diff options
| -rw-r--r-- | flash.lisp | 49 |
1 files changed, 29 insertions, 20 deletions
@@ -4,6 +4,8 @@ (defvar *flashes* (make-hash-table :test #'equal :synchronized t)) +(defvar *flash-lock* + (bt:make-lock "flash lock")) (defparameter +flash-cookie-name+ "DNDFLASHKEY") (defparameter +flash-value-lifetime+ 10 @@ -26,14 +28,17 @@ expires." (let* ((key (or (lzb:request-cookie +flash-cookie-name+) (nuid))) (now - (get-universal-time)) - (entry - (or (gethash key *flashes*) - (make-flash-entry)))) - ;; update the entry - (setf (flash-entry-timestamp entry) now - (getf (flash-entry-table entry) label) value - (gethash key *flashes*) entry) + (get-universal-time))) + ;; holdign a lock here b/c I do stuff in between getting an entry + ;; and writing to it. + (bt:with-lock-held (*flash-lock* ) + (let ((entry + (or (gethash key *flashes*) + (make-flash-entry)))) + ;; update the entry + (setf (flash-entry-timestamp entry) now + (getf (flash-entry-table entry) label) value + (gethash key *flashes*) entry))) ;; set the cookie, updating its expiration if necessary (lzb:set-response-cookie +flash-cookie-name+ key @@ -46,16 +51,20 @@ expires." "Retrieves and deletes the flashed value with label LABEL associated with this request. If the value exists, return it. Otherwise return NIL." - (a:when-let* ((key (lzb:request-cookie +flash-cookie-name+)) - (entry (gethash key *flashes*))) - (cond - ((flash-entry-alive-p entry) - (let ((val (getf (flash-entry-table entry) label))) - ;; can only retrieve once - (remf (flash-entry-table entry) label) - val)) - (t - ;; drop expired entries and return nil - (remhash key *flashes*) - nil)))) + (bt:with-lock-held (*flash-lock*) + (a:when-let* ((key (lzb:request-cookie +flash-cookie-name+)) + (entry (gethash key *flashes*))) + (cond + ((flash-entry-alive-p entry) + (let ((val (getf (flash-entry-table entry) label))) + ;; can only retrieve once + (remf (flash-entry-table entry) label) + ;; might as well delete the entry if its table is empty. + (when (null (flash-entry-table entry)) + (remhash key *flashes*)) + val)) + (t + ;; drop expired entries and return nil + (remhash key *flashes*) + nil))))) |