io.milton.zsync

Class UploadReader

java.lang.Object

io.milton.zsync.UploadReader

public class UploadReader
extends Object

An object that performs the server side operations needed to assemble the file from a ZSync PUT.

These operations consist of copying byte ranges into the new file. The moveBlocks(byte[], java.util.List<io.milton.zsync.RelocateRange>, int, byte[]) method copies ranges from the previous file according to a list of RelocateRanges, while the sendRanges(byte[], java.util.List<io.milton.http.Range>, byte[]) method copies the new data received in the upload. Both of these methods are overloaded with versions that accept File rather than byte[] arguments for dealing with large files that should not be loaded into memory all at once.

To assemble the file from a ZSync upload, the server should construct an UploadReader, passing to the constructor the file to be updated and an InputStream containing the upload data. It should then invoke the assemble() method, which will return a temporary file that was created.

Author:

Nick

Constructor Summary

Constructors

Constructor and Description
UploadReader(File serverFile, InputStream uploadIn) Constructor that parses the InputStream into an Upload object and initializes a temporary file that will contain the assembled upload

Method Summary

Modifier and Type	Method and Description
File	assemble() Invokes the methods to put together the uploaded file.
String	getChecksum() Returns the expected SHA1 checksum String received in the upload
static void	moveBlocks(byte[] in, List<RelocateRange> rlist, int blockSize, byte[] out) Copies blocks of data from the in array to the out array.
static void	moveBlocks(File inFile, Enumeration<RelocateRange> relocRanges, int blocksize, File outFile) Copies blocks of data from the input File to the output File.
static void	sendRanges(byte[] in, List<Range> ranges, byte[] out) Copies bytes from the in array into Ranges of the out array.
static void	sendRanges(Enumeration<ByteRange> byteRanges, File outFile) Inserts the data from each DataRange into the output File, at the appropriate offset

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

UploadReader

public UploadReader(File serverFile,
                    InputStream uploadIn)
             throws IOException

Constructor that parses the InputStream into an Upload object and initializes a temporary file that will contain the assembled upload

Parameters:

serverFile - The server file to be updated

uploadIn - A stream containing the ZSync PUT data

Throws:

IOException

Method Detail

moveBlocks

public static void moveBlocks(byte[] in,
                              List<RelocateRange> rlist,
                              int blockSize,
                              byte[] out)

Copies blocks of data from the in array to the out array.

Parameters:

in - The byte array containing the server's file being replaced

rlist - The List of RelocateRanges received from the upload

blockSize - The block size used in rlist

out - The byte array of the file being assembled

moveBlocks

public static void moveBlocks(File inFile,
                              Enumeration<RelocateRange> relocRanges,
                              int blocksize,
                              File outFile)
                       throws IOException

Copies blocks of data from the input File to the output File. For each RelocateRange A-B/C in relocRanges, the block starting at A and ending at B-1 is copied from inFile and written to byte C of outFile.

Parameters:

inFile - The server's File being replaced

relocRanges - The Enumeration of RelocateRanges parsed from the Upload's relocStream

blocksize - The block size used in relocRanges

outFile - The File being assembled

Throws:

IOException

sendRanges

public static void sendRanges(byte[] in,
                              List<Range> ranges,
                              byte[] out)

Copies bytes from the in array into Ranges of the out array. The in array is expected to contain the queued bytes in the same order as the ranges List.

Parameters:

in - An array containing the queued bytes corresponding to the ranges List

ranges - The List of target Ranges

out - The byte array for the file being assembled

sendRanges

public static void sendRanges(Enumeration<ByteRange> byteRanges,
                              File outFile)
                       throws IOException

Inserts the data from each DataRange into the output File, at the appropriate offset

Parameters:

byteRanges - The Enumeration of Range/InputStream pairs parsed from the Upload's dataStream

outFile - The output File being assembled

Throws:

IOException

assemble

public File assemble()
              throws IOException

Invokes the methods to put together the uploaded file.

Returns:

The assembled File

Throws:

IOException

getChecksum

public String getChecksum()

Returns the expected SHA1 checksum String received in the upload

Returns:

A SHA1 checksum