Kernel: Split the Plan9FileSystem.{cpp,h} file into smaller components

Kernel/FileSystem/Plan9FS/Message.cpp

@@ -0,0 +1,165 @@
+/*
+ * Copyright (c) 2020, Sergey Bugaev <bugaevc@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <Kernel/FileSystem/Plan9FS/FileSystem.h>
+#include <Kernel/FileSystem/Plan9FS/Inode.h>
+#include <Kernel/FileSystem/Plan9FS/Message.h>
+
+namespace Kernel {
+
+Plan9FSMessage& Plan9FSMessage::operator<<(u8 number)
+{
+    return append_number(number);
+}
+
+Plan9FSMessage& Plan9FSMessage::operator<<(u16 number)
+{
+    return append_number(number);
+}
+
+Plan9FSMessage& Plan9FSMessage::operator<<(u32 number)
+{
+    return append_number(number);
+}
+
+Plan9FSMessage& Plan9FSMessage::operator<<(u64 number)
+{
+    return append_number(number);
+}
+
+Plan9FSMessage& Plan9FSMessage::operator<<(StringView string)
+{
+    *this << static_cast<u16>(string.length());
+    // FIXME: Handle append failure.
+    (void)m_builder.append(string);
+    return *this;
+}
+
+void Plan9FSMessage::append_data(StringView data)
+{
+    *this << static_cast<u32>(data.length());
+    // FIXME: Handle append failure.
+    (void)m_builder.append(data);
+}
+
+Plan9FSMessage::Decoder& Plan9FSMessage::Decoder::operator>>(u8& number)
+{
+    return read_number(number);
+}
+
+Plan9FSMessage::Decoder& Plan9FSMessage::Decoder::operator>>(u16& number)
+{
+    return read_number(number);
+}
+
+Plan9FSMessage::Decoder& Plan9FSMessage::Decoder::operator>>(u32& number)
+{
+    return read_number(number);
+}
+
+Plan9FSMessage::Decoder& Plan9FSMessage::Decoder::operator>>(u64& number)
+{
+    return read_number(number);
+}
+
+Plan9FSMessage::Decoder& Plan9FSMessage::Decoder::operator>>(Plan9FSQIdentifier& qid)
+{
+    return *this >> qid.type >> qid.version >> qid.path;
+}
+
+Plan9FSMessage::Decoder& Plan9FSMessage::Decoder::operator>>(StringView& string)
+{
+    u16 length;
+    *this >> length;
+    VERIFY(length <= m_data.length());
+    string = m_data.substring_view(0, length);
+    m_data = m_data.substring_view_starting_after_substring(string);
+    return *this;
+}
+
+StringView Plan9FSMessage::Decoder::read_data()
+{
+    u32 length;
+    *this >> length;
+    VERIFY(length <= m_data.length());
+    auto data = m_data.substring_view(0, length);
+    m_data = m_data.substring_view_starting_after_substring(data);
+    return data;
+}
+
+Plan9FSMessage::Plan9FSMessage(Plan9FS& fs, Type type)
+    : m_builder(KBufferBuilder::try_create().release_value()) // FIXME: Don't assume KBufferBuilder allocation success.
+    , m_tag(fs.allocate_tag())
+    , m_type(type)
+    , m_have_been_built(false)
+{
+    u32 size_placeholder = 0;
+    *this << size_placeholder << (u8)type << m_tag;
+}
+
+Plan9FSMessage::Plan9FSMessage(NonnullOwnPtr<KBuffer>&& buffer)
+    : m_built { move(buffer), Decoder({ buffer->bytes() }) }
+    , m_have_been_built(true)
+{
+    u32 size;
+    u8 raw_type;
+    *this >> size >> raw_type >> m_tag;
+    m_type = (Type)raw_type;
+}
+
+Plan9FSMessage::~Plan9FSMessage()
+{
+    if (m_have_been_built) {
+        m_built.buffer.~NonnullOwnPtr<KBuffer>();
+        m_built.decoder.~Decoder();
+    } else {
+        m_builder.~KBufferBuilder();
+    }
+}
+
+Plan9FSMessage& Plan9FSMessage::operator=(Plan9FSMessage&& message)
+{
+    m_tag = message.m_tag;
+    m_type = message.m_type;
+
+    if (m_have_been_built) {
+        m_built.buffer.~NonnullOwnPtr<KBuffer>();
+        m_built.decoder.~Decoder();
+    } else {
+        m_builder.~KBufferBuilder();
+    }
+
+    m_have_been_built = message.m_have_been_built;
+    if (m_have_been_built) {
+        new (&m_built.buffer) NonnullOwnPtr<KBuffer>(move(message.m_built.buffer));
+        new (&m_built.decoder) Decoder(move(message.m_built.decoder));
+    } else {
+        new (&m_builder) KBufferBuilder(move(message.m_builder));
+    }
+
+    return *this;
+}
+
+KBuffer const& Plan9FSMessage::build()
+{
+    VERIFY(!m_have_been_built);
+
+    auto tmp_buffer = m_builder.build();
+
+    // FIXME: We should not assume success here.
+    VERIFY(tmp_buffer);
+
+    m_have_been_built = true;
+    m_builder.~KBufferBuilder();
+
+    new (&m_built.buffer) NonnullOwnPtr<KBuffer>(tmp_buffer.release_nonnull());
+    new (&m_built.decoder) Decoder({ m_built.buffer->data(), m_built.buffer->size() });
+    u32* size = reinterpret_cast<u32*>(m_built.buffer->data());
+    *size = m_built.buffer->size();
+    return *m_built.buffer;
+}
+
+}