/*

 * Copyright (c) 2005, 2017, 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.processing;

import java.io.Closeable;

import java.io.FileNotFoundException;

import java.io.InputStream;

import java.io.OutputStream;

import java.io.FilterOutputStream;

import java.io.Reader;

import java.io.Writer;

import java.io.FilterWriter;

import java.io.PrintWriter;

import java.io.IOException;

import java.util.*;

import static java.util.Collections.*;

import javax.annotation.processing.*;

import javax.lang.model.SourceVersion;

import javax.lang.model.element.NestingKind;

import javax.lang.model.element.Modifier;

import javax.lang.model.element.Element;

import javax.tools.*;

import javax.tools.JavaFileManager.Location;

import static javax.tools.StandardLocation.SOURCE_OUTPUT;

import static javax.tools.StandardLocation.CLASS_OUTPUT;

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

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

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

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

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

import com.sun.tools.javac.model.JavacElements;

import com.sun.tools.javac.resources.CompilerProperties.Warnings;

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

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

import static com.sun.tools.javac.code.Lint.LintCategory.PROCESSING;

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

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

/**

 * The FilerImplementation class must maintain a number of

 * constraints.  First, multiple attempts to open the same path within

 * the same invocation of the tool results in an IOException being

 * thrown.  For example, trying to open the same source file twice:

 *

 * <pre>

 * createSourceFile("foo.Bar")

 * ...

 * createSourceFile("foo.Bar")

 * </pre>

 *

 * is disallowed as is opening a text file that happens to have

 * the same name as a source file:

 *

 * <pre>

 * createSourceFile("foo.Bar")

 * ...

 * createTextFile(SOURCE_TREE, "foo", new File("Bar"), null)

 * </pre>

 *

 * <p>Additionally, creating a source file that corresponds to an

 * already created class file (or vice versa) also results in an

 * IOException since each type can only be created once.  However, if

 * the Filer is used to create a text file named *.java that happens

 * to correspond to an existing class file, a warning is *not*

 * generated.  Similarly, a warning is not generated for a binary file

 * named *.class and an existing source file.

 *

 * <p>The reason for this difference is that source files and class

 * files are registered with the tool and can get passed on as

 * declarations to the next round of processing.  Files that are just

 * named *.java and *.class are not processed in that manner; although

 * having extra source files and class files on the source path and

 * class path can alter the behavior of the tool and any final

 * compile.

 *

 * <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>

 */

public class JavacFiler implements Filer, Closeable {

    // TODO: Implement different transaction model for updating the

    // Filer's record keeping on file close.

    private static final String ALREADY_OPENED =

        "Output stream or writer has already been opened.";

    private static final String NOT_FOR_READING =

        "FileObject was not opened for reading.";

    private static final String NOT_FOR_WRITING =

        "FileObject was not opened for writing.";

    /**

     * Wrap a JavaFileObject to manage writing by the Filer.

     */

    private class FilerOutputFileObject extends ForwardingFileObject<FileObject> {

        private boolean opened = false;

        private ModuleSymbol mod;

        private String name;

        FilerOutputFileObject(ModuleSymbol mod, String name, FileObject fileObject) {

            super(fileObject);

            this.mod = mod;

            this.name = name;

        }

        @Override @DefinedBy(Api.COMPILER)

        public synchronized OutputStream openOutputStream() throws IOException {

            if (opened)

                throw new IOException(ALREADY_OPENED);

            opened = true;

            return new FilerOutputStream(mod, name, fileObject);

        }

        @Override @DefinedBy(Api.COMPILER)

        public synchronized Writer openWriter() throws IOException {

            if (opened)

                throw new IOException(ALREADY_OPENED);

            opened = true;

            return new FilerWriter(mod, name, fileObject);

        }

        // Three anti-literacy methods

        @Override @DefinedBy(Api.COMPILER)

        public InputStream openInputStream() throws IOException {

            throw new IllegalStateException(NOT_FOR_READING);

        }

        @Override @DefinedBy(Api.COMPILER)

        public Reader openReader(boolean ignoreEncodingErrors) throws IOException {

            throw new IllegalStateException(NOT_FOR_READING);

        }

        @Override @DefinedBy(Api.COMPILER)

        public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {

            throw new IllegalStateException(NOT_FOR_READING);

        }

        @Override @DefinedBy(Api.COMPILER)

        public boolean delete() {

            return false;

        }

    }

    private class FilerOutputJavaFileObject extends FilerOutputFileObject implements JavaFileObject {

        private final JavaFileObject javaFileObject;

        FilerOutputJavaFileObject(ModuleSymbol mod, String name, JavaFileObject javaFileObject) {

            super(mod, name, javaFileObject);

            this.javaFileObject = javaFileObject;

        }

        @DefinedBy(Api.COMPILER)

        public JavaFileObject.Kind getKind() {

            return javaFileObject.getKind();

        }

        @DefinedBy(Api.COMPILER)

        public boolean isNameCompatible(String simpleName,

                                        JavaFileObject.Kind kind) {

            return javaFileObject.isNameCompatible(simpleName, kind);

        }

        @DefinedBy(Api.COMPILER)

        public NestingKind getNestingKind() {

            return javaFileObject.getNestingKind();

        }

        @DefinedBy(Api.COMPILER)

        public Modifier getAccessLevel() {

            return javaFileObject.getAccessLevel();

        }

    }

    /**

     * Wrap a JavaFileObject to manage reading by the Filer.

