Class: ActiveSupport::Cache::Entry

Inherits:
Object
  • Object
show all
Defined in:
activesupport/lib/active_support/cache.rb

Overview

This class is used to represent cache entries. Cache entries have a value, an optional expiration time, and an optional version. The expiration time is used to support the :race_condition_ttl option on the cache. The version is used to support the :version option on the cache for rejecting mismatches.

Since cache entries in most instances will be serialized, the internals of this class are highly optimized using short instance variable names that are lazily defined.

Constant Summary collapse

DEFAULT_COMPRESS_LIMIT = 
16.kilobytes

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(value, options = {}) ⇒ Entry

Creates a new cache entry for the specified value. Options supported are :compress, :compress_threshold, and :expires_in.



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# File 'activesupport/lib/active_support/cache.rb', line 665

def initialize(value, options = {})
  if should_compress?(value, options)
    @value = compress(value)
    @compressed = true
  else
    @value = value
  end

  @version    = options[:version]
  @created_at = Time.now.to_f
  @expires_in = options[:expires_in]
  @expires_in = @expires_in.to_f if @expires_in
end

Instance Attribute Details

#version ⇒ Object (readonly)

:nodoc:



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# File 'activesupport/lib/active_support/cache.rb', line 659

def version
  @version
end

Instance Method Details

#dup_value! ⇒ Object

Duplicates the value in a class. This is used by cache implementations that don’t natively serialize entries to protect against accidental cache modifications.



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# File 'activesupport/lib/active_support/cache.rb', line 724

def dup_value!
  if @value && !compressed? && !(@value.is_a?(Numeric) || @value == true || @value == false)
    if @value.is_a?(String)
      @value = @value.dup
    else
      @value = Marshal.load(Marshal.dump(@value))
    end
  end
end

#expired? ⇒ Boolean

Checks if the entry is expired. The expires_in parameter can override the value set when the entry was created.



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# File 'activesupport/lib/active_support/cache.rb', line 689

def expired?
  @expires_in && @created_at + @expires_in <= Time.now.to_f
end

#expires_at ⇒ Object 



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# File 'activesupport/lib/active_support/cache.rb', line 693

def expires_at
  @expires_in ? @created_at + @expires_in : nil
end

#expires_at=(value) ⇒ Object 



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# File 'activesupport/lib/active_support/cache.rb', line 697

def expires_at=(value)
  if value
    @expires_in = value.to_f - @created_at
  else
    @expires_in = nil
  end
end

#mismatched?(version) ⇒ Boolean 



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# File 'activesupport/lib/active_support/cache.rb', line 683

def mismatched?(version)
  @version && version && @version != version
end

#size ⇒ Object

Returns the size of the cached value. This could be less than value.size if the data is compressed.



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# File 'activesupport/lib/active_support/cache.rb', line 707

def size
  if defined?(@s)
    @s
  else
    case value
    when NilClass
      0
    when String
      @value.bytesize
    else
      @s = Marshal.dump(@value).bytesize
    end
  end
end

#value ⇒ Object 



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# File 'activesupport/lib/active_support/cache.rb', line 679

def value
  compressed? ? uncompress(@value) : @value
end