src/base/asyncfilestorage.cpp

   1 /*
   2  * Bittorrent Client using Qt and libtorrent.
   3  * Copyright (C) 2017-2024  Vladimir Golovnev <glassez@yandex.ru>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version 2
   8  * of the License, or (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  18  *
  19  * In addition, as a special exception, the copyright holders give permission to
  20  * link this program with the OpenSSL project's "OpenSSL" library (or with
  21  * modified versions of it that use the same license as the "OpenSSL" library),
  22  * and distribute the linked executables. You must obey the GNU General Public
  23  * License in all respects for all of the code used other than "OpenSSL".  If you
  24  * modify file(s), you may extend this exception to your version of the file(s),
  25  * but you are not obligated to do so. If you do not wish to do so, delete this
  26  * exception statement from your version.
  27  */
  28
  29 #include "asyncfilestorage.h"
  30
  31 #include <QDebug>
  32 #include <QMetaObject>
  33
  34 #include "base/utils/fs.h"
  35 #include "base/utils/io.h"
  36
  37 QHash<Path, std::weak_ptr<QFile>> AsyncFileStorage::m_reservedPaths;
  38 QReadWriteLock AsyncFileStorage::m_reservedPathsLock;
  39
  40 AsyncFileStorage::AsyncFileStorage(const Path &storageFolderPath, QObject *parent)
  41     : QObject(parent)
  42     , m_storageDir(storageFolderPath)
  43 {
  44     Q_ASSERT(m_storageDir.isAbsolute());
  45
  46     const Path lockFilePath = m_storageDir / Path(u"storage.lock"_s);
  47
  48     {
  49         const QReadLocker readLocker {&m_reservedPathsLock};
  50         m_lockFile = m_reservedPaths.value(lockFilePath).lock();
  51     }
  52
  53     if (!m_lockFile)
  54     {
  55         const QWriteLocker writeLocker {&m_reservedPathsLock};
  56         if (std::weak_ptr<QFile> &lockFile = m_reservedPaths[lockFilePath]; lockFile.expired()) [[likely]]
  57         {
  58             if (!Utils::Fs::mkpath(m_storageDir))
  59                 throw AsyncFileStorageError(tr("Could not create directory '%1'.").arg(m_storageDir.toString()));
  60
  61             auto lockFileDeleter = [](QFile *file)
  62             {
  63                 file->close();
  64                 file->remove();
  65                 delete file;
  66             };
  67             m_lockFile = std::shared_ptr<QFile>(new QFile(lockFilePath.data()), std::move(lockFileDeleter));
  68
  69             // TODO: This folder locking approach does not work for UNIX systems. Implement it.
  70             if (!m_lockFile->open(QFile::WriteOnly))
  71                 throw AsyncFileStorageError(m_lockFile->errorString());
  72
  73             lockFile = m_lockFile;
  74         }
  75         else
  76         {
  77             m_lockFile = lockFile.lock();
  78         }
  79     }
  80 }
  81
  82 AsyncFileStorage::~AsyncFileStorage() = default;
  83
  84 void AsyncFileStorage::store(const Path &filePath, const QByteArray &data)
  85 {
  86     QMetaObject::invokeMethod(this, [this, data, filePath] { store_impl(filePath, data); }, Qt::QueuedConnection);
  87 }
  88
  89 Path AsyncFileStorage::storageDir() const
  90 {
  91     return m_storageDir;
  92 }
  93
  94 void AsyncFileStorage::store_impl(const Path &fileName, const QByteArray &data)
  95 {
  96     const Path filePath = m_storageDir / fileName;
  97     qDebug() << "AsyncFileStorage: Saving data to" << filePath.toString();
  98
  99     const nonstd::expected<void, QString> result = Utils::IO::saveToFile(filePath, data);
 100     if (!result)
 101     {
 102         qDebug() << "AsyncFileStorage: Failed to save data";
 103         emit failed(filePath, result.error());
 104     }
 105 }