Autotest fsevent ffi.c

#include <CoreServices/CoreServices.h>

static void callback(ConstFSEventStreamRef streamRef,
					 void *clientCallBackInfo,
					 size_t numEvents,
					 void *eventPaths,
					 const FSEventStreamEventFlags eventFlags[],
					 const FSEventStreamEventId eventIds[]) {
	exit(0);
}

static int sleep_until_change(const char * path){
	// Create event stream
	CFStringRef pathToWatch = CFStringCreateWithCString(kCFAllocatorDefault, path, kCFStringEncodingUTF8);
    CFArrayRef pathsToWatch = CFArrayCreate(NULL, (const void **)&pathToWatch, 1, NULL);	
    void *callbackInfo = NULL;
    FSEventStreamRef stream;
    CFAbsoluteTime latency = 1.0;
    stream = FSEventStreamCreate(
								 kCFAllocatorDefault,
								 callback,
								 callbackInfo,
								 pathsToWatch,
								 kFSEventStreamEventIdSinceNow,
								 latency,
								 kFSEventStreamCreateFlagNone
								 );
	
	// Add stream to run loop
    FSEventStreamScheduleWithRunLoop(stream, CFRunLoopGetCurrent(), kCFRunLoopDefaultMode);
	FSEventStreamStart(stream);
	CFRunLoopRun();
	
	// Exit
	return 2;
}

Compilation

`CFLAGS='-isysroot /Developer/SDKs/MacOSX#{SDK_VERSION}.sdk -mmacosx-version-min=#{SDK_VERSION}' /usr/bin/gcc -c fsevent_sleep.c -o "#{GEM_ROOT}/bin/fsevent_sleep.so"`

gistfile2.rb

module Autotest::FSEvent

	GEM_PATH = File.expand_path(File.join(File.dirname(__FILE__), '..', '..')) unless defined?(GEM_PATH)
	extend FFI::Library
	
        ffi_lib "/Users/fonsan/Projects/autotest-fsevent/bin/fsevent_sleep.so"
	

	##
	# Use FSEvent if possible 
	# Add waiting hook to prevent fallback to polling after ignored files have changed
	Autotest.add_hook :initialize do
		if Uname.sysname == 'Darwin' && Uname.release.to_i >= 9
			class ::Autotest
			  remove_method :wait_for_changes
				def wait_for_changes
					hook :waiting
					begin
						`cd '#{Dir.pwd}'; #{File.join(GEM_PATH, 'bin', 'fsevent_sleep')} . 2>&1`
						Kernel.sleep self.sleep
					end until find_files_to_test
				end
			end
		else
			puts
			puts "autotest-fsevent: platform #{Uname.sysname} #{Uname.release} is not supported"
		end
	end

end

output

/Users/fonsan/.rvm/gems/ruby-1.9.2-p180@autotest-fsevent/gems/ffi-1.0.6/lib/ffi/library.rb:75:in `block in ffi_lib': Could not open library '/Users/fonsan/Projects/autotest-fsevent/bin/fsevent_sleep.so': dlopen(/Users/fonsan/Projects/autotest-fsevent/bin/fsevent_sleep.so, 5): no suitable image found.  Did find: (LoadError)
	/Users/fonsan/Projects/autotest-fsevent/bin/fsevent_sleep.so: file too short
	from /Users/fonsan/.rvm/gems/ruby-1.9.2-p180@autotest-fsevent/gems/ffi-1.0.6/lib/ffi/library.rb:54:in `map'