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;

		}

	}

}