     */

    private class FilerInputFileObject extends ForwardingFileObject<FileObject> {

        FilerInputFileObject(FileObject fileObject) {

            super(fileObject);

        }

        @Override @DefinedBy(Api.COMPILER)

        public OutputStream openOutputStream() throws IOException {

            throw new IllegalStateException(NOT_FOR_WRITING);

        }

        @Override @DefinedBy(Api.COMPILER)

        public Writer openWriter() throws IOException {

            throw new IllegalStateException(NOT_FOR_WRITING);

        }

        @Override @DefinedBy(Api.COMPILER)

        public boolean delete() {

            return false;

        }

    }

    private class FilerInputJavaFileObject extends FilerInputFileObject implements JavaFileObject {

        private final JavaFileObject javaFileObject;

        FilerInputJavaFileObject(JavaFileObject javaFileObject) {

            super(javaFileObject);

            this.javaFileObject = javaFileObject;

        }

        @DefinedBy(Api.COMPILER)

        public JavaFileObject.Kind getKind() {

            return javaFileObject.getKind();

        }

        @DefinedBy(Api.COMPILER)

        public boolean isNameCompatible(String simpleName,

                                        JavaFileObject.Kind kind) {

            return javaFileObject.isNameCompatible(simpleName, kind);

        }

        @DefinedBy(Api.COMPILER)

        public NestingKind getNestingKind() {

            return javaFileObject.getNestingKind();

        }

        @DefinedBy(Api.COMPILER)

        public Modifier getAccessLevel() {

            return javaFileObject.getAccessLevel();

        }

    }

    /**

     * Wrap a {@code OutputStream} returned from the {@code

     * JavaFileManager} to properly register source or class files

     * when they are closed.

     */

    private class FilerOutputStream extends FilterOutputStream {

        ModuleSymbol mod;

        String typeName;

        FileObject fileObject;

        boolean closed = false;

        /**

         * @param typeName name of class or {@code null} if just a

         * binary file

         */

        FilerOutputStream(ModuleSymbol mod, String typeName, FileObject fileObject) throws IOException {

            super(fileObject.openOutputStream());

            this.mod = mod;

            this.typeName = typeName;

            this.fileObject = fileObject;

        }

        public synchronized void close() throws IOException {

            if (!closed) {

                closed = true;

                /*

                 * If an IOException occurs when closing the underlying

                 * stream, still try to process the file.

                 */

                closeFileObject(mod, typeName, fileObject);

                out.close();

            }

        }

    }

    /**

     * Wrap a {@code Writer} returned from the {@code JavaFileManager}

     * to properly register source or class files when they are

     * closed.

     */

    private class FilerWriter extends FilterWriter {

        ModuleSymbol mod;

        String typeName;

        FileObject fileObject;

        boolean closed = false;

        /**

         * @param fileObject the fileObject to be written to

         * @param typeName name of source file or {@code null} if just a

         * text file

         */

        FilerWriter(ModuleSymbol mod, String typeName, FileObject fileObject) throws IOException {

            super(fileObject.openWriter());

            this.mod = mod;

            this.typeName = typeName;

            this.fileObject = fileObject;

        }

        public synchronized void close() throws IOException {

            if (!closed) {

                closed = true;

                /*

                 * If an IOException occurs when closing the underlying

                 * Writer, still try to process the file.

                 */

                closeFileObject(mod, typeName, fileObject);

                out.close();

            }

        }

    }

    JavaFileManager fileManager;

    JavacElements elementUtils;

    Log log;

    Modules modules;

    Names names;

    Symtab syms;

    Context context;

    boolean lastRound;

    private final boolean lint;

    /**

     * Initial inputs passed to the tool.  This set must be

     * synchronized.

     */

    private final Set<FileObject> initialInputs;

    /**

     * Logical names of all created files.  This set must be

     * synchronized.

     */

    private final Set<FileObject> fileObjectHistory;

    /**

     * Names of types that have had files created but not closed.

     */

    private final Set<String> openTypeNames;

    /**

     * Names of source files closed in this round.  This set must be

     * synchronized.  Its iterators should preserve insertion order.

     */

    private Set<String> generatedSourceNames;

    /**

     * Names and class files of the class files closed in this round.

     * This set must be synchronized.  Its iterators should preserve

     * insertion order.

     */

    private final Map<ModuleSymbol, Map<String, JavaFileObject>> generatedClasses;

    /**

     * JavaFileObjects for source files closed in this round.  This

     * set must be synchronized.  Its iterators should preserve

     * insertion order.

     */

    private Set<JavaFileObject> generatedSourceFileObjects;

    /**

     * Names of all created source files.  Its iterators should

     * preserve insertion order.

