JezK
Edit File: non_concurrent_cache_backend.rb
module ThreadSafe class NonConcurrentCacheBackend # WARNING: all public methods of the class must operate on the @backend # directly without calling each other. This is important because of the # SynchronizedCacheBackend which uses a non-reentrant mutex for perfomance # reasons. def initialize(options = nil) @backend = {} end def [](key) @backend[key] end def []=(key, value) @backend[key] = value end def compute_if_absent(key) if NULL != (stored_value = @backend.fetch(key, NULL)) stored_value else @backend[key] = yield end end def replace_pair(key, old_value, new_value) if pair?(key, old_value) @backend[key] = new_value true else false end end def replace_if_exists(key, new_value) if NULL != (stored_value = @backend.fetch(key, NULL)) @backend[key] = new_value stored_value end end def compute_if_present(key) if NULL != (stored_value = @backend.fetch(key, NULL)) store_computed_value(key, yield(stored_value)) end end def compute(key) store_computed_value(key, yield(@backend[key])) end def merge_pair(key, value) if NULL == (stored_value = @backend.fetch(key, NULL)) @backend[key] = value else store_computed_value(key, yield(stored_value)) end end def get_and_set(key, value) stored_value = @backend[key] @backend[key] = value stored_value end def key?(key) @backend.key?(key) end def value?(value) @backend.value?(value) end def delete(key) @backend.delete(key) end def delete_pair(key, value) if pair?(key, value) @backend.delete(key) true else false end end def clear @backend.clear self end def each_pair dupped_backend.each_pair do |k, v| yield k, v end self end def size @backend.size end def get_or_default(key, default_value) @backend.fetch(key, default_value) end alias_method :_get, :[] alias_method :_set, :[]= private :_get, :_set private def initialize_copy(other) super @backend = {} self end def dupped_backend @backend.dup end def pair?(key, expected_value) NULL != (stored_value = @backend.fetch(key, NULL)) && expected_value.equal?(stored_value) end def store_computed_value(key, new_value) if new_value.nil? @backend.delete(key) nil else @backend[key] = new_value end end end end