From 103a53263d1aac970157ad356116f4db32451f5a Mon Sep 17 00:00:00 2001
From: Eitaro Fukamachi <e.arrows@gmail.com>
Date: Thu, 15 Aug 2024 13:48:24 +0000
Subject: [PATCH] Add 'close-cursor' to delete a declared cursor explicitly.

---
 src/dbd/postgres.lisp |  7 +++++++
 src/driver.lisp       | 11 +++++++++++
 t/dbd/postgres.lisp   |  7 +++++--
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/dbd/postgres.lisp b/src/dbd/postgres.lisp
index 355027c..bb1f590 100644
--- a/src/dbd/postgres.lisp
+++ b/src/dbd/postgres.lisp
@@ -133,6 +133,13 @@
                  :connection conn
                  :sql sql))
 
+(defmethod close-cursor-using-connection ((conn dbd-postgres-connection) (cursor dbi-cursor))
+  (when (cursor-declared-p cursor)
+    (exec-query (connection-handle conn)
+                (format nil "CLOSE ~A" (cursor-name cursor)))
+    (setf (cursor-declared-p cursor) nil)
+    t))
+
 (defmethod execute-using-connection ((conn dbd-postgres-connection) (cursor dbi-cursor) params)
   (assert (in-transaction conn))
   (with-accessors ((sql query-sql)
diff --git a/src/driver.lisp b/src/driver.lisp
index edf2f02..2e55c2b 100644
--- a/src/driver.lisp
+++ b/src/driver.lisp
@@ -32,6 +32,8 @@
            #:cursor-formatter
            #:cursor-declared-p
            #:make-cursor
+           #:close-cursor
+           #:close-cursor-using-connection
            #:prepare
            #:prepare-cached
            #:execute
@@ -183,6 +185,10 @@ This method may be overrided by subclasses."
     (error 'dbi-unimplemented-error
            :method-name 'make-cursor)))
 
+(defgeneric close-cursor (cursor)
+  (:method ((cursor dbi-cursor))
+    (close-cursor-using-connection (dbi-connection cursor) cursor)))
+
 (defgeneric execute (query &optional params)
   (:documentation "Execute `query` with `params` and return the results.")
   (:method (object &optional params)
@@ -271,6 +277,11 @@ This method must be implemented in each drivers.")
     (error 'dbi-unimplemented-error
            :method-name 'execute-using-connection)))
 
+(defgeneric close-cursor-using-connection (conn cursor)
+  (:method (conn cursor)
+    (declare (ignore conn cursor))
+    (error 'dbi-unimplemented-error
+           :method-name 'close-cursor-using-connection)))
 
 (defgeneric begin-transaction (conn)
   (:documentation "Start a transaction.")
diff --git a/t/dbd/postgres.lisp b/t/dbd/postgres.lisp
index ec7f8b3..e4e2958 100644
--- a/t/dbd/postgres.lisp
+++ b/t/dbd/postgres.lisp
@@ -7,6 +7,7 @@
                 #:do-sql
                 #:with-transaction
                 #:make-cursor
+                #:close-cursor
                 #:execute
                 #:fetch))
 (in-package #:dbd-postgres-test)
@@ -38,8 +39,10 @@
               (make-cursor conn "SELECT * FROM person")))
         (execute cursor)
         (ok (equal (getf (fetch cursor) :|name|) "Woody"))
-        (ok (equal (getf (fetch cursor) :|name|) "Buzz"))))
+        (ok (equal (getf (fetch cursor) :|name|) "Buzz"))
+        (close-cursor cursor)))
     (with-transaction conn
       (let ((cursor (make-cursor conn "SELECT * FROM person WHERE name = 'Trixie'")))
         (execute cursor)
-        (ok (null (fetch cursor)))))))
+        (ok (null (fetch cursor)))
+        (close-cursor cursor)))))