Native Extensions Served 3 Ways

This talk was given at Garden City Ruby Conf 2014

Transcript

1. Native Extensions Served 3 Ways Tejas Dinkar Nilenso Software
2. about.me • Hi, I’m Tejas • Nilenso: Partner • twitter: tdinkar • github: gja
3. about.talk • Expect to see lots of code • Will have about 5 minutes for questions • Please laugh at my jokes! • Will cover C Extensions, FFI and SWIG
4. Native Extensions • Integrate with new libraries • Improve Performance of critical code • Write code that works across languages • Feel super 1337
5. Let’s talk about Python • Pythonista’s in the house? • Yes, I’m trolling you! http://montgomeryq.blogspot.in/2011/05/random-illustration-tuesday-python-ruby.html
7. #include "Python.h" #include "ruby.h" ! static PyObject *python_ruby_eval(PyObject *self, PyObject *string) { VALUE val = rb_eval_string(PyString_AsString(string)); switch(TYPE(val)) { case T_FIXNUM: return PyInt_FromLong(FIX2INT(val)); case T_STRING: return PyString_FromString(StringValuePtr(val)); default: return Py_None; // Can handle these cases later } } ! static PyMethodDef module_functions[] = { { "eval", python_ruby_eval, METH_O, "Evaluate Ruby Code" }, { NULL } }; ! void initruby(void) { ruby_init(); Py_InitModule3("ruby", module_functions, "A ruby module for python."); }
8. #include "Python.h" #include "ruby.h" ! static PyObject *python_ruby_eval(PyObject *self, PyObject *string) { VALUE val = rb_eval_string(PyString_AsString(string)); switch(TYPE(val)) { case T_FIXNUM: return PyInt_FromLong(FIX2INT(val)); case T_STRING: return PyString_FromString(StringValuePtr(val)); default: return Py_None; // Can handle these cases later } } ! static PyMethodDef module_functions[] = { { "eval", python_ruby_eval, METH_O, "Evaluate Ruby Code" }, { NULL } }; ! void initruby(void) { ruby_init(); Py_InitModule3("ruby", module_functions, "A ruby module for python."); }
9. #include "Python.h" #include "ruby.h" ! static PyObject *python_ruby_eval(PyObject *self, PyObject *string) { VALUE val = rb_eval_string(PyString_AsString(string)); switch(TYPE(val)) { case T_FIXNUM: return PyInt_FromLong(FIX2INT(val)); case T_STRING: return PyString_FromString(StringValuePtr(val)); default: return Py_None; // Can handle these cases later } } ! static PyMethodDef module_functions[] = { { "eval", python_ruby_eval, METH_O, "Evaluate Ruby Code" }, { NULL } }; ! void initruby(void) { ruby_init(); Py_InitModule3("ruby", module_functions, "A ruby module for python."); }
10. #include "Python.h" #include "ruby.h" ! static PyObject *python_ruby_eval(PyObject *self, PyObject *string) { VALUE val = rb_eval_string(PyString_AsString(string)); switch(TYPE(val)) { case T_FIXNUM: return PyInt_FromLong(FIX2INT(val)); case T_STRING: return PyString_FromString(StringValuePtr(val)); default: return Py_None; // Can handle these cases later } } ! static PyMethodDef module_functions[] = { { "eval", python_ruby_eval, METH_O, "Evaluate Ruby Code" }, { NULL } }; ! void initruby(void) { ruby_init(); Py_InitModule3("ruby", module_functions, "A ruby module for python."); }
11. #include "Python.h" #include "ruby.h" ! static PyObject *python_ruby_eval(PyObject *self, PyObject *string) { VALUE val = rb_eval_string(PyString_AsString(string)); switch(TYPE(val)) { case T_FIXNUM: return PyInt_FromLong(FIX2INT(val)); case T_STRING: return PyString_FromString(StringValuePtr(val)); default: return Py_None; // Can handle these cases later } } ! static PyMethodDef module_functions[] = { { "eval", python_ruby_eval, METH_O, "Evaluate Ruby Code" }, { NULL } }; ! void initruby(void) { ruby_init(); Py_InitModule3("ruby", module_functions, "A ruby module for python."); }
12. #include "Python.h" #include "ruby.h" ! static PyObject *python_ruby_eval(PyObject *self, PyObject *string) { VALUE val = rb_eval_string(PyString_AsString(string)); switch(TYPE(val)) { case T_FIXNUM: return PyInt_FromLong(FIX2INT(val)); case T_STRING: return PyString_FromString(StringValuePtr(val)); default: return Py_None; // Can handle these cases later } } ! static PyMethodDef module_functions[] = { { "eval", python_ruby_eval, METH_O, "Evaluate Ruby Code" }, { NULL } }; ! void initruby(void) { ruby_init(); Py_InitModule3("ruby", module_functions, "A ruby module for python."); }
13. #include "Python.h" #include "ruby.h" ! static PyObject *python_ruby_eval(PyObject *self, PyObject *string) { VALUE val = rb_eval_string(PyString_AsString(string)); switch(TYPE(val)) { case T_FIXNUM: return PyInt_FromLong(FIX2INT(val)); case T_STRING: return PyString_FromString(StringValuePtr(val)); default: return Py_None; // Can handle these cases later } } ! static PyMethodDef module_functions[] = { { "eval", python_ruby_eval, METH_O, "Evaluate Ruby Code" }, { NULL } }; ! void initruby(void) { ruby_init(); Py_InitModule3("ruby", module_functions, "A ruby module for python."); }
