Add ability to disable or force system libffi and fix stdcall on Win32

.gitmodules

@@ -1,3 +1,4 @@
 [submodule "ext/ffi_c/libffi"]
 	path = ext/ffi_c/libffi
-	url = https://github.com/libffi/libffi.git
+	url = https://github.com/larskanis/libffi.git
+	branch = fix-stdcall

Gemfile

@@ -1,7 +1,7 @@
 source 'https://rubygems.org'
 
 group :development do
-  gem 'rake', '~> 10.1'
+  gem 'rake', '~> 12.1'
   gem 'rake-compiler', '~> 1.0.3'
   gem 'rake-compiler-dock', '~> 0.7.0'
   gem 'rspec', '~> 3.0'

Rakefile

@@ -137,6 +137,7 @@ file "ext/ffi_c/libffi/autogen.sh" => "ext/ffi_c/libffi" do
   warn "Downloading libffi ..."
   sh "git submodule update --init --recursive"
 end
+task :libffi => "ext/ffi_c/libffi/autogen.sh"
 
 LIBFFI_GIT_FILES = `git --git-dir ext/ffi_c/libffi/.git ls-files -z`.split("\x0")
 

appveyor.yml

@@ -12,11 +12,16 @@ install:
   - bundle install
 build: off
 build_script:
-  - bundle exec rake compile || bundle exec rake compile
+  - bundle exec rake libffi compile -- %EXTCONFOPTS% || bundle exec rake compile -- %EXTCONFOPTS%
 test_script:
   - bundle exec rake test
 environment:
   matrix:
     - RUBYVER: "head-x64"
+      EXTCONFOPTS: "--disable-system-libffi"
     - RUBYVER: 24
+      EXTCONFOPTS: "--disable-system-libffi"
     - RUBYVER: 25-x64
+      EXTCONFOPTS: "--enable-system-libffi"
+    - RUBYVER: 25
+      EXTCONFOPTS: "--enable-system-libffi"

ext/ffi_c/extconf.rb

@@ -3,6 +3,21 @@
 if !defined?(RUBY_ENGINE) || RUBY_ENGINE == 'ruby' || RUBY_ENGINE == 'rbx'
   require 'mkmf'
   require 'rbconfig'
+
+  def system_libffi_usable?
+    # We need pkg_config or ffi.h
+    libffi_ok = pkg_config("libffi") ||
+        have_header("ffi.h") ||
+        find_header("ffi.h", "/usr/local/include", "/usr/include/ffi")
+
+    # Ensure we can link to ffi_call
+    libffi_ok &&= have_library("ffi", "ffi_call", [ "ffi.h" ]) ||
+                  have_library("libffi", "ffi_call", [ "ffi.h" ])
+
+    # And we need a libffi version recent enough to provide ffi_closure_alloc
+    libffi_ok &&= have_func("ffi_closure_alloc")
+  end
+
   dir_config("ffi_c")
 
   # recent versions of ruby add restrictive ansi and warning flags on a whim - kill them all
@@ -12,17 +27,13 @@
   # solaris 10 needs -c99 for <stdbool.h>
   $CFLAGS << " -std=c99" if RbConfig::CONFIG['host_os'] =~ /solaris(!?2\.11)/
 
-  if ENV['RUBY_CC_VERSION'].nil? && (pkg_config("libffi") ||
-     have_header("ffi.h") ||
-     find_header("ffi.h", "/usr/local/include", "/usr/include/ffi"))
-
-    # We need at least ffi_call and ffi_closure_alloc
-    libffi_ok = have_library("ffi", "ffi_call", [ "ffi.h" ]) ||
-                have_library("libffi", "ffi_call", [ "ffi.h" ])
-    libffi_ok &&= have_func("ffi_closure_alloc")
+  # Check whether we use system libffi
+  system_libffi = enable_config('system-libffi', :try)
 
-    # Check if the raw api is available.
-    $defs << "-DHAVE_RAW_API" if have_func("ffi_raw_call") && have_func("ffi_prep_raw_closure")
+  if system_libffi == :try
+    system_libffi = ENV['RUBY_CC_VERSION'].nil? && system_libffi_usable?
+  elsif system_libffi
+    abort "system libffi is not usable" unless system_libffi_usable?
   end
 
   have_header('shlwapi.h')
@@ -31,23 +42,24 @@
   have_func('rb_thread_call_with_gvl')
   have_func('rb_thread_call_without_gvl')
 
-  if libffi_ok
+  if system_libffi
     have_func('ffi_prep_cif_var')
+    $defs << "-DHAVE_RAW_API" if have_func("ffi_raw_call") && have_func("ffi_prep_raw_closure")
   else
     $defs << "-DHAVE_FFI_PREP_CIF_VAR"
+    $defs << "-DUSE_INTERNAL_LIBFFI"
   end
 
   $defs << "-DHAVE_EXTCONF_H" if $defs.empty? # needed so create_header works
-  $defs << "-DUSE_INTERNAL_LIBFFI" unless libffi_ok
   $defs << "-DRUBY_1_9" if RUBY_VERSION >= "1.9.0"
   $defs << "-DFFI_BUILDING" if RbConfig::CONFIG['host_os'] =~ /mswin/ # for compatibility with newer libffi
 
   create_header
 
-  $LOCAL_LIBS << " ./libffi/.libs/libffi_convenience.lib" if !libffi_ok && RbConfig::CONFIG['host_os'] =~ /mswin/
+  $LOCAL_LIBS << " ./libffi/.libs/libffi_convenience.lib" if !system_libffi && RbConfig::CONFIG['host_os'] =~ /mswin/
 
   create_makefile("ffi_c")
-  unless libffi_ok
+  unless system_libffi
     File.open("Makefile", "a") do |mf|
       mf.puts "LIBFFI_HOST=--host=#{RbConfig::CONFIG['host_alias']}" if RbConfig::CONFIG.has_key?("host_alias")
       if RbConfig::CONFIG['host_os'].downcase =~ /darwin/

ffi.gemspec

@@ -27,9 +27,9 @@ Gem::Specification.new do |s|
   s.license = 'BSD-3-Clause'
   s.require_paths << 'ext/ffi_c'
   s.required_ruby_version = '>= 1.9'
-  s.add_development_dependency 'rake', '~> 10.1'
+  s.add_development_dependency 'rake', '~> 12.1'
   s.add_development_dependency 'rake-compiler', '~> 1.0'
-  s.add_development_dependency 'rake-compiler-dock', '~> 0.6.2'
+  s.add_development_dependency 'rake-compiler-dock', '~> 0.7.0'
   s.add_development_dependency 'rspec', '~> 2.14.1'
   s.add_development_dependency 'rubygems-tasks', "~> 0.2.4"
 end

spec/ffi/fixtures/PipeHelperWindows.c

@@ -6,6 +6,7 @@
 
 #ifdef _WIN32
 #include <windows.h>
+#include <stdio.h>
 #include "PipeHelper.h"
 
 int pipeHelperCreatePipe(FD_TYPE pipefd[2])