/**
 * Copyright 2015 Palantir Technologies, Inc.
 *
 * 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.palantir.giraffe.internal;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.concurrent.Callable;

final class StreamCopier implements Callable<Void> {

    private static final int BUFFER_SIZE = 4096;

    private final InputStream source;
    private final OutputStream target;
    private final boolean flushAfterWrite;
    private final byte[] buffer;

    StreamCopier(InputStream source, OutputStream target) {
        this(source, target, false);
    }

    StreamCopier(InputStream source, OutputStream target, boolean flushAfterWrite) {
        this.source = source;
        this.target = target;
        this.flushAfterWrite = flushAfterWrite;

        buffer = new byte[BUFFER_SIZE];
    }

    @Override
    public Void call() throws IOException {
        while (true) {
            int r = source.read(buffer);
            if (r == -1) {
                break;
            }
            target.write(buffer, 0, r);
            if (flushAfterWrite) {
                target.flush();
            }
        }
        return null;
    }

}