/*
 * Copyright (c) 1997, 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 java.io;

import java.nio.file.*;
import java.security.*;
import java.util.Enumeration;
import java.util.Objects;
import java.util.StringJoiner;
import java.util.Vector;
import java.util.concurrent.ConcurrentHashMap;

import jdk.internal.access.JavaIOFilePermissionAccess;
import jdk.internal.access.SharedSecrets;
import sun.nio.fs.DefaultFileSystemProvider;
import sun.security.action.GetPropertyAction;
import sun.security.util.FilePermCompat;
import sun.security.util.SecurityConstants;

/**
 * This class represents access to a file or directory. A FilePermission consists
 * of a pathname and a set of actions valid for that pathname.
 * <P>
 * Pathname is the pathname of the file or directory granted the specified
 * actions. A pathname that ends in "/*" (where "/" is
 * the file separator character, <code>File.separatorChar</code>) indicates
 * all the files and directories contained in that directory. A pathname
 * that ends with "/-" indicates (recursively) all files
 * and subdirectories contained in that directory. Such a pathname is called
 * a wildcard pathname. Otherwise, it's a simple pathname.
 * <P>
 * A pathname consisting of the special token {@literal "<<ALL FILES>>"}
 * matches <b>any</b> file.
 * <P>
 * Note: A pathname consisting of a single "*" indicates all the files
 * in the current directory, while a pathname consisting of a single "-"
 * indicates all the files in the current directory and
 * (recursively) all files and subdirectories contained in the current
 * directory.
 * <P>
 * The actions to be granted are passed to the constructor in a string containing
 * a list of one or more comma-separated keywords. The possible keywords are
 * "read", "write", "execute", "delete", and "readlink". Their meaning is
 * defined as follows:
 *
 * <DL>
 * <DT> read <DD> read permission
 * <DT> write <DD> write permission
 * <DT> execute
 * <DD> execute permission. Allows <code>Runtime.exec</code> to
 * be called. Corresponds to <code>SecurityManager.checkExec</code>.
 * <DT> delete
 * <DD> delete permission. Allows <code>File.delete</code> to
 * be called. Corresponds to <code>SecurityManager.checkDelete</code>.
 * <DT> readlink
 * <DD> read link permission. Allows the target of a
 * <a href="../nio/file/package-summary.html#links">symbolic link</a>
 * to be read by invoking the {@link java.nio.file.Files#readSymbolicLink
 * readSymbolicLink } method.
 * </DL>
 * <P>
 * The actions string is converted to lowercase before processing.
 * <P>
 * Be careful when granting FilePermissions. Think about the implications
 * of granting read and especially write access to various files and
 * directories. The {@literal "<<ALL FILES>>"} permission with write action is
 * especially dangerous. This grants permission to write to the entire
 * file system. One thing this effectively allows is replacement of the
 * system binary, including the JVM runtime environment.
 * <P>
 * Please note: Code can always read a file from the same
 * directory it's in (or a subdirectory of that directory); it does not
 * need explicit permission to do so.
 *
 * @see java.security.Permission
 * @see java.security.Permissions
 * @see java.security.PermissionCollection
 *
 *
 * @author Marianne Mueller
 * @author Roland Schemers
 * @since 1.2
 *
 * @serial exclude
 */

public final class FilePermission extends Permission implements Serializable {

 /**
 * Execute action.
 */
 private static final int EXECUTE = 0x1;
 /**
 * Write action.
 */
 private static final int WRITE = 0x2;
 /**
 * Read action.
 */
 private static final int READ = 0x4;
 /**
 * Delete action.
 */
 private static final int DELETE = 0x8;
 /**
 * Read link action.
 */
 private static final int READLINK = 0x10;

 /**
 * All actions (read,write,execute,delete,readlink)
 */
 private static final int ALL = READ|WRITE|EXECUTE|DELETE|READLINK;
 /**
 * No actions.
 */
 private static final int NONE = 0x0;

 // the actions mask
 private transient int mask;

 // does path indicate a directory? (wildcard or recursive)
 private transient boolean directory;

 // is it a recursive directory specification?
 private transient boolean recursive;

 /**
 * the actions string.
 *
 * @serial
 */
 private String actions; // Left null as long as possible, then
 // created and re-used in the getAction function.

