/*

 * Copyright (c) 2005, 2016, 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 com.sun.tools.javac.api;

import java.io.IOException;

import java.nio.CharBuffer;

import java.util.*;

import java.util.concurrent.Callable;

import java.util.concurrent.atomic.AtomicBoolean;

import javax.annotation.processing.Processor;

import javax.lang.model.element.Element;

import javax.lang.model.element.ElementKind;

import javax.lang.model.element.TypeElement;

import javax.lang.model.util.ElementFilter;

import javax.tools.*;

import javax.tools.JavaFileObject.Kind;

import com.sun.source.tree.*;

import com.sun.tools.javac.code.*;

import com.sun.tools.javac.code.Symbol.ClassSymbol;

import com.sun.tools.javac.code.Symbol.ModuleSymbol;

import com.sun.tools.javac.code.Symbol.PackageSymbol;

import com.sun.tools.javac.comp.*;

import com.sun.tools.javac.file.BaseFileManager;

import com.sun.tools.javac.main.*;

import com.sun.tools.javac.main.JavaCompiler;

import com.sun.tools.javac.parser.Parser;

import com.sun.tools.javac.parser.ParserFactory;

import com.sun.tools.javac.processing.AnnotationProcessingError;

import com.sun.tools.javac.tree.*;

import com.sun.tools.javac.tree.JCTree.JCClassDecl;

import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;

import com.sun.tools.javac.tree.JCTree.JCModuleDecl;

import com.sun.tools.javac.tree.JCTree.Tag;

import com.sun.tools.javac.util.*;

import com.sun.tools.javac.util.DefinedBy.Api;

import com.sun.tools.javac.util.List;

import com.sun.tools.javac.util.Log.PrefixKind;

import com.sun.tools.javac.util.Log.WriterKind;

/**

 * Provides access to functionality specific to the JDK Java Compiler, javac.

 *

 * <p><b>This is NOT part of any supported API.

 * If you write code that depends on this, you do so at your own

 * risk.  This code and its internal interfaces are subject to change

 * or deletion without notice.</b></p>

 *

 * @author Peter von der Ahé

 * @author Jonathan Gibbons

 */

public class JavacTaskImpl extends BasicJavacTask {

    private final Arguments args;

    private JavaCompiler compiler;

    private JavaFileManager fileManager;

    private Locale locale;

    private Map<JavaFileObject, JCCompilationUnit> notYetEntered;

    private ListBuffer<Env<AttrContext>> genList;

    private final AtomicBoolean used = new AtomicBoolean();

    private Iterable<? extends Processor> processors;

    protected JavacTaskImpl(Context context) {

        super(context, true);

        args = Arguments.instance(context);

        fileManager = context.get(JavaFileManager.class);

    }

    @Override @DefinedBy(Api.COMPILER)

    public Boolean call() {

        return doCall().isOK();

    }

    /* Internal version of call exposing Main.Result. */

    public Main.Result doCall() {

        try {

            return handleExceptions(() -> {

                prepareCompiler(false);

                if (compiler.errorCount() > 0)

                    return Main.Result.ERROR;

                compiler.compile(args.getFileObjects(), args.getClassNames(), processors);

                return (compiler.errorCount() > 0) ? Main.Result.ERROR : Main.Result.OK; // FIXME?

            }, Main.Result.SYSERR, Main.Result.ABNORMAL);

        } finally {

            try {

                cleanup();

            } catch (ClientCodeException e) {

                throw new RuntimeException(e.getCause());

            }

        }

    }

    @Override @DefinedBy(Api.COMPILER)

    public void setProcessors(Iterable<? extends Processor> processors) {

        Objects.requireNonNull(processors);

        // not mt-safe

        if (used.get())

            throw new IllegalStateException();

        this.processors = processors;

    }

    @Override @DefinedBy(Api.COMPILER)

    public void setLocale(Locale locale) {

        if (used.get())

            throw new IllegalStateException();

        this.locale = locale;

