Class: CacheXML::Builder

Inherits:
Object
  • Object
show all
Defined in:
lib/thinp_xml/cache/builder.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Builder

Returns a new instance of Builder.



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# File 'lib/thinp_xml/cache/builder.rb', line 10

def initialize
  @uuid = ''
  @block_size = 128
  @nr_cache_blocks = 0
  @policy_name = 'mq'
  @mapping_policy = :random
  @nr_mappings = 0
  @dirty_percentage = 0
  @hint_width = 4
end

Instance Attribute Details

#block_size ⇒ Object

Returns the value of attribute block_size.



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# File 'lib/thinp_xml/cache/builder.rb', line 7

def block_size
  @block_size
end

#dirty_percentage ⇒ Object

Returns the value of attribute dirty_percentage.



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# File 'lib/thinp_xml/cache/builder.rb', line 8

def dirty_percentage
  @dirty_percentage
end

#hint_width ⇒ Object

Returns the value of attribute hint_width.



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# File 'lib/thinp_xml/cache/builder.rb', line 8

def hint_width
  @hint_width
end

#mapping_policy ⇒ Object

Returns the value of attribute mapping_policy.



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# File 'lib/thinp_xml/cache/builder.rb', line 8

def mapping_policy
  @mapping_policy
end

#nr_cache_blocks ⇒ Object

Returns the value of attribute nr_cache_blocks.



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# File 'lib/thinp_xml/cache/builder.rb', line 7

def nr_cache_blocks
  @nr_cache_blocks
end

#nr_mappings ⇒ Object

Returns the value of attribute nr_mappings.



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# File 'lib/thinp_xml/cache/builder.rb', line 8

def nr_mappings
  @nr_mappings
end

#policy_name ⇒ Object

Returns the value of attribute policy_name.



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# File 'lib/thinp_xml/cache/builder.rb', line 7

def policy_name
  @policy_name
end

#uuid ⇒ Object

Returns the value of attribute uuid.



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# File 'lib/thinp_xml/cache/builder.rb', line 7

def uuid
  @uuid
end

Instance Method Details

#generate ⇒ Object 



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# File 'lib/thinp_xml/cache/builder.rb', line 21

def generate
  superblock = Superblock.new(@uuid, @block_size.to_i,
                              @nr_cache_blocks.to_i,
                              @policy_name, @hint_width)
  mappings = []

  case @mapping_policy
  when :linear
    cb = 0
    ob = safe_rand(@nr_cache_blocks - @nr_mappings)

    @nr_mappings.times do
      dirty = safe_rand(100) < @dirty_percentage
      mappings << Mapping.new(cb, ob, dirty)
      cb += 1
      ob += 1
    end

  when :random
    origin_blocks = []

    ob = 0
    @nr_mappings.times do
      origin_blocks << ob
      ob += 1
    end

    0.upto(@nr_mappings - 1) do |n|
      tmp = origin_blocks[n]

      index = n + rand(@nr_mappings - n)
      origin_blocks[n] = origin_blocks[index]
      origin_blocks[index] = tmp

      dirty = safe_rand(100) < @dirty_percentage
      mappings << Mapping.new(n, origin_blocks[n], dirty)
    end

  else
    raise "unknown mapping policy"
  end

  hints = []

  Metadata.new(superblock, mappings, hints)
end