From caf2676aad25fb3a6e516fa6daaafdc376e38c79 Mon Sep 17 00:00:00 2001
From: "Brian J. Cardiff" <bcardiff@manas.com.ar>
Date: Fri, 29 Jan 2016 21:57:00 -0300
Subject: [PATCH] column_count and column_names close result_set and statements
 main entry points for exec_non_query and exec_query closing them when ready

---
 spec/std/db/dummy_driver.cr |  8 ++++++++
 src/db/database.cr          | 23 +++++++++++++++++++++++
 src/db/result_set.cr        |  9 +++++++++
 src/db/statement.cr         | 16 ++++++++++++++++
 4 files changed, 56 insertions(+)

diff --git a/spec/std/db/dummy_driver.cr b/spec/std/db/dummy_driver.cr
index 9b9b5d9..24b76c0 100644
--- a/spec/std/db/dummy_driver.cr
+++ b/spec/std/db/dummy_driver.cr
@@ -40,6 +40,14 @@ class DummyDriver < DB::Driver
       end
     end
 
+    def column_count
+      2
+    end
+
+    def column_name(index)
+      "c#{index}"
+    end
+
     private def read? : DB::Any?
       n = @values.not_nil!.next
       raise "end of row" if n.is_a?(Iterator::Stop)
diff --git a/src/db/database.cr b/src/db/database.cr
index 25a171f..3d8641d 100644
--- a/src/db/database.cr
+++ b/src/db/database.cr
@@ -9,12 +9,35 @@ module DB
       @driver = @driver_class.new(@options)
     end
 
+    # :nodoc:
     def prepare(query)
       @driver.prepare(query)
     end
 
+    # :nodoc:
     def exec(query, *args)
       prepare(query).exec(*args)
     end
+
+    def exec_non_query(query, *args)
+      exec_query(query) do |result_set|
+        result_set.move_next
+      end
+    end
+
+    # :nodoc:
+    def exec_query(query, *args)
+      result_set = exec(query, *args)
+      yield result_set
+      result_set.close
+    end
+
+    def exec_query_each(query, *args)
+      exec_query(query) do |result_set|
+        result_set.each do
+          yield result_set
+        end
+      end
+    end
   end
 end
diff --git a/src/db/result_set.cr b/src/db/result_set.cr
index ed396c5..4958fc7 100644
--- a/src/db/result_set.cr
+++ b/src/db/result_set.cr
@@ -11,8 +11,17 @@ module DB
       end
     end
 
+    def close
+      @statement.close
+    end
+
     abstract def move_next : Bool
 
+    abstract def column_count : Int32
+    abstract def column_name(index : Int32) : String
+
+    # abstract def column_type(index : Int32)
+
     # list datatypes that must be supported form the driver
     # users will call read(String) or read?(String) for nillables
     {% for t in DB::TYPES %}
diff --git a/src/db/statement.cr b/src/db/statement.cr
index 30f2440..a5e58ca 100644
--- a/src/db/statement.cr
+++ b/src/db/statement.cr
@@ -3,6 +3,7 @@ module DB
     getter driver
 
     def initialize(@driver)
+      @closed = false
     end
 
     def exec(*args) : ResultSet
@@ -32,9 +33,24 @@ module DB
     protected def before_execute
     end
 
+    # Closes this statement.
+    def close
+      raise "Statement already closed" if @closed
+      @closed = true
+      on_close
+    end
+
+    # Returns `true` if this statement is closed. See `#close`.
+    def closed?
+      @closed
+    end
+
     # 1-based positional arguments
     protected abstract def add_parameter(index : Int32, value)
     protected abstract def add_parameter(name : String, value)
+
     protected abstract def execute : ResultSet
+    protected def on_close
+    end
   end
 end