Experiment to introduce a libdatadog Ruby binding using SWIG

Rakefile

@@ -383,7 +383,11 @@ NATIVE_EXTS = [
 
   Rake::ExtensionTask.new("datadog_profiling_loader.#{RUBY_VERSION}_#{RUBY_PLATFORM}") do |ext|
     ext.ext_dir = 'ext/datadog_profiling_loader'
-  end
+  end,
+
+  Rake::ExtensionTask.new("libdatadog_ruby") do |ext|
+    ext.ext_dir = 'ext/libdatadog_ruby'
+  end,
 ].freeze
 
 NATIVE_CLEAN = ::Rake::FileList[]

datadog.gemspec

@@ -74,5 +74,5 @@ Gem::Specification.new do |spec|
   # (and yes we have a test for it)
   spec.add_dependency 'libdatadog', '~> 11.0.0.1.0'
 
-  spec.extensions = ['ext/datadog_profiling_native_extension/extconf.rb', 'ext/datadog_profiling_loader/extconf.rb']
+  spec.extensions = ['ext/datadog_profiling_native_extension/extconf.rb', 'ext/datadog_profiling_loader/extconf.rb', 'libdatadog_ruby/extconf.rb']
 end

ext/libdatadog_ruby/extconf.rb

@@ -0,0 +1,17 @@
+# rubocop:disable Style/StderrPuts
+# rubocop:disable Style/GlobalVars
+
+require 'mkmf'
+require 'libdatadog'
+
+# If we got here, libdatadog is available and loaded
+ENV['PKG_CONFIG_PATH'] = "#{ENV['PKG_CONFIG_PATH']}:#{Libdatadog.pkgconfig_folder}"
+Logging.message("[datadog] PKG_CONFIG_PATH set to #{ENV['PKG_CONFIG_PATH'].inspect}\n")
+$stderr.puts("Using libdatadog #{Libdatadog::VERSION} from #{Libdatadog.pkgconfig_folder}")
+
+unless pkg_config('datadog_profiling_with_rpath')
+  Logging.message("[datadog] Ruby detected the pkg-config command is #{$PKGCONFIG.inspect}\n")
+end
+
+create_makefile("libdatadog_ruby")
+

ext/libdatadog_ruby/generate-swig.sh

@@ -0,0 +1 @@
+swig -I/home/ivo.anjo/datadog/libdatadog/build-linux/x86_64-linux/include -ruby libdatadog.i

ext/libdatadog_ruby/libdatadog.i

@@ -0,0 +1,22 @@
+%module libdatadog_ruby
+
+%{
+  #include <datadog/common.h>
+  #include <datadog/profiling.h>
+%}
+
+%typemap(in) uintptr_t {
+  $1 = (uintptr_t) NUM2ULONG($input);
+}
+
+%typemap(in) uint64_t {
+  $1 = (uint64_t) NUM2ULONG($input);
+}
+
+%typemap(out) struct ddog_Error* {
+  ddog_CharSlice char_slice = ddog_Error_message($1);
+  $result = rb_str_new(char_slice.ptr, char_slice.len);
+}
+
+%include <datadog/common.h>
+%include <datadog/profiling.h>