annotate base/ResourceFinder.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 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.
*/

/*
   This is a modified version of a source file from the 
   Rosegarden MIDI and audio sequencer and notation editor.
   This file copyright 2005-2011 Chris Cannam and the Rosegarden
   development team.
*/

#include "ResourceFinder.h"

#include <QDir>
#include <QFileInfo>
#include <QStringList>
#include <QProcess>
#include <QCoreApplication>

#if QT_VERSION >= 0x050000
#include <QStandardPaths>
#endif

#include <cstdlib>
#include <iostream>
#include <stdexcept>

/**
   Resource files may be found in three places:

   * Bundled into the application as Qt4 resources.  These may be
     opened using Qt classes such as QFile, with "fake" file paths
     starting with a colon.  For example ":icons/fileopen.png".

   * Installed with the package, or in the user's equivalent home
     directory location.  For example,

     - on Linux, in /usr/share/<appname> or /usr/local/share/<appname>
     - on Linux, in $HOME/.local/share/<appname>

     - on OS/X, in /Library/Application Support/<appname>
     - on OS/X, in $HOME/Library/Application Support/<appname>

     - on Windows, in %ProgramFiles%/<company>/<appname>
     - on Windows, in (where?) something from http://msdn.microsoft.com/en-us/library/dd378457%28v=vs.85%29.aspx ?

   These locations are searched in reverse order (user-installed
   copies take priority over system-installed copies take priority
   over bundled copies).  Also, /usr/local takes priority over /usr.
*/

QStringList
ResourceFinder::getSystemResourcePrefixList()
{
    // returned in order of priority

    QStringList list;

#ifdef Q_OS_WIN32
    char *programFiles = getenv("ProgramFiles");
    if (programFiles && programFiles[0]) {
        list << QString("%1/%2/%3")
            .arg(programFiles)
            .arg(qApp->organizationName())
            .arg(qApp->applicationName());
    } else {
        list << QString("C:/Program Files/%1/%2")
            .arg(qApp->organizationName())
            .arg(qApp->applicationName());
    }
#else
#ifdef Q_OS_MAC
    list << QString("/Library/Application Support/%1")
        .arg(qApp->applicationName());
#else
    list << QString("/usr/local/share/%1")
        .arg(qApp->applicationName());
    list << QString("/usr/share/%1")
        .arg(qApp->applicationName());
#endif
#endif    

    return list;
}

static QString
getOldStyleUserResourcePrefix()
{
#ifdef Q_OS_WIN32
    // This is awkward and does not work correctly for non-ASCII home
    // directory names, hence getNewStyleUserResourcePrefix() below
    char *homedrive = getenv("HOMEDRIVE");
    char *homepath = getenv("HOMEPATH");
    QString home;
    if (homedrive && homepath) {
        home = QString("%1%2").arg(homedrive).arg(homepath);
    } else {
        home = QDir::home().absolutePath();
    }
    if (home == "") return "";
    return QString("%1/.%2").arg(home).arg(qApp->applicationName()); //!!! wrong
#else
    char *home = getenv("HOME");
    if (!home || !home[0]) return "";
#ifdef Q_OS_MAC
    return QString("%1/Library/Application Support/%2")
        .arg(home)
        .arg(qApp->applicationName());
#else
    return QString("%1/.local/share/%2")
        .arg(home)
        .arg(qApp->applicationName());
#endif
#endif
}

static QString
getNewStyleUserResourcePrefix()
{
    if (qApp->applicationName() == "") {
        cerr << "ERROR: Can't use ResourceFinder before setting application name" << endl;
        throw std::logic_error("Can't use ResourceFinder before setting application name");
    }

#if QT_VERSION >= 0x050000
    // This is expected to be much more reliable than
    // getOldStyleUserResourcePrefix(), but it returns a different
    // directory because it includes the organisation name (which is
    // fair enough). Hence migrateOldStyleResources() which moves
    // across any resources found in the old-style path the first time
    // we look for the new-style one
    return QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
#else
    return getOldStyleUserResourcePrefix();
#endif
}

static void
migrateOldStyleResources()
{
    QString oldPath = getOldStyleUserResourcePrefix();
    QString newPath = getNewStyleUserResourcePrefix();
    
    if (oldPath != newPath &&
        QDir(oldPath).exists() &&
        !QDir(newPath).exists()) {

        QDir d(oldPath);
        
        if (!d.mkpath(newPath)) {
            cerr << "WARNING: Failed to create new-style resource path \""
                 << newPath << "\" to migrate old resources to" << endl;
            return;
        }

        QDir target(newPath);

        bool success = true;

        QStringList entries
            (d.entryList(QDir::Dirs | QDir::Files | QDir::NoDotAndDotDot));

        foreach (QString entry, entries) {
            if (d.rename(entry, target.filePath(entry))) {
                cerr << "NOTE: Successfully moved resource \""
                     << entry << "\" from old resource path to new" << endl;
            } else {
                cerr << "WARNING: Failed to move old resource \""
                     << entry << "\" from old location \""
                     << oldPath << "\" to new location \""
                     << newPath << "\"" << endl;
                success = false;
            }
        }

        if (success) {
            if (!d.rmdir(oldPath)) {
                cerr << "WARNING: Failed to remove old resource path \""
                     << oldPath << "\" after migrating " << entries.size()
                     << " resource(s) to new path \"" << newPath
                     << "\" (directory not empty?)" << endl;
            } else {
                cerr << "NOTE: Successfully moved " << entries.size()
                     << " resource(s) from old resource "
                     << "path \"" << oldPath << "\" to new path \""
                     << newPath << "\"" << endl;
            }
        }
    }
}

