From: Austin Clements <amdragon@MIT.EDU> This was a little hack to test the feasibility of switching notmuch-tag-formats to use regexps with caching for performance. In the end it works fine and isn't particularly complex, though there were a few gotchas: 1) We have to clear the cache somehow on changes to notmuch-tag-formats. I opted to use a defcustom :set plus some documentation telling people what to do if they change it directly from Elisp. This is less automatic than I would like, but I doubt people are changing this very often and I concluded that any machinery to automatically detect changes to notmuch-tag-formats would probably outweigh the benefits of caching. Alternatively, we could require search/show/tree buffers to "opt in" to caching when they start building. 2) I spent way too long trying to use assoc-default before realizing this it just wouldn't work, since there's no way to distinguish a missing key from a present key with a null cdr. assoc* from cl works fine. Performance-wise, the caching of regexp lookup makes this just as fast as assoc for unformatted tags (it would probably be faster if someone had a really big `notmuch-tag-formats') and the caching of eval results makes this much *faster* than the current code for formatted tags. inbox (usec) unread (usec) assoc: 0.4 2.8 regexp: 3.2 7.2 regexp+caching: 0.4 0.4 That said, even at 7.2 usec, tag formatting is still *very* fast (though regexp matching may get noticeably slower with larger `notmuch-tag-formats'). Tag formatting is nowhere near our top bottleneck. --- emacs/notmuch-tag.el | 75 +++++++++++++++++++++++++++++++++++-------------- 1 files changed, 53 insertions(+), 22 deletions(-) diff --git a/emacs/notmuch-tag.el b/emacs/notmuch-tag.el index 908e7ad..cb88fd5 100644 --- a/emacs/notmuch-tag.el +++ b/emacs/notmuch-tag.el @@ -28,35 +28,56 @@ (require 'crm) (require 'notmuch-lib) +;; (notmuch-tag-clear-cache will be called by the defcustom +;; notmuch-tag-formats, so it has to be defined first.) + +(defvar notmuch-tag--format-cache (make-hash-table :test 'equal) + "Cache of tag format lookup. Internal to `notmuch-tag-format-tag'.") + +(defun notmuch-tag-clear-cache () + "Clear the internal cache of tag formats. + +This must be called after changes to `notmuch-tag-formats'." + (clrhash notmuch-tag--format-cache)) + (defcustom notmuch-tag-formats '(("unread" (propertize tag 'face '(:foreground "red"))) ("flagged" (propertize tag 'face '(:foreground "blue")) (notmuch-tag-format-image-data tag (notmuch-tag-star-icon)))) "Custom formats for individual tags. -This gives a list that maps from tag names to lists of formatting -expressions. The car of each element gives a tag name and the -cdr gives a list of Elisp expressions that modify the tag. If -the list is empty, the tag will simply be hidden. Otherwise, -each expression will be evaluated in order: for the first -expression, the variable `tag' will be bound to the tag name; for -each later expression, the variable `tag' will be bound to the -result of the previous expression. In this way, each expression -can build on the formatting performed by the previous expression. -The result of the last expression will displayed in place of the -tag. +This is an association list that maps from tag name regexps to +lists of formatting expressions. The first entry whose car +regexp-matches a tag will be used to format that tag. The regexp +is implicitly anchored, so to match a literal tag name, just use +that tag name (if it contains special regexp characters like +\".\" or \"*\", these have to be escaped). The cdr of the +matching entry gives a list of Elisp expressions that modify the +tag. If the list is empty, the tag will simply be hidden. +Otherwise, each expression will be evaluated in order: for the +first expression, the variable `tag' will be bound to the tag +name; for each later expression, the variable `tag' will be bound +to the result of the previous expression. In this way, each +expression can build on the formatting performed by the previous +expression. The result of the last expression will displayed in +place of the tag. For example, to replace a tag with another string, simply use that string as a formatting expression. To change the foreground of a tag to red, use the expression (propertize tag 'face '(:foreground \"red\")) +After modifying this variable in Elisp, be sure to call +`notmuch-tag-clear-cache'. Modifying this via customize does +this automatically. + See also `notmuch-tag-format-image', which can help replace tags with images." :group 'notmuch-search :group 'notmuch-show - :type '(alist :key-type (string :tag "Tag") + :set (lambda (var val) (set-default var val) (notmuch-tag-clear-cache)) + :type '(alist :key-type (regexp :tag "Tag") :extra-offset -3 :value-type (radio :format "%v" @@ -137,16 +158,26 @@ This can be used with `notmuch-tag-format-image-data'." (defun notmuch-tag-format-tag (tag) "Format TAG by looking into `notmuch-tag-formats'." - (let ((formats (assoc tag notmuch-tag-formats))) - (cond - ((null formats) ;; - Tag not in `notmuch-tag-formats', - tag) ;; the format is the tag itself. - ((null (cdr formats)) ;; - Tag was deliberately hidden, - nil) ;; no format must be returned - (t ;; - Tag was found and has formats, - (let ((tag tag)) ;; we must apply all the formats. - (dolist (format (cdr formats) tag) - (setq tag (eval format)))))))) + (let ((formatted (gethash tag notmuch-tag--format-cache 'missing))) + (when (eq formatted 'missing) + (let* ((formats + (save-match-data + (assoc* tag notmuch-tag-formats + :test (lambda (tag key) + (and (eq (string-match key tag) 0) + (= (match-end 0) (length tag)))))))) + (setq formatted + (cond + ((null formats) ;; - Tag not in `notmuch-tag-formats', + tag) ;; the format is the tag itself. + ((null (cdr formats)) ;; - Tag was deliberately hidden, + nil) ;; no format must be returned + (t ;; - Tag was found and has formats, + (let ((tag tag)) ;; we must apply all the formats. + (dolist (format (cdr formats) tag) + (setq tag (eval format))))))) + (puthash tag formatted notmuch-tag--format-cache))) + formatted)) (defun notmuch-tag-format-tags (tags &optional face) "Return a string representing formatted TAGS." -- 1.7.9.1