annotate base/TempDirectory.cpp @ 335:02d2ad95ea52 spectrogram-cache-rejig

* Get storage advice for each cache in an FFT data server.  Allows us to be
  more confident about the actual memory situation and cut over from memory
  to disc part way through an FFT calculation if necessary.  StorageAdviser
  is now a bit too optimistic though (it's too keen to allocate large numbers
  of small blocks in memory).

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2006 Chris Cannam.
    
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

#include "TempDirectory.h"
#include "system/System.h"
#include "Exceptions.h"

#include <QDir>
#include <QFile>
#include <QMutexLocker>
#include <QSettings>

#include <iostream>
#include <cassert>

TempDirectory *
TempDirectory::m_instance = new TempDirectory;

TempDirectory *
TempDirectory::getInstance()
{
    return m_instance;
}

TempDirectory::TempDirectory() :
    m_tmpdir("")
{
}

TempDirectory::~TempDirectory()
{
    std::cerr << "TempDirectory::~TempDirectory" << std::endl;

    cleanup();
}

void
TempDirectory::cleanup()
{
    cleanupDirectory("");
}

QString
TempDirectory::getPath()
{
    QMutexLocker locker(&m_mutex);
    
    if (m_tmpdir != "") return m_tmpdir;

    QSettings settings;
    settings.beginGroup("TempDirectory");
    QString svDirParent = settings.value("create-in", "$HOME").toString();
    settings.endGroup();

    svDirParent.replace("$HOME", QDir::home().absolutePath());

    QString svDirBase = ".sv1";
    QString svDir = QDir(svDirParent).filePath(svDirBase);
    if (!QFileInfo(svDir).exists()) {
        if (!QDir(svDirParent).mkdir(svDirBase)) {
            throw DirectoryCreationFailed(QString("%1 directory in %2")
                                          .arg(svDirBase).arg(svDirParent));
        }
    } else if (!QFileInfo(svDir).isDir()) {
        throw DirectoryCreationFailed(QString("%1/%2 is not a directory")
                                      .arg(svDirParent).arg(svDirBase));
    }

    cleanupAbandonedDirectories(svDir);

    return createTempDirectoryIn(svDir);
}

QString
TempDirectory::createTempDirectoryIn(QString dir)
{
    // Entered with mutex held.

    QDir tempDirBase(dir);

    // Generate a temporary directory.  Qt4.1 doesn't seem to be able
    // to do this for us, and mkdtemp is not standard.  This method is
    // based on the way glibc does mkdtemp.

    static QString chars =
        "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

    QString suffix;
    int padlen = 6, attempts = 100;
    unsigned int r = time(0) ^ getpid();

    for (int i = 0; i < padlen; ++i) {
        suffix += "X";
    }
    
    for (int j = 0; j < attempts; ++j) {

        unsigned int v = r;
        
        for (int i = 0; i < padlen; ++i) {
            suffix[i] = chars[v % 62];
            v /= 62;
        }

        QString candidate = QString("sv_%1").arg(suffix);

        if (tempDirBase.mkpath(candidate)) {
            m_tmpdir = tempDirBase.filePath(candidate);
            break;
        }

        r = r + 7777;
    }

    if (m_tmpdir == "") {
        throw DirectoryCreationFailed(QString("temporary subdirectory in %1")
                                      .arg(tempDirBase.canonicalPath()));
    }

    QString pidpath = QDir(m_tmpdir).filePath(QString("%1.pid").arg(getpid()));
    QFile pidfile(pidpath);

    if (!pidfile.open(QIODevice::WriteOnly)) {
        throw DirectoryCreationFailed(QString("pid file creation in %1")
                                      .arg(m_tmpdir));
    } else {
        pidfile.close();
    }

    return m_tmpdir;
}

QString
TempDirectory::getSubDirectoryPath(QString subdir)
{
    QString tmpdirpath = getPath();
    
    QMutexLocker locker(&m_mutex);

    QDir tmpdir(tmpdirpath);
    QFileInfo fi(tmpdir.filePath(subdir));

    if (!fi.exists()) {
        if (!tmpdir.mkdir(subdir)) {
            throw DirectoryCreationFailed(fi.filePath());
        } else {
            return fi.filePath();
        }
    } else if (fi.isDir()) {
        return fi.filePath();
    } else {
        throw DirectoryCreationFailed(fi.filePath());
    }
}

void
TempDirectory::cleanupDirectory(QString tmpdir)
{
    bool isRoot = false;

    if (tmpdir == "") {

        m_mutex.lock();

        isRoot = true;
        tmpdir = m_tmpdir;

        if (tmpdir == "") {
            m_mutex.unlock();
            return;
        }
    }

    QDir dir(tmpdir);
    dir.setFilter(QDir::Dirs | QDir::Files);

    for (unsigned int i = 0; i < dir.count(); ++i) {

        if (dir[i] == "." || dir[i] == "..") continue;
        QFileInfo fi(dir.filePath(dir[i]));

        if (fi.isDir()) {
            cleanupDirectory(fi.absoluteFilePath());
        } else {
            if (!QFile(fi.absoluteFilePath()).remove()) {
                std::cerr << "WARNING: TempDirectory::cleanup: "
                          << "Failed to unlink file \""
                          << fi.absoluteFilePath().toStdString() << "\""
                          << std::endl;
            }
        }
    }

    QString dirname = dir.dirName();
    if (dirname != "") {
        if (!dir.cdUp()) {
            std::cerr << "WARNING: TempDirectory::cleanup: "
                      << "Failed to cd to parent directory of "
                      << tmpdir.toStdString() << std::endl;
            return;
        }
        if (!dir.rmdir(dirname)) {
            std::cerr << "WARNING: TempDirectory::cleanup: "
                      << "Failed to remove directory "
                      << dirname.toStdString() << std::endl;
        } 
    }

    if (isRoot) {
        m_tmpdir = "";
        m_mutex.unlock();
    }
}

void
TempDirectory::cleanupAbandonedDirectories(QString svDir)
{
    QDir dir(svDir, "sv_*", QDir::Name, QDir::Dirs);

    for (unsigned int i = 0; i < dir.count(); ++i) {
        
        QDir subdir(dir.filePath(dir[i]), "*.pid", QDir::Name, QDir::Files);

        for (unsigned int j = 0; j < subdir.count(); ++j) {

            bool ok = false;
            int pid = QFileInfo(subdir[j]).baseName().toInt(&ok);
            if (!ok) continue;

            if (GetProcessStatus(pid) == ProcessNotRunning) {
                std::cerr << "INFO: Found abandoned temporary directory from "
                          << "a previous, defunct process\n(pid=" << pid
                          << ", directory=\""
                          << dir.filePath(dir[i]).toStdString()
                          << "\").  Removing it..." << std::endl;
                cleanupDirectory(dir.filePath(dir[i]));
                std::cerr << "...done." << std::endl;
                break;
            }
        }
    }
}