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NAME

File::Globstar::ListMatch - Match File Names Against List Of Patterns

SYNOPSIS

use File::Globstar::ListMatch;

# Parse from file.
$matcher = File::Globstar::ListMatch->new('.gitignore', 
                                          ignoreCase => 1,
                                          isExclude => 1);

# Parse from file handle.
$matcher = File::Globstar::ListMatch->new(STDIN, ignoreCase => 0);

# Parse list of patterns.  Comments and blank lines are not
# stripped!
$matcher = File::Globstar::ListMatch->new([
    'src/**/*.o',
    '.*',
    '!.gitignore'
], filename => 'exclude.txt');

# Parse string.
$patterns = <<EOF;
# Ignore all compiled object files.
src/**/*.o
# Ignore all hidden files.
'.*'
# But not this one.
'.gitignore'
EOF
$matcher = File::Globstar::ListMatch->new(\$pattern);

$filename = 'path/to/hello.o';
if ($matcher->match($filename)) {
    print "Ignore '$filename'.\n";
}

DESCRIPTION

Files containing list of files are very common as arguments to command-line options such as "--ignore", "--exclude" or "--include". A well-known example is the syntax used by git as described in https://git-scm.com/docs/gitignore.

This module implements the same functionality in Perl.

While the module will normally be used for matching against filenames, no file system operations are done. Only strings are compared. The reason for this is that it should be possible to match names of deleted files as well as existing files.

INPUT FILE FORMAT

Unless you pass a reference to an array of patterns as input, comments and blank lines are discarded.

Comments

Comments are lines that start with a hash-sign. You can escape hash-signs that are part of the pattern with a backslash: "\#".

Blank Lines

Blank lines are empty lines or lines consisting of whitespace only. Whitespace is a sequence of US-ASCII whitespace characters: horizontal tabs (ASCII 9), line feeds (ASCII 10), vertical tabs (ASCII 11), form feeds (ASCII 12), carriage returns (ASCII 13), and space (ASCII 32). Other characters with the Unicode property "WSpace=Y" are not considered whitespace.

Leading whitespace (see above) is not removed! Likewise, whitespace between the leading negation "!" and the pattern is not removed! On the other hand, in order to ignore a file named " " you have to backslash-escape the first space character ("\ "). Otherwise, the pattern will be interpreted as a blank line and ignored. This is consistent with the behavior of Git.

PATTERNS

Patterns undergo a little preprocessing:

A leading exclamation is stripped off

But the pattern is now negated. It produces a match for all files that do not match the pattern. A literal exclamation mark can be escaped with a backslash.

A leading slash is stripped off

But the pattern must match the entire significant "path" (actually string). For example "/foobar" matches for "/foobar" but not for "/sub/sub/foobar".

A trailing slash is stripped off

But the pattern can only match "directories". This is why the method match() below has an optional second argument that lets you specify, whether the string to be matched is considered a directory or not.

MATCHING ALGORITHM

The string (normally a filename) passed to the matcher is compared subsequently to all patterns. If none of the patterns match or if the last match was against a negated pattern, the overall result is false. Otherwise it is true.

If a patterrn contains a slash ("/"), the match is done against the full path name, otherwise just against the basename of the file with a leading "directory" part stripped off.

If a pattern starts with a leading slash, that slash is stripped off for the purpose of comparison but the string must match relative to the base "directory".

The semantics of a match are the same as for fnmatchstar() in File::Globstar. But keep in mind that a leading exclamation mark (for negation), a leading "directory" part, a leading slash, or a trailing slash may be stripped off according to the rules outline above.

METHODS

new INPUT[, %OPTIONS]

Creates a new File::Globstar::ListMatch object. INPUT can be:

FILE

FILE can be a filename, an open file handle, or a reference to an open file handle.

STRINGREF

STRINGREF is a reference to a string containing the patterns.

ARRAYREF

You can also pass a list of patterns as an array reference. Leading exclamation marks ("!") followed by possible whitespace for negating patterns are stripped off, but otherwise all patterns are taken as is, even blank ones and patterns starting with a hash-sign ("#").

The input source can be followed by optional named arguments passed as key-value pairs. Currently recogized:

ignoreCase => 0|1|undef

Controls, whether to ignore case, when matching. A true value will cause case to be ignored. The default value is false, so that matches are done in a case-sensitive manner. This is an appropriate setting for both case-sensitive and case-preserving file systems.

filename => FILENAME

Use FILENAME in messages for I/O errors.

match STRING[, IS_DIRECTORY]

Returns true if STRING matches. If you pass a true value for the optional argument IS_DIRECTORY, STRING is considered to be the name of a directory.

A leading slash in STRING is stripped off and is ignored.

A trailing slash is also ignored but STRING is then considered to be a directory name and IS_DIRECTORY is ignored.

When comparing against a pattern that contains a slash (except for a trailing slash), the full string is taken into account. Otherwise, only the part after the last (non-trailing) slash is taken into account.

Note that match() assumes that you are excluding or ignoring files. This exclude mode implies that certain negations do not make sense and are ignored. Thake this example:

/node_modules
!/node_modules/foobar

The second line gets ignored. In exclude mode it is assumed that you recurse a directory calling match() for every file you visit. If a file matches it is always ignored. And if it is a directory, it is not only ignored but the recursion also stops here.

The exact rule is: You cannot re-include a file by negating a pattern if one of the file's parent directories would be excluded.

This is the behavior of git, when evaluating ignore lists. If you want to avoid that behavior, see below for matchInclude().

On the other hand, the following is possible:

docs/_*
!docs/_posts

The only "parent directory" for the negation is docs and that is not excluded. This is different to this example:

docs/_*
!docs/_posts/recent

The "parent directories" are docs and docs/_posts and docs/_posts matches against docs/_*. The negation is therefore invalid and ignored.

matchExclude STRING[, IS_DIRECTORY]

This is an alias for match()

matchInclude STRING[, IS_DIRECTORY]

Does the same as match() but all negations are valid.

The metaphor for include mode is different from exclude mode that is assumed by match() resp. matchExclude(). In include mode you would interpret all patterns as globbing patterns. A positive, non-negated pattern would cause the matching files to be added to result list. A negated pattern will remove the matching files from the result list. The operation would happen recursively if a directory gets added or removed.

We take almost the same example as for match() above:

docs/_*
!docs/_posts/archive

Imagine line 1 would produce the following list:

  • docs/_views/

  • docs/_views/main.html

  • docs/_views/head/

  • docs/_views/head/meta.html

  • docs/_posts/new/

  • docs/_posts/new/post4321.html

  • docs/_posts/archive/

  • docs/_posts/archive/post1.html

  • docs/_posts/archive/post2.html

    Line 2 would then kickout the last three matches from the result list.

patterns

Returns the patterns as a list of compiled regular expressions. This is useful probably only for testing.

BUGS AND CAVEATS

The module interprets backslashes only for escaping. It does not assume any path separator semantics for them. This should normally not be a problem.

Git ignores all hidden files by default. If you want the same behavior for File::Globstar::ListMatch, put a ".*" in front of the patterns.

COPYRIGHT

Copyright (C) 2016-2018 Guido Flohr <guido.flohr@cantanea.com>, all rights reserved.

SEE ALSO

File::Globstar(3pm), File::Glob(3pm), glob(3), glob(7), fnmatch(3), glob(1), perl(1)