pollymc/logic/net/HttpMetaCache.h

#pragma once
#include <QString>
#include <QSharedPointer>
#include <QMap>
#include <qtimer.h>

struct MetaEntry
{
	QString base;
	QString path;
	QString md5sum;
	QString etag;
	qint64 last_changed_timestamp = 0;
	bool stale = true;
	QString getFullPath();
};

typedef std::shared_ptr<MetaEntry> MetaEntryPtr;

class HttpMetaCache : public QObject
{
	Q_OBJECT
public:
	// supply path to the cache index file
	HttpMetaCache(QString path);
	~HttpMetaCache();

	// get the entry solely from the cache
	// you probably don't want this, unless you have some specific caching needs.
	MetaEntryPtr getEntry(QString base, QString resource_path);

	// get the entry from cache and verify that it isn't stale (within reason)
	MetaEntryPtr resolveEntry(QString base, QString resource_path,
							  QString expected_etag = QString());

	// add a previously resolved stale entry
	bool updateEntry(MetaEntryPtr stale_entry);

	void addBase(QString base, QString base_root);

	// (re)start a timer that calls SaveNow later.
	void SaveEventually();
	void Load();
	QString getBasePath(QString base);
public
slots:
	void SaveNow();

private:
	// create a new stale entry, given the parameters
	MetaEntryPtr staleEntry(QString base, QString resource_path);
	struct EntryMap
	{
		QString base_path;
		QMap<QString, MetaEntryPtr> entry_list;
	};
	QMap<QString, EntryMap> m_entries;
	QString m_index_file;
	QTimer saveBatchingTimer;
};