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/*
 * Copyright 1999-2018 Alibaba Group Holding Ltd.
 *
 * Licensed 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.alibaba.nacos.client.config.utils;

import com.alibaba.nacos.api.common.Constants;

import java.io.*;
import java.util.ArrayList;
import java.util.List;

/**
 * IO Util
 *
 * @author Nacos
 */
@SuppressWarnings("PMD.ClassNamingShouldBeCamelRule")
public class IOUtils {

    static public String toString(InputStream input, String encoding) throws IOException {
        return (null == encoding) ? toString(new InputStreamReader(input, Constants.ENCODE))
            : toString(new InputStreamReader(input, encoding));
    }

    static public String toString(Reader reader) throws IOException {
        CharArrayWriter sw = new CharArrayWriter();
        copy(reader, sw);
        return sw.toString();
    }

    static public long copy(Reader input, Writer output) throws IOException {
        char[] buffer = new char[1 << 12];
        long count = 0;
        for (int n = 0; (n = input.read(buffer)) >= 0; ) {
            output.write(buffer, 0, n);
            count += n;
        }
        return count;
    }

    /**
     * 从输入流读行列表。保证不返回NULL。
     */
    static public List readLines(Reader input) throws IOException {
        BufferedReader reader = toBufferedReader(input);
        List list = new ArrayList();
        String line = null;
        for (; ; ) {
            line = reader.readLine();
            if (null != line) {
                list.add(line);
            } else {
                break;
            }
        }
        return list;
    }

    static private BufferedReader toBufferedReader(Reader reader) {
        return reader instanceof BufferedReader ? (BufferedReader)reader : new BufferedReader(
            reader);
    }

    public static void delete(File fileOrDir) throws IOException {
        if (fileOrDir == null) {
            return;
        }

        if (fileOrDir.isDirectory()) {
            cleanDirectory(fileOrDir);
        } else {
            if (fileOrDir.exists()) {
                boolean isDeleteOk = fileOrDir.delete();
                if (!isDeleteOk) {
                    throw new IOException("delete fail");
                }
            }
        }
    }

    /**
     * 清理目录下的内容
     */
    public static void cleanDirectory(File directory) throws IOException {
        if (!directory.exists()) {
            String message = directory + " does not exist";
            throw new IllegalArgumentException(message);
        }

        if (!directory.isDirectory()) {
            String message = directory + " is not a directory";
            throw new IllegalArgumentException(message);
        }

        File[] files = directory.listFiles();
        /**
         * null if security restricted
         */
        if (files == null) {
            throw new IOException("Failed to list contents of " + directory);
        }

        IOException exception = null;
        for (File file : files) {
            try {
                delete(file);
            } catch (IOException ioe) {
                exception = ioe;
            }
        }

        if (null != exception) {
            throw exception;
        }
    }

    public static void writeStringToFile(File file, String data, String encoding)
        throws IOException {
        OutputStream os = null;
        try {
            os = new FileOutputStream(file);
            os.write(data.getBytes(encoding));
        } finally {
            if (null != os) {
                os.close();
            }
        }
    }
}