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# Ruby 1.9 makes our life easier, Hash is already ordered
#
# This is an ultra efficient 1.9 freindly implementation
class LruRedux::Cache
def initialize(*args)
max_size, _ = args
raise ArgumentError.new(:max_size) if max_size < 1
@max_size = max_size
@data = {}
end
def max_size=(max_size)
max_size ||= @max_size
raise ArgumentError.new(:max_size) if max_size < 1
@max_size = max_size
@data.shift while @data.size > @max_size
end
def ttl=(_)
nil
end
def getset(key)
found = true
value = @data.delete(key){ found = false }
if found
@data[key] = value
else
result = @data[key] = yield
@data.shift if @data.length > @max_size
result
end
end
def fetch(key)
found = true
value = @data.delete(key){ found = false }
if found
@data[key] = value
else
yield if block_given?
end
end
def [](key)
found = true
value = @data.delete(key){ found = false }
if found
@data[key] = value
else
nil
end
end
def []=(key,val)
@data.delete(key)
@data[key] = val
@data.shift if @data.length > @max_size
val
end
def each
array = @data.to_a
array.reverse!.each do |pair|
yield pair
end
end
# used further up the chain, non thread safe each
alias_method :each_unsafe, :each
def to_a
array = @data.to_a
array.reverse!
end
def delete(key)
@data.delete(key)
end
alias_method :evict, :delete
def key?(key)
@data.key?(key)
end
alias_method :has_key?, :key?
def clear
@data.clear
end
def count
@data.size
end
protected
# for cache validation only, ensures all is sound
def valid?
true
end
end
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