transmission/qt/FaviconCache.cc

212 lines
5.2 KiB
C++

// This file Copyright © 2012-2022 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#include <array>
#include <QDir>
#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QNetworkRequest>
#include <QStandardPaths>
#include "FaviconCache.h"
/***
****
***/
FaviconCache::FaviconCache()
: nam_(new QNetworkAccessManager(this))
{
connect(nam_, &QNetworkAccessManager::finished, this, &FaviconCache::onRequestFinished);
}
/***
****
***/
namespace
{
QPixmap scale(QPixmap const& pixmap)
{
return pixmap.scaled(FaviconCache::getIconSize(), Qt::KeepAspectRatio, Qt::SmoothTransformation);
}
QString getCacheDir()
{
auto const base = QStandardPaths::writableLocation(QStandardPaths::CacheLocation);
return QDir(base).absoluteFilePath(QStringLiteral("favicons"));
}
QString getScrapedFile()
{
auto const base = QStandardPaths::writableLocation(QStandardPaths::CacheLocation);
return QDir(base).absoluteFilePath(QStringLiteral("favicons-scraped.txt"));
}
void markSiteAsScraped(QString const& sitename)
{
auto skip_file = QFile(getScrapedFile());
if (skip_file.open(QIODevice::WriteOnly | QIODevice::Text | QIODevice::Append))
{
skip_file.write(sitename.toUtf8());
skip_file.write("\n");
}
}
} // namespace
void FaviconCache::ensureCacheDirHasBeenScanned()
{
static bool has_been_scanned = false;
if (has_been_scanned)
{
return;
}
has_been_scanned = true;
// remember which hosts we've asked for a favicon so that we
// don't re-ask them every time we start a new session
if (auto skip_file = QFile(getScrapedFile()); skip_file.open(QIODevice::ReadOnly | QIODevice::Text))
{
while (!skip_file.atEnd())
{
auto const sitename = QString::fromUtf8(skip_file.readLine()).trimmed();
pixmaps_.try_emplace(sitename);
}
}
// load the cached favicons
auto cache_dir = QDir(getCacheDir());
cache_dir.mkpath(cache_dir.absolutePath());
for (auto const& sitename : cache_dir.entryList(QDir::Files | QDir::Readable))
{
QPixmap const pixmap(cache_dir.absoluteFilePath(sitename));
if (!pixmap.isNull())
{
pixmaps_[sitename] = scale(pixmap);
}
}
}
/***
****
***/
QString FaviconCache::getDisplayName(QString const& sitename)
{
auto name = sitename;
if (!name.isEmpty())
{
name.front() = name.front().toTitleCase();
}
return name;
}
QSize FaviconCache::getIconSize()
{
return { 16, 16 };
}
QPixmap FaviconCache::find(QString const& sitename)
{
ensureCacheDirHasBeenScanned();
return pixmaps_[sitename];
}
void FaviconCache::add(QString const& sitename, QString const& url_str)
{
ensureCacheDirHasBeenScanned();
// Try to download a favicon if we don't have one.
// Add a placeholder to prevent repeat downloads.
if (auto const already_had_it = !pixmaps_.try_emplace(sitename).second; already_had_it)
{
return;
}
markSiteAsScraped(sitename);
auto const scrape = [this, sitename](auto const host)
{
auto const schemes = std::array<QString, 2>{
QStringLiteral("http"),
QStringLiteral("https"),
};
auto const suffixes = std::array<QString, 5>{
QStringLiteral("gif"), //
QStringLiteral("ico"), //
QStringLiteral("jpg"), //
QStringLiteral("png"), //
QStringLiteral("svg"), //
};
for (auto const& scheme : schemes)
{
for (auto const& suffix : suffixes)
{
auto const path = QStringLiteral("%1://%2/favicon.%3").arg(scheme).arg(host).arg(suffix);
auto request = QNetworkRequest(path);
request.setAttribute(QNetworkRequest::UserMax, sitename);
nam_->get(request);
}
}
};
// scrape tracker.domain.com
auto const host = QUrl(url_str).host();
scrape(host);
if (auto const idx = host.indexOf(sitename); idx != -1)
{
// scrape domain.com
auto const root = host.mid(idx);
if (root != host)
{
scrape(root);
}
// scrape www.domain.com
if (auto const www = QStringLiteral("www.") + root; www != host)
{
scrape(www);
}
}
}
void FaviconCache::onRequestFinished(QNetworkReply* reply)
{
auto const content = reply->readAll();
auto pixmap = QPixmap{};
if (reply->error() == QNetworkReply::NoError)
{
pixmap.loadFromData(content);
}
if (!pixmap.isNull())
{
auto sitename = reply->request().attribute(QNetworkRequest::UserMax).toString();
// save it in memory...
pixmaps_[sitename] = scale(pixmap);
// save it on disk...
QDir const cache_dir(getCacheDir());
cache_dir.mkpath(cache_dir.absolutePath());
QFile file(cache_dir.absoluteFilePath(sitename));
file.open(QIODevice::WriteOnly);
file.write(content);
file.close();
// notify listeners
emit pixmapReady(sitename);
}
reply->deleteLater();
}