stow/Stow.pm
2011-11-09 23:16:08 +00:00

533 lines
16 KiB
Perl
Executable file

#!/usr/bin/perl
# GNU Stow - manage the installation of multiple software packages
# Copyright (C) 1993, 1994, 1995, 1996 by Bob Glickstein
# Copyright (C) 2000,2001 Guillaume Morin
# Copyright (C) 2005 Adam Spiers
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#
# $Id$
# $Source$
# $Date$
# $Author$
#####################################################################
# Wed Nov 23 2005 Adam Spiers <stow@adamspiers.org>
# Hacked to ignore anything listed in ~/.cvsignore
#
# Thu Dec 29 2005 Adam Spiers <stow@adamspiers.org>
# Hacked into a Perl module
#####################################################################
package Stow;
use strict;
use warnings;
use File::Spec;
use FindBin qw($RealBin $RealScript);
use Getopt::Long;
use POSIX;
use lib "$RealBin/../lib/perl5";
use Sh 'glob_to_re';
my $ignore_file = File::Spec->join($ENV{HOME}, ".cvsignore");
my $ignore_re = get_ignore_re_from_file($ignore_file);
require 5.005;
our %opts;
sub SetOptions {
%opts = @_;
}
sub Init {
# Changing dirs helps a lot when soft links are used
my $current_dir = &getcwd;
if ($opts{stow}) {
chdir($opts{stow}) || die "Cannot chdir to target tree $opts{stow} ($!)\n";
}
# This prevents problems if $opts{target} was supplied as a relative path
$opts{stow} = &getcwd;
chdir($current_dir) || die "Your directory does not seem to exist anymore ($!)\n";
$opts{target} = Stow::parent($opts{stow}) unless $opts{target};
chdir($opts{target}) || die "Cannot chdir to target tree $opts{target} ($!)\n";
$opts{target} = &getcwd;
}
sub CheckCollections {
foreach my $package (@_) {
$package =~ s,/+$,,; # delete trailing slashes
if ($package =~ m,/,) {
die "$RealScript: slashes not permitted in package names ($package)\n";
}
}
}
sub CommonParent {
my($dir1, $dir2) = @_;
my($result, $x);
my(@d1) = split(/\/+/, $dir1);
my(@d2) = split(/\/+/, $dir2);
while (@d1 && @d2 && (($x = shift(@d1)) eq shift(@d2))) {
$result .= "$x/";
}
chop($result);
return $result;
}
# Find the relative patch between
# two paths given as arguments.
sub RelativePath {
my($a, $b) = @_;
my($c) = &CommonParent($a, $b);
my(@a) = split(/\/+/, $a);
my(@b) = split(/\/+/, $b);
my(@c) = split(/\/+/, $c);
# if $c == "/something", scalar(@c) >= 2
# but if $c == "/", scalar(@c) == 0
# but we want 1
my $length = scalar(@c) ? scalar(@c) : 1;
splice(@a, 0, $length);
splice(@b, 0, $length);
unshift(@b, (('..') x (@a + 0)));
&JoinPaths(@b);
}
# Concatenates the paths given as arguments, removing double slashes.
sub JoinPaths {
# The code that was previously here from 1.3.3 was strangely complex
# for no obvious reason. I (Adam) wrote a test suite and found this
# drop-in replacement to behave identically.
# my $result = join '/', @_;
# $result =~ s!//!/!g;
# return $result;
# So does this, but is also portable.
return File::Spec->join(@_);
}
# This removes stow-controlled symlinks from $targetdir for the
# packages in the %$PkgsToUnstow hash, and is called recursively to
# process subdirectories.
sub Unstow {
my($targetdir, $stow, $PkgsToUnstow) = @_;
