75 lines
3.0 KiB
Ruby
75 lines
3.0 KiB
Ruby
# 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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class << self
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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 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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# Ensures the questionable path is prefixed with the base directory
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# and prepends the questionable path with the base directory if false.
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#
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# Returns a frozen string.
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def sanitized_path(base_directory, questionable_path)
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@sanitized_path ||= {}
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@sanitized_path[base_directory] ||= {}
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@sanitized_path[base_directory][questionable_path] ||= if questionable_path.nil?
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base_directory.freeze
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else
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sanitize_and_join(
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base_directory, questionable_path
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).freeze
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end
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end
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private
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def sanitize_and_join(base_directory, questionable_path)
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clean_path = if questionable_path.start_with?("~")
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questionable_path.dup.insert(0, "/")
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else
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questionable_path
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end
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clean_path = File.expand_path(clean_path, "/")
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return clean_path if clean_path.eql?(base_directory)
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# remove any remaining extra leading slashes not stripped away by calling
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# `File.expand_path` above.
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clean_path.squeeze!("/")
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return clean_path if clean_path.start_with?(slashed_dir_cache(base_directory))
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clean_path.sub!(%r!\A\w:/!, "/")
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join(base_directory, clean_path)
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end
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def slashed_dir_cache(base_directory)
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@slashed_dir_cache ||= {}
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@slashed_dir_cache[base_directory] ||= base_directory.sub(%r!\z!, "/")
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end
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end
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end
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end
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