renderer_create.cpp

/*
 * Interface for file format renderers.
 * Copyright (c) 2021-2026 Benjamin Johnson
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <QString>
#include <QMutex>
#include <QMutexLocker>
#include <QMimeType>
#include <QMimeDatabase>

#include "renderer.h"

// Available renderers
// List alphabetically by name
#include "render_hexdump.h"
#include "render_image.h"
#include "render_pdf.h"
#include "render_ps.h"
#include "render_text.h"
#include "render_xps.h"

static QString loadError;
static QMutex loadErrorMutex;

/*
 * Return an appropriate renderer subclass for the specified path.
 * If this fails, it will return nullptr and put error details in errorOut.
 */
Renderer *Renderer::create(const QString &path, QString *errorOut)
{
    Renderer *renderer;
    QMimeDatabase mimeDatabase;
    QMimeType mimeType = mimeDatabase.mimeTypeForFile(path);

    QMutexLocker locker(&loadErrorMutex);
    loadError.clear();

    // Specific MIME types
    // List alphabetically by name
    if (mimeType.inherits("application/oxps")
        || mimeType.inherits("application/xps"))
        renderer = new XPSRenderer;

    else if (mimeType.inherits("application/pdf"))
        renderer = new PDFRenderer;

    else if (mimeType.inherits("application/postscript"))
        renderer = new PSRenderer;

    // More generic MIME types
    // These come last since more specific types may inherit from them
    else if (mimeType.name().startsWith("image/"))
        renderer = new ImageRenderer;
    else if (mimeType.inherits("text/plain"))
        renderer = new TextRenderer;

    // Fallback if we can't identify this file
    else
        renderer = new HexDumpRenderer;

    renderer->path_ = path;
    if (!(renderer->loaded_ = renderer->load())) {
        if (errorOut != nullptr)
            *errorOut = loadError;
        loadError.clear();
        delete renderer;
        renderer = nullptr;
    }
    return renderer;
}

/*
 * Initialize renderers that need additional configuration.
 */
void Renderer::init()
{
    PDFRenderer::init();
}

/*
 * Store errors that occurred while loading the document.
 * Note the mutex has already been locked by Renderer::create().
 */
void Renderer::storeLoadError(const QString &message)
{
    // Do not clear loadError here; we want to store all errors that occur
    // during any given load attempt
    if (!loadError.isEmpty())
        loadError += "\n";
    loadError += message;
}