ivy.el (ivy--filter): allow filter to be interruptible with input.

ivy.el

@@ -3318,7 +3318,7 @@ Should be run via minibuffer `post-command-hook'."
                  (setq ivy--old-re nil))))
         (with-current-buffer (ivy-state-buffer ivy-last)
           (ivy--format
-           (ivy--filter ivy-text ivy--all-candidates))))
+           (ivy--filter ivy-text ivy--all-candidates 'interruptible))))
     (setq ivy--old-text ivy-text)))
 
 (defun ivy-display-function-fallback (str)
@@ -3448,7 +3448,20 @@ In any Ivy completion session, the case folding starts with
   ;; Reset cache so that the candidate list updates.
   (setq ivy--old-re nil))
 
-(defun ivy--re-filter (re candidates &optional mkpred)
+(defmacro ivy--while-no-input (&rest body)
+  "Wrap BODY in `while-no-input'.
+Return the value if success running BODY."
+  (declare (debug t) (indent 0))
+  `(let ((ret (while-no-input ,@body)))
+     (unless (booleanp ret) ret)))
+
+(defun ivy--re-filter (re candidates &optional mkpred interruptible)
+  "Like `ivy--re-filter-1' but interruptible by keyboard."
+  (if interruptible
+      (ivy--while-no-input (ivy--re-filter-1 re candidates mkpred))
+    (ivy--re-filter-1 re candidates mkpred)))
+
+(defun ivy--re-filter-1 (re candidates &optional mkpred)
   "Return all RE matching CANDIDATES.
 RE is a list of cons cells, with a regexp car and a boolean cdr.
 When the cdr is t, the car must match.
@@ -3468,9 +3481,10 @@ Otherwise, the car must not match."
                            pred))))
       candidates)))
 
-(defun ivy--filter (name candidates)
+(defun ivy--filter (name candidates &optional interruptible)
   "Return all items that match NAME in CANDIDATES.
-CANDIDATES are assumed to be static."
+CANDIDATES are assumed to be static.
+When INTERRUPTIBLE, keyboard input can stop filtering."
   (let ((re (funcall ivy--regex-function name)))
     (if (and
          ivy--old-re
@@ -3496,20 +3510,20 @@ CANDIDATES are assumed to be static."
                                    re)
                                   '(0 2))
                             ivy--old-cands
-                            (ivy--re-filter re ivy--old-cands)))
+                            (ivy--re-filter re ivy--old-cands nil interruptible)))
                       (t
-                       (ivy--re-filter re candidates)))))
+                       (ivy--re-filter re candidates nil interruptible)))))
         (if (memq (cdr (assq (ivy-state-caller ivy-last)
                              ivy-index-functions-alist))
                   '(ivy-recompute-index-swiper
                     ivy-recompute-index-swiper-async
                     ivy-recompute-index-swiper-async-backward
                     ivy-recompute-index-swiper-backward))
             (progn
-              (ivy--recompute-index re-str cands)
+              (ivy--recompute-index re-str cands interruptible)
               (setq ivy--old-cands (ivy--sort name cands)))
           (setq ivy--old-cands (ivy--sort name cands))
-          (ivy--recompute-index re-str ivy--old-cands))
+          (ivy--recompute-index re-str ivy--old-cands interruptible))
         (setq ivy--old-re re)
         ivy--old-cands))))
 
@@ -3653,7 +3667,14 @@ no sorting is done.")
 (defvar ivy--recompute-index-inhibit nil
   "When non-nil, `ivy--recompute-index' is a no-op.")
 
-(defun ivy--recompute-index (re-str cands)
+
+(defun ivy--recompute-index (re-str cands &optional interruptible)
+  "Like `ivy--recompute-index-1' but interruptible by keyboard."
+  (if interruptible
+      (ivy--while-no-input (ivy--recompute-index-1 re-str cands))
+    (ivy--recompute-index-1 re-str cands)))
+
+(defun ivy--recompute-index-1 (re-str cands)
   "Recompute index of selected candidate matching RE-STR.
 CANDS are the current candidates."
   (let ((caller (ivy-state-caller ivy-last))