annotate base/TempDirectory.cpp @ 537:3cc4b7cd2aa5

* Merge from one-fftdataserver-per-fftmodel branch.  This bit of
reworking (which is not described very accurately by the title of
the branch) turns the MatrixFile object into something that either
reads or writes, but not both, and separates the FFT file cache
reader and writer implementations separately.  This allows the
FFT data server to have a single thread owning writers and one reader
per "customer" thread, and for all locking to be vastly simplified
and concentrated in the data server alone (because none of the
classes it makes use of is used in more than one thread at a time).
The result is faster and more trustworthy code.

/* -*- 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::getContainingPath()
{
    QMutexLocker locker(&m_mutex);
    
    QSettings settings;
    settings.beginGroup("TempDirectory");
    QString svDirParent = settings.value("create-in", "$HOME").toString();
    settings.endGroup();

#ifdef Q_OS_WIN32
    char *homedrive = getenv("HOMEDRIVE");
    char *homepath = getenv("HOMEPATH");
    if (homedrive && homepath) {
        svDirParent.replace("$HOME", QString("%1%2").arg(homedrive).arg(homepath));
    } else {
        svDirParent.replace("$HOME", QDir::home().absolutePath());
    }
#else
    svDirParent.replace("$HOME", QDir::home().absolutePath());
#endif

    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 svDir;
}    

QString
TempDirectory::getPath()
{
    if (m_tmpdir != "") return m_tmpdir;

    return createTempDirectoryIn(getContainingPath());
}

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;
            }
        }
    }
}