/*
 * Copyright (c) 2009, 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
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 * questions.
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package com.sun.tools.javac.file;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CharsetDecoder;
import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.LinkOption;
import java.nio.file.Path;
import java.text.Normalizer;
import java.util.Objects;

import javax.lang.model.element.Modifier;
import javax.lang.model.element.NestingKind;
import javax.tools.FileObject;
import javax.tools.JavaFileObject;

import com.sun.tools.javac.file.RelativePath.RelativeFile;
import com.sun.tools.javac.util.DefinedBy;
import com.sun.tools.javac.util.DefinedBy.Api;


 Implementation of JavaFileObject using java.nio.file API.
 
PathFileObjects are, for the most part, straightforward wrappers around
 immutable absolute Path objects. Different subtypes are used to provide
 specialized implementations of "inferBinaryName" and "getName" that capture
 additional information available at the time the object is created.
 
In general, isSameFile.isSameFile should be used to determine whether two file objects refer to the same file on disk. PathFileObject also supports the standard equals and hashCode methods, primarily for convenience when working with collections. All of these operations delegate to the equivalent operations on the underlying Path object. 
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.
/**
 *  Implementation of JavaFileObject using java.nio.file API.
 *
 *  <p>PathFileObjects are, for the most part, straightforward wrappers around
 *  immutable absolute Path objects. Different subtypes are used to provide
 *  specialized implementations of "inferBinaryName" and "getName" that capture
 *  additional information available at the time the object is created.
 *
 *  <p>In general, {@link JavaFileManager#isSameFile} should be used to
 *  determine whether two file objects refer to the same file on disk.
 *  PathFileObject also supports the standard {@code equals} and {@code hashCode}
 *  methods, primarily for convenience when working with collections.
 *  All of these operations delegate to the equivalent operations on the
 *  underlying Path object.
 *
 *  <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 abstract class PathFileObject implements JavaFileObject {
    private static final FileSystem defaultFileSystem = FileSystems.getDefault();
    private static final boolean isMacOS = System.getProperty("os.name", "").contains("OS X");

    protected final BaseFileManager fileManager;
    protected final Path path;
    private boolean hasParents;

    
Create a PathFileObject for a file within a directory, such that the binary name can be inferred from the relationship to an enclosing directory. The binary name is derived from relativePath. The name is derived from the composition of userPackageRootDir and relativePath. 
Params:
fileManager – the file manager creating this file object
path – the absolute path referred to by this file object
userPackageRootDir – the path of the directory containing the
         root of the package hierarchy
relativePath – the path of this file relative to userPackageRootDir/**
     * Create a PathFileObject for a file within a directory, such that the
     * binary name can be inferred from the relationship to an enclosing directory.
     *
     * The binary name is derived from {@code relativePath}.
     * The name is derived from the composition of {@code userPackageRootDir}
     * and {@code relativePath}.
     *
     * @param fileManager the file manager creating this file object
     * @param path the absolute path referred to by this file object
     * @param userPackageRootDir the path of the directory containing the
     *          root of the package hierarchy
     * @param relativePath the path of this file relative to {@code userPackageRootDir}
     */
    static PathFileObject forDirectoryPath(BaseFileManager fileManager, Path path,
            Path userPackageRootDir, RelativePath relativePath) {
        return new DirectoryFileObject(fileManager, path, userPackageRootDir, relativePath);
    }

    private static class DirectoryFileObject extends PathFileObject {
        private final Path userPackageRootDir;
        private final RelativePath relativePath;

        private DirectoryFileObject(BaseFileManager fileManager, Path path,
                Path userPackageRootDir, RelativePath relativePath) {
            super(fileManager, path);
            this.userPackageRootDir = Objects.requireNonNull(userPackageRootDir);
            this.relativePath = relativePath;
        }

        @Override @DefinedBy(Api.COMPILER)
        public String getName() {
            return relativePath.resolveAgainst(userPackageRootDir).toString();
        }

        @Override
        public String inferBinaryName(Iterable<? extends Path> paths) {
            return toBinaryName(relativePath);
        }

