pollymc/launcher/net/HttpMetaCache.h
flow 6be59b53f1
feat: add eternal cache entries
Those are entries that don't get stale over time, so we don't invalidate
them if they 'expire'.

Signed-off-by: flow <flowlnlnln@gmail.com>
2022-08-21 13:47:49 -03:00

141 lines
4.5 KiB
C++

// SPDX-License-Identifier: GPL-3.0-only
/*
* PolyMC - Minecraft Launcher
* Copyright (c) 2022 flowln <flowlnlnln@gmail.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 3.
*
* This program is distributed in the hope that 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 <https://www.gnu.org/licenses/>.
*
* This file incorporates work covered by the following copyright and
* permission notice:
*
* Copyright 2013-2021 MultiMC Contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <QMap>
#include <QString>
#include <QTimer>
#include <memory>
class HttpMetaCache;
class MetaEntry {
friend class HttpMetaCache;
protected:
MetaEntry() = default;
public:
auto isStale() -> bool { return stale; }
void setStale(bool stale) { this->stale = stale; }
auto getFullPath() -> QString;
auto getRemoteChangedTimestamp() -> QString { return remote_changed_timestamp; }
void setRemoteChangedTimestamp(QString remote_changed_timestamp) { this->remote_changed_timestamp = remote_changed_timestamp; }
void setLocalChangedTimestamp(qint64 timestamp) { local_changed_timestamp = timestamp; }
auto getETag() -> QString { return etag; }
void setETag(QString etag) { this->etag = etag; }
auto getMD5Sum() -> QString { return md5sum; }
void setMD5Sum(QString md5sum) { this->md5sum = md5sum; }
/* Whether the entry expires after some time (false) or not (true). */
void makeEternal(bool eternal) { is_eternal = eternal; }
[[nodiscard]] bool isEternal() const { return is_eternal; }
auto getCurrentAge() -> qint64 { return current_age; }
void setCurrentAge(qint64 age) { current_age = age; }
auto getMaximumAge() -> qint64 { return max_age; }
void setMaximumAge(qint64 age) { max_age = age; }
bool isExpired(qint64 offset) { return !is_eternal && (current_age >= max_age - offset); };
protected:
QString baseId;
QString basePath;
QString relativePath;
QString md5sum;
QString etag;
qint64 local_changed_timestamp = 0;
QString remote_changed_timestamp; // QString for now, RFC 2822 encoded time
qint64 current_age = 0;
qint64 max_age = 0;
bool is_eternal = false;
bool stale = true;
};
using MetaEntryPtr = std::shared_ptr<MetaEntry>;
class HttpMetaCache : public QObject {
Q_OBJECT
public:
// supply path to the cache index file
HttpMetaCache(QString path = QString());
~HttpMetaCache() override;
// get the entry solely from the cache
// you probably don't want this, unless you have some specific caching needs.
auto getEntry(QString base, QString resource_path) -> MetaEntryPtr;
// get the entry from cache and verify that it isn't stale (within reason)
auto resolveEntry(QString base, QString resource_path, QString expected_etag = QString()) -> MetaEntryPtr;
// add a previously resolved stale entry
auto updateEntry(MetaEntryPtr stale_entry) -> bool;
// evict selected entry from cache
auto evictEntry(MetaEntryPtr entry) -> bool;
void addBase(QString base, QString base_root);
// (re)start a timer that calls SaveNow later.
void SaveEventually();
void Load();
auto getBasePath(QString base) -> QString;
public slots:
void SaveNow();
private:
// create a new stale entry, given the parameters
auto staleEntry(QString base, QString resource_path) -> MetaEntryPtr;
struct EntryMap {
QString base_path;
QMap<QString, MetaEntryPtr> entry_list;
};
QMap<QString, EntryMap> m_entries;
QString m_index_file;
QTimer saveBatchingTimer;
};