grep-changelogって何?

grep-changelogコマンドが、どのようにテキスト整形しているか気になるところです。

おそらくスクリプトなので、シンボリックリンクを辿っていきます。

takk@deb9:~$ which grep-changelog
/usr/bin/grep-changelog
takk@deb9:~$ 
takk@deb9:~$ !! | xargs file
which grep-changelog | xargs file
/usr/bin/grep-changelog: symbolic link to /etc/alternatives/grep-changelog
takk@deb9:~$ 
takk@deb9:~$ ^file^readlink -e^
which grep-changelog | xargs readlink -e
/usr/bin/grep-changelog.emacs24
takk@deb9:~$ 
takk@deb9:~$ !! | xargs file
which grep-changelog | xargs readlink -e | xargs file
/usr/bin/grep-changelog.emacs24: Perl script text executable
takk@deb9:~$ 

なんとPerlでしたね。

takk@deb9:~$ ^file^wc -l^
which grep-changelog | xargs readlink -e | xargs wc -l
265 /usr/bin/grep-changelog.emacs24
takk@deb9:~$ 

265行。
行数も少ないので全文みてみます。

takk@deb9:~$ ^wc -l^cat -n^
which grep-changelog | xargs readlink -e | xargs cat -n
     1	#! /usr/bin/perl
     2	
     3	# Copyright (C) 1999-2015 Free Software Foundation, Inc.
     4	#
     5	# This file is part of GNU Emacs.
     6	
     7	# GNU Emacs is free software: you can redistribute it and/or modify
     8	# it under the terms of the GNU General Public License as published by
     9	# the Free Software Foundation, either version 3 of the License, or
    10	# (at your option) any later version.
    11	
    12	# GNU Emacs is distributed in the hope that it will be useful,
    13	# but WITHOUT ANY WARRANTY; without even the implied warranty of
    14	# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    15	# GNU General Public License for more details.
    16	
    17	# You should have received a copy of the GNU General Public License
    18	# along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
    19	
    20	
    21	# Extract entries from ChangeLogs matching specified criteria.
    22	# Optionally format the resulting output to a form suitable for RCS
    23	# logs, like they are used in Emacs, for example.  In this format,
    24	# author lines, leading spaces, and file names are removed.
    25	
    26	require 5;
    27	use strict;
    28	
    29	# Parse command line options.
    30	
    31	use vars qw($author $regexp $exclude $from_date $to_date
    32	            $rcs_log $with_date $version $help $reverse
    33	            @entries);
    34	
    35	use Getopt::Long;
    36	
    37	my $result;
    38	
    39	if (@ARGV == 0) {
    40	
    41	    # No arguments cannot possibly mean "show everything"!!
    42	    $result = 0;
    43	
    44	} else {
    45	
    46	    $result = GetOptions ("author=s" => \$author,
    47	                          "text=s"  => \$regexp,
    48	                          "exclude=s"  => \$exclude,
    49	                          "from-date=s" => \$from_date,
    50	                          "to-date=s" => \$to_date,
    51	                          "rcs-log" => \$rcs_log,
    52	                          "with-date" => \$with_date,
    53	                          "reverse!" => \$reverse,
    54	                          "version" => \$version,
    55	                          "help"    => \$help);
    56	
    57	    # If date options are specified, check that they have the format
    58	    # YYYY-MM-DD.
    59	
    60	    $result = 0 if $from_date && $from_date !~ /^\d\d\d\d-\d\d-\d\d$/;
    61	    $result = 0 if $to_date && $to_date !~ /^\d\d\d\d-\d\d-\d\d$/;
    62	}
    63	
    64	# Print usage information and exit when necessary.
    65	
    66	if ($result == 0 || $help) {
    67	    print <<USAGE;
    68	
    69	Usage: $0 [options] [CHANGELOG...]
    70	
    71	Print entries in ChangeLogs matching various criteria.
    72	Valid options are:
    73	
    74	  --author=AUTHOR         Match entries whose author line matches
    75				  regular expression AUTHOR
    76	  --text=TEXT             Match entries whose text matches regular
    77				  expression TEXT
    78	  --exclude=TEXT	  Exclude entries matching TEXT
    79	  --from-date=YYYY-MM-DD  Match entries not older than given date
    80	  --to-date=YYYY-MM-DD    Match entries not younger than given date
    81	  --rcs-log		  Format output suitable for RCS log entries
    82	  --with-date		  Print short date line in RCS log
    83	  --reverse               Show entries in reverse (chronological) order
    84	  --version		  Print version info
    85	  --help		  Print this help
    86	
    87	If no CHANGELOG is specified scan the files "ChangeLog" and
    88	"ChangeLog.N+" in the current directory.  Old-style dates in ChangeLogs
    89	are not recognized.
    90	USAGE
    91	    exit !$help;
    92	}
    93	
    94	# Print version info and exit if `--version' was specified.
    95	
    96	if ($version) {
    97	    print "0.3\n";
    98	    exit 0;
    99	}
   100	
   101	
   102	# Value is non-zero if HEADER matches according to command line
   103	# options specified, i.e. it matches $author, and its date is in
   104	# the range $from_date <= date <= $to_date.
   105	
   106	sub header_match_p {
   107	    my $header = shift;
   108	
   109	    return 0 unless $header;
   110	
