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|
module LruRedux
module TTL
class Cache
attr_reader :max_size, :ttl
def initialize(*args)
max_size, ttl = args
ttl ||= :none
raise ArgumentError.new(:max_size) if
max_size < 1
raise ArgumentError.new(:ttl) unless
ttl == :none || ((ttl.is_a? Numeric) && ttl >= 0)
@max_size = max_size
@ttl = ttl
@data_lru = {}
@data_ttl = {}
end
def max_size=(max_size)
max_size ||= @max_size
raise ArgumentError.new(:max_size) if
max_size < 1
@max_size = max_size
resize
end
def ttl=(ttl)
ttl ||= @ttl
raise ArgumentError.new(:ttl) unless
ttl == :none || ((ttl.is_a? Numeric) && ttl >= 0)
@ttl = ttl
ttl_evict
end
def getset(key)
ttl_evict
found = true
value = @data_lru.delete(key){ found = false }
if found
@data_lru[key] = value
else
result = @data_lru[key] = yield
@data_ttl[key] = Time.now.to_f
if @data_lru.size > @max_size
key, _ = @data_lru.first
@data_ttl.delete(key)
@data_lru.delete(key)
end
result
end
end
def fetch(key)
ttl_evict
found = true
value = @data_lru.delete(key){ found = false }
if found
@data_lru[key] = value
else
yield if block_given?
end
end
def [](key)
ttl_evict
found = true
value = @data_lru.delete(key){ found = false }
if found
@data_lru[key] = value
else
nil
end
end
def []=(key, val)
ttl_evict
@data_lru.delete(key)
@data_ttl.delete(key)
@data_lru[key] = val
@data_ttl[key] = Time.now.to_f
if @data_lru.size > @max_size
key, _ = @data_lru.first
@data_ttl.delete(key)
@data_lru.delete(key)
end
val
end
def each
ttl_evict
array = @data_lru.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
ttl_evict
array = @data_lru.to_a
array.reverse!
end
def delete(key)
ttl_evict
@data_lru.delete(key)
@data_ttl.delete(key)
end
alias_method :evict, :delete
def key?(key)
ttl_evict
@data_lru.key?(key)
end
alias_method :has_key?, :key?
def clear
@data_lru.clear
@data_ttl.clear
end
def expire
ttl_evict
end
def count
@data_lru.size
end
protected
# for cache validation only, ensures all is sound
def valid?
@data_lru.size == @data_ttl.size
end
def ttl_evict
return if @ttl == :none
ttl_horizon = Time.now.to_f - @ttl
key, time = @data_ttl.first
until time.nil? || time > ttl_horizon
@data_ttl.delete(key)
@data_lru.delete(key)
key, time = @data_ttl.first
end
end
def resize
ttl_evict
while @data_lru.size > @max_size
key, _ = @data_lru.first
@data_ttl.delete(key)
@data_lru.delete(key)
end
end
end
end
end
|