        @Override
        public String toString() {
            return "DirectoryFileObject[" + userPackageRootDir + ":" + relativePath.path + "]";
        }

        @Override
        PathFileObject getSibling(String baseName) {
            return new DirectoryFileObject(fileManager,
                    path.resolveSibling(baseName),
                    userPackageRootDir,
                    new RelativeFile(relativePath.dirname(), baseName)
            );
        }
    }

    
Create a PathFileObject for a file in a file system such as a jar file, such that the binary name can be inferred from its position within the file system. The binary name is derived from path. The name is derived from the composition of userJarPath and path. 
Params:
fileManager – the file manager creating this file object
path – the path referred to by this file object
userJarPath – the path of the jar file containing the file system.
Returns:
the file object/**
     * Create a PathFileObject for a file in a file system such as a jar file,
     * such that the binary name can be inferred from its position within the
     * file system.
     *
     * The binary name is derived from {@code path}.
     * The name is derived from the composition of {@code userJarPath}
     * and {@code path}.
     *
     * @param fileManager the file manager creating this file object
     * @param path the path referred to by this file object
     * @param userJarPath the path of the jar file containing the file system.
     * @return the file object
     */
    public static PathFileObject forJarPath(BaseFileManager fileManager,
            Path path, Path userJarPath) {
        return new JarFileObject(fileManager, path, userJarPath);
    }

    private static class JarFileObject extends PathFileObject {
        private final Path userJarPath;

        private JarFileObject(BaseFileManager fileManager, Path path, Path userJarPath) {
            super(fileManager, path);
            this.userJarPath = userJarPath;
        }

        @Override @DefinedBy(Api.COMPILER)
        public String getName() {
            // The use of ( ) to delimit the entry name is not ideal
            // but it does match earlier behavior
            return userJarPath + "(" + path + ")";
        }

        @Override
        public String inferBinaryName(Iterable<? extends Path> paths) {
            Path root = path.getFileSystem().getRootDirectories().iterator().next();
            return toBinaryName(root.relativize(path));
        }

        @Override @DefinedBy(Api.COMPILER)
        public URI toUri() {
            // Work around bug JDK-8134451:
            // path.toUri() returns double-encoded URIs, that cannot be opened by URLConnection
            return createJarUri(userJarPath, path.toString());
        }

        @Override
        public String toString() {
            return "JarFileObject[" + userJarPath + ":" + path + "]";
        }

        @Override
        PathFileObject getSibling(String baseName) {
            return new JarFileObject(fileManager,
                    path.resolveSibling(baseName),
                    userJarPath
            );
        }

        private static URI createJarUri(Path jarFile, String entryName) {
            URI jarURI = jarFile.toUri().normalize();
            String separator = entryName.startsWith("/") ? "!" : "!/";
            try {
                // The jar URI convention appears to be not to re-encode the jarURI
                return new URI("jar:" + jarURI + separator + entryName);
            } catch (URISyntaxException e) {
                throw new CannotCreateUriError(jarURI + separator + entryName, e);
            }
        }
    }

    
Create a PathFileObject for a file in a modular file system, such as jrt:, such that the binary name can be inferred from its position within the filesystem. The binary name is derived from path, ignoring the first two elements of the name (which are "modules" and a module name). The name is derived from path. 
Params:
fileManager – the file manager creating this file object
path – the path referred to by this file object
Returns:
the file object/**
     * Create a PathFileObject for a file in a modular file system, such as jrt:,
     * such that the binary name can be inferred from its position within the
     * filesystem.
     *
     * The binary name is derived from {@code path}, ignoring the first two
     * elements of the name (which are "modules" and a module name).
     * The name is derived from {@code path}.
     *
     * @param fileManager the file manager creating this file object
     * @param path the path referred to by this file object
     * @return the file object
     */
    public static PathFileObject forJRTPath(BaseFileManager fileManager,
            final Path path) {
        return new JRTFileObject(fileManager, path);
    }

    private static class JRTFileObject extends PathFileObject {
        // private final Path javaHome;
        private JRTFileObject(BaseFileManager fileManager, Path path) {
            super(fileManager, path);
        }

