From 73e119e1abe28a94ea476662b7fea68a94906060 Mon Sep 17 00:00:00 2001
From: Dan McClain <git@danseaver.com>
Date: Mon, 10 Sep 2012 14:17:38 -0400
Subject: [PATCH] Adds array overlap arel operator

---
 .../arel/nodes/contained_within.rb            |  5 +++++
 lib/postgres_ext/arel/predications.rb         |  4 ++++
 lib/postgres_ext/arel/visitors/to_sql.rb      | 17 +++++++++++++++
 spec/arel/array_spec.rb                       | 21 ++++++++++++++++++-
 4 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/lib/postgres_ext/arel/nodes/contained_within.rb b/lib/postgres_ext/arel/nodes/contained_within.rb
index d6c11d4..308caf6 100644
--- a/lib/postgres_ext/arel/nodes/contained_within.rb
+++ b/lib/postgres_ext/arel/nodes/contained_within.rb
@@ -10,5 +10,10 @@ class ArrayAnyEq < Arel::Nodes::Binary
       alias :operand1 :left
       alias :operand2 :right
     end
+
+    class ArrayOverlap < Arel::Nodes::Binary
+      alias :operand1 :left
+      alias :operand2 :right
+    end
   end
 end
diff --git a/lib/postgres_ext/arel/predications.rb b/lib/postgres_ext/arel/predications.rb
index cf23193..dcbdc8c 100644
--- a/lib/postgres_ext/arel/predications.rb
+++ b/lib/postgres_ext/arel/predications.rb
@@ -9,5 +9,9 @@ def contained_within(other)
     def array_any_eq(other)
       Nodes::ArrayAnyEq.new self, other
     end
+
+    def array_overlap(other)
+      Nodes::ArrayOverlap.new self, other
+    end
   end
 end
diff --git a/lib/postgres_ext/arel/visitors/to_sql.rb b/lib/postgres_ext/arel/visitors/to_sql.rb
index 338aa34..e7156ed 100644
--- a/lib/postgres_ext/arel/visitors/to_sql.rb
+++ b/lib/postgres_ext/arel/visitors/to_sql.rb
@@ -11,9 +11,26 @@ def visit_Arel_Nodes_ArrayAnyEq o
         "#{visit o.right} = ANY(#{visit o.left})"
       end
 
+      def visit_Arel_Nodes_ArrayOverlap o
+        if Array === o.right 
+          right = "{#{o.right.map{|v| change_string(visit(v))}.join(',')}}"
+          "#{visit o.left} && '#{right}'"
+        else
+          "#{visit o.left} && #{visit o.right}"
+        end
+      end
+
       def visit_IPAddr value
         "'#{value.to_s}/#{value.instance_variable_get(:@mask_addr).to_s(2).count('1')}'"
       end
+
+      def change_string value
+        if value.match /"|,|{/
+          value.gsub(/"/, "\"").gsub(/'/,'"')
+        else
+          value.gsub(/'/,'')
+        end
+      end
     end
   end
 end
diff --git a/spec/arel/array_spec.rb b/spec/arel/array_spec.rb
index c938e9e..412654b 100644
--- a/spec/arel/array_spec.rb
+++ b/spec/arel/array_spec.rb
@@ -18,7 +18,7 @@ class ArelArray < ActiveRecord::Base
     Object.send(:remove_const, :ArelArray)
   end
 
-  describe 'Array Any' do
+  describe 'Array Any Equal' do
     it 'converts Arel array_any_eq statement' do
       arel_table = ArelArray.arel_table
 
@@ -33,4 +33,23 @@ class ArelArray < ActiveRecord::Base
       ArelArray.where(arel_table[:tags].array_any_eq('one')).should include(one)
     end
   end
+
+  describe 'Array Overlap' do
+    it 'converts Arel array_overlap statment' do
+      arel_table = ArelArray.arel_table
+
+      arel_table.where(arel_table[:tags].array_overlap(['tag','tag 2'])).to_sql.should match /&& '\{tag,tag 2\}'/
+    end
+
+    it 'returns matched records' do
+      one = ArelArray.create!(:tags => ['one'])
+      two = ArelArray.create!(:tags => ['two'])
+      arel_table = ArelArray.arel_table
+
+      ArelArray.where(arel_table[:tags].array_overlap(['one'])).should include(one)
+      ArelArray.where(arel_table[:tags].array_overlap(['two'])).should include(two)
+      ArelArray.where(arel_table[:tags].array_overlap(['two','one'])).should include(two)
+      ArelArray.where(arel_table[:tags].array_overlap(['two','one'])).should include(one)
+    end
+  end
 end