# Note $targetdir is relative to the top of the target hierarchy,
# i.e. $opts{target}.
#
# $stow is the stow directory (the one containing the source
# packages), and is always relative to $targetdir. So as we
# recursively descend into $opts{target}, $stow gets longer because
# we have to move up out of that hierarchy and back into the stow
# directory.
# Does this whole subtree only contain symlinks to a *single*
# package collection *other* than one we are removing? We assume so
# and scan the tree recursively until we find out otherwise. We
# have to track this because if a subtree is found to be pure, we
# can fold it into a single symlink.
my $pure = 1;
# If the directory is pure, we need to know which single other
# package collection the contained symlinks point to, so we know how
# to do our tree folding.
my $othercollection = '';
# We assume $targetdir is empty until we find something.
my $empty = 1;
my $targetdirPath = &JoinPaths($opts{target}, $targetdir);
return (0, '') if $targetdirPath eq $opts{stow};
return (0, '') if -e &JoinPaths($targetdirPath, '.stow');
warn "Unstowing in $targetdirPath\n"
if $opts{verbose} > 1;
if (!opendir(DIR, $targetdirPath)) {
warn "Warning: $RealScript: Cannot read directory \"$targetdirPath\" ($!). Stow might leave some links. If you think, it does. Rerun Stow with appropriate rights.\n";
}
my @contents = readdir(DIR);
closedir(DIR);
my @puresubdirs;
foreach my $content (@contents) {
next if ($content eq '.') || ($content eq '..');
$empty = 0;
my $contentPath = &JoinPaths($targetdirPath, $content);
if (-l $contentPath) {
# We found a link; now let's see if we should remove it.
my $linktarget = readlink $contentPath;
$linktarget or die "$RealScript: Cannot read link $contentPath ($!)\n";
# Does the link point to somewhere within the stow directory?
my $stowmember = &FindStowMember(
$targetdirPath,
$linktarget,
);
if ($stowmember) {
# Yes it does, but does it point within one of the package
# collections we are unstowing?
my @stowmember = split(/\/+/, $stowmember);
my $collection = shift(@stowmember);
if ($PkgsToUnstow->{$collection}) {
# Yep, so get rid of it.
&DoUnlink($contentPath);
} else {
# No, it points to another package collection. Is there
# still a chance this directory is pure and can be folded?
if ($pure) {
# Yes, so keep track of whether symlinks in the directory
# point to more than one collection.
if ($othercollection) {
# More than one collection means impure => no folding possible.
$pure = 0 if $collection ne $othercollection;
} else {
# This is the first reference to another collection
# we've seen, so remember it for future comparison with
# other symlink targets.
$othercollection = $collection;
}
}
}
} else {
# Link points outside the stow directory, therefore is not
# managed by stow and cannot be touched. So tree folding will
# not be possible.
$pure = 0;
}
}
elsif (-d $contentPath) {
# recurse
my ($subpure, $subother) = &Unstow(
&JoinPaths($targetdir, $content),
&JoinPaths('..', $stow),
$PkgsToUnstow,
);
if ($subpure) {
push @puresubdirs, "$content/$subother";
}
else {
# Subtree is impure therefore this directory is impure.
$pure = 0;
}
if ($pure && $subpure) {
if ($othercollection) {
# We already found a single other package collection
# somewhere in this subtree but outside $contentPath.
if ($subother and $othercollection ne $subother) {
# Two collections pointed to from within one subtree,
# so no tree folding will be possible.
$pure = 0;
}
} elsif ($subother) {
# This is the first other package collection we've found;
# remember it as before for future comparison with other
# symlinks.
$othercollection = $subother;
}
}
} else {
# Current directory contains something other than a symlink or a
# directory, therefore folding is not going to be possible.
$pure = 0;
}
}
# This directory was an initially empty directory therefore
# we do not remove it.
$pure = 0 if $empty;
if ((!$pure || !$targetdir) && @puresubdirs) {
&CoalesceTrees($targetdir, $stow, @puresubdirs);
}
return ($pure, $othercollection);
