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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.aliyun.fs.oss.utils;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.Path;

import java.io.File;
import java.util.Random;

public class Utils {
    static final Log LOG = LogFactory.getLog(Utils.class);
    public static synchronized File getTempBufferDir(Configuration conf) {
        String[] dataDirs = conf.get("dfs.datanode.data.dir", "file:///tmp/").split(",");
        double maxUsage = Double.MIN_VALUE;
        int n = 0;
        for(int i=0; i maxUsage) {
                n = i;
                maxUsage = diskUsage;
            }
        }

        // skip the disk whose free space is most not enough, and pick one randomly from the last disks.
        int idx;
        if (dataDirs.length == 1) {
            idx = 0;
        } else {
            while (true) {
                int i = Math.abs(new Random(System.currentTimeMillis()).nextInt()) % dataDirs.length;
                if (i != n) {
                    idx = i;
                    break;
                }
            }
        }

        String diskPath = new Path(dataDirs[idx].trim()).toUri().getPath();
        LOG.debug("choose oss buffer dir: "+diskPath);
        return new File(diskPath, "data/oss");

    }
}