/src/share/classes/sun/awt/datatransfer/DataTransferer.java

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/*
 * Copyright (c) 2000, 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package sun.awt.datatransfer;

import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Image;
import java.awt.Toolkit;

import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.FlavorMap;
import java.awt.datatransfer.FlavorTable;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Reader;
import java.io.SequenceInputStream;
import java.io.StringReader;

import java.net.URI;
import java.net.URISyntaxException;

import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.IllegalCharsetNameException;
import java.nio.charset.UnsupportedCharsetException;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;

import java.security.AccessController;
import java.security.PrivilegedAction;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.security.ProtectionDomain;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.Set;
import java.util.Stack;
import java.util.TreeMap;
import java.util.TreeSet;

import sun.awt.ComponentFactory;
import sun.util.logging.PlatformLogger;

import sun.awt.AppContext;
import sun.awt.SunToolkit;

import java.awt.image.BufferedImage;
import java.awt.image.ImageObserver;
import java.awt.image.RenderedImage;
import java.awt.image.WritableRaster;
import java.awt.image.ColorModel;

import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.ImageReadParam;
import javax.imageio.ImageWriter;
import javax.imageio.ImageTypeSpecifier;

import javax.imageio.spi.ImageWriterSpi;

import javax.imageio.stream.ImageInputStream;
import javax.imageio.stream.ImageOutputStream;

import sun.awt.image.ImageRepresentation;
import sun.awt.image.ToolkitImage;

import java.io.FilePermission;


/**
 * Provides a set of functions to be shared among the DataFlavor class and
 * platform-specific data transfer implementations.
 *
 * The concept of "flavors" and "natives" is extended to include "formats",
 * which are the numeric values Win32 and X11 use to express particular data
 * types. Like FlavorMap, which provides getNativesForFlavors(DataFlavor[]) and
 * getFlavorsForNatives(String[]) functions, DataTransferer provides a set
 * of getFormatsFor(Transferable|Flavor|Flavors) and
 * getFlavorsFor(Format|Formats) functions.
 *
 * Also provided are functions for translating a Transferable into a byte
 * array, given a source DataFlavor and a target format, and for translating
 * a byte array or InputStream into an Object, given a source format and
 * a target DataFlavor.
 *
 * @author David Mendenhall
 * @author Danila Sinopalnikov
 *
 * @since 1.3.1
 */
public abstract class DataTransferer {

    /**
     * The <code>DataFlavor</code> representing plain text with Unicode
     * encoding, where:
     * <pre>
     *     representationClass = java.lang.String
     *     mimeType            = "text/plain; charset=Unicode"
     * </pre>
     */
    public static final DataFlavor plainTextStringFlavor;

    /**
     * The <code>DataFlavor</code> representing a Java text encoding String
     * encoded in UTF-8, where
     * <pre>
     *     representationClass = [B
     *     mimeType            = "application/x-java-text-encoding"
     * </pre>
     */
    public static final DataFlavor javaTextEncodingFlavor;

    /**
     * Lazy initialization of Standard Encodings.
     */
    private static class StandardEncodingsHolder {
        private static final SortedSet<String> standardEncodings = load();

        private static SortedSet<String> load() {
            final Comparator comparator =
                    new CharsetComparator(IndexedComparator.SELECT_WORST);
            final SortedSet<String> tempSet = new TreeSet<String>(comparator);
            tempSet.add("US-ASCII");
            tempSet.add("ISO-8859-1");
            tempSet.add("UTF-8");
            tempSet.add("UTF-16BE");
            tempSet.add("UTF-16LE");
            tempSet.add("UTF-16");
            tempSet.add(getDefaultTextCharset());
            return Collections.unmodifiableSortedSet(tempSet);
        }
    }

    /**
     * Tracks whether a particular text/* MIME type supports the charset
     * parameter. The Map is initialized with all of the standard MIME types
     * listed in the DataFlavor.selectBestTextFlavor method comment. Additional
     * entries may be added during the life of the JRE for text/<other> types.
     */
    private static final Map textMIMESubtypeCharsetSupport;

    /**
     * Cache of the platform default encoding as specified in the
     * "file.encoding" system property.
     */
    private static String defaultEncoding;

    /**
     * A collection of all natives listed in flavormap.properties with
     * a primary MIME type of "text".
     */
    private static final Set textNatives =
        Collections.synchronizedSet(new HashSet());

    /**
     * The native encodings/charsets for the Set of textNatives.
     */
    private static final Map nativeCharsets =
        Collections.synchronizedMap(new HashMap());

    /**
     * The end-of-line markers for the Set of textNatives.
     */
    private static final Map nativeEOLNs =
        Collections.synchronizedMap(new HashMap());

    /**
     * The number of terminating NUL bytes for the Set of textNatives.
     */
    private static final Map nativeTerminators =
        Collections.synchronizedMap(new HashMap());

    /**
     * The key used to store pending data conversion requests for an AppContext.
     */
    private static final String DATA_CONVERTER_KEY = "DATA_CONVERTER_KEY";

