Native Extensions Served 3 Ways

Native Extensions Served 3 Ways

This talk was given at Garden City Ruby Conf 2014

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Tejas Dinkar

January 03, 2014
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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
  6. None
  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