 // canonicalized dir path. used by the "old" behavior (nb == false).
 // In the case of directories, it is the name "/blah/*" or "/blah/-"
 // without the last character (the "*" or "-").

 private transient String cpath;

 // Following fields used by the "new" behavior (nb == true), in which
 // input path is not canonicalized. For compatibility (so that granting
 // FilePermission on "x" allows reading "`pwd`/x", an alternative path
 // can be added so that both can be used in an implies() check. Please note
 // the alternative path only deals with absolute/relative path, and does
 // not deal with symlink/target.

 private transient Path npath; // normalized dir path.
 private transient Path npath2; // alternative normalized dir path.
 private transient boolean allFiles; // whether this is <<ALL FILES>>
 private transient boolean invalid; // whether input path is invalid

 // static Strings used by init(int mask)
 private static final char RECURSIVE_CHAR = '-';
 private static final char WILD_CHAR = '*';

// public String toString() {
// StringBuffer sb = new StringBuffer();
// sb.append("*** FilePermission on " + getName() + " ***");
// for (Field f : FilePermission.class.getDeclaredFields()) {
// if (!Modifier.isStatic(f.getModifiers())) {
// try {
// sb.append(f.getName() + " = " + f.get(this));
// } catch (Exception e) {
// sb.append(f.getName() + " = " + e.toString());
// }
// sb.append('\n');
// }
// }
// sb.append("***\n");
// return sb.toString();
// }

 private static final long serialVersionUID = 7930732926638008763L;

 /**
 * Use the platform's default file system to avoid recursive initialization
 * issues when the VM is configured to use a custom file system provider.
 */
 private static final java.nio.file.FileSystem builtInFS =
 DefaultFileSystemProvider.theFileSystem();

 private static final Path here = builtInFS.getPath(
 GetPropertyAction.privilegedGetProperty("user.dir"));

 private static final Path EMPTY_PATH = builtInFS.getPath("");
 private static final Path DASH_PATH = builtInFS.getPath("-");
 private static final Path DOTDOT_PATH = builtInFS.getPath("..");

 /**
 * A private constructor that clones some and updates some,
 * always with a different name.
 * @param input
 */
 private FilePermission(String name,
 FilePermission input,
 Path npath,
 Path npath2,
 int mask,
 String actions) {
 super(name);
 // Customizables
 this.npath = npath;
 this.npath2 = npath2;
 this.actions = actions;
 this.mask = mask;
 // Cloneds
 this.allFiles = input.allFiles;
 this.invalid = input.invalid;
 this.recursive = input.recursive;
 this.directory = input.directory;
 this.cpath = input.cpath;
 }

 /**
 * Returns the alternative path as a Path object, i.e. absolute path
 * for a relative one, or vice versa.
 *
 * @param in a real path w/o "-" or "*" at the end, and not <<ALL FILES>>.
 * @return the alternative path, or null if cannot find one.
 */
 private static Path altPath(Path in) {
 try {
 if (!in.isAbsolute()) {
 return here.resolve(in).normalize();
 } else {
 return here.relativize(in).normalize();
 }
 } catch (IllegalArgumentException e) {
 return null;
 }
 }

 static {
 SharedSecrets.setJavaIOFilePermissionAccess(
 /**
 * Creates FilePermission objects with special internals.
 * See {@link FilePermCompat#newPermPlusAltPath(Permission)} and
 * {@link FilePermCompat#newPermUsingAltPath(Permission)}.
 */
 new JavaIOFilePermissionAccess() {
 public FilePermission newPermPlusAltPath(FilePermission input) {
 if (!input.invalid && input.npath2 == null && !input.allFiles) {
 Path npath2 = altPath(input.npath);
 if (npath2 != null) {
 // Please note the name of the new permission is
 // different than the original so that when one is
 // added to a FilePermissionCollection it will not
 // be merged with the original one.
 return new FilePermission(input.getName() + "#plus",
 input,
 input.npath,
 npath2,
 input.mask,
 input.actions);
 }
 }
 return input;
 }
 public FilePermission newPermUsingAltPath(FilePermission input) {
 if (!input.invalid && !input.allFiles) {
 Path npath2 = altPath(input.npath);
 if (npath2 != null) {
 // New name, see above.
 return new FilePermission(input.getName() + "#using",
 input,
 npath2,
 null,
 input.mask,
 input.actions);
 }
 }
 return null;
 }
 }
 );
 }

 /**
 * initialize a FilePermission object. Common to all constructors.
 * Also called during de-serialization.
 *
 * @param mask the actions mask to use.
 *
 */
 private void init(int mask) {
 if ((mask & ALL) != mask)
 throw new IllegalArgumentException("invalid actions mask");

 if (mask == NONE)
 throw new IllegalArgumentException("invalid actions mask");

 if (FilePermCompat.nb) {
 String name = getName();

 if (name == null)
 throw new NullPointerException("name can't be null");

 this.mask = mask;

 if (name.equals("<<ALL FILES>>")) {
 allFiles = true;
 npath = EMPTY_PATH;
 // other fields remain default
 return;
 }

 boolean rememberStar = false;
 if (name.endsWith("*")) {
 rememberStar = true;
 recursive = false;
 name = name.substring(0, name.length()-1) + "-";
 }

 try {
 // new File() can "normalize" some name, for example, "/C:/X" on
 // Windows. Some JDK codes generate such illegal names.
 npath = builtInFS.getPath(new File(name).getPath())
 .normalize();
 // lastName should always be non-null now
 Path lastName = npath.getFileName();
 if (lastName != null && lastName.equals(DASH_PATH)) {
 directory = true;
 recursive = !rememberStar;
 npath = npath.getParent();
 }
 if (npath == null) {
 npath = EMPTY_PATH;
 }
 invalid = false;
 } catch (InvalidPathException ipe) {
 // Still invalid. For compatibility reason, accept it
 // but make this permission useless.
 npath = builtInFS.getPath("-u-s-e-l-e-s-s-");
 invalid = true;
 }

