emacs-lisp/package.el (package--get-deps): Fix returning duplicates.
[emacs.git] / lisp / progmodes / xref.el
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1 ;; xref.el --- Cross-referencing commands -*-lexical-binding:t-*-
3 ;; Copyright (C) 2014-2015 Free Software Foundation, Inc.
5 ;; This file is part of GNU Emacs.
7 ;; GNU Emacs is free software: you can redistribute it and/or modify
8 ;; it under the terms of the GNU General Public License as published by
9 ;; the Free Software Foundation, either version 3 of the License, or
10 ;; (at your option) any later version.
12 ;; GNU Emacs is distributed in the hope that it will be useful,
13 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
14 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 ;; GNU General Public License for more details.
17 ;; You should have received a copy of the GNU General Public License
18 ;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
20 ;;; Commentary:
22 ;; This file provides a somewhat generic infrastructure for cross
23 ;; referencing commands, in particular "find-definition".
25 ;; Some part of the functionality must be implemented in a language
26 ;; dependent way and that's done by defining `xref-find-function',
27 ;; `xref-identifier-at-point-function' and
28 ;; `xref-identifier-completion-table-function', which see.
30 ;; A major mode should make these variables buffer-local first.
32 ;; `xref-find-function' can be called in several ways, see its
33 ;; description. It has to operate with "xref" and "location" values.
35 ;; One would usually call `make-xref' and `xref-make-file-location',
36 ;; `xref-make-buffer-location' or `xref-make-bogus-location' to create
37 ;; them. More generally, a location must be an instance of an EIEIO
38 ;; class inheriting from `xref-location' and implementing
39 ;; `xref-location-group' and `xref-location-marker'.
41 ;; Each identifier must be represented as a string. Implementers can
42 ;; use string properties to store additional information about the
43 ;; identifier, but they should keep in mind that values returned from
44 ;; `xref-identifier-completion-table-function' should still be
45 ;; distinct, because the user can't see the properties when making the
46 ;; choice.
48 ;; See the functions `etags-xref-find' and `elisp-xref-find' for full
49 ;; examples.
51 ;;; Code:
53 (require 'cl-lib)
54 (require 'eieio)
55 (require 'ring)
56 (require 'pcase)
58 (defgroup xref nil "Cross-referencing commands"
59 :group 'tools)
62 ;;; Locations
64 (defclass xref-location () ()
65 :documentation "A location represents a position in a file or buffer.")
67 ;; If a backend decides to subclass xref-location it can provide
68 ;; methods for some of the following functions:
69 (cl-defgeneric xref-location-marker (location)
70 "Return the marker for LOCATION.")
72 (cl-defgeneric xref-location-group (location)
73 "Return a string used to group a set of locations.
74 This is typically the filename.")
76 ;;;; Commonly needed location classes are defined here:
78 ;; FIXME: might be useful to have an optional "hint" i.e. a string to
79 ;; search for in case the line number is sightly out of date.
80 (defclass xref-file-location (xref-location)
81 ((file :type string :initarg :file)
82 (line :type fixnum :initarg :line)
83 (column :type fixnum :initarg :column))
84 :documentation "A file location is a file/line/column triple.
85 Line numbers start from 1 and columns from 0.")
87 (defun xref-make-file-location (file line column)
88 "Create and return a new xref-file-location."
89 (make-instance 'xref-file-location :file file :line line :column column))
91 (cl-defmethod xref-location-marker ((l xref-file-location))
92 (with-slots (file line column) l
93 (with-current-buffer
94 (or (get-file-buffer file)
95 (let ((find-file-suppress-same-file-warnings t))
96 (find-file-noselect file)))
97 (save-restriction
98 (widen)
99 (save-excursion
100 (goto-char (point-min))
101 (beginning-of-line line)
102 (move-to-column column)
103 (point-marker))))))
105 (cl-defmethod xref-location-group ((l xref-file-location))
106 (oref l :file))
108 (defclass xref-buffer-location (xref-location)
109 ((buffer :type buffer :initarg :buffer)
110 (position :type fixnum :initarg :position)))
112 (defun xref-make-buffer-location (buffer position)
113 "Create and return a new xref-buffer-location."
