1 files changed, 57 insertions, 0 deletions
diff --git a/db-db2/foreign-resources.lisp b/db-db2/foreign-resources.lisp
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+;;;; -*- Mode: LISP; Syntax: ANSI-Common-Lisp; Base: 10 -*-
+;;;; *************************************************************************
+;;;; FILE IDENTIFICATION
+;;;;
+;;;; This file is part of CLSQL.
+;;;;
+;;;; CLSQL users are granted the rights to distribute and use this software
+;;;; as governed by the terms of the Lisp Lesser GNU Public License
+;;;; (http://opensource.franz.com/preamble.html), also known as the LLGPL.
+;;;; *************************************************************************
+
+(in-package #:clsql-db2)
+
+(defparameter *foreign-resource-hash* (make-hash-table :test #'equal))
+
+(defstruct (foreign-resource)
+  (type (error "Missing TYPE.")
+        :read-only t)
+  (sizeof (error "Missing SIZEOF.")
+          :read-only t)
+  (buffer (error "Missing BUFFER.")
+          :read-only t)
+  (in-use nil :type boolean))
+
+
+(defun %get-resource (type sizeof)
+  (let ((resources (gethash type *foreign-resource-hash*)))
+    (car (member-if
+          #'(lambda (res)
+              (and (= (foreign-resource-sizeof res) sizeof)
+                   (not (foreign-resource-in-use res))))
+          resources))))
+
+(defun %insert-foreign-resource (type res)
+  (let ((resource (gethash type *foreign-resource-hash*)))
+    (setf (gethash type *foreign-resource-hash*)
+          (cons res resource))))
+
+(defmacro acquire-foreign-resource (type &optional size)
+  `(let ((res (%get-resource ,type ,size)))
+     (unless res
+       (setf res (make-foreign-resource
+                  :type ,type :sizeof ,size
+                  :buffer (uffi:allocate-foreign-object ,type ,size)))
+       (%insert-foreign-resource ',type res))
+     (claim-foreign-resource res)))
+
+(defun free-foreign-resource (ares)
+  (setf (foreign-resource-in-use ares) nil)
+  ares)
+
+(defun claim-foreign-resource (ares)
+  (setf (foreign-resource-in-use ares) t)
+  ares)
+
+
+