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Diffstat (limited to 'ruby/lib/google/protobuf/repeated_field.rb')
-rw-r--r-- | ruby/lib/google/protobuf/repeated_field.rb | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/ruby/lib/google/protobuf/repeated_field.rb b/ruby/lib/google/protobuf/repeated_field.rb new file mode 100644 index 00000000..831e0320 --- /dev/null +++ b/ruby/lib/google/protobuf/repeated_field.rb @@ -0,0 +1,188 @@ +# Protocol Buffers - Google's data interchange format +# Copyright 2008 Google Inc. All rights reserved. +# https://developers.google.com/protocol-buffers/ +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions are +# met: +# +# * Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# * Redistributions in binary form must reproduce the above +# copyright notice, this list of conditions and the following disclaimer +# in the documentation and/or other materials provided with the +# distribution. +# * Neither the name of Google Inc. nor the names of its +# contributors may be used to endorse or promote products derived from +# this software without specific prior written permission. +# +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +require 'forwardable' + +# +# This class makes RepeatedField act (almost-) like a Ruby Array. +# It has convenience methods that extend the core C or Java based +# methods. +# +# This is a best-effort to mirror Array behavior. Two comments: +# 1) patches always welcome :) +# 2) if performance is an issue, feel free to rewrite the method +# in jruby and C. The source code has plenty of examples +# +# KNOWN ISSUES +# - #[]= doesn't allow less used approaches such as `arr[1, 2] = 'fizz'` +# - #concat should return the orig array +# - #push should accept multiple arguments and push them all at the same time +# +module Google + module Protobuf + class RepeatedField + extend Forwardable + + # methods defined in C or Java: + # + + # [], at + # []= + # concat + # clear + # dup, clone + # each + # push, << + # replace + # length, size + # == + # to_ary, to_a + # also all enumerable + # + # NOTE: using delegators rather than method_missing to make the + # relationship explicit instead of implicit + def_delegators :to_ary, + :&, :*, :-, :'<=>', + :assoc, :bsearch, :bsearch_index, :combination, :compact, :count, + :cycle, :dig, :drop, :drop_while, :eql?, :fetch, :find_index, :flatten, + :include?, :index, :inspect, :join, + :pack, :permutation, :product, :pretty_print, :pretty_print_cycle, + :rassoc, :repeated_combination, :repeated_permutation, :reverse, + :rindex, :rotate, :sample, :shuffle, :shelljoin, :slice, + :to_s, :transpose, :uniq, :| + + + def first(n=nil) + n ? self[0..n] : self[0] + end + + + def last(n=nil) + n ? self[(self.size-n-1)..-1] : self[-1] + end + + + def pop(n=nil) + if n + results = [] + n.times{ results << pop_one } + return results + else + return pop_one + end + end + + + def empty? + self.size == 0 + end + + # array aliases into enumerable + alias_method :each_index, :each_with_index + alias_method :slice, :[] + alias_method :values_at, :select + alias_method :map, :collect + + + class << self + def define_array_wrapper_method(method_name) + define_method(method_name) do |*args, &block| + arr = self.to_a + result = arr.send(method_name, *args) + self.replace(arr) + return result if result + return block ? block.call : result + end + end + private :define_array_wrapper_method + + + def define_array_wrapper_with_result_method(method_name) + define_method(method_name) do |*args, &block| + # result can be an Enumerator, Array, or nil + # Enumerator can sometimes be returned if a block is an optional argument and it is not passed in + # nil usually specifies that no change was made + result = self.to_a.send(method_name, *args, &block) + if result + new_arr = result.to_a + self.replace(new_arr) + if result.is_a?(Enumerator) + # generate a fresh enum; rewinding the exiting one, in Ruby 2.2, will + # reset the enum with the same length, but all the #next calls will + # return nil + result = new_arr.to_enum + # generate a wrapper enum so any changes which occur by a chained + # enum can be captured + ie = ProxyingEnumerator.new(self, result) + result = ie.to_enum + end + end + result + end + end + private :define_array_wrapper_with_result_method + end + + + %w(delete delete_at delete_if shift slice! unshift).each do |method_name| + define_array_wrapper_method(method_name) + end + + + %w(collect! compact! fill flatten! insert reverse! + rotate! select! shuffle! sort! sort_by! uniq!).each do |method_name| + define_array_wrapper_with_result_method(method_name) + end + alias_method :keep_if, :select! + alias_method :map!, :collect! + alias_method :reject!, :delete_if + + + # propagates changes made by user of enumerator back to the original repeated field. + # This only applies in cases where the calling function which created the enumerator, + # such as #sort!, modifies itself rather than a new array, such as #sort + class ProxyingEnumerator < Struct.new(:repeated_field, :external_enumerator) + def each(*args, &block) + results = [] + external_enumerator.each_with_index do |val, i| + result = yield(val) + results << result + #nil means no change occurred from yield; usually occurs when #to_a is called + if result + repeated_field[i] = result if result != val + end + end + results + end + end + + + end + end +end |