}
# This is the tree folding which the stow manual refers to.
sub CoalesceTrees {
my($parent, $stow, @trees) = @_;
foreach my $x (@trees) {
my ($tree, $collection) = ($x =~ /^(.*)\/(.*)/);
&EmptyTree(&JoinPaths($opts{target}, $parent, $tree));
&DoRmdir(&JoinPaths($opts{target}, $parent, $tree));
if ($collection) {
&DoLink(&JoinPaths($stow, $collection, $parent, $tree),
&JoinPaths($opts{target}, $parent, $tree));
}
}
}
sub EmptyTree {
my($dir) = @_;
opendir(DIR, $dir)
|| die "$RealScript: Cannot read directory \"$dir\" ($!)\n";
my @contents = readdir(DIR);
closedir(DIR);
foreach my $content (@contents) {
next if (($content eq '.') || ($content eq '..'));
if (-l &JoinPaths($dir, $content)) {
&DoUnlink(&JoinPaths($dir, $content));
} elsif (-d &JoinPaths($dir, $content)) {
&EmptyTree(&JoinPaths($dir, $content));
&DoRmdir(&JoinPaths($dir, $content));
} else {
&DoUnlink(&JoinPaths($dir, $content));
}
}
}
sub StowContents {
my($dir, $stow) = @_;
warn "Stowing contents of $dir\n" if $opts{verbose} > 1;
my $joined = &JoinPaths($opts{stow}, $dir);
opendir(DIR, $joined)
|| die "$RealScript: Cannot read directory \"$dir\" ($!)\n";
my @contents = readdir(DIR);
closedir(DIR);
foreach my $content (@contents) {
# Wed Nov 23 2005 Adam Spiers
# hack to ignore stuff in ~/.cvsignore
next if $content eq '.' or $content eq '..';
if ($content =~ $ignore_re) {
# FIXME: We assume -r implies the open succeeded but this is not
# true if we're stowing cvs as .cvsignore only gets created
# halfway through.
warn "Ignoring $joined/$content", (-r $ignore_file ? " via $ignore_file" : ""), "\n"
if $opts{verbose} > 2;
next;
}
if (-d &JoinPaths($opts{stow}, $dir, $content)) {
&StowDir(&JoinPaths($dir, $content), $stow);
} else {
&StowNondir(&JoinPaths($dir, $content), $stow);
}
}
}
sub StowDir {
my($dir, $stow) = @_;
my(@dir) = split(/\/+/, $dir);
my($collection) = shift(@dir);
my($subdir) = &JoinPaths('/', @dir);
my($linktarget, $stowsubdir);
warn "Stowing directory $dir\n" if ($opts{verbose} > 1);
my $subdirPath = &JoinPaths($opts{target}, $subdir);
if (-l $subdirPath) {
($linktarget = readlink($subdirPath))
|| die "$RealScript: Could not read link $subdirPath ($!)\n";
my $stowsubdir = &FindStowMember(
&JoinPaths($opts{target}, @dir[0..($#dir - 1)]),
$linktarget
);
unless ($stowsubdir) {
&Conflict($dir, $subdir, 1);
return;
}
if (-e &JoinPaths($opts{stow}, $stowsubdir)) {
if ($stowsubdir eq $dir) {
warn sprintf("%s already points to %s\n",
$subdirPath,
&JoinPaths($opts{stow}, $dir))
if ($opts{verbose} > 2);
return;
