Merge 4444e71 into c8938c9

lib/bugsnag.rb

@@ -17,6 +17,8 @@
 # as it doesn't auto-configure when loaded
 require "bugsnag/integrations/rack"
 
+require "bugsnag/utility/circular_buffer"
+
 require "bugsnag/middleware/rack_request"
 require "bugsnag/middleware/warden_user"
 require "bugsnag/middleware/clearance_user"

lib/bugsnag/utility/circular_buffer.rb

@@ -0,0 +1,34 @@
+module Bugsnag::Utility
+  class CircularBuffer
+    include Enumerable
+
+    attr_reader :max_items
+
+    def initialize(max_items=25)
+      @max_items = max_items
+      @buffer = []
+    end
+
+    def <<(item)
+      @buffer << item
+      trim_buffer
+      self
+    end
+
+    def each(&block)
+      @buffer.each(&block)
+    end
+
+    def max_items=(new_max_items)
+      @max_items = new_max_items
+      trim_buffer
+    end
+
+    private
+    def trim_buffer
+        trim_size = @buffer.size - @max_items
+        trim_size = 0 if trim_size < 0
+        @buffer.shift(trim_size)
+    end
+  end
+end

spec/utility/circular_buffer_spec.rb

@@ -0,0 +1,91 @@
+# encoding: utf-8
+
+require 'spec_helper'
+
+describe Bugsnag::Utility::CircularBuffer do
+  describe "buffer size" do
+    it "should be 25 by default" do
+      buffer = Bugsnag::Utility::CircularBuffer.new
+
+      expect(buffer.max_items).to equal 25
+    end
+
+    it "can be set during initialization" do
+      buffer = Bugsnag::Utility::CircularBuffer.new(10)
+
+      expect(buffer.max_items).to equal 10
+    end
+
+    it "can be changed using max_items =" do
+      buffer = Bugsnag::Utility::CircularBuffer.new(10)
+      buffer.max_items = 17
+
+      expect(buffer.max_items).to equal(17)
+    end
+  end
+
+  describe "buffer items" do
+    it "initializes empty <<" do
+      buffer = Bugsnag::Utility::CircularBuffer.new
+
+      expect(buffer.to_a).to eq([])
+    end
+
+    it "can be added to with <<" do
+      buffer = Bugsnag::Utility::CircularBuffer.new
+      buffer << 1
+      expect(buffer.to_a).to eq([1])
+    end
+
+    it "are shifted when max_items are exceeded" do
+      buffer = Bugsnag::Utility::CircularBuffer.new(5)
+      (0...10).each { |x| buffer << x }
+
+      expect(buffer.to_a).to eq([5, 6, 7, 8, 9])
+    end
+
+    it "are removed if max_items is reduced" do
+      buffer = Bugsnag::Utility::CircularBuffer.new(10)
+      (0...10).each { |x| buffer << x }
+      buffer.max_items = 3
+
+      expect(buffer.to_a).to eq([7, 8, 9])
+    end
+
+    it "can be inserted in chains" do
+      buffer = Bugsnag::Utility::CircularBuffer.new
+      buffer << 1 << 2 << 3 << 4 << 5
+
+      expect(buffer.to_a).to eq([1, 2, 3, 4, 5])
+    end
+
+    it "can be iterated over" do
+      buffer = Bugsnag::Utility::CircularBuffer.new
+      buffer << 1
+      buffer << 2
+      buffer << 3
+
+      output = []
+      buffer.each do |x|
+        output << x
+      end
+
+      expect(output).to eq([1, 2, 3])
+    end
+
+    it "respects max_items when increased" do
+      buffer = Bugsnag::Utility::CircularBuffer.new(3)
+      buffer << 1
+      buffer << 2
+      buffer << 3
+
+      expect(buffer.to_a).to eq([1, 2, 3])
+
+      buffer.max_items = 5
+      buffer << 4
+      buffer << 5
+
+      expect(buffer.to_a).to eq([1, 2, 3, 4, 5])
+    end
+  end
+end