Module: When::Parts::MethodCash

Included in:
Coordinates::Temporal, Ephemeris::Formula
Defined in:
lib/when_exe/parts/method_cash.rb

Overview

メソッドの実行結果をキャッシュし処理の高速化を行う

fn というメソッドをキャッシュ化

* fn

a_to_b と b_to_a という互いに逆関数のメソッドをキャッシュ化

* a_to_b

特記事項

Argument identification

The eql? method of When::TM::(Temporal)Position is not overridden.
It seems that the cost of identification of the argument exceeds the merit of the method cash.
I do not recommend applying the methodcash to the method which takes
When::TM::(Temporal)Position as an argument.

Multi-thread critical situation

There is a problem in consistency of hash when this function is used in multi-thread environment.
If the initialize method sets Mutex in instance variable @_m_cash_lock_,
this function gives up use of hash in the critical situation.

class Foo
  include MethodCash

  def initialize
    ...
    @_m_cash_lock_ = Mutex.new
    ...
   end
end

Constant Summary collapse

Escape = 
{:to_str  => true,
:to_ary  => true,
:to_hash => true}

Class Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(name, *args, &block) ⇒ void

This method returns an undefined value.

最初に発生する method_missing で、キャッシュ機能を登録する



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# File 'lib/when_exe/parts/method_cash.rb', line 136

def method_missing(name, *args, &block)

  return method_missing_(name, *args, &block) unless respond_to?("#{name}_", true)
  return send("#{name}_",  *args, &block) if MethodCash.direct

  if ((name.to_s =~ /\A(_*)(.+?)_to_(.+)\z/) && respond_to?("#{$1}#{$3}_to_#{$2}_", true))
    prefix, from, to = $~[1..3]
    begin
      if (@_m_cash_lock_)
        return send("#{prefix}#{from}_to_#{to}_", *args, &block) unless @_m_cash_lock_.try_lock
        unlock = "ensure ; @_m_cash_lock_.locked? && @_m_cash_lock_.unlock"
      end
      [[from, to],[to, from]].each do |pair|
        a, b = pair
        lock = @_m_cash_lock_ ? "  return #{prefix}#{a}_to_#{b}_(*args) unless @_m_cash_lock_.try_lock" : ''
        instance_eval %Q{
          def #{prefix}#{a}_to_#{b}(*args)
            key = _key_simplefy(args)
            inv = @_m_cash_["#{prefix}#{a}_to_#{b}"][key]
            return inv if inv
            begin
            #{lock}
              inv = #{prefix}#{a}_to_#{b}_(*args)
              @_m_cash_["#{prefix}#{b}_to_#{a}"][_key_simplefy(inv)] = args
              @_m_cash_["#{prefix}#{a}_to_#{b}"][key] = inv
              return inv
            #{unlock}
            end
          end
        }
      end
      key = _key_simplefy(args)
      inv = send("#{prefix}#{from}_to_#{to}_", *args)
      @_m_cash_ ||= {}
      @_m_cash_["#{prefix}#{to}_to_#{from}"]    ||= {}
      @_m_cash_["#{prefix}#{from}_to_#{to}"]    ||= {}
      @_m_cash_["#{prefix}#{to}_to_#{from}"][_key_simplefy(inv)] = args
      @_m_cash_["#{prefix}#{from}_to_#{to}"][key] = inv
      return inv
    ensure
      @_m_cash_lock_ && @_m_cash_lock_.locked? && @_m_cash_lock_.unlock
    end

  else
    begin
      respond = respond_to?("#{name}_setup", true)
      setup   = respond ? "#{name}_setup(key, *args)" :
                          "(@_m_cash_[\"#{name}\"][key] = #{name}_(*args))"
      if (@_m_cash_lock_)
        return send("#{name}_", *args, &block) unless @_m_cash_lock_.try_lock
        lock   = "  return #{name}_(*args) unless @_m_cash_lock_.try_lock"
        unlock = "ensure ; @_m_cash_lock_.locked? && @_m_cash_lock_.unlock"
      end
      instance_eval %Q{
        def #{name}(*args)
          key = _key_simplefy(args)
          ret = @_m_cash_["#{name}"][key]
          return ret if ret
          begin
          #{lock}
            return #{setup}
          #{unlock}
          end
        end
      }
      key = _key_simplefy(args)
      @_m_cash_ ||= {}
      @_m_cash_["#{name}"] ||= {}
      if (respond)
        return send("#{name}_setup", key, *args)
      else
        return(@_m_cash_["#{name}"][key] ||= send("#{name}_", *args))
      end
    ensure
      @_m_cash_lock_ && @_m_cash_lock_.locked? && @_m_cash_lock_.unlock
    end
  end
end

Class Attribute Details

.direct ⇒ Boolean

‘_’ で終わるメソッドをキャッシュせずに毎回計算するか否か



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# File 'lib/when_exe/parts/method_cash.rb', line 66

def direct
  @direct
end

Class Method Details

._setup_(options = {}) ⇒ void

Note:

When::TM::Calendar クラスの一部はキャッシュ使用を前提としているため :direct=>true では動作しません

This method returns an undefined value.

When::Parts::MethodCash のグローバルな設定を行う

Options Hash (options):

  • :direct (Boolean) —

    ‘_’ で終わるメソッドをキャッシュせずに毎回計算するか否か

  • :escape (Hash{Symbol=>boolean}) —

    毎回 method_missing を発生させるメソッドを true にする

  • :escape (false, nil) —

    to_str, to_ary, to_hash のみ毎回 method_missing を発生させる

  • :escape (true) —

    すべて毎回 method_missing を発生させる



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# File 'lib/when_exe/parts/method_cash.rb', line 80

def _setup_(options={})
  @_setup_info = options
  @direct      = options[:direct]
  case options[:escape]
  when true
    instance_eval %Q{
      def escape(method)
        true
      end
    }
  when Hash
    @escape = Escape.merge(options[:escape])
    instance_eval %Q{
      def escape(method)
        @escape[method]
      end
    }
  else
    instance_eval %Q{
      def escape(method)
        Escape.key?(method)
      end
    }
  end
end

._setup_info ⇒ Hash

設定情報を取得する



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# File 'lib/when_exe/parts/method_cash.rb', line 110

def _setup_info
  @_setup_info ||= {}
end

.escape(method) ⇒ boolean

method_missing メソッドを forward するか否か



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# File 'lib/when_exe/parts/method_cash.rb', line 120

def escape(method)
  Escape.key?(method)
end

Instance Method Details

#method_missing_ ⇒ Object 



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# File 'lib/when_exe/parts/method_cash.rb', line 125

alias :method_missing_ :method_missing