    }

    private <T> T handleExceptions(Callable<T> c, T sysErrorResult, T abnormalErrorResult) {

        try {

            return c.call();

        } catch (FatalError ex) {

            Log log = Log.instance(context);

            Options options = Options.instance(context);

            log.printRawLines(ex.getMessage());

            if (ex.getCause() != null && options.isSet("dev")) {

                ex.getCause().printStackTrace(log.getWriter(WriterKind.NOTICE));

            }

            return sysErrorResult;

        } catch (AnnotationProcessingError | ClientCodeException e) {

            // AnnotationProcessingError is thrown from JavacProcessingEnvironment,

            // to forward errors thrown from an annotation processor

            // ClientCodeException is thrown from ClientCodeWrapper,

            // to forward errors thrown from user-supplied code for Compiler API

            // as specified by javax.tools.JavaCompiler#getTask

            // and javax.tools.JavaCompiler.CompilationTask#call

            throw new RuntimeException(e.getCause());

        } catch (PropagatedException e) {

            throw e.getCause();

        } catch (IllegalStateException e) {

            throw e;

        } catch (Exception | Error ex) {

            // Nasty.  If we've already reported an error, compensate

            // for buggy compiler error recovery by swallowing thrown

            // exceptions.

            if (compiler == null || compiler.errorCount() == 0

                    || Options.instance(context).isSet("dev")) {

                Log log = Log.instance(context);

                log.printLines(PrefixKind.JAVAC, "msg.bug", JavaCompiler.version());

                ex.printStackTrace(log.getWriter(WriterKind.NOTICE));

            }

            return abnormalErrorResult;

        }

    }

    private void prepareCompiler(boolean forParse) {

        if (used.getAndSet(true)) {

            if (compiler == null)

                throw new PropagatedException(new IllegalStateException());

        } else {

            args.validate();

            //initialize compiler's default locale

            context.put(Locale.class, locale);

            // hack

            JavacMessages messages = context.get(JavacMessages.messagesKey);

            if (messages != null && !messages.getCurrentLocale().equals(locale))

                messages.setCurrentLocale(locale);

            initPlugins(args.getPluginOpts());

            initDocLint(args.getDocLintOpts());

            // init JavaCompiler and queues

            compiler = JavaCompiler.instance(context);

            compiler.keepComments = true;

            compiler.genEndPos = true;

            notYetEntered = new HashMap<>();

            if (forParse) {

                for (JavaFileObject file: args.getFileObjects())

                    notYetEntered.put(file, null);

                genList = new ListBuffer<>();

            }

        }

    }

    <T> String toString(Iterable<T> items, String sep) {

        String currSep = "";

        StringBuilder sb = new StringBuilder();

        for (T item: items) {

            sb.append(currSep);

            sb.append(item.toString());

            currSep = sep;

        }

        return sb.toString();

    }

    void cleanup() {

        if (compiler != null)

            compiler.close();

        if (fileManager instanceof BaseFileManager && ((BaseFileManager) fileManager).autoClose) {

            try {

                fileManager.close();

            } catch (IOException ignore) {

            }

        }

        compiler = null;

        context = null;

        notYetEntered = null;

    }

    @Override @DefinedBy(Api.COMPILER_TREE)

    public Iterable<? extends CompilationUnitTree> parse() {

        return handleExceptions(this::parseInternal, List.nil(), List.nil());

    }

    private Iterable<? extends CompilationUnitTree> parseInternal() {

        try {

            prepareCompiler(true);

            List<JCCompilationUnit> units = compiler.parseFiles(args.getFileObjects());

            for (JCCompilationUnit unit: units) {

                JavaFileObject file = unit.getSourceFile();

                if (notYetEntered.containsKey(file))

                    notYetEntered.put(file, unit);

            }

            return units;

        }

        finally {

            parsed = true;

            if (compiler != null && compiler.log != null)

                compiler.log.flush();

        }

    }

    private boolean parsed = false;

    /**

     * Translate all the abstract syntax trees to elements.

