lisp/find-lisp.el

   1 ;;; find-lisp.el --- emulation of find in Emacs Lisp  -*- lexical-binding: t -*-
   2
   3 ;; Author: Peter Breton
   4 ;; Created: Fri Mar 26 1999
   5 ;; Keywords: unix
   6
   7 ;; Copyright (C) 1999-2018 Free Software Foundation, Inc.
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25 ;;
  26 ;; This is a very generalized form of find; it basically implements a
  27 ;; recursive directory descent. The conditions which bound the search
  28 ;; are expressed as predicates, and I have not addressed the question
  29 ;; of how to wrap up the common chores that find does in a simpler
  30 ;; format than writing code for all the various predicates.
  31 ;;
  32 ;; Some random thoughts are to express simple queries directly with
  33 ;; user-level functions, and perhaps use some kind of forms interface
  34 ;; for medium-level queries. Really complicated queries can be
  35 ;; expressed in Lisp.
  36 ;;
  37
  38 ;;; Todo
  39 ;;
  40 ;; It would be nice if we could sort the results without running the find
  41 ;; again. Maybe that could work by storing the original file attributes?
  42
  43 ;;; Code:
  44
  45 (require 'dired)
  46
  47 (defvar dired-buffers)
  48 (defvar dired-subdir-alist)
  49
  50 ;; Internal variables
  51
  52 (defvar find-lisp-regexp nil
  53   "Internal variable.")
  54
  55 (defconst find-lisp-line-indent "  "
  56   "Indentation for Dired file lines.")
  57
  58 (defvar find-lisp-file-predicate nil
  59   "Predicate for choosing to include files.")
  60
  61 (defvar find-lisp-directory-predicate nil
  62   "Predicate for choosing to descend into directories.")
  63
  64 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  65 ;; Debugging Code
  66 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  67
  68 (defvar find-lisp-debug-buffer "*Find Lisp Debug*"
  69   "Buffer for debugging information.")
  70
  71 (defvar find-lisp-debug nil
  72   "Whether debugging is enabled.")
  73
  74 (defun find-lisp-debug-message (message)
  75   "Print a debug message MESSAGE in `find-lisp-debug-buffer'."
  76   (set-buffer (get-buffer-create find-lisp-debug-buffer))
  77   (goto-char (point-max))
  78   (insert message "\n"))
  79
  80 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  81 ;; Directory and File predicates
  82 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  83
  84 (defun find-lisp-default-directory-predicate  (dir parent)
  85   "True if DIR is not a dot file, and not a symlink.
  86 PARENT is the parent directory of DIR."
  87   (and find-lisp-debug
  88        (find-lisp-debug-message
  89         (format "Processing directory %s in %s" dir parent)))
  90   ;; Skip current and parent directories
  91   (not (or (string= dir ".")
  92            (string= dir "..")
  93            ;; Skip directories which are symlinks
  94            ;; Easy way to circumvent recursive loops
  95            (file-symlink-p (expand-file-name dir parent)))))
  96
  97 (defun find-lisp-default-file-predicate  (file dir)
  98   "True if FILE matches `find-lisp-regexp'.
  99 DIR is the directory containing FILE."
 100   (and find-lisp-debug
 101        (find-lisp-debug-message
 102         (format "Processing file %s in %s" file dir)))
 103   (and (not (file-directory-p (expand-file-name file dir)))
 104        (string-match find-lisp-regexp file)))
 105
 106 (defun find-lisp-file-predicate-is-directory  (file dir)
 107   "True if FILE is a directory.
 108 Argument DIR is the directory containing FILE."
 109   (and find-lisp-debug
 110        (find-lisp-debug-message
 111         (format "Processing file %s in %s" file dir)))
 112   (and (file-directory-p (expand-file-name file dir))
 113        (not (or (string= file ".")
 114                 (string= file "..")))))
 115
 116 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 117 ;; Find functions
 118 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 119
 120 (defun find-lisp-find-files (directory regexp)
 121   "Find files under DIRECTORY, recursively, that match REGEXP."
 122   (let ((file-predicate      'find-lisp-default-file-predicate)
 123         (directory-predicate 'find-lisp-default-directory-predicate)
 124         (find-lisp-regexp regexp))
 125     (find-lisp-find-files-internal
 126      directory
 127      file-predicate
 128      directory-predicate)))
 129
 130 ;; Workhorse function
 131 (defun find-lisp-find-files-internal (directory file-predicate
 132                                                 directory-predicate)
 133   "Find files under DIRECTORY which satisfy FILE-PREDICATE.
 134 FILE-PREDICATE is a function which takes two arguments: the file and its
 135 directory.
