Remove ffi gem as a hard dependency

Copies the algorithm out of FFI.map_library_name into the
FFI_Yajl#map_library_name function so that when we're loading up the
C extension we don't need to also slurp in the ffi gem just to run
that.  The ffi gem is moved to a hard dependency of only the jruby
version of the gem, and its a development dependency for the other
ruby VMs (so rake spec will work against the ffi library), but its
an optional library to install to make the ffi library work on VMs
that support C extensions (MRI, RBX).

3 files changed, 52 insertions, 16 deletions

diff --git a/lib/ffi_yajl/ext.rb b/lib/ffi_yajl/ext.rb
index 5784023..bc4d410 100644
--- a/lib/ffi_yajl/ext.rb
+++ b/lib/ffi_yajl/ext.rb
@@ -2,22 +2,14 @@ require 'rubygems'
 
 require 'ffi_yajl/encoder'
 require 'ffi_yajl/parser'
-require 'ffi'
 require 'libyajl2'
-require 'ffi_yajl/platform'
+require 'ffi_yajl/map_library_name'
 
 module FFI_Yajl
-  extend FFI_Yajl::Platform
+  extend FFI_Yajl::MapLibraryName
 
-  # FIXME: DRY with ffi_yajl/ffi.rb
-  # FIXME: extract map_library_name from FFI and stop requiring it at the top level
-  #        so that the C-library can be installed without FFI
-  libname = ::FFI.map_library_name("yajl")
-  # awful windows patch, but there is an open issue to entirely replace FFI.map_library_name already
-  libname = "libyajl.so" if windows?
+  libname = map_library_name
   libpath = File.expand_path(File.join(Libyajl2.opt_path, libname))
-  libpath.gsub!(/dylib/, 'bundle')
-  libpath = ::FFI.map_library_name("yajl") unless File.exist?(libpath)
 
   #
   # FFS, what exactly was so wrong with DL.dlopen that ruby had to get rid of it???
diff --git a/lib/ffi_yajl/ffi.rb b/lib/ffi_yajl/ffi.rb
index 4e685a6..e291ba5 100644
--- a/lib/ffi_yajl/ffi.rb
+++ b/lib/ffi_yajl/ffi.rb
@@ -1,16 +1,23 @@
 require 'rubygems'
 
 require 'libyajl2'
-require 'ffi'
+begin
+  require 'ffi'
+rescue LoadError
+  puts "FATAL: to use the ffi extension instead of the compiled C extension, the ffi gem must be installed"
+  puts "       (it is optional, so you must include it in your bundle manually)"
+  exit 1
+end
+
+require 'ffi_yajl/map_library_name'
 
 module FFI_Yajl
   extend ::FFI::Library
 
-  libname = ::FFI.map_library_name("yajl")
-  # XXX: need to replace ::FFI.map_library_name here as well
-  libname = "libyajl.so" if libname == "yajl.dll"
+  extend FFI_Yajl::MapLibraryName
+
+  libname = map_library_name
   libpath = File.expand_path(File.join(Libyajl2.opt_path, libname))
-  libpath.gsub!(/dylib/, 'bundle')
 
   if File.file?(libpath)
     # use our vendored version of libyajl2 if we find it installed
diff --git a/lib/ffi_yajl/map_library_name.rb b/lib/ffi_yajl/map_library_name.rb
new file mode 100644
index 0000000..3518d07
--- /dev/null
+++ b/lib/ffi_yajl/map_library_name.rb
@@ -0,0 +1,37 @@
+
+require 'ffi_yajl/platform'
+
+module FFI_Yajl
+  module MapLibraryName
+    include FFI_Yajl::Platform
+    def map_library_name
+      # this is the right answer for the internally built libyajl on windows
+      return "libyajl.so" if windows?
+
+      # this is largely copied from the FFI.map_library_name algorithm, we most likely need
+      # the windows code eventually to support not using the embedded libyajl2-gem
+      libprefix =
+        case RbConfig::CONFIG['host_os'].downcase
+        when /mingw|mswin/
+          ''
+        when /cygwin/
+          'cyg'
+        else
+          'lib'
+        end
+      libsuffix =
+        case RbConfig::CONFIG['host_os'].downcase
+        when /darwin/
+          'bundle'
+        when /linux|bsd|solaris|sunos/
+          'so'
+        when /mingw|mswin|cygwin/
+          'dll'
+        else
+          # Punt and just assume a sane unix (i.e. anything but AIX)
+          'so'
+        end
+      libprefix + "yajl" + ".#{libsuffix}"
+    end
+  end
+end