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