32 lines
1.1 KiB
Ruby
32 lines
1.1 KiB
Ruby
# frozen_string_literal: true
|
|
|
|
module Jekyll
|
|
# A singleton class that caches frozen instances of path strings returned from its methods.
|
|
#
|
|
# NOTE:
|
|
# This class exists because `File.join` allocates an Array and returns a new String on every
|
|
# call using **the same arguments**. Caching the result means reduced memory usage.
|
|
# However, the caches are never flushed so that they can be used even when a site is
|
|
# regenerating. The results are frozen to deter mutation of the cached string.
|
|
#
|
|
# Therefore, employ this class only for situations where caching the result is necessary
|
|
# for performance reasons.
|
|
#
|
|
class PathManager
|
|
# This class cannot be initialized from outside
|
|
private_class_method :new
|
|
|
|
# Wraps `File.join` to cache the frozen result.
|
|
# Reassigns `nil`, empty strings and empty arrays to a frozen empty string beforehand.
|
|
#
|
|
# Returns a frozen string.
|
|
def self.join(base, item)
|
|
base = "" if base.nil? || base.empty?
|
|
item = "" if item.nil? || item.empty?
|
|
@join ||= {}
|
|
@join[base] ||= {}
|
|
@join[base][item] ||= File.join(base, item).freeze
|
|
end
|
|
end
|
|
end
|