sathishmanohar/show_method_history.rb

## show_method_history.rb
#!/usr/bin/env ruby
# Given a file and method_name
# Show all the different implementations across the git history (first commit per implementation).
#
#   show_method_history <file> <method_name> --html
#
#   e.g. show_method_history test/test_helper.rb sign_in --html
#
# WARNING: the --html output just dumps html files into your current folder.
#
require 'parser/current'
require 'digest'
require 'stringio'
require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem 'coderay', '~> 1.1.3'
end

require 'coderay'

Commit = Struct.new(:hash, :author, :email, :date, :message)
Implementation = Struct.new(:file, :name, :ast, :src, :sha1, :commit) do
  def to_terminal
    <<~STR
      # method sha1: #{sha1}
      # commit : #{commit.hash}
      # author: #{commit.author}
      # date: #{commit.date}
      # message: #{commit.message}
      #{CodeRay.highlight(src, :ruby, {}, :term)}
    STR
  end
end

def find_methods_ast(ast)
  return unless ast.is_a?(Parser::AST::Node)
  methods = []
  case ast.type
  when :class, :module, :begin
    methods.concat(ast.children.flat_map {|child| find_methods_ast(child) })
  when :def
    methods << ast
  end
  methods
end

def find_methods_file(file, file_content)
  code = file_content.read
  #p code: code
  ast = Parser::CurrentRuby.parse(code)
  find_methods_ast(ast)
end

def implementation_from_method_ast(file, file_content, method_ast, commit)
  name = method_ast.to_a.first
  first_line = method_ast.location.first_line - 1
  last_line = method_ast.location.last_line

  file_content.rewind
  src = file_content.readlines[first_line...last_line].join

  sha1 = Digest::SHA1.hexdigest src
  Implementation.new(file, name, method_ast, src, sha1, commit)
end

def implementation_from_file(file, file_content, method_name, commit)
  methods = find_methods_file(file, file_content)
  method_ast = methods.find{|meth| meth.to_a.first == method_name }
  return nil if method_ast.nil?
  implementation_from_method_ast(file, file_content, method_ast, commit)
end

def commits_from_file(file)
  results = `git log --pretty="%H\t%aN\t%aE\t%aD\t%s" #{file}`
  results.lines.reverse.map{|line| Commit.new(*line.split("\t")) }
end

def file_at_version(filename, version_hash)
  # puts "git show #{version_hash}:#{filename}"
  StringIO.new(`git show #{version_hash}:#{filename}`)
end


if __FILE__ == $0

  if ARGV.size.zero?
    puts <<~USAGE
      Search files for specific method, group by hash of method src.

        show_method_history <file> <method_name>

        show_method_history <file> <method_name> --html

        e.g. show_method_history test/test_helper.rb sign_in
    USAGE
    exit
  end

  implementations = []

  filename, method_name, opt, = ARGV
  method_name = method_name.to_sym
  seen_method_hashes = Set.new
  commits_from_file(filename).each do |commit|
    file_content = file_at_version(filename, commit.hash)
    implementation = implementation_from_file(filename, file_content, method_name, commit)
    next if implementation.nil?
    next if seen_method_hashes.include?(implementation.sha1)

    implementations << implementation
    seen_method_hashes << implementation.sha1
  end

  if opt == '--html'
    html_file_name = ->(impl, i){ "#{i}_#{impl.name}.html" }
    prev_impl = nil
    implementations.each_with_index do |impl, i|
      next_impl = implementations[i + 1]
      html = StringIO.new
      html << "<html><head>"
      html << '<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/water.css@2/out/water.css">'
      html << "</head><body>"
      html << "<table><tr>"
      html << "<td><a href='#{html_file_name.call(implementations.first, 0)}'>first</a>"
      html << "<td>prev" if prev_impl.nil?
      html << "<td><a href='#{html_file_name.call(prev_impl, i - 1)}'>prev</a>" unless prev_impl.nil?
      html << "<td>next" if next_impl.nil?
      html << "<td><a href='#{html_file_name.call(next_impl, i + 1)}'>next</a>" unless next_impl.nil?
      html << "<td><a href='#{html_file_name.call(implementations.last, implementations.count - 1)}'>last</a>"
      html << "</table>"
      commit = impl.commit
      html << <<~STR
        <dl>
        <dt>method sha1 <dd>#{impl.sha1}
          <dt>commit <dd>#{commit.hash}
          <dt>author <dd>#{commit.author}
          <dt>date <dd>#{commit.date}
          <dt>message <dd>#{commit.message}
        </dl>
        <div class='CodeRay'>
        #{CodeRay.scan(impl.src, :ruby).html(wrap: :div, line_numbers: :inline, css: :style)}
        </div>
      STR

      current_filename = html_file_name.call(impl, i)
      File.write current_filename, html.string
      puts "file://#{File.expand_path(current_filename)}"

      prev_impl = impl
    end
  else
    implementations.each do |impl|
      puts impl.to_terminal
      puts
    end
  end

end
	#!/usr/bin/env ruby
	# Given a file and method_name
	# Show all the different implementations across the git history (first commit per implementation).
	#
	# show_method_history <file> <method_name> --html
	#
	# e.g. show_method_history test/test_helper.rb sign_in --html
	#
	# WARNING: the --html output just dumps html files into your current folder.
	#
	require 'parser/current'
	require 'digest'
	require 'stringio'
	require 'bundler/inline'

	gemfile do
	source 'https://rubygems.org'
	gem 'coderay', '~> 1.1.3'
	end

	require 'coderay'

