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Diffstat (limited to 'modules/cj-cache.el')
| -rw-r--r-- | modules/cj-cache.el | 95 |
1 files changed, 0 insertions, 95 deletions
diff --git a/modules/cj-cache.el b/modules/cj-cache.el deleted file mode 100644 index b7d048c9..00000000 --- a/modules/cj-cache.el +++ /dev/null @@ -1,95 +0,0 @@ -;;; cj-cache.el --- Generic TTL cache with build-guard -*- lexical-binding: t; -*- - -;; Author: Craig Jennings <c@cjennings.net> - -;;; Commentary: - -;; Generic "rebuild a long-running computation behind a TTL" cache, -;; with a building-flag guard that prevents duplicate concurrent -;; rebuilds in async-build scenarios. -;; -;; Used by org-agenda-config and org-refile-config which previously -;; carried parallel hand-rolled implementations of this exact shape. -;; See docs/design/cache-helper-design.org for the API contract, -;; consumer migration shape, and rationale for the deliberate "nil -;; cached value reads as invalid" decision. -;; -;; Out of scope: buffer-local key-based caches like the modeline VC -;; cache (different lifecycle). - -;;; Code: - -(require 'cl-lib) - -(defun cj/cache-make (&rest plist) - "Return a fresh cache state. -PLIST keywords: -- =:ttl= seconds to retain a built value (default 3600)." - (let ((ttl (or (plist-get plist :ttl) 3600))) - (list :value nil :time nil :ttl ttl :building nil))) - -(defun cj/cache-valid-p (cache) - "Return non-nil when CACHE has a fresh, non-nil value within its TTL. -A nil cached value reads as invalid by design -- a build that legitimately -returns nil rebuilds on the next request, matching the prior agenda/refile -contract." - (let ((value (plist-get cache :value)) - (time (plist-get cache :time)) - (ttl (plist-get cache :ttl))) - (and value - time - (< (- (float-time) time) ttl)))) - -(defun cj/cache-building-p (cache) - "Return non-nil when a build is currently in progress on CACHE." - (plist-get cache :building)) - -(defun cj/cache-invalidate (cache) - "Clear CACHE's value and timestamp. TTL is preserved." - (plist-put cache :value nil) - (plist-put cache :time nil)) - -(cl-defun cj/cache-value-or-rebuild (cache build-fn - &key force-rebuild - on-hit - on-build-start - on-build-success - on-build-error) - "Return CACHE's value, calling BUILD-FN to rebuild when invalid. - -When CACHE is valid and FORCE-REBUILD is nil, return the stored value -and call ON-HIT (if given) with the value. Otherwise call BUILD-FN, -store its result, and return it. - -The four callbacks let the consumer log without this helper printing on -its behalf: -- ON-HIT (value) -- ON-BUILD-START () -- ON-BUILD-SUCCESS (value) -- ON-BUILD-ERROR (err) - -The :building flag is set before BUILD-FN runs and cleared inside an -`unwind-protect' regardless of outcome. Errors from BUILD-FN are -rethrown after ON-BUILD-ERROR fires." - (cond - ((and (not force-rebuild) (cj/cache-valid-p cache)) - (let ((value (plist-get cache :value))) - (when on-hit (funcall on-hit value)) - value)) - (t - (when on-build-start (funcall on-build-start)) - (plist-put cache :building t) - (unwind-protect - (condition-case err - (let ((value (funcall build-fn))) - (plist-put cache :value value) - (plist-put cache :time (float-time)) - (when on-build-success (funcall on-build-success value)) - value) - (error - (when on-build-error (funcall on-build-error err)) - (signal (car err) (cdr err)))) - (plist-put cache :building nil))))) - -(provide 'cj-cache) -;;; cj-cache.el ends here |
