X-Git-Url: https://git.distorted.org.uk/~mdw/lisp/blobdiff_plain/562ed2ddc451abe9be0ec5bb9684b2df56942d8f..813da880d2d77f04ea623f426d543d298528f967:/safely.lisp

diff --git a/safely.lisp b/safely.lisp
index 9809f07..9b39518 100644
--- a/safely.lisp
+++ b/safely.lisp
@@ -1,7 +1,5 @@
 ;;; -*-lisp-*-
 ;;;
-;;; $Id$
-;;;
 ;;; Safely modify collections of files
 ;;;
 ;;; (c) 2005 Straylight/Edgeware
@@ -24,10 +22,7 @@
 ;;; Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 
 (defpackage #:safely
-  (:use #:common-lisp #:mdw.base)
-  (:export #:safely #:safely-close #:safely-delete-file
-	   #:safely-open-output-stream #:safely-bail #:safely-commit
-	   #:safely-writing))
+  (:use #:common-lisp #:mdw.base))
 (in-package #:safely)
 
 #+(or cmu sbcl)
@@ -41,15 +36,18 @@
     (declare (ignore as-file))
     (unix-namestring pathname nil)))
 
-(defstruct (safely (:predicate safelyp))
+(export '(safely safelyp make-safely))
+(defstruct (safely (:predicate safelyp) (:constructor make-safely ()))
   "Stores information about how to commit or undo safe writes."
   (streams nil)
   (trail nil))
 
+(export 'safely-close)
 (defun safely-close (safe stream)
   "Make sure that STREAM is closed when SAFE is finished."
   (push stream (safely-streams safe)))
 
+(export 'safely-delete-file)
 (defun safely-delete-file (safe file)
   "Delete FILE when SAFE is committed."
   (push `(:delete ,file) (safely-trail safe)))
@@ -94,6 +92,7 @@
 	(when ret
 	  (return (values new ret)))))))
 
+(export 'safely-open-output-stream)
 (defun safely-open-output-stream (safe file &rest open-args)
   "Create an output stream which will be named FILE when SAFE is committed.
    Other OPEN-ARGS are passed to open."
@@ -110,12 +109,26 @@
 	  (safely-trail safe))
     stream))
 
+#+clisp
+(progn
+  (ffi:def-call-out %rename (:name "rename")
+    (:language :stdc)
+    (:library "libc.so.6")
+    (:arguments (from ffi:c-string)
+		(to ffi:c-string))
+    (:return-type ffi:int)))
+
 (declaim (inline rename))
 (defun rename (old new)
+  #-clisp
   (let ((target (make-pathname :directory '(:relative)
 			       :defaults new)))
-    #-clisp (rename-file old target)
-    #+clisp (rename-file old target :if-exists :overwrite)))
+    (rename-file old target))
+
+  #+clisp
+  (let ((rc (%rename (namestring old) (namestring new))))
+    (when (= rc -1)
+      (error "Failed to rename ~S to ~S: ~A" old new (posix:strerror)))))
 
 (defun delete-file-without-moaning (file)
   "Delete the FILE, ignoring errors."
@@ -146,6 +159,7 @@
   (setf (safely-streams safe) nil)
   (setf (safely-trail safe) nil))
 
+(export 'safely-bail)
 (defun safely-bail (safe)
   "Abort the operations in SAFE, unwinding all the things that have been
    done.  Streams are closed, new files are removed."
@@ -181,9 +195,7 @@
 					       :method :hardlink
 					       :if-exists nil)))
 
-
-
-  #-(or cmu sbcl)
+  #-(or cmu sbcl clisp)
   ;; Otherwise just copy the file contents and hope for the best.
   (with-open-file (input file :element-type :default)
     (multiple-value-bind
@@ -207,6 +219,7 @@
 		     (return copy))))))
 	(close output)))))
 
+(export 'safely-commit)
 (defun safely-commit (safe)
   "Commit SAFE.  The files deleted by safely-delete-file are deleted; the
    files created by safely-open-output-stream are renamed over the old
@@ -245,6 +258,7 @@
       (safely-unwind cleanup)
       (safely-reset safe))))
 
+;; The symbol `safely' is already exported.
 (defmacro safely ((safe &key) &body body)
   "Do stuff within the BODY safely.  If BODY completes without errors, the
    SAFE is committed; otherwise it's bailed."
@@ -257,6 +271,7 @@
        (when ,safe
 	 (safely-bail ,safe)))))
 
+(export 'safely-writing)
 (defmacro safely-writing ((stream file &rest open-args) &body body)
   "Simple macro for writing a single file safely.  STREAM is opened onto a
    temporary file, and if BODY completes, it is renamed to FILE."