 } else {
 if ((cpath = getName()) == null)
 throw new NullPointerException("name can't be null");

 this.mask = mask;

 if (cpath.equals("<<ALL FILES>>")) {
 directory = true;
 recursive = true;
 cpath = "";
 return;
 }

 // store only the canonical cpath if possible
 cpath = AccessController.doPrivileged(new PrivilegedAction<>() {
 public String run() {
 try {
 String path = cpath;
 if (cpath.endsWith("*")) {
 // call getCanonicalPath with a path with wildcard character
 // replaced to avoid calling it with paths that are
 // intended to match all entries in a directory
 path = path.substring(0, path.length() - 1) + "-";
 path = new File(path).getCanonicalPath();
 return path.substring(0, path.length() - 1) + "*";
 } else {
 return new File(path).getCanonicalPath();
 }
 } catch (IOException ioe) {
 return cpath;
 }
 }
 });

 int len = cpath.length();
 char last = ((len > 0) ? cpath.charAt(len - 1) : 0);

 if (last == RECURSIVE_CHAR &&
 cpath.charAt(len - 2) == File.separatorChar) {
 directory = true;
 recursive = true;
 cpath = cpath.substring(0, --len);
 } else if (last == WILD_CHAR &&
 cpath.charAt(len - 2) == File.separatorChar) {
 directory = true;
 //recursive = false;
 cpath = cpath.substring(0, --len);
 } else {
 // overkill since they are initialized to false, but
 // commented out here to remind us...
 //directory = false;
 //recursive = false;
 }

 // XXX: at this point the path should be absolute. die if it isn't?
 }
 }

 /**
 * Creates a new FilePermission object with the specified actions.
 * <i>path</i> is the pathname of a file or directory, and <i>actions</i>
 * contains a comma-separated list of the desired actions granted on the
 * file or directory. Possible actions are
 * "read", "write", "execute", "delete", and "readlink".
 *
 * <p>A pathname that ends in "/*" (where "/" is
 * the file separator character, <code>File.separatorChar</code>)
 * indicates all the files and directories contained in that directory.
 * A pathname that ends with "/-" indicates (recursively) all files and
 * subdirectories contained in that directory. The special pathname
 * {@literal "<<ALL FILES>>"} matches any file.
 *
 * <p>A pathname consisting of a single "*" indicates all the files
 * in the current directory, while a pathname consisting of a single "-"
 * indicates all the files in the current directory and
 * (recursively) all files and subdirectories contained in the current
 * directory.
 *
 * <p>A pathname containing an empty string represents an empty path.
 *
 * @implNote In this implementation, the
 * {@code jdk.io.permissionsUseCanonicalPath} system property dictates how
 * the {@code path} argument is processed and stored.
 * <P>
 * If the value of the system property is set to {@code true}, {@code path}
 * is canonicalized and stored as a String object named {@code cpath}.
 * This means a relative path is converted to an absolute path, a Windows
 * DOS-style 8.3 path is expanded to a long path, and a symbolic link is
 * resolved to its target, etc.
 * <P>
 * If the value of the system property is set to {@code false}, {@code path}
 * is converted to a {@link java.nio.file.Path} object named {@code npath}
 * after {@link Path#normalize() normalization}. No canonicalization is
 * performed which means the underlying file system is not accessed.
 * If an {@link InvalidPathException} is thrown during the conversion,
 * this {@code FilePermission} will be labeled as invalid.
 * <P>
 * In either case, the "*" or "-" character at the end of a wildcard
 * {@code path} is removed before canonicalization or normalization.
 * It is stored in a separate wildcard flag field.
 * <P>
 * The default value of the {@code jdk.io.permissionsUseCanonicalPath}
 * system property is {@code false} in this implementation.
 *
 * @param path the pathname of the file/directory.
 * @param actions the action string.
 *
 * @throws IllegalArgumentException
 * If actions is <code>null</code>, empty or contains an action
 * other than the specified possible actions.
 */
 public FilePermission(String path, String actions) {
 super(path);
 init(getMask(actions));
 }

 /**
 * Creates a new FilePermission object using an action mask.
 * More efficient than the FilePermission(String, String) constructor.
 * Can be used from within
 * code that needs to create a FilePermission object to pass into the
 * <code>implies</code> method.
 *
 * @param path the pathname of the file/directory.
 * @param mask the action mask to use.
 */
 // package private for use by the FilePermissionCollection add method
 FilePermission(String path, int mask) {
 super(path);
 init(mask);
 }

