387 lines
9.7 KiB
Java
387 lines
9.7 KiB
Java
/**
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* This file is part of ComputerCraft - http://www.computercraft.info
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* Copyright Daniel Ratcliffe, 2011-2016. 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 dan200.computercraft.api.filesystem.IWritableMount;
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import java.io.*;
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import java.util.List;
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public class FileMount implements IWritableMount
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{
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private static int MINIMUM_FILE_SIZE = 500;
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private class CountingOutputStream extends OutputStream
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{
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private OutputStream m_innerStream;
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private long m_ignoredBytesLeft;
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public CountingOutputStream( OutputStream innerStream, long bytesToIgnore )
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{
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m_innerStream = innerStream;
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m_ignoredBytesLeft = bytesToIgnore;
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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_innerStream.close();
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}
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@Override
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public void flush() throws IOException
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{
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m_innerStream.flush();
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}
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@Override
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public void write( byte[] b ) throws IOException
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{
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count( b.length );
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m_innerStream.write( b );
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}
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@Override
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public void write( byte[] b, int off, int len ) throws IOException
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{
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count( len );
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m_innerStream.write( b, off, len );
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}
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@Override
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public void write( int b ) throws IOException
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{
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count( 1 );
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m_innerStream.write( b );
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}
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private 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 )
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{
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throw new IOException( "Out of space" );
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}
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else
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{
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m_usedSpace += newBytes;
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}
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}
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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( String path ) throws IOException
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{
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if( !created() )
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{
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return path.length() == 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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return file.exists();
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}
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}
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@Override
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public boolean isDirectory( String path ) throws IOException
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{
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if( !created() )
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{
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return path.length() == 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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return file.exists() && file.isDirectory();
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}
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}
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@Override
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public void list( String path, 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.length() != 0 )
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{
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throw new IOException( "Not a directory" );
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}
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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() && file.isDirectory() )
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{
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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() )
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{
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contents.add( subPath );
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}
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}
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}
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else
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{
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throw new IOException( "Not a directory" );
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}
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}
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}
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@Override
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public long getSize( String path ) throws IOException
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{
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if( !created() )
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{
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if( path.length() == 0 )
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{
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return 0;
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}
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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() )
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{
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if( file.isDirectory() )
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{
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return 0;
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}
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else
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{
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return file.length();
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}
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}
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}
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throw new IOException( "No such file" );
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}
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@Override
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public InputStream openForRead( 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() )
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{
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return new FileInputStream( file );
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}
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}
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throw new IOException( "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( 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() )
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{
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throw new IOException( "File exists" );
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}
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}
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else
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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 IOException( "Out of space" );
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}
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boolean success = file.mkdirs();
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if( success )
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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 IOException( "Access denied" );
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}
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}
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}
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@Override
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public void delete( String path ) throws IOException
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{
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if( path.length() == 0 )
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{
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throw new IOException( "Access denied" );
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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() )
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{
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deleteRecursively( file );
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}
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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( int i=0; i<children.length; i++ )
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{
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deleteRecursively( new File( file, children[i] ) );
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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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@Override
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public OutputStream openForWrite( 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() )
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{
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throw new IOException( "Cannot write to directory" );
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}
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else
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{
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if( !file.exists() )
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{
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if( getRemainingSpace() < MINIMUM_FILE_SIZE )
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{
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throw new IOException( "Out of space" );
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}
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else
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{
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m_usedSpace += MINIMUM_FILE_SIZE;
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}
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}
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else
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{
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m_usedSpace -= Math.max( file.length(), MINIMUM_FILE_SIZE );
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m_usedSpace += MINIMUM_FILE_SIZE;
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}
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return new CountingOutputStream( new FileOutputStream( file, false ), MINIMUM_FILE_SIZE );
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}
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}
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@Override
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public OutputStream openForAppend( 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() )
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{
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throw new IOException( "No such file" );
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}
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else if( file.isDirectory() )
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{
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throw new IOException( "Cannot write to directory" );
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}
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else
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{
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return new CountingOutputStream( new FileOutputStream( file, true ), Math.max( MINIMUM_FILE_SIZE - file.length(), 0 ) );
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}
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}
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else
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{
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throw new IOException( "No such file" );
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}
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}
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@Override
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public long getRemainingSpace() throws IOException
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{
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return Math.max( m_capacity - m_usedSpace, 0 );
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}
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public 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 long measureUsedSpace( File file )
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{
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if( !file.exists() )
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{
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return 0;
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}
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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( int i=0; i<contents.length; ++i )
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{
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size += measureUsedSpace( new File( file, contents[i] ) );
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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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