Sorting like Xcode. Fixes #615

CHANGELOG.md

@@ -4,7 +4,9 @@
 
 ##### Enhancements
 
-* None.  
+* Sort by name like Xcode does.  
+[Antoine Cœur](https://github.com/Coeur)
+[#677](https://github.com/CocoaPods/Xcodeproj/pull/677)
 
 ##### Bug Fixes
 

lib/xcodeproj/project/object/group.rb

@@ -1,5 +1,6 @@
 require 'xcodeproj/project/object/helpers/groupable_helper'
 require 'xcodeproj/project/object/helpers/file_references_factory'
+require 'xcodeproj/project/object/helpers/sort_helper'
 
 module Xcodeproj
   class Project
@@ -438,9 +439,9 @@ def sort(options = nil)
               end
             end
 
-            result = File.basename(x.display_name.downcase, '.*') <=> File.basename(y.display_name.downcase, '.*')
+            result = XcodeSortString.new(File.basename(x.display_name, '.*')) <=> XcodeSortString.new(File.basename(y.display_name, '.*'))
             if result.zero?
-              File.extname(x.display_name.downcase) <=> File.extname(y.display_name.downcase)
+              XcodeSortString.new(File.extname(x.display_name)) <=> XcodeSortString.new(File.extname(y.display_name))
             else
               result
             end

lib/xcodeproj/project/object/helpers/sort_helper.rb

@@ -0,0 +1,51 @@
+module Xcodeproj
+  # Wrapper for a string that sorts by name like Xcode does.
+  # @example
+  #   arrayOfFilenames.sort_by { |s| XcodeSortString.new(s) }
+  class XcodeSortString
+    include Comparable
+    attr_reader :str_fallback, :ints_and_strings, :ints_and_strings_fallback, :str_pattern
+
+    def initialize(str)
+      # fallback pass
+      @str_fallback = str
+      # first pass: digits are used as integers, symbols are individualized, case is ignored
+      @ints_and_strings = str.scan(/\d+|\p{L}+|[^\d\p{L}]/).map do |s|
+        case s
+        when /\d/ then Integer(s, 10)
+        else
+          if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('2.2.0')
+            s.unicode_normalize(:nfkd).gsub(/\p{Mn}/, '').downcase
+          else
+            s.downcase
+          end
+        end
+      end
+      # second pass: digits are inverted, case is inverted
+      @ints_and_strings_fallback = @str_fallback.scan(/\d+|\D+/).map do |s|
+        case s
+        when /\d/ then Integer(s.reverse, 10)
+        else s.swapcase
+        end
+      end
+      # comparing patterns: credit to https://rosettacode.org/wiki/Natural_sorting#Ruby
+      @str_pattern = @ints_and_strings.map { |el| el.is_a?(Integer) ? :i : :s }.join
+    end
+
+    def <=>(other)
+      if str_pattern.start_with?(other.str_pattern) || other.str_pattern.start_with?(str_pattern)
+        compare = ints_and_strings <=> other.ints_and_strings
+        if compare != 0
+          # we sort naturally (literal ints, symbols individualized, case ignored)
+          compare
+        else
+          # natural equality, we use the fallback sort (int reversed, case swapped)
+          ints_and_strings_fallback <=> other.ints_and_strings_fallback
+        end
+      else
+        # type mismatch, we sort alphabetically (case ignored)
+        str_fallback.downcase <=> other.str_fallback.downcase
+      end
+    end
+  end
+end

spec/project/object/helpers/sort_helper_spec.rb

@@ -0,0 +1,81 @@
+require File.expand_path('../../../../spec_helper', __FILE__)
+
+module ProjectSpecs
+  describe Xcodeproj::XcodeSortString do
+    before do
+      @helper = XcodeSortString
+    end
+
+    #-------------------------------------------------------------------------#
+
+    describe 'In general' do
+      it 'sorts names like Xcode' do
+        # Let's note that Xcode 10.2 on macOS 10.14.5 does not have a strong ordering
+        # when sorting unicode characters that transliterate to the same ascii characters
+        # so our unicode tests can stay rudimentary until Xcode is fixed for that.
+        # [rdar://50854433](http://www.openradar.me/radar?id=5012044621283328)
+        unsorted_names = [
+          # spaces comparison
+          ' a', '  a', 'a ', 'a  b', 'a a',
+          # dots comparison
+          '.a', '..a', 'a.', '1.',
+          # basic mix
+          '1a', '2 a', 'a1', 'a 2',
+          # pure integers
+          '1', '2', '10', '01',
+          # multi integers
+          '0.1.1', '0.1.2', '0.1.10', '0.1.01',
+          # multi equal integers
+          'A1B001', 'A01B1',
+          # case comparison
+          'A', 'a'
+        ]
+        if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('2.2.0')
+          unsorted_names += [
+            # unicode
+            'ffi ', 'ffh ', 'ffj '
+          ]
+        end
+        sorted = unsorted_names.sort_by { |s| @helper.new(s) }
+        # order given by Xcode 10.2 "Sort by Name" on macOS 10.14.5 (ruby 2.3.7p456), English as primary language
+        should = [
+          '  a',
+          ' a',
+          '..a',
+          '.a',
+          '0.1.1',
+          '0.1.01',
+          '0.1.2',
+          '0.1.10',
+          '1',
+          '01',
+          '1.',
+          '1a',
+          '2',
+          '2 a',
+          '10',
+          'a',
+          'A',
+          'a ',
+          'a  b',
+          'a 2',
+          'a a',
+          'a.',
+          'a1',
+          'A1B001',
+          'A01B1',
+        ]
+        if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('2.2.0')
+          should += [
+            'ffh ',
+            'ffi ',
+            'ffj ',
+          ]
+        end
+        sorted.should == should
+      end
+    end
+
+    #-------------------------------------------------------------------------#
+  end
+end