 /**
 * Checks if this FilePermission object "implies" the specified permission.
 * <P>
 * More specifically, this method returns true if:
 * <ul>
 * <li> <i>p</i> is an instanceof FilePermission,
 * <li> <i>p</i>'s actions are a proper subset of this
 * object's actions, and
 * <li> <i>p</i>'s pathname is implied by this object's
 * pathname. For example, "/tmp/*" implies "/tmp/foo", since
 * "/tmp/*" encompasses all files in the "/tmp" directory,
 * including the one named "foo".
 * </ul>
 * <P>
 * Precisely, a simple pathname implies another simple pathname
 * if and only if they are equal. A simple pathname never implies
 * a wildcard pathname. A wildcard pathname implies another wildcard
 * pathname if and only if all simple pathnames implied by the latter
 * are implied by the former. A wildcard pathname implies a simple
 * pathname if and only if
 * <ul>
 * <li>if the wildcard flag is "*", the simple pathname's path
 * must be right inside the wildcard pathname's path.
 * <li>if the wildcard flag is "-", the simple pathname's path
 * must be recursively inside the wildcard pathname's path.
 * </ul>
 * <P>
 * {@literal "<<ALL FILES>>"} implies every other pathname. No pathname,
 * except for {@literal "<<ALL FILES>>"} itself, implies
 * {@literal "<<ALL FILES>>"}.
 *
 * @implNote
 * If {@code jdk.io.permissionsUseCanonicalPath} is {@code true}, a
 * simple {@code cpath} is inside a wildcard {@code cpath} if and only if
 * after removing the base name (the last name in the pathname's name
 * sequence) from the former the remaining part equals to the latter,
 * a simple {@code cpath} is recursively inside a wildcard {@code cpath}
 * if and only if the former starts with the latter.
 * <p>
 * If {@code jdk.io.permissionsUseCanonicalPath} is {@code false}, a
 * simple {@code npath} is inside a wildcard {@code npath} if and only if
 * {@code simple_npath.relativize(wildcard_npath)} is exactly "..",
 * a simple {@code npath} is recursively inside a wildcard {@code npath}
 * if and only if {@code simple_npath.relativize(wildcard_npath)} is a
 * series of one or more "..". This means "/-" implies "/foo" but not "foo".
 * <p>
 * An invalid {@code FilePermission} does not imply any object except for
 * itself. An invalid {@code FilePermission} is not implied by any object
 * except for itself or a {@code FilePermission} on
 * {@literal "<<ALL FILES>>"} whose actions is a superset of this
 * invalid {@code FilePermission}. Even if two {@code FilePermission}
 * are created with the same invalid path, one does not imply the other.
 *
 * @param p the permission to check against.
 *
 * @return <code>true</code> if the specified permission is not
 * <code>null</code> and is implied by this object,
 * <code>false</code> otherwise.
 */
 @Override
 public boolean implies(Permission p) {
 if (!(p instanceof FilePermission))
 return false;

 FilePermission that = (FilePermission) p;

 // we get the effective mask. i.e., the "and" of this and that.
 // They must be equal to that.mask for implies to return true.

 return ((this.mask & that.mask) == that.mask) && impliesIgnoreMask(that);
 }

 /**
 * Checks if the Permission's actions are a proper subset of the
 * this object's actions. Returns the effective mask iff the
 * this FilePermission's path also implies that FilePermission's path.
 *
 * @param that the FilePermission to check against.
 * @return the effective mask
 */
 boolean impliesIgnoreMask(FilePermission that) {
 if (FilePermCompat.nb) {
 if (this == that) {
 return true;
 }
 if (allFiles) {
 return true;
 }
 if (this.invalid || that.invalid) {
 return false;
 }
 if (that.allFiles) {
 return false;
 }
 // Left at least same level of wildness as right
 if ((this.recursive && that.recursive) != that.recursive
 || (this.directory && that.directory) != that.directory) {
 return false;
 }
 // Same npath is good as long as both or neither are directories
 if (this.npath.equals(that.npath)
 && this.directory == that.directory) {
 return true;
 }
 int diff = containsPath(this.npath, that.npath);
 // Right inside left is good if recursive
 if (diff >= 1 && recursive) {
 return true;
 }
 // Right right inside left if it is element in set
 if (diff == 1 && directory && !that.directory) {
 return true;
 }

