code.delx.au - gnu-emacs/blob - lisp/progmodes/xref.el

   1 ;; xref.el --- Cross-referencing commands              -*-lexical-binding:t-*-
   2
   3 ;; Copyright (C) 2014-2015 Free Software Foundation, Inc.
   4
   5 ;; This file is part of GNU Emacs.
   6
   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.
  11
  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.
  16
  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/>.
  19
  20 ;;; Commentary:
  21
  22 ;; This file provides a somewhat generic infrastructure for cross
  23 ;; referencing commands, in particular "find-definition".
  24 ;;
  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.
  29 ;;
  30 ;; A major mode should make these variables buffer-local first.
  31 ;;
  32 ;; `xref-find-function' can be called in several ways, see its
  33 ;; description.  It has to operate with "xref" and "location" values.
  34 ;;
  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'.
  40 ;;
  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.
  47 ;;
  48 ;; See the functions `etags-xref-find' and `elisp-xref-find' for full
  49 ;; examples.
  50
  51 ;;; Code:
  52
  53 (require 'cl-lib)
  54 (require 'eieio)
  55 (require 'ring)
  56 (require 'pcase)
  57 (require 'project)
  58
  59 (defgroup xref nil "Cross-referencing commands"
  60   :group 'tools)
  61
  62 \f
  63 ;;; Locations
  64
  65 (defclass xref-location () ()
  66   :documentation "A location represents a position in a file or buffer.")
  67
  68 ;; If a backend decides to subclass xref-location it can provide
  69 ;; methods for some of the following functions:
  70 (cl-defgeneric xref-location-marker (location)
  71   "Return the marker for LOCATION.")
  72
  73 (cl-defgeneric xref-location-group (location)
  74   "Return a string used to group a set of locations.
  75 This is typically the filename.")
  76
  77 (cl-defgeneric xref-location-line (_location)
  78   "Return the line number corresponding to the location."
  79   nil)
  80
  81 (cl-defgeneric xref-match-bounds (_item)
  82   "Return a cons with columns of the beginning and end of the match."
  83   nil)
  84
  85 ;;;; Commonly needed location classes are defined here:
  86
  87 ;; FIXME: might be useful to have an optional "hint" i.e. a string to
  88 ;; search for in case the line number is sightly out of date.
  89 (defclass xref-file-location (xref-location)
  90   ((file :type string :initarg :file)
  91    (line :type fixnum :initarg :line :reader xref-location-line)
  92    (column :type fixnum :initarg :column :reader xref-file-location-column))
  93   :documentation "A file location is a file/line/column triple.
  94 Line numbers start from 1 and columns from 0.")
  95
  96 (defun xref-make-file-location (file line column)
  97   "Create and return a new xref-file-location."
  98   (make-instance 'xref-file-location :file file :line line :column column))
  99
 100 (cl-defmethod xref-location-marker ((l xref-file-location))
 101   (with-slots (file line column) l
 102     (with-current-buffer
 103         (or (get-file-buffer file)
 104             (let ((find-file-suppress-same-file-warnings t))
 105               (find-file-noselect file)))
 106       (save-restriction
 107         (widen)
 108         (save-excursion
 109           (goto-char (point-min))
 110           (beginning-of-line line)
 111           (move-to-column column)
 112           (point-marker))))))
 113
 114 (cl-defmethod xref-location-group ((l xref-file-location))
 115   (oref l file))
 116
 117 (defclass xref-buffer-location (xref-location)
 118   ((buffer :type buffer :initarg :buffer)
 119    (position :type fixnum :initarg :position)))
 120
 121 (defun xref-make-buffer-location (buffer position)
 122   "Create and return a new xref-buffer-location."
 123   (make-instance 'xref-buffer-location :buffer buffer :position position))
 124
 125 (cl-defmethod xref-location-marker ((l xref-buffer-location))
 126   (with-slots (buffer position) l
 127     (let ((m (make-marker)))
 128       (move-marker m position buffer))))
 129
 130 (cl-defmethod xref-location-group ((l xref-buffer-location))
 131   (with-slots (buffer) l
 132     (or (buffer-file-name buffer)
 133         (format "(buffer %s)" (buffer-name buffer)))))
 134
 135 (defclass xref-bogus-location (xref-location)
 136   ((message :type string :initarg :message
 137             :reader xref-bogus-location-message))
 138   :documentation "Bogus locations are sometimes useful to
 139 indicate errors, e.g. when we know that a function exists but the
 140 actual location is not known.")
