pdfsignatureappearance.java

处理PDF

/*
 * $Id: PdfSignatureAppearance.java 3264 2008-04-17 15:28:45Z psoares33 $
 *
 * Copyright 2004-2006 by Paulo Soares.
 *
 * The contents of this file are subject to the Mozilla Public License Version 1.1
 * (the "License"); you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the License.
 *
 * The Original Code is 'iText, a free JAVA-PDF library'.
 *
 * The Initial Developer of the Original Code is Bruno Lowagie. Portions created by
 * the Initial Developer are Copyright (C) 1999, 2000, 2001, 2002 by Bruno Lowagie.
 * All Rights Reserved.
 * Co-Developer of the code is Paulo Soares. Portions created by the Co-Developer
 * are Copyright (C) 2000, 2001, 2002 by Paulo Soares. All Rights Reserved.
 *
 * Contributor(s): all the names of the contributors are added in the source code
 * where applicable.
 *
 * Alternatively, the contents of this file may be used under the terms of the
 * LGPL license (the "GNU LIBRARY GENERAL PUBLIC LICENSE"), in which case the
 * provisions of LGPL are applicable instead of those above.  If you wish to
 * allow use of your version of this file only under the terms of the LGPL
 * License and not to allow others to use your version of this file under
 * the MPL, indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by the LGPL.
 * If you do not delete the provisions above, a recipient may use your version
 * of this file under either the MPL or the GNU LIBRARY GENERAL PUBLIC LICENSE.
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the MPL as stated above or under the terms of the GNU
 * Library General Public License as published by the Free Software Foundation;
 * either version 2 of the License, or any later version.
 *
 * This library 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 Library general Public License for more
 * details.
 *
 * If you didn't download this code from the following link, you should check if
 * you aren't using an obsolete version:
 * http://www.lowagie.com/iText/
 */
package com.lowagie.text.pdf;

import java.io.EOFException;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.RandomAccessFile;
import java.security.PrivateKey;
import java.security.cert.CRL;
import java.security.cert.Certificate;
import java.security.cert.X509Certificate;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import com.lowagie.text.Chunk;
import com.lowagie.text.DocumentException;
import com.lowagie.text.Element;
import com.lowagie.text.ExceptionConverter;
import com.lowagie.text.Font;
import com.lowagie.text.Image;
import com.lowagie.text.Paragraph;
import com.lowagie.text.Phrase;
import com.lowagie.text.Rectangle;

/**
 * This class takes care of the cryptographic options and appearances that form a signature.
 */
public class PdfSignatureAppearance {
    
    /**
     * The rendering mode is just the description
     */  
    public static final int SignatureRenderDescription = 0;
    /**
     * The rendering mode is the name of the signer and the description
     */
    public static final int SignatureRenderNameAndDescription = 1;
    /**
     * The rendering mode is an image and the description
     */
    public static final int SignatureRenderGraphicAndDescription = 2;

    /**
     * The self signed filter.
     */
    public static final PdfName SELF_SIGNED = PdfName.ADOBE_PPKLITE;
    /**
     * The VeriSign filter.
     */
    public static final PdfName VERISIGN_SIGNED = PdfName.VERISIGN_PPKVS;
    /**
     * The Windows Certificate Security.
     */
    public static final PdfName WINCER_SIGNED = PdfName.ADOBE_PPKMS;

    public static final int NOT_CERTIFIED = 0;
    public static final int CERTIFIED_NO_CHANGES_ALLOWED = 1;
    public static final int CERTIFIED_FORM_FILLING = 2;
    public static final int CERTIFIED_FORM_FILLING_AND_ANNOTATIONS = 3;
    
    private static final float TOP_SECTION = 0.3f;
    private static final float MARGIN = 2;
    private Rectangle rect;
    private Rectangle pageRect;
    private PdfTemplate app[] = new PdfTemplate[5];
    private PdfTemplate frm; 
    private PdfStamperImp writer;
    private String layer2Text;
    private String reason;
    private String location;
    private Calendar signDate;
    private String provider;
    private int page = 1;
    private String fieldName;
    private PrivateKey privKey;
    private Certificate[] certChain;
    private CRL[] crlList;
    private PdfName filter;
    private boolean newField;
    private ByteBuffer sigout;
    private OutputStream originalout;
    private File tempFile;
    private PdfDictionary cryptoDictionary;
    private PdfStamper stamper;
    private boolean preClosed = false;
    private PdfSigGenericPKCS sigStandard;
    private int range[];
    private RandomAccessFile raf;
    private byte bout[];
    private int boutLen;
    private byte externalDigest[];
    private byte externalRSAdata[];
    private String digestEncryptionAlgorithm;
    private HashMap exclusionLocations;
        