114 (make-instance 'xref-buffer-location :buffer buffer :position position))
116 (cl-defmethod xref-location-marker ((l xref-buffer-location))
117 (with-slots (buffer position) l
118 (let ((m (make-marker)))
119 (move-marker m position buffer))))
121 (cl-defmethod xref-location-group ((l xref-buffer-location))
122 (with-slots (buffer) l
123 (or (buffer-file-name buffer)
124 (format "(buffer %s)" (buffer-name buffer)))))
126 (defclass xref-bogus-location (xref-location)
127 ((message :type string :initarg :message
128 :reader xref-bogus-location-message))
129 :documentation "Bogus locations are sometimes useful to
130 indicate errors, e.g. when we know that a function exists but the
131 actual location is not known.")
133 (defun xref-make-bogus-location (message)
134 "Create and return a new xref-bogus-location."
135 (make-instance 'xref-bogus-location :message message))
137 (cl-defmethod xref-location-marker ((l xref-bogus-location))
138 (user-error "%s" (oref l :message)))
140 (cl-defmethod xref-location-group ((_ xref-bogus-location)) "(No location)")
142 ;; This should be in elisp-mode.el, but it's preloaded, and we can't
143 ;; preload defclass and defmethod (at least, not yet).
144 (defclass xref-elisp-location (xref-location)
145 ((symbol :type symbol :initarg :symbol)
146 (type :type symbol :initarg :type)
147 (file :type string :initarg :file
148 :reader xref-location-group))
149 :documentation "Location of an Emacs Lisp symbol definition.")
151 (defun xref-make-elisp-location (symbol type file)
152 (make-instance 'xref-elisp-location :symbol symbol :type type :file file))
154 (cl-defmethod xref-location-marker ((l xref-elisp-location))
155 (with-slots (symbol type file) l
156 (let ((buffer-point
157 (pcase type
158 (`defun (find-function-search-for-symbol symbol nil file))
159 ((or `defvar `defface)
160 (find-function-search-for-symbol symbol type file))
161 (`feature
162 (cons (find-file-noselect file) 1)))))
163 (with-current-buffer (car buffer-point)
164 (goto-char (or (cdr buffer-point) (point-min)))
165 (point-marker)))))
168 ;;; Cross-reference
170 (defclass xref--xref ()
171 ((description :type string :initarg :description
172 :reader xref--xref-description)
173 (location :type xref-location :initarg :location
174 :reader xref--xref-location))
175 :comment "An xref is used to display and locate constructs like
176 variables or functions.")
178 (defun xref-make (description location)
179 "Create and return a new xref.
180 DESCRIPTION is a short string to describe the xref.
181 LOCATION is an `xref-location'."
182 (make-instance 'xref--xref :description description :location location))
185 ;;; API
187 (declare-function etags-xref-find "etags" (action id))
188 (declare-function tags-lazy-completion-table "etags" ())
190 ;; For now, make the etags backend the default.
191 (defvar xref-find-function #'etags-xref-find
192 "Function to look for cross-references.
193 It can be called in several ways:
195 (definitions IDENTIFIER): Find definitions of IDENTIFIER. The
196 result must be a list of xref objects. If no definitions can be
197 found, return nil.
199 (references IDENTIFIER): Find references of IDENTIFIER. The
200 result must be a list of xref objects. If no references can be
201 found, return nil.
203 (apropos PATTERN): Find all symbols that match PATTERN. PATTERN
204 is a regexp.
206 IDENTIFIER can be any string returned by
207 `xref-identifier-at-point-function', or from the table returned
208 by `xref-identifier-completion-table-function'.
210 To create an xref object, call `xref-make'.")
212 (defvar xref-identifier-at-point-function #'xref-default-identifier-at-point
213 "Function to get the relevant identifier at point.
215 The return value must be a string or nil. nil means no
216 identifier at point found.
