/*

 * Copyright (c) 2005, 2014, 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.util.*;

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

/**

 * 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 String name;

        FilerOutputFileObject(String name, FileObject fileObject) {

            super(fileObject);

            this.name = name;

        }

        @Override

        public synchronized OutputStream openOutputStream() throws IOException {

            if (opened)

                throw new IOException(ALREADY_OPENED);

            opened = true;

            return new FilerOutputStream(name, fileObject);

        }

        @Override

        public synchronized Writer openWriter() throws IOException {

            if (opened)

                throw new IOException(ALREADY_OPENED);

            opened = true;

            return new FilerWriter(name, fileObject);

        }

        // Three anti-literacy methods

        @Override

        public InputStream openInputStream() throws IOException {

            throw new IllegalStateException(NOT_FOR_READING);

        }

        @Override

        public Reader openReader(boolean ignoreEncodingErrors) throws IOException {

            throw new IllegalStateException(NOT_FOR_READING);

        }

        @Override

        public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {

            throw new IllegalStateException(NOT_FOR_READING);

        }

        @Override

        public boolean delete() {

            return false;

        }

    }

    private class FilerOutputJavaFileObject extends FilerOutputFileObject implements JavaFileObject {

        private final JavaFileObject javaFileObject;

        FilerOutputJavaFileObject(String name, JavaFileObject javaFileObject) {

            super(name, javaFileObject);

            this.javaFileObject = javaFileObject;

        }

        public JavaFileObject.Kind getKind() {

            return javaFileObject.getKind();

        }

        public boolean isNameCompatible(String simpleName,

                                        JavaFileObject.Kind kind) {

            return javaFileObject.isNameCompatible(simpleName, kind);

        }

        public NestingKind getNestingKind() {

            return javaFileObject.getNestingKind();

        }

        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

        public OutputStream openOutputStream() throws IOException {

            throw new IllegalStateException(NOT_FOR_WRITING);

        }

        @Override

        public Writer openWriter() throws IOException {

            throw new IllegalStateException(NOT_FOR_WRITING);

        }

        @Override

        public boolean delete() {

            return false;

        }

    }

    private class FilerInputJavaFileObject extends FilerInputFileObject implements JavaFileObject {

        private final JavaFileObject javaFileObject;

        FilerInputJavaFileObject(JavaFileObject javaFileObject) {

            super(javaFileObject);

            this.javaFileObject = javaFileObject;

        }

        public JavaFileObject.Kind getKind() {

            return javaFileObject.getKind();

        }

        public boolean isNameCompatible(String simpleName,

                                        JavaFileObject.Kind kind) {

            return javaFileObject.isNameCompatible(simpleName, kind);

        }

        public NestingKind getNestingKind() {

            return javaFileObject.getNestingKind();

        }

        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 {

        String typeName;

        FileObject fileObject;

        boolean closed = false;

        /**

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

         * binary file

         */

        FilerOutputStream(String typeName, FileObject fileObject) throws IOException {

            super(fileObject.openOutputStream());

            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(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 {

        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(String typeName, FileObject fileObject) throws IOException {

            super(fileObject.openWriter());

            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(typeName, fileObject);

                out.close();

            }

        }

    }

    JavaFileManager fileManager;

    Log log;

    Context context;

    boolean lastRound;

    private final boolean lint;

    /**

     * 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<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<String> aggregateGeneratedSourceNames;

    /**

     * Names of all created class files.  Its iterators should

     * preserve insertion order.

     */

    private final Set<String> aggregateGeneratedClassNames;

    JavacFiler(Context context) {

        this.context = context;

        fileManager = context.get(JavaFileManager.class);

        log = Log.instance(context);

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

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

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

        generatedClasses = synchronizedMap(new LinkedHashMap<String, JavaFileObject>());

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

        aggregateGeneratedSourceNames = new LinkedHashSet<>();

        aggregateGeneratedClassNames  = new LinkedHashSet<>();

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

    }

    public JavaFileObject createSourceFile(CharSequence name,

                                           Element... originatingElements) throws IOException {

        return createSourceOrClassFile(true, name.toString());

    }

    public JavaFileObject createClassFile(CharSequence name,

                                           Element... originatingElements) throws IOException {

        return createSourceOrClassFile(false, name.toString());

    }

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

        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("proc.suspicious.class.name", name, extn);

