/ 
ClearCase-Argv-0.22
River stage one • 2 direct dependents • 3 total dependents
/ ClearCase::Argv

NAME

ClearCase::Argv - ClearCase-specific subclass of Argv

SYNOPSIS

    # OO interface
    use ClearCase::Argv;
    ClearCase::Argv->dbglevel(1);
    # Note how the command, flags, and arguments are separated ...
    my $describe = ClearCase::Argv->new('desc', [qw(-fmt %c)], ".");
    # Run the basic "ct describe" command.
    $describe->system;
    # Run it with with stderr turned off.
    $describe->stderr(0)->system;
    # Run it without the flags.
    $describe->system(-);
    # Create label type iff it doesn't exist
    ClearCase::Argv->new(qw(mklbtype -nc XX))
	    if ClearCase::Argv->new(qw(lstype lbtype:XX))->stderr(0)->qx;

    # functional interface
    use ClearCase::Argv qw(ctsystem ctexec ctqx);
    ctsystem('pwv');
    my @lsco = ctqx(qw(lsco -avobs -s));
    # Similar to OO example: create label type iff it doesn't exist
    ctsystem(qw(mklbtype XX)) if !ctqx({stderr=>0}, "lstype lbtype:XX");

There are more examples in the ./examples subdir that comes with this module. Also, the test script is designed as a demo and benchmark; it's probably your best source for cut-and-paste code.

DESCRIPTION

This is a subclass of Argv for use with ClearCase. It basically overrides the prog() method to recognize the fact that ClearCase commands have two words, e.g. "cleartool checkout".

It also provides a special method 'ipc_cleartool' which, as the name implies, enables use of the IPC::ClearTool module such that subsequent cleartool commands are sent to a coprocess.

ClearCase::Argv is otherwise identical to its base class, so see "perldoc Argv" for substantial further documentation.

IPC::ClearTool INTERFACE

The 'ipc_cleartool' method creates an IPC::ClearTool object and sends subsequent commands to it. This method is highly context-sensitive:

  • When called with no arguments and a non-void context, it returns the underlying ClearTool object (in case you want to use it directly).

  • When called with a non-zero argument it creates a ClearTool object; if this fails for any reason a warning is printed and execution continues in 'normal mode'. The warning may be suppressed or turned to a fatal error by specifying different true values; see examples below.

  • When called with an argument of 0, it shuts down any existing ClearTool object; any further executions would revert to 'normal mode'.

Examples

# use IPC::ClearTool if available, else continue silently
ClearCase::Argv->ipc_cleartool(1);
# use IPC::ClearTool if available, else print warning and continue
ClearCase::Argv->ipc_cleartool(2);
# same as above since default == 2
ClearCase::Argv->ipc_cleartool;
# use IPC::ClearTool, die if not available
ClearCase::Argv->ipc_cleartool(3);
# shut down the IPC::ClearTool coprocess
ClearCase::Argv->ipc_cleartool(0);
# Use the IPC::ClearTool object directly
ClearCase::Argv->ipc_cleartool->cmd('pwv');

Typically ipc_cleartool will be used as a class method to specify a place for all cleartool commands to be sent. However, it may also be invoked on an object to associate just that instance with a coprocess.

FUNCTIONAL INTERFACE

For those who don't like OO style, or who want to convert existing scripts with the least effort, the execution methods are made available as traditional functions. Examples:

use ClearCase::Argv qw(ctsystem ctexec ctqx);
my $cwv = ctqx(pwv -s);
ctsystem('mklbtype', ['-global'], 'FOO') && exit $?>>8;
my @vobs = ctqx({autochomp=>1}, 'lsvob -s');

If you prefer you can override the "real" Perl builtins. This is easier for converting an existing script which makes heavy use of system(), exec(), or qx():

use ClearCase::Argv qw(system exec qv);
my $cwv = qv(cleartool pwv -s);
system('cleartool', 'mklbtype', ['-global'], 'FOO') && exit $?>>8;
my @vobs = qv({autochomp=>1}, 'lsvob -s');

Note that when using an overridden system() et al you must still specify 'cleartool' as the program, whereas ctsystem() and friends handle that.

CAREFUL PROGRAMMERS WANTED

If you're the kind of programmer who tends to execute whole strings such as system("cleartool pwv -s") or who uses backquotes in a void context, this module won't help you much. These are bad habits regardless of whether you use ClearCase::Argv and you should strive to overcome them.

STICKINESS

A subtlety: when an execution attribute is set in a void context, it's "sticky", meaning that it's set until explicitly reset. But in a non-void context the new value is temporary or "non-sticky"; it's pushed on a stack and popped off after being read once. This applies to both class and instance uses. It's done this way to allow the following locutions:

ClearCase::Argv->stdout(0);	# turn off stdout for all objects
$obj->stdout(0);		# turn off stdout for this object, forever
$obj->stdout(0)->system;	# suppress stdout, this time only

This allows you to set up an object with various sticky attributes and keep it around, executing it at will and overriding other attrs temporarily. In the example below, note that another way of setting sticky attrs is shown:

my $obj = ClearCase::Argv->new({autofail=>1, autochomp=>1});
my $view = $obj->argv('pwv -s')->qx;
my $exists = $obj->argv('lstype', 'brtype:FOO')->autofail(0)->qx;

Here we keep an object with attrs 'autochomp' and 'autofail' (autofail means to exit on any failure) around and use it to exec whichever commands we want. While checking to see if a type exists, we suppress autofail temporarily. On the next use the object will have both attributes again.

BUGS

I suspect there are still some special quoting situations unaccounted for in the quote method. This will need to be refined over time. Bug reports or patches gratefully accepted.

PORTABILITY

ClearCase::Argv should work on all ClearCase platforms. It's primarily tested on Solaris 7 and NT 4.0, with CC 3.2.1 and 4.0, using Perl5.004 and 5.005. The CAL stuff doesn't work with CC <3.2.1.

FILES

The module is a subclass of Argv and thus requires it to be installed. If running in ipc mode it will also need IPC::ClearTool.

SEE ALSO

perl(1), Argv, IPC::ClearTool, IPC::ChildSafe

AUTHOR

David Boyce <dsb@world.std.com>

COPYRIGHT

Copyright (c) 1999,19100 David Boyce. All rights reserved. This Perl program is free software; you may redistribute it and/or modify it under the same terms as Perl itself.