- (hash-table-count (oref db :data)))
-
-(defmethod registry-prune ((db registry-db))
- "Prunes the registry-db object THIS.
-Removes only entries without the :precious keys."
- (let* ((precious (oref db :precious))
- (precious-p (lambda (entry-key) (cdr (memq (car entry-key) precious))))
- (data (oref db :data))
- (limit (oref db :max-soft))
- (size (registry-size db))
- (candidates (loop for k being the hash-keys of data
- using (hash-values v)
- when (notany precious-p v)
- collect k))
- (candidates-count (length candidates))
- ;; are we over max-soft?
- (prune-needed (> size limit)))
-
- ;; while we have more candidates than we need to remove...
- (while (and (> candidates-count (- size limit)) candidates)
- (decf candidates-count)
- (setq candidates (cdr candidates)))
-
- (registry-delete db candidates nil)))
+ (hash-table-count (oref db :data)))
+
+ (defmethod registry-prune ((db registry-db) &optional sortfun)
+ "Prunes the registry-db object THIS.
+Removes only entries without the :precious keys if it can,
+then removes oldest entries first.
+Returns the number of deleted entries.
+If SORTFUN is given, tries to keep entries that sort *higher*.
+SORTFUN is passed only the two keys so it must look them up directly."
+ (dolist (collector '(registry-prune-soft-candidates
+ registry-prune-hard-candidates))
+ (let* ((size (registry-size db))
+ (collected (funcall collector db))
+ (limit (nth 0 collected))
+ (candidates (nth 1 collected))
+ ;; sort the candidates if SORTFUN was given
+ (candidates (if sortfun (sort candidates sortfun) candidates))
+ (candidates-count (length candidates))
+ ;; are we over max-soft?
+ (prune-needed (> size limit)))
+
+ ;; while we have more candidates than we need to remove...
+ (while (and (> candidates-count (- size limit)) candidates)
+ (decf candidates-count)
+ (setq candidates (cdr candidates)))
+
+ (registry-delete db candidates nil)
+ (length candidates))))
+
+ (defmethod registry-prune-soft-candidates ((db registry-db))
+ "Collects pruning candidates from the registry-db object THIS.
+Proposes only entries without the :precious keys."
+ (let* ((precious (oref db :precious))
+ (precious-p (lambda (entry-key)
+ (cdr (memq (car entry-key) precious))))
+ (data (oref db :data))
+ (limit (oref db :max-soft))
+ (candidates (loop for k being the hash-keys of data
+ using (hash-values v)
+ when (notany precious-p v)
+ collect k)))
+ (list limit candidates)))
+
+ (defmethod registry-prune-hard-candidates ((db registry-db))
+ "Collects pruning candidates from the registry-db object THIS.
+Proposes any entries over the max-hard limit minus size * prune-factor."
+ (let* ((data (oref db :data))
+ ;; prune to (size * prune-factor) below the max-hard limit so
+ ;; we're not pruning all the time
+ (limit (max 0 (- (oref db :max-hard)
+ (* (registry-size db) (oref db :prune-factor)))))
+ (candidates (loop for k being the hash-keys of data
+ collect k)))
+ (list limit candidates))))