cp-find-file, cp: New custom variable cp-find-file-more-chars

Fixes #151

README.md

@@ -319,7 +319,9 @@ If you want some initial input to be inserted in the minibuffer every time you c
 ## Matcher for `counsel-projectile-find-file`
 By default, the command `counsel-projectile-find-file` relies on the the matcher of the command `counsel-find-file` to display files matching minibuffer input, allowing to ignore some files based on the variable `counsel-find-file-ignore-regexp`. It is possible to use another matcher by setting the variable `counsel-projectile-find-file-matcher`. Some choices are proposed if you use the Customize interface, in particular the `counsel-projectile-find-file-matcher-basename` matcher which is provided by counsel-projectile and only displays files whose basename matches the minibuffer input (if there is none, it shows all matching files).
 
-The matcher specified by `counsel-find-file-ignore-regexp` is also used by `counsel-projectile` to match files.
+Independently of the chosen matcher, it is possible to specifying a minimum number of characters to input before the matching project files are shown through the variable `counsel-projectile-find-file-more-chars`.  The default value is `0`, but a strictly positive value can improve performance in large projects.
+
+The values of `counsel-projectile-find-file-matcher` and `counsel-projectile-find-file-more-chars` are also used by `counsel-projectile` to match files.
 ## Sorting candidates
 The following commands allow to modify the way candidates are sorted:
 - `cousnel-projectile-switch-project`

counsel-projectile.el

@@ -283,6 +283,13 @@ It is also possible to use a custom matcher.  It must be a function taking two a
           (function :tag "Custom function"))
   :group 'counsel-projectile)
 
+(defcustom counsel-projectile-find-file-more-chars 0
+  "Number of characters to input before matching project files are shown.
+
+Setting it to a strictly positive value can improve performance in large projects."
+  :type 'integer
+  :group 'counsel-projectile)
+
 (counsel-projectile--defcustom-action
  'counsel-projectile-find-file
  '(1
@@ -302,6 +309,12 @@ It is also possible to use a custom matcher.  It must be a function taking two a
     "switch project"))
  'counsel-projectile)
 
+(defun counsel-projectile--find-file-matcher (regexp candidates)
+  (let ((ivy-more-chars-alist
+         `((t . ,counsel-projectile-find-file-more-chars))))
+    (or (ivy-more-chars)
+        (funcall counsel-projectile-find-file-matcher regexp candidates))))
+
 (defun counsel-projectile-find-file-matcher-basename (regexp candidates)
   "Return the list of CANDIDATES whose basename matches REGEXP,
 or if there is none the list of all CANDIDATES matching REGEXP.
@@ -393,7 +406,7 @@ non-nil, use completion based on context."
            (files (and dwim (projectile-select-files project-files))))
       (ivy-read (projectile-prepend-project-name "Find file: ")
                 (or files project-files)
-                :matcher counsel-projectile-find-file-matcher
+                :matcher #'counsel-projectile--find-file-matcher
                 :require-match t
                 :sort counsel-projectile-sort-files
                 :action counsel-projectile-find-file-action
@@ -1476,7 +1489,7 @@ Relies on `ivy--switch-buffer-matcher' for buffers and the
 matcher specified in `counsel-projectile-find-file-matcher' for
 files."
   (append (ivy--switch-buffer-matcher regexp counsel-projectile--buffers)
-          (funcall counsel-projectile-find-file-matcher regexp counsel-projectile--non-visited-files)))
+          (counsel-projectile--find-file-matcher regexp counsel-projectile--non-visited-files)))
 
 (defun counsel-projectile-action (name)
   "Switch to buffer or find file named NAME."