        @Override @DefinedBy(Api.COMPILER)
        public String getName() {
            return path.toString();
        }

        @Override
        public String inferBinaryName(Iterable<? extends Path> paths) {
            // use subpath to ignore the leading /modules/MODULE-NAME
            return toBinaryName(path.subpath(2, path.getNameCount()));
        }

        @Override
        public String toString() {
            return "JRTFileObject[" + path + "]";
        }

        @Override
        PathFileObject getSibling(String baseName) {
            return new JRTFileObject(fileManager,
                    path.resolveSibling(baseName)
            );
        }
    }

    
Create a PathFileObject for a file whose binary name must be inferred from its position on a search path. The binary name is inferred by finding an enclosing directory in the sequence of paths associated with the location given to JavaFileManager#inferBinaryName).
The name is derived from userPath. 
Params:
fileManager – the file manager creating this file object
path – the path referred to by this file object
userPath – the "user-friendly" name for this path./**
     * Create a PathFileObject for a file whose binary name must be inferred
     * from its position on a search path.
     *
     * The binary name is inferred by finding an enclosing directory in
     * the sequence of paths associated with the location given to
     * {@link JavaFileManager#inferBinaryName).
     * The name is derived from {@code userPath}.
     *
     * @param fileManager the file manager creating this file object
     * @param path the path referred to by this file object
     * @param userPath the "user-friendly" name for this path.
     */
    static PathFileObject forSimplePath(BaseFileManager fileManager,
            Path path, Path userPath) {
        return new SimpleFileObject(fileManager, path, userPath);
    }

    private static class SimpleFileObject extends PathFileObject {
        private final Path userPath;
        private SimpleFileObject(BaseFileManager fileManager, Path path, Path userPath) {
            super(fileManager, path);
            this.userPath = userPath;
        }

        @Override @DefinedBy(Api.COMPILER)
        public String getName() {
            return userPath.toString();
        }

        @Override
        public String inferBinaryName(Iterable<? extends Path> paths) {
            Path absPath = path.toAbsolutePath();
            for (Path p: paths) {
                Path ap = p.toAbsolutePath();
                if (absPath.startsWith(ap)) {
                    try {
                        Path rp = ap.relativize(absPath);
                        if (rp != null) // maybe null if absPath same as ap
                            return toBinaryName(rp);
                    } catch (IllegalArgumentException e) {
                        // ignore this p if cannot relativize path to p
                    }
                }
            }
            return null;
        }

        @Override @DefinedBy(Api.COMPILER)
        public Kind getKind() {
            return BaseFileManager.getKind(userPath);
        }

        @Override @DefinedBy(Api.COMPILER)
        public boolean isNameCompatible(String simpleName, Kind kind) {
            return isPathNameCompatible(userPath, simpleName, kind);
        }

        @Override
        PathFileObject getSibling(String baseName) {
            return new SimpleFileObject(fileManager,
                    path.resolveSibling(baseName),
                    userPath.resolveSibling(baseName)
            );
        }
    }

    
Create a PathFileObject, for a specified path, in the context of a given file manager. In general, this path should be an absolute path, if not a Path.toRealPath real path. It will be used as the basis of equals, hashCode and isSameFile methods on this file object. A PathFileObject should also have a "friendly name" per the specification for FileObject.getName. The friendly name is provided by the various subtypes of PathFileObject. 
Params:
fileManager – the file manager creating this file object
path – the path contained in this file object./**
     * Create a PathFileObject, for a specified path, in the context of
     * a given file manager.
     *
     * In general, this path should be an
     * {@link Path#toAbsolutePath absolute path}, if not a
     * {@link Path#toRealPath} real path.
     * It will be used as the basis of {@code equals}, {@code hashCode}
     * and {@code isSameFile} methods on this file object.
     *
     * A PathFileObject should also have a "friendly name" per the
     * specification for {@link FileObject#getName}. The friendly name
     * is provided by the various subtypes of {@code PathFileObject}.
     *
     * @param fileManager the file manager creating this file object
     * @param path the path contained in this file object.
     */
    protected PathFileObject(BaseFileManager fileManager, Path path) {
        this.fileManager = Objects.requireNonNull(fileManager);
        if (Files.isDirectory(path)) {
            throw new IllegalArgumentException("directories not supported");
        }
        this.path = path;
    }