218 If it's hard to determine the identifier precisely (e.g., because
219 it's a method call on unknown type), the implementation can
220 return a simple string (such as symbol at point) marked with a
221 special text property which `xref-find-function' would recognize
222 and then delegate the work to an external process.")
224 (defvar xref-identifier-completion-table-function #'tags-lazy-completion-table
225 "Function that returns the completion table for identifiers.")
227 (defun xref-default-identifier-at-point ()
228 (let ((thing (thing-at-point 'symbol)))
229 (and thing (substring-no-properties thing))))
232 ;;; misc utilities
233 (defun xref--alistify (list key test)
234 "Partition the elements of LIST into an alist.
235 KEY extracts the key from an element and TEST is used to compare
236 keys."
237 (let ((alist '()))
238 (dolist (e list)
239 (let* ((k (funcall key e))
240 (probe (cl-assoc k alist :test test)))
241 (if probe
242 (setcdr probe (cons e (cdr probe)))
243 (push (cons k (list e)) alist))))
244 ;; Put them back in order.
245 (cl-loop for (key . value) in (reverse alist)
246 collect (cons key (reverse value)))))
248 (defun xref--insert-propertized (props &rest strings)
249 "Insert STRINGS with text properties PROPS."
250 (let ((start (point)))
251 (apply #'insert strings)
252 (add-text-properties start (point) props)))
254 (defun xref--search-property (property &optional backward)
255 "Search the next text range where text property PROPERTY is non-nil.
256 Return the value of PROPERTY. If BACKWARD is non-nil, search
257 backward."
258 (let ((next (if backward
259 #'previous-single-char-property-change
260 #'next-single-char-property-change))
261 (start (point))
262 (value nil))
263 (while (progn
264 (goto-char (funcall next (point) property))
265 (not (or (setq value (get-text-property (point) property))
266 (eobp)
267 (bobp)))))
268 (cond (value)
269 (t (goto-char start) nil))))
272 ;;; Marker stack (M-. pushes, M-, pops)
274 (defcustom xref-marker-ring-length 16
275 "Length of the xref marker ring."
276 :type 'integer
277 :version "25.1")
279 (defvar xref--marker-ring (make-ring xref-marker-ring-length)
280 "Ring of markers to implement the marker stack.")
282 (defun xref-push-marker-stack ()
283 "Add point to the marker stack."
284 (ring-insert xref--marker-ring (point-marker)))
286 ;;;###autoload
287 (defun xref-pop-marker-stack ()
288 "Pop back to where \\[xref-find-definitions] was last invoked."
289 (interactive)
290 (let ((ring xref--marker-ring))
291 (when (ring-empty-p ring)
292 (error "Marker stack is empty"))
293 (let ((marker (ring-remove ring 0)))
294 (switch-to-buffer (or (marker-buffer marker)
295 (error "The marked buffer has been deleted")))
296 (goto-char (marker-position marker))
297 (set-marker marker nil nil))))
299 ;; etags.el needs this
300 (defun xref-clear-marker-stack ()
301 "Discard all markers from the marker stack."
302 (let ((ring xref--marker-ring))
303 (while (not (ring-empty-p ring))
304 (let ((marker (ring-remove ring)))
305 (set-marker marker nil nil)))))
307 ;;;###autoload
308 (defun xref-marker-stack-empty-p ()
309 "Return t if the marker stack is empty; nil otherwise."
310 (ring-empty-p xref--marker-ring))
313 (defun xref--goto-location (location)
314 "Set buffer and point according to xref-location LOCATION."
315 (let ((marker (xref-location-marker location)))
316 (set-buffer (marker-buffer marker))
317 (cond ((and (<= (point-min) marker) (<= marker (point-max))))
318 (widen-automatically (widen))
319 (t (error "Location is outside accessible part of buffer")))
320 (goto-char marker)))
322 (defun xref--pop-to-location (location &optional window)
323 "Goto xref-location LOCATION and display the buffer.