 // Hack: if a npath2 field exists, apply the same checks
 // on it as a fallback.
 if (this.npath2 != null) {
 if (this.npath2.equals(that.npath)
 && this.directory == that.directory) {
 return true;
 }
 diff = containsPath(this.npath2, that.npath);
 if (diff >= 1 && recursive) {
 return true;
 }
 if (diff == 1 && directory && !that.directory) {
 return true;
 }
 }

 return false;
 } else {
 if (this.directory) {
 if (this.recursive) {
 // make sure that.path is longer then path so
 // something like /foo/- does not imply /foo
 if (that.directory) {
 return (that.cpath.length() >= this.cpath.length()) &&
 that.cpath.startsWith(this.cpath);
 } else {
 return ((that.cpath.length() > this.cpath.length()) &&
 that.cpath.startsWith(this.cpath));
 }
 } else {
 if (that.directory) {
 // if the permission passed in is a directory
 // specification, make sure that a non-recursive
 // permission (i.e., this object) can't imply a recursive
 // permission.
 if (that.recursive)
 return false;
 else
 return (this.cpath.equals(that.cpath));
 } else {
 int last = that.cpath.lastIndexOf(File.separatorChar);
 if (last == -1)
 return false;
 else {
 // this.cpath.equals(that.cpath.substring(0, last+1));
 // Use regionMatches to avoid creating new string
 return (this.cpath.length() == (last + 1)) &&
 this.cpath.regionMatches(0, that.cpath, 0, last + 1);
 }
 }
 }
 } else if (that.directory) {
 // if this is NOT recursive/wildcarded,
 // do not let it imply a recursive/wildcarded permission
 return false;
 } else {
 return (this.cpath.equals(that.cpath));
 }
 }
 }

 /**
 * Returns the depth between an outer path p1 and an inner path p2. -1
 * is returned if
 *
 * - p1 does not contains p2.
 * - this is not decidable. For example, p1="../x", p2="y".
 * - the depth is not decidable. For example, p1="/", p2="x".
 *
 * This method can return 2 if the depth is greater than 2.
 *
 * @param p1 the expected outer path, normalized
 * @param p2 the expected inner path, normalized
 * @return the depth in between
 */
 private static int containsPath(Path p1, Path p2) {

 // Two paths must have the same root. For example,
 // there is no contains relation between any two of
 // "/x", "x", "C:/x", "C:x", and "//host/share/x".
 if (!Objects.equals(p1.getRoot(), p2.getRoot())) {
 return -1;
 }

 // Empty path (i.e. "." or "") is a strange beast,
 // because its getNameCount()==1 but getName(0) is null.
 // It's better to deal with it separately.
 if (p1.equals(EMPTY_PATH)) {
 if (p2.equals(EMPTY_PATH)) {
 return 0;
 } else if (p2.getName(0).equals(DOTDOT_PATH)) {
 // "." contains p2 iff p2 has no "..". Since
 // a normalized path can only have 0 or more
 // ".." at the beginning. We only need to look
 // at the head.
 return -1;
 } else {
 // and the distance is p2's name count. i.e.
 // 3 between "." and "a/b/c".
 return p2.getNameCount();
 }
 } else if (p2.equals(EMPTY_PATH)) {
 int c1 = p1.getNameCount();
 if (!p1.getName(c1 - 1).equals(DOTDOT_PATH)) {
 // "." is inside p1 iff p1 is 1 or more "..".
 // For the same reason above, we only need to
 // look at the tail.
 return -1;
 }
 // and the distance is the count of ".."
 return c1;
 }

 // Good. No more empty paths.

 // Common heads are removed

 int c1 = p1.getNameCount();
 int c2 = p2.getNameCount();

 int n = Math.min(c1, c2);
 int i = 0;
 while (i < n) {
 if (!p1.getName(i).equals(p2.getName(i)))
 break;
 i++;
 }

 // for p1 containing p2, p1 must be 0-or-more "..",
 // and p2 cannot have "..". For the same reason, we only
 // check tail of p1 and head of p2.
 if (i < c1 && !p1.getName(c1 - 1).equals(DOTDOT_PATH)) {
 return -1;
 }

 if (i < c2 && p2.getName(i).equals(DOTDOT_PATH)) {
 return -1;
 }

 // and the distance is the name counts added (after removing
 // the common heads).

 // For example: p1 = "../../..", p2 = "../a".
 // After removing the common heads, they become "../.." and "a",
 // and the distance is (3-1)+(2-1) = 3.
 return c1 - i + c2 - i;
 }

 /**
 * Checks two FilePermission objects for equality. Checks that <i>obj</i> is
 * a FilePermission, and has the same pathname and actions as this object.
 *
 * @implNote More specifically, two pathnames are the same if and only if
 * they have the same wildcard flag and their {@code cpath}
 * (if {@code jdk.io.permissionsUseCanonicalPath} is {@code true}) or
 * {@code npath} (if {@code jdk.io.permissionsUseCanonicalPath}
 * is {@code false}) are equal. Or they are both {@literal "<<ALL FILES>>"}.
 * <p>
 * When {@code jdk.io.permissionsUseCanonicalPath} is {@code false}, an
 * invalid {@code FilePermission} does not equal to any object except
 * for itself, even if they are created using the same invalid path.
 *
 * @param obj the object we are testing for equality with this object.
 * @return <code>true</code> if obj is a FilePermission, and has the same
 * pathname and actions as this FilePermission object,
 * <code>false</code> otherwise.
 */
 @Override
 public boolean equals(Object obj) {
 if (obj == this)
 return true;

 if (! (obj instanceof FilePermission))
 return false;

