From b34681ce40d8ea8073ddcbda8c2e1048d5abaaf9 Mon Sep 17 00:00:00 2001
From: Seth Jeffery <seth@quipper.com>
Date: Fri, 24 Apr 2015 14:37:39 +0100
Subject: [PATCH] add support for index hinting

---
 lib/plucky/query.rb       |  5 +++++
 spec/plucky/query_spec.rb | 23 +++++++++++++++++++++++
 spec/plucky_spec.rb       |  2 +-
 3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/lib/plucky/query.rb b/lib/plucky/query.rb
index c0bb6a8..c7b0859 100755
--- a/lib/plucky/query.rb
+++ b/lib/plucky/query.rb
@@ -127,6 +127,11 @@ def fields(*args)
         clone.tap { |query| query.options[:fields] = *args }
       end
 
+      def hint(*fields)
+        hint_fields = fields.first.is_a?(Hash) ? fields.first : Hash[fields.map{|hint| [hint, 1]}]
+        clone.tap { |query| query.options[:hint] = hint_fields }
+      end
+
       def ignore(*args)
         set_field_inclusion(args, 0)
       end
diff --git a/spec/plucky/query_spec.rb b/spec/plucky/query_spec.rb
index 1a2b258..92d29dc 100755
--- a/spec/plucky/query_spec.rb
+++ b/spec/plucky/query_spec.rb
@@ -404,6 +404,29 @@
     end
   end
 
+  context "#hint" do
+    before  { @query = described_class.new(@collection) }
+    subject { @query }
+
+    it "works" do
+      subject.hint(:name, :age).
+        options[:hint].
+        should == { :name => 1, :age => 1 }
+    end
+
+    it "returns new instance of query" do
+      new_query = subject.hint(:name)
+      new_query.should_not equal(subject)
+      subject[:hint].should be_nil
+    end
+
+    it "works with hash" do
+      subject.hint(:name => 1, :_id => 1).
+        options[:hint].
+        should == { :name => 1, :_id => 1 }
+    end
+  end
+
   context "#ignore" do
     before  { @query = described_class.new(@collection) }
     subject { @query }
diff --git a/spec/plucky_spec.rb b/spec/plucky_spec.rb
index 08e780f..438836a 100644
--- a/spec/plucky_spec.rb
+++ b/spec/plucky_spec.rb
@@ -61,7 +61,7 @@
         :count, :size, :distinct,
         :last, :first, :all, :to_a,
         :exists?, :exist?, :empty?,
-        :remove,
+        :remove, :hint
       ].sort_by(&:to_s)
     end
   end