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 * Copyright (c) 2016, 2020, 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 jdk.tools.jlink.internal.plugins;

import java.util.AbstractMap;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.IllformedLocaleException;
import java.util.Locale;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import static java.util.ResourceBundle.Control;
import java.util.Set;
import java.util.function.Predicate;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import java.util.stream.Stream;
import jdk.internal.org.objectweb.asm.ClassReader;
import jdk.tools.jlink.internal.ResourcePrevisitor;
import jdk.tools.jlink.internal.StringTable;
import jdk.tools.jlink.plugin.ResourcePoolModule;
import jdk.tools.jlink.plugin.PluginException;
import jdk.tools.jlink.plugin.ResourcePool;
import jdk.tools.jlink.plugin.ResourcePoolBuilder;
import jdk.tools.jlink.plugin.ResourcePoolEntry;
import jdk.tools.jlink.plugin.Plugin;
import sun.util.cldr.CLDRBaseLocaleDataMetaInfo;
import sun.util.locale.provider.LocaleProviderAdapter;
import sun.util.locale.provider.LocaleProviderAdapter.Type;
import sun.util.locale.provider.ResourceBundleBasedAdapter;

Plugin to explicitly specify the locale data included in jdk.localedata
module. This plugin provides a jlink command line option "--include-locales"
with an argument. The argument is a list of BCP 47 language tags separated
by a comma. E.g.,
 "jlink --include-locales en,ja,*-IN"
This option will include locale data for all available English and Japanese
languages, and ones for the country of India. All other locale data are
filtered out on the image creation.
Here are a few assumptions:
 0. All locale data in java.base are unconditionally included.
 1. All the selective locale data are in jdk.localedata module
 2. Their package names are constructed by appending ".ext" to
    the corresponding ones in java.base module.
 3. Available locales string in LocaleDataMetaInfo class should
    start with at least one white space character, e.g., " ar ar-EG ..."
                                                          ^
/**
 * Plugin to explicitly specify the locale data included in jdk.localedata
 * module. This plugin provides a jlink command line option "--include-locales"
 * with an argument. The argument is a list of BCP 47 language tags separated
 * by a comma. E.g.,
 *
 *  "jlink --include-locales en,ja,*-IN"
 *
 * This option will include locale data for all available English and Japanese
 * languages, and ones for the country of India. All other locale data are
 * filtered out on the image creation.
 *
 * Here are a few assumptions:
 *
 *  0. All locale data in java.base are unconditionally included.
 *  1. All the selective locale data are in jdk.localedata module
 *  2. Their package names are constructed by appending ".ext" to
 *     the corresponding ones in java.base module.
 *  3. Available locales string in LocaleDataMetaInfo class should
 *     start with at least one white space character, e.g., " ar ar-EG ..."
 *                                                           ^
 */
public final class IncludeLocalesPlugin implements Plugin, ResourcePrevisitor {

    public static final String NAME = "include-locales";
    private static final String MODULENAME = "jdk.localedata";
    private static final Set<String> LOCALEDATA_PACKAGES = Set.of(
        "sun.text.resources.cldr.ext",
        "sun.text.resources.ext",
        "sun.util.resources.cldr.ext",
        "sun.util.resources.cldr.provider",
        "sun.util.resources.ext",
        "sun.util.resources.provider");
    private static final String METAINFONAME = "LocaleDataMetaInfo";
    private static final List<String> META_FILES = List.of(
        ".+module-info.class",
        ".+LocaleDataProvider.class",
        ".+" + METAINFONAME + ".class");
    private static final List<String> INCLUDE_LOCALE_FILES = List.of(
        ".+sun/text/resources/ext/[^_]+_",
        ".+sun/util/resources/ext/[^_]+_",
        ".+sun/text/resources/cldr/ext/[^_]+_",
        ".+sun/util/resources/cldr/ext/[^_]+_");
    private Predicate<String> predicate;
    private String userParam;
    private List<Locale.LanguageRange> priorityList;
    private List<Locale> available;
    private List<String> filtered;

    private static final ResourceBundleBasedAdapter CLDR_ADAPTER =
        (ResourceBundleBasedAdapter)LocaleProviderAdapter.forType(Type.CLDR);
    private static final Map<Locale, String[]> CLDR_PARENT_LOCALES =
        new CLDRBaseLocaleDataMetaInfo().parentLocales();

    // Equivalent map
    private static final Map<String, List<String>> EQUIV_MAP =
        Stream.concat(
            // COMPAT equivalence
            Map.of(
                "zh-Hans", List.of("zh-Hans", "zh-CN", "zh-SG"),
                "zh-Hant", List.of("zh-Hant", "zh-HK", "zh-MO", "zh-TW"))
                .entrySet()
                .stream(),

            // CLDR parent locales
            CLDR_PARENT_LOCALES.entrySet().stream()
                .map(entry -> {
                    String parent = entry.getKey().toLanguageTag();
                    List<String> children = new ArrayList<>();
                    children.add(parent);