    /**
     * The singleton DataTransferer instance. It is created during MToolkit
     * or WToolkit initialization.
     */
    private static DataTransferer transferer;

    private static final PlatformLogger dtLog = PlatformLogger.getLogger("sun.awt.datatransfer.DataTransfer");

    static {
        DataFlavor tPlainTextStringFlavor = null;
        try {
            tPlainTextStringFlavor = new DataFlavor
                ("text/plain;charset=Unicode;class=java.lang.String");
        } catch (ClassNotFoundException cannotHappen) {
        }
        plainTextStringFlavor = tPlainTextStringFlavor;

        DataFlavor tJavaTextEncodingFlavor = null;
        try {
            tJavaTextEncodingFlavor = new DataFlavor
                ("application/x-java-text-encoding;class=\"[B\"");
        } catch (ClassNotFoundException cannotHappen) {
        }
        javaTextEncodingFlavor = tJavaTextEncodingFlavor;

        Map tempMap = new HashMap(17);
        tempMap.put("sgml", Boolean.TRUE);
        tempMap.put("xml", Boolean.TRUE);
        tempMap.put("html", Boolean.TRUE);
        tempMap.put("enriched", Boolean.TRUE);
        tempMap.put("richtext", Boolean.TRUE);
        tempMap.put("uri-list", Boolean.TRUE);
        tempMap.put("directory", Boolean.TRUE);
        tempMap.put("css", Boolean.TRUE);
        tempMap.put("calendar", Boolean.TRUE);
        tempMap.put("plain", Boolean.TRUE);
        tempMap.put("rtf", Boolean.FALSE);
        tempMap.put("tab-separated-values", Boolean.FALSE);
        tempMap.put("t140", Boolean.FALSE);
        tempMap.put("rfc822-headers", Boolean.FALSE);
        tempMap.put("parityfec", Boolean.FALSE);
        textMIMESubtypeCharsetSupport = Collections.synchronizedMap(tempMap);
    }

    /**
     * The accessor method for the singleton DataTransferer instance. Note
     * that in a headless environment, there may be no DataTransferer instance;
     * instead, null will be returned.
     */
    public static synchronized DataTransferer getInstance() {
        return ((ComponentFactory) Toolkit.getDefaultToolkit()).getDataTransferer();
    }

    /**
     * Converts an arbitrary text encoding to its canonical name.
     */
    public static String canonicalName(String encoding) {
        if (encoding == null) {
            return null;
        }
        try {
            return Charset.forName(encoding).name();
        } catch (IllegalCharsetNameException icne) {
            return encoding;
        } catch (UnsupportedCharsetException uce) {
            return encoding;
        }
    }

    /**
     * If the specified flavor is a text flavor which supports the "charset"
     * parameter, then this method returns that parameter, or the default
     * charset if no such parameter was specified at construction. For non-
     * text DataFlavors, and for non-charset text flavors, this method returns
     * null.
     */
    public static String getTextCharset(DataFlavor flavor) {
        if (!isFlavorCharsetTextType(flavor)) {
            return null;
        }

        String encoding = flavor.getParameter("charset");

        return (encoding != null) ? encoding : getDefaultTextCharset();
    }

    /**
     * Returns the platform's default character encoding.
     */
    public static String getDefaultTextCharset() {
        if (defaultEncoding != null) {
            return defaultEncoding;
        }
        return defaultEncoding = Charset.defaultCharset().name();
    }

    /**
     * Tests only whether the flavor's MIME type supports the charset
     * parameter. Must only be called for flavors with a primary type of
     * "text".
     */
    public static boolean doesSubtypeSupportCharset(DataFlavor flavor) {
        if (dtLog.isLoggable(PlatformLogger.Level.FINE)) {
            if (!"text".equals(flavor.getPrimaryType())) {
                dtLog.fine("Assertion (\"text\".equals(flavor.getPrimaryType())) failed");
            }
        }

        String subType = flavor.getSubType();
        if (subType == null) {
            return false;
        }

        Object support = textMIMESubtypeCharsetSupport.get(subType);

        if (support != null) {
            return (support == Boolean.TRUE);
        }

        boolean ret_val = (flavor.getParameter("charset") != null);
        textMIMESubtypeCharsetSupport.put
            (subType, (ret_val) ? Boolean.TRUE : Boolean.FALSE);
        return ret_val;
    }
    public static boolean doesSubtypeSupportCharset(String subType,
                                                    String charset)
    {
        Object support = textMIMESubtypeCharsetSupport.get(subType);

        if (support != null) {
            return (support == Boolean.TRUE);
        }

        boolean ret_val = (charset != null);
        textMIMESubtypeCharsetSupport.put
            (subType, (ret_val) ? Boolean.TRUE : Boolean.FALSE);
        return ret_val;
    }

    /**
     * Returns whether this flavor is a text type which supports the
     * 'charset' parameter.
     */
    public static boolean isFlavorCharsetTextType(DataFlavor flavor) {
        // Although stringFlavor doesn't actually support the charset
        // parameter (because its primary MIME type is not "text"), it should
        // be treated as though it does. stringFlavor is semantically
        // equivalent to "text/plain" data.
        if (DataFlavor.stringFlavor.equals(flavor)) {
            return true;
        }

        if (!"text".equals(flavor.getPrimaryType()) ||
            !doesSubtypeSupportCharset(flavor))
        {
            return false;
        }

