added --dontwait and --restart options

README.md

@@ -84,6 +84,13 @@ filesystem gets updated:
 
     $ filewatcher "src test" "ruby test/test_suite.rb"
 
+Automatic restart of processes
+------------------------------
+
+The `--restart` option restarts the command when changes happens on the file system. The `--dontwait` starts the command when filewatcher is started. To start a webserver and have it automatically restart when html files are updated:
+
+    $ filewatcher --dontwait --restart "*.html" "python -m SimpleHTTPServer"
+
 Available enviroment variables
 ------------------------------
 
@@ -209,4 +216,4 @@ Note on Patches/Pull Requests
 Copyright
 ---------
 
-Copyright (c) 2011 - 2014 Thomas Flemming. See LICENSE for details.
+Copyright (c) 2011 - 2015 Thomas Flemming. See LICENSE for details.

Rakefile

@@ -3,6 +3,8 @@ require 'rake'
 require 'rake/testtask'
 
 task :default => :test
+
+desc "Run tests"
 task :test do
   sh "bacon -Ilib -Itest --automatic --quiet"
 end

bin/filewatcher

@@ -3,9 +3,10 @@ require 'rubygems'
 require 'filewatcher'
 require 'trollop'
 require 'pathname'
+require 'thread'
 
 options = Trollop::options do
-  version "filewatcher, version #{FileWatcher.VERSION} by Thomas Flemming 2014"
+  version "filewatcher, version #{FileWatcher.VERSION} by Thomas Flemming 2015"
   banner <<-EOS
 Filewatcher scans the filesystem and executes shell commands when files changes.
 
@@ -22,11 +23,13 @@ Examples:
 Options:
 EOS
 
-  opt :interval, "Interval to scan filesystem. Defaults to 0.5 seconds.", :short => 'i', :type => :float, :default => 0.5
+  opt :dontwait, "Do not wait for filesystem updates before running", :short => 'd', :type => :boolean, :default => false
+  opt :restart, "Restart process when filesystem is updated", :short => 'r', :type => :boolean, :default => false
+  opt :list, "Print name of files being watched"
   opt :exec, "Execute file as a script when file is updated.", :short => 'e', :type => :boolean, :default => false
   opt :include, "Include files", :type => :string, :default => "*"
   opt :exclude, "Exclude file(s) matching", :type => :string, :default => ""
-  opt :list, "Print name of files being watched"
+  opt :interval, "Interval to scan filesystem. Defaults to 0.5 seconds.", :short => 'i', :type => :float, :default => 0.5  
 end
 
 Trollop::die "must have at least one argument" if(ARGV.size == 0)
@@ -56,7 +59,45 @@ end
 
 files = split_files_void_escaped_whitespace(files)
 
-FileWatcher.new(files, options[:list]).watch(options[:interval]) do |filename, event|
+def fork_process(env, cmd)
+  pipe_read, pipe_write = IO.pipe
+  fork do
+    pipe_read.close
+    pipe_write.write Process.spawn(env,cmd).to_s
+    exit
+  end
+
+  Kernel.sleep 1
+  pipe_write.close
+  child_pid = pipe_read.read.to_i
+  pipe_read.close
+  return child_pid
+end
+
+def kill_process(child_pid)
+  still_running = true
+  begin
+    Process.kill(1, child_pid)
+  rescue Errno::ESRCH
+    still_running = false
+  end
+  while still_running do
+    begin
+      Process.getpgid( child_pid)
+      still_running = true
+    rescue Errno::ESRCH
+      still_running = false
+    end
+    Kernel.sleep 0.1
+  end
+end
+
+if(options[:restart])
+  rd, wr = IO.pipe
+  child_pid = nil
+end
+
+FileWatcher.new(files, options[:list], options[:dontwait]).watch(options[:interval]) do |filename, event|
   cmd = nil
   if(options[:exec] and File.exist?(filename))
     extension = filename[/(\.[^\.]*)$/,0]
@@ -91,8 +132,23 @@ FileWatcher.new(files, options[:list]).watch(options[:interval]) do |filename, e
     if(event != :delete)
       ENV['FILEPATH'] = path.realpath.to_s
     end
-    pid = Process.spawn(env, cmd);
-    pid = Process.wait();
+
+    if(options[:restart])
+      if(child_pid == nil)
+        child_pid = fork_process(env, cmd)
+      else
+        kill_process(child_pid)
+        child_pid = fork_process(env, cmd)
+      end
+    else
+      begin
+        pid = Process.spawn(env, cmd)
+        Process.wait()
+      rescue SystemExit, Interrupt
+        exit(0)
+      end
+    end
+
   else
     case(event)
     when :changed

lib/filewatcher.rb

@@ -6,14 +6,14 @@ class FileWatcher
   attr_accessor :filenames
 
   def self.VERSION
-    return '0.3.6'
+    return '0.4.0'
   end
 
-  def initialize(unexpanded_filenames, print_filelist=false)
+  def initialize(unexpanded_filenames, print_filelist=false, dontwait=false)
     @unexpanded_filenames = unexpanded_filenames
     @last_mtimes = { }
     @filenames = expand_directories(@unexpanded_filenames)
-
+    @dontwait = dontwait
     puts 'Watching:' if print_filelist
     @filenames.each do |filename|
       raise 'File does not exist' unless File.exist?(filename)
@@ -23,6 +23,9 @@ def initialize(unexpanded_filenames, print_filelist=false)
   end
 
   def watch(sleep=1, &on_update)
+    if(@dontwait)
+      yield '',''
+    end
     loop do
       begin
         Kernel.sleep sleep until filesystem_updated?