14. #include "Python.h" #include "ruby.h" ! static PyObject *python_ruby_eval(PyObject *self, PyObject *string) { VALUE val = rb_eval_string(PyString_AsString(string)); switch(TYPE(val)) { case T_FIXNUM: return PyInt_FromLong(FIX2INT(val)); case T_STRING: return PyString_FromString(StringValuePtr(val)); default: return Py_None; // Can handle these cases later } } ! static PyMethodDef module_functions[] = { { "eval", python_ruby_eval, METH_O, "Evaluate Ruby Code" }, { NULL } }; ! void initruby(void) { ruby_init(); Py_InitModule3("ruby", module_functions, "A ruby module for python."); }
15. Require Files? static PyObject *python_ruby_require(PyObject *self, PyObject *file) { rb_require(PyString_AsString(file)); return Py_True; }
16. Congrats!
17. Common Fears MEMORY ALLOCATION!?
18. Memory Management • Data_Wrap_Struct(klass, mark_cb, free_cb, *data) • Data_Get_Struct( VALUE, data_type, data* )
19. Common Fears
20. Portability http://geekandpoke.typepad.com/geekandpoke/2008/05/the-history-of.html
21. void Init_String(void) {! rb_cString = rb_define_class("String", rb_cObject);! // ...! rb_define_method(rb_cString, "eql?", rb_str_eql, 1);! rb_define_method(rb_cString, "==", rb_str_equal, 1);! // ...! rb_define_method(rb_cString, "insert", rb_str_insert, 2);! rb_define_method(rb_cString, "length", rb_str_length, 0);! // ...! }! ! static VALUE rb_str_eql(VALUE self, VALUE str2)! {! if (self == str2) return Qtrue;! if (!RB_TYPE_P(str2, T_STRING)) return Qfalse;! return str_eql(self, str2);! }! string.c
22. void Init_String(void) {! rb_cString = rb_define_class("String", rb_cObject);! // ...! rb_define_method(rb_cString, "eql?", rb_str_eql, 1);! rb_define_method(rb_cString, "==", rb_str_equal, 1);! // ...! rb_define_method(rb_cString, "insert", rb_str_insert, 2);! rb_define_method(rb_cString, "length", rb_str_length, 0);! // ...! }! ! static VALUE rb_str_eql(VALUE str2, VALUE str2)! {! if (self == str2) return Qtrue;! if (!RB_TYPE_P(str2, T_STRING)) return Qfalse;! return str_eql(self, str2);! }! string.c
23. void Init_String(void) {! rb_cString = rb_define_class("String", rb_cObject);! // ...! rb_define_method(rb_cString, "eql?", rb_str_eql, 1);! rb_define_method(rb_cString, "==", rb_str_equal, 1);! // ...! rb_define_method(rb_cString, "insert", rb_str_insert, 2);! rb_define_method(rb_cString, "length", rb_str_length, 0);! // ...! }! ! static VALUE rb_str_eql(VALUE str2, VALUE str2)! {! if (self == str2) return Qtrue;! if (!RB_TYPE_P(str2, T_STRING)) return Qfalse;! return str_eql(self, str2);! }! string.c
24. C Extensions Native Code Ruby Code Ruby Aware! Native Code
25. Foreign Function Interface Native Code Ruby Code Native Aware! Ruby Code
26. Foreign Function Interface • A Ruby DSL • Works across all Ruby Implementations • Converts to and from C primitives for you
27. example require 'ffi'! ! module MyLib! extend FFI::Library! ffi_lib 'c'! attach_function :puts, [:string], :int! end! ! MyLib.puts 'Hello, World using libc!'
28. another example require 'ffi'! ! module MyMathLib! extend FFI::Library! ffi_lib 'm'! attach_function :pow, [:double, :double],! :double! end! ! MyMathLib.pow(4, 5) # => 1024.0
29. Lots of built in types Numbers!! ! ! ! ! Character!! ! ! ! ! Other! :int! ! ! ! ! ! ! :char!! ! ! ! ! ! ! :pointer! :short! ! ! ! ! ! :string! :long! :double! :float!
30. Foreign Function Interface • Probably your best solution • It’s really easy • Do your modelling in Ruby • Still have to worry about GC • Sadly, no C++ without wrapping
31. Memory in FFI def run_query_which_will_crash! db_connection = MyFFIModule.database_connection("localhost")! MyFFIModule.database_query(db_connection, "select * from users")! end!
32. Memory in FFI def run_query_which_will_crash! db_connection = MyFFIModule.database_connection("localhost")! MyFFIModule.database_query(db_connection, "select * from users")! end! This will get GCed
33. SWIG • Simplified Wrapper and Interface Generator • Annotate your C/C++ header files • It generates native extensions for languages • About 20 languages currently supported
34. SWIG Native Code Ruby Code Magic Python Code
35. The Magic • Takes an interface file • Auto generates code to make it work • For ruby, it’s a `regular’ C extension • For python, it’s a a .c and .py file • For Java it’s a JNI interface • Still need to do your own GC
36. The Rectangle class Rectangle! {! int length;! int breadth;! ! public:! Rectangle(int length, int breadth);! int area();! };
37. The Rectangle class Rectangle! {! int length;! int breadth;! ! public:! Rectangle(int length, int breadth);! int area();! }; #ifdef SWIG %module shape %{ %} SWIG Stuff Here
38. require 'shapes'! ! rectangle = shapes.Rectangle.new(10, 12)! rectangle.area == 120!
39. Other Options • DL (Dynamic Load) • Fiddle(r)
40. TL;DR • Native Extensions are fun and easy to build • The three big tools • You want to pick FFI if you don’t maintain the lib • SWIG may be better if you are a maintainer
41. Thank You Many Questions? wow so native so extension wow no python such easy such performance super integration ruby = win