        Class rep_class = flavor.getRepresentationClass();

        if (flavor.isRepresentationClassReader() ||
            String.class.equals(rep_class) ||
            flavor.isRepresentationClassCharBuffer() ||
            char[].class.equals(rep_class))
        {
            return true;
        }

        if (!(flavor.isRepresentationClassInputStream() ||
              flavor.isRepresentationClassByteBuffer() ||
              byte[].class.equals(rep_class))) {
            return false;
        }

        String charset = flavor.getParameter("charset");

        return (charset != null)
            ? DataTransferer.isEncodingSupported(charset)
            : true; // null equals default encoding which is always supported
    }

    /**
     * Returns whether this flavor is a text type which does not support the
     * 'charset' parameter.
     */
    public static boolean isFlavorNoncharsetTextType(DataFlavor flavor) {
        if (!"text".equals(flavor.getPrimaryType()) ||
            doesSubtypeSupportCharset(flavor))
        {
            return false;
        }

        return (flavor.isRepresentationClassInputStream() ||
                flavor.isRepresentationClassByteBuffer() ||
                byte[].class.equals(flavor.getRepresentationClass()));
    }

    /**
     * Determines whether this JRE can both encode and decode text in the
     * specified encoding.
     */
    public static boolean isEncodingSupported(String encoding) {
        if (encoding == null) {
            return false;
        }
        try {
            return Charset.isSupported(encoding);
        } catch (IllegalCharsetNameException icne) {
            return false;
        }
    }

    /**
     * Returns {@code true} if the given type is a java.rmi.Remote.
     */
    public static boolean isRemote(Class<?> type) {
        return RMI.isRemote(type);
    }

    /**
     * Returns an Iterator which traverses a SortedSet of Strings which are
     * a total order of the standard character sets supported by the JRE. The
     * ordering follows the same principles as DataFlavor.selectBestTextFlavor.
     * So as to avoid loading all available character converters, optional,
     * non-standard, character sets are not included.
     */
    public static Set <String> standardEncodings() {
        return StandardEncodingsHolder.standardEncodings;
    }

    /**
     * Converts a FlavorMap to a FlavorTable.
     */
    public static FlavorTable adaptFlavorMap(final FlavorMap map) {
        if (map instanceof FlavorTable) {
            return (FlavorTable)map;
        }

        return new FlavorTable() {
                public Map getNativesForFlavors(DataFlavor[] flavors) {
                    return map.getNativesForFlavors(flavors);
                }
                public Map getFlavorsForNatives(String[] natives) {
                    return map.getFlavorsForNatives(natives);
                }
                public List getNativesForFlavor(DataFlavor flav) {
                    Map natives =
                        getNativesForFlavors(new DataFlavor[] { flav } );
                    String nat = (String)natives.get(flav);
                    if (nat != null) {
                        List list = new ArrayList(1);
                        list.add(nat);
                        return list;
                    } else {
                        return Collections.EMPTY_LIST;
                    }
                }
                public List getFlavorsForNative(String nat) {
                    Map flavors =
                        getFlavorsForNatives(new String[] { nat } );
                    DataFlavor flavor = (DataFlavor)flavors.get(nat);
                    if (flavor != null) {
                        List list = new ArrayList(1);
                        list.add(flavor);
                        return list;
                    } else {
                        return Collections.EMPTY_LIST;
                    }
                }
            };
    }

    /**
     * Returns the default Unicode encoding for the platform. The encoding
     * need not be canonical. This method is only used by the archaic function
     * DataFlavor.getTextPlainUnicodeFlavor().
     */
    public abstract String getDefaultUnicodeEncoding();

    /**
     * This method is called for text flavor mappings established while parsing
     * the flavormap.properties file. It stores the "eoln" and "terminators"
     * parameters which are not officially part of the MIME type. They are
     * MIME parameters specific to the flavormap.properties file format.
     */
    public void registerTextFlavorProperties(String nat, String charset,
                                             String eoln, String terminators) {
        Long format = getFormatForNativeAsLong(nat);

        textNatives.add(format);
        nativeCharsets.put(format, (charset != null && charset.length() != 0)
            ? charset : getDefaultTextCharset());
        if (eoln != null && eoln.length() != 0 && !eoln.equals("\n")) {
            nativeEOLNs.put(format, eoln);
        }
        if (terminators != null && terminators.length() != 0) {
            Integer iTerminators = Integer.valueOf(terminators);
            if (iTerminators.intValue() > 0) {
                nativeTerminators.put(format, iTerminators);
            }
        }
    }

    /**
     * Determines whether the native corresponding to the specified long format
     * was listed in the flavormap.properties file.
     */
    protected boolean isTextFormat(long format) {
        return textNatives.contains(Long.valueOf(format));
    }

    protected String getCharsetForTextFormat(Long lFormat) {
        return (String)nativeCharsets.get(lFormat);
    }

    /**
     * Specifies whether text imported from the native system in the specified
     * format is locale-dependent. If so, when decoding such text,
     * 'nativeCharsets' should be ignored, and instead, the Transferable should
     * be queried for its javaTextEncodingFlavor data for the correct encoding.
     */
    public abstract boolean isLocaleDependentTextFormat(long format);