 FilePermission that = (FilePermission) obj;

 if (FilePermCompat.nb) {
 if (this.invalid || that.invalid) {
 return false;
 }
 return (this.mask == that.mask) &&
 (this.allFiles == that.allFiles) &&
 this.npath.equals(that.npath) &&
 Objects.equals(npath2, that.npath2) &&
 (this.directory == that.directory) &&
 (this.recursive == that.recursive);
 } else {
 return (this.mask == that.mask) &&
 this.cpath.equals(that.cpath) &&
 (this.directory == that.directory) &&
 (this.recursive == that.recursive);
 }
 }

 /**
 * Returns the hash code value for this object.
 *
 * @return a hash code value for this object.
 */
 @Override
 public int hashCode() {
 if (FilePermCompat.nb) {
 return Objects.hash(
 mask, allFiles, directory, recursive, npath, npath2, invalid);
 } else {
 return 0;
 }
 }

 /**
 * Converts an actions String to an actions mask.
 *
 * @param actions the action string.
 * @return the actions mask.
 */
 private static int getMask(String actions) {
 int mask = NONE;

 // Null action valid?
 if (actions == null) {
 return mask;
 }

 // Use object identity comparison against known-interned strings for
 // performance benefit (these values are used heavily within the JDK).
 if (actions == SecurityConstants.FILE_READ_ACTION) {
 return READ;
 } else if (actions == SecurityConstants.FILE_WRITE_ACTION) {
 return WRITE;
 } else if (actions == SecurityConstants.FILE_EXECUTE_ACTION) {
 return EXECUTE;
 } else if (actions == SecurityConstants.FILE_DELETE_ACTION) {
 return DELETE;
 } else if (actions == SecurityConstants.FILE_READLINK_ACTION) {
 return READLINK;
 }

 char[] a = actions.toCharArray();

 int i = a.length - 1;
 if (i < 0)
 return mask;

 while (i != -1) {
 char c;

 // skip whitespace
 while ((i!=-1) && ((c = a[i]) == ' ' ||
 c == '\r' ||
 c == '\n' ||
 c == '\f' ||
 c == '\t'))
 i--;

 // check for the known strings
 int matchlen;

 if (i >= 3 && (a[i-3] == 'r' || a[i-3] == 'R') &&
 (a[i-2] == 'e' || a[i-2] == 'E') &&
 (a[i-1] == 'a' || a[i-1] == 'A') &&
 (a[i] == 'd' || a[i] == 'D'))
 {
 matchlen = 4;
 mask |= READ;

 } else if (i >= 4 && (a[i-4] == 'w' || a[i-4] == 'W') &&
 (a[i-3] == 'r' || a[i-3] == 'R') &&
 (a[i-2] == 'i' || a[i-2] == 'I') &&
 (a[i-1] == 't' || a[i-1] == 'T') &&
 (a[i] == 'e' || a[i] == 'E'))
 {
 matchlen = 5;
 mask |= WRITE;

 } else if (i >= 6 && (a[i-6] == 'e' || a[i-6] == 'E') &&
 (a[i-5] == 'x' || a[i-5] == 'X') &&
 (a[i-4] == 'e' || a[i-4] == 'E') &&
 (a[i-3] == 'c' || a[i-3] == 'C') &&
 (a[i-2] == 'u' || a[i-2] == 'U') &&
 (a[i-1] == 't' || a[i-1] == 'T') &&
 (a[i] == 'e' || a[i] == 'E'))
 {
 matchlen = 7;
 mask |= EXECUTE;

 } else if (i >= 5 && (a[i-5] == 'd' || a[i-5] == 'D') &&
 (a[i-4] == 'e' || a[i-4] == 'E') &&
 (a[i-3] == 'l' || a[i-3] == 'L') &&
 (a[i-2] == 'e' || a[i-2] == 'E') &&
 (a[i-1] == 't' || a[i-1] == 'T') &&
 (a[i] == 'e' || a[i] == 'E'))
 {
 matchlen = 6;
 mask |= DELETE;

 } else if (i >= 7 && (a[i-7] == 'r' || a[i-7] == 'R') &&
 (a[i-6] == 'e' || a[i-6] == 'E') &&
 (a[i-5] == 'a' || a[i-5] == 'A') &&
 (a[i-4] == 'd' || a[i-4] == 'D') &&
 (a[i-3] == 'l' || a[i-3] == 'L') &&
 (a[i-2] == 'i' || a[i-2] == 'I') &&
 (a[i-1] == 'n' || a[i-1] == 'N') &&
 (a[i] == 'k' || a[i] == 'K'))
 {
 matchlen = 8;
 mask |= READLINK;

