#: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)
(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)
(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)
(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)))))
+
+ #+clisp
+ (generate-fresh-file-name file tag
+ (lambda (name)
+ (posix:copy-file (namestring file)
+ (namestring name)
+ :method :hardlink
+ :if-exists nil)))
+
+
- #-cmu
+ #-(or cmu sbcl)
;; Otherwise just copy the file contents and hope for the best.
(with-open-file (input file :element-type :default)
(multiple-value-bind
(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)
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 --------------------------------------------------