}
if (-d &JoinPaths($opts{stow}, $stowsubdir)) {
# This is the splitting open of a folded tree which the stow
# manual refers to.
&DoUnlink($subdirPath);
&DoMkdir($subdirPath);
&StowContents($stowsubdir, &JoinPaths('..', $stow));
&StowContents($dir, &JoinPaths('..', $stow));
} else {
(&Conflict($dir, $subdir, 2), return);
}
} else {
&DoUnlink($subdirPath);
&DoLink(&JoinPaths($stow, $dir),
$subdirPath);
}
} elsif (-e $subdirPath) {
if (-d $subdirPath) {
&StowContents($dir, &JoinPaths('..', $stow));
} else {
&Conflict($dir, $subdir, 3);
}
} else {
&DoLink(&JoinPaths($stow, $dir),
$subdirPath);
}
}
sub StowNondir {
my($file, $stow) = @_;
my(@file) = split(/\/+/, $file);
my($collection) = shift(@file);
my($subfile) = &JoinPaths(@file);
my($linktarget, $stowsubfile);
my $subfilePath = &JoinPaths($opts{target}, $subfile);
if (-l $subfilePath) {
my $linktarget = readlink($subfilePath);
$linktarget or die "$RealScript: Could not read link $subfilePath ($!)\n";
my $stowsubfile = &FindStowMember(
&JoinPaths($opts{target}, @file[0..($#file - 1)]),
$linktarget
);
if (! $stowsubfile) {
&Conflict($file, $subfile, 4);
return;
}
if (-e &JoinPaths($opts{stow}, $stowsubfile)) {
(&Conflict($file, $subfile, 5), return)
unless ($stowsubfile eq $file);
warn sprintf("%s already points to %s\n",
$subfilePath,
&JoinPaths($opts{stow}, $file))
if ($opts{verbose} > 2);
} else {
&DoUnlink($subfilePath);
&DoLink(&JoinPaths($stow, $file), $subfilePath);
}
} elsif (-e $subfilePath) {
&Conflict($file, $subfile, 6);
} else {
&DoLink(&JoinPaths($stow, $file), $subfilePath);
}
}
sub DoUnlink {
my($file) = @_;
warn "UNLINK $file\n" if $opts{verbose};
(unlink($file) || die "$RealScript: Could not unlink $file ($!)\n")
unless $opts{not_really};
}
sub DoRmdir {
my($dir) = @_;
warn "RMDIR $dir\n" if $opts{verbose};
(rmdir($dir) || die "$RealScript: Could not rmdir $dir ($!)\n")
unless $opts{not_really};
}
sub DoLink {
my($target, $name) = @_;
warn "LINK $name to $target\n" if $opts{verbose};
(symlink($target, $name) ||
die "$RealScript: Could not symlink $name to $target ($!)\n")
unless $opts{not_really};
}
sub DoMkdir {
my($dir) = @_;
warn "MKDIR $dir\n" if $opts{verbose};
(mkdir($dir, 0777)
|| die "$RealScript: Could not make directory $dir ($!)\n")
unless $opts{not_really};
}
sub Conflict {
my($a, $b, $type) = @_;
my $src = &JoinPaths($opts{stow}, $a);
my $dst = &JoinPaths($opts{target}, $b);
if ($opts{conflicts}) {
warn "CONFLICT: $src vs. $dst", ($type ? " ($type)" : ''), "\n";
#system "ls -l $src $dst";
} else {
die "$RealScript: CONFLICT: $src vs. $dst", ($type ? " ($type)" : ''), "\n";
}
}
# Given an absolute starting directory and a relative path obtained by
# calling readlink() on a symlink in that starting directory,
# FindStowMember() figures out whether the symlink points to somewhere
# within the stow directory. If so, it returns the target of the
# symlink relative to the stow directory, otherwise it returns ''.
sub FindStowMember {
my($startDir, $targetPath) = @_;
my @startDirSegments = split(/\/+/, $startDir);
my @targetSegments = split(/\/+/, $targetPath);
my @stowDirSegments = split(/\/+/, $opts{stow});
# Start in $startDir and navigate to target, one path segment at a time.
my @current = @startDirSegments;
while (@targetSegments) {
my $x = shift(@targetSegments);
if ($x eq '..') {
pop(@current);
return '' unless @current; # We can't go higher than /, must be
# an invalid symlink.
} elsif ($x) {
push(@current, $x);
}
}
# Now @current describes the absolute path to the symlink's target,
# so if @current and @stowDirSegments have a common prefix, the
# symlink points within the stow directory.
while (@current && @stowDirSegments) {
if (shift(@current) ne shift(@stowDirSegments)) {
return '';
}
}
return '' if @stowDirSegments;
return join('/', @current);
}
sub parent {
my($path) = join('/', @_);
my(@elts) = split(/\/+/, $path);
pop(@elts);
return join('/', @elts);
}
sub get_ignore_re_from_file {
my ($file) = @_;
# Bootstrap issue - first time we stow, we will be stowing
# .cvsignore so it won't exist in ~ yet. At that time, use
# a sensible default instead.
open(REGEXPS, $file) or return qr!\.cfgsave\.|^(CVS)$!;
my @regexps;
while (<REGEXPS>) {
chomp;
push @regexps, glob_to_re($_);
}
close(REGEXPS);
my $re = join '|', @regexps;
warn "#% ignore regexp is $re\n" if $opts{verbose};
return qr/$re/;
}
1;