324 WINDOW controls how the buffer is displayed:
325 nil -- switch-to-buffer
326 'window -- pop-to-buffer (other window)
327 'frame -- pop-to-buffer (other frame)"
328 (xref--goto-location location)
329 (cl-ecase window
330 ((nil) (switch-to-buffer (current-buffer)))
331 (window (pop-to-buffer (current-buffer) t))
332 (frame (let ((pop-up-frames t)) (pop-to-buffer (current-buffer) t)))))
335 ;;; XREF buffer (part of the UI)
337 ;; The xref buffer is used to display a set of xrefs.
339 (defvar-local xref--display-history nil
340 "List of pairs (BUFFER . WINDOW), for temporarily displayed buffers.")
342 (defvar-local xref--temporary-buffers nil
343 "List of buffers created by xref code.")
345 (defvar-local xref--current nil
346 "Non-nil if this buffer was once current, except while displaying xrefs.
347 Used for temporary buffers.")
349 (defvar xref--inhibit-mark-current nil)
351 (defun xref--mark-selected ()
352 (unless xref--inhibit-mark-current
353 (setq xref--current t))
354 (remove-hook 'buffer-list-update-hook #'xref--mark-selected t))
356 (defun xref--save-to-history (buf win)
357 (let ((restore (window-parameter win 'quit-restore)))
358 ;; Save the new entry if the window displayed another buffer
359 ;; previously.
360 (when (and restore (not (eq (car restore) 'same)))
361 (push (cons buf win) xref--display-history))))
363 (defun xref--display-position (pos other-window recenter-arg xref-buf)
364 ;; Show the location, but don't hijack focus.
365 (with-selected-window (display-buffer (current-buffer) other-window)
366 (goto-char pos)
367 (recenter recenter-arg)
368 (let ((buf (current-buffer))
369 (win (selected-window)))
370 (with-current-buffer xref-buf
371 (setq-local other-window-scroll-buffer buf)
372 (xref--save-to-history buf win)))))
374 (defun xref--show-location (location)
375 (condition-case err
376 (let ((xref-buf (current-buffer))
377 (bl (buffer-list))
378 (xref--inhibit-mark-current t))
379 (xref--goto-location location)
380 (let ((buf (current-buffer)))
381 (unless (memq buf bl)
382 ;; Newly created.
383 (add-hook 'buffer-list-update-hook #'xref--mark-selected nil t)
384 (with-current-buffer xref-buf
385 (push buf xref--temporary-buffers))))
386 (xref--display-position (point) t 1 xref-buf))
387 (user-error (message (error-message-string err)))))
389 (defun xref-show-location-at-point ()
390 "Display the source of xref at point in the other window, if any."
391 (interactive)
392 (let ((loc (xref--location-at-point)))
393 (when loc
394 (xref--show-location loc))))
396 (defun xref-next-line ()
397 "Move to the next xref and display its source in the other window."
398 (interactive)
399 (xref--search-property 'xref-location)
400 (xref-show-location-at-point))
402 (defun xref-prev-line ()
403 "Move to the previous xref and display its source in the other window."
404 (interactive)
405 (xref--search-property 'xref-location t)
406 (xref-show-location-at-point))
408 (defun xref--location-at-point ()
409 (get-text-property (point) 'xref-location))
411 (defvar-local xref--window nil
412 "ACTION argument to call `display-buffer' with.")
414 (defun xref-goto-xref ()
415 "Jump to the xref on the current line and bury the xref buffer."
416 (interactive)
417 (back-to-indentation)
418 (let ((loc (or (xref--location-at-point)
419 (user-error "No reference at point")))
420 (window xref--window))
421 (xref-quit)
422 (xref--pop-to-location loc window)))
424 (defvar xref--xref-buffer-mode-map
425 (let ((map (make-sparse-keymap)))
426 (define-key map [remap quit-window] #'xref-quit)
427 (define-key map (kbd "n") #'xref-next-line)
428 (define-key map (kbd "p") #'xref-prev-line)
429 (define-key map (kbd "RET") #'xref-goto-xref)
430 (define-key map (kbd "C-o") #'xref-show-location-at-point)
431 ;; suggested by Johan Claesson "to further reduce finger movement":
432 (define-key map (kbd ".") #'xref-next-line)
433 (define-key map (kbd ",") #'xref-prev-line)
434 map))
436 (define-derived-mode xref--xref-buffer-mode special-mode "XREF"
437 "Mode for displaying cross-references."
