406 lines
11 KiB
Java
406 lines
11 KiB
Java
/*
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* This file is part of ComputerCraft - http://www.computercraft.info
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* Copyright Daniel Ratcliffe, 2011-2019. Do not distribute without permission.
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* Send enquiries to dratcliffe@gmail.com
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*/
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package dan200.computercraft.core.filesystem;
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import com.google.common.collect.Sets;
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import dan200.computercraft.api.filesystem.FileOperationException;
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import dan200.computercraft.api.filesystem.IWritableMount;
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import javax.annotation.Nonnull;
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import java.io.*;
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import java.nio.ByteBuffer;
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import java.nio.channels.*;
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import java.nio.file.Files;
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import java.nio.file.OpenOption;
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import java.nio.file.StandardOpenOption;
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import java.util.Collections;
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import java.util.List;
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import java.util.Set;
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public class FileMount implements IWritableMount
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{
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private static final int MINIMUM_FILE_SIZE = 500;
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private static final Set<OpenOption> READ_OPTIONS = Collections.singleton( StandardOpenOption.READ );
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private static final Set<OpenOption> WRITE_OPTIONS = Sets.newHashSet( StandardOpenOption.WRITE, StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING );
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private static final Set<OpenOption> APPEND_OPTIONS = Sets.newHashSet( StandardOpenOption.WRITE, StandardOpenOption.CREATE, StandardOpenOption.APPEND );
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private class WritableCountingChannel implements WritableByteChannel
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{
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private final WritableByteChannel m_inner;
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long m_ignoredBytesLeft;
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WritableCountingChannel( WritableByteChannel inner, long bytesToIgnore )
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{
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m_inner = inner;
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m_ignoredBytesLeft = bytesToIgnore;
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}
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@Override
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public int write( @Nonnull ByteBuffer b ) throws IOException
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{
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count( b.remaining() );
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return m_inner.write( b );
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}
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void count( long n ) throws IOException
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{
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m_ignoredBytesLeft -= n;
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if( m_ignoredBytesLeft < 0 )
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{
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long newBytes = -m_ignoredBytesLeft;
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m_ignoredBytesLeft = 0;
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long bytesLeft = m_capacity - m_usedSpace;
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if( newBytes > bytesLeft ) throw new IOException( "Out of space" );
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m_usedSpace += newBytes;
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}
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}
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@Override
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public boolean isOpen()
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{
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return m_inner.isOpen();
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}
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@Override
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public void close() throws IOException
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{
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m_inner.close();
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}
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}
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private class SeekableCountingChannel extends WritableCountingChannel implements SeekableByteChannel
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{
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private final SeekableByteChannel m_inner;
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SeekableCountingChannel( SeekableByteChannel inner, long bytesToIgnore )
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{
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super( inner, bytesToIgnore );
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m_inner = inner;
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}
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@Override
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public SeekableByteChannel position( long newPosition ) throws IOException
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{
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if( !isOpen() ) throw new ClosedChannelException();
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if( newPosition < 0 )
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{
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throw new IllegalArgumentException( "Cannot seek before the beginning of the stream" );
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}
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long delta = newPosition - m_inner.position();
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if( delta < 0 )
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{
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m_ignoredBytesLeft -= delta;
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}
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else
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{
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count( delta );
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}
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return m_inner.position( newPosition );
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}
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@Override
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public SeekableByteChannel truncate( long size ) throws IOException
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{
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throw new IOException( "Not yet implemented" );
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}
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@Override
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public int read( ByteBuffer dst ) throws ClosedChannelException
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{
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if( !m_inner.isOpen() ) throw new ClosedChannelException();
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throw new NonReadableChannelException();
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}
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@Override
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public long position() throws IOException
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{
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return m_inner.position();
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}
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@Override
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public long size() throws IOException
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{
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return m_inner.size();
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}
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}
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private File m_rootPath;
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private long m_capacity;
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private long m_usedSpace;
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public FileMount( File rootPath, long capacity )
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{
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m_rootPath = rootPath;
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m_capacity = capacity + MINIMUM_FILE_SIZE;
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m_usedSpace = created() ? measureUsedSpace( m_rootPath ) : MINIMUM_FILE_SIZE;
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}
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// IMount implementation
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@Override
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public boolean exists( @Nonnull String path )
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{
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if( !created() ) return path.isEmpty();
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File file = getRealPath( path );
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return file.exists();
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}
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@Override
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public boolean isDirectory( @Nonnull String path )
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{
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if( !created() ) return path.isEmpty();
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File file = getRealPath( path );
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return file.exists() && file.isDirectory();
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}
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@Override
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public void list( @Nonnull String path, @Nonnull List<String> contents ) throws IOException
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{
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if( !created() )
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{
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if( !path.isEmpty() ) throw new FileOperationException( path, "Not a directory" );
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return;
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}
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File file = getRealPath( path );
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if( !file.exists() || !file.isDirectory() ) throw new FileOperationException( path, "Not a directory" );
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String[] paths = file.list();
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for( String subPath : paths )
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{
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if( new File( file, subPath ).exists() ) contents.add( subPath );
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}
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}
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@Override
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public long getSize( @Nonnull String path ) throws IOException
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{
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if( !created() )
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{
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if( path.isEmpty() ) return 0;
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}
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else
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{
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File file = getRealPath( path );
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if( file.exists() ) return file.isDirectory() ? 0 : file.length();
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}
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throw new FileOperationException( path, "No such file" );
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}
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@Nonnull
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@Override
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@Deprecated
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public InputStream openForRead( @Nonnull String path ) throws IOException