                    Arrays.stream(entry.getValue())
                        .filter(child -> !child.isEmpty())
                        .flatMap(child ->
                            Stream.concat(
                                Arrays.stream(CLDR_PARENT_LOCALES.getOrDefault(
                                    Locale.forLanguageTag(child), new String[0]))
                                        .filter(grandchild -> !grandchild.isEmpty()),
                                List.of(child).stream()))
                        .distinct()
                        .forEach(children::add);
                    return new AbstractMap.SimpleEntry<String, List<String>>(parent, children);
                })
        ).collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));

    // Special COMPAT provider locales
    private static final String jaJPJPTag = "ja-JP-JP";
    private static final String noNONYTag = "no-NO-NY";
    private static final String thTHTHTag = "th-TH-TH";
    private static final Locale jaJPJP = new Locale("ja", "JP", "JP");
    private static final Locale noNONY = new Locale("no", "NO", "NY");
    private static final Locale thTHTH = new Locale("th", "TH", "TH");

    @Override
    public String getName() {
        return NAME;
    }

    @Override
    public ResourcePool transform(ResourcePool in, ResourcePoolBuilder out) {
        in.transformAndCopy((resource) -> {
            if (resource.moduleName().equals(MODULENAME)) {
                String path = resource.path();
                resource = predicate.test(path) ? resource: null;
                if (resource != null &&
                    resource.type().equals(ResourcePoolEntry.Type.CLASS_OR_RESOURCE)) {
                    byte[] bytes = resource.contentBytes();
                    ClassReader cr = new ClassReader(bytes);
                    if (Arrays.stream(cr.getInterfaces())
                        .anyMatch(i -> i.contains(METAINFONAME)) &&
                        stripUnsupportedLocales(bytes, cr)) {
                        resource = resource.copyWithContent(bytes);
                    }
                }
            }
            return resource;
        }, out);

        return out.build();
    }

    @Override
    public Category getType() {
        return Category.FILTER;
    }

    @Override
    public String getDescription() {
        return PluginsResourceBundle.getDescription(NAME);
    }

    @Override
    public boolean hasArguments() {
        return true;
    }

    @Override
    public String getArgumentsDescription() {
       return PluginsResourceBundle.getArgument(NAME);
    }

    @Override
    public void configure(Map<String, String> config) {
        userParam = config.get(NAME);

        try {
            priorityList = Locale.LanguageRange.parse(userParam, EQUIV_MAP);
        } catch (IllegalArgumentException iae) {
            throw new IllegalArgumentException(String.format(
                PluginsResourceBundle.getMessage(NAME + ".invalidtag"),
                    iae.getMessage().replaceFirst("^range=", "")));
        }
    }

    @Override
    public void previsit(ResourcePool resources, StringTable strings) {
        final Pattern p = Pattern.compile(".*((Data_)|(Names_))(?<tag>.*)\\.class");
        Optional<ResourcePoolModule> optMod = resources.moduleView().findModule(MODULENAME);

        // jdk.localedata module validation
        if (optMod.isPresent()) {
            ResourcePoolModule module = optMod.get();
            Set<String> packages = module.packages();
            if (!packages.containsAll(LOCALEDATA_PACKAGES)) {
                throw new PluginException(PluginsResourceBundle.getMessage(NAME + ".missingpackages") +
                    LOCALEDATA_PACKAGES.stream()
                        .filter(pn -> !packages.contains(pn))
                        .collect(Collectors.joining(",\n\t")));
            }

            available = Stream.concat(module.entries()
                                        .map(md -> p.matcher(md.path()))
                                        .filter(m -> m.matches())
                                        .map(m -> m.group("tag").replaceAll("_", "-")),
                                    Stream.concat(Stream.of(jaJPJPTag), Stream.of(thTHTHTag)))
                .distinct()
                .sorted()
                .map(IncludeLocalesPlugin::tagToLocale)
                .collect(Collectors.toList());
        } else {
            // jdk.localedata is not added.
            throw new PluginException(PluginsResourceBundle.getMessage(NAME + ".localedatanotfound"));
        }

        filtered = filterLocales(available);

        if (filtered.isEmpty()) {
            throw new PluginException(
                String.format(PluginsResourceBundle.getMessage(NAME + ".nomatchinglocales"), userParam));
        }

        List<String> value = Stream.concat(
                META_FILES.stream(),
                filtered.stream().flatMap(s -> includeLocaleFilePatterns(s).stream()))
            .map(s -> "regex:" + s)
            .collect(Collectors.toList());

        predicate = ResourceFilter.includeFilter(value);
    }

    private List<String> includeLocaleFilePatterns(String tag) {
        // Ignore extension variations
        if (tag.matches(".+-[a-z]-.+")) {
            return List.of();
        }

        List<String> files = new ArrayList<>(includeLocaleFiles(tag.replaceAll("-", "_")));

        // Add Thai BreakIterator related data files
        if (tag.equals("th")) {
            files.add(".+sun/text/resources/ext/thai_dict");
            files.add(".+sun/text/resources/ext/[^_]+BreakIteratorData_th");
        }

