git

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#!/usr/bin/perl
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#
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# Copyright 2008-2009 Peter Krefting <peter@softwolves.pp.se>
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#
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# ------------------------------------------------------------------------
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, see <http://www.gnu.org/licenses/>.
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#
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# ------------------------------------------------------------------------
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=pod
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=head1 NAME
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import-directories - Import bits and pieces to Git.
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=head1 SYNOPSIS
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B<import-directories.perl> F<configfile> F<outputfile>
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=head1 DESCRIPTION
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Script to import arbitrary projects version controlled by the "copy the
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source directory to a new location and edit it there"-version controlled
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projects into version control. Handles projects with arbitrary branching
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and version trees, taking a file describing the inputs and generating a
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file compatible with the L<git-fast-import(1)> format.
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=head1 CONFIGURATION FILE
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=head2 Format
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The configuration file is based on the standard I<.ini> format.
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 ; Comments start with semi-colons
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 [section]
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 key=value
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Please see below for information on how to escape special characters.
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=head2 Global configuration
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Global configuration is done in the B<[config]> section, which should be
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the first section in the file. Configuration can be changed by
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repeating configuration sections later on.
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 [config]
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 ; configure conversion of CRLFs. "convert" means that all CRLFs
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 ; should be converted into LFs (suitable for the core.autocrlf
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 ; setting set to true in Git). "none" means that all data is
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 ; treated as binary.
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 crlf=convert
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=head2 Revision configuration
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Each revision that is to be imported is described in three
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sections. Revisions should be defined in topological order, so
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that a revision's parent has always been defined when a new revision
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is introduced. All the sections for one revision must be defined
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before defining the next revision.
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Each revision is assigned a unique numerical identifier. The
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numbers do not need to be consecutive, nor monotonically
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increasing.
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For instance, if your configuration file contains only the two
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revisions 4711 and 42, where 4711 is the initial commit, the
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only requirement is that 4711 is completely defined before 42.
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=pod
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=head3 Revision description section
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A section whose section name is just an integer gives meta-data
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about the revision.
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 [3]
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 ; author sets the author of the revisions
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 author=Peter Krefting <peter@softwolves.pp.se>
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 ; branch sets the branch that the revision should be committed to
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 branch=master
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 ; parent describes the revision that is the parent of this commit
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 ; (optional)
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 parent=1
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 ; merges describes a revision that is merged into this commit
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 ; (optional; can be repeated)
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 merges=2
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 ; selects one file to take the timestamp from
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 ; (optional; if unspecified, the most recent file from the .files
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 ;  section is used)
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 timestamp=3/source.c
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=head3 Revision contents section
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A section whose section name is an integer followed by B<.files>
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describe all the files included in this revision. If a file that
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was available previously is not included in this revision, it will
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be removed.
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If an on-disk revision is incomplete, you can point to files from
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a previous revision. There are no restrictions on where the source
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files are located, nor on their names.
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 [3.files]
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 ; the key is the path inside the repository, the value is the path
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 ; as seen from the importer script.
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 source.c=ver-3.00/source.c
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 source.h=ver-2.99/source.h
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 readme.txt=ver-3.00/introduction to the project.txt
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File names are treated as byte strings (but please see below on
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quoting rules), and should be stored in the configuration file in
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the encoding that should be used in the generated repository.
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=head3 Revision commit message section
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A section whose section name is an integer followed by B<.message>
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gives the commit message. This section is read verbatim, up until
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the beginning of the next section. As such, a commit message may not
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contain a line that begins with an opening square bracket ("[") and
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ends with a closing square bracket ("]"), unless they are surrounded
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by whitespace or other characters.
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 [3.message]
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 Implement foobar.
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 ; trailing blank lines are ignored.
