ladybird/Libraries/LibWeb/CSS/FontLoading.cpp
Aliaksandr Kalenik 4cd8e84dff LibGfx+LibWeb: Keep loaded font bytes shareable
Future compositor-side rendering will need WebContent to share typefaces
with the compositor process over IPC. If a typeface already keeps its
backing bytes in anonymous shared memory, IPC encoding can clone that
buffer handle instead of allocating a new shared buffer and copying the
same font data during upload.
2026-05-19 09:20:38 +02:00

81 lines
3 KiB
C++

/*
* Copyright (c) 2026-present, the Ladybird developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Endian.h>
#include <LibCore/EventLoop.h>
#include <LibGfx/Font/WOFF/Loader.h>
#include <LibGfx/Font/WOFF2/Loader.h>
#include <LibThreading/ThreadPool.h>
#include <LibWeb/CSS/FontLoading.h>
namespace Web::CSS {
static constexpr u32 woff2_signature = 0x774F4632;
bool requires_off_thread_vector_font_preparation(ByteBuffer const& data, Optional<ByteString> const& mime_type_essence)
{
if (mime_type_essence == "font/woff2"sv || mime_type_essence == "application/font-woff2"sv)
return true;
if (data.size() < sizeof(u32))
return false;
auto signature = *bit_cast<BigEndian<u32> const*>(data.data());
return signature == woff2_signature;
}
ErrorOr<NonnullRefPtr<Gfx::Typeface const>> try_load_vector_font(ByteBuffer const& data, Optional<ByteString> const& mime_type_essence)
{
auto try_ttf = [&]() -> ErrorOr<NonnullRefPtr<Gfx::Typeface const>> {
return Gfx::Typeface::try_load_from_temporary_memory(data);
};
auto try_woff = [&]() -> ErrorOr<NonnullRefPtr<Gfx::Typeface const>> {
return WOFF::try_load_from_bytes(data);
};
auto try_woff2 = [&]() -> ErrorOr<NonnullRefPtr<Gfx::Typeface const>> {
return WOFF2::try_load_from_bytes(data);
};
if (mime_type_essence.has_value()) {
if (*mime_type_essence == "font/ttf"sv || *mime_type_essence == "application/x-font-ttf"sv || *mime_type_essence == "font/otf"sv)
return try_ttf();
if (*mime_type_essence == "font/woff"sv || *mime_type_essence == "application/font-woff"sv)
return try_woff();
if (*mime_type_essence == "font/woff2"sv || *mime_type_essence == "application/font-woff2"sv)
return try_woff2();
} else {
if (auto result = try_ttf(); !result.is_error())
return result.release_value();
if (auto result = try_woff(); !result.is_error())
return result.release_value();
if (auto result = try_woff2(); !result.is_error())
return result.release_value();
}
return Error::from_string_literal("Automatic format detection failed");
}
void prepare_vector_font_data_off_thread(ByteBuffer data, Function<void(ErrorOr<Core::AnonymousBuffer>)>&& on_complete)
{
// Keep the callback on the origin thread so any GC roots it captures are
// also destroyed there.
auto* callback = new Function<void(ErrorOr<Core::AnonymousBuffer>)>(move(on_complete));
auto event_loop_weak = Core::EventLoop::current_weak();
Threading::ThreadPool::the().submit(
[data = move(data), callback, event_loop_weak = move(event_loop_weak)]() mutable {
auto result = WOFF2::convert_to_ttf(data);
auto origin = event_loop_weak->take();
if (!origin)
return;
origin->deferred_invoke([callback, result = move(result)]() mutable {
(*callback)(move(result));
delete callback;
});
});
}
}