Added the batcher class.

sunspot/lib/sunspot/batcher.rb

@@ -0,0 +1,76 @@
+module Sunspot
+
+  #
+  # Keeps a stack of batches and helps out when Indexer is asked to batch documents.
+  #
+  # If the client does something like 
+  #   
+  #   Sunspot.batch do
+  #     some_code_here
+  #     which_triggers_some_other_code
+  #     which_again_calls
+  #     Sunspot.batch { ... }
+  #   end
+  #
+  # it is the Batcher's job to keep track of these nestings. The inner will
+  # be sent of to be indexed first.
+  #
+  class Batcher
+    include Enumerable
+
+    # Raised if you ask to end current, but no current exists
+    class NoCurrentBatchError < StandardError; end
+
+
+    def initialize
+      @stack = []
+    end
+
+
+
+    def current
+      stack.last or start_new
+    end
+
+    def start_new
+      (stack << []).last
+    end
+
+    def end_current
+      fail NoCurrentBatchError if stack.empty?
+
+      stack.pop
+    end
+
+
+
+    def depth
+      stack.length
+    end
+
+    def batching?
+      depth > 0
+    end
+
+
+
+    def each
+      current.each { |v| yield v }
+    end
+
+    def push(value)
+      current << value
+    end
+    alias << push
+
+    def concat(values)
+      current.concat values
+    end
+
+
+
+    private
+
+    attr_reader :stack
+  end
+end

sunspot/lib/sunspot/indexer.rb

@@ -1,3 +1,5 @@
+require 'sunspot/batcher'
+
 module Sunspot
   # 
   # This class presents a service for adding, updating, and removing data

sunspot/spec/api/batcher_spec.rb

@@ -0,0 +1,112 @@
+require File.expand_path('spec_helper', File.dirname(__FILE__))
+
+describe Sunspot::Batcher do
+  it "includes Enumerable" do
+    described_class.should include Enumerable
+  end
+
+  describe "#each" do
+    let(:current) { [:foo, :bar] }
+    before { subject.stub(:current).and_return current }
+
+    it "iterates over current" do
+      yielded_values = []
+
+      subject.each do |value|
+        yielded_values << value
+      end
+
+      yielded_values.should eq current
+    end
+  end
+
+  describe "adding to current batch" do
+    it "#push pushes to current" do
+      subject.push :foo
+      subject.current.should include :foo
+    end
+
+    it "#<< pushes to current" do
+      subject.push :foo
+      subject.current.should include :foo
+    end
+
+    it "#concat concatinates on current batch" do
+      subject << :foo
+      subject.concat [:bar, :mix]
+      should include :foo, :bar, :mix
+    end
+  end
+
+
+  describe "#current" do
+    context "no current" do
+      it "starts a new" do
+        expect { subject.current }.to change(subject, :depth).by 1
+      end
+
+      it "is empty by default" do
+        subject.current.should be_empty
+      end
+    end
+
+    context "with a current" do
+      before { subject.start_new }
+
+      it "does not start a new" do
+        expect { subject.current }.to_not change(subject, :depth)
+      end
+
+      it "returns the same as last time" do
+        subject.current.should eq subject.current
+      end
+    end
+  end
+
+  describe "#start_new" do
+    it "creates a new batches" do
+      expect { 2.times { subject.start_new } }.to change(subject, :depth).by 2
+    end
+
+    it "changes current" do
+      subject << :foo
+      subject.start_new
+      should_not include :foo
+    end
+  end
+
+  describe "#end_current" do
+    context "no current batch" do
+      it "fails" do
+        expect { subject.end_current }.to raise_error Sunspot::Batcher::NoCurrentBatchError
+      end
+    end
+
+    context "with current batch" do
+      before { subject.start_new }
+
+      it "changes current" do
+        subject << :foo
+        subject.end_current
+        should_not include :foo
+      end
+
+      it "returns current" do
+        subject << :foo
+        subject.end_current.should include :foo
+      end
+    end
+  end
+
+  describe "#batching?" do
+    it "is false when depth is 0" do
+      subject.should_receive(:depth).and_return 0
+      should_not be_batching
+    end
+
+    it "is true when depth is more than 0" do
+      subject.should_receive(:depth).and_return 1
+      should be_batching
+    end
+  end
+end