Copyright Microsoft Corporation
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.
/**
 * Copyright Microsoft Corporation
 *
 * 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.microsoft.azure.storage.core;

import java.io.FileInputStream;
import java.io.FilterInputStream;
import java.io.IOException;
import java.nio.channels.FileChannel;

RESERVED FOR INTERNAL USE. Wraps a FileStream to allow for more memory efficient uploading.
/**
 * RESERVED FOR INTERNAL USE. Wraps a FileStream to allow for more memory efficient uploading.
 */
public final class MarkableFileStream extends FilterInputStream {
    private long mark = -1;
    private FileChannel fileChannel;

    public MarkableFileStream(FileInputStream stream) {
        super(stream);
        this.fileChannel = stream.getChannel();
    }

    @Override
    public synchronized void mark(int readlimit) {
        try {
            this.mark = this.fileChannel.position();
        }
        catch (IOException e) {
            this.mark = -1;
        }
    }

    @Override
    public synchronized void reset() throws IOException {
        if(this.mark == -1){
            throw new IOException("Stream must be marked before calling reset");
        }

        this.fileChannel.position(this.mark);
    }

    @Override
    public boolean markSupported() {
        return true;
    }
}