1 files changed, 70 insertions, 0 deletions
diff --git a/tool/lib/output.rb b/tool/lib/output.rb
new file mode 100644
index 0000000000..8cb426ae4a
--- /dev/null
+++ b/tool/lib/output.rb
@@ -0,0 +1,70 @@
+require_relative 'vpath'
+require_relative 'colorize'
+
+class Output
+  attr_reader :path, :vpath
+
+  def initialize(path: nil, timestamp: nil, ifchange: nil, color: nil,
+                 overwrite: false, create_only: false, vpath: VPath.new)
+    @path = path
+    @timestamp = timestamp
+    @ifchange = ifchange
+    @color = color
+    @overwrite = overwrite
+    @create_only = create_only
+    @vpath = vpath
+  end
+
+  COLOR_WHEN = {
+    'always' => true, 'auto' => nil, 'never' => false,
+    nil => true, false => false,
+  }
+
+  def def_options(opt)
+    opt.separator("  Output common options:")
+    opt.on('-o', '--output=PATH') {|v| @path = v}
+    opt.on('-t', '--timestamp[=PATH]') {|v| @timestamp = v || true}
+    opt.on('-c', '--[no-]if-change') {|v| @ifchange = v}
+    opt.on('--[no-]color=[WHEN]', COLOR_WHEN.keys) {|v| @color = COLOR_WHEN[v]}
+    opt.on('--[no-]create-only') {|v| @create_only = v}
+    opt.on('--[no-]overwrite') {|v| @overwrite = v}
+    @vpath.def_options(opt)
+  end
+
+  def write(data, overwrite: @overwrite, create_only: @create_only)
+    unless @path
+      $stdout.print data
+      return true
+    end
+    color = Colorize.new(@color)
+    unchanged = color.pass("unchanged")
+    updated = color.fail("updated")
+    outpath = nil
+
+    if (@ifchange or overwrite or create_only) and (@vpath.open(@path, "rb") {|f|
+      outpath = f.path
+      if @ifchange or create_only
+        original = f.read
+        (@ifchange and original == data) or (create_only and !original.empty?)
+      end
+    } rescue false)
+      puts "#{outpath} #{unchanged}"
+      written = false
+    else
+      unless overwrite and outpath and (File.binwrite(outpath, data) rescue nil)
+        File.binwrite(outpath = @path, data)
+      end
+      puts "#{outpath} #{updated}"
+      written = true
+    end
+    if timestamp = @timestamp
+      if timestamp == true
+        dir, base = File.split(@path)
+        timestamp = File.join(dir, ".time." + base)
+      end
+      File.binwrite(timestamp, '')
+      File.utime(nil, nil, timestamp)
+    end
+    written
+  end
+end