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/*

    This file is part of the iText (R) project.
    Copyright (c) 1998-2020 iText Group NV
    Authors: Bruno Lowagie, Paulo Soares, et al.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License version 3
    as published by the Free Software Foundation with the addition of the
    following permission added to Section 15 as permitted in Section 7(a):
    FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
    ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
    OF THIRD PARTY RIGHTS

    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 Affero General Public License for more details.
    You should have received a copy of the GNU Affero General Public License
    along with this program; if not, see http://www.gnu.org/licenses or write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA, 02110-1301 USA, or download the license from the following URL:
    http://itextpdf.com/terms-of-use/

    The interactive user interfaces in modified source and object code versions
    of this program must display Appropriate Legal Notices, as required under
    Section 5 of the GNU Affero General Public License.

    In accordance with Section 7(b) of the GNU Affero General Public License,
    a covered work must retain the producer line in every PDF that is created
    or manipulated using iText.

    You can be released from the requirements of the license by purchasing
    a commercial license. Buying such a license is mandatory as soon as you
    develop commercial activities involving the iText software without
    disclosing the source code of your own applications.
    These activities include: offering paid services to customers as an ASP,
    serving PDFs on the fly in a web application, shipping iText with a closed
    source product.

    For more information, please contact iText Software Corp. at this
    address: [email protected]
 */
package com.itextpdf.io.util;

import com.itextpdf.io.IoExceptionMessage;

import java.io.IOException;

public class GhostscriptHelper {
    /**
     * The name of the environment variable with the command to execute Ghostscript operations.
     */
    public static final String GHOSTSCRIPT_ENVIRONMENT_VARIABLE = "ITEXT_GS_EXEC";

    @Deprecated
    static final String GHOSTSCRIPT_ENVIRONMENT_VARIABLE_LEGACY = "gsExec";

    static final String GHOSTSCRIPT_KEYWORD = "GPL Ghostscript";

    private static final String GHOSTSCRIPT_PARAMS = " -dSAFER -dNOPAUSE -dBATCH -sDEVICE=png16m -r150 {0} -sOutputFile=\"{1}\" \"{2}\"";

    private String gsExec;

    public GhostscriptHelper() {
        this(null);
    }

    public GhostscriptHelper(String newGsExec) {
        gsExec = newGsExec;
        if (gsExec == null) {
            gsExec = SystemUtil.getPropertyOrEnvironmentVariable(GHOSTSCRIPT_ENVIRONMENT_VARIABLE);

            if (gsExec == null) {
                gsExec = SystemUtil.getPropertyOrEnvironmentVariable(GHOSTSCRIPT_ENVIRONMENT_VARIABLE_LEGACY);
            }
        }

        if (!CliCommandUtil.isVersionCommandExecutable(gsExec, GHOSTSCRIPT_KEYWORD)) {
            throw new IllegalArgumentException(IoExceptionMessage.GS_ENVIRONMENT_VARIABLE_IS_NOT_SPECIFIED);
        }
    }

    /**
     * Returns a command that is used to run the utility.
     * This command doesn't contain command parameters. Parameters are added on specific
     * methods invocation.
     *
     * @return a string command
     */
    public String getCliExecutionCommand() {
        return gsExec;
    }

    /**
     * Runs ghostscript to create images of pdfs.
     *
     * @param pdf    Path to the pdf file.
     * @param outDir Path to the output directory
     * @param image  Path to the generated image
     * @throws IOException          if there are file's reading/writing issues
     * @throws InterruptedException if there is thread interruption while executing GhostScript.
     */
    public void runGhostScriptImageGeneration(String pdf, String outDir, String image) throws IOException, InterruptedException {
        runGhostScriptImageGeneration(pdf, outDir, image, null);
    }

    /**
     * Runs ghostscript to create images of specified pages of pdfs.
     *
     * @param pdf      Path to the pdf file.
     * @param outDir   Path to the output directory
     * @param image    Path to the generated image
     * @param pageList String with numbers of the required pages to extract as image. Should be formatted as string with
     *                 numbers, separated by commas, without whitespaces. Can be null, if it is required to extract
     *                 all pages as images.
     * @throws IOException          if there are file's reading/writing issues
     * @throws InterruptedException if there is thread interruption while executing GhostScript.
     */
    public void runGhostScriptImageGeneration(String pdf, String outDir, String image, String pageList)
            throws IOException, InterruptedException {
        if (!FileUtil.directoryExists(outDir)) {
            throw new IllegalArgumentException(IoExceptionMessage.CANNOT_OPEN_OUTPUT_DIRECTORY.replace("", pdf));
        }

        pageList = (pageList == null) ? "" : "-sPageList=".replace("", pageList);

        String currGsParams = MessageFormatUtil.format(GHOSTSCRIPT_PARAMS, pageList, outDir + image, pdf);
        if (!SystemUtil.runProcessAndWait(gsExec, currGsParams)) {
            throw new GhostscriptExecutionException(IoExceptionMessage.GHOSTSCRIPT_FAILED.replace("", pdf));
        }
    }

    /**
     * Exceptions thrown when errors occur during generation and comparison of images obtained on the basis of pdf
     * files.
     */
    public static class GhostscriptExecutionException extends RuntimeException {
        /**
         * Creates a new {@link GhostscriptExecutionException}.
         *
         * @param msg the detail message.
         */
        public GhostscriptExecutionException(String msg) {
            super(msg);
        }
    }
}