ladybird/Kernel/FileSystem/Custody.cpp
Andreas Kling 728c3fbd14 Kernel: Use RefPtr instead of LockRefPtr for Custody
By protecting all the RefPtr<Custody> objects that may be accessed from
multiple threads at the same time (with spinlocks), we remove the need
for using LockRefPtr<Custody> (which is basically a RefPtr with a
built-in spinlock.)
2022-08-21 12:25:14 +02:00

89 lines
2.7 KiB
C++

/*
* Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/RefPtr.h>
#include <AK/Singleton.h>
#include <AK/StringBuilder.h>
#include <AK/StringView.h>
#include <AK/Vector.h>
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/FileSystem/Inode.h>
namespace Kernel {
static Singleton<SpinlockProtected<Custody::AllCustodiesList>> s_all_instances;
SpinlockProtected<Custody::AllCustodiesList>& Custody::all_instances()
{
return s_all_instances;
}
ErrorOr<NonnullRefPtr<Custody>> Custody::try_create(Custody* parent, StringView name, Inode& inode, int mount_flags)
{
return all_instances().with([&](auto& all_custodies) -> ErrorOr<NonnullRefPtr<Custody>> {
for (Custody& custody : all_custodies) {
if (custody.parent() == parent
&& custody.name() == name
&& &custody.inode() == &inode
&& custody.mount_flags() == mount_flags) {
return NonnullRefPtr { custody };
}
}
auto name_kstring = TRY(KString::try_create(name));
auto custody = TRY(adopt_nonnull_ref_or_enomem(new (nothrow) Custody(parent, move(name_kstring), inode, mount_flags)));
all_custodies.prepend(*custody);
return custody;
});
}
Custody::Custody(Custody* parent, NonnullOwnPtr<KString> name, Inode& inode, int mount_flags)
: m_parent(parent)
, m_name(move(name))
, m_inode(inode)
, m_mount_flags(mount_flags)
{
}
Custody::~Custody() = default;
ErrorOr<NonnullOwnPtr<KString>> Custody::try_serialize_absolute_path() const
{
if (!parent())
return KString::try_create("/"sv);
Vector<Custody const*, 32> custody_chain;
size_t path_length = 0;
for (auto const* custody = this; custody; custody = custody->parent()) {
TRY(custody_chain.try_append(custody));
path_length += custody->m_name->length() + 1;
}
VERIFY(path_length > 0);
char* buffer;
auto string = TRY(KString::try_create_uninitialized(path_length - 1, buffer));
size_t string_index = 0;
for (size_t custody_index = custody_chain.size() - 1; custody_index > 0; --custody_index) {
buffer[string_index] = '/';
++string_index;
auto const& custody_name = *custody_chain[custody_index - 1]->m_name;
__builtin_memcpy(buffer + string_index, custody_name.characters(), custody_name.length());
string_index += custody_name.length();
}
VERIFY(string->length() == string_index);
buffer[string_index] = 0;
return string;
}
bool Custody::is_readonly() const
{
if (m_mount_flags & MS_RDONLY)
return true;
return m_inode->fs().is_readonly();
}
}