   111	    # No match if AUTHOR-regexp specified and doesn't match.
   112	    return 0 if $author && $header !~ /$author/;
   113	
   114	    # Check that the date of the entry matches if date options
   115	    # `--from-date' and/or `--to-date' were specified .  Old-style
   116	    # dates in ChangeLogs are not recognized, and never match.
   117	    if ($from_date || $to_date) {
   118		if ($header =~ /^(\d\d\d\d-\d\d-\d\d)/) {
   119		    my $date = $1;
   120		    return 0 if $from_date && $date lt $from_date;
   121		    return 0 if $to_date && $date gt $to_date;
   122		} else {
   123		    # Don't bother recognizing old-style dates.
   124		    return 0;
   125		}
   126	    }
   127	
   128	    return 1;
   129	}
   130	
   131	
   132	# Value is non-zero if ENTRY matches the criteria specified on the
   133	# command line, i.e. it matches $regexp, and it doesn't match
   134	# $exclude.
   135	
   136	sub entry_match_p {
   137	    my $entry = shift;
   138	
   139	    return 0 unless $entry;
   140	
   141	    if ($regexp) {
   142		return 1 if ($entry =~ /$regexp/
   143			     && (!$exclude || $entry !~ $exclude));
   144	    } else {
   145		return 1 if !$exclude || $entry !~ $exclude;
   146	    }
   147	
   148	    return 0;
   149	}
   150	
   151	
   152	# Print HEADER and/or ENTRY in a format suitable for what was
   153	# specified on the command line.  If $rcs_log is specified, author
   154	# lines are not printed, and leading spaces and file names are removed
   155	# from ChangeLog entries.
   156	
   157	sub print_log {
   158	    my ($header, $entry) = @_;
   159	    my $output = '';
   160	
   161	    if ($rcs_log) {
   162		# Remove leading whitespace from entry.
   163		$entry =~ s/^\s+//mg;
   164		# Remove file name parts.
   165		$entry =~ s/^\*.*\(/(/mg;
   166		# Remove file name parts, 2.
   167		$entry =~ s/^\*.*://mg;
   168	        if ($with_date) {
   169		    $header =~ /(\d\d\d\d-\d\d-\d\d)/;
   170		    $output = "!changelog-date $1\n";
   171		}
   172		$output .= $entry;
   173	    } else {
   174		$output .= $header . $entry;
   175	    }
   176	
   177	    if ($reverse) {
   178	        push @entries, $output;
   179	    } else {
   180	        print $output;
   181	    }
   182	}
   183	
   184	# Scan LOG for matching entries, and print them to standard output.
   185	
   186	sub parse_changelog {
   187	    my $log = shift;
   188	    my $entry = undef;
   189	    my $header = undef;
   190	
   191	    @entries = () if $reverse;
   192	
   193	    # Open the ChangeLog.
   194	    open (IN, "< $log") || die "Cannot open $log: $!";
   195	
   196	    while (defined(my $line = <IN>)) {
   197		if ($line =~ /^\S/) {
   198		    # Line is an author-line.  Print previous entry if
   199		    # it matches.
   200		    print_log ($header, $entry)
   201			if header_match_p ($header) && entry_match_p ($entry);
   202	
   203		    $entry = "";
   204	  	    $header = $line;
   205	
   206		    # Add empty lines below the header.
   207		    while (defined($line = <IN>) && $line =~ /^\s*$/) {
   208		        $header = "$header$line";
   209		    }
   210	        }
   211	
   212	        last unless defined $line;
   213	
   214		if ($line =~ /^\s*\*/) {
   215		    # LINE is the first line of a ChangeLog entry.  Print
   216		    # previous entry if it matches.
   217		    print_log ($header, $entry)
   218			if header_match_p ($header) && entry_match_p ($entry);
   219		    $entry = $line;
   220		} else {
   221		    # Add LINE to the current entry.
   222		    $entry = "$entry$line";
   223		}
   224	    }
   225	
   226	    # Print last entry if it matches.
   227	    print_log ($header, $entry)
   228		if header_match_p ($header) && entry_match_p ($entry);
   229	
   230	    close IN;
   231	
   232	    if ($reverse) {
   233	        for (my $entry = @entries; $entry; $entry--) {
   234	            print $entries[$entry-1];
   235	        }
   236	    }
   237	}
   238	
   239	
   240	# Main program.  Process ChangeLogs.
   241	
   242	# If files were specified on the command line, parse those files in the
   243	# order supplied by the user; otherwise parse default files ChangeLog and
   244	# ChangeLog.NNN according to $reverse.
   245	unless (@ARGV > 0) {
   246	    @ARGV = ("ChangeLog");
   247	
   248	    push @ARGV,
   249	      map {"ChangeLog.$_"}
   250	        sort {$b <=> $a}
   251	          map {/\.(\d+)$/; $1}
   252	            do {
   253	                opendir D, '.';
   254	                grep /^ChangeLog\.\d+$/, readdir D;
   255	            };
   256	
   257	    @ARGV = reverse @ARGV if $reverse;
   258	}
   259	
   260	while (defined (my $log = shift @ARGV)) {
   261	    parse_changelog ($log) if -f $log;
   262	}
   263	
   264	
   265	# grep-changelog ends here.
takk@deb9:~$ 

メイン処理は、240行目からなので、ここから見ていこうと思いましたが、
いきなり分かりません。

   246	    @ARGV = ("ChangeLog");

これって配列初期化しているだけなのでしょうけど、なぜChangeLogって文字列で初期化しているんでしょう。
ふむふむ、面白くなってきました。

つづく

Leave a Reply

Your email address will not be published. Required fields are marked *

CAPTCHA