    /**
     * Determines whether the DataFlavor corresponding to the specified long
     * format is DataFlavor.javaFileListFlavor.
     */
    public abstract boolean isFileFormat(long format);

    /**
     * Determines whether the DataFlavor corresponding to the specified long
     * format is DataFlavor.imageFlavor.
     */
    public abstract boolean isImageFormat(long format);

    /**
     * Determines whether the format is a URI list we can convert to
     * a DataFlavor.javaFileListFlavor.
     */
    protected boolean isURIListFormat(long format) {
        return false;
    }

    /**
     * Returns a Map whose keys are all of the possible formats into which the
     * Transferable's transfer data flavors can be translated. The value of
     * each key is the DataFlavor in which the Transferable's data should be
     * requested when converting to the format.
     * <p>
     * The map keys are sorted according to the native formats preference
     * order.
     */
    public SortedMap<Long,DataFlavor> getFormatsForTransferable(
                               Transferable contents, FlavorTable map)
    {
        DataFlavor[] flavors = contents.getTransferDataFlavors();
        if (flavors == null) {
            return new TreeMap();
        }
        return getFormatsForFlavors(flavors, map);
    }

    /**
     * Returns a Map whose keys are all of the possible formats into which data
     * in the specified DataFlavor can be translated. The value of each key
     * is the DataFlavor in which a Transferable's data should be requested
     * when converting to the format.
     * <p>
     * The map keys are sorted according to the native formats preference
     * order.
     */
    public SortedMap getFormatsForFlavor(DataFlavor flavor, FlavorTable map) {
        return getFormatsForFlavors(new DataFlavor[] { flavor },
                                    map);
    }

    /**
     * Returns a Map whose keys are all of the possible formats into which data
     * in the specified DataFlavors can be translated. The value of each key
     * is the DataFlavor in which the Transferable's data should be requested
     * when converting to the format.
     * <p>
     * The map keys are sorted according to the native formats preference
     * order.
     *
     * @param flavors the data flavors
     * @param map the FlavorTable which contains mappings between
     *            DataFlavors and data formats
     * @throws NullPointerException if flavors or map is <code>null</code>
     */
    public SortedMap <Long, DataFlavor> getFormatsForFlavors(
        DataFlavor[] flavors, FlavorTable map)
    {
        Map <Long,DataFlavor> formatMap =
            new HashMap <> (flavors.length);
        Map <Long,DataFlavor> textPlainMap =
            new HashMap <> (flavors.length);
        // Maps formats to indices that will be used to sort the formats
        // according to the preference order.
        // Larger index value corresponds to the more preferable format.
        Map indexMap = new HashMap(flavors.length);
        Map textPlainIndexMap = new HashMap(flavors.length);

        int currentIndex = 0;

        // Iterate backwards so that preferred DataFlavors are used over
        // other DataFlavors. (See javadoc for
        // Transferable.getTransferDataFlavors.)
        for (int i = flavors.length - 1; i >= 0; i--) {
            DataFlavor flavor = flavors[i];
            if (flavor == null) continue;

            // Don't explicitly test for String, since it is just a special
            // case of Serializable
            if (flavor.isFlavorTextType() ||
                flavor.isFlavorJavaFileListType() ||
                DataFlavor.imageFlavor.equals(flavor) ||
                flavor.isRepresentationClassSerializable() ||
                flavor.isRepresentationClassInputStream() ||
                flavor.isRepresentationClassRemote())
            {
                List natives = map.getNativesForFlavor(flavor);

                currentIndex += natives.size();

                for (Iterator iter = natives.iterator(); iter.hasNext(); ) {
                    Long lFormat =
                        getFormatForNativeAsLong((String)iter.next());
                    Integer index = Integer.valueOf(currentIndex--);

                    formatMap.put(lFormat, flavor);
                    indexMap.put(lFormat, index);

                    // SystemFlavorMap.getNativesForFlavor will return
                    // text/plain natives for all text/*. While this is good
                    // for a single text/* flavor, we would prefer that
                    // text/plain native data come from a text/plain flavor.
                    if (("text".equals(flavor.getPrimaryType()) &&
                         "plain".equals(flavor.getSubType())) ||
                        flavor.equals(DataFlavor.stringFlavor))
                    {
                        textPlainMap.put(lFormat, flavor);
                        textPlainIndexMap.put(lFormat, index);
                    }
                }

                currentIndex += natives.size();
            }
        }

        formatMap.putAll(textPlainMap);
        indexMap.putAll(textPlainIndexMap);

        // Sort the map keys according to the formats preference order.
        Comparator comparator =
            new IndexOrderComparator(indexMap, IndexedComparator.SELECT_WORST);
        SortedMap sortedMap = new TreeMap(comparator);
        sortedMap.putAll(formatMap);

        return sortedMap;
    }

    /**
     * Reduces the Map output for the root function to an array of the
     * Map's keys.
     */
    public long[] getFormatsForTransferableAsArray(Transferable contents,
                                                   FlavorTable map) {
        return keysToLongArray(getFormatsForTransferable(contents, map));
    }
    public long[] getFormatsForFlavorAsArray(DataFlavor flavor,
                                             FlavorTable map) {
        return keysToLongArray(getFormatsForFlavor(flavor, map));
    }
    public long[] getFormatsForFlavorsAsArray(DataFlavor[] flavors,
                                              FlavorTable map) {
        return keysToLongArray(getFormatsForFlavors(flavors, map));
    }