 141
 142 (defun xref-make-bogus-location (message)
 143   "Create and return a new xref-bogus-location."
 144   (make-instance 'xref-bogus-location :message message))
 145
 146 (cl-defmethod xref-location-marker ((l xref-bogus-location))
 147   (user-error "%s" (oref l message)))
 148
 149 (cl-defmethod xref-location-group ((_ xref-bogus-location)) "(No location)")
 150
 151 \f
 152 ;;; Cross-reference
 153
 154 (defclass xref-item ()
 155   ((summary :type string :initarg :summary
 156             :reader xref-item-summary
 157             :documentation "One line which will be displayed for
 158 this item in the output buffer.")
 159    (location :initarg :location
 160              :reader xref-item-location
 161              :documentation "An object describing how to navigate
 162 to the reference's target."))
 163   :comment "An xref item describes a reference to a location
 164 somewhere.")
 165
 166 (defun xref-make (summary location)
 167   "Create and return a new xref item.
 168 SUMMARY is a short string to describe the xref.
 169 LOCATION is an `xref-location'."
 170   (make-instance 'xref-item :summary summary :location location))
 171
 172 (defclass xref-match-item ()
 173   ((summary :type string :initarg :summary
 174             :reader xref-item-summary)
 175    (location :initarg :location
 176              :type xref-file-location
 177              :reader xref-item-location)
 178    (end-column :initarg :end-column))
 179   :comment "An xref item describes a reference to a location
 180 somewhere.")
 181
 182 (cl-defmethod xref-match-bounds ((i xref-match-item))
 183   (with-slots (end-column location) i
 184     (cons (xref-file-location-column location)
 185           end-column)))
 186
 187 (defun xref-make-match (summary end-column location)
 188   "Create and return a new xref match item.
 189 SUMMARY is a short string to describe the xref.
 190 END-COLUMN is the match end column number inside SUMMARY.
 191 LOCATION is an `xref-location'."
 192   (make-instance 'xref-match-item :summary summary :location location
 193                  :end-column end-column))
 194
 195 \f
 196 ;;; API
 197
 198 (declare-function etags-xref-find "etags" (action id))
 199 (declare-function tags-lazy-completion-table "etags" ())
 200
 201 ;; For now, make the etags backend the default.
 202 (defvar xref-find-function #'etags-xref-find
 203   "Function to look for cross-references.
 204 It can be called in several ways:
 205
 206  (definitions IDENTIFIER): Find definitions of IDENTIFIER.  The
 207 result must be a list of xref objects.  If no definitions can be
 208 found, return nil.
 209
 210  (references IDENTIFIER): Find references of IDENTIFIER.  The
 211 result must be a list of xref objects.  If no references can be
 212 found, return nil.
 213
 214  (apropos PATTERN): Find all symbols that match PATTERN.  PATTERN
 215 is a regexp.
 216
 217 IDENTIFIER can be any string returned by
 218 `xref-identifier-at-point-function', or from the table returned
 219 by `xref-identifier-completion-table-function'.
 220
 221 To create an xref object, call `xref-make'.")
 222
 223 (defvar xref-identifier-at-point-function #'xref-default-identifier-at-point
 224   "Function to get the relevant identifier at point.
 225
 226 The return value must be a string or nil.  nil means no
 227 identifier at point found.
 228
 229 If it's hard to determine the identifier precisely (e.g., because
 230 it's a method call on unknown type), the implementation can
 231 return a simple string (such as symbol at point) marked with a
 232 special text property which `xref-find-function' would recognize
 233 and then delegate the work to an external process.")
 234
 235 (defvar xref-identifier-completion-table-function #'tags-lazy-completion-table
 236   "Function that returns the completion table for identifiers.")
 237
 238 (defun xref-default-identifier-at-point ()
 239   (let ((thing (thing-at-point 'symbol)))
 240     (and thing (substring-no-properties thing))))
 241
 242 \f
 243 ;;; misc utilities
 244 (defun xref--alistify (list key test)
 245   "Partition the elements of LIST into an alist.
 246 KEY extracts the key from an element and TEST is used to compare
 247 keys."
 248   (let ((alist '()))
 249     (dolist (e list)
 250       (let* ((k (funcall key e))
 251              (probe (cl-assoc k alist :test test)))
 252         (if probe
 253             (setcdr probe (cons e (cdr probe)))
 254           (push (cons k (list e)) alist))))
 255     ;; Put them back in order.
 256     (cl-loop for (key . value) in (reverse alist)
 257              collect (cons key (reverse value)))))
 258
 259 (defun xref--insert-propertized (props &rest strings)
 260   "Insert STRINGS with text properties PROPS."
