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.
KEYWORDS¶
channel, copy, transfer
CATEGORY¶
Transfer module
COPYRIGHT¶
Copyright (c) 2006-2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>