Ubuntu Manpage: transfer::copy - Data transfer foundation

NAME

       transfer::copy - Data transfer foundation

SYNOPSIS

       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

________________________________________________________________________________________________________________

DESCRIPTION

       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.

API

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

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

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

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

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

transfer::copy::doChan channel outchannel optvar
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.

transfer::copy::doString string outchannel optvar
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.

transfer::copy::options outchannel optionlist optvar
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:

-blocksize int
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.

-command commandprefix
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.

-progress commandprefix
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.

-size int
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.

-encoding encodingname

-eofchar eofspec

-translation transspec
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.

BUGS, IDEAS, FEEDBACK

       This  document,  and  the package it describes, will undoubtedly contain bugs and other problems.  Please
       report such in the category  transfer  of  the  Tcllib  Trackers  [http://core.tcl.tk/tcllib/reportlist].
       Please also report any ideas for enhancements you may have for either package and/or documentation.

       When proposing code changes, please provide unified diffs, i.e the output of diff -u.

       Note  further  that  attachments  are strongly preferred over inlined patches. Attachments can be made by
       going to the Edit form of the ticket immediately after its creation, and then using the left-most  button
       in the secondary navigation bar.

KEYWORDS

       channel, copy, transfer

COPYRIGHT

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