 } else {
 // parse error
 throw new IllegalArgumentException(
 "invalid permission: " + actions);
 }

 // make sure we didn't just match the tail of a word
 // like "ackbarfaccept". Also, skip to the comma.
 boolean seencomma = false;
 while (i >= matchlen && !seencomma) {
 switch(a[i-matchlen]) {
 case ',':
 seencomma = true;
 break;
 case ' ': case '\r': case '\n':
 case '\f': case '\t':
 break;
 default:
 throw new IllegalArgumentException(
 "invalid permission: " + actions);
 }
 i--;
 }

 // point i at the location of the comma minus one (or -1).
 i -= matchlen;
 }

 return mask;
 }

 /**
 * Return the current action mask. Used by the FilePermissionCollection.
 *
 * @return the actions mask.
 */
 int getMask() {
 return mask;
 }

 /**
 * Return the canonical string representation of the actions.
 * Always returns present actions in the following order:
 * read, write, execute, delete, readlink.
 *
 * @return the canonical string representation of the actions.
 */
 private static String getActions(int mask) {
 StringJoiner sj = new StringJoiner(",");

 if ((mask & READ) == READ) {
 sj.add("read");
 }
 if ((mask & WRITE) == WRITE) {
 sj.add("write");
 }
 if ((mask & EXECUTE) == EXECUTE) {
 sj.add("execute");
 }
 if ((mask & DELETE) == DELETE) {
 sj.add("delete");
 }
 if ((mask & READLINK) == READLINK) {
 sj.add("readlink");
 }

 return sj.toString();
 }

 /**
 * Returns the "canonical string representation" of the actions.
 * That is, this method always returns present actions in the following order:
 * read, write, execute, delete, readlink. For example, if this FilePermission
 * object allows both write and read actions, a call to <code>getActions</code>
 * will return the string "read,write".
 *
 * @return the canonical string representation of the actions.
 */
 @Override
 public String getActions() {
 if (actions == null)
 actions = getActions(this.mask);

 return actions;
 }

 /**
 * Returns a new PermissionCollection object for storing FilePermission
 * objects.
 * <p>
 * FilePermission objects must be stored in a manner that allows them
 * to be inserted into the collection in any order, but that also enables the
 * PermissionCollection <code>implies</code>
 * method to be implemented in an efficient (and consistent) manner.
 *
 * <p>For example, if you have two FilePermissions:
 * <OL>
 * <LI> <code>"/tmp/-", "read"</code>
 * <LI> <code>"/tmp/scratch/foo", "write"</code>
 * </OL>
 *
 * <p>and you are calling the <code>implies</code> method with the FilePermission:
 *
 * <pre>
 * "/tmp/scratch/foo", "read,write",
 * </pre>
 *
 * then the <code>implies</code> function must
 * take into account both the "/tmp/-" and "/tmp/scratch/foo"
 * permissions, so the effective permission is "read,write",
 * and <code>implies</code> returns true. The "implies" semantics for
 * FilePermissions are handled properly by the PermissionCollection object
 * returned by this <code>newPermissionCollection</code> method.
 *
 * @return a new PermissionCollection object suitable for storing
 * FilePermissions.
 */
 @Override
 public PermissionCollection newPermissionCollection() {
 return new FilePermissionCollection();
 }

 /**
 * WriteObject is called to save the state of the FilePermission
 * to a stream. The actions are serialized, and the superclass
 * takes care of the name.
 */
 private void writeObject(ObjectOutputStream s)
 throws IOException
 {
 // Write out the actions. The superclass takes care of the name
 // call getActions to make sure actions field is initialized
 if (actions == null)
 getActions();
 s.defaultWriteObject();
 }

 /**
 * readObject is called to restore the state of the FilePermission from
 * a stream.
 */
 private void readObject(ObjectInputStream s)
 throws IOException, ClassNotFoundException
 {
 // Read in the actions, then restore everything else by calling init.
 s.defaultReadObject();
 init(getMask(actions));
 }

 /**
 * Create a cloned FilePermission with a different actions.
 * @param effective the new actions
 * @return a new object
 */
 FilePermission withNewActions(int effective) {
 return new FilePermission(this.getName(),
 this,
 this.npath,
 this.npath2,
 effective,
 null);
 }
}

