Compute dabbrev cands async

* helm-dabbrev.el (helm-dabbrev--get-candidates): Takes one more arg limit.
(helm-dabbrev--already-tried): New.
(helm-dabbrev--current-thread): New.
(helm-dabbrev): Compute candidates inside a thread if possible.

1 files changed, 42 insertions, 17 deletions

diff --git a/helm-dabbrev.el b/helm-dabbrev.el
index 92050ed6..956297bb 100644
--- a/helm-dabbrev.el
+++ b/helm-dabbrev.el
@@ -221,12 +221,12 @@ removed."
          sep-regexp ""
          (match-string-no-properties 99))))))
 
-(defun helm-dabbrev--get-candidates (abbrev)
+(defun helm-dabbrev--get-candidates (abbrev &optional limit)
   (cl-assert abbrev nil "[No Match]")
   (with-current-buffer (current-buffer)
     (let* ((dabbrev-get (lambda (str all-bufs)
                             (helm-dabbrev--collect
-                             str helm-dabbrev-candidates-number-limit
+                             str (or limit helm-dabbrev-candidates-number-limit)
                              (cl-case helm-dabbrev-case-fold-search
                                (smart (helm-set-case-fold-search-1 abbrev))
                                (t helm-dabbrev-case-fold-search))
@@ -250,6 +250,8 @@ removed."
        'helm-insert-completion-at-point
        beg end candidate))))
 
+(defvar helm-dabbrev--already-tried nil)
+(defvar helm-dabbrev--current-thread nil)
 ;;;###autoload
 (defun helm-dabbrev ()
   "Preconfigured helm for dynamic abbreviations."
@@ -272,18 +274,33 @@ removed."
            ;; in the meaning time.
            (not (eq last-command 'helm-dabbrev)))
       (setq helm-dabbrev--data nil))
+    ;; When candidates are requested in helm directly without cycling,
+    ;; we need them right now before running helm, so no need to use a
+    ;; thread here.
     (when cycling-disabled-p
       (setq helm-dabbrev--cache (helm-dabbrev--get-candidates dabbrev)))
+    ;; The idea here is to compute only the candidates needed to cycle
+    ;; and while cycling, compute the whole list in background with a
+    ;; thread so that user doesn't have to wait candidates are ready
+    ;; at startup.
     (unless (or cycling-disabled-p
                 (helm-dabbrev-info-p helm-dabbrev--data))
-      (setq helm-dabbrev--cache (helm-dabbrev--get-candidates dabbrev))
+      (if (fboundp 'make-thread)
+          (setq helm-dabbrev--current-thread
+                (make-thread
+                 (lambda ()
+                   (setq helm-dabbrev--cache
+                         (helm-dabbrev--get-candidates dabbrev)))))
+        (setq helm-dabbrev--cache
+                   (helm-dabbrev--get-candidates dabbrev)))
       (setq helm-dabbrev--data
             (make-helm-dabbrev-info
              :dabbrev dabbrev
              :limits limits
              :iterator
              (helm-iter-list
-              (cl-loop for i in helm-dabbrev--cache
+              (cl-loop for i in (helm-dabbrev--get-candidates
+                                 dabbrev helm-dabbrev-cycle-threshold)
                        when (and i (string-match
                                     (concat "^" (regexp-quote dabbrev)) i))
                        collect i into selection
@@ -308,8 +325,11 @@ removed."
              (car (helm-dabbrev-info-limits helm-dabbrev--data))
              (cdr limits) it)
             ;; Move already tried candidates to end of list.
-            (setq helm-dabbrev--cache (append (remove it helm-dabbrev--cache)
-                                              (list it))))
+            (push it helm-dabbrev--already-tried))
+        ;; Cycling is finished, ensure helm-dabbrev--cache have
+        ;; finished to complete before continuing by blocking thread.
+        (when (fboundp 'thread-join)
+          (thread-join helm-dabbrev--current-thread))
         ;; If the length of candidates is only one when computed
         ;; that's mean the unique matched item have already been
         ;; inserted by the iterator, so no need to reinsert the old dabbrev,
@@ -328,17 +348,22 @@ removed."
             (delete-region (car limits) (point))
             (insert dabbrev))
           (with-helm-show-completion (car limits) (cdr limits)
-            (helm :sources (helm-build-in-buffer-source "Dabbrev Expand"
-                             :data helm-dabbrev--cache
-                             :persistent-action 'ignore
-                             :persistent-help "DoNothing"
-                             :keymap helm-dabbrev-map
-                             :action 'helm-dabbrev-default-action
-                             :group 'helm-dabbrev)
-                  :buffer "*helm dabbrev*"
-                  :input (concat "^" dabbrev " ")
-                  :resume 'noresume
-                  :allow-nest t)))))))
+            (unwind-protect
+                 (helm :sources (helm-build-in-buffer-source "Dabbrev Expand"
+                                  :data (cl-loop for cand in helm-dabbrev--cache
+                                                 unless (member cand helm-dabbrev--already-tried)
+                                                 collect cand into lst
+                                                 finally return (append lst helm-dabbrev--already-tried))
+                                  :persistent-action 'ignore
+                                  :persistent-help "DoNothing"
+                                  :keymap helm-dabbrev-map
+                                  :action 'helm-dabbrev-default-action
+                                  :group 'helm-dabbrev)
+                       :buffer "*helm dabbrev*"
+                       :input (concat "^" dabbrev " ")
+                       :resume 'noresume
+                       :allow-nest t)
+              (setq helm-dabbrev--already-tried nil))))))))
 
 (provide 'helm-dabbrev)