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=cut
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# Globals
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use strict;
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use warnings;
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use integer;
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my $crlfmode = 0;
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my @revs;
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my (%revmap, %message, %files, %author, %branch, %parent, %merges, %time, %timesource);
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my $sectiontype = 0;
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my $rev = 0;
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my $mark = 1;
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# Check command line
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if ($#ARGV < 1 || $ARGV[0] =~ /^--?h/)
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{
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    exec('perldoc', $0);
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    exit 1;
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}
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# Open configuration
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my $config = $ARGV[0];
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open CFG, '<', $config or die "Cannot open configuration file \"$config\": ";
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# Open output
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my $output = $ARGV[1];
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open OUT, '>', $output or die "Cannot create output file \"$output\": ";
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binmode OUT;
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LINE: while (my $line = <CFG>)
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{
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	$line =~ s/\r?\n$//;
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	next LINE if $sectiontype != 4 && $line eq '';
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	next LINE if $line =~ /^;/;
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	my $oldsectiontype = $sectiontype;
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	my $oldrev = $rev;
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	# Sections
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	if ($line =~ m"^\[(config|(\d+)(|\.files|\.message))\]$")
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	{
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		if ($1 eq 'config')
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		{
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			$sectiontype = 1;
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		}
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		elsif ($3 eq '')
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		{
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			$sectiontype = 2;
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			$rev = $2;
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			# Create a new revision
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			die "Duplicate rev: $line\n " if defined $revmap{$rev};
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			print "Reading revision $rev\n";
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			push @revs, $rev;
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			$revmap{$rev} = $mark ++;
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			$time{$revmap{$rev}} = 0;
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		}
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		elsif ($3 eq '.files')
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		{
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			$sectiontype = 3;
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			$rev = $2;
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			die "Revision mismatch: $line\n " unless $rev == $oldrev;
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		}
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		elsif ($3 eq '.message')
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		{
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			$sectiontype = 4;
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			$rev = $2;
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			die "Revision mismatch: $line\n " unless $rev == $oldrev;
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		}
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		else
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		{
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			die "Internal parse error: $line\n ";
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		}
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		next LINE;
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	}
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	# Parse data
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	if ($sectiontype != 4)
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	{
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		# Key and value
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		if ($line =~ m"^\s*([^\s].*=.*[^\s])\s*$")
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		{
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			my ($key, $value) = &parsekeyvaluepair($1);
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			# Global configuration
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			if (1 == $sectiontype)
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			{
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				if ($key eq 'crlf')
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				{
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					$crlfmode = 1, next LINE if $value eq 'convert';
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					$crlfmode = 0, next LINE if $value eq 'none';
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				}
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				die "Unknown configuration option: $line\n ";
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			}
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			# Revision specification
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			if (2 == $sectiontype)
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			{
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				my $current = $revmap{$rev};
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				$author{$current} = $value, next LINE if $key eq 'author';
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				$branch{$current} = $value, next LINE if $key eq 'branch';
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				$parent{$current} = $value, next LINE if $key eq 'parent';
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				$timesource{$current} = $value, next LINE if $key eq 'timestamp';
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				push(@{$merges{$current}}, $value), next LINE if $key eq 'merges';
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				die "Unknown revision option: $line\n ";
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			}
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			# Filespecs
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			if (3 == $sectiontype)
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			{
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				# Add the file and create a marker
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				die "File not found: $line\n " unless -f $value;
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				my $current = $revmap{$rev};
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				${$files{$current}}{$key} = $mark;
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				my $time = &fileblob($value, $crlfmode, $mark ++);
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				# Update revision timestamp if more recent than other
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				# files seen, or if this is the file we have selected
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				# to take the time stamp from using the "timestamp"
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				# directive.
