add native dlopen extension code

This will get dlopen in a consistent place on all the platforms
which need it.

Rakefile

@@ -51,6 +51,13 @@ Rake::ExtensionTask.new do |ext|
   ext.gem_spec = spec
 end
 
+Rake::ExtensionTask.new do |ext|
+  ext.name = 'dlopen'
+  ext.lib_dir = 'lib/ffi_yajl/ext'
+  ext.ext_dir = 'ext/ffi_yajl/ext/dlopen'
+  ext.gem_spec = spec
+end
+
 #
 # test tasks
 #

ext/ffi_yajl/ext/dlopen/dlopen.c

@@ -0,0 +1,38 @@
+#include <ruby.h>
+
+#if defined(HAVE_DLFCN_H)
+# include <dlfcn.h>
+#ifndef RTLD_LAZY
+#define RTLD_LAZY 0
+#endif
+#ifndef RTLD_GLOBAL
+#define RTLD_GLOBAL 0
+#endif
+#ifndef RTLD_NOW
+#define RTLD_NOW 0
+#endif
+#else
+# if defined(_WIN32)
+#   include <windows.h>
+#   define dlopen(name,flag) ((void*)LoadLibrary(name))
+#   define dlerror() strerror(rb_w32_map_errno(GetLastError()))
+#   define dlsym(handle,name) ((void*)GetProcAddress((handle),(name)))
+#   define RTLD_LAZY -1
+#   define RTLD_NOW  -1
+#   define RTLD_GLOBAL -1
+# endif
+#endif
+
+static VALUE mFFI_Yajl, mDlopen, mExt;
+
+static VALUE mDlopen_dlopen(VALUE self, VALUE file) {
+  dlopen(RSTRING_PTR(file), RTLD_NOW|RTLD_GLOBAL);
+  return Qnil;
+}
+
+void Init_dlopen() {
+  mFFI_Yajl = rb_define_module("FFI_Yajl");
+  mExt = rb_define_module_under(mFFI_Yajl, "Ext");
+  mDlopen = rb_define_module_under(mExt, "Dlopen");
+  rb_define_method(mDlopen, "dlopen", mDlopen_dlopen, 1);
+}

ext/ffi_yajl/ext/dlopen/extconf.rb

@@ -0,0 +1,15 @@
+require 'mkmf'
+require 'rubygems'
+
+RbConfig::MAKEFILE_CONFIG['CC'] = ENV['CC'] if ENV['CC']
+
+puts $CFLAGS
+puts $LDFLAGS
+
+have_header("dlfcn.h")
+
+have_library("dl", "dlopen")
+
+dir_config 'dlopen'
+
+create_makefile 'ffi_yajl/ext/dlopen'

ffi-yajl.gemspec

@@ -1,7 +1,6 @@
 gemspec = eval(IO.read(File.expand_path(File.join(File.dirname(__FILE__), "ffi-yajl.gemspec.shared"))))
 
 gemspec.platform = Gem::Platform::RUBY
-gemspec.extensions = %w{ ext/ffi_yajl/ext/encoder/extconf.rb ext/ffi_yajl/ext/parser/extconf.rb }
+gemspec.extensions = %w{ ext/ffi_yajl/ext/encoder/extconf.rb ext/ffi_yajl/ext/parser/extconf.rb ext/ffi_yajl/ext/dlopen/extconf.rb }
 
 gemspec
-

lib/ffi_yajl.rb

@@ -19,10 +19,10 @@
   require 'ffi_yajl/ffi'
 elsif RUBY_PLATFORM == "java"
   require 'ffi_yajl/ffi'
-elsif defined?(Yajl)
-  warn "the ffi-yajl and yajl-ruby gems have incompatible C libyajl libs and should not be loaded in the same Ruby VM"
-  warn "falling back to ffi which might work (or might not, no promises)"
-  require 'ffi_yajl/ffi'
+#elsif defined?(Yajl)
+#  warn "the ffi-yajl and yajl-ruby gems have incompatible C libyajl libs and should not be loaded in the same Ruby VM"
+#  warn "falling back to ffi which might work (or might not, no promises)"
+#  require 'ffi_yajl/ffi'
 else
   begin
     require 'ffi_yajl/ext'

lib/ffi_yajl/ext.rb

@@ -4,60 +4,17 @@
 require 'ffi_yajl/parser'
 require 'libyajl2'
 require 'ffi_yajl/map_library_name'
+require 'ffi_yajl/ext/dlopen'
 
 module FFI_Yajl
   extend FFI_Yajl::MapLibraryName
 
+  extend FFI_Yajl::Ext::Dlopen
+
   libname = map_library_name
   libpath = File.expand_path(File.join(Libyajl2.opt_path, libname))
 
-  #
-  # FFS, what exactly was so wrong with DL.dlopen that ruby had to get rid of it???
-  #
-
-  def self.try_fiddle_dlopen(libpath)
-    require 'fiddle'
-    if defined?(Fiddle) && Fiddle.respond_to?(:dlopen)
-      ::Fiddle.dlopen(libpath)
-      true
-    else
-      false
-    end
-  rescue LoadError
-    return false
-  end
-
-  def self.try_dl_dlopen(libpath)
-    require 'dl'
-    if defined?(DL) && DL.respond_to?(:dlopen)
-      ::DL.dlopen(libpath)
-      true
-    else
-      false
-    end
-  rescue LoadError
-    return false
-  end
-
-  def self.try_ffi_dlopen(libpath)
-    require 'ffi'
-    require 'rbconfig'
-    extend ::FFI::Library
-    ffi_lib 'dl'
-    attach_function 'dlopen', :dlopen, [:string, :int], :void
-    if  RbConfig::CONFIG['host_os'] =~ /linux/i
-      dlopen libpath, 0x102  # linux: RTLD_GLOBAL | RTLD_NOW
-    else
-      dlopen libpath, 0
-    end
-    true
-  rescue LoadError
-    return false
-  end
-
-  unless try_fiddle_dlopen(libpath) || try_dl_dlopen(libpath) || try_ffi_dlopen(libpath)
-    raise "cannot find dlopen via Fiddle, DL or FFI, what am I supposed to do?"
-  end
+  dlopen(libpath)
 
   class Parser
     require 'ffi_yajl/ext/parser'