X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/lisp/blobdiff_plain/443fcfc494ed940c60d94c70e3391bf3c79c915f..1a50efd8a9e976bf16a29ce381ea38c6b9a39ea1:/safely.lisp

diff --git a/safely.lisp b/safely.lisp
index 8cd0f9a..9b4ab45 100644
--- a/safely.lisp
+++ b/safely.lisp
@@ -33,7 +33,13 @@ (in-package #:safely)
 #+(or cmu sbcl)
 (eval-when (:compile-toplevel :execute)
   (import #+cmu '(ext:unix-namestring unix:unix-link)
-	  #+sbcl '(sb-int:unix-namestring)))
+	  #+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."
@@ -106,8 +112,10 @@ (defun safely-open-output-stream (safe file &rest open-args)
 
 (declaim (inline rename))
 (defun rename (old new)
-  #-clisp (rename-file old new)
-  #+clisp (posix:copy-file old new :method :rename))
+  (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."
@@ -158,20 +166,22 @@ (defun safe-copy (file tag)
   ;; Use link(2) where available.
   (generate-fresh-file-name file tag
 			    (lambda (name)
-			      (let ((from (unix-namestring file t))
-				    (to (unix-namestring name nil)))
+			      (let ((from (native-namestring file
+							     :as-file t))
+				    (to (native-namestring name
+							   :as-file t)))
 				(and from to
 				     (unix-link from to)))))
 
   #+clisp
   (generate-fresh-file-name file tag
 			    (lambda (name)
-			      (>= (unix:link (namestring file) 
-					     (namestring name))
-				  0)))
+			      (posix:copy-file (namestring file)
+					       (namestring name)
+					       :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
@@ -210,23 +220,23 @@ (defun safely-commit (safe)
 	  (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 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)