Adding stream mode.

The mode is the first option for the FSEvents::Stream object itself (and not the OSX FSEvent stream). It will primarily affect the strategy for getting an event's modified files.

lib/fsevents/stream.rb

@@ -2,18 +2,23 @@
 
 module FSEvents
   class Stream
-    attr_reader :stream, :last_event
+    attr_reader :stream, :mode, :last_event
     attr_reader :allocator, :context, :paths, :since, :latency, :flags, :callback
 
     class StreamError < StandardError; end
 
+    MODES = [:mtime, :cache]
+
     def initialize(*paths, &callback)
       raise ArgumentError, 'A callback block is required' if callback.nil?
       @callback = callback
 
       options = {}
       options = paths.pop if paths.last.is_a?(Hash)
 
+      @mode = options[:mode] || :mtime
+      raise ArgumentError, "Mode '#{mode}' unknown" unless MODES.include?(@mode)
+
       paths = Dir.pwd if paths.empty?
 
       @allocator = options[:allocator] || OSX::KCFAllocatorDefault

spec/stream_spec.rb

@@ -50,6 +50,7 @@
         [:allocator, :context, :since, :latency, :flags].each do |opt|
           @options[opt] = stub(opt.to_s)
         end
+        @options[:mode] = :cache
         @other_path = '/other/path'
       end
 
@@ -113,6 +114,19 @@
         @options.delete(:flags)
         FSEvents::Stream.new(@path, @options) {}.flags.should == 0
       end
+
+      it 'should store mode' do
+        FSEvents::Stream.new(@path, @options) {}.mode.should == @options[:mode]
+      end
+
+      it 'should default mode to mtime' do
+        @options.delete(:mode)
+        FSEvents::Stream.new(@path, @options) {}.mode.should == :mtime
+      end
+
+      it 'should not accept any mode other than mtime or cache' do
+        lambda { FSEvents::Stream.new(@path, @options.merge(:mode => :something_else)) {} }.should raise_error(ArgumentError)
+      end
     end
   end