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