/**
 * A FilePermissionCollection stores a set of FilePermission permissions.
 * FilePermission objects
 * must be stored in a manner that allows them to be inserted in any
 * order, but enable the implies function to evaluate the implies
 * method.
 * For example, if you have two FilePermissions:
 * <OL>
 * <LI> "/tmp/-", "read"
 * <LI> "/tmp/scratch/foo", "write"
 * </OL>
 * And you are calling the implies function with the FilePermission:
 * "/tmp/scratch/foo", "read,write", then the implies function must
 * take into account both the /tmp/- and /tmp/scratch/foo
 * permissions, so the effective permission is "read,write".
 *
 * @see java.security.Permission
 * @see java.security.Permissions
 * @see java.security.PermissionCollection
 *
 *
 * @author Marianne Mueller
 * @author Roland Schemers
 *
 * @serial include
 *
 */

final class FilePermissionCollection extends PermissionCollection
 implements Serializable
{
 // Not serialized; see serialization section at end of class
 private transient ConcurrentHashMap<String, Permission> perms;

 /**
 * Create an empty FilePermissionCollection object.
 */
 public FilePermissionCollection() {
 perms = new ConcurrentHashMap<>();
 }

 /**
 * Adds a permission to the FilePermissionCollection. The key for the hash is
 * permission.path.
 *
 * @param permission the Permission object to add.
 *
 * @exception IllegalArgumentException - if the permission is not a
 * FilePermission
 *
 * @exception SecurityException - if this FilePermissionCollection object
 * has been marked readonly
 */
 @Override
 public void add(Permission permission) {
 if (! (permission instanceof FilePermission))
 throw new IllegalArgumentException("invalid permission: "+
 permission);
 if (isReadOnly())
 throw new SecurityException(
 "attempt to add a Permission to a readonly PermissionCollection");

 FilePermission fp = (FilePermission)permission;

 // Add permission to map if it is absent, or replace with new
 // permission if applicable.
 perms.merge(fp.getName(), fp,
 new java.util.function.BiFunction<>() {
 @Override
 public Permission apply(Permission existingVal,
 Permission newVal) {
 int oldMask = ((FilePermission)existingVal).getMask();
 int newMask = ((FilePermission)newVal).getMask();
 if (oldMask != newMask) {
 int effective = oldMask | newMask;
 if (effective == newMask) {
 return newVal;
 }
 if (effective != oldMask) {
 return ((FilePermission)newVal)
 .withNewActions(effective);
 }
 }
 return existingVal;
 }
 }
 );
 }

 /**
 * Check and see if this set of permissions implies the permissions
 * expressed in "permission".
 *
 * @param permission the Permission object to compare
 *
 * @return true if "permission" is a proper subset of a permission in
 * the set, false if not.
 */
 @Override
 public boolean implies(Permission permission) {
 if (! (permission instanceof FilePermission))
 return false;

 FilePermission fperm = (FilePermission) permission;

 int desired = fperm.getMask();
 int effective = 0;
 int needed = desired;

 for (Permission perm : perms.values()) {
 FilePermission fp = (FilePermission)perm;
 if (((needed & fp.getMask()) != 0) && fp.impliesIgnoreMask(fperm)) {
 effective |= fp.getMask();
 if ((effective & desired) == desired) {
 return true;
 }
 needed = (desired ^ effective);
 }
 }
 return false;
 }

 /**
 * Returns an enumeration of all the FilePermission objects in the
 * container.
 *
 * @return an enumeration of all the FilePermission objects.
 */
 @Override
 public Enumeration<Permission> elements() {
 return perms.elements();
 }

 private static final long serialVersionUID = 2202956749081564585L;

 // Need to maintain serialization interoperability with earlier releases,
 // which had the serializable field:
 // private Vector permissions;

 /**
 * @serialField permissions java.util.Vector
 * A list of FilePermission objects.
 */
 private static final ObjectStreamField[] serialPersistentFields = {
 new ObjectStreamField("permissions", Vector.class),
 };

 /**
 * @serialData "permissions" field (a Vector containing the FilePermissions).
 */
 /*
 * Writes the contents of the perms field out as a Vector for
 * serialization compatibility with earlier releases.
 */
 private void writeObject(ObjectOutputStream out) throws IOException {
 // Don't call out.defaultWriteObject()

 // Write out Vector
 Vector<Permission> permissions = new Vector<>(perms.values());

 ObjectOutputStream.PutField pfields = out.putFields();
 pfields.put("permissions", permissions);
 out.writeFields();
 }

 /*
 * Reads in a Vector of FilePermissions and saves them in the perms field.
 */
 private void readObject(ObjectInputStream in)
 throws IOException, ClassNotFoundException
 {
 // Don't call defaultReadObject()

 // Read in serialized fields
 ObjectInputStream.GetField gfields = in.readFields();

 // Get the one we want
 @SuppressWarnings("unchecked")
 Vector<Permission> permissions = (Vector<Permission>)gfields.get("permissions", null);
 perms = new ConcurrentHashMap<>(permissions.size());
 for (Permission perm : permissions) {
 perms.put(perm.getName(), perm);
 }
 }
}