com.facebook.presto.rakam.cache.MemoryMappedOrcDataSourceFactory.java Source code

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Here is the source code for com.facebook.presto.rakam.cache.MemoryMappedOrcDataSourceFactory.java

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/*
 * 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.facebook.presto.rakam.cache;

import com.facebook.presto.orc.AbstractOrcDataSource;
import com.facebook.presto.orc.OrcDataSource;
import com.facebook.presto.orc.OrcDataSourceId;
import com.facebook.presto.raptor.storage.ReaderAttributes;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.cache.Weigher;
import io.airlift.log.Logger;
import io.airlift.slice.Slice;
import io.airlift.slice.Slices;
import io.airlift.units.DataSize;

import javax.inject.Inject;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;

import static com.google.common.primitives.Ints.checkedCast;

public class MemoryMappedOrcDataSourceFactory implements OrcDataSourceFactory {
    private final LoadingCache<FileRegion, Slice> cache;
    private static final Logger logger = Logger.get(MemoryMappedOrcDataSourceFactory.class);

    @Inject
    public MemoryMappedOrcDataSourceFactory(CacheConfig config) {
        cache = CacheBuilder.newBuilder().maximumWeight(config.getDataSize().toBytes())
                .weigher(new Weigher<FileRegion, Slice>() {
                    @Override
                    public int weigh(FileRegion key, Slice value) {
                        return value.length();
                    }
                }).build(new CacheLoader<FileRegion, Slice>() {
                    public Slice load(FileRegion key) throws IOException {
                        if (!key.file.exists()) {
                            throw new FileNotFoundException(key.file.toString());
                        }

                        try (RandomAccessFile randomAccessFile = new RandomAccessFile(key.file, "r");
                                FileChannel channel = randomAccessFile.getChannel()) {
                            MappedByteBuffer byteBuffer = channel.map(FileChannel.MapMode.READ_ONLY, key.position,
                                    key.length);
                            return Slices.wrappedBuffer(byteBuffer);
                        }
                    }
                });
    }

    @Override
    public OrcDataSource create(ReaderAttributes readerAttributes, File file) throws FileNotFoundException {
        return new MemoryMappedOrcDataSource(file, readerAttributes.getMaxMergeDistance(),
                readerAttributes.getMaxReadSize(), readerAttributes.getStreamBufferSize());
    }

    public class MemoryMappedOrcDataSource extends AbstractOrcDataSource {
        private RandomAccessFile input;
        private final File file;

        public MemoryMappedOrcDataSource(File path, DataSize maxMergeDistance, DataSize maxReadSize,
                DataSize streamBufferSize) throws FileNotFoundException {
            super(new OrcDataSourceId(path.getPath()), path.length(), maxMergeDistance, maxReadSize,
                    streamBufferSize, true);
            this.file = path;
        }

        @Override
        public void close() throws IOException {
            if (input != null) {
                input.close();
            }
        }

        @Override
        protected void readInternal(long position, byte[] buffer, int bufferOffset, int bufferLength)
                throws IOException {
            try {
                Slice slice = cache.get(new FileRegion(file, position, bufferLength));
                slice.getBytes(0, buffer, bufferOffset, bufferLength);
            } catch (Exception e) {
                logger.warn(e, "Error file fetching file");

                if (input == null) {
                    this.input = new RandomAccessFile(file, "r");
                }
                input.seek(position);
                input.readFully(buffer, bufferOffset, bufferLength);
            }
        }
    }
}