annotate base/TempDirectory.cpp @ 1376:d9511f9e04d7 dev/refactor-piper-related

Introduce some POD structs for describing an external server application and the desired libraries to load from it, and disambiguating between empty list request and invalid list request. This allows for overriding PiperVampPluginFactory behaviour for using a PluginScan to populate the list request.

/* -*- 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 "ResourceFinder.h"
#include "system/System.h"
#include "Exceptions.h"

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

#include <iostream>
#include <cassert>

#include <time.h>

TempDirectory *
TempDirectory::m_instance = new TempDirectory;

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

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

TempDirectory::~TempDirectory()
{
    SVDEBUG << "TempDirectory::~TempDirectory" << 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();

    QString svDir = ResourceFinder().getUserResourcePrefix();
    if (svDirParent != "$HOME") {
        //!!! iffy
        svDir.replace(QDir::home().absolutePath(), svDirParent);
    }

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

    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 = (unsigned int)(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()) {
                cerr << "WARNING: TempDirectory::cleanup: "
                          << "Failed to unlink file \""
                          << fi.absoluteFilePath() << "\""
                          << endl;
            }
        }
    }

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

        QDir subdir(dirpath, "*.pid", QDir::Name, QDir::Files);

        if (subdir.count() == 0) {
            cerr << "INFO: Found temporary directory with no .pid file in it!\n(directory=\""
                      << dirpath << "\").  Removing it..." << endl;
            cleanupDirectory(dirpath);
            cerr << "...done." << endl;
            continue;
        }

        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) {
                cerr << "INFO: Found abandoned temporary directory from "
                          << "a previous, defunct process\n(pid=" << pid
                          << ", directory=\""
                          << dirpath
                          << "\").  Removing it..." << endl;
                cleanupDirectory(dirpath);
                cerr << "...done." << endl;
                break;
            }
        }
    }
}