    /**
     * Returns a Map whose keys are all of the possible DataFlavors into which
     * data in the specified format can be translated. The value of each key
     * is the format in which the Clipboard or dropped data should be requested
     * when converting to the DataFlavor.
     */
    public Map getFlavorsForFormat(long format, FlavorTable map) {
        return getFlavorsForFormats(new long[] { format }, map);
    }

    /**
     * Returns a Map whose keys are all of the possible DataFlavors into which
     * data in the specified formats can be translated. The value of each key
     * is the format in which the Clipboard or dropped data should be requested
     * when converting to the DataFlavor.
     */
    public Map getFlavorsForFormats(long[] formats, FlavorTable map) {
        Map flavorMap = new HashMap(formats.length);
        Set mappingSet = new HashSet(formats.length);
        Set flavorSet = new HashSet(formats.length);

        // First step: build flavorSet, mappingSet and initial flavorMap
        // flavorSet  - the set of all the DataFlavors into which
        //              data in the specified formats can be translated;
        // mappingSet - the set of all the mappings from the specified formats
        //              into any DataFlavor;
        // flavorMap  - after this step, this map maps each of the DataFlavors
        //              from flavorSet to any of the specified formats.
        for (int i = 0; i < formats.length; i++) {
            long format = formats[i];
            String nat = getNativeForFormat(format);
            List flavors = map.getFlavorsForNative(nat);

            for (Iterator iter = flavors.iterator(); iter.hasNext(); ) {
                DataFlavor flavor = (DataFlavor)iter.next();

                // Don't explicitly test for String, since it is just a special
                // case of Serializable
                if (flavor.isFlavorTextType() ||
                    flavor.isFlavorJavaFileListType() ||
                    DataFlavor.imageFlavor.equals(flavor) ||
                    flavor.isRepresentationClassSerializable() ||
                    flavor.isRepresentationClassInputStream() ||
                    flavor.isRepresentationClassRemote())
                {
                    Long lFormat = Long.valueOf(format);
                    Object mapping =
                        DataTransferer.createMapping(lFormat, flavor);
                    flavorMap.put(flavor, lFormat);
                    mappingSet.add(mapping);
                    flavorSet.add(flavor);
                }
            }
        }

        // Second step: for each DataFlavor try to figure out which of the
        // specified formats is the best to translate to this flavor.
        // Then map each flavor to the best format.
        // For the given flavor, FlavorTable indicates which native will
        // best reflect data in the specified flavor to the underlying native
        // platform. We assume that this native is the best to translate
        // to this flavor.
        // Note: FlavorTable allows one-way mappings, so we can occasionally
        // map a flavor to the format for which the corresponding
        // format-to-flavor mapping doesn't exist. For this reason we have built
        // a mappingSet of all format-to-flavor mappings for the specified formats
        // and check if the format-to-flavor mapping exists for the
        // (flavor,format) pair being added.
        for (Iterator flavorIter = flavorSet.iterator();
             flavorIter.hasNext(); ) {
            DataFlavor flavor = (DataFlavor)flavorIter.next();

            List natives = map.getNativesForFlavor(flavor);

            for (Iterator nativeIter = natives.iterator();
                 nativeIter.hasNext(); ) {
                Long lFormat =
                    getFormatForNativeAsLong((String)nativeIter.next());
                Object mapping = DataTransferer.createMapping(lFormat, flavor);

                if (mappingSet.contains(mapping)) {
                    flavorMap.put(flavor, lFormat);
                    break;
                }
            }
        }

        return flavorMap;
    }

    /**
     * Returns a Set of all DataFlavors for which
     * 1) a mapping from at least one of the specified formats exists in the
     * specified map and
     * 2) the data translation for this mapping can be performed by the data
     * transfer subsystem.
     *
     * @param formats the data formats
     * @param map the FlavorTable which contains mappings between
     *            DataFlavors and data formats
     * @throws NullPointerException if formats or map is <code>null</code>
     */
    public Set getFlavorsForFormatsAsSet(long[] formats, FlavorTable map) {
        Set flavorSet = new HashSet(formats.length);

        for (int i = 0; i < formats.length; i++) {
            String nat = getNativeForFormat(formats[i]);
            List flavors = map.getFlavorsForNative(nat);

            for (Iterator iter = flavors.iterator(); iter.hasNext(); ) {
                DataFlavor flavor = (DataFlavor)iter.next();

