From 91308cdc6007433b8e4ff1ac9f127ebe70d3fb2c Mon Sep 17 00:00:00 2001
From: Kyle Banker <kylebanker@gmail.com>
Date: Fri, 5 Aug 2011 17:51:37 -0400
Subject: [PATCH] RUBY-167 Cursor#alive?

---
 lib/mongo/cursor.rb | 12 ++++++++++++
 test/cursor_test.rb | 16 ++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/lib/mongo/cursor.rb b/lib/mongo/cursor.rb
index 4179c2c..2d31add 100644
--- a/lib/mongo/cursor.rb
+++ b/lib/mongo/cursor.rb
@@ -93,6 +93,18 @@ module Mongo
       end
     end
 
+    # Guess whether the cursor is alive on the server.
+    #
+    # Note that this method only checks whether we have
+    # a cursor id. The cursor may still have timed out
+    # on the server. This will be indicated in the next
+    # call to Cursor#next_document.
+    #
+    # @return [Boolean]
+    def alive?
+      @cursor_id && @cursor_id != 0
+    end
+
     # Get the next document specified the cursor options.
     #
     # @return [Hash, Nil] the next document or Nil if no documents remain.
diff --git a/test/cursor_test.rb b/test/cursor_test.rb
index b06b58d..8ed4989 100644
--- a/test/cursor_test.rb
+++ b/test/cursor_test.rb
@@ -16,6 +16,22 @@ class CursorTest < Test::Unit::TestCase
     @@coll_full_name = "#{MONGO_TEST_DB}.test"
   end
 
+  def test_alive
+    batch = []
+    5000.times do |n|
+      batch << {:a => n}
+    end
+
+    @@coll.insert(batch)
+    cursor = @@coll.find
+    assert !cursor.alive?
+    cursor.next
+    assert cursor.alive?
+    cursor.close
+    assert !cursor.alive?
+    @@coll.remove
+  end
+
   def test_add_options
     c = @@coll.find
     c.add_option(OP_QUERY_EXHAUST)