Module: NiceFFI::AutoRelease

Included in:
OpaqueStruct, Struct
Defined in:
lib/nice-ffi/autorelease.rb

Overview

A mixin module to provide automatic memory management for C structs.

Class Method Summary collapse

Class Method Details

.included(klass) ⇒ Object

Sets up the class when this module is included. Adds the class

methods and defines class instance variables.



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# File 'lib/nice-ffi/autorelease.rb', line 44

def self.included( klass )
  class << klass

    # Increment the reference count for this address.
    def _incr_refcount( address )
      @ptr_mutex ||= Mutex.new
      @ptr_mutex.synchronize {
        @ptr_refcounts ||= Hash.new(0)
        @ptr_refcounts[address] += 1
      }
      return nil
    end

    # Decrement the counter for this pointer's address, and free
    # the memory if the reference count falls below 1.
    #
    def _release( pointer )
      @ptr_mutex ||= Mutex.new
      @ptr_mutex.synchronize {
        _decr_refcount(pointer.address)
        if( @ptr_refcounts[pointer.address] < 1 )
          release( pointer )
        end
      }
    end

    private

    # Decrement the reference count for this address. If the count falls
    # below 1, the address is removed from Hash altogether.
    #
    # Note: this method does not have a Mutex lock by itself, but you
    # should use a lock in any methods that call it.
    # 
    def _decr_refcount( address )
      @ptr_refcounts ||= Hash.new(0)
      @ptr_refcounts[address] -= 1
      if( @ptr_refcounts[address] < 1 )
        @ptr_refcounts.delete(address)
      end
    end

  end
end