    PdfSignatureAppearance(PdfStamperImp writer) {
        this.writer = writer;
        signDate = new GregorianCalendar();
        fieldName = getNewSigName();
    }
    
    private int render = SignatureRenderDescription;

    /**
    * Gets the rendering mode for this signature.
    * @return the rendering mode for this signature
    */    
    public int getRender() {
        return render;
    }

    /**
     * Sets the rendering mode for this signature.
     * The rendering modes can be the constants <CODE>SignatureRenderDescription</CODE>,
     * <CODE>SignatureRenderNameAndDescription</CODE> or <CODE>SignatureRenderGraphicAndDescription</CODE>.
     * The two last modes should be used with Acrobat 6 layer type.
     * @param render the render mode
     */    
    public void setRender(int render) {
        this.render = render;
    }

    private Image signatureGraphic = null;

    /**
    * Gets the Image object to render.
    * @return the image
    */    
    public Image getSignatureGraphic() {
        return signatureGraphic;
    }

    /**
     * Sets the Image object to render when Render is set to <CODE>SignatureRenderGraphicAndDescription</CODE>
     * @param signatureGraphic image rendered. If <CODE>null</CODE> the mode is defaulted
     * to <CODE>SignatureRenderDescription</CODE>
     */    
    public void setSignatureGraphic(Image signatureGraphic) {
        this.signatureGraphic = signatureGraphic;
    }

    /**
     * Sets the signature text identifying the signer.
     * @param text the signature text identifying the signer. If <CODE>null</CODE> or not set
     * a standard description will be used
     */    
    public void setLayer2Text(String text) {
        layer2Text = text;
    }
    
    /**
     * Gets the signature text identifying the signer if set by setLayer2Text().
     * @return the signature text identifying the signer
     */    
    public String getLayer2Text() {
        return layer2Text;
    }
    
    /**
     * Sets the text identifying the signature status.
     * @param text the text identifying the signature status. If <CODE>null</CODE> or not set
     * the description "Signature Not Verified" will be used
     */    
    public void setLayer4Text(String text) {
        layer4Text = text;
    }
    
    /**
     * Gets the text identifying the signature status if set by setLayer4Text().
     * @return the text identifying the signature status
     */    
    public String getLayer4Text() {
        return layer4Text;
    }
    
    /**
     * Gets the rectangle representing the signature dimensions.
     * @return the rectangle representing the signature dimensions. It may be <CODE>null</CODE>
     * or have zero width or height for invisible signatures
     */    
    public Rectangle getRect() {
        return rect;
    }
    
    /**
     * Gets the visibility status of the signature.
     * @return the visibility status of the signature
     */    
    public boolean isInvisible() {
        return (rect == null || rect.getWidth() == 0 || rect.getHeight() == 0);
    }
    
    /**
     * Sets the cryptographic parameters.
     * @param privKey the private key
     * @param certChain the certificate chain
     * @param crlList the certificate revocation list. It may be <CODE>null</CODE>
     * @param filter the crytographic filter type. It can be SELF_SIGNED, VERISIGN_SIGNED or WINCER_SIGNED
     */    
    public void setCrypto(PrivateKey privKey, Certificate[] certChain, CRL[] crlList, PdfName filter) {
        this.privKey = privKey;
        this.certChain = certChain;
        this.crlList = crlList;
        this.filter = filter;
    }
    
