add instrumentation to detection and classification

lib/linguist.rb

@@ -6,3 +6,15 @@ require 'linguist/repository'
 require 'linguist/samples'
 require 'linguist/shebang'
 require 'linguist/version'
+
+class << Linguist
+  attr_accessor :instrumenter
+
+  def instrument(*args, &bk)
+    if instrumenter
+      instrumenter.instrument(*args, &bk)
+    else
+      yield
+    end
+  end
+end

lib/linguist/classifier.rb

@@ -16,11 +16,13 @@ module Linguist
     #
     # Returns an Array of Language objects, most probable first.
     def self.call(blob, possible_languages)
+      Linguist.instrument("linguist.bayesian_classification") do
         language_names = possible_languages.map(&:name)
         classify(Samples.cache, blob.data, language_names).map do |name, _|
           Language[name] # Return the actual Language objects
         end
       end
+    end
 
     # Public: Train classifier that data is a certain language.
     #

lib/linguist/language.rb

@@ -105,6 +105,7 @@ module Linguist
       # Bail early if the blob is binary or empty.
       return nil if blob.likely_binary? || blob.binary? || blob.empty?
 
+      Linguist.instrument("linguist.detection") do
         # Call each strategy until one candidate is returned.
         STRATEGIES.reduce([]) do |languages, strategy|
           candidates = strategy.call(blob, languages)
@@ -119,6 +120,7 @@ module Linguist
           end
         end.first
       end
+    end
 
     # Public: Get all Languages
     #