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				if ((defined $timesource{$current} && $timesource{$current} eq $value)
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				    || $time > $time{$current})
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				{
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					$time{$current} = $time;
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				}
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			}
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		}
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		else
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		{
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			die "Parse error: $line\n ";
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		}
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	}
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	else
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	{
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		# Commit message
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		my $current = $revmap{$rev};
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		if (defined $message{$current})
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		{
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			$message{$current} .= "\n";
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		}
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		$message{$current} .= $line;
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	}
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}
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close CFG;
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# Start spewing out data for git-fast-import
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foreach my $commit (@revs)
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{
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	# Progress
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	print OUT "progress Creating revision $commit\n";
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	# Create commit header
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	my $mark = $revmap{$commit};
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	# Branch and commit id
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	print OUT "commit refs/heads/", $branch{$mark}, "\nmark :", $mark, "\n";
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	# Author and timestamp
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	die "No timestamp defined for $commit (no files?)\n" unless defined $time{$mark};
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	print OUT "committer ", $author{$mark}, " ", $time{$mark}, " +0100\n";
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	# Commit message
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	die "No message defined for $commit\n" unless defined $message{$mark};
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	my $message = $message{$mark};
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	$message =~ s/\n$//; # Kill trailing empty line
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	print OUT "data ", length($message), "\n", $message, "\n";
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	# Parent and any merges
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	print OUT "from :", $revmap{$parent{$mark}}, "\n" if defined $parent{$mark};
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	if (defined $merges{$mark})
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	{
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		foreach my $merge (@{$merges{$mark}})
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		{
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			print OUT "merge :", $revmap{$merge}, "\n";
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		}
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	}
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	# Output file marks
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	print OUT "deleteall\n"; # start from scratch
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	foreach my $file (sort keys %{$files{$mark}})
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	{
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		print OUT "M 644 :", ${$files{$mark}}{$file}, " $file\n";
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	}
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	print OUT "\n";
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}
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# Create one file blob
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sub fileblob
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{
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	my ($filename, $crlfmode, $mark) = @_;
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	# Import the file
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	print OUT "progress Importing $filename\nblob\nmark :$mark\n";
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	open FILE, '<', $filename or die "Cannot read $filename\n ";
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	binmode FILE;
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	my ($size, $mtime) = (stat(FILE))[7,9];
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	my $file;
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	read FILE, $file, $size;
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	close FILE;
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	$file =~ s/\r\n/\n/g if $crlfmode;
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	print OUT "data ", length($file), "\n", $file, "\n";
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	return $mtime;
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}
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# Parse a key=value pair
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sub parsekeyvaluepair
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{
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=pod
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=head2 Escaping special characters
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Key and value strings may be enclosed in quotes, in which case
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whitespace inside the quotes is preserved. Additionally, an equal
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sign may be included in the key by preceding it with a backslash.
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For example:
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 "key1 "=value1
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 key2=" value2"
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 key\=3=value3
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 key4=value=4
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 "key5""=value5
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Here the first key is "key1 " (note the trailing white-space) and the
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second value is " value2" (note the leading white-space). The third
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key contains an equal sign "key=3" and so does the fourth value, which
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does not need to be escaped. The fifth key contains a trailing quote,
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which does not need to be escaped since it is inside a surrounding
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quote.
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=cut
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	my $pair = shift;
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	# Separate key and value by the first non-quoted equal sign
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	my ($key, $value);
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	if ($pair =~ /^(.*[^\\])=(.*)$/)
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	{
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		($key, $value) = ($1, $2)
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	}
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	else
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	{
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		die "Parse error: $pair\n ";
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	}
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	# Unquote and unescape the key and value separately
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	return (&unescape($key), &unescape($value));
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}
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# Unquote and unescape
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sub unescape
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{
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	my $string = shift;
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	# First remove enclosing quotes. Backslash before the trailing
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	# quote leaves both.
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	if ($string =~ /^"(.*[^\\])"$/)
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	{
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		$string = $1;
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	}
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	# Second remove any backslashes inside the unquoted string.
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	# For later: Handle special sequences like \t ?
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	$string =~ s/\\(.)/$1/g;
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	return $string;
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}
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__END__
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=pod
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=head1 EXAMPLES
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B<import-directories.perl> F<project.import>
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=head1 AUTHOR
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Copyright 2008-2009 Peter Krefting E<lt>peter@softwolves.pp.se>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation.
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=cut
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