forked from samg/diffy
/
diff.rb
181 lines (159 loc) · 5.15 KB
/
diff.rb
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module Diffy
class Diff
ORIGINAL_DEFAULT_OPTIONS = {
:diff => '-U10000',
:source => 'strings',
:include_diff_info => false,
:include_plus_and_minus_in_html => false,
:context => nil,
:allow_empty_diff => true,
}
class << self
attr_writer :default_format
def default_format
@default_format ||= :text
end
# default options passed to new Diff objects
attr_writer :default_options
def default_options
@default_options ||= ORIGINAL_DEFAULT_OPTIONS.dup
end
end
include Enumerable
attr_reader :string1, :string2, :options
# supported options
# +:diff+:: A cli options string passed to diff
# +:source+:: Either _strings_ or _files_. Determines whether string1
# and string2 should be interpreted as strings or file paths.
# +:include_diff_info+:: Include diff header info
# +:include_plus_and_minus_in_html+:: Show the +, -, ' ' at the
# beginning of lines in html output.
def initialize(string1, string2, options = {})
@options = self.class.default_options.merge(options)
if ! ['strings', 'files'].include?(@options[:source])
raise ArgumentError, "Invalid :source option #{@options[:source].inspect}. Supported options are 'strings' and 'files'."
end
@string1, @string2 = string1, string2
end
def diff
@diff ||= begin
@paths = case options[:source]
when 'strings'
[tempfile(string1), tempfile(string2)]
when 'files'
[string1, string2]
end
if WINDOWS
# don't use open3 on windows
cmd = sprintf '"%s" %s %s', diff_bin, diff_options.join(' '), @paths.map { |s| %("#{s}") }.join(' ')
diff = `#{cmd}`
else
diff = Open3.popen3(diff_bin, *(diff_options + @paths)) { |i, o, e| o.read }
end
diff.force_encoding('ASCII-8BIT') if diff.respond_to?(:valid_encoding?) && !diff.valid_encoding?
if diff =~ /\A\s*\Z/ && !options[:allow_empty_diff]
diff = case options[:source]
when 'strings' then string1
when 'files' then File.read(string1)
end.gsub(/^/, " ")
end
diff
end
ensure
# unlink the tempfiles explicitly now that the diff is generated
if defined? @tempfiles # to avoid Ruby warnings about undefined ins var.
Array(@tempfiles).each do |t|
begin
# check that the path is not nil and file still exists.
# REE seems to be very agressive with when it magically removes
# tempfiles
t.unlink if t.path && File.exist?(t.path)
rescue => e
warn "#{e.class}: #{e}"
warn e.backtrace.join("\n")
end
end
end
end
def each
lines = case @options[:include_diff_info]
when false
# this "primes" the diff and sets up the paths we'll reference below.
diff
# caching this regexp improves the performance of the loop by a
# considerable amount.
regexp = /^(--- "?#{@paths[0]}"?|\+\+\+ "?#{@paths[1]}"?|@@|\\\\)/
diff.split("\n").reject{|x| x =~ regexp }.map {|line| line + "\n" }
when true
diff.split("\n").map {|line| line + "\n" }
end
if block_given?
lines.each{|line| yield line}
else
lines.to_enum
end
end
def each_chunk
old_state = nil
chunks = inject([]) do |cc, line|
state = line.each_char.first
if state == old_state
cc.last << line
else
cc.push line.dup
end
old_state = state
cc
end
if block_given?
chunks.each{|chunk| yield chunk }
else
chunks.to_enum
end
end
def tempfile(string)
t = Tempfile.new('diffy')
# ensure tempfiles aren't unlinked when GC runs by maintaining a
# reference to them.
@tempfiles ||=[]
@tempfiles.push(t)
t.print(string)
t.flush
t.close
t.path
end
def to_s(format = nil)
format ||= self.class.default_format
formats = Format.instance_methods(false).map{|x| x.to_s}
if formats.include? format.to_s
enum = self
enum.extend Format
enum.send format
else
raise ArgumentError,
"Format #{format.inspect} not found in #{formats.inspect}"
end
end
private
@@bin = nil
def diff_bin
return @@bin if @@bin
if @@bin = ENV['DIFFY_DIFF']
# system() trick from Minitest
raise "Can't execute diff program '#@@bin'" unless system(@@bin, __FILE__, __FILE__)
return @@bin
end
diffs = ['diff', 'ldiff']
diffs.first << '.exe' if WINDOWS # ldiff does not have exe extension
@@bin = diffs.find { |name| system(name, __FILE__, __FILE__) }
if @@bin.nil?
raise "Can't find a diff executable in PATH #{ENV['PATH']}"
end
@@bin
end
# options pass to diff program
def diff_options
Array(options[:context] ? "-U#{options[:context]}" : options[:diff])
end
end
end