     *

     * @return a list of elements corresponding to the top level

     * classes in the abstract syntax trees

     */

    public Iterable<? extends Element> enter() {

        return enter(null);

    }

    /**

     * Translate the given abstract syntax trees to elements.

     *

     * @param trees a list of abstract syntax trees.

     * @return a list of elements corresponding to the top level

     * classes in the abstract syntax trees

     */

    public Iterable<? extends Element> enter(Iterable<? extends CompilationUnitTree> trees)

    {

        if (trees == null && notYetEntered != null && notYetEntered.isEmpty())

            return List.nil();

        boolean wasInitialized = compiler != null;

        prepareCompiler(true);

        ListBuffer<JCCompilationUnit> roots = null;

        if (trees == null) {

            // If there are still files which were specified to be compiled

            // (i.e. in fileObjects) but which have not yet been entered,

            // then we make sure they have been parsed and add them to the

            // list to be entered.

            if (notYetEntered.size() > 0) {

                if (!parsed)

                    parseInternal(); // TODO would be nice to specify files needed to be parsed

                for (JavaFileObject file: args.getFileObjects()) {

                    JCCompilationUnit unit = notYetEntered.remove(file);

                    if (unit != null) {

                        if (roots == null)

                            roots = new ListBuffer<>();

                        roots.append(unit);

                    }

                }

                notYetEntered.clear();

            }

        }

        else {

            for (CompilationUnitTree cu : trees) {

                if (cu instanceof JCCompilationUnit) {

                    if (roots == null)

                        roots = new ListBuffer<>();

                    roots.append((JCCompilationUnit)cu);

                    notYetEntered.remove(cu.getSourceFile());

                }

                else

                    throw new IllegalArgumentException(cu.toString());

            }

        }

        if (roots == null) {

            if (trees == null && !wasInitialized) {

                compiler.initModules(List.nil());

            }

            return List.nil();

        }

        List<JCCompilationUnit> units = compiler.initModules(roots.toList());

        try {

            units = compiler.enterTrees(units);

            if (notYetEntered.isEmpty())

                compiler.processAnnotations(units);

            ListBuffer<Element> elements = new ListBuffer<>();

            for (JCCompilationUnit unit : units) {

                boolean isPkgInfo = unit.sourcefile.isNameCompatible("package-info",

                                                                     JavaFileObject.Kind.SOURCE);

                if (isPkgInfo) {

                    elements.append(unit.packge);

                } else {

                    for (JCTree node : unit.defs) {

                        if (node.hasTag(JCTree.Tag.CLASSDEF)) {

                            JCClassDecl cdef = (JCClassDecl) node;

                            if (cdef.sym != null) // maybe null if errors in anno processing

                                elements.append(cdef.sym);

                        } else if (node.hasTag(JCTree.Tag.MODULEDEF)) {

                            JCModuleDecl mdef = (JCModuleDecl) node;

                            if (mdef.sym != null)

                                elements.append(mdef.sym);

                        }

                    }

                }

            }

            return elements.toList();

        }

        finally {

            compiler.log.flush();

        }

    }

    @Override @DefinedBy(Api.COMPILER_TREE)

    public Iterable<? extends Element> analyze() {

        return handleExceptions(() -> analyze(null), List.nil(), List.nil());

    }

    /**

     * Complete all analysis on the given classes.

     * This can be used to ensure that all compile time errors are reported.

     * The classes must have previously been returned from {@link #enter}.

     * If null is specified, all outstanding classes will be analyzed.

     *

     * @param classes a list of class elements

     * @return the elements that were analyzed

     */

    // This implementation requires that we open up privileges on JavaCompiler.