                // Don't explicitly test for String, since it is just a special
                // case of Serializable
                if (flavor.isFlavorTextType() ||
                    flavor.isFlavorJavaFileListType() ||
                    DataFlavor.imageFlavor.equals(flavor) ||
                    flavor.isRepresentationClassSerializable() ||
                    flavor.isRepresentationClassInputStream() ||
                    flavor.isRepresentationClassRemote())
                {
                    flavorSet.add(flavor);
                }
            }
        }

        return flavorSet;
    }

    /**
     * Returns an array of all DataFlavors for which
     * 1) a mapping from the specified format exists in the specified map and
     * 2) the data translation for this mapping can be performed by the data
     * transfer subsystem.
     * The array will be sorted according to a
     * <code>DataFlavorComparator</code> created with the specified
     * map as an argument.
     *
     * @param format the data format
     * @param map the FlavorTable which contains mappings between
     *            DataFlavors and data formats
     * @throws NullPointerException if map is <code>null</code>
     */
    public DataFlavor[] getFlavorsForFormatAsArray(long format,
                                                   FlavorTable map) {
        return getFlavorsForFormatsAsArray(new long[] { format }, map);
    }

    /**
     * Returns an array of all DataFlavors for which
     * 1) a mapping from at least one of the specified formats exists in the
     * specified map and
     * 2) the data translation for this mapping can be performed by the data
     * transfer subsystem.
     * The array will be sorted according to a
     * <code>DataFlavorComparator</code> created with the specified
     * map as an argument.
     *
     * @param formats the data formats
     * @param map the FlavorTable which contains mappings between
     *            DataFlavors and data formats
     * @throws NullPointerException if formats or map is <code>null</code>
     */
    public DataFlavor[] getFlavorsForFormatsAsArray(long[] formats,
                                                    FlavorTable map) {
        // getFlavorsForFormatsAsSet() is less expensive than
        // getFlavorsForFormats().
        return setToSortedDataFlavorArray(getFlavorsForFormatsAsSet(formats, map));
    }

    /**
     * Returns an object that represents a mapping between the specified
     * key and value. <tt>null</tt> values and the <tt>null</tt> keys are
     * permitted. The internal representation of the mapping object is
     * irrelevant. The only requrement is that the two mapping objects are equal
     * if and only if their keys are equal and their values are equal.
     * More formally, the two mapping objects are equal if and only if
     * <tt>(value1 == null ? value2 == null : value1.equals(value2))
     * && (key1 == null ? key2 == null : key1.equals(key2))</tt>.
     */
    private static Object createMapping(Object key, Object value) {
        // NOTE: Should be updated to use AbstractMap.SimpleEntry as
        // soon as it is made public.
        return Arrays.asList(new Object[] { key, value });
    }

    /**
     * Looks-up or registers the String native with the native data transfer
     * system and returns a long format corresponding to that native.
     */
    protected abstract Long getFormatForNativeAsLong(String str);

    /**
     * Looks-up the String native corresponding to the specified long format in
     * the native data transfer system.
     */
    protected abstract String getNativeForFormat(long format);

    /* Contains common code for finding the best charset for
     * clipboard string encoding/decoding, basing on clipboard
     * format and localeTransferable(on decoding, if available)
     */
    private String getBestCharsetForTextFormat(Long lFormat,
        Transferable localeTransferable) throws IOException
    {
        String charset = null;
        if (localeTransferable != null &&
            isLocaleDependentTextFormat(lFormat) &&
            localeTransferable.isDataFlavorSupported(javaTextEncodingFlavor))
        {
            try {
                charset = new String(
                    (byte[])localeTransferable.getTransferData(javaTextEncodingFlavor),
                    "UTF-8"
                );
            } catch (UnsupportedFlavorException cannotHappen) {
            }
        } else {
            charset = getCharsetForTextFormat(lFormat);
        }
        if (charset == null) {
            // Only happens when we have a custom text type.
            charset = getDefaultTextCharset();
        }
        return charset;
    }

    /**
     *  Translation function for converting string into
     *  a byte array. Search-and-replace EOLN. Encode into the
     *  target format. Append terminating NUL bytes.
     *
     *  Java to Native string conversion
     */
    private byte[] translateTransferableString(String str,
                                               long format) throws IOException
    {
        Long lFormat = Long.valueOf(format);
        String charset = getBestCharsetForTextFormat(lFormat, null);
        // Search and replace EOLN. Note that if EOLN is "\n", then we
        // never added an entry to nativeEOLNs anyway, so we'll skip this
        // code altogether.
        // windows: "abc\nde"->"abc\r\nde"
        String eoln = (String)nativeEOLNs.get(lFormat);
        if (eoln != null) {
            int length = str.length();
            StringBuffer buffer =
                new StringBuffer(length * 2); // 2 is a heuristic
            for (int i = 0; i < length; i++) {
                // Fix for 4914613 - skip native EOLN
                if (str.startsWith(eoln, i)) {
                    buffer.append(eoln);
                    i += eoln.length() - 1;
                    continue;
                }
                char c = str.charAt(i);
                if (c == '\n') {
                    buffer.append(eoln);
                } else {
                    buffer.append(c);
                }
            }
            str = buffer.toString();
        }

        // Encode text in target format.
        byte[] bytes = str.getBytes(charset);