    
See JavacFileManager.inferBinaryName. /**
     * See {@link JavacFileManager#inferBinaryName}.
     */
    abstract String inferBinaryName(Iterable<? extends Path> paths);

    
Return the file object for a sibling file with a given file name. See JavacFileManager.getFileForOutput and JavacFileManager.getJavaFileForOutput. /**
     * Return the file object for a sibling file with a given file name.
     * See {@link JavacFileManager#getFileForOutput} and
     * {@link JavacFileManager#getJavaFileForOutput}.
     */
    abstract PathFileObject getSibling(String basename);

    
Return the Path for this object.
See Also:
asPath.asPath
Returns:
the Path for this object./**
     * Return the Path for this object.
     * @return the Path for this object.
     * @see StandardJavaFileManager#asPath
     */
    public Path getPath() {
        return path;
    }

    
The short name is used when generating raw diagnostics.
Returns:
the last component of the path/**
     * The short name is used when generating raw diagnostics.
     * @return the last component of the path
     */
    public String getShortName() {
        return path.getFileName().toString();
    }

    @Override @DefinedBy(Api.COMPILER)
    public Kind getKind() {
        return BaseFileManager.getKind(path);
    }

    @Override @DefinedBy(Api.COMPILER)
    public boolean isNameCompatible(String simpleName, Kind kind) {
        return isPathNameCompatible(path, simpleName, kind);
    }

    protected boolean isPathNameCompatible(Path p, String simpleName, Kind kind) {
        Objects.requireNonNull(simpleName);
        Objects.requireNonNull(kind);

        if (kind == Kind.OTHER && BaseFileManager.getKind(p) != kind) {
            return false;
        }

        String sn = simpleName + kind.extension;
        String pn = p.getFileName().toString();
        if (pn.equals(sn)) {
            return true;
        }

        if (p.getFileSystem() == defaultFileSystem) {
            if (isMacOS) {
                if (Normalizer.isNormalized(pn, Normalizer.Form.NFD)
                        && Normalizer.isNormalized(sn, Normalizer.Form.NFC)) {
                    // On Mac OS X it is quite possible to have the file name and the
                    // given simple name normalized in different ways.
                    // In that case we have to normalize file name to the
                    // Normal Form Composed (NFC).
                    String normName = Normalizer.normalize(pn, Normalizer.Form.NFC);
                    if (normName.equals(sn)) {
                        return true;
                    }
                }
            }

            if (pn.equalsIgnoreCase(sn)) {
                try {
                    // allow for Windows
                    return p.toRealPath(LinkOption.NOFOLLOW_LINKS).getFileName().toString().equals(sn);
                } catch (IOException e) {
                }
            }
        }

        return false;
    }

    @Override @DefinedBy(Api.COMPILER)
    public NestingKind getNestingKind() {
        return null;
    }

    @Override @DefinedBy(Api.COMPILER)
    public Modifier getAccessLevel() {
        return null;
    }

    @Override @DefinedBy(Api.COMPILER)
    public URI toUri() {
        return path.toUri();
    }

    @Override @DefinedBy(Api.COMPILER)
    public InputStream openInputStream() throws IOException {
        fileManager.updateLastUsedTime();
        return Files.newInputStream(path);
    }

    @Override @DefinedBy(Api.COMPILER)
    public OutputStream openOutputStream() throws IOException {
        fileManager.updateLastUsedTime();
        fileManager.flushCache(this);
        ensureParentDirectoriesExist();
        return Files.newOutputStream(path);
    }

    @Override @DefinedBy(Api.COMPILER)
    public Reader openReader(boolean ignoreEncodingErrors) throws IOException {
        CharsetDecoder decoder = fileManager.getDecoder(fileManager.getEncodingName(), ignoreEncodingErrors);
        return new InputStreamReader(openInputStream(), decoder);
    }