    // An alternative implementation would be to move this code to JavaCompiler and

    // wrap it here

    public Iterable<? extends Element> analyze(Iterable<? extends Element> classes) {

        enter(null);  // ensure all classes have been entered

        final ListBuffer<Element> results = new ListBuffer<>();

        try {

            if (classes == null) {

                handleFlowResults(compiler.flow(compiler.attribute(compiler.todo)), results);

            } else {

                Filter f = new Filter() {

                    @Override

                    public void process(Env<AttrContext> env) {

                        handleFlowResults(compiler.flow(compiler.attribute(env)), results);

                    }

                };

                f.run(compiler.todo, classes);

            }

        } finally {

            compiler.log.flush();

        }

        return results;

    }

    // where

        private void handleFlowResults(Queue<Env<AttrContext>> queue, ListBuffer<Element> elems) {

            for (Env<AttrContext> env: queue) {

                switch (env.tree.getTag()) {

                    case CLASSDEF:

                        JCClassDecl cdef = (JCClassDecl) env.tree;

                        if (cdef.sym != null)

                            elems.append(cdef.sym);

                        break;

                    case MODULEDEF:

                        JCModuleDecl mod = (JCModuleDecl) env.tree;

                        if (mod.sym != null)

                            elems.append(mod.sym);

                        break;

                    case PACKAGEDEF:

                        JCCompilationUnit unit = env.toplevel;

                        if (unit.packge != null)

                            elems.append(unit.packge);

                        break;

                }

            }

            genList.addAll(queue);

        }

    @Override @DefinedBy(Api.COMPILER_TREE)

    public Iterable<? extends JavaFileObject> generate() {

        return handleExceptions(() -> generate(null), List.nil(), List.nil());

    }

    /**

     * Generate code corresponding to the given classes.

     * The classes must have previously been returned from {@link #enter}.

     * If there are classes outstanding to be analyzed, that will be done before

     * any classes are generated.

     * If null is specified, code will be generated for all outstanding classes.

     *

     * @param classes a list of class elements

     * @return the files that were generated

     */

    public Iterable<? extends JavaFileObject> generate(Iterable<? extends Element> classes) {

        final ListBuffer<JavaFileObject> results = new ListBuffer<>();

        try {

            analyze(null);  // ensure all classes have been parsed, entered, and analyzed

            if (classes == null) {

                compiler.generate(compiler.desugar(genList), results);

                genList.clear();

            }

            else {

                Filter f = new Filter() {

                        @Override

                        public void process(Env<AttrContext> env) {

                            compiler.generate(compiler.desugar(ListBuffer.of(env)), results);

                        }

                    };

                f.run(genList, classes);

            }

            if (genList.isEmpty()) {

                compiler.reportDeferredDiagnostics();

                cleanup();

            }

        }

        finally {

            if (compiler != null)

                compiler.log.flush();

        }

        return results;

    }

    public Iterable<? extends Tree> pathFor(CompilationUnitTree unit, Tree node) {

        return TreeInfo.pathFor((JCTree) node, (JCTree.JCCompilationUnit) unit).reverse();

    }

    public void ensureEntered() {

        args.allowEmpty();

        enter(null);

    }

    abstract class Filter {

        void run(Queue<Env<AttrContext>> list, Iterable<? extends Element> elements) {

            Set<Element> set = new HashSet<>();

            for (Element item: elements) {

                set.add(item);

            }

            ListBuffer<Env<AttrContext>> defer = new ListBuffer<>();

            while (list.peek() != null) {

                Env<AttrContext> env = list.remove();

                Symbol test = null;

                if (env.tree.hasTag(Tag.MODULEDEF)) {

                    test = ((JCModuleDecl) env.tree).sym;

                } else if (env.tree.hasTag(Tag.PACKAGEDEF)) {

                    test = env.toplevel.packge;

                } else {

                    ClassSymbol csym = env.enclClass.sym;

                    if (csym != null)

                        test = csym.outermostClass();

                }

                if (test != null && set.contains(test))

                    process(env);

                else

                    defer = defer.append(env);

            }

            list.addAll(defer);

        }

        abstract void process(Env<AttrContext> env);

    }