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 * 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,
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 *
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package com.sun.tools.jdeps;

import java.io.IOException;
import java.io.PrintWriter;
import java.lang.module.ModuleDescriptor;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
import java.util.stream.Collectors;
import java.util.stream.Stream;

/**
 * Analyze module dependences and any reference to JDK internal APIs.
 * It can apply transition reduction on the resulting module graph.
 *
 * The result prints one line per module it depends on
 * one line per JDK internal API package it references:
 *     $MODULE[/$PACKAGE]
 *
 */
public class ModuleExportsAnalyzer extends DepsAnalyzer {
    // source archive to its dependences and JDK internal APIs it references
    private final Map<Archive, Map<Archive,Set<String>>> deps = new HashMap<>();
    private final Map<String, Set<String>> missingDeps = new HashMap<>();
    private final boolean showInternals;
    private final boolean reduced;
    private final PrintWriter writer;
    private final String separator;
    public ModuleExportsAnalyzer(JdepsConfiguration config,
                                 JdepsFilter filter,
                                 boolean showInternals,
                                 boolean reduced,
                                 PrintWriter writer,
                                 String separator) {
        super(config, filter, null,
              Analyzer.Type.PACKAGE,
              false /* all classes */);
        this.showInternals = showInternals;
        this.reduced = reduced;
        this.writer = writer;
        this.separator = separator;
    }

    public boolean run(int maxDepth, boolean ignoreMissingDeps) throws IOException {
        // use compile time view so that the entire archive on classpath is analyzed
        boolean rc = super.run(true, maxDepth);

        // A visitor to record the module-level dependences as well as
        // use of internal APIs
        Analyzer.Visitor visitor = (origin, originArchive, target, targetArchive) -> {
            Set<String> internals =
                deps.computeIfAbsent(originArchive, _k -> new HashMap<>())
                    .computeIfAbsent(targetArchive, _k -> new HashSet<>());

            Module module = targetArchive.getModule();
            if (showInternals && originArchive.getModule() != module &&
                    module.isNamed() && !module.isExported(target, module.name())) {
                // use of internal APIs
                internals.add(target);
            }
            if (!ignoreMissingDeps && Analyzer.notFound(targetArchive)) {
                Set<String> notFound =
                    missingDeps.computeIfAbsent(origin, _k -> new HashSet<>());
                notFound.add(target);
            }
        };

        // visit the dependences
        archives.stream()
            .filter(analyzer::hasDependences)
            .sorted(Comparator.comparing(Archive::getName))
            .forEach(archive -> analyzer.visitDependences(archive, visitor));

        // error if any missing dependence
        if (!rc || !missingDeps.isEmpty()) {
            return false;
        }

        Map<Module, Set<String>> internalPkgs = internalPackages();
        Set<Module> modules = modules();
        if (showInternals) {
            // print modules and JDK internal API dependences
            Stream.concat(modules.stream(), internalPkgs.keySet().stream())
                    .sorted(Comparator.comparing(Module::name))
                    .distinct()
                    .forEach(m -> {
                        if (internalPkgs.containsKey(m)) {
                            internalPkgs.get(m)
                                .forEach(pn -> writer.format("   %s/%s%s", m, pn, separator));
                        } else {
                            writer.format("   %s%s", m, separator);
                        }
                    });
        } else {
            // print module dependences
            writer.println(modules.stream().map(Module::name).sorted()
                                  .collect(Collectors.joining(separator)));
        }
        return rc;
    }

    /*
     * Prints missing dependences
     */
    void visitMissingDeps(Analyzer.Visitor visitor) {
        archives.stream()
            .filter(analyzer::hasDependences)
            .sorted(Comparator.comparing(Archive::getName))
            .filter(m -> analyzer.requires(m).anyMatch(Analyzer::notFound))
            .forEach(m -> {
                analyzer.visitDependences(m, visitor, Analyzer.Type.VERBOSE, Analyzer::notFound);
            });
    }

    private Set<Module> modules() {
        // build module graph
        ModuleGraphBuilder builder = new ModuleGraphBuilder(configuration);
        Module root = new RootModule();
        builder.addModule(root);
        // find named module dependences
        dependenceStream()
            .flatMap(map -> map.keySet().stream())
            .filter(m -> m.getModule().isNamed() && !configuration.rootModules().contains(m))
            .map(Archive::getModule)
            .forEach(m -> builder.addEdge(root, m));

        // build module dependence graph
        // if reduced is set, apply transition reduction
        Graph<Module> g = reduced ? builder.reduced() : builder.build();
        return g.adjacentNodes(root);
    }

    private Map<Module, Set<String>> internalPackages() {
        Map<Module, Set<String>> internalPkgs = new HashMap<>();
        dependenceStream()
            .flatMap(map -> map.entrySet().stream())
            .filter(e -> e.getValue().size() > 0)
            .forEach(e -> internalPkgs.computeIfAbsent(e.getKey().getModule(),
                                                             _k -> new TreeSet<>())
                                      .addAll(e.getValue()));
        return internalPkgs;
    }

    /*
     * Returns a stream of dependence map from an Archive to the set of JDK
     * internal APIs being used.
     */
    private Stream<Map<Archive, Set<String>>> dependenceStream() {
        return deps.keySet().stream()
                   .filter(source -> !source.getModule().isNamed()
                            || configuration.rootModules().contains(source))
                   .map(deps::get);
    }

    /*
     * RootModule serves as the root node for building the module graph
     */
    private static class RootModule extends Module {
        static final String NAME = "root";
        RootModule() {
            super(NAME, ModuleDescriptor.newModule(NAME).build(), false);
        }
    }

}