438 (setq buffer-read-only t))
440 (defun xref-quit (&optional kill)
441 "Bury temporarily displayed buffers, then quit the current window.
443 If KILL is non-nil, kill all buffers that were created in the
444 process of showing xrefs, and also kill the current buffer.
446 The buffers that the user has otherwise interacted with in the
447 meantime are preserved."
448 (interactive "P")
449 (let ((window (selected-window))
450 (history xref--display-history))
451 (setq xref--display-history nil)
452 (pcase-dolist (`(,buf . ,win) history)
453 (when (and (window-live-p win)
454 (eq buf (window-buffer win)))
455 (quit-window nil win)))
456 (when kill
457 (let ((xref--inhibit-mark-current t)
458 kill-buffer-query-functions)
459 (dolist (buf xref--temporary-buffers)
460 (unless (buffer-local-value 'xref--current buf)
461 (kill-buffer buf)))
462 (setq xref--temporary-buffers nil)))
463 (quit-window kill window)))
465 (defconst xref-buffer-name "*xref*"
466 "The name of the buffer to show xrefs.")
468 (defvar xref--button-map
469 (let ((map (make-sparse-keymap)))
470 (define-key map [(control ?m)] #'xref-goto-xref)
471 (define-key map [mouse-1] #'xref-goto-xref)
472 (define-key map [mouse-2] #'xref--mouse-2)
473 map))
475 (defun xref--mouse-2 (event)
476 "Move point to the button and show the xref definition."
477 (interactive "e")
478 (mouse-set-point event)
479 (forward-line 0)
480 (xref--search-property 'xref-location)
481 (xref-show-location-at-point))
483 (defun xref--insert-xrefs (xref-alist)
484 "Insert XREF-ALIST in the current-buffer.
485 XREF-ALIST is of the form ((GROUP . (XREF ...)) ...). Where
486 GROUP is a string for decoration purposes and XREF is an
487 `xref--xref' object."
488 (cl-loop for ((group . xrefs) . more1) on xref-alist do
489 (xref--insert-propertized '(face bold) group "\n")
490 (cl-loop for (xref . more2) on xrefs do
491 (insert " ")
492 (with-slots (description location) xref
493 (xref--insert-propertized
494 (list 'xref-location location
495 'face 'font-lock-keyword-face
496 'mouse-face 'highlight
497 'keymap xref--button-map
498 'help-echo
499 (concat "mouse-2: display in another window, "
500 "RET or mouse-1: follow reference"))
501 description))
502 (when (or more1 more2)
503 (insert "\n")))))
505 (defun xref--analyze (xrefs)
506 "Find common filenames in XREFS.
507 Return an alist of the form ((FILENAME . (XREF ...)) ...)."
508 (xref--alistify xrefs
509 (lambda (x)
510 (xref-location-group (xref--xref-location x)))
511 #'equal))
513 (defun xref--show-xref-buffer (xrefs alist)
514 (let ((xref-alist (xref--analyze xrefs)))
515 (with-current-buffer (get-buffer-create xref-buffer-name)
516 (let ((inhibit-read-only t))
517 (erase-buffer)
518 (xref--insert-xrefs xref-alist)
519 (xref--xref-buffer-mode)
520 (pop-to-buffer (current-buffer))
521 (goto-char (point-min))
522 (setq xref--window (assoc-default 'window alist))
523 (setq xref--temporary-buffers (assoc-default 'temporary-buffers alist))
524 (dolist (buf xref--temporary-buffers)
525 (with-current-buffer buf
526 (add-hook 'buffer-list-update-hook #'xref--mark-selected nil t)))
527 (current-buffer)))))
530 ;; This part of the UI seems fairly uncontroversial: it reads the
531 ;; identifier and deals with the single definition case.