 136
 137 DIRECTORY-PREDICATE is used to decide whether to descend into directories.
 138 It is a function which takes two arguments, the directory and its parent."
 139   (setq directory (file-name-as-directory directory))
 140   (let (results sub-results)
 141     (dolist (file (directory-files directory nil nil t))
 142       (let ((fullname (expand-file-name file directory)))
 143         (when (file-readable-p (expand-file-name file directory))
 144           ;; If a directory, check it we should descend into it
 145           (and (file-directory-p fullname)
 146                (funcall directory-predicate file directory)
 147                (progn
 148                  (setq sub-results
 149                        (find-lisp-find-files-internal
 150                         fullname
 151                         file-predicate
 152                         directory-predicate))
 153                  (if results
 154                      (nconc results sub-results)
 155                    (setq results sub-results))))
 156           ;; For all files and directories, call the file predicate
 157           (and (funcall file-predicate file directory)
 158                (if results
 159                    (nconc results (list fullname))
 160                  (setq results (list fullname)))))))
 161     results))
 162
 163 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 164 ;; Find-dired all in Lisp
 165 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 166
 167 ;;;###autoload
 168 (defun find-lisp-find-dired (dir regexp)
 169   "Find files in DIR, matching REGEXP."
 170   (interactive "DFind files in directory: \nsMatching regexp: ")
 171   (let ((find-lisp-regexp regexp))
 172     (find-lisp-find-dired-internal
 173      dir
 174      'find-lisp-default-file-predicate
 175      'find-lisp-default-directory-predicate
 176      "*Find Lisp Dired*")))
 177
 178 ;; Just the subdirectories
 179 ;;;###autoload
 180 (defun find-lisp-find-dired-subdirectories (dir)
 181   "Find all subdirectories of DIR."
 182   (interactive "DFind subdirectories of directory: ")
 183   (find-lisp-find-dired-internal
 184    dir
 185    'find-lisp-file-predicate-is-directory
 186    'find-lisp-default-directory-predicate
 187    "*Find Lisp Dired Subdirectories*"))
 188
 189 ;; Most of this is lifted from find-dired.el
 190 ;;
 191 (defun find-lisp-find-dired-internal (dir file-predicate
 192                                           directory-predicate buffer-name)
 193   "Run find (Lisp version) and go into Dired mode on a buffer of the output."
 194   (let ((dired-buffers dired-buffers)
 195         (regexp find-lisp-regexp))
 196     ;; Expand DIR ("" means default-directory), and make sure it has a
 197     ;; trailing slash.
 198     (setq dir (file-name-as-directory (expand-file-name dir)))
 199     ;; Check that it's really a directory.
 200     (or (file-directory-p dir)
 201         (error "find-dired needs a directory: %s" dir))
 202     (or
 203      (and (buffer-name)
 204           (string= buffer-name (buffer-name)))
 205         (switch-to-buffer (get-buffer-create buffer-name)))
 206     (widen)
 207     (kill-all-local-variables)
 208     (setq buffer-read-only nil)
 209     (erase-buffer)
 210     (setq default-directory dir)
 211     (dired-mode dir)
 212
 213     (use-local-map (append (make-sparse-keymap) (current-local-map)))
 214
 215     (make-local-variable 'find-lisp-file-predicate)
 216     (setq find-lisp-file-predicate file-predicate)
 217     (make-local-variable 'find-lisp-directory-predicate)
 218     (setq find-lisp-directory-predicate directory-predicate)
 219     (make-local-variable 'find-lisp-regexp)
 220     (setq find-lisp-regexp regexp)
 221
 222     (make-local-variable 'revert-buffer-function)
 223     (setq revert-buffer-function
 224           (function
 225            (lambda (_ignore1 _ignore2)
 226              (find-lisp-insert-directory
 227               default-directory
 228               find-lisp-file-predicate
 229               find-lisp-directory-predicate
 230               'ignore)
 231              )
 232            ))
 233
 234     ;; Set subdir-alist so that Tree Dired will work:
 235     (if (fboundp 'dired-simple-subdir-alist)
 236         ;; will work even with nested dired format (dired-nstd.el,v 1.15
 237         ;; and later)
 238         (dired-simple-subdir-alist)
 239       ;; else we have an ancient tree dired (or classic dired, where
 240       ;; this does no harm)
 241       (set (make-local-variable 'dired-subdir-alist)
 242            (list (cons default-directory (point-min-marker)))))
 243     (find-lisp-insert-directory
 244      dir file-predicate directory-predicate 'ignore)
 245     (goto-char (point-min))
 246     (dired-goto-next-file)))
 247
 248 (defun find-lisp-insert-directory (dir
 249                                    file-predicate
 250                                    directory-predicate
 251                                    _sort-function)
 252   "Insert the results of `find-lisp-find-files' in the current buffer."
