/*

 * Copyright (c) 2011, 2012, 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.util.prefs;

import java.util.Objects;

class MacOSXPreferences extends AbstractPreferences {

    // fixme need security checks?

    // CF preferences file name for Java nodes with short names

    // This value is also in MacOSXPreferencesFile.c

    private static final String defaultAppName = "com.apple.java.util.prefs";

    // true if this node is a child of userRoot or is userRoot

    private final boolean isUser;

    // CF's storage location for this node and its keys

    private final MacOSXPreferencesFile file;

    // absolutePath() + "/"

    private final String path;

    // User root and system root nodes

    private static volatile MacOSXPreferences userRoot;

    private static volatile MacOSXPreferences systemRoot;

    // Returns user root node, creating it if necessary.

    // Called by MacOSXPreferencesFactory

    static Preferences getUserRoot() {

        MacOSXPreferences root = userRoot;

        if (root == null) {

            synchronized (MacOSXPreferences.class) {

                root = userRoot;

                if (root == null) {

                    userRoot = root = new MacOSXPreferences(true);

                }

            }

        }

        return root;

    }

    // Returns system root node, creating it if necessary.

    // Called by MacOSXPreferencesFactory

    static Preferences getSystemRoot() {

        MacOSXPreferences root = systemRoot;

        if (root == null) {

            synchronized (MacOSXPreferences.class) {

                root = systemRoot;

                if (root == null) {

                    systemRoot = root = new MacOSXPreferences(false);

                }

            }

        }

        return root;

    }

    // Create a new root node. Called by getUserRoot() and getSystemRoot()

    // Synchronization is provided by the caller.

    private MacOSXPreferences(boolean newIsUser) {

        this(null, "", false, true, newIsUser);

    }

    // Create a new non-root node with the given parent.

    // Called by childSpi().

    private MacOSXPreferences(MacOSXPreferences parent, String name) {

        this(parent, name, false, false, false);

    }

    private MacOSXPreferences(MacOSXPreferences parent, String name,

                              boolean isNew)

    {

        this(parent, name, isNew, false, false);

    }

    private MacOSXPreferences(MacOSXPreferences parent, String name,

                              boolean isNew, boolean isRoot, boolean isUser)

    {

        super(parent, name);

        if (isRoot)

            this.isUser = isUser;

        else

            this.isUser = isUserNode();

        path = isRoot ? absolutePath() : absolutePath() + "/";

        file = cfFileForNode(this.isUser);

        if (isNew)

            newNode = isNew;

        else

            newNode = file.addNode(path);

    }

    // Create and return the MacOSXPreferencesFile for this node.

    // Does not write anything to the file.

    private MacOSXPreferencesFile cfFileForNode(boolean isUser)

    {

        String name = path;

        // /one/two/three/four/five/

        // The fourth slash is the end of the first three components.

        // If there is no fourth slash, the name has fewer than 3 components

        int pos = -1;

        for (int i = 0; i < 4; i++) {

            pos = name.indexOf('/', pos+1);

            if (pos == -1) break;

        }

        if (pos == -1) {

            // fewer than three components - use default name

            name = defaultAppName;

        } else {

            // truncate to three components, no leading or trailing '/'

            // replace '/' with '.' to make filesystem happy

            // convert to all lowercase to survive on HFS+

            name = name.substring(1, pos);

            name = name.replace('/', '.');

            name = name.toLowerCase();

        }

        return MacOSXPreferencesFile.getFile(name, isUser);

    }

    // AbstractPreferences implementation

    @Override

    protected void putSpi(String key, String value)

    {

        file.addKeyToNode(path, key, value);

    }

    // AbstractPreferences implementation

    @Override

    protected String getSpi(String key)

    {

        return file.getKeyFromNode(path, key);

    }

    // AbstractPreferences implementation

    @Override

    protected void removeSpi(String key)

    {

        Objects.requireNonNull(key, "Specified key cannot be null");

        file.removeKeyFromNode(path, key);

    }

    // AbstractPreferences implementation

    @Override

    protected void removeNodeSpi()

    throws BackingStoreException

    {

        // Disallow flush or sync between these two operations

        // (they may be manipulating two different files)

        synchronized(MacOSXPreferencesFile.class) {

            ((MacOSXPreferences)parent()).removeChild(name());

            file.removeNode(path);

        }

    }

    // Erase knowledge about a child of this node. Called by removeNodeSpi.

    private void removeChild(String child)

    {

        file.removeChildFromNode(path, child);

    }

    // AbstractPreferences implementation

    @Override

    protected String[] childrenNamesSpi()

    throws BackingStoreException

    {

        String[] result = file.getChildrenForNode(path);

        if (result == null) throw new BackingStoreException("Couldn't get list of children for node '" + path + "'");

        return result;

    }

    // AbstractPreferences implementation

    @Override

    protected String[] keysSpi()

    throws BackingStoreException

    {

        String[] result = file.getKeysForNode(path);

        if (result == null) throw new BackingStoreException("Couldn't get list of keys for node '" + path + "'");

        return result;

    }

    // AbstractPreferences implementation

    @Override

    protected AbstractPreferences childSpi(String name)

    {

        // Add to parent's child list here and disallow sync

        // because parent and child might be in different files.

        synchronized(MacOSXPreferencesFile.class) {

            boolean isNew = file.addChildToNode(path, name);

            return new MacOSXPreferences(this, name, isNew);

        }

    }

    // AbstractPreferences override

    @Override

    public void flush()

    throws BackingStoreException

    {

        // Flush should *not* check for removal, unlike sync, but should

        // prevent simultaneous removal.

        synchronized(lock) {

            if (isUser) {

                if (!MacOSXPreferencesFile.flushUser()) {

                    throw new BackingStoreException("Synchronization failed for node '" + path + "'");

                }

            } else {

                if (!MacOSXPreferencesFile.flushWorld()) {

                    throw new BackingStoreException("Synchronization failed for node '" + path + "'");

                }

            }

        }

    }

    // AbstractPreferences implementation

    @Override

    protected void flushSpi()

    throws BackingStoreException

    {

        // nothing here - overridden flush() doesn't call this

    }

    // AbstractPreferences override

    @Override

    public void sync()

    throws BackingStoreException

    {

        synchronized(lock) {

            if (isRemoved())

                throw new IllegalStateException("Node has been removed");

            // fixme! overkill

            if (isUser) {

                if (!MacOSXPreferencesFile.syncUser()) {

                    throw new BackingStoreException("Synchronization failed for node '" + path + "'");

                }

            } else {

                if (!MacOSXPreferencesFile.syncWorld()) {

                    throw new BackingStoreException("Synchronization failed for node '" + path + "'");

                }

            }

        }

    }

    // AbstractPreferences implementation

    @Override

    protected void syncSpi()

    throws BackingStoreException

    {

        // nothing here - overridden sync() doesn't call this

    }

}