/*
 * Copyright (c) 2005, 2018, 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.TypeElement;
import javax.tools.*;

import com.sun.source.tree.*;
import com.sun.tools.javac.code.*;
import com.sun.tools.javac.code.DeferredCompletionFailureHandler.Handler;
import com.sun.tools.javac.code.Symbol.ClassSymbol;
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.
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.
Author:
Peter von der Ahé, Jonathan Gibbons/**
 * 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 Ah&eacute;
 * @author Jonathan Gibbons
 */
public class JavacTaskImpl extends BasicJavacTask {
    private final Arguments args;
    private JavaCompiler compiler;
    private JavaFileManager fileManager;
    private DeferredCompletionFailureHandler dcfh;
    private Locale locale;
    private Map<JavaFileObject, JCCompilationUnit> notYetEntered;
    private ListBuffer<Env<AttrContext>> genList;
    private final AtomicBoolean used = new AtomicBoolean();
    private Iterable<? extends Processor> processors;
    private ListBuffer<String> addModules = new ListBuffer<>();

    protected JavacTaskImpl(Context context) {
        super(context, true);
        args = Arguments.instance(context);
        fileManager = context.get(JavaFileManager.class);
        dcfh = DeferredCompletionFailureHandler.instance(context);
        dcfh.setHandler(dcfh.userCodeHandler);
    }

    @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, addModules);
                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 addModules(Iterable<String> moduleNames) {
        Objects.requireNonNull(moduleNames);
        // not mt-safe
        if (used.get())
            throw new IllegalStateException();
        for (String m : moduleNames) {
            Objects.requireNonNull(m);
            addModules.add(m);
        }
    }

    @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) {
        Handler prevDeferredHandler = dcfh.setHandler(dcfh.javacCodeHandler);
        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;
        } finally {
            dcfh.setHandler(prevDeferredHandler);
        }
    }

    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) {
                compiler.initProcessAnnotations(processors, args.getFileObjects(), args.getClassNames());
                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.
Returns:
a list of elements corresponding to the top level
classes in the abstract syntax trees/**
     * 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.
Params:
trees – a list of abstract syntax trees.
Returns:
a list of elements corresponding to the top level
classes in the abstract syntax trees/**
     * 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 enter. If null is specified, all outstanding classes will be analyzed. 
Params:
classes – a list of class elements
Returns:
the elements that were analyzed/**
     * 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 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. 
Params:
classes – a list of class elements
Returns:
the files that were generated/**
     * 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);
    }

    
For internal use only.  This method will be
removed without warning.
Params:
expr – the type expression to be analyzed
scope – the scope in which to analyze the type expression
Throws:
IllegalArgumentException – if the type expression of null or empty
Returns:
the type/**
     * For internal use only.  This method will be
     * removed without warning.
     * @param expr the type expression to be analyzed
     * @param scope the scope in which to analyze the type expression
     * @return the type
     * @throws IllegalArgumentException if the type expression of null or empty
     */
    public Type parseType(String expr, TypeElement scope) {
        if (expr == null || expr.equals(""))
            throw new IllegalArgumentException();
        compiler = JavaCompiler.instance(context);
        JavaFileObject prev = compiler.log.useSource(null);
        ParserFactory parserFactory = ParserFactory.instance(context);
        Attr attr = Attr.instance(context);
        try {
            CharBuffer buf = CharBuffer.wrap((expr+"\u0000").toCharArray(), 0, expr.length());
            Parser parser = parserFactory.newParser(buf, false, false, false);
            JCTree tree = parser.parseType();
            return attr.attribType(tree, (Symbol.TypeSymbol)scope);
        } finally {
            compiler.log.useSource(prev);
        }
    }

}