70 lines
2.3 KiB
Java
70 lines
2.3 KiB
Java
package it.cavallium.strangedb.database.references;
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import it.cavallium.strangedb.database.DatabaseFileIO;
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import it.cavallium.strangedb.database.IReferencesIO;
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import java.io.IOException;
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import java.nio.ByteBuffer;
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import java.util.concurrent.locks.ReentrantReadWriteLock;
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public class DatabaseReferencesIO implements IReferencesIO {
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private final DatabaseFileIO fileIO;
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private final DatabaseReferencesMetadata referencesMetadata;
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public DatabaseReferencesIO(DatabaseFileIO fileIO, DatabaseReferencesMetadata referencesMetadata) {
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this.fileIO = fileIO;
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this.referencesMetadata = referencesMetadata;
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}
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@Override
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public long allocateReference() throws IOException {
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return referencesMetadata.newReference(0, 0);
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}
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@Override
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public long allocateReference(int size, ByteBuffer data) throws IOException {
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long index = writeToFile(size, data);
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return referencesMetadata.newReference(index, size);
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}
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@Override
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public void writeToReference(long reference, byte cleanerId, int size, ByteBuffer data) throws IOException {
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long index = writeToFile(size, data);
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referencesMetadata.editReference(reference, new ReferenceInfo(index, size, cleanerId));
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}
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@Override
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public ByteBuffer readFromReference(long reference) throws IOException {
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ReferenceInfo referenceInfo = referencesMetadata.getReferenceInfo(reference);
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return fileIO.readAt(referenceInfo.getIndex(), referenceInfo.getSize());
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}
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public ByteBuffer readFromReferenceSizeAndLastElementOfReferencesList(long reference) throws IOException {
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ReferenceInfo referenceInfo = referencesMetadata.getReferenceInfo(reference);
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if (referenceInfo.getSize() >= Integer.BYTES * 2 + Long.BYTES) {
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return fileIO.readAt(referenceInfo.getIndex() + referenceInfo.getSize() - (Integer.BYTES + Long.BYTES), Integer.BYTES + Long.BYTES);
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} else {
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return fileIO.readAt(referenceInfo.getIndex(), referenceInfo.getSize());
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}
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}
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/**
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*
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* @param size
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* @param data
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* @return index
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* @throws IOException
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*/
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private long writeToFile(int size, ByteBuffer data) throws IOException {
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if (size == 0 && data == null) return 0;
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if (size < 0) {
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throw new IOException("Trying to create a block with size " + size);
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}
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if (data.limit() < size) {
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throw new IOException("Trying to create a block with size " + size + " but with a buffer of size " + data.limit());
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}
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return fileIO.writeAtEnd(size, data);
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}
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}
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