From: Mark Wooding <mdw@distorted.org.uk>
Date: Thu, 26 May 2016 08:26:09 +0000 (+0100)
Subject: src/c-types-impl.lisp (intern-c-type): Canonify class and initargs.
X-Git-Url: https://git.distorted.org.uk/~mdw/sod/commitdiff_plain/175d7ea7a7f768e7fea3ec62b5981c8fbb3ab164

src/c-types-impl.lisp (intern-c-type): Canonify class and initargs.

Make sure the class and initargs are canonical before probing the
`*c-type-intern-map*'.

  * The class should ideally be represented by name.

  * The initargs should be in ascending order by keyword name.

In particular, this fixes a bug where `qualify-c-type' erroneously
returns a fresh type when asked to attach an empty list of qualifiers to
an already-interned type.
---

diff --git a/src/c-types-impl.lisp b/src/c-types-impl.lisp
index a27b30f..9c503b4 100644
--- a/src/c-types-impl.lisp
+++ b/src/c-types-impl.lisp
@@ -35,7 +35,22 @@
 (defun intern-c-type (class &rest initargs)
   "If the CLASS and INITARGS have already been interned, then return the
    existing object; otherwise make a new one."
-  (let ((list (cons class initargs)))
+  (let ((list (cons (typecase class
+		      ;; Canonify the class object; we'd prefer a name.
+		      (standard-class (class-name class))
+		      (t class))
+		    (let ((alist nil) (plist initargs))
+		      ;; Canonify the initargs.  Arrange for them to be in
+		      ;; ascending order by name.  This is annoying because
+		      ;; a plist isn't a readily sortable sequence.
+		      (loop
+			(when (null plist) (return))
+			(let ((name (pop plist)) (value (pop plist)))
+			  (push (cons name value) alist)))
+		      (dolist (assoc (sort alist #'string> :key #'car))
+			(push (cdr assoc) plist)
+			(push (car assoc) plist))
+		      plist))))
     (or (gethash list *c-type-intern-map*)
 	(let ((new (apply #'make-instance class initargs)))
 	  (setf (gethash new *c-type-intern-map*) t