Move with_self open-with-block helper to common module from posix semaphore implementation.

lib/process_shared/posix/semaphore.rb

@@ -1,8 +1,9 @@
+require 'process_shared/semaphore'
+
 require 'process_shared/posix/errno'
 require 'process_shared/posix/libc'
 require 'process_shared/posix/time_val'
 require 'process_shared/posix/time_spec'
-require 'process_shared/with_self'
 
 module ProcessShared
   module Posix
@@ -34,7 +35,7 @@ module ProcessShared
       end
 
       include Foreign
-      include ProcessShared::WithSelf
+      include ProcessShared::Semaphore
 
       # Make a Proc suitable for use as a finalizer that will call
       # +shm_unlink+ on +sem+.
@@ -44,17 +45,6 @@ module ProcessShared
         proc { LibC.shm_unlink(sem) }
       end
 
-      # With no associated block, open is a synonym for
-      # Semaphore.new. If the optional code block is given, it will be
-      # passed +sem+ as an argument, and the Semaphore object will
-      # automatically be closed when the block terminates. In this
-      # instance, Semaphore.open returns the value of the block.
-      #
-      # @param [Integer] value the initial semaphore value
-      def self.open(value = 1, &block)
-        new(value).with_self(&block)
-      end
-
       # Create a new semaphore with initial value +value+.  After
       # Kernel#fork, the semaphore will be shared across two (or more)
       # processes. The semaphore must be closed with #close in each

lib/process_shared/semaphore.rb

@@ -1,84 +1,37 @@
-require 'process_shared/psem'
-require 'process_shared/abstract_semaphore'
+require 'process_shared/with_self'
 
 module ProcessShared
-  class Semaphore < AbstractSemaphore
-    # With no associated block, open is a synonym for
-    # Semaphore.new. If the optional code block is given, it will be
-    # passed +sem+ as an argument, and the Semaphore object will
-    # automatically be closed when the block terminates. In this
-    # instance, Semaphore.open returns the value of the block.
-    #
-    # @param [Integer] value the initial semaphore value
-    # @param [String] name not currently supported
-    def self.open(value = 1, name = nil, &block)
-      new(value, name).with_self(&block)
-    end
+  module Semaphore
+    include ProcessShared::WithSelf
 
-    # Create a new semaphore with initial value +value+.  After
-    # Kernel#fork, the semaphore will be shared across two (or more)
-    # processes. The semaphore must be closed with #close in each
-    # process that no longer needs the semaphore.
-    #
-    # (An object finalizer is registered that will close the semaphore
-    # to avoid memory leaks, but this should be considered a last
-    # resort).
-    #
-    # @param [Integer] value the initial semaphore value
-    # @param [String] name not currently supported
-    def initialize(value = 1, name = nil)
-      init(PSem.sizeof_psem_t, 'psem', name) do |sem_name|
-        psem_open(sem, sem_name, value, err)
+    class << self
+      # the implementation to use to create semaphores.  impl is set
+      # based on the platform in 'process_shared'
+      attr_accessor :impl
+      
+      def new(*args)
+        impl.new(*args)
+      end
+
+      # With no associated block, open is a synonym for
+      # Semaphore.new. If the optional code block is given, it will be
+      # passed +sem+ as an argument, and the Semaphore object will
+      # automatically be closed when the block terminates. In this
+      # instance, Semaphore.open returns the value of the block.
+      #
+      # @param [Integer] value the initial semaphore value
+      def open(value = 1, &block)
+        new(value).with_self(&block)
       end
     end
 
-    # Decrement the value of the semaphore.  If the value is zero,
-    # wait until another process increments via {#post}.
-    def wait
-      psem_wait(sem, err)
-    end
-
-    # Decrement the value of the semaphore if it can be done
-    # immediately (i.e. if it was non-zero).  Otherwise, wait up to
-    # +timeout+ seconds until another process increments via {#post}.
-    #
-    # @param timeout [Numeric] the maximum seconds to wait, or nil to not wait
-    #
-    # @return If +timeout+ is nil and the semaphore cannot be
-    # decremented immediately, raise Errno::EAGAIN.  If +timeout+
-    # passed before the semaphore could be decremented, raise
-    # Errno::ETIMEDOUT.
-    def try_wait(timeout = nil)
-      if timeout
-        psem_timedwait(sem, timeout, err)
-      else
-        psem_trywait(sem, err)
+    def synchronize
+      wait
+      begin
+        yield
+      ensure
+        post
       end
     end
-
-    # Increment the value of the semaphore.  If other processes are
-    # waiting on this semaphore, one will be woken.
-    def post
-      psem_post(sem, err)
-    end
-
-    # Get the current value of the semaphore. Raises {Errno::NOTSUP} on
-    # platforms that don't support this (e.g. Mac OS X).
-    #
-    # @return [Integer] the current value of the semaphore.
-    def value
-      int = FFI::MemoryPointer.new(:int)
-      psem_getvalue(sem, int, err)
-      int.get_int(0)
-    end
-
-    # Release the resources associated with this semaphore.  Calls to
-    # other methods are undefined after {#close} has been called.
-    #
-    # Close must be called when the semaphore is no longer needed.  An
-    # object finalizer will close the semaphore as a last resort.
-    def close
-      psem_close(sem, err)
-    end
   end
 end