git-strata.rb

#! /your/favourite/path/to/ruby
# -*- coding: utf-8 -*-
# Copyright (c) 2013 Urabe, Shyouhei
#
# Permission is hereby granted, free of  charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without  restriction, including without limitation the rights
# to  use, copy, modify,  merge, publish,  distribute, sublicense,  and/or sell
# copies  of the  Software,  and to  permit  persons to  whom  the Software  is
# furnished to do so, subject to the following conditions:
#
#    The above copyright notice and this permission notice shall be included
#    in all copies or substantial portions of the Software.
#
# THE SOFTWARE  IS PROVIDED "AS IS",  WITHOUT WARRANTY OF ANY  KIND, EXPRESS OR
# IMPLIED,  INCLUDING BUT  NOT LIMITED  TO THE  WARRANTIES  OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE  AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
# AUTHORS  OR COPYRIGHT  HOLDERS  BE LIABLE  FOR  ANY CLAIM,  DAMAGES OR  OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

def failed
	abort "cd WORKING_DIRECTORY && ruby #$0 PATH"
end

def parse_diff enum
	return Enumerator.new do |e|
		hunks = enum.slice_before %r/^@@/
		hunks.each do |t|
			next unless /^@@/.match t.first # cut header
			x = y = z = w = 0
			a = Array.new
			f = false
			t.each do |i|
				case i
				when /^@@ \-(\d+)(?:,(\d+))? \+(\d+)(?:,(\d+))? @@/ then
					x = $1.to_i
					y = ($2 || 1).to_i
					z = $3.to_i
					w = ($4 || 1).to_i
				when /^\+/ then
					a << $'
				end
			end
			unless w == a.size
				puts t
				raise [$path, [x, y, z, w], a.size].inspect
			end
			e.yield [x, y, z, a] if z != 0
		end
	end
end

def patch prev, title, hunks
	i = j = 1
	this  = hunks.each_with_object Array.new do |(x, y, z, w), r|
		n  = w.empty? ? z + 1 : z
		while i < n do
			r[i] = prev[j]
			i   += 1
			j   += 1
		end
		w.each do |l|
			r[i] = [[title, l], *prev[j]]
			i   += 1
		end
		j = y.zero? ? x + y + 1 : x + y
	end
	k = prev.size
	while j < k do
		this[i] = prev[j]
		i += 1
		j += 1
	end
	return this.freeze
end

$metas = Hash.new

def dump fp, buf
	strata = buf.map {|i| i.map {|j| j.first[0,7] } rescue [] }.
		map {|i| i.reverse.join ' -> ' }
	maxhis = strata.max_by {|i| i.length }.length
	maxnam = buf.map {|i|
		begin
			/^Author: +(.+)( \<.+\>)$/.match($metas[i.first.first].join)[1]
		rescue
			''
		end
	}.max_by {|i| i.length }.length rescue 1
	buf.each_with_index do |i, j|
		next unless i
		title, line = *i.first
		meta   = $metas[title].join
		author = /^Author: +(.+)( \<.+\>)$/.match(meta)[1]
		date   = /^Date: +(.+)$/.match(meta)[1]
		fp.printf "%-#{maxhis}s (%-#{maxnam}s %s) %s", \
			strata[j], author, date, line
	end
end

# ARGV handling
failed unless path = $path = ARGV.shift

# Check git
failed unless system "git", "log", path, out: IO::NULL, err: IO::NULL

# Get diffs
cmd = %W"git log --follow --no-color --no-min-parents --unified=0 --date=iso #{path}"

IO.popen cmd, 'rb' do |fp|
	buf = fp.each_line
	buf = buf.slice_before %r/^commit ([0-9a-f]+)/
	buf = buf.map do |commit|
		# path #1
		match = /^commit ([0-9a-f]+)$/.match commit.first # should match
		obj   = match[1]
		meta  = commit.slice_before %r/\A\n\z/
		meta  = meta.to_a # to_a is needed to pop from here
		diff  = meta.pop
		diff  = meta.pop until diff != ["\n"]
		meta.flatten!
		$metas.store obj, meta
		next obj, meta, parse_diff(diff)
	end
	buf = buf.to_a
	buf = buf.reverse
	buf = buf.inject [[]] do |r, (o, m, e)|
		# path #2
		this = patch r.last, o, e
		r << this
	end

	# buf here is equivalent to the list of git-blame output

	# path #3
	buf = buf.last
	if STDOUT.isatty
		pager = ENV['PAGER'] || 'less'
		IO.popen pager, 'wb' do |fp|
			dump fp, buf
		end
	else
		dump STDOUT, buf
	end
end

# 
# Local Variables:
# mode: ruby
# coding: utf-8-unix
# indent-tabs-mode: t
# tab-width: 3
# ruby-indent-level: 3
# fill-column: 79
# default-justification: full
# End: