NAME¶
transfer::data::destination - Data destination
SYNOPSIS¶
package require
Tcl 8.4
package require
snit ?1.0?
package require
transfer::data::destination ?0.2?
transfer::data::destination objectName ?
options...?
objectName method ?
arg arg ...?
objectName destroy
objectName put chunk
objectName done
objectName valid msgvar
objectName receive channel done
DESCRIPTION¶
This package provides objects mainly describing the destination of a data
transfer. They are also able to initiate the reception of information from a
channel into the described destination.
API¶
- transfer::data::destination objectName
?options...?
- This command creates a new data destination object with an associated Tcl
command whose name is objectName. This object command is
explained in full detail in the sections Object command and
Object methods. The set of supported options is explained in
section Options.
The object command will be created under the current namespace if the
objectName is not fully qualified, and in the specified namespace
otherwise. The fully qualified name of the object command is returned as
the result of the command.
OBJECT COMMAND¶
All objects created by the
::transfer::data::destination command have the
following general form:
- objectName method ?arg arg ...?
- The method method and its arg'uments determine the exact
behavior of the command. See section Object methods for the
detailed specifications.
OBJECT METHODS¶
- objectName destroy
- This method destroys the object. Doing so while the object is busy with
the reception of information from a channel will cause errors later on,
when the reception completes and tries to access the now missing data
structures of the destroyed object.
- objectName put chunk
- The main receptor method. Saves the received chunk of data into the
configured destination. It has to be called for each piece of data
received.
- objectName done
- The secondary receptor method. Finalizes the receiver. It has to be called
when the receiving channel signals EOF. Afterward neither itself nor
method put can be called anymore.
- objectName valid msgvar
- This method checks the configuration of the object for validity. It
returns a boolean flag as result, whose value is True if the object
is valid, and False otherwise. In the latter case the variable
whose name is stored in msgvar is set to an error message
describing the problem found with the configuration. Otherwise this
variable is not touched.
- objectName receive channel done
- This method initiates the reception of data from the specified
channel. The received data will be stored into the configured
destination, via calls to the methods put and done. When the
reception completes the command prefix done is invoked, with the
number of received characters appended to it as the sole additional
argument.
OPTIONS¶
All data destinations support the options listed below. It should be noted that
all are semi-exclusive, each specifying a different type of destination and
associated information. If these options are specified more than once then the
last option specified is used to actually configure the object.
- -channel handle
- This option specifies that the destination of the data is a channel, and
its associated argument is the handle of the channel to write the received
data to.
- -file path
- This option specifies that the destination of the data is a file, and its
associated argument is the path of the file to write the received data
to.
- -variable varname
- This option specifies that the destination of the data is a variable, and
its associated argument contains the name of the variable to write the
received data to. The variable is assumed to be global or namespaced,
anchored at the global namespace.
- -progress command
- This option, if specified, defines a command to be invoked for each chunk
of bytes received, allowing the user to monitor the progress of the
reception of the data. The callback is always invoked with one additional
argument, the number of bytes received so far.
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, data destination, transfer
CATEGORY¶
Transfer module
COPYRIGHT¶
Copyright (c) 2006-2009 Andreas Kupries <andreas_kupries@users.sourceforge.net>