRY(stream.write_value(htonl(answer.ttl())));
if (answer.type() == RecordType::PTR) {
Name name { answer.record_data() };
TRY(stream.write_trivial_value(htons(name.serialized_size())));
TRY(stream.write_value(htons(name.serialized_size())));
TRY(name.write_to_stream(stream));
} else {
TRY(stream.write_trivial_value(htons(answer.record_data().length())));
TRY(stream.write_value(htons(answer.record_data().length())));
TRY(stream.write_entire_buffer(answer.record_data().bytes()));
}
}

View file

@ -97,3 +97,8 @@ private:
static_assert(sizeof(PacketHeader) == 12);
}
template<>
struct AK::Traits<DNS::PacketHeader> : public AK::GenericTraits<DNS::PacketHeader> {
static constexpr bool is_trivially_serializable() { return true; }
};