annotate base/HelperExecPath.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 2006-2016 Chris Cannam and QMUL.
    
    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 "HelperExecPath.h"

#include <QCoreApplication>
#include <QFile>
#include <QDir>
#include <QFileInfo>

QStringList
HelperExecPath::getTags()
{
    if (sizeof(void *) == 8) {
        if (m_type == NativeArchitectureOnly) {
            return { "64", "" };
        } else {
            return { "64", "", "32" };
        }
    } else {
        return { "", "32" };
    }
}

static bool
isGood(QString path)
{
    return QFile(path).exists() && QFileInfo(path).isExecutable();
}

QList<HelperExecPath::HelperExec>
HelperExecPath::getHelperExecutables(QString basename)
{
    QStringList dummy;
    return search(basename, dummy);
}

QString
HelperExecPath::getHelperExecutable(QString basename)
{
    auto execs = getHelperExecutables(basename);
    if (execs.empty()) return "";
    else return execs[0].executable;
}

QStringList
HelperExecPath::getHelperDirPaths()
{
    QStringList dirs;
    QString myDir = QCoreApplication::applicationDirPath();
    dirs.push_back(myDir + "/helpers");
    dirs.push_back(myDir);
    return dirs;
}

QStringList
HelperExecPath::getHelperCandidatePaths(QString basename)
{
    QStringList candidates;
    (void)search(basename, candidates);
    return candidates;
}

QList<HelperExecPath::HelperExec>
HelperExecPath::search(QString basename, QStringList &candidates)
{
    // Helpers are expected to exist either in the same directory as
    // this executable was found, or in a subdirectory called helpers.

    QString extension = "";
#ifdef _WIN32
    extension = ".exe";
#endif

    QList<HelperExec> executables;
    QStringList dirs = getHelperDirPaths();
    
    for (QString t: getTags()) {
        for (QString d: dirs) {
            QString path = d + QDir::separator() + basename;
            if (t != QString()) path += "-" + t;
            path += extension;
            candidates.push_back(path);
            if (isGood(path)) {
                executables.push_back({ path, t });
                break;
            }
        }
    }

    return executables;
}