Move Samples::DATA constant to Samples.cache method

Rakefile

@@ -99,7 +99,7 @@ namespace :classifier do
       next if file_language.nil? || file_language == 'Text'
       begin
         data = open(file_url).read
-        guessed_language, score = Linguist::Classifier.classify(Linguist::Samples::DATA, data).first
+        guessed_language, score = Linguist::Classifier.classify(Linguist::Samples.cache, data).first
 
         total += 1
         guessed_language == file_language ? correct += 1 : incorrect += 1

lib/linguist/language.rb

@@ -136,7 +136,7 @@ module Linguist
         elsif (determined = Heuristics.find_by_heuristics(data, possible_language_names)) && !determined.empty?
           determined.first
         # Lastly, fall back to the probabilistic classifier.
-        elsif classified = Classifier.classify(Samples::DATA, data, possible_language_names).first
+        elsif classified = Classifier.classify(Samples.cache, data, possible_language_names).first
           # Return the actual Language object based of the string language name (i.e., first element of `#classify`)
           Language[classified[0]]
         end
@@ -510,9 +510,9 @@ module Linguist
     end
   end
 
-  extensions = Samples::DATA['extnames']
-  interpreters = Samples::DATA['interpreters']
-  filenames = Samples::DATA['filenames']
+  extensions = Samples.cache['extnames']
+  interpreters = Samples.cache['interpreters']
+  filenames = Samples.cache['filenames']
   popular = YAML.load_file(File.expand_path("../popular.yml", __FILE__))
 
   languages_yml = File.expand_path("../languages.yml", __FILE__)

lib/linguist/samples.rb

@@ -17,9 +17,11 @@ module Linguist
     PATH = File.expand_path('../samples.json', __FILE__)
 
     # Hash of serialized samples object
-    if File.exist?(PATH)
+    def self.cache
+      @cache ||= begin
         serializer = defined?(JSON) ? JSON : YAML
-      DATA = serializer.load(File.read(PATH))
+        serializer.load(File.read(PATH))
+      end
     end
 
     # Public: Iterate over each sample.

test/test_classifier.rb

@@ -44,12 +44,12 @@ class TestClassifier < Test::Unit::TestCase
   end
 
   def test_instance_classify_empty
-    results = Classifier.classify(Samples::DATA, "")
+    results = Classifier.classify(Samples.cache, "")
     assert results.first[1] < 0.5, results.first.inspect
   end
 
   def test_instance_classify_nil
-    assert_equal [], Classifier.classify(Samples::DATA, nil)
+    assert_equal [], Classifier.classify(Samples.cache, nil)
   end
 
   def test_classify_ambiguous_languages
@@ -58,7 +58,7 @@ class TestClassifier < Test::Unit::TestCase
       languages = Language.find_by_filename(sample[:path]).map(&:name)
       next unless languages.length > 1
 
-      results = Classifier.classify(Samples::DATA, File.read(sample[:path]), languages)
+      results = Classifier.classify(Samples.cache, File.read(sample[:path]), languages)
       assert_equal language.name, results.first[0], "#{sample[:path]}\n#{results.inspect}"
     end
   end

test/test_samples.rb

@@ -8,7 +8,7 @@ class TestSamples < Test::Unit::TestCase
   include Linguist
 
   def test_up_to_date
-    assert serialized = Samples::DATA
+    assert serialized = Samples.cache
     assert latest = Samples.data
 
     # Just warn, it shouldn't scare people off by breaking the build.
@@ -29,7 +29,7 @@ class TestSamples < Test::Unit::TestCase
   end
 
   def test_verify
-    assert data = Samples::DATA
+    assert data = Samples.cache
 
     assert_equal data['languages_total'], data['languages'].inject(0) { |n, (_, c)| n += c }
     assert_equal data['tokens_total'], data['language_tokens'].inject(0) { |n, (_, c)| n += c }
@@ -38,7 +38,7 @@ class TestSamples < Test::Unit::TestCase
 
   # Check that there aren't samples with extensions that aren't explicitly defined in languages.yml
   def test_parity
-    extensions = Samples::DATA['extnames']
+    extensions = Samples.cache['extnames']
     languages_yml = File.expand_path("../../lib/linguist/languages.yml", __FILE__)
     languages = YAML.load_file(languages_yml)