splitpatch.rb

#!/usr/bin/env ruby
#
# splitpatch is a simple script to split a patch up into multiple patch files.
# if the --hunks option is provided on the command line, each hunk gets its
# own patchfile.
#
# Copyright (C) 2007 Peter Hutterer <peter@cs.unisa.edu.au>
#
# 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, 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, see <http://www.gnu.org/licenses/>.
#
# Changes
#
#    2013-06-10 Jari Aalto <jari.aalto@cante.net>
#
#    Use split parts separated by a dash(-), not dot(.) and which are
#    zero-based. Format: FILENAME-NNN.patch for hunks and
#    FILENAME.patch-NNN for regular files (if file already existsed).
#
#    Add options --help, --version and short option for -H (hunks).

PROGRAM = "splitpatch"
VERSION = 0.1
LICENSE = "GPL-2+"  # See official acronyms: https://spdx.org/licenses/
AUTHOR  = "Peter Hutterer <peter@cs.unisa.edu.au>"

class Splitter
   def initialize(file)
       @filename = file
    end

    def validFile?
        return File.exist?(@filename) && File.readable?(@filename)
    end

    # Split the patchfile by files
    def splitByFile
        outfile = nil
        stream = open(@filename)
        until (stream.eof?)
            line = stream.readline

            # we need to create a new file
            if (line =~ /--- .*/) == 0
                if (outfile)
                    outfile.close_write
                end
                #find filename
                tokens = line.split(" ")
                tokens = tokens[1].split(":")
                tokens = tokens[0].split("/")
                filename = tokens[-1]
                filename << ".patch"
                if File.exists?(filename)
                    puts "File #{filename} already exists. Renaming patch."
                    appendix = 0
                    zero = appendix.to_s.rjust(3, '0')
                    while File.exists?("#{filename}-#{zero}")
                        appendix += 1
                    end
                    filename << "-#{zero}"
                end
                outfile = open(filename, "w")
                outfile.write(line)
            else
                if outfile
                    outfile.write(line)
                end
            end
        end
    end

    def splitByHunk
        outfile = nil
        stream = open(@filename)
        filename = ""
        counter = 0
        header = ""
        until (stream.eof?)
            line = stream.readline

            # we need to create a new file
            if (line =~ /--- .*/) == 0
                #find filename
                tokens = line.split(" ")
                tokens = tokens[1].split(":")
                tokens = tokens[0].split("/")
                filename = tokens[-1]
                header = line
                # next line is header too
                line = stream.readline
                header << line
                counter = 0
            elsif (line =~ /@@ .* @@/) == 0
                if (outfile)
                    outfile.close_write
                end
                zero = counter.to_s.rjust(3, '0')
                hunkfilename = "#{filename}-#{zero}.patch"
                if File.exists?(hunkfilename)
                    puts "File #{hunkfilename} already exists. Renaming patch."
                    appendix = 0
                    zero = appendix.to_s.rjust(3, '0')
                    while File.exists?("#{hunkfilename}-#{zero}")
                        appendix += 1
                    end
                    hunkfilename << "-#{zero}"
                end
                outfile = open(hunkfilename, "w")
                counter += 1

                outfile.write(header)
                outfile.write(line)
            else
                if outfile
                    outfile.write(line)
                end
            end
        end
    end

end

def help
    puts <<EOF
SYNOPSIS
    #{PROGRAM} [options] FILE.patch

OPTIONS
    -h,--help
    -H,--hunk
    -V,--version

DESCRIPTION

    Split the patch up into files or hunks

    Divide a patch or diff file into pieces. The split can made by file
    or by hunk basis. This makes is possible to separate changes that
    might not be desireable or assemble the patch into more coherent set
    of changes. See e.g. combinediff(1) from patchutils package.
EOF
end

def version
  puts "#{VERSION} #{LICENSE} #{AUTHOR}"
end

########################     MAIN     ########################


if ARGV.length < 1 or ARGV.length > 2
    puts "Wrong parameter. Usage: splitpatch.rb [--hunks] <patchfile>"
    exit 1
elsif ARGV[0] == "--help"
    puts "splitpatch splits a patch that is supposed to patch multiple files"
    puts "into a set of patches."
    puts "Currently splits unified diff patches."
    puts "If the --hunk option is given, a new file is created for each hunk."
    exit 1
else
    opt = ARGV[0]
    if /^-h$|--help/.match(opt)
        help
        exit 0
    elsif /^-H$|--hunks?/.match(opt)
        hunk = 1
    elsif /^-V$|--version/.match(opt)
        version
        exit 0
    elsif /^-/.match(opt)
        puts "ERROR: Unknonw option: #{opt}. See --help."
        exit 1
    end
    file = ARGV[-1]
    s = Splitter.new(file)
    if s.validFile?
        if hunk
            s.splitByHunk
        else
            s.splitByFile
        end
    else
        puts "File does not exist or is not readable: #{file}"
    end
end

# End of file