diff options
Diffstat (limited to 'activesupport/lib/active_support/duration')
| -rw-r--r-- | activesupport/lib/active_support/duration/iso8601_parser.rb | 122 | ||||
| -rw-r--r-- | activesupport/lib/active_support/duration/iso8601_serializer.rb | 51 |
2 files changed, 173 insertions, 0 deletions
diff --git a/activesupport/lib/active_support/duration/iso8601_parser.rb b/activesupport/lib/active_support/duration/iso8601_parser.rb new file mode 100644 index 0000000000..07af58ad99 --- /dev/null +++ b/activesupport/lib/active_support/duration/iso8601_parser.rb @@ -0,0 +1,122 @@ +require 'strscan' + +module ActiveSupport + class Duration + # Parses a string formatted according to ISO 8601 Duration into the hash. + # + # See {ISO 8601}[http://en.wikipedia.org/wiki/ISO_8601#Durations] for more information. + # + # This parser allows negative parts to be present in pattern. + class ISO8601Parser # :nodoc: + class ParsingError < ::ArgumentError; end + + PERIOD_OR_COMMA = /\.|,/ + PERIOD = '.'.freeze + COMMA = ','.freeze + + SIGN_MARKER = /\A\-|\+|/ + DATE_MARKER = /P/ + TIME_MARKER = /T/ + DATE_COMPONENT = /(\-?\d+(?:[.,]\d+)?)(Y|M|D|W)/ + TIME_COMPONENT = /(\-?\d+(?:[.,]\d+)?)(H|M|S)/ + + DATE_TO_PART = { 'Y' => :years, 'M' => :months, 'W' => :weeks, 'D' => :days } + TIME_TO_PART = { 'H' => :hours, 'M' => :minutes, 'S' => :seconds } + + DATE_COMPONENTS = [:years, :months, :days] + TIME_COMPONENTS = [:hours, :minutes, :seconds] + + attr_reader :parts, :scanner + attr_accessor :mode, :sign + + def initialize(string) + @scanner = StringScanner.new(string) + @parts = {} + @mode = :start + @sign = 1 + end + + def parse! + while !finished? + case mode + when :start + if scan(SIGN_MARKER) + self.sign = (scanner.matched == '-') ? -1 : 1 + self.mode = :sign + else + raise_parsing_error + end + + when :sign + if scan(DATE_MARKER) + self.mode = :date + else + raise_parsing_error + end + + when :date + if scan(TIME_MARKER) + self.mode = :time + elsif scan(DATE_COMPONENT) + parts[DATE_TO_PART[scanner[2]]] = number * sign + else + raise_parsing_error + end + + when :time + if scan(TIME_COMPONENT) + parts[TIME_TO_PART[scanner[2]]] = number * sign + else + raise_parsing_error + end + + end + end + + validate! + parts + end + + private + + def finished? + scanner.eos? + end + + # Parses number which can be a float with either comma or period. + def number + scanner[1] =~ PERIOD_OR_COMMA ? scanner[1].tr(COMMA, PERIOD).to_f : scanner[1].to_i + end + + def scan(pattern) + scanner.scan(pattern) + end + + def raise_parsing_error(reason = nil) + raise ParsingError, "Invalid ISO 8601 duration: #{scanner.string.inspect} #{reason}".strip + end + + # Checks for various semantic errors as stated in ISO 8601 standard. + def validate! + raise_parsing_error('is empty duration') if parts.empty? + + # Mixing any of Y, M, D with W is invalid. + if parts.key?(:weeks) && (parts.keys & DATE_COMPONENTS).any? + raise_parsing_error('mixing weeks with other date parts not allowed') + end + + # Specifying an empty T part is invalid. + if mode == :time && (parts.keys & TIME_COMPONENTS).empty? + raise_parsing_error('time part marker is present but time part is empty') + end + + fractions = parts.values.reject(&:zero?).select { |a| (a % 1) != 0 } + unless fractions.empty? || (fractions.size == 1 && fractions.last == @parts.values.reject(&:zero?).last) + raise_parsing_error '(only last part can be fractional)' + end + + return true + end + end + end +end diff --git a/activesupport/lib/active_support/duration/iso8601_serializer.rb b/activesupport/lib/active_support/duration/iso8601_serializer.rb new file mode 100644 index 0000000000..05c6a083a9 --- /dev/null +++ b/activesupport/lib/active_support/duration/iso8601_serializer.rb @@ -0,0 +1,51 @@ +require 'active_support/core_ext/object/blank' +require 'active_support/core_ext/hash/transform_values' + +module ActiveSupport + class Duration + # Serializes duration to string according to ISO 8601 Duration format. + class ISO8601Serializer + def initialize(duration, precision: nil) + @duration = duration + @precision = precision + end + + # Builds and returns output string. + def serialize + output = 'P' + parts, sign = normalize + output << "#{parts[:years]}Y" if parts.key?(:years) + output << "#{parts[:months]}M" if parts.key?(:months) + output << "#{parts[:weeks]}W" if parts.key?(:weeks) + output << "#{parts[:days]}D" if parts.key?(:days) + time = '' + time << "#{parts[:hours]}H" if parts.key?(:hours) + time << "#{parts[:minutes]}M" if parts.key?(:minutes) + if parts.key?(:seconds) + time << "#{sprintf(@precision ? "%0.0#{@precision}f" : '%g', parts[:seconds])}S" + end + output << "T#{time}" if time.present? + "#{sign}#{output}" + end + + private + + # Return pair of duration's parts and whole duration sign. + # Parts are summarized (as they can become repetitive due to addition, etc). + # Zero parts are removed as not significant. + # If all parts are negative it will negate all of them and return minus as a sign. + def normalize + parts = @duration.parts.each_with_object(Hash.new(0)) do |(k,v),p| + p[k] += v unless v.zero? + end + # If all parts are negative - let's make a negative duration + sign = '' + if parts.values.all? { |v| v < 0 } + sign = '-' + parts.transform_values!(&:-@) + end + [parts, sign] + end + end + end +end |