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
Notes: sideshowbarker 2024-07-17 01:38:22 +09:00
5 changed files with 23 additions and 14 deletions

View file

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

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@ -109,8 +109,8 @@ public:
} }
template<typename T> template<typename T>
requires(IsTriviallyDestructible<T>) requires(Traits<T>::is_trivially_serializable())
ErrorOr<T> read_trivial_value() ErrorOr<T> read_value()
{ {
alignas(T) u8 buffer[sizeof(T)] = {}; alignas(T) u8 buffer[sizeof(T)] = {};
TRY(read_entire_buffer({ &buffer, sizeof(buffer) })); TRY(read_entire_buffer({ &buffer, sizeof(buffer) }));
@ -118,8 +118,8 @@ public:
} }
template<typename T> template<typename T>
requires(IsTriviallyDestructible<T>) requires(Traits<T>::is_trivially_serializable())
ErrorOr<void> write_trivial_value(T const& value) ErrorOr<void> write_value(T const& value)
{ {
return write_entire_buffer({ &value, sizeof(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('.'); auto parts = as_string().split_view('.');
for (auto& part : parts) { 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_entire_buffer(part.bytes()));
} }
TRY(stream.write_trivial_value('\0')); TRY(stream.write_value('\0'));
return {}; return {};
} }

View file

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

View file

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