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transmission/qt/FaviconCache.h
Charles Kerr b156f55dca
refactor: use a vector for FavIcon cache keys (#1432)
* refactor: use a vector for FavIcon cache keys

Third of three PRs focused on small memory wins in transmission-qt.
This one saves 1-2 M off RES in my 15K torrent testbed. Not a major
improvement, but nice enough.

Previously we held the torrent's tracker keys in an unordered_set.
That container type is overkill for this field: the list is usually
short and almost never changes, so we don't need fast insertion time.
We can keep the same log N lookup by using a sorted vector and avoid
the excess container size & memory allocations of an unordered_set.
2020-09-08 08:58:14 -05:00

60 lines
1.3 KiB
C++

/*
* This file Copyright (C) 2012-2015 Mnemosyne LLC
*
* It may be used under the GNU GPL versions 2 or 3
* or any future license endorsed by Mnemosyne LLC.
*
*/
#pragma once
#include <unordered_map>
#include <vector>
#include <QObject>
#include <QPixmap>
#include <QString>
#include "Macros.h"
#include "Utils.h" // std::hash<QString>
class QNetworkAccessManager;
class QNetworkReply;
class QUrl;
class FaviconCache : public QObject
{
Q_OBJECT
TR_DISABLE_COPY_MOVE(FaviconCache)
public:
FaviconCache();
using Key = QString;
using Keys = std::vector<Key>;
// returns a cached pixmap, or a NULL pixmap if there's no match in the cache
QPixmap find(Key const& key);
static Key getKey(QString const& display_name);
// This will emit a signal when (if) the icon becomes ready.
Key add(QString const& url);
static QString getDisplayName(Key const& key);
static QSize getIconSize();
signals:
void pixmapReady(Key const& key);
private slots:
void onRequestFinished(QNetworkReply* reply);
private:
static Key getKey(QUrl const& url);
void ensureCacheDirHasBeenScanned();
QNetworkAccessManager* nam_ = {};
std::unordered_map<Key, QPixmap> pixmaps_;
std::unordered_map<QString, Key> keys_;
};