Merge pull request #6 from vermiculus/precompiled-filters

Precompiled filters

5 files changed, 123 insertions, 31 deletions

diff --git a/.gitignore b/.gitignore
index 4acb5ef..2585bf5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,6 @@
 # Compiled Elisp
 *.elc
 /.cask/
+.dir-locals.el
+/.stackmode/
+/url/
diff --git a/stack-core.el b/stack-core.el
index 9a535cd..c2aff15 100644
--- a/stack-core.el
+++ b/stack-core.el
@@ -44,6 +44,10 @@
 
 ;;; Constants and Customizable Options
 
+(defcustom stack-cache-directory
+  (expand-file-name ".stackmode" user-emacs-directory)
+  "Directory containined cached files and precompiled filters.")
+
 (defconst stack-core-api-version
   "2.2"
   "The current version of the API.")
@@ -241,5 +245,33 @@ entire response as a complex alist."
 		     cons-cell))))
 	     data))))
 
+(defun stack-cache-get-file-name (filename)
+  "Expands FILENAME in the context of `stack-cache-directory'."
+  (expand-file-name filename stack-cache-directory))
+
+(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 1525a4b..4210549 100644
--- a/stack-filter.el
+++ b/stack-filter.el
@@ -32,9 +32,13 @@
 
 ;;; Customizations
 
+(defconst stack-filter-cache-file
+  "filters.el")
+
 (defvar stack-filter
   'default
-  "The current filter.  To customize the filter for the next call
+  "The current filter.
+To customize the filter for the next call
 to `stack-core-make-request', let-bind this variable to the
 output of a call to `stack-core-compile-filter'.  Be careful!  If
 you're going to be using this new filter a lot, create a variable
@@ -42,28 +46,58 @@ for it.  Creation requests count against
 `stack-core-remaining-api-requests'!")
 
 
-;;; Filter compilation
+;;; Compilation
 
+;;; TODO allow BASE to be a precompiled filter name
 (defun stack-filter-compile (&optional include exclude base)
-  "Compile a StackExchange filter including fields from INCLUDE,
-excluding those from EXCLUDE, using BASE as a base filter.
+  "Compile INCLUDE and EXCLUDE into a filter derived from BASE.
 
 INCLUDE and EXCLUDE must both be lists; BASE should be a symbol
 or string."
   (let ((keyword-arguments
-	 `((include . ,(if include (mapconcat
-				    #'stack-core-thing-as-string
-				    include ";")))
-	   (exclude . ,(if exclude (mapconcat
-				    #'stack-core-thing-as-string
-				    exclude ";")))
-	   (base    . ,(if base base)))))
+         `((include . ,(if include (mapconcat
+                                    #'stack-core-thing-as-string
+                                    include ";")))
+           (exclude . ,(if exclude (mapconcat
+                                    #'stack-core-thing-as-string
+                                    exclude ";")))
+           (base    . ,(if base base)))))
     (let ((response (stack-core-make-request
-		     "filter/create"
-		     keyword-arguments)))
+                     "filter/create"
+                     keyword-arguments)))
       (url-hexify-string
        (cdr (assoc 'filter
-		   (elt response 0)))))))
+                   (elt response 0)))))))
+
+
+;;; Storage and Retrieval
+
+(defun stack-filter-get (filter)
+  "Retrieve named FILTER from `stack-filter-cache-file'."
+  (cdr (assoc filter (stack-cache-get stack-filter-cache-file))))
+
+(defun stack-filter-store (name &optional filter)
+  "Store NAME as FILTER in `stack-filter-cache-file'.
+
+NAME should be a symbol and FILTER is a string as compiled by
+`stack-filter-compile'.
+
+If NAME is a cons cell, (car NAME) is taken to be the actual NAME
+and (cdr NAME) is taken to be the actual FILTER.  In this case,
+the second argument is simply ignored."
+  (let ((name   (if (consp name) (car name) name))
+        (filter (if (consp name) (cdr name) filter)))
+    (unless (symbolp name)
+      (error "Name must be a symbol: %S" name))
+    (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))))
+
+(defun stack-filter-store-all (name-filter-alist)
+  (mapc #'stack-filter-store name-filter-alist))
 
 (provide 'stack-filter)
 ;;; stack-filter.el ends here
diff --git a/stack-question.el b/stack-question.el
index 3902a39..eb5b8a3 100644
--- a/stack-question.el
+++ b/stack-question.el
@@ -28,9 +28,12 @@
 (require 'stack-filter)
 
 (defvar stack-question-browse-filter
-  (stack-filter-compile nil
+  (stack-filter-compile
+   nil
    '(user.profile_image shallow_user.profile_image)))
 
+(stack-filter-store 'question-browse stack-question-browse-filter)
+
 (defun stack-question-get-questions (site &optional page)
   "Get the page PAGE of questions from SITE."
   (stack-core-make-request
diff --git a/test/tests.el b/test/tests.el
index 44b0de0..e097244 100644
--- a/test/tests.el
+++ b/test/tests.el
@@ -5,25 +5,27 @@
      (if (string-prefix-p "stack-" (symbol-name symbol))
          (unintern symbol)))))
 
+;;; Tests
+
 (defun stack-test-sample-data (method &optional directory)
-  (with-current-buffer
-      (find-file-noselect
-       (concat "data-samples/"
-               (when directory (concat directory "/"))
-               method ".el"))
-    (eval (read (if (string-equal "" (buffer-string))
-                    "'no-value"
-                  (buffer-string))))))
+  (let ((file (concat "data-samples/"
+                      (when directory (concat directory "/"))
+                      method ".el")))
+    (when (file-exists-p file)
+      (with-temp-buffer
+        (insert-file-contents file)
+        (read (buffer-string))))))
 
-(setq stack-test-data-questions
-      (stack-test-sample-data "questions")
-      stack-test-data-sites
-      (stack-test-sample-data "sites"))
+(setq
+ stack-core-remaining-api-requests-message-threshold 50000
+ debug-on-error t
+ stack-core-silent-requests nil
+ user-emacs-directory "."
 
-;;; Tests
-
-(setq stack-core-remaining-api-requests-message-threshold 50000)
-(setq debug-on-error t)
+ stack-test-data-questions
+ (stack-test-sample-data "questions")
+ stack-test-data-sites
+ (stack-test-sample-data "sites"))
 
 (require 'stack-core)
 (require 'stack-question)
@@ -75,3 +77,21 @@
                              ((should-not-go))
                              ((1 . alpha) (2 . beta))]
                             '(1 2 3)))))
+
+(ert-deftest test-filters ()
+  (let ((stack-cache-directory (make-temp-file "stack-test" t)))
+    (should-error (stack-filter-store "names must be symbols"
+                                      "this is a filter"))
+    ;; basic use
+    (should (equal '((test . "filter"))
+                   (stack-filter-store 'test "filter")))
+    ;; aggregation
+    (should (equal '((test2 . "filter2") (test . "filter"))
+                   (stack-filter-store 'test2 "filter2")))
+    ;; mutation
+    (should (equal '((test2 . "filter2") (test . "filter-test"))
+                   (stack-filter-store 'test "filter-test")))
+    ;; clean up (note: the file should exist)
+    (delete-file
+     (stack-cache-get-file-name
+      stack-filter-cache-file))))