Class: IdentityCache::MemoizedCacheProxy

Inherits:
Object
  • Object
show all
Defined in:
lib/identity_cache/memoized_cache_proxy.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(cache_adaptor = nil) ⇒ MemoizedCacheProxy

Returns a new instance of MemoizedCacheProxy.



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# File 'lib/identity_cache/memoized_cache_proxy.rb', line 7

def initialize(cache_adaptor = nil)
  self.cache_backend = cache_adaptor || Rails.cache
  @key_value_maps = Hash.new {|h, k| h[k] = {} }
end

Instance Attribute Details

#cache_fetcher ⇒ Object (readonly)

Returns the value of attribute cache_fetcher.



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# File 'lib/identity_cache/memoized_cache_proxy.rb', line 5

def cache_fetcher
  @cache_fetcher
end

Instance Method Details

#cache_backend=(cache_adaptor) ⇒ Object 



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# File 'lib/identity_cache/memoized_cache_proxy.rb', line 12

def cache_backend=(cache_adaptor)
  if cache_adaptor.respond_to?(:cas) && cache_adaptor.respond_to?(:cas_multi)
    @cache_fetcher = CacheFetcher.new(cache_adaptor)
  else
    @cache_fetcher = FallbackFetcher.new(cache_adaptor)
  end
end

#clear ⇒ Object 



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# File 'lib/identity_cache/memoized_cache_proxy.rb', line 109

def clear
  clear_memoization
  @cache_fetcher.clear
end

#delete(key) ⇒ Object 



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# File 'lib/identity_cache/memoized_cache_proxy.rb', line 37

def delete(key)
  memoized_key_values.delete(key) if memoizing?
  result = @cache_fetcher.delete(key)
  IdentityCache.logger.debug { "[IdentityCache] delete #{ result ? 'recorded'  : 'failed'  } for #{key}" }
  result
end

#fetch(key) ⇒ Object 



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# File 'lib/identity_cache/memoized_cache_proxy.rb', line 44

def fetch(key)
  used_cache_backend = true
  missed = false
  value = if memoizing?
    used_cache_backend = false
    memoized_key_values.fetch(key) do
      used_cache_backend = true
      memoized_key_values[key] = @cache_fetcher.fetch(key) do
        missed = true
        yield
      end
    end
  else
    @cache_fetcher.fetch(key) do
      missed = true
      yield
    end
  end

  if missed
    IdentityCache.logger.debug { "[IdentityCache] cache miss for #{key}" }
  else
    IdentityCache.logger.debug { "[IdentityCache] #{ used_cache_backend ? '(cache_backend)' : '(memoized)' } cache hit for #{key}" }
  end

  value
end

#fetch_multi(*keys) ⇒ Object 



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# File 'lib/identity_cache/memoized_cache_proxy.rb', line 72

def fetch_multi(*keys)
  memoized_keys, missed_keys = [], [] if IdentityCache.logger.debug?

  result = if memoizing?
    hash = {}
    mkv = memoized_key_values

    non_memoized_keys = keys.reject do |key|
      if mkv.has_key?(key)
        memoized_keys << key if IdentityCache.logger.debug?
        hit = mkv[key]
        hash[key] = hit unless hit.nil?
        true
      end
    end

    unless non_memoized_keys.empty?
      results = @cache_fetcher.fetch_multi(non_memoized_keys) do |missing_keys|
        missed_keys.concat(missing_keys) if IdentityCache.logger.debug?
        yield missing_keys
      end
      mkv.merge! results
      hash.merge! results
    end
    hash
  else
    @cache_fetcher.fetch_multi(keys) do |missing_keys|
      missed_keys.concat(missing_keys) if IdentityCache.logger.debug?
      yield missing_keys
    end
  end

  log_multi_result(memoized_keys, keys - missed_keys - memoized_keys, missed_keys) if IdentityCache.logger.debug?

  result
end

#memoized_key_values ⇒ Object 



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# File 'lib/identity_cache/memoized_cache_proxy.rb', line 20

def memoized_key_values
  @key_value_maps[Thread.current]
end

#with_memoization(&block) ⇒ Object 



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# File 'lib/identity_cache/memoized_cache_proxy.rb', line 24

def with_memoization(&block)
  Thread.current[:memoizing_idc] = true
  yield
ensure
  clear_memoization
  Thread.current[:memoizing_idc] = false
end

#write(key, value) ⇒ Object 



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# File 'lib/identity_cache/memoized_cache_proxy.rb', line 32

def write(key, value)
  memoized_key_values[key] = value if memoizing?
  @cache_fetcher.write(key, value)
end