Implement and use `stack-cache-get' and `-set'

2 files changed, 32 insertions, 22 deletions

diff --git a/stack-core.el b/stack-core.el
index f9b9669..c2aff15 100644
--- a/stack-core.el
+++ b/stack-core.el
@@ -249,13 +249,29 @@ entire response as a complex alist."
   "Expands FILENAME in the context of `stack-cache-directory'."
   (expand-file-name filename stack-cache-directory))
 
-(defun stack-cache-get-file (filename)
-  "Return a buffer for FILENAME from `stack-cache-directory'."
-  (let ((find-file-hook nil)
-        (file (stack-cache-get-file-name filename)))
-    (unless (file-exists-p stack-cache-directory)
-      (mkdir stack-cache-directory))
-    (find-file-noselect file)))
+(defun stack-cache-get (cache)
+  "Return the data within CACHE.
+
+As with `stack-cache-set', CACHE is a file name within the
+context of `stack-cache-directory'."
+  (unless (file-exists-p stack-cache-directory)
+    (mkdir stack-cache-directory))
+  (let ((file (stack-cache-get-file-name cache)))
+    (when (file-exists-p file)
+      (with-temp-buffer
+        (insert-file-contents (stack-cache-get-file-name cache))
+        (read (buffer-string))))))
+
+(defun stack-cache-set (cache data)
+  "Set the content of CACHE to DATA.
+
+As with `stack-cache-get', CACHE is a file name within the
+context of `stack-cache-directory'."
+  (unless (file-exists-p stack-cache-directory)
+    (mkdir stack-cache-directory))
+  (write-region (prin1-to-string data) nil
+                (stack-cache-get-file-name cache))
+  data)
 
 (provide 'stack-core)
 ;;; stack-core.el ends here
diff --git a/stack-filter.el b/stack-filter.el
index e5fb54d..91c4875 100644
--- a/stack-filter.el
+++ b/stack-filter.el
@@ -74,9 +74,7 @@ or string."
 
 (defun stack-filter-get (filter)
   "Retrieve named FILTER from `stack-filter-cache-file'."
-  (with-current-buffer (stack-cache-get-file stack-filter-cache-file)
-    (or (cdr (ignore-errors (assoc filter (read (buffer-string)))))
-        nil)))
+  (cdr (assoc filter (stack-cache-get stack-filter-cache-file))))
 
 (defun stack-filter-store (name filter)
   "Store NAME as FILTER in `stack-filter-cache-file'.
@@ -85,17 +83,12 @@ NAME should be a symbol and FILTER is a string as compiled by
 `stack-filter-compile'."
   (unless (symbolp name)
     (error "Name must be a symbol: %S" name))
-  (with-current-buffer (stack-cache-get-file stack-filter-cache-file)
-    (let* ((dict (or (ignore-errors
-                       (read (buffer-string)))
-                     nil))
-           (entry (assoc name dict)))
-      (if entry (setf (cdr entry) filter)
-        (setq dict (cons (cons name filter) dict)))
-      (erase-buffer)
-      (insert (prin1-to-string dict))
-      (save-buffer)
-      dict)))
+  (let* ((dict (stack-cache-get stack-filter-cache-file))
+         (entry (assoc name dict)))
+    (if entry (setcdr entry filter)
+      (setq dict (cons (cons name filter) dict)))
+
+    (stack-cache-set stack-filter-cache-file dict)))
 
 ;;; TODO tail recursion should be made more efficient for the
 ;;; byte-compiler
@@ -104,7 +97,8 @@ NAME should be a symbol and FILTER is a string as compiled by
     (stack-filter-store
      (caar name-filter-alist)
      (cdar name-filter-alist))
-    (stack-filter-store-all (cdr name-filter-alist))))
+    (stack-filter-store-all
+     (cdr name-filter-alist))))
 
 (provide 'stack-filter)
 ;;; stack-filter.el ends here