ladybird/Kernel/FileSystem/Custody.cpp
Idan Horowitz 81e23617d6 Kernel: Port Custody to ListedRefCounted
Custody's unref is one of many implementions of ListedRefCounted's
behaviour in the Kernel, which results in avoidable bugs caused by
the fragmentation of the implementations. This commit starts the work
of replacing all custom implementations with ListedRefCounted by
porting Custody to it.
2021-12-29 12:04:15 +01:00

105 lines
3.1 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#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<MutexProtected<Custody::AllCustodiesList>> s_all_instances;
MutexProtected<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_exclusive([&](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()
{
}
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()) {
custody_chain.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;
}
String Custody::absolute_path() const
{
if (!parent())
return "/";
Vector<Custody const*, 32> custody_chain;
for (auto const* custody = this; custody; custody = custody->parent())
custody_chain.append(custody);
StringBuilder builder;
for (int i = custody_chain.size() - 2; i >= 0; --i) {
builder.append('/');
builder.append(custody_chain[i]->name());
}
return builder.to_string();
}
bool Custody::is_readonly() const
{
if (m_mount_flags & MS_RDONLY)
return true;
return m_inode->fs().is_readonly();
}
}