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class DeviceDetector
class MemoryCache
DEFAULT_MAX_KEYS = 5000
attr_reader :data, :max_keys, :lock
private :lock
def initialize(config)
@data = {}
@max_keys = config[:max_cache_keys] || DEFAULT_MAX_KEYS
@lock = Mutex.new
end
def set(key, value)
lock.synchronize do
purge_cache
data[String(key)] = value
end
end
def get(key)
data[String(key)]
end
def key?(string_key)
data.key?(string_key)
end
def get_or_set(key, value = nil)
string_key = String(key)
if key?(string_key)
get(string_key)
else
value = yield if block_given?
set(string_key, value)
end
end
private
def purge_cache
key_size = data.size
if key_size >= max_keys
# always remove about 1/3 of keys to reduce garbage collecting
amount_of_keys = key_size / 3
data.keys.first(amount_of_keys).each { |key| data.delete(key) }
end
end
end
end
|
