/*

 * Copyright 2008-2009 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.nio.fs;

import java.nio.file.attribute.*;

import java.io.IOException;

import static sun.nio.fs.UnixNativeDispatcher.*;

/**

 * Unix implementation of java.nio.file.attribute.UserPrincipal

 */

class UnixUserPrincipals {

    private static User createSpecial(String name) { return new User(-1, name); }

    static final User SPECIAL_OWNER = createSpecial("OWNER@");

    static final User SPECIAL_GROUP = createSpecial("GROUP@");

    static final User SPECIAL_EVERYONE = createSpecial("EVERYONE@");

    static class User implements UserPrincipal {

        private final int id;             // uid or gid

        private final boolean isGroup;

        private final String name;

        private User(int id, boolean isGroup, String name) {

            this.id = id;

            this.isGroup = isGroup;

            this.name = name;

        }

        User(int id, String name) {

            this(id, false, name);

        }

        int uid() {

            if (isGroup)

                throw new AssertionError();

            return id;

        }

        int gid() {

            if (isGroup)

                return id;

            throw new AssertionError();

        }

        boolean isSpecial() {

            return id == -1;

        }

        @Override

        public String getName() {

            return name;

        }

        @Override

        public String toString() {

            return name;

        }

        @Override

        public boolean equals(Object obj) {

            if (obj == this)

                return true;

            if (!(obj instanceof User))

                return false;

            User other = (User)obj;

            if ((this.id != other.id) ||

                (this.isGroup != other.isGroup)) {

                return false;

            }

            // specials

            if (this.id == -1 && other.id == -1)

                return this.name.equals(other.name);

            return true;

        }

        @Override

        public int hashCode() {

            return (id != -1) ? id : name.hashCode();

        }

    }

    static class Group extends User implements GroupPrincipal {

        Group(int id, String name) {

            super(id, true, name);

        }

    }

    // return UserPrincipal representing given uid

    static User fromUid(int uid) {

        String name = null;

        try {

            name = new String(getpwuid(uid));

        } catch (UnixException x) {

            name = Integer.toString(uid);

        }

        return new User(uid, name);

    }

    // return GroupPrincipal representing given gid

    static Group fromGid(int gid) {

        String name = null;

        try {

            name = new String(getgrgid(gid));

        } catch (UnixException x) {

            name = Integer.toString(gid);

        }

        return new Group(gid, name);

    }

    // lookup user or group name

    private static int lookupName(String name, boolean isGroup)

        throws IOException

    {

        SecurityManager sm = System.getSecurityManager();

        if (sm != null) {

            sm.checkPermission(new RuntimePermission("lookupUserInformation"));

        }

        int id = -1;

        try {

            id = (isGroup) ? getgrnam(name) : getpwnam(name);

        } catch (UnixException x) {

            throw new IOException(name + ": " + x.errorString());

        }

        if (id == -1)

            throw new UserPrincipalNotFoundException(name);

        return id;

    }

    // lookup user name

    static UserPrincipal lookupUser(String name) throws IOException {

        if (name.equals(SPECIAL_OWNER.getName()))

            return SPECIAL_OWNER;

        if (name.equals(SPECIAL_GROUP.getName()))

            return SPECIAL_GROUP;

        if (name.equals(SPECIAL_EVERYONE.getName()))

            return SPECIAL_EVERYONE;

        int uid = lookupName(name, false);

        return new User(uid, name);

    }

    // lookup group name

    static GroupPrincipal lookupGroup(String group)

        throws IOException

    {

        int gid = lookupName(group, true);

        return new Group(gid, group);

    }

}