transfer::copy(n) Data transfer facilities transfer::copy(n) 







transfer::copy - Data transfer foundation








package require Tcl 8.4


package require transfer::copy ?0.2?


transfer::copy::do chan|string data
    outchannel ?options...?


transfer::copy::chan channel outchannel
    ?options...?


transfer::copy::string string outchannel
    ?options...?


transfer::copy::doChan channel outchannel
    optvar


transfer::copy::doString string outchannel
    optvar


transfer::copy::options outchannel optionlist
    optvar












This package provides a number of commands for the asynchronous of
    information contained in either a string or channel. The main point of this
    package is that the commands here provide a nicer callback API than the
    builtin command fcopy, making the use of these facilities simpler
    than the builtin.









  

  
This command transfers the information in data to the
      outchannel, according to the options. The type of the
      information in data is determined by the first argument.
    
The options available to this command are the same as are
        available to the command transfer::copy::options, and explained
        there.

  







  

  
The argument data contains the handle of a channel and the actual
      infomration to transfer is read from that channel.

  

  
The argument data contains a string and this is the information to
      be transfered.







  

  
This command is a shorter and more direct form for the command
      transfer::copy::do chan.

  

  
This command is a shorter and more direct form for the command
      transfer::copy::do string.

  

  
This command is an alternate form of transfer::copy::chan which
      reads its options out of the array variable named by optvar instead
      of from a variable length argument list.

  

  
This command is an alternate form of transfer::copy::string which
      reads its options out of the array variable named by optvar instead
      of from a variable length argument list.

  

  
This command is the option processor used by all the commands above which
      read their options from a variable length argument list. It first reads
      default settings from the channel handle outchannel, then processes
      the list of options in optionlist, at last stores the results in
      the array variable named by optvar. The contents of that variable
      are in a format which is directly understood by all the commands above
      which read their options out of an array variable.
    
The recognized options are:

  







  

  
This option specifies the size of the chunks to transfer in one operation.
      It is optional and defaults to the value of -buffersize as
      configured for the output channel.
    
If specified its value has to be an integer number greater
        than zero.

  

  

  
This option specifies the completion callback of the operation. This
      option has to be specified. An error will be thrown if it is not, or if
      the empty list was specified as argument to it.
    
Its value has to be a command prefix, i.e. a list whose first
        word is the command to execute, followed by words containing fixed
        arguments. When the callback is invoked one or two additional arguments
        are appended to the prefix. The first argument is the number of bytes
        which were transfered. The optional second argument is an error message
        and added if and only if an error occured during the the transfer.

  

  

  
This option specifies the progress callback of the operation. It is
      optional and defaults to the empty list. This last possibility signals
      that no feedback was asked for and disabled it.
    
Its value has to be a command prefix, see above,
        -command for a more detailed explanation. When the callback is
        invoked a single additional arguments is appended to the prefix. This
        argument is the number of bytes which were transfered so far.

  

  

  
This option specifies the number of bytes to read from the input data and
      transfer. It is optional and defaults to "Transfer everything".
      Its value has to be an integer number and any value less than zero has the
      same meaning, i.e. to transfer all available data. Any other value is the
      amount of bytes to transfer.
    
All transfer commands will throw error an when their user
        tries to transfer more data than is available in the input. This happens
        immediately, before the transfer is actually started, should the input
        be a string. Otherwise the, i.e. for a channel as input, the error is
        thrown the moment the underflow condition is actually detected.

  

  

  

  

  

  

  
These options are the same as are recognized by the builtin command
      fconfigure and provide the settings for the output channel which
      are to be active during the transfer, and only then. I.e. the settings of
      the output channel before the transfer are saved, and restored at the end
      of a transfer, regardless of its success or failure. None of these options
      are required, and they default to the settings of the output channel if
      not specified.












This document, and the package it describes, will undoubtedly
    contain bugs and other problems. Please report such in the category
    transfer of the Tcllib SF Trackers
    [http://sourceforge.net/tracker/?group_id=12883]. Please also report any
    ideas for enhancements you may have for either package and/or
  documentation.








channel, copy, transfer








Transfer module








Copyright (c) 2006-2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>








  

    0.2
    transfer