Lintian::Output

Section: Debian Package Checker (3)
Updated: 2019-04-04
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NAME

Lintian::Output - Lintian messaging handling

SYNOPSIS

    # non-OO
    use Lintian::Output qw(:messages);

    $Lintian::Output::GLOBAL->verbosity_level(1);

    msg("Something interesting");
    v_msg("Something less interesting");
    debug_msg(3, "Something very specific");

    # OO
    use Lintian::Output;

    my $out = Lintian::Output->new;

    $out->verbosity_level(-1);
    $out->msg("Something interesting");
    $out->v_msg("Something less interesting");
    $out->debug_msg(3, "Something very specific");

DESCRIPTION

Lintian::Output is used for all interaction between lintian and the user. It is designed to be easily extensible via subclassing.

To simplify usage in the most common cases, many Lintian::Output methods can be used as class methods and will therefore automatically use the object $Lintian::Output::GLOBAL unless their first argument "isa('Lintian::Output')".

ACCESSORS

The following fields define the behaviours of Lintian::Output.

verbosity_level

Determine how verbose the output should be. ``0'' is the default value (tags and msg only), ``-1'' is quiet (tags only) and ``1'' is verbose (tags, msg and v_msg).

debug

If set to a positive integer, will enable all debug messages issued with a level lower or equal to its value.

color

Can take the values ``never'', ``always'', ``auto'' or ``html''.

Whether to colorize tags based on their severity. The default is ``never'', which never uses color. ``always'' will always use color, ``auto'' will use color only if the output is going to a terminal.

``html'' will output HTML <span> tags with a color style attribute (instead of ANSI color escape sequences).

stdout

I/O handle to use for output of messages and tags. Defaults to "\*STDOUT".

stderr

I/O handle to use for warnings. Defaults to "\*STDERR".

showdescription

Whether to show the description of a tag when printing it.

issuedtags

Hash containing the names of tags which have been issued.

tag_display_limit

Get/Set the number of times a tag is emitted per processable.

CLASS/INSTANCE METHODS

These methods can be used both with and without an object. If no object is given, they will fall back to the $Lintian::Output::GLOBAL object.

"msg(@args)"

Will output the strings given in @args, one per line, each line prefixed with 'N: '. Will do nothing if verbosity_level is less than 0.

"v_msg(@args)"

Will output the strings given in @args, one per line, each line prefixed with 'N: '. Will do nothing unless verbosity_level is greater than 0.

"debug_msg($level, @args)"

$level should be a positive integer.

Will output the strings given in @args, one per line, each line prefixed with 'N: '. Will do nothing unless debug is set to a positive integer >= $level.

"warning(@args)"

Will output the strings given in @args on stderr, one per line, each line prefixed with 'warning: '.

"perf_log(@args)"

Like ``v_msg'', except output is possibly sent to a dedicated log file.

Will output the strings given in @args, one per line. The lines will not be prefixed. Will do nothing unless perf_debug is set to a positive integer.

"delimiter()"

Gives back a string that is usable for separating messages in the output. Note: This does not print anything, it just gives back the string, use with one of the methods above, e.g.

 v_msg('foo', delimiter(), 'bar');

"issued_tag($tag_name)"

Indicate that the named tag has been issued. Returns a boolean value indicating whether the tag had previously been issued by the object.

"string($lead, @args)"

TODO: Is this part of the public interface?

INSTANCE METHODS FOR CONTEXT-AWARE OUTPUT

The following methods are designed to be called at specific points during program execution and require very specific arguments. They can only be called as instance methods.

"print_tag($pkg_info, $tag_info, $extra, $override)": Print a tag. The first two arguments are hash reference with the information about the package and the tag, $extra is the extra information for the tag (if any) as an array reference, and $override is either undef if the tag is not overridden or the override for this tag. Called from Lintian::Tags::tag().
"print_start_pkg($pkg_info)": Called before lintian starts to handle each package. The version in Lintian::Output uses v_msg() for output. Called from Tags::select_pkg().
"print_start_pkg($pkg_info)": Called after lintian is finished with a package. The version in Lintian::Output does nothing. Called from Lintian::Tags::file_start() and Lintian::Tags::file_end().

INSTANCE METHODS FOR SUBCLASSING

The following methods are only intended for subclassing and are only available as instance methods. The methods mentioned in ``CLASS/INSTANCE METHODS'' usually only check whether they should do anything at all (according to the values of verbosity_level and debug) and then call one of the following methods to do the actual printing. Almost all of them finally call _print() to do that. This convoluted scheme is necessary to be able to use the methods above as class methods and still make the behaviour overridable in subclasses.

"_message(@args)"

Called by msg(), v_msg(), and debug_msg() to print the message.

"_warning(@args)"

Called by warning() to print the warning.

"_print($stream, $lead, @args)"

Called by _message(), _warning(), and print_tag() to do the actual printing.

If you override these three methods, you can change the calling convention for this method to pretty much whatever you want.

The version in Lintian::Output prints the strings in @args, one per line, each line preceded by $lead to the I/O handle given in $stream.

"_delimiter()"

Called by delimiter().

"_do_color()"

Called by print_tag() to determine whether to produce colored output.

"_quote_print($string)"

Called to quote a string. By default it will replace all non-printables with ``?''. Sub-classes can override it if they allow non-ascii printables etc.

CLASS METHODS

"_global_or_object(@args)": If $args[0] is an object which satisfies "isa('Lintian::Output')" returns @args, otherwise returns "($Lintian::Output::GLOBAL, @_)".

EXPORTS

Lintian::Output exports nothing by default, but the following export tags are available:

:messages: Exports all the methods in ``CLASS/INSTANCE METHODS''
:util: Exports all the methods in ``CLASS METHODS''

AUTHOR

Originally written by Frank Lichtenheld <djpig@debian.org> for Lintian.