QString
ResourceFinder::getUserResourcePrefix()
{
    migrateOldStyleResources();
    return getNewStyleUserResourcePrefix();
}

QStringList
ResourceFinder::getResourcePrefixList()
{
    // returned in order of priority

    QStringList list;

    QString user = getUserResourcePrefix();
    if (user != "") list << user;

    list << getSystemResourcePrefixList();

    list << ":"; // bundled resource location

    return list;
}

QString
ResourceFinder::getResourcePath(QString resourceCat, QString fileName)
{
    // We don't simply call getResourceDir here, because that returns
    // only the "installed file" location.  We also want to search the
    // bundled resources and user-saved files.

    QStringList prefixes = getResourcePrefixList();
    
    if (resourceCat != "") resourceCat = "/" + resourceCat;

    for (QStringList::const_iterator i = prefixes.begin();
         i != prefixes.end(); ++i) {
        
        QString prefix = *i;

        SVDEBUG << "ResourceFinder::getResourcePath: Looking up file \"" << fileName << "\" for category \"" << resourceCat << "\" in prefix \"" << prefix << "\"" << endl;

        QString path =
            QString("%1%2/%3").arg(prefix).arg(resourceCat).arg(fileName);
        if (QFileInfo(path).exists() && QFileInfo(path).isReadable()) {
            cerr << "Found it!" << endl;
            return path;
        }
    }

    return "";
}

QString
ResourceFinder::getResourceDir(QString resourceCat)
{
    // Returns only the "installed file" location

    QStringList prefixes = getSystemResourcePrefixList();
    
    if (resourceCat != "") resourceCat = "/" + resourceCat;

    for (QStringList::const_iterator i = prefixes.begin();
         i != prefixes.end(); ++i) {
        
        QString prefix = *i;
        QString path = QString("%1%2").arg(prefix).arg(resourceCat);
        if (QFileInfo(path).exists() &&
            QFileInfo(path).isDir() &&
            QFileInfo(path).isReadable()) {
            return path;
        }
    }

    return "";
}

QString
ResourceFinder::getResourceSavePath(QString resourceCat, QString fileName)
{
    QString dir = getResourceSaveDir(resourceCat);
    if (dir == "") return "";

    return dir + "/" + fileName;
}

QString
ResourceFinder::getResourceSaveDir(QString resourceCat)
{
    // Returns the "user" location

    QString user = getUserResourcePrefix();
    if (user == "") return "";

    if (resourceCat != "") resourceCat = "/" + resourceCat;

    QDir userDir(user);
    if (!userDir.exists()) {
        if (!userDir.mkpath(user)) {
            cerr << "ResourceFinder::getResourceSaveDir: ERROR: Failed to create user resource path \"" << user << "\"" << endl;
            return "";
        }
    }

    if (resourceCat != "") {
        QString save = QString("%1%2").arg(user).arg(resourceCat);
        QDir saveDir(save);
        if (!saveDir.exists()) {
            if (!saveDir.mkpath(save)) {
                cerr << "ResourceFinder::getResourceSaveDir: ERROR: Failed to create user resource path \"" << save << "\"" << endl;
                return "";
            }
        }
        return save;
    } else {
        return user;
    }
}

QStringList
ResourceFinder::getResourceFiles(QString resourceCat, QString fileExt)
{
    QStringList results;
    QStringList prefixes = getResourcePrefixList();

    QStringList filters;
    filters << QString("*.%1").arg(fileExt);

    for (QStringList::const_iterator i = prefixes.begin();
         i != prefixes.end(); ++i) {
        
        QString prefix = *i;
        QString path;

        if (resourceCat != "") {
            path = QString("%1/%2").arg(prefix).arg(resourceCat);
        } else {
            path = prefix;
        }
        
        QDir dir(path);
        if (!dir.exists()) continue;

        dir.setNameFilters(filters);
        QStringList entries = dir.entryList
            (QDir::Files | QDir::Readable, QDir::Name);
        
        for (QStringList::const_iterator j = entries.begin();
             j != entries.end(); ++j) {
            results << QString("%1/%2").arg(path).arg(*j);
        }
    }

    return results;
}

bool
ResourceFinder::unbundleResource(QString resourceCat, QString fileName)
{
    QString path = getResourcePath(resourceCat, fileName);
    
    if (!path.startsWith(':')) return true;

    // This is the lowest-priority alternative path for this
    // resource, so we know that there must be no installed copy.
    // Install one to the user location.
    SVDEBUG << "ResourceFinder::unbundleResource: File " << fileName << " is bundled, un-bundling it" << endl;
    QString target = getResourceSavePath(resourceCat, fileName);
    QFile file(path);
    if (!file.copy(target)) {
        cerr << "ResourceFinder::unbundleResource: ERROR: Failed to un-bundle resource file \"" << fileName << "\" to user location \"" << target << "\"" << endl;
        return false;
    }

    QFile chmod(target);
    chmod.setPermissions(QFile::ReadOwner |
                         QFile::ReadUser  | /* for potential platform-independence */
                         QFile::ReadGroup |
                         QFile::ReadOther |
                         QFile::WriteOwner|
                         QFile::WriteUser); /* for potential platform-independence */

    return true;
}