	Commit = Struct.new(:hash, :author, :email, :date, :message)
	Implementation = Struct.new(:file, :name, :ast, :src, :sha1, :commit) do
	def to_terminal
	<<~STR
	# method sha1: #{sha1}
	# commit : #{commit.hash}
	# author: #{commit.author}
	# date: #{commit.date}
	# message: #{commit.message}
	#{CodeRay.highlight(src, :ruby, {}, :term)}
	STR
	end
	end

	def find_methods_ast(ast)
	return unless ast.is_a?(Parser::AST::Node)
	methods = []
	case ast.type
	when :class, :module, :begin
	methods.concat(ast.children.flat_map {\|child\| find_methods_ast(child) })
	when :def
	methods << ast
	end
	methods
	end

	def find_methods_file(file, file_content)
	code = file_content.read
	#p code: code
	ast = Parser::CurrentRuby.parse(code)
	find_methods_ast(ast)
	end

	def implementation_from_method_ast(file, file_content, method_ast, commit)
	name = method_ast.to_a.first
	first_line = method_ast.location.first_line - 1
	last_line = method_ast.location.last_line

	file_content.rewind
	src = file_content.readlines[first_line...last_line].join

	sha1 = Digest::SHA1.hexdigest src
	Implementation.new(file, name, method_ast, src, sha1, commit)
	end

	def implementation_from_file(file, file_content, method_name, commit)
	methods = find_methods_file(file, file_content)
	method_ast = methods.find{\|meth\| meth.to_a.first == method_name }
	return nil if method_ast.nil?
	implementation_from_method_ast(file, file_content, method_ast, commit)
	end

	def commits_from_file(file)
	results = `git log --pretty="%H\t%aN\t%aE\t%aD\t%s" #{file}`
	results.lines.reverse.map{\|line\| Commit.new(*line.split("\t")) }
	end

	def file_at_version(filename, version_hash)
	# puts "git show #{version_hash}:#{filename}"
	StringIO.new(`git show #{version_hash}:#{filename}`)
	end


	if __FILE__ == $0

	if ARGV.size.zero?
	puts <<~USAGE
	Search files for specific method, group by hash of method src.

	show_method_history <file> <method_name>

	show_method_history <file> <method_name> --html

	e.g. show_method_history test/test_helper.rb sign_in
	USAGE
	exit
	end

	implementations = []

	filename, method_name, opt, = ARGV
	method_name = method_name.to_sym
	seen_method_hashes = Set.new
	commits_from_file(filename).each do \|commit\|
	file_content = file_at_version(filename, commit.hash)
	implementation = implementation_from_file(filename, file_content, method_name, commit)
	next if implementation.nil?
	next if seen_method_hashes.include?(implementation.sha1)

	implementations << implementation
	seen_method_hashes << implementation.sha1
	end

	if opt == '--html'
	html_file_name = ->(impl, i){ "#{i}_#{impl.name}.html" }
	prev_impl = nil
	implementations.each_with_index do \|impl, i\|
	next_impl = implementations[i + 1]
	html = StringIO.new
	html << "<html><head>"
	html << '<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/water.css@2/out/water.css">'
	html << "</head><body>"
	html << "<table><tr>"
	html << "<td><a href='#{html_file_name.call(implementations.first, 0)}'>first</a>"
	html << "<td>prev" if prev_impl.nil?
	html << "<td><a href='#{html_file_name.call(prev_impl, i - 1)}'>prev</a>" unless prev_impl.nil?
	html << "<td>next" if next_impl.nil?
	html << "<td><a href='#{html_file_name.call(next_impl, i + 1)}'>next</a>" unless next_impl.nil?
	html << "<td><a href='#{html_file_name.call(implementations.last, implementations.count - 1)}'>last</a>"
	html << "</table>"
	commit = impl.commit
	html << <<~STR
	<dl>
	<dt>method sha1 <dd>#{impl.sha1}
	<dt>commit <dd>#{commit.hash}
	<dt>author <dd>#{commit.author}
	<dt>date <dd>#{commit.date}
	<dt>message <dd>#{commit.message}
	</dl>
	<div class='CodeRay'>
	#{CodeRay.scan(impl.src, :ruby).html(wrap: :div, line_numbers: :inline, css: :style)}
	</div>
	STR

	current_filename = html_file_name.call(impl, i)
	File.write current_filename, html.string
	puts "file://#{File.expand_path(current_filename)}"

	prev_impl = impl
	end
	else
	implementations.each do \|impl\|
	puts impl.to_terminal
	puts
	end
	end

	end