File indexing completed on 2024-04-28 15:39:58

 /* SPDX-FileCopyrightText: 2018 Johannes Zarl-Zierl <johannes@zarl-zierl.at>
    SPDX-FileCopyrightText: 2007-2010 Tuomas Suutari <thsuut@utu.fi>
 
    SPDX-License-Identifier: GPL-2.0-or-later
 */
 
 #include "MD5.h"
 
 #include <kpabase/FileName.h>
 
 #include <QCryptographicHash>
 #include <QFile>
 #include <QHash>
 #include <QIODevice>
 #include <QMutex>
 
 static QMutex s_MD5CacheMutex;
 static QHash<DB::FileName, DB::MD5> s_MD5Cache;
 
 DB::MD5::MD5()
     : m_isNull(true)
     , m_v0(0)
     , m_v1(0)
 {
 }
 
 DB::MD5::MD5(const QString &md5str)
     : m_isNull(md5str.isEmpty())
     , m_v0(md5str.leftRef(16).toULongLong(nullptr, 16))
     , m_v1(md5str.midRef(16, 16).toULongLong(nullptr, 16))
 {
 }
 
 bool DB::MD5::isNull() const
 {
     return m_isNull;
 }
 
 DB::MD5 &DB::MD5::operator=(const QString &md5str)
 {
     if (md5str.isEmpty()) {
         m_isNull = true;
     } else {
         m_isNull = false;
         m_v0 = md5str.leftRef(16).toULongLong(nullptr, 16);
         m_v1 = md5str.midRef(16, 16).toULongLong(nullptr, 16);
     }
     return *this;
 }
 
 QString DB::MD5::toHexString() const
 {
     QString res;
     static QChar ZERO(QChar::fromLatin1('0'));
     if (!isNull()) {
         res += QString::number(m_v0, 16).rightJustified(16, ZERO);
         res += QString::number(m_v1, 16).rightJustified(16, ZERO);
     }
     return res;
 }
 
 bool DB::MD5::operator==(const DB::MD5 &other) const
 {
     if (isNull() || other.isNull())
         return isNull() == other.isNull();
 
     return (m_v0 == other.m_v0 && m_v1 == other.m_v1);
 }
 
 bool DB::MD5::operator!=(const DB::MD5 &other) const
 {
     return !(*this == other);
 }
 
 bool DB::MD5::operator<(const DB::MD5 &other) const
 {
     if (isNull() || other.isNull())
         return isNull() && !other.isNull();
 
     return (m_v0 < other.m_v0 || (m_v0 == other.m_v0 && (m_v1 < other.m_v1)));
 }
 
 void DB::MD5::resetMD5Cache()
 {
     QMutexLocker locker(&s_MD5CacheMutex);
     s_MD5Cache.clear();
 }
 
 namespace
 {
 // Determined experimentally to yield best results (on Seagate 2TB 2.5" disk,
 // 5400 RPM).  Performance is very similar at 524288.  Above that, performance
 // was significantly worse.  Below that, performance also deteriorated.
 // This assumes use of one image scout thread (see DB/ImageScout.cpp).  Without
 // a scout thread, performance was about 10-15% worse.
 constexpr int MD5_BUFFER_SIZE = 262144;
 }
 
 DB::MD5 DB::MD5Sum(const DB::FileName &fileName)
 {
     QMutexLocker locker(&s_MD5CacheMutex);
     if (s_MD5Cache.contains(fileName)) {
         return s_MD5Cache[fileName];
     }
     locker.unlock();
     // It's possible that the checksum will be added between now
     // and when we add it, but as long as the file contents don't change
     // during that interval, the checksums will match.
     // Holding the lock while the checksum is being computed will
     // defeat the whole purpose.
     DB::MD5 checksum;
     QFile file(fileName.absolute());
     if (file.open(QIODevice::ReadOnly)) {
         QCryptographicHash md5calculator(QCryptographicHash::Md5);
         while (!file.atEnd()) {
             QByteArray md5Buffer(file.read(MD5_BUFFER_SIZE));
             md5calculator.addData(md5Buffer);
         }
         file.close();
         checksum = DB::MD5(QString::fromLatin1(md5calculator.result().toHex()));
     }
     locker.relock();
     s_MD5Cache[fileName] = checksum;
     return checksum;
 }
 
 void DB::PreloadMD5Sum(const DB::FileName &fileName)
 {
     (void)MD5Sum(fileName);
 }