X-Git-Url: https://git.distorted.org.uk/~mdw/lisp/blobdiff_plain/623291d25eb6f31558f252f037997549171b4d24..1a50efd8a9e976bf16a29ce381ea38c6b9a39ea1:/safely.lisp

diff --git a/safely.lisp b/safely.lisp
index 44a707e..9b4ab45 100644
--- a/safely.lisp
+++ b/safely.lisp
@@ -13,12 +13,12 @@
 ;;; it under the terms of the GNU General Public License as published by
 ;;; the Free Software Foundation; either version 2 of the License, or
 ;;; (at your option) any later version.
-;;; 
+;;;
 ;;; This program is distributed in the hope that it will be useful,
 ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 ;;; GNU General Public License for more details.
-;;; 
+;;;
 ;;; You should have received a copy of the GNU General Public License
 ;;; along with this program; if not, write to the Free Software Foundation,
 ;;; Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
@@ -30,6 +30,17 @@
 	   #:safely-writing))
 (in-package #:safely)
 
+#+(or cmu sbcl)
+(eval-when (:compile-toplevel :execute)
+  (import #+cmu '(ext:unix-namestring unix:unix-link)
+	  #+sbcl '(sb-ext:native-namestring)))
+#+cmu
+(progn
+  (declaim (inline unix-namestring))
+  (defun native-namestring (pathname &key as-file)
+    (declare (ignore as-file))
+    (unix-namestring pathname nil)))
+
 (defstruct (safely (:predicate safelyp))
   "Stores information about how to commit or undo safe writes."
   (streams nil)
@@ -99,6 +110,13 @@
 	  (safely-trail safe))
     stream))
 
+(declaim (inline rename))
+(defun rename (old new)
+  (let ((target (make-pathname :directory '(:relative)
+			       :defaults new)))
+    #-clisp (rename-file old target)
+    #+clisp (rename-file old target :if-exists :overwrite)))
+
 (defun delete-file-without-moaning (file)
   "Delete the FILE, ignoring errors."
   (handler-case (delete-file file)
@@ -107,7 +125,7 @@
 (defun rename-file-without-moaning (old new)
   "Rename OLD to NEW, ignoring errors, and without doing any stupid name
    mangling."
-  (handler-case (rename-file old new)
+  (handler-case (rename old new)
     (file-error () nil)))
 
 (defun safely-unwind (trail)
@@ -136,19 +154,34 @@
   (safely-unwind (safely-trail safe))
   (safely-reset safe))
 
+#+sbcl
+(defun unix-link (from to)
+  (sb-unix::int-syscall ("link" sb-alien:c-string sb-alien:c-string)
+			from to))
+
 (defun safe-copy (file tag)
   "Make a copy of the FILE.  Return the new name."
 
-  #+cmu
+  #+(or cmu sbcl)
   ;; Use link(2) where available.
   (generate-fresh-file-name file tag
 			    (lambda (name)
-			      (let ((from (ext:unix-namestring file t))
-				    (to (ext:unix-namestring name nil)))
+			      (let ((from (native-namestring file
+							     :as-file t))
+				    (to (native-namestring name
+							   :as-file t)))
 				(and from to
-				     (unix:unix-link from to)))))
+				     (unix-link from to)))))
 
-  #-cmu
+  #+clisp
+  (generate-fresh-file-name file tag
+			    (lambda (name)
+			      (posix:copy-file (namestring file)
+					       (namestring name)
+					       :method :hardlink
+					       :if-exists nil)))
+
+  #-(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
@@ -171,7 +204,7 @@
 		   (when (< read (length buffer))
 		     (return copy))))))
 	(close output)))))
-					      
+
 (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
@@ -187,23 +220,23 @@
 	  (loop
 	    (unless trail
 	      (return))
-	      (let ((job (pop trail)))
-		(ecase (car job)
-		  (:shunt (destructuring-bind (tag new file) job
-			    (declare (ignore tag))
-			    (push `(:rmtmp ,new) revert)
-			    (if (probe-file file)
-				(let ((old (safe-copy file "old")))
-				  (push `(:rmtmp ,old) cleanup)
-				  (push `(:revert ,old ,file) revert))
-				(push `(:rmtmp ,file) revert))
-			    (rename-file new file)))
-		  (:delete (destructuring-bind (tag file) job
-			     (declare (ignore tag))
-			     (let ((old (safe-copy file "delete")))
-			       (push `(:revert ,old ,file) revert)
-			       (push `(:rmtmp ,old) cleanup)
-			       (delete-file file)))))))
+	    (let ((job (pop trail)))
+	      (ecase (car job)
+		(:shunt (destructuring-bind (tag new file) job
+			  (declare (ignore tag))
+			  (push `(:rmtmp ,new) revert)
+			  (if (probe-file file)
+			      (let ((old (safe-copy file "old")))
+				(push `(:rmtmp ,old) cleanup)
+				(push `(:revert ,old ,file) revert))
+			      (push `(:rmtmp ,file) revert))
+			  (rename new file)))
+		(:delete (destructuring-bind (tag file) job
+			   (declare (ignore tag))
+			   (let ((old (safe-copy file "delete")))
+			     (push `(:revert ,old ,file) revert)
+			     (push `(:rmtmp ,old) cleanup)
+			     (delete-file file)))))))
 	  (setf revert nil))
       (safely-unwind trail)
       (safely-unwind revert)
@@ -227,8 +260,7 @@
    temporary file, and if BODY completes, it is renamed to FILE."
   (with-gensyms safe
     `(safely (,safe)
-       (let ((,stream (apply #'safely-open-output-stream
-			     ,safe ,file ,open-args)))
+       (let ((,stream (safely-open-output-stream ,safe ,file ,@open-args)))
 	 ,@body))))
 
 ;;;----- That's all, folks --------------------------------------------------