        // Append terminating NUL bytes. Note that if terminators is 0,
        // the we never added an entry to nativeTerminators anyway, so
        // we'll skip code altogether.
        // "abcde" -> "abcde\0"
        Integer terminators = (Integer)nativeTerminators.get(lFormat);
        if (terminators != null) {
            int numTerminators = terminators.intValue();
            byte[] terminatedBytes =
                new byte[bytes.length + numTerminators];
            System.arraycopy(bytes, 0, terminatedBytes, 0, bytes.length);
            for (int i = bytes.length; i < terminatedBytes.length; i++) {
                terminatedBytes[i] = 0x0;
            }
            bytes = terminatedBytes;
        }
        return bytes;
    }

    /**
     * Translating either a byte array or an InputStream into an String.
     * Strip terminators and search-and-replace EOLN.
     *
     * Native to Java string conversion
     */
    private String translateBytesToString(byte[] bytes, long format,
                                          Transferable localeTransferable)
            throws IOException
    {

        Long lFormat = Long.valueOf(format);
        String charset = getBestCharsetForTextFormat(lFormat, localeTransferable);

        // Locate terminating NUL bytes. Note that if terminators is 0,
        // the we never added an entry to nativeTerminators anyway, so
        // we'll skip code altogether.

        // In other words: we are doing char alignment here basing on suggestion
        // that count of zero-'terminators' is a number of bytes in one symbol
        // for selected charset (clipboard format). It is not complitly true for
        // multibyte coding like UTF-8, but helps understand the procedure.
        // "abcde\0" -> "abcde"

        String eoln = (String)nativeEOLNs.get(lFormat);
        Integer terminators = (Integer)nativeTerminators.get(lFormat);
        int count;
        if (terminators != null) {
            int numTerminators = terminators.intValue();
search:
            for (count = 0; count < (bytes.length - numTerminators + 1); count += numTerminators) {
                for (int i = count; i < count + numTerminators; i++) {
                    if (bytes[i] != 0x0) {
                        continue search;
                    }
                }
                // found terminators
                break search;
            }
        } else {
            count = bytes.length;
        }

        // Decode text to chars. Don't include any terminators.
        String converted = new String(bytes, 0, count, charset);

        // Search and replace EOLN. Note that if EOLN is "\n", then we
        // never added an entry to nativeEOLNs anyway, so we'll skip this
        // code altogether.
        // Count of NUL-terminators and EOLN coding are platform-specific and
        // loaded from flavormap.properties file
        // windows: "abc\r\nde" -> "abc\nde"

        if (eoln != null) {

            /* Fix for 4463560: replace EOLNs symbol-by-symbol instead
             * of using buf.replace()
             */

            char[] buf = converted.toCharArray();
            char[] eoln_arr = eoln.toCharArray();
            converted = null;
            int j = 0;
            boolean match;

            for (int i = 0; i < buf.length; ) {
                // Catch last few bytes
                if (i + eoln_arr.length > buf.length) {
                    buf[j++] = buf[i++];
                    continue;
                }

                match = true;
                for (int k = 0, l = i; k < eoln_arr.length; k++, l++) {
                    if (eoln_arr[k] != buf[l]) {
                        match = false;
                        break;
                    }
                }
                if (match) {
                    buf[j++] = '\n';
                    i += eoln_arr.length;
                } else {
                    buf[j++] = buf[i++];
                }
            }
            converted = new String(buf, 0, j);
        }

        return converted;
    }


    /**
     * Primary translation function for translating a Transferable into
     * a byte array, given a source DataFlavor and target format.
     */
    public byte[] translateTransferable(Transferable contents,
                                        DataFlavor flavor,
                                        long format) throws IOException
    {
        // Obtain the transfer data in the source DataFlavor.
        //
        // Note that we special case DataFlavor.plainTextFlavor because
        // StringSelection supports this flavor incorrectly -- instead of
        // returning an InputStream as the DataFlavor representation class
        // states, it returns a Reader. Instead of using this broken
        // functionality, we request the data in stringFlavor (the other
        // DataFlavor which StringSelection supports) and use the String
        // translator.
        Object obj;
        boolean stringSelectionHack;
        try {
            obj = contents.getTransferData(flavor);
            if (obj == null) {
                return null;
            }
            if (flavor.equals(DataFlavor.plainTextFlavor) &&
                !(obj instanceof InputStream))
            {
                obj = contents.getTransferData(DataFlavor.stringFlavor);
                if (obj == null) {
                    return null;
                }
                stringSelectionHack = true;
            } else {
                stringSelectionHack = false;
            }
        } catch (UnsupportedFlavorException e) {
            throw new IOException(e.getMessage());
        }

        // Source data is a String. Search-and-replace EOLN. Encode into the
        // target format. Append terminating NUL bytes.
        if (stringSelectionHack ||
            (String.class.equals(flavor.getRepresentationClass()) &&
             isFlavorCharsetTextType(flavor) && isTextFormat(format))) {

            String str = removeSuspectedData(flavor, contents, (String)obj);

            return translateTransferableString(
                str,
                format);

        // Source data is a Reader. Convert to a String and recur. In the
        // future, we may want to rewrite this so that we encode on demand.
        } else if (flavor.isRepresentationClassReader()) {
            if (!(isFlavorCharsetTextType(flavor) && isTextFormat(format))) {
                throw new IOException
                    ("cannot transfer non-text data as Reader");
            }

