109 lines
2.9 KiB
Ruby
109 lines
2.9 KiB
Ruby
# frozen_string_literal: true
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# A serializer for boolean values being stored in Redis.
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#
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# This is to ensure that booleans are stored in a consistent and
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# testable way when being stored as strings in Redis.
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#
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# Examples:
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#
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# bool = Gitlab::Redis::Boolean.new(true)
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# bool.to_s == "_b:1"
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#
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# Gitlab::Redis::Boolean.encode(true)
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# => "_b:1"
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#
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# Gitlab::Redis::Boolean.decode("_b:1")
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# => true
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#
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# Gitlab::Redis::Boolean.true?("_b:1")
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# => true
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#
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# Gitlab::Redis::Boolean.true?("_b:0")
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# => false
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module Gitlab
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module Redis
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class Boolean
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LABEL = "_b"
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DELIMITER = ":"
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TRUE_STR = "1"
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FALSE_STR = "0"
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BooleanError = Class.new(StandardError)
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NotABooleanError = Class.new(BooleanError)
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NotAnEncodedBooleanStringError = Class.new(BooleanError)
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def initialize(value)
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@value = value
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end
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# @return [String] the encoded boolean
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def to_s
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self.class.encode(@value)
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end
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class << self
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# Turn a boolean into a string for storage in Redis
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#
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# @param value [Boolean] true or false
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# @return [String] the encoded boolean
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# @raise [NotABooleanError] if the value isn't true or false
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def encode(value)
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raise NotABooleanError, value unless bool?(value)
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[LABEL, to_string(value)].join(DELIMITER)
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end
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# Decode a boolean string
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#
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# @param value [String] the stored boolean string
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# @return [Boolean] true or false
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# @raise [NotAnEncodedBooleanStringError] if the provided value isn't an encoded boolean
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def decode(value)
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raise NotAnEncodedBooleanStringError, value.class unless value.is_a?(String)
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label, bool_str = *value.split(DELIMITER, 2)
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raise NotAnEncodedBooleanStringError, label unless label == LABEL
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from_string(bool_str)
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end
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# Decode a boolean string, then test if it's true
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#
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# @param value [String] the stored boolean string
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# @return [Boolean] is the value true?
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# @raise [NotAnEncodedBooleanStringError] if the provided value isn't an encoded boolean
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def true?(encoded_value)
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decode(encoded_value)
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end
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# Decode a boolean string, then test if it's false
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#
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# @param value [String] the stored boolean string
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# @return [Boolean] is the value false?
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# @raise [NotAnEncodedBooleanStringError] if the provided value isn't an encoded boolean
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def false?(encoded_value)
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!true?(encoded_value)
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end
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private
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def bool?(value)
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[true, false].include?(value)
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end
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def to_string(bool)
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bool ? TRUE_STR : FALSE_STR
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end
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def from_string(str)
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raise NotAnEncodedBooleanStringError, str unless [TRUE_STR, FALSE_STR].include?(str)
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str == TRUE_STR
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end
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end
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end
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end
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end
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