/*

 * Copyright (c) 2019, 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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package jdk.jfr.internal;

import java.io.IOException;

import java.util.ArrayList;

import java.util.LinkedHashSet;

import java.util.Set;

import jdk.jfr.internal.SecuritySupport.SafePath;

// This class keeps track of files that can't be deleted

// so they can a later staged be removed.

final class FilePurger {

    private final static Set<SafePath> paths = new LinkedHashSet<>();

    public synchronized static void add(SafePath p) {

        paths.add(p);

        if (paths.size() > 1000) {

            removeOldest();

        }

    }

    public synchronized static void purge() {

        if (paths.isEmpty()) {

            return;

        }

        for (SafePath p : new ArrayList<>(paths)) {

            if (delete(p)) {

                paths.remove(p);

            }

        }

    }

    private static void removeOldest() {

        SafePath oldest = paths.iterator().next();

        paths.remove(oldest);

    }

    private static boolean delete(SafePath p) {

        try {

            SecuritySupport.delete(p);

            return true;

        } catch (IOException e) {

            return false;

        }

    }

}