Matt Aimonetti mattetti

## CGO.md

      
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                mattetti
                / CGO.md
            
            
              Created
              September 25, 2015 14:23
                — forked from dwbuiten/CGO.md
            
          
    Problems & Solutions for Interaction Between C and Go

At Vimeo, on the transcoding team, we work a lot with Go, and a lot with C, for various tasks such as media ingest. This means we use CGO quite extensively, and consequently, have run into bits that are perhaps not very well documented, if at all. Below is my effort to document some of the problems we've run into, and how we fixed or worked around them.
Many of these are obviously wrong in retrospect, but hindsight is 20/20, and these problems do exist in many codebases currently.
Some are definitely ugly, and I much welcome better solutions! Tweet me at @daemon404 if you have any, or have your own CGO story/tips, please! I'd love to learn of them.
Table of Contents

  
## gist:4983273
# First, make sure that you have the most recent rvm. Several bugs with 2.0.0-preview1 & preview 2
# have recently been fixed.
#
# Second, the openssl that comes with MacOS is too old for Ruby 2.0. You need to install
# a newer one with homebrew or the rvm pkg command.

# Option 1, with homebrew openssl:

brew update
brew install libyaml

## 0-readme.md

      
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                mattetti
                / 0-readme.md
            
            
              Created
              October 11, 2012 18:23
                — forked from burke/0-readme.md
            
          
    Ruby 1.9.3-p194 with DTrace probes, Perf Patches, and backported COW-friendly GC

Overview

This script installs a patched version of ruby 1.9.3-p194 with DTrace probes, boot-time performance improvements (#66 and #68), and runtime performance improvements (#83 and #84). It also includes the new backported GC from ruby-trunk.
Many thanks to funny-falcon for the performance patches and to Aaron Patterson for the DTrace instrumentation.

http://github.com/tenderlove/ruby/tree/probes
http://github.com/ruby/ruby/pull/66


## htmlbench.rb
require 'rubygems'
require 'nokogiri'
require 'benchmark'

text = "<html><body><h1>Mr. Belvedere Fan Club</h1></body></html>" #File.read("xmlbench.xml")
(ARGV[0] || 5).to_i.times do
  puts Benchmark.measure { 100_000.times { Nokogiri::HTML(text) }}
end

## results
$ jruby -v xmlbench.rb
jruby 1.6.5 (ruby-1.8.7-p330) (2011-10-25 9dcd388) (Java HotSpot(TM) 64-Bit Server VM 1.6.0_29) [darwin-x86_64-java]
/Users/mattetti/.rvm/gems/jruby-1.6.5/gems/nokogiri-1.5.0-java/lib/nokogiri/css.rb:3 warning: global variable `$-w' not initialized
  3.455000   0.000000   3.455000 (  3.455000)
  2.074000   0.000000   2.074000 (  2.074000)
  1.601000   0.000000   1.601000 (  1.601000)
  1.614000   0.000000   1.614000 (  1.614000)
  1.602000   0.000000   1.602000 (  1.602000)

$ ruby -v xmlbench.rb

## face_detector.rb
framework 'Cocoa'

class NSColor
  def toCGColor
    color_RGB = colorUsingColorSpaceName(NSCalibratedRGBColorSpace)
    ## approach #1
    # components = Array.new(4){Pointer.new(:double)}
    # color_RGB.getRed(components[0],
    #                 green: components[1],
    #                 blue: components[2],

## gist:1328307
module Dog
  def species
    p "I'm a dog"
  end

  def race
    p "I'm a #{self.class.name}"
  end

  # To implement in the interface implementation

## gist:1300226
ruby-1.9.2-p290 :009 > r = Record.where(:e => "x")
  Record Load (42.8ms)  SELECT "records".* FROM "records" WHERE "records"."e" = 'x'
 => []
ruby-1.9.2-p290 :010 > r.class
 => ActiveRecord::Relation
ruby-1.9.2-p290 :011 > r.where(:c => "y")
  Record Load (41.3ms)  SELECT "records".* FROM "records" WHERE "records"."e" = 'x' AND "records"."c" = 'y'
 => []
ruby-1.9.2-p290 :012 >

## StreamCampaign.rb
require 'pp'
require 'tweetstream'
require "hiredis"
require "redis/connection/hiredis"
require 'redis'


# Just so I can run without your rails stack
unless $redis
  $redis = Redis.new(:host => "127.0.0.1", :port => 6379)

## benchmark.rb
#!/usr/bin/env ruby
require 'benchmark'

require 'rubygems'
gem 'therubyracer'
gem 'haml'
gem 'tilt'

require 'v8'
require 'haml'
	# First, make sure that you have the most recent rvm. Several bugs with 2.0.0-preview1 & preview 2
	# have recently been fixed.
	#
	# Second, the openssl that comes with MacOS is too old for Ruby 2.0. You need to install
	# a newer one with homebrew or the rvm pkg command.

	# Option 1, with homebrew openssl:

	brew update
	brew install libyaml
	require 'rubygems'
	require 'nokogiri'
	require 'benchmark'

	text = "<html><body><h1>Mr. Belvedere Fan Club</h1></body></html>" #File.read("xmlbench.xml")
	(ARGV[0] \|\| 5).to_i.times do
	puts Benchmark.measure { 100_000.times { Nokogiri::HTML(text) }}
	end
	$ jruby -v xmlbench.rb
	jruby 1.6.5 (ruby-1.8.7-p330) (2011-10-25 9dcd388) (Java HotSpot(TM) 64-Bit Server VM 1.6.0_29) [darwin-x86_64-java]
	/Users/mattetti/.rvm/gems/jruby-1.6.5/gems/nokogiri-1.5.0-java/lib/nokogiri/css.rb:3 warning: global variable `$-w' not initialized
	3.455000 0.000000 3.455000 ( 3.455000)
	2.074000 0.000000 2.074000 ( 2.074000)
	1.601000 0.000000 1.601000 ( 1.601000)
	1.614000 0.000000 1.614000 ( 1.614000)
	1.602000 0.000000 1.602000 ( 1.602000)

	$ ruby -v xmlbench.rb
	framework 'Cocoa'

	class NSColor
	def toCGColor
	color_RGB = colorUsingColorSpaceName(NSCalibratedRGBColorSpace)
	## approach #1
	# components = Array.new(4){Pointer.new(:double)}
	# color_RGB.getRed(components[0],
	# green: components[1],
	# blue: components[2],
	module Dog
	def species
	p "I'm a dog"
	end

	def race
	p "I'm a #{self.class.name}"
	end

	# To implement in the interface implementation
	ruby-1.9.2-p290 :009 > r = Record.where(:e => "x")
	Record Load (42.8ms) SELECT "records".* FROM "records" WHERE "records"."e" = 'x'
	=> []
	ruby-1.9.2-p290 :010 > r.class
	=> ActiveRecord::Relation
	ruby-1.9.2-p290 :011 > r.where(:c => "y")
	Record Load (41.3ms) SELECT "records".* FROM "records" WHERE "records"."e" = 'x' AND "records"."c" = 'y'
	=> []
	ruby-1.9.2-p290 :012 >
	require 'pp'
	require 'tweetstream'
	require "hiredis"
	require "redis/connection/hiredis"
	require 'redis'


	# Just so I can run without your rails stack
	unless $redis
	$redis = Redis.new(:host => "127.0.0.1", :port => 6379)
	#!/usr/bin/env ruby
	require 'benchmark'

	require 'rubygems'
	gem 'therubyracer'
	gem 'haml'
	gem 'tilt'

	require 'v8'
	require 'haml'