        // Add Taiwan resource bundles for Hong Kong
        if (tag.equals("zh-HK")) {
            files.addAll(includeLocaleFiles("zh_TW"));
        }

        return files;
    }

    private List<String> includeLocaleFiles(String localeStr) {
        return INCLUDE_LOCALE_FILES.stream()
            .map(s -> s + localeStr + ".class")
            .collect(Collectors.toList());
    }

    private boolean stripUnsupportedLocales(byte[] bytes, ClassReader cr) {
        boolean[] modified = new boolean[1];

        IntStream.range(1, cr.getItemCount())
            .map(item -> cr.getItem(item))
            .forEach(itemIndex -> {
                if (bytes[itemIndex - 1] == 1 &&         // UTF-8
                    bytes[itemIndex + 2] == (byte)' ') { // fast check for leading space
                    int length = cr.readUnsignedShort(itemIndex);
                    byte[] b = new byte[length];
                    System.arraycopy(bytes, itemIndex + 2, b, 0, length);
                    if (filterOutUnsupportedTags(b)) {
                        // copy back
                        System.arraycopy(b, 0, bytes, itemIndex + 2, length);
                        modified[0] = true;
                    }
                }
            });

        return modified[0];
    }

    private boolean filterOutUnsupportedTags(byte[] b) {
        List<Locale> locales;
        List<String> originalTags = Arrays.asList(new String(b).split(" "));

        try {
            locales = originalTags.stream()
                .filter(tag -> !tag.isEmpty())
                .map(IncludeLocalesPlugin::tagToLocale)
                .collect(Collectors.toList());
        } catch (IllformedLocaleException ile) {
            // Seems not an available locales string literal.
            return false;
        }

        byte[] filteredBytes = filterLocales(locales).stream()
            // Make sure the filtered language tags do exist in the
            // original supported tags for compatibility codes, e.g., "iw"
            .filter(originalTags::contains)
            .collect(Collectors.joining(" "))
            .getBytes();

        if (filteredBytes.length > b.length) {
            throw new InternalError("Size of filtered locales is bigger than the original one");
        }

        System.arraycopy(filteredBytes, 0, b, 0, filteredBytes.length);
        Arrays.fill(b, filteredBytes.length, b.length, (byte)' ');
        return true;
    }

    /*
     * Filter list of locales according to the secified priorityList. Note
     * that returned list of language tags may include extra ones, such as
     * compatibility ones (e.g., "iw" -> "iw", "he").
     */
    private List<String> filterLocales(List<Locale> locales) {
        List<String> ret =
            Locale.filter(priorityList, locales, Locale.FilteringMode.EXTENDED_FILTERING).stream()
                .flatMap(loc -> Stream.concat(Control.getNoFallbackControl(Control.FORMAT_DEFAULT)
                                     .getCandidateLocales("", loc).stream(),
                                CLDR_ADAPTER.getCandidateLocales("", loc).stream()))
                .map(loc ->
                    // Locale.filter() does not preserve the case, which is
                    // significant for "variant" equality. Retrieve the original
                    // locales from the pre-filtered list.
                    locales.stream()
                        .filter(l -> l.toString().equalsIgnoreCase(loc.toString()))
                        .findAny())
                .flatMap(Optional::stream)
                .flatMap(IncludeLocalesPlugin::localeToTags)
                .distinct()
                .collect(Collectors.toList());

        return ret;
    }

    private static final Locale.Builder LOCALE_BUILDER = new Locale.Builder();
    private static Locale tagToLocale(String tag) {
        // ISO3166 compatibility
        tag = tag.replaceFirst("^iw", "he").replaceFirst("^ji", "yi").replaceFirst("^in", "id");

        // Special COMPAT provider locales
        switch (tag) {
            case jaJPJPTag:
                return jaJPJP;
            case noNONYTag:
                return noNONY;
            case thTHTHTag:
                return thTHTH;
            default:
                LOCALE_BUILDER.clear();
                LOCALE_BUILDER.setLanguageTag(tag);
                return LOCALE_BUILDER.build();
        }
    }

    private static Stream<String> localeToTags(Locale loc) {
        Objects.requireNonNull(loc);

        String tag = loc.toLanguageTag();
        List<String> tags = null;

        switch (loc.getLanguage()) {
            // ISO3166 compatibility
            case "iw":
                tags = List.of(tag, tag.replaceFirst("^he", "iw"));
                break;
            case "in":
                tags = List.of(tag, tag.replaceFirst("^id", "in"));
                break;
            case "ji":
                tags = List.of(tag, tag.replaceFirst("^yi", "ji"));
                break;

            // Special COMPAT provider locales
            case "ja":
                if (loc.getCountry() == "JP") {
                    tags = List.of(tag, jaJPJPTag);
                }
                break;
            case "no":
            case "nn":
                if (loc.getCountry() == "NO") {
                    tags = List.of(tag, noNONYTag);
                }
                break;
            case "th":
                if (loc.getCountry() == "TH") {
                    tags = List.of(tag, thTHTHTag);
                }
                break;
        }

        return tags == null ? List.of(tag).stream() : tags.stream();
    }
}