ladybird/Kernel/FileSystem/Custody.cpp
Andreas Kling 8adadf8a46 FileSystem: Reuse existing custodies when possible, and keep them updated.
Walk the custody cache and try to reuse an existing one when possible.
The VFS is responsible for updating them when something happens that would
cause the described relationship to change.

This is definitely not perfect but it does work for the basic scenarios like
renaming and removing directory entries.
2019-05-31 15:22:52 +02:00

86 lines
2.3 KiB
C++

#include <AK/HashTable.h>
#include <AK/StringBuilder.h>
#include <Kernel/FileSystem/Custody.h>
#include <Kernel/FileSystem/Inode.h>
#include <Kernel/Lock.h>
static Lockable<HashTable<Custody*>>& all_custodies()
{
static Lockable<HashTable<Custody*>>* table;
if (!table)
table = new Lockable<HashTable<Custody*>>;
return *table;
}
Custody* Custody::get_if_cached(Custody* parent, const String& name)
{
LOCKER(all_custodies().lock());
for (auto& custody : all_custodies().resource()) {
if (custody->is_deleted())
continue;
if (custody->is_mounted_on())
continue;
if (custody->parent() == parent && custody->name() == name)
return custody;
}
return nullptr;
}
Retained<Custody> Custody::get_or_create(Custody* parent, const String& name, Inode& inode)
{
if (RetainPtr<Custody> cached_custody = get_if_cached(parent, name)) {
if (&cached_custody->inode() != &inode) {
dbgprintf("WTF! cached custody for name '%s' has inode=%s, new inode=%s\n",
name.characters(),
cached_custody->inode().identifier().to_string().characters(),
inode.identifier().to_string().characters());
}
ASSERT(&cached_custody->inode() == &inode);
return *cached_custody;
}
return create(parent, name, inode);
}
Custody::Custody(Custody* parent, const String& name, Inode& inode)
: m_parent(parent)
, m_name(name)
, m_inode(inode)
{
LOCKER(all_custodies().lock());
all_custodies().resource().set(this);
}
Custody::~Custody()
{
LOCKER(all_custodies().lock());
all_custodies().resource().remove(this);
}
String Custody::absolute_path() const
{
Vector<const Custody*, 32> custody_chain;
for (auto* 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().characters());
}
return builder.to_string();
}
void Custody::did_delete(Badge<VFS>)
{
m_deleted = true;
}
void Custody::did_mount_on(Badge<VFS>)
{
m_mounted_on = true;
}
void Custody::did_rename(Badge<VFS>, const String& name)
{
m_name = name;
}