533 ;; The controversial multiple definitions case is handed off to
534 ;; xref-show-xrefs-function.
536 (defvar xref-show-xrefs-function 'xref--show-xref-buffer
537 "Function to display a list of xrefs.")
539 (defvar xref--read-identifier-history nil)
541 (defvar xref--read-pattern-history nil)
543 (defun xref--show-xrefs (input kind arg window)
544 (let* ((bl (buffer-list))
545 (xrefs (funcall xref-find-function kind arg))
546 (tb (cl-set-difference (buffer-list) bl)))
547 (cond
548 ((null xrefs)
549 (user-error "No known %s for: %s" (symbol-name kind) input))
550 ((not (cdr xrefs))
551 (xref-push-marker-stack)
552 (xref--pop-to-location (xref--xref-location (car xrefs)) window))
554 (xref-push-marker-stack)
555 (funcall xref-show-xrefs-function xrefs
556 `((window . ,window)
557 (temporary-buffers . ,tb)))))))
559 (defun xref--read-identifier (prompt)
560 "Return the identifier at point or read it from the minibuffer."
561 (let ((id (funcall xref-identifier-at-point-function)))
562 (cond ((or current-prefix-arg (not id))
563 (completing-read prompt
564 (funcall xref-identifier-completion-table-function)
565 nil t id
566 'xref--read-identifier-history))
567 (t id))))
570 ;;; Commands
572 (defun xref--find-definitions (id window)
573 (xref--show-xrefs id 'definitions id window))
575 ;;;###autoload
576 (defun xref-find-definitions (identifier)
577 "Find the definition of the identifier at point.
578 With prefix argument or when there's no identifier at point,
579 prompt for it."
580 (interactive (list (xref--read-identifier "Find definitions of: ")))
581 (xref--find-definitions identifier nil))
583 ;;;###autoload
584 (defun xref-find-definitions-other-window (identifier)
585 "Like `xref-find-definitions' but switch to the other window."
586 (interactive (list (xref--read-identifier "Find definitions of: ")))
587 (xref--find-definitions identifier 'window))
589 ;;;###autoload
590 (defun xref-find-definitions-other-frame (identifier)
591 "Like `xref-find-definitions' but switch to the other frame."
592 (interactive (list (xref--read-identifier "Find definitions of: ")))
593 (xref--find-definitions identifier 'frame))
595 ;;;###autoload
596 (defun xref-find-references (identifier)
597 "Find references to the identifier at point.
598 With prefix argument, prompt for the identifier."
599 (interactive (list (xref--read-identifier "Find references of: ")))
600 (xref--show-xrefs identifier 'references identifier nil))
602 (declare-function apropos-parse-pattern "apropos" (pattern))
604 ;;;###autoload
605 (defun xref-find-apropos (pattern)
606 "Find all meaningful symbols that match PATTERN.
607 The argument has the same meaning as in `apropos'."
608 (interactive (list (read-from-minibuffer
609 "Search for pattern (word list or regexp): "
610 nil nil nil 'xref--read-pattern-history)))
611 (require 'apropos)
612 (xref--show-xrefs pattern 'apropos
613 (apropos-parse-pattern
614 (if (string-equal (regexp-quote pattern) pattern)
615 ;; Split into words
616 (or (split-string pattern "[ \t]+" t)
617 (user-error "No word list given"))
618 pattern))
619 nil))
622 ;;; Key bindings
624 ;;;###autoload (define-key esc-map "." #'xref-find-definitions)
625 ;;;###autoload (define-key esc-map "," #'xref-pop-marker-stack)
626 ;;;###autoload (define-key esc-map [?\C-.] #'xref-find-apropos)
627 ;;;###autoload (define-key ctl-x-4-map "." #'xref-find-definitions-other-window)
628 ;;;###autoload (define-key ctl-x-5-map "." #'xref-find-definitions-other-frame)
631 (provide 'xref)
633 ;;; xref.el ends here