     */

    private final Set<Pair<ModuleSymbol, String>> aggregateGeneratedSourceNames;

    /**

     * Names of all created class files.  Its iterators should

     * preserve insertion order.

     */

    private final Set<Pair<ModuleSymbol, String>> aggregateGeneratedClassNames;

    private final Set<String> initialClassNames;

    private final String defaultTargetModule;

    JavacFiler(Context context) {

        this.context = context;

        fileManager = context.get(JavaFileManager.class);

        elementUtils = JavacElements.instance(context);

        log = Log.instance(context);

        modules = Modules.instance(context);

        names = Names.instance(context);

        syms = Symtab.instance(context);

        initialInputs = synchronizedSet(new LinkedHashSet<>());

        fileObjectHistory = synchronizedSet(new LinkedHashSet<>());

        generatedSourceNames = synchronizedSet(new LinkedHashSet<>());

        generatedSourceFileObjects = synchronizedSet(new LinkedHashSet<>());

        generatedClasses = synchronizedMap(new LinkedHashMap<>());

        openTypeNames  = synchronizedSet(new LinkedHashSet<>());

        aggregateGeneratedSourceNames = new LinkedHashSet<>();

        aggregateGeneratedClassNames  = new LinkedHashSet<>();

        initialClassNames  = new LinkedHashSet<>();

        lint = (Lint.instance(context)).isEnabled(PROCESSING);

        Options options = Options.instance(context);

        defaultTargetModule = options.get(Option.DEFAULT_MODULE_FOR_CREATED_FILES);

    }

    @Override @DefinedBy(Api.ANNOTATION_PROCESSING)

    public JavaFileObject createSourceFile(CharSequence nameAndModule,

                                           Element... originatingElements) throws IOException {

        Pair<ModuleSymbol, String> moduleAndClass = checkOrInferModule(nameAndModule);

        return createSourceOrClassFile(moduleAndClass.fst, true, moduleAndClass.snd);

    }

    @Override @DefinedBy(Api.ANNOTATION_PROCESSING)

    public JavaFileObject createClassFile(CharSequence nameAndModule,

                                          Element... originatingElements) throws IOException {

        Pair<ModuleSymbol, String> moduleAndClass = checkOrInferModule(nameAndModule);

        return createSourceOrClassFile(moduleAndClass.fst, false, moduleAndClass.snd);

    }

    private Pair<ModuleSymbol, String> checkOrInferModule(CharSequence moduleAndPkg) throws FilerException {

        String moduleAndPkgString = moduleAndPkg.toString();

        int slash = moduleAndPkgString.indexOf('/');

        String module;

        String pkg;

        if (slash == (-1)) {

            //module name not specified:

            int lastDot = moduleAndPkgString.lastIndexOf('.');

            String pack = lastDot != (-1) ? moduleAndPkgString.substring(0, lastDot) : "";

            ModuleSymbol msym = inferModule(pack);

            if (msym != null) {

                return Pair.of(msym, moduleAndPkgString);

            }

            if (defaultTargetModule == null) {

                throw new FilerException("Cannot determine target module.");

            }

            module = defaultTargetModule;

            pkg = moduleAndPkgString;

        } else {

            //module name specified:

            module = moduleAndPkgString.substring(0, slash);

            pkg = moduleAndPkgString.substring(slash + 1);

        }

        ModuleSymbol explicitModule = syms.getModule(names.fromString(module));

        if (explicitModule == null) {

            throw new FilerException("Module: " + module + " does not exist.");

        }

        if (!modules.isRootModule(explicitModule)) {

            throw new FilerException("Cannot write to the given module.");

        }

        return Pair.of(explicitModule, pkg);

    }

    private JavaFileObject createSourceOrClassFile(ModuleSymbol mod, boolean isSourceFile, String name) throws IOException {

        Assert.checkNonNull(mod);

        if (lint) {

            int periodIndex = name.lastIndexOf(".");

            if (periodIndex != -1) {

                String base = name.substring(periodIndex);

                String extn = (isSourceFile ? ".java" : ".class");

                if (base.equals(extn))

                    log.warning(Warnings.ProcSuspiciousClassName(name, extn));

            }

        }

        checkNameAndExistence(mod, name, isSourceFile);

        Location loc = (isSourceFile ? SOURCE_OUTPUT : CLASS_OUTPUT);

        if (modules.multiModuleMode) {

            loc = this.fileManager.getLocationForModule(loc, mod.name.toString());

        }

        JavaFileObject.Kind kind = (isSourceFile ?

                                    JavaFileObject.Kind.SOURCE :

                                    JavaFileObject.Kind.CLASS);

        JavaFileObject fileObject =

            fileManager.getJavaFileForOutput(loc, name, kind, null);

        checkFileReopening(fileObject, true);

        if (lastRound)

            log.warning(Warnings.ProcFileCreateLastRound(name));

        if (isSourceFile)

            aggregateGeneratedSourceNames.add(Pair.of(mod, name));