Extracted AtomicWrite

tool/generic_erb.rb

@@ -6,30 +6,22 @@
 require 'erb'
 require 'optparse'
 require_relative 'lib/vpath'
-require_relative 'lib/colorize'
+require_relative 'lib/atomic_write'
 
 vpath = VPath.new
-timestamp = nil
-output = nil
-ifchange = nil
+aw = AtomicWrite.new
+aw.vpath = vpath
 source = false
-color = nil
 templates = []
 
 ARGV.options do |o|
-  o.on('-t', '--timestamp[=PATH]') {|v| timestamp = v || true}
   o.on('-i', '--input=PATH') {|v| template << v}
-  o.on('-o', '--output=PATH') {|v| output = v}
-  o.on('-c', '--[no-]if-change') {|v| ifchange = v}
   o.on('-x', '--source') {source = true}
-  o.on('--color') {color = true}
+  aw.def_options(o)
   vpath.def_options(o)
   o.order!(ARGV)
   templates << (ARGV.shift or abort o.to_s) if templates.empty?
 end
-color = Colorize.new(color)
-unchanged = color.pass("unchanged")
-updated = color.fail("updated")
 
 result = templates.map do |template|
   if ERB.instance_method(:initialize).parameters.assoc(:key) # Ruby 2.6+
@@ -41,21 +33,4 @@ result = templates.map do |template|
   source ? erb.src : proc{erb.result(binding)}.call
 end
 result = result.size == 1 ? result[0] : result.join("")
-if output
-  if ifchange and (vpath.open(output, "rb") {|f| f.read} rescue nil) == result
-    puts "#{output} #{unchanged}"
-  else
-    open(output, "wb") {|f| f.print result}
-    puts "#{output} #{updated}"
-  end
-  if timestamp
-    if timestamp == true
-      dir, base = File.split(output)
-      timestamp = File.join(dir, ".time." + base)
-    end
-    File.open(timestamp, 'a') {}
-    File.utime(nil, nil, timestamp)
-  end
-else
-  print result
-end
+aw.emit(result)

tool/lib/atomic_write.rb

@@ -0,0 +1,60 @@
+require 'optparse'
+require_relative 'vpath'
+require_relative 'colorize'
+
+class AtomicWrite
+  attr_accessor :vpath, :timestamp, :output, :compare :color
+
+  def initialize
+    @vpath = nil
+    @timestamp = nil
+    @output = nil
+    @compare = nil
+    @color = nil
+  end
+
+  def def_options(opt)
+    opt.on('-t', '--timestamp[=PATH]') {|v| @timestamp = v || true}
+    opt.on('-o', '--output=PATH') {|v| @output = v}
+    opt.on('-c', '--[no-]if-change') {|v| @compare = v}
+    opt.on('--color') {@color = true}
+    @vpath.def_options(opt) if @vpath
+    opt
+  end
+
+  def emit(result)
+    output = @output
+    if output
+      update output, result
+      stamp output
+    else
+      print result
+    end
+  end
+
+  def update(output, result)
+    color = Colorize.new(@color)
+    unchanged = color.pass("unchanged")
+    updated = color.fail("updated")
+    vpath = @vpath || File
+    if @compare and (vpath.open(output, "rb") {|f| f.read} rescue nil) == result
+      puts "#{output} #{unchanged}"
+      false
+    else
+      open(output, "wb") {|f| f.print result}
+      puts "#{output} #{updated}"
+      true
+    end
+  end
+
+  def stamp(output, timestamp = @timestamp)
+    if timestamp
+      if timestamp == true
+        dir, base = File.split(output)
+        timestamp = File.join(dir, ".time." + base)
+      end
+      File.open(timestamp, 'a') {}
+      File.utime(nil, nil, timestamp)
+    end
+  end
+end