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{
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if( created() )
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{
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File file = getRealPath( path );
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if( file.exists() && !file.isDirectory() ) return new FileInputStream( file );
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}
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throw new FileOperationException( path, "No such file" );
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}
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@Nonnull
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@Override
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public ReadableByteChannel openChannelForRead( @Nonnull String path ) throws IOException
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{
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if( created() )
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{
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File file = getRealPath( path );
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if( file.exists() && !file.isDirectory() ) return FileChannel.open( file.toPath(), READ_OPTIONS );
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}
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throw new FileOperationException( path, "No such file" );
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}
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// IWritableMount implementation
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@Override
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public void makeDirectory( @Nonnull String path ) throws IOException
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{
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create();
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File file = getRealPath( path );
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if( file.exists() )
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{
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if( !file.isDirectory() ) throw new FileOperationException( path, "File exists" );
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return;
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}
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int dirsToCreate = 1;
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File parent = file.getParentFile();
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while( !parent.exists() )
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{
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++dirsToCreate;
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parent = parent.getParentFile();
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}
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if( getRemainingSpace() < dirsToCreate * MINIMUM_FILE_SIZE )
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{
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throw new FileOperationException( path, "Out of space" );
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}
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if( file.mkdirs() )
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{
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m_usedSpace += dirsToCreate * MINIMUM_FILE_SIZE;
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}
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else
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{
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throw new FileOperationException( path, "Access denied" );
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}
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}
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@Override
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public void delete( @Nonnull String path ) throws IOException
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{
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if( path.isEmpty() ) throw new FileOperationException( path, "Access denied" );
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if( created() )
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{
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File file = getRealPath( path );
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if( file.exists() ) deleteRecursively( file );
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}
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}
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private void deleteRecursively( File file ) throws IOException
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{
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// Empty directories first
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if( file.isDirectory() )
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{
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String[] children = file.list();
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for( String aChildren : children )
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{
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deleteRecursively( new File( file, aChildren ) );
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}
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}
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// Then delete
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long fileSize = file.isDirectory() ? 0 : file.length();
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boolean success = file.delete();
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if( success )
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{
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m_usedSpace -= Math.max( MINIMUM_FILE_SIZE, fileSize );
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}
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else
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{
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throw new IOException( "Access denied" );
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}
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}
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@Nonnull
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@Override
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@Deprecated
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public OutputStream openForWrite( @Nonnull String path ) throws IOException
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{
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return Channels.newOutputStream( openChannelForWrite( path ) );
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}
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@Nonnull
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@Override
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@Deprecated
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public OutputStream openForAppend( @Nonnull String path ) throws IOException
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{
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return Channels.newOutputStream( openChannelForAppend( path ) );
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}
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@Nonnull
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@Override
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public WritableByteChannel openChannelForWrite( @Nonnull String path ) throws IOException
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{
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create();
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File file = getRealPath( path );
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if( file.exists() && file.isDirectory() ) throw new FileOperationException( path, "Cannot write to directory" );
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if( file.exists() )
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{
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m_usedSpace -= Math.max( file.length(), MINIMUM_FILE_SIZE );
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}
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else if( getRemainingSpace() < MINIMUM_FILE_SIZE )
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{
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throw new FileOperationException( path, "Out of space" );
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}
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m_usedSpace += MINIMUM_FILE_SIZE;
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return new SeekableCountingChannel( Files.newByteChannel( file.toPath(), WRITE_OPTIONS ), MINIMUM_FILE_SIZE );
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}
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@Nonnull
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@Override
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public WritableByteChannel openChannelForAppend( @Nonnull String path ) throws IOException
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{
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if( !created() )
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{
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throw new FileOperationException( path, "No such file" );
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}
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File file = getRealPath( path );
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if( !file.exists() ) throw new FileOperationException( path, "No such file" );
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if( file.isDirectory() ) throw new FileOperationException( path, "Cannot write to directory" );
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// Allowing seeking when appending is not recommended, so we use a separate channel.
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return new WritableCountingChannel(
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Files.newByteChannel( file.toPath(), APPEND_OPTIONS ),
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Math.max( MINIMUM_FILE_SIZE - file.length(), 0 )
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);
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}
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@Override
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public long getRemainingSpace()
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{
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return Math.max( m_capacity - m_usedSpace, 0 );
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}
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private File getRealPath( String path )
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{
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return new File( m_rootPath, path );
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}
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private boolean created()
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{
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return m_rootPath.exists();
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}
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private void create() throws IOException
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{
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if( !m_rootPath.exists() )
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{
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boolean success = m_rootPath.mkdirs();
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if( !success )
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{
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throw new IOException( "Access denied" );
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}
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}
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}
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private static long measureUsedSpace( File file )
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{
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if( !file.exists() ) return 0;
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if( file.isDirectory() )
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{
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long size = MINIMUM_FILE_SIZE;
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String[] contents = file.list();
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for( String content : contents )
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{
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size += measureUsedSpace( new File( file, content ) );
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}
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return size;
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}
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else
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{
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return Math.max( file.length(), MINIMUM_FILE_SIZE );
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}
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}
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}
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