    @Override @DefinedBy(Api.COMPILER)
    public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {
        CharBuffer cb = fileManager.getCachedContent(this);
        if (cb == null) {
            try (InputStream in = openInputStream()) {
                ByteBuffer bb = fileManager.makeByteBuffer(in);
                JavaFileObject prev = fileManager.log.useSource(this);
                try {
                    cb = fileManager.decode(bb, ignoreEncodingErrors);
                } finally {
                    fileManager.log.useSource(prev);
                }
                fileManager.recycleByteBuffer(bb);
                if (!ignoreEncodingErrors) {
                    fileManager.cache(this, cb);
                }
            }
        }
        return cb;
    }

    @Override @DefinedBy(Api.COMPILER)
    public Writer openWriter() throws IOException {
        fileManager.updateLastUsedTime();
        fileManager.flushCache(this);
        ensureParentDirectoriesExist();
        return new OutputStreamWriter(Files.newOutputStream(path), fileManager.getEncodingName());
    }

    @Override @DefinedBy(Api.COMPILER)
    public long getLastModified() {
        try {
            return Files.getLastModifiedTime(path).toMillis();
        } catch (IOException e) {
            return 0;
        }
    }

    @Override @DefinedBy(Api.COMPILER)
    public boolean delete() {
        try {
            Files.delete(path);
            return true;
        } catch (IOException e) {
            return false;
        }
    }

    boolean isSameFile(PathFileObject other) {
        // By construction, the "path" field should be canonical in all likely, supported scenarios.
        // (Any exceptions would involve the use of symlinks within a package hierarchy.)
        // Therefore, it is sufficient to check that the paths are .equals.
        return path.equals(other.path);
    }

    @Override
    public boolean equals(Object other) {
        return (other instanceof PathFileObject && path.equals(((PathFileObject) other).path));
    }

    @Override
    public int hashCode() {
        return path.hashCode();
    }

    @Override
    public String toString() {
        return getClass().getSimpleName() + "[" + path + "]";
    }

    private void ensureParentDirectoriesExist() throws IOException {
        if (!hasParents) {
            Path parent = path.getParent();
            if (parent != null && !Files.isDirectory(parent)) {
                try {
                    Files.createDirectories(parent);
                } catch (IOException e) {
                    throw new IOException("could not create parent directories", e);
                }
            }
            hasParents = true;
        }
    }

    protected static String toBinaryName(RelativePath relativePath) {
        return toBinaryName(relativePath.path, "/");
    }

    protected static String toBinaryName(Path relativePath) {
        return toBinaryName(relativePath.toString(),
                relativePath.getFileSystem().getSeparator());
    }

    private static String toBinaryName(String relativePath, String sep) {
        return removeExtension(relativePath).replace(sep, ".");
    }

    private static String removeExtension(String fileName) {
        int lastDot = fileName.lastIndexOf(".");
        return (lastDot == -1 ? fileName : fileName.substring(0, lastDot));
    }

    
Return the last component of a presumed hierarchical URI.
From the scheme specific part of the URI, it returns the substring
after the last "/" if any, or everything if no "/" is found.
Params:
fo – the file object
Returns:
the simple name of the file object/**
     * Return the last component of a presumed hierarchical URI.
     * From the scheme specific part of the URI, it returns the substring
     * after the last "/" if any, or everything if no "/" is found.
     * @param fo the file object
     * @return the simple name of the file object
     */
    public static String getSimpleName(FileObject fo) {
        URI uri = fo.toUri();
        String s = uri.getSchemeSpecificPart();
        return s.substring(s.lastIndexOf("/") + 1); // safe when / not found

    }

    
Used when URLSyntaxException is thrown unexpectedly during
 implementations of FileObject.toURI(). /** Used when URLSyntaxException is thrown unexpectedly during
     *  implementations of FileObject.toURI(). */
    public static class CannotCreateUriError extends Error {
        private static final long serialVersionUID = 9101708840997613546L;
        public CannotCreateUriError(String value, Throwable cause) {
            super(value, cause);
        }
    }
}