    /**
     * Sets the signature to be visible. It creates a new visible signature field.
     * @param pageRect the position and dimension of the field in the page
     * @param page the page to place the field. The fist page is 1
     * @param fieldName the field name or <CODE>null</CODE> to generate automatically a new field name
     */    
    public void setVisibleSignature(Rectangle pageRect, int page, String fieldName) {
        if (fieldName != null) {
            if (fieldName.indexOf('.') >= 0)
                throw new IllegalArgumentException("Field names cannot contain a dot.");
            AcroFields af = writer.getAcroFields();
            AcroFields.Item item = af.getFieldItem(fieldName);
            if (item != null)
                throw new IllegalArgumentException("The field " + fieldName + " already exists.");
            this.fieldName = fieldName;
        }
        if (page < 1 || page > writer.reader.getNumberOfPages())
            throw new IllegalArgumentException("Invalid page number: " + page);
        this.pageRect = new Rectangle(pageRect);
        this.pageRect.normalize();
        rect = new Rectangle(this.pageRect.getWidth(), this.pageRect.getHeight());
        this.page = page;
        newField = true;
    }
    
    /**
     * Sets the signature to be visible. An empty signature field with the same name must already exist.
     * @param fieldName the existing empty signature field name
     */    
    public void setVisibleSignature(String fieldName) {
        AcroFields af = writer.getAcroFields();
        AcroFields.Item item = af.getFieldItem(fieldName);
        if (item == null)
            throw new IllegalArgumentException("The field " + fieldName + " does not exist.");
        PdfDictionary merged = (PdfDictionary)item.merged.get(0);
        if (!PdfName.SIG.equals(PdfReader.getPdfObject(merged.get(PdfName.FT))))
            throw new IllegalArgumentException("The field " + fieldName + " is not a signature field.");
        this.fieldName = fieldName;
        PdfArray r = (PdfArray)PdfReader.getPdfObject(merged.get(PdfName.RECT));
        ArrayList ar = r.getArrayList();
        float llx = ((PdfNumber)PdfReader.getPdfObject((PdfObject)ar.get(0))).floatValue();
        float lly = ((PdfNumber)PdfReader.getPdfObject((PdfObject)ar.get(1))).floatValue();
        float urx = ((PdfNumber)PdfReader.getPdfObject((PdfObject)ar.get(2))).floatValue();
        float ury = ((PdfNumber)PdfReader.getPdfObject((PdfObject)ar.get(3))).floatValue();
        pageRect = new Rectangle(llx, lly, urx, ury);
        pageRect.normalize();
        page = ((Integer)item.page.get(0)).intValue();
        int rotation = writer.reader.getPageRotation(page);
        Rectangle pageSize = writer.reader.getPageSizeWithRotation(page);
        switch (rotation) {
            case 90:
                pageRect = new Rectangle(
                pageRect.getBottom(),
                pageSize.getTop() - pageRect.getLeft(),
                pageRect.getTop(),
                pageSize.getTop() - pageRect.getRight());
                break;
            case 180:
                pageRect = new Rectangle(
                pageSize.getRight() - pageRect.getLeft(),
                pageSize.getTop() - pageRect.getBottom(),
                pageSize.getRight() - pageRect.getRight(),
                pageSize.getTop() - pageRect.getTop());
                break;
            case 270:
                pageRect = new Rectangle(
                pageSize.getRight() - pageRect.getBottom(),
                pageRect.getLeft(),
                pageSize.getRight() - pageRect.getTop(),
                pageRect.getRight());
                break;
        }
        if (rotation != 0)
            pageRect.normalize();
        rect = new Rectangle(this.pageRect.getWidth(), this.pageRect.getHeight());
    }
    
    /**
     * Gets a template layer to create a signature appearance. The layers can go from 0 to 4.
     * <p>
     * Consult <A HREF="http://partners.adobe.com/asn/developer/pdfs/tn/PPKAppearances.pdf">PPKAppearances.pdf</A>
     * for further details.
     * @param layer the layer
     * @return a template
     */    
    public PdfTemplate getLayer(int layer) {
        if (layer < 0 || layer >= app.length)
            return null;
        PdfTemplate t = app[layer];
        if (t == null) {
            t = app[layer] = new PdfTemplate(writer);
            t.setBoundingBox(rect);
            writer.addDirectTemplateSimple(t, new PdfName("n" + layer));
        }
        return t;
    }
    
    /**
     * Gets the template that aggregates all appearance layers. This corresponds to the /FRM resource.
     * <p>
     * Consult <A HREF="http://partners.adobe.com/asn/developer/pdfs/tn/PPKAppearances.pdf">PPKAppearances.pdf</A>
     * for further details.
     * @return the template that aggregates all appearance layers
     */