Experimentations with node-ffi

objc.js

var ffi = require('node-ffi')
  , objc = new ffi.Library(null, {
      'objc_getClass': [ 'pointer', [ 'string' ] ]
    , 'class_getName': [ 'string', [ 'pointer' ] ]
    , 'sel_registerName': [ 'pointer', [ 'string' ] ]
    , 'sel_getName': [ 'string', [ 'pointer' ] ]
    , 'objc_msgSend': [ 'pointer', [ 'pointer', 'pointer' ] ]
  })
  // The problem with libffi and C functions that accepts varargs is that we
  // have to create new wrappers for each different argument and return value
  // signature that we encounter
  , objc1 = new ffi.Library(null, {
      'objc_msgSend': [ 'pointer', [ 'pointer', 'pointer', 'int32' ] ]
  })
  , objc2 = new ffi.Library(null, {
      'objc_msgSend': [ 'string', [ 'pointer', 'pointer' ] ]
  })
  , objc3 = new ffi.Library(null, {
      'objc_msgSend': [ 'pointer', [ 'pointer', 'pointer', 'pointer' ] ]
  })
  , objc4 = new ffi.Library(null, {
      'objc_msgSend': [ 'pointer', [ 'pointer', 'pointer', 'string' ] ]
  })
  , getClass = objc.objc_getClass

// dlopen equivalent
new ffi.DynamicLibrary('/System/Library/Frameworks/Foundation.framework/Foundation');
new ffi.DynamicLibrary('/System/Library/Frameworks/ScriptingBridge.framework/ScriptingBridge');

function $C (v) {
  return getClass(v);
}
function $R (v) {
  return objc.sel_registerName(v);
}
function $D (v) {
  return objc2.objc_msgSend(objc.objc_msgSend(v, description), objc.sel_registerName('UTF8String'));
}

var NSAP = $C('NSAutoreleasePool')
  , alloc = $R('alloc')
  , init = $R('init')
  , pool = objc.objc_msgSend(objc.objc_msgSend(NSAP, alloc), init);

var NSArray = $C('NSMutableArray');
console.log(NSArray.address);
console.log(objc.class_getName(NSArray));

var NSString = $C('NSString')
  , stringWithUTF8String = $R('stringWithUTF8String:')
  , str = objc4.objc_msgSend(NSString, stringWithUTF8String, 'Hello Objective-C!')
  , description = $R('description')
console.log($D(str));

var initWithCapacity = $R('initWithCapacity:')
  , addObject = $R('addObject:')
console.log(objc.sel_getName(alloc));

var array = objc.objc_msgSend(NSArray, alloc);
array = objc1.objc_msgSend(array, init, 10);

objc3.objc_msgSend(array, addObject, NSArray);
objc3.objc_msgSend(array, addObject, str);
console.log($D(array));

// Normally this wouldn't work properly. However we have dynamically loaded the
// ScriptingBridge framework binary file above so this will work properly.
var SBApplication = objc.objc_getClass('SBApplication');
console.log(SBApplication.address);
console.log(objc.class_getName(SBApplication));

printf.js

var ffi = require('node-ffi')
  , stdio = new ffi.Library(null, {
      'printf': [ 'int32', [ 'string', 'string' ]]
  })

stdio.printf('hello %s\n', 'world');
// hello world

time.js

var ffi = require('node-ffi')
  , time = new ffi.Library(null, {
      'time': [ 'int32', [ 'pointer' ] ]
  })
  , NULL = new ffi.Pointer(0)

// Passing JS null converts to C NULL
console.log(time.time(null));

// new ffi.Pointer(0) creates a NULL pointer
console.log(time.time(NULL));

var time_t = new ffi.Pointer(4);
console.log(time.time(time_t));
console.log(time_t.getInt32());