Atmosphere/libraries/libstratosphere/include/stratosphere/ncm/ncm_rights_id_cache.hpp
2022-03-22 14:02:14 -07:00

90 lines
3.3 KiB
C++

/*
* Copyright (c) Atmosphère-NX
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <stratosphere/os.hpp>
#include <stratosphere/ncm/ncm_rights_id.hpp>
#include <stratosphere/ncm/ncm_content_id.hpp>
namespace ams::ncm {
class RightsIdCache {
NON_COPYABLE(RightsIdCache);
NON_MOVEABLE(RightsIdCache);
private:
static constexpr size_t MaxEntries = 0x80;
private:
struct Entry {
public:
util::Uuid uuid;
ncm::RightsId rights_id;
u64 last_accessed;
};
private:
Entry m_entries[MaxEntries];
u64 m_counter;
os::SdkMutex m_mutex;
public:
RightsIdCache() : m_entries(), m_counter(2), m_mutex() {
this->Invalidate();
}
void Invalidate() {
m_counter = 2;
for (size_t i = 0; i < MaxEntries; i++) {
m_entries[i].last_accessed = 1;
}
}
void Store(ContentId content_id, ncm::RightsId rights_id) {
std::scoped_lock lk(m_mutex);
Entry *eviction_candidate = std::addressof(m_entries[0]);
/* Find a suitable existing entry to store our new one at. */
for (size_t i = 1; i < MaxEntries; i++) {
Entry *entry = std::addressof(m_entries[i]);
/* Change eviction candidates if the uuid already matches ours, or if the uuid doesn't already match and the last_accessed count is lower */
if (content_id == entry->uuid || (content_id != eviction_candidate->uuid && entry->last_accessed < eviction_candidate->last_accessed)) {
eviction_candidate = entry;
}
}
/* Update the cache. */
eviction_candidate->uuid = content_id.uuid;
eviction_candidate->rights_id = rights_id;
eviction_candidate->last_accessed = m_counter++;
}
bool Find(ncm::RightsId *out_rights_id, ContentId content_id) {
std::scoped_lock lk(m_mutex);
/* Attempt to locate the content id in the cache. */
for (size_t i = 0; i < MaxEntries; i++) {
Entry *entry = std::addressof(m_entries[i]);
if (entry->last_accessed != 1 && content_id == entry->uuid) {
entry->last_accessed = m_counter;
m_counter++;
*out_rights_id = entry->rights_id;
return true;
}
}
return false;
}
};
}