            StringBuffer buf = new StringBuffer();
            try (Reader r = (Reader)obj) {
                int c;
                while ((c = r.read()) != -1) {
                    buf.append((char)c);
                }
            }

            return translateTransferableString(
                buf.toString(),
                format);

        // Source data is a CharBuffer. Convert to a String and recur.
        } else if (flavor.isRepresentationClassCharBuffer()) {
            if (!(isFlavorCharsetTextType(flavor) && isTextFormat(format))) {
                throw new IOException
                    ("cannot transfer non-text data as CharBuffer");
            }

            CharBuffer buffer = (CharBuffer)obj;
            int size = buffer.remaining();
            char[] chars = new char[size];
            buffer.get(chars, 0, size);

            return translateTransferableString(
                new String(chars),
                format);

        // Source data is a char array. Convert to a String and recur.
        } else if (char[].class.equals(flavor.getRepresentationClass())) {
            if (!(isFlavorCharsetTextType(flavor) && isTextFormat(format))) {
                throw new IOException
                    ("cannot transfer non-text data as char array");
            }

            return translateTransferableString(
                new String((char[])obj),
                format);

        // Source data is a ByteBuffer. For arbitrary flavors, simply return
        // the array. For text flavors, decode back to a String and recur to
        // reencode according to the requested format.
        } else if (flavor.isRepresentationClassByteBuffer()) {
            ByteBuffer buffer = (ByteBuffer)obj;
            int size = buffer.remaining();
            byte[] bytes = new byte[size];
            buffer.get(bytes, 0, size);

            if (isFlavorCharsetTextType(flavor) && isTextFormat(format)) {
                String sourceEncoding = DataTransferer.getTextCharset(flavor);
                return translateTransferableString(
                    new String(bytes, sourceEncoding),
                    format);
            } else {
                return bytes;
            }

        // Source data is a byte array. For arbitrary flavors, simply return
        // the array. For text flavors, decode back to a String and recur to
        // reencode according to the requested format.
        } else if (byte[].class.equals(flavor.getRepresentationClass())) {
            byte[] bytes = (byte[])obj;

            if (isFlavorCharsetTextType(flavor) && isTextFormat(format)) {
                String sourceEncoding = DataTransferer.getTextCharset(flavor);
                return translateTransferableString(
                    new String(bytes, sourceEncoding),
                    format);
            } else {
                return bytes;
            }
        // Source data is Image
        } else if (DataFlavor.imageFlavor.equals(flavor)) {
            if (!isImageFormat(format)) {
                throw new IOException("Data translation failed: " +
                                      "not an image format");
            }

            Image image = (Image)obj;
            byte[] bytes = imageToPlatformBytes(image, format);

            if (bytes == null) {
                throw new IOException("Data translation failed: " +
                    "cannot convert java image to native format");
            }
            return bytes;
        }

        byte[] theByteArray = null;

        // Target data is a file list. Source data must be a
        // java.util.List which contains java.io.File or String instances.
        if (isFileFormat(format)) {
            if (!DataFlavor.javaFileListFlavor.equals(flavor)) {
                throw new IOException("data translation failed");
            }

            final List list = (List)obj;

            final ProtectionDomain userProtectionDomain = getUserProtectionDomain(contents);

            final ArrayList<String> fileList = castToFiles(list, userProtectionDomain);

            try (ByteArrayOutputStream bos = convertFileListToBytes(fileList)) {
                theByteArray = bos.toByteArray();
            }

        // Target data is a URI list. Source data must be a
        // java.util.List which contains java.io.File or String instances.
        } else if (isURIListFormat(format)) {
            if (!DataFlavor.javaFileListFlavor.equals(flavor)) {
                throw new IOException("data translation failed");
            }
            String nat = getNativeForFormat(format);
            String targetCharset = null;
            if (nat != null) {
                try {
                    targetCharset = new DataFlavor(nat).getParameter("charset");
                } catch (ClassNotFoundException cnfe) {
                    throw new IOException(cnfe);
                }
            }
            if (targetCharset == null) {
                targetCharset = "UTF-8";
            }
            final List list = (List)obj;
            final ProtectionDomain userProtectionDomain = getUserProtectionDomain(contents);
            final ArrayList<String> fileList = castToFiles(list, userProtectionDomain);
            final ArrayList<String> uriList = new ArrayList<String>(fileList.size());
            for (String fileObject : fileList) {
                final URI uri = new File(fileObject).toURI();
                // Some implementations are fussy about the number of slashes (file:///path/to/file is best)
                try {
                    uriList.add(new URI(uri.getScheme(), "", uri.getPath(), uri.getFragment()).toString());
                } catch (URISyntaxException uriSyntaxException) {
                    throw new IOException(uriSyntaxException);
                  }
              }

            byte[] eoln = "\r\n".getBytes(targetCharset);

            try (ByteArrayOutputStream bos = new ByteArrayOutputStream()) {
                for (int i = 0; i < uriList.size(); i++) {
                    byte[] bytes = uriList.get(i).getBytes(targetCharset);
                    bos.write(bytes, 0, bytes.length);
                    bos.write(eoln, 0, eoln.length);
                }
                theByteArray = bos.toByteArray();
            }

        // Source data is an InputStream. For arbitrary flavors, just grab th…

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