add generic Manpage module

lib/gist/manpage.rb

@@ -0,0 +1,90 @@
+module Gist
+  module Manpage
+    extend self
+
+    # Prints a manpage, all pretty and paged.
+    def display(name)
+      puts manpage(name)
+    end
+
+    # Returns the terminal-formatted manpage, ready to be printed to
+    # the screen.
+    def manpage(name)
+      return "** Can't find groff(1)" unless groff?
+
+      require 'open3'
+      out = nil
+      Open3.popen3(groff_command) do |stdin, stdout, _|
+        stdin.puts raw_manpage(name)
+        stdin.close
+        out = stdout.read.strip
+      end
+      out
+    end
+
+    # Returns the raw manpage. If we're not running in standalone
+    # mode, it's a file sitting at the root under the `man`
+    # directory.
+    #
+    # If we are running in standalone mode the manpage will be
+    # included after the __END__ of the file so we can grab it using
+    # DATA.
+    def raw_manpage(name)
+      if File.exists? file = File.dirname(__FILE__) + "/../../man/#{name}.1"
+        File.read(file)
+      else
+        DATA.read
+      end
+    end
+
+    # Returns true if groff is installed and in our path, false if
+    # not.
+    def groff?
+      system("which groff > /dev/null")
+    end
+
+    # The groff command complete with crazy arguments we need to run
+    # in order to turn our raw roff (manpage markup) into something
+    # readable on the terminal.
+    def groff_command
+      "groff -Wall -mtty-char -mandoc -Tascii"
+    end
+
+    # All calls to `puts` are paged, git-style.
+    def puts(*args)
+      page_stdout
+      super
+    end
+
+    # http://nex-3.com/posts/73-git-style-automatic-paging-in-ruby
+    def page_stdout
+      return unless $stdout.tty?
+
+      read, write = IO.pipe
+
+      if Kernel.fork
+        # Parent process, become pager
+        $stdin.reopen(read)
+        read.close
+        write.close
+
+        # Don't page if the input is short enough
+        ENV['LESS'] = 'FSRX'
+
+        # Wait until we have input before we start the pager
+        Kernel.select [STDIN]
+
+        pager = ENV['PAGER'] || 'less -isr'
+        pager = 'cat' if pager.empty?
+
+        exec pager rescue exec "/bin/sh", "-c", pager
+      else
+        # Child process
+        $stdout.reopen(write)
+        $stderr.reopen(write) if $stderr.tty?
+        read.close
+        write.close
+      end
+    end
+  end
+end

lib/gist/standalone.rb

@@ -9,7 +9,7 @@ module Standalone
 # Please DO NOT EDIT or send patches for it.
 #
 # Please take a look at the source from
-# http://gitgist.com/defunkt/gist
+# http://github.com/defunkt/gist
 # and submit patches against the individual files
 # that build gist.
 #