 253   (let ((buffer-read-only nil)
 254         (files (find-lisp-find-files-internal
 255                 dir
 256                 file-predicate
 257                 directory-predicate))
 258         (len (length dir)))
 259     (erase-buffer)
 260     ;; Subdir headlerline must come first because the first marker in
 261     ;; subdir-alist points there.
 262     (insert find-lisp-line-indent dir ":\n")
 263     ;; Make second line a ``find'' line in analogy to the ``total'' or
 264     ;; ``wildcard'' line.
 265     ;;
 266     ;; No analog for find-lisp?
 267     (insert find-lisp-line-indent "\n")
 268     ;; Run the find function
 269     (mapc
 270      (function
 271       (lambda (file)
 272         (find-lisp-find-dired-insert-file
 273          (substring file len)
 274          (current-buffer))))
 275      (sort files 'string-lessp))
 276     ;; FIXME: Sort function is ignored for now
 277     ;; (funcall sort-function files))
 278     (goto-char (point-min))
 279     (dired-goto-next-file)))
 280
 281 ;;;###autoload
 282 (defun find-lisp-find-dired-filter (regexp)
 283   "Change the filter on a `find-lisp-find-dired' buffer to REGEXP."
 284   (interactive "sSet filter to regexp: ")
 285   (setq find-lisp-regexp regexp)
 286   (revert-buffer))
 287
 288 (defun find-lisp-find-dired-insert-file (file buffer)
 289   (set-buffer buffer)
 290   (insert find-lisp-line-indent
 291           (find-lisp-format file (file-attributes file 'string) (list "")
 292                           (current-time))))
 293
 294 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 295 ;; Lifted from ls-lisp. We don't want to require it, because that
 296 ;; would alter the insert-directory function.
 297 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 298
 299 (defun find-lisp-format (file-name file-attr switches now)
 300   "Format one line of long ls output for file FILE-NAME.
 301 FILE-ATTR and FILE-SIZE give the file's attributes and size.
 302 SWITCHES and TIME-INDEX give the full switch list and time data."
 303   (let ((file-type (nth 0 file-attr)))
 304     (concat (if (memq ?i switches)      ; inode number
 305                 (format "%6d " (nth 10 file-attr)))
 306             ;; nil is treated like "" in concat
 307             (if (memq ?s switches)      ; size in K
 308                 (format "%4d " (1+ (/ (nth 7 file-attr) 1024))))
 309             (nth 8 file-attr)           ; permission bits
 310             (format " %3d %-8s %-8s %8d "
 311                     (nth 1 file-attr)   ; no. of links
 312                     (if (numberp (nth 2 file-attr))
 313                         (int-to-string (nth 2 file-attr))
 314                       (nth 2 file-attr)) ; uid
 315                     (if (eq system-type 'ms-dos)
 316                         "root"          ; everything is root on MSDOS.
 317                       (if (numberp (nth 3 file-attr))
 318                           (int-to-string (nth 3 file-attr))
 319                         (nth 3 file-attr))) ; gid
 320                     (nth 7 file-attr)   ; size in bytes
 321                     )
 322             (find-lisp-format-time file-attr switches now)
 323             " "
 324             file-name
 325             (if (stringp file-type)     ; is a symbolic link
 326                 (concat " -> " file-type)
 327               "")
 328             "\n")))
 329
 330 (defun find-lisp-time-index (switches)
 331   "Return index into file-attributes according to ls SWITCHES."
 332   (cond
 333    ((memq ?c switches) 6)               ; last mode change
 334    ((memq ?u switches) 4)               ; last access
 335    ;; default is last modtime
 336    (t 5)))
 337
 338 (defun find-lisp-format-time (file-attr switches now)
 339   "Format time string for file.
 340 This is done with attributes FILE-ATTR according to SWITCHES (a
 341 list of ls option letters of which c and u are recognized).  Use
 342 the same method as \"ls\" to decide whether to show time-of-day or
 343 year, depending on distance between file date and NOW."
 344   (let* ((time (nth (find-lisp-time-index switches) file-attr))
 345          (diff16 (- (car time) (car now)))
 346          (diff (+ (ash diff16 16) (- (car (cdr time)) (car (cdr now)))))
 347          (past-cutoff (- (* 6 30 24 60 60)))    ; 6 30-day months
 348          (future-cutoff (* 60 60)))             ; 1 hour
 349     (format-time-string
 350      (if (and
 351           (<= past-cutoff diff) (<= diff future-cutoff)
 352           ;; Sanity check in case `diff' computation overflowed.
 353           (<= (1- (ash past-cutoff -16)) diff16)
 354           (<= diff16 (1+ (ash future-cutoff -16))))
 355          "%b %e %H:%M"
 356        "%b %e  %Y")
 357      time)))
 358
 359 (provide 'find-lisp)
 360
 361 ;;; find-lisp.el ends here