Chris@465: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@465: 
Chris@465: /*
Chris@465:     Sonic Visualiser
Chris@465:     An audio file viewer and annotation editor.
Chris@465:     Centre for Digital Music, Queen Mary, University of London.
Chris@465:     This file copyright 2008 QMUL.
Chris@465:     
Chris@465:     This program is free software; you can redistribute it and/or
Chris@465:     modify it under the terms of the GNU General Public License as
Chris@465:     published by the Free Software Foundation; either version 2 of the
Chris@465:     License, or (at your option) any later version.  See the file
Chris@465:     COPYING included with this distribution for more information.
Chris@465: */
Chris@465: 
Chris@465: #include "CachedFile.h"
Chris@465: 
Chris@465: #include "base/TempDirectory.h"
Chris@465: #include "base/ProgressReporter.h"
Chris@465: #include "base/Exceptions.h"
Chris@465: 
Chris@465: #include <QFileInfo>
Chris@465: #include <QSettings>
Chris@465: #include <QVariant>
Chris@465: #include <QMap>
Chris@465: #include <QDir>
Chris@465: #include <QCryptographicHash>
Chris@465: 
Chris@465: QString
Chris@465: CachedFile::getLocalFilenameFor(QUrl url)
Chris@465: {
Chris@465:     QDir dir(getCacheDirectory());
Chris@465: 
Chris@465:     QString filename =
Chris@465:         QString::fromLocal8Bit
Chris@465:         (QCryptographicHash::hash(url.toString().toLocal8Bit(),
Chris@465:                                   QCryptographicHash::Sha1).toHex());
Chris@465: 
Chris@465:     return dir.filePath(filename);
Chris@465: }
Chris@465: 
Chris@465: QString
Chris@465: CachedFile::getCacheDirectory()
Chris@465: {
Chris@465:     QDir dir = TempDirectory::getInstance()->getContainingPath();
Chris@465: 
Chris@465:     QString cacheDirName("cache");
Chris@465: 
Chris@465:     QFileInfo fi(dir.filePath(cacheDirName));
Chris@465: 
Chris@465:     if ((fi.exists() && !fi.isDir()) ||
Chris@465:         (!fi.exists() && !dir.mkdir(cacheDirName))) {
Chris@465: 
Chris@465:         throw DirectoryCreationFailed(fi.filePath());
Chris@465:     }
Chris@465: 
Chris@465:     return fi.filePath();
Chris@465: }
Chris@465: 
Chris@465: CachedFile::CachedFile(QUrl url, ProgressReporter *reporter) :
Chris@465:     m_url(url),
Chris@465:     m_localFilename(getLocalFilenameFor(url)),
Chris@465:     m_ok(false)
Chris@465: {
Chris@465:     refresh();
Chris@465: }
Chris@465: 
Chris@465: bool
Chris@465: CachedFile::isOK() const
Chris@465: {
Chris@465:     return m_ok;
Chris@465: }
Chris@465: 
Chris@465: QString
Chris@465: CachedFile::getLocalFilename() const
Chris@465: {
Chris@465:     return m_localFilename;
Chris@465: }
Chris@465: 
Chris@465: void
Chris@465: CachedFile::refresh()
Chris@465: {
Chris@465:     //!!! n.b. obvious race condition here if different CachedFile
Chris@465:     // objects for same url used in more than one thread -- need to
Chris@465:     // lock appropriately.  also consider race condition between
Chris@465:     // separate instances of the program
Chris@465: 
Chris@465:     if (!QFileInfo(m_localFilename).exists()) {
Chris@465:         updateLastRetrieval(false); // empirically!
Chris@465:     }
Chris@465: 
Chris@465:     QDateTime lastRetrieval = getLastRetrieval();
Chris@465: 
Chris@465:     if (lastRetrieval.isValid()) {
Chris@465:         // this will not be the case if the file is missing, after
Chris@465:         // updateLastRetrieval(false) was called above
Chris@465:         m_ok = true;
Chris@465:         if (lastRetrieval.addDays(2) < QDateTime::currentDateTime()) { //!!!
Chris@465:             // doesn't matter if retrieval fails -- we just don't
Chris@465:             // update the last retrieval time
Chris@465: 
Chris@465:             //!!! but we do want an additional last-attempted
Chris@465:             // timestamp so as to ensure we aren't retrying the
Chris@465:             // retrieval every single time if it isn't working
Chris@465: 
Chris@465:             if (retrieve()) {
Chris@465:                 updateLastRetrieval(true);
Chris@465:             }
Chris@465:         }
Chris@465:     } else {
Chris@465:         // there is no acceptable file
Chris@465:         if (retrieve()) {
Chris@465:             m_ok = true;
Chris@465:             updateLastRetrieval(true);
Chris@465:         } else {
Chris@465:             // again, we don't need to do anything here -- the last
Chris@465:             // retrieval timestamp is already invalid
Chris@465:         }
Chris@465:     }
Chris@465: }
Chris@465: 
Chris@465: bool
Chris@465: CachedFile::retrieve()
Chris@465: {
Chris@465:     //!!! need to work by retrieving the file to another name, and
Chris@465:     //!!! then "atomically" moving it to its proper place (I'm not
Chris@465:     //!!! sure we can do an atomic move to replace an existing file
Chris@465:     //!!! using Qt classes, but a plain delete then copy is probably
Chris@465:     //!!! good enough)
Chris@465: 
Chris@465: 
Chris@465: 
Chris@465: 
Chris@465: }
Chris@465: 
Chris@465: QDateTime
Chris@465: CachedFile::getLastRetrieval()
Chris@465: {
Chris@465:     QSettings settings;
Chris@465:     settings.beginGroup("FileCache");
Chris@465: 
Chris@465:     QString key("last-retrieval-times");
Chris@465: 
Chris@465:     QMap<QString, QVariant> timeMap = settings.value(key).toMap();
Chris@465:     QDateTime lastTime = timeMap[m_localFilename].toDateTime();
Chris@465: 
Chris@465:     settings.endGroup();
Chris@465:     return lastTime;
Chris@465: }
Chris@465: 
Chris@465: void
Chris@465: CachedFile::updateLastRetrieval(bool successful)
Chris@465: {
Chris@465:     //!!! note !successful does not mean "we failed to update the
Chris@465:     //!!! file" (and so it remains the same as before); it means "the
Chris@465:     //!!! file is not there at all"
Chris@465:     
Chris@465:     QSettings settings;
Chris@465:     settings.beginGroup("FileCache");
Chris@465: 
Chris@465:     QString key("last-retrieval-times");
Chris@465: 
Chris@465:     QMap<QString, QVariant> timeMap = settings.value(key).toMap();
Chris@465: 
Chris@465:     QDateTime dt;
Chris@465:     if (successful) dt = QDateTime::currentDateTime();
Chris@465: 
Chris@465:     timeMap[m_localFilename] = dt;
Chris@465:     settings.setValue(key, timeMap);
Chris@465: 
Chris@465:     settings.endGroup();
Chris@465: }
Chris@465: 
Chris@465: