Split SharedMemory into module and platform dependent bits. Make SharedArray extend platform dependent class.

lib/process_shared.rb

@@ -19,7 +19,23 @@ if RUBY_VERSION =~ /^1.8/
 end
 
 require 'process_shared/semaphore'
-require 'process_shared/bounded_semaphore'
+require 'process_shared/binary_semaphore'
 require 'process_shared/mutex'
 require 'process_shared/shared_memory'
 
+module ProcessShared
+  case FFI::Platform::OS
+  when 'linux'
+    require 'process_shared/posix/shared_memory'
+    require 'process_shared/posix/semaphore'
+
+    SharedMemory.impl = Posix::SharedMemory
+    Semaphore.impl = Posix::Semaphore
+  when 'darwin'
+    require 'process_shared/posix/shared_memory'
+    require 'process_shared/mach/semaphore'
+
+    SharedMemory.impl = Posix::SharedMemory
+    Semaphore.impl = Mach::Semaphore
+  end
+end

lib/process_shared/posix/shared_memory.rb

@@ -2,8 +2,7 @@ require 'ffi'
 
 require 'process_shared/posix/errno'
 require 'process_shared/posix/libc'
-require 'process_shared/shared_memory_io'
-require 'process_shared/with_self'
+require 'process_shared/shared_memory'
 
 module ProcessShared
   module Posix
@@ -29,14 +28,10 @@ module ProcessShared
       include SharedMemory::Foreign
       include LibC
       
-      include ProcessShared::WithSelf
+      include ProcessShared::SharedMemory
 
       attr_reader :size, :type, :type_size, :count, :fd
 
-      def self.open(size, &block)
-        new(size).with_self(&block)
-      end
-
       def self.make_finalizer(addr, size, fd)
         proc do
           pointer = FFI::Pointer.new(addr)
@@ -78,60 +73,10 @@ module ProcessShared
         super(@pointer)
       end
 
-      # Write the serialization of +obj+ (using Marshal.dump) to this
-      # shared memory object at +offset+ (in bytes).
-      #
-      # Raises IndexError if there is insufficient space.
-      def put_object(offset, obj)
-        # FIXME: This is a workaround to an issue I'm seeing in
-        # 1.8.7-p352 (not tested in other 1.8's).  If I used the code
-        # below that works in 1.9, then inside SharedMemoryIO#write, the
-        # passed string object is 'terminated' (garbage collected?) and
-        # won't respond to any methods...  This less efficient since it
-        # involves the creation of an intermediate string, but it works
-        # in 1.8.7-p352.
-        if RUBY_VERSION =~ /^1.8/
-          str = Marshal.dump(obj)
-          return put_bytes(offset, str, 0, str.size)
-        end
-
-        io = to_shm_io
-        io.seek(offset)
-        Marshal.dump(obj, io)
-      end
-
-      # Read the serialized object at +offset+ (in bytes) using
-      # Marshal.load.
-      #
-      # @return [Object]
-      def get_object(offset)
-        io = to_shm_io
-        io.seek(offset)
-        Marshal.load(io)
-      end
-
-      # Equivalent to {#put_object(0, obj)}
-      def write_object(obj)
-        put_object(0, obj)
-      end
-
-      # Equivalent to {#read_object(0, obj)}
-      #
-      # @return [Object]
-      def read_object
-        Marshal.load(to_shm_io)
-      end
-
       def close
         ObjectSpace.undefine_finalizer(self)
         @finalize.call
       end
-
-      private
-
-      def to_shm_io
-        ProcessShared::SharedMemoryIO.new(self)
-      end
     end
   end
 end

lib/process_shared/shared_array.rb

@@ -1,5 +1,7 @@
+require 'process_shared'
+
 module ProcessShared
-  class SharedArray < SharedMemory
+  class SharedArray < SharedMemory.impl
     include Enumerable
 
     # A fixed-size array in shared memory.  Processes forked from this

lib/process_shared/shared_memory.rb

@@ -5,54 +5,19 @@ require 'process_shared/shared_memory_io'
 
 module ProcessShared
   # Memory block shared across processes.
-  class SharedMemory < FFI::Pointer
-    include WithSelf
+  module SharedMemory
+    include ProcessShared::WithSelf
 
-    attr_reader :size, :type, :type_size, :count, :fd
+    class << self
+      attr_accessor :impl
 
-    def self.open(size, &block)
-      new(size).with_self(&block)
-    end
-
-    def self.make_finalizer(addr, size, fd)
-      proc do
-        pointer = FFI::Pointer.new(addr)
-        LibC.munmap(pointer, size)
-        LibC.close(fd)
+      def new(*args)
+        impl.new(*args)
       end
-    end
 
-    def initialize(type_or_count = 1, count = 1)
-      @type, @count = case type_or_count
-                      when Symbol
-                        [type_or_count, count]
-                      else
-                        [:uchar, type_or_count]
-                      end
-
-      @type_size = FFI.type_size(@type)
-      @size = @type_size * @count
-
-      name = "/ps-shm#{rand(10000)}"
-      @fd = RT.shm_open(name,
-                        LibC::O_CREAT | LibC::O_RDWR | LibC::O_EXCL,
-                        0777)
-      RT.shm_unlink(name)
-      
-      LibC.ftruncate(@fd, @size)
-      @pointer = LibC.mmap(nil,
-                           @size,
-                           LibC::PROT_READ | LibC::PROT_WRITE,
-                           LibC::MAP_SHARED,
-                           @fd,
-                           0).
-        slice(0, size) # slice to get FFI::Pointer that knows its size
-                       # (and thus does bounds checking)
-
-      @finalize = self.class.make_finalizer(@pointer.address, @size, @fd)
-      ObjectSpace.define_finalizer(self, @finalize)
-
-      super(@pointer)
+      def open(size, &block)
+        new(size).with_self(&block)
+      end
     end
 
     # Write the serialization of +obj+ (using Marshal.dump) to this
@@ -99,12 +64,7 @@ module ProcessShared
       Marshal.load(to_shm_io)
     end
 
-    def close
-      ObjectSpace.undefine_finalizer(self)
-      @finalize.call
-    end
-
-    private
+    protected
 
     def to_shm_io
       SharedMemoryIO.new(self)

spec/process_shared/shared_memory_spec.rb

@@ -1,5 +1,5 @@
 require 'spec_helper'
-require 'process_shared/shared_memory'
+require 'process_shared'
 
 module ProcessShared
   describe SharedMemory do