            }

        }

        checkNameAndExistence(name, isSourceFile);

        Location loc = (isSourceFile ? SOURCE_OUTPUT : CLASS_OUTPUT);

        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("proc.file.create.last.round", name);

        if (isSourceFile)

            aggregateGeneratedSourceNames.add(name);

        else

            aggregateGeneratedClassNames.add(name);

        openTypeNames.add(name);

        return new FilerOutputJavaFileObject(name, fileObject);

    }

    public FileObject createResource(JavaFileManager.Location location,

                                     CharSequence pkg,

                                     CharSequence relativeName,

                                     Element... originatingElements) throws IOException {

        locationCheck(location);

        String strPkg = pkg.toString();

        if (strPkg.length() > 0)

            checkName(strPkg);

        FileObject fileObject =

            fileManager.getFileForOutput(location, strPkg,

                                         relativeName.toString(), null);

        checkFileReopening(fileObject, true);

        if (fileObject instanceof JavaFileObject)

            return new FilerOutputJavaFileObject(null, (JavaFileObject)fileObject);

        else

            return new FilerOutputFileObject(null, fileObject);

    }

    private void locationCheck(JavaFileManager.Location location) {

        if (location instanceof StandardLocation) {

            StandardLocation stdLoc = (StandardLocation) location;

            if (!stdLoc.isOutputLocation())

                throw new IllegalArgumentException("Resource creation not supported in location " +

                                                   stdLoc);

        }

    }

    public FileObject getResource(JavaFileManager.Location location,

                                  CharSequence pkg,

                                  CharSequence relativeName) throws IOException {

        String strPkg = pkg.toString();

        if (strPkg.length() > 0)

            checkName(strPkg);

        // TODO: Only support reading resources in selected output

        // locations?  Only allow reading of non-source, non-class

        // files from the supported input locations?

        // In the following, getFileForInput is the "obvious" method

        // to use, but it does not have the "obvious" semantics for

        // SOURCE_OUTPUT and CLASS_OUTPUT. Conversely, getFileForOutput

        // does not have the correct semantics for any "path" location

        // with more than one component. So, for now, we use a hybrid

        // invocation.

        FileObject fileObject;

        if (location.isOutputLocation()) {

            fileObject = fileManager.getFileForOutput(location,

                    pkg.toString(),

                    relativeName.toString(),

                    null);

        } else {

            fileObject = fileManager.getFileForInput(location,

                    pkg.toString(),

                    relativeName.toString());

        }

        if (fileObject == null) {

            String name = (pkg.length() == 0)

                    ? relativeName.toString() : (pkg + "/" + relativeName);

            throw new FileNotFoundException(name);

        }

        // If the path was already opened for writing, throw an exception.

        checkFileReopening(fileObject, false);

        return new FilerInputFileObject(fileObject);

    }

    private void checkName(String name) throws FilerException {

        checkName(name, false);

    }

    private void checkName(String name, boolean allowUnnamedPackageInfo) throws FilerException {

        if (!SourceVersion.isName(name) && !isPackageInfo(name, allowUnnamedPackageInfo)) {

            if (lint)

                log.warning("proc.illegal.file.name", name);

            throw new FilerException("Illegal name " + name);

        }

    }

    private boolean isPackageInfo(String name, boolean allowUnnamedPackageInfo) {

        // Is the name of the form "package-info" or

        // "foo.bar.package-info"?

        final String PKG_INFO = "package-info";

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

        if (periodIndex == -1) {

            return allowUnnamedPackageInfo ? name.equals(PKG_INFO) : false;

        } else {

            // "foo.bar.package-info." illegal

            String prefix = name.substring(0, periodIndex);

            String simple = name.substring(periodIndex+1);

            return SourceVersion.isName(prefix) && simple.equals(PKG_INFO);

        }

    }

    private void checkNameAndExistence(String typename, boolean allowUnnamedPackageInfo) throws FilerException {

        // TODO: Check if type already exists on source or class path?

        // If so, use warning message key proc.type.already.exists

        checkName(typename, allowUnnamedPackageInfo);

        if (aggregateGeneratedSourceNames.contains(typename) ||

            aggregateGeneratedClassNames.contains(typename)) {

            if (lint)

                log.warning("proc.type.recreate", typename);

            throw new FilerException("Attempt to recreate a file for type " + typename);