 261   (let ((start (point)))
 262     (apply #'insert strings)
 263     (add-text-properties start (point) props)))
 264
 265 (defun xref--search-property (property &optional backward)
 266     "Search the next text range where text property PROPERTY is non-nil.
 267 Return the value of PROPERTY.  If BACKWARD is non-nil, search
 268 backward."
 269   (let ((next (if backward
 270                   #'previous-single-char-property-change
 271                 #'next-single-char-property-change))
 272         (start (point))
 273         (value nil))
 274     (while (progn
 275              (goto-char (funcall next (point) property))
 276              (not (or (setq value (get-text-property (point) property))
 277                       (eobp)
 278                       (bobp)))))
 279     (cond (value)
 280           (t (goto-char start) nil))))
 281
 282 \f
 283 ;;; Marker stack  (M-. pushes, M-, pops)
 284
 285 (defcustom xref-marker-ring-length 16
 286   "Length of the xref marker ring."
 287   :type 'integer)
 288
 289 (defcustom xref-prompt-for-identifier '(not xref-find-definitions
 290                                             xref-find-definitions-other-window
 291                                             xref-find-definitions-other-frame)
 292   "When t, always prompt for the identifier name.
 293
 294 When nil, prompt only when there's no value at point we can use,
 295 or when the command has been called with the prefix argument.
 296
 297 Otherwise, it's a list of xref commands which will prompt
 298 anyway (the value at point, if any, will be used as the default).
 299
 300 If the list starts with `not', the meaning of the rest of the
 301 elements is negated."
 302   :type '(choice (const :tag "always" t)
 303                  (const :tag "auto" nil)
 304                  (set :menu-tag "command specific" :tag "commands"
 305                       :value (not)
 306                       (const :tag "Except" not)
 307                       (repeat :inline t (symbol :tag "command")))))
 308
 309 (defcustom xref-after-jump-hook '(recenter
 310                                   xref-pulse-momentarily)
 311   "Functions called after jumping to an xref."
 312   :type 'hook)
 313
 314 (defcustom xref-after-return-hook '(xref-pulse-momentarily)
 315   "Functions called after returning to a pre-jump location."
 316   :type 'hook)
 317
 318 (defvar xref--marker-ring (make-ring xref-marker-ring-length)
 319   "Ring of markers to implement the marker stack.")
 320
 321 (defun xref-push-marker-stack (&optional m)
 322   "Add point M (defaults to `point-marker') to the marker stack."
 323   (ring-insert xref--marker-ring (or m (point-marker))))
 324
 325 ;;;###autoload
 326 (defun xref-pop-marker-stack ()
 327   "Pop back to where \\[xref-find-definitions] was last invoked."
 328   (interactive)
 329   (let ((ring xref--marker-ring))
 330     (when (ring-empty-p ring)
 331       (error "Marker stack is empty"))
 332     (let ((marker (ring-remove ring 0)))
 333       (switch-to-buffer (or (marker-buffer marker)
 334                             (error "The marked buffer has been deleted")))
 335       (goto-char (marker-position marker))
 336       (set-marker marker nil nil)
 337       (run-hooks 'xref-after-return-hook))))
 338
 339 (defvar xref--current-item nil)
 340
 341 (defun xref-pulse-momentarily ()
 342   (pcase-let ((`(,beg . ,end)
 343                (save-excursion
 344                  (or
 345                   (xref--match-buffer-bounds xref--current-item)
 346                   (back-to-indentation)
 347                   (if (eolp)
 348                       (cons (line-beginning-position) (1+ (point)))
 349                     (cons (point) (line-end-position)))))))
 350     (pulse-momentary-highlight-region beg end 'next-error)))
 351
 352 (defun xref--match-buffer-bounds (item)
 353   (save-excursion
 354     (let ((bounds (xref-match-bounds item)))
 355       (when bounds
 356         (cons (progn (move-to-column (car bounds))
 357                      (point))
 358               (progn (move-to-column (cdr bounds))
 359                      (point)))))))
 360
 361 ;; etags.el needs this
 362 (defun xref-clear-marker-stack ()
 363   "Discard all markers from the marker stack."
 364   (let ((ring xref--marker-ring))
 365     (while (not (ring-empty-p ring))
 366       (let ((marker (ring-remove ring)))
 367         (set-marker marker nil nil)))))
 368
 369 ;;;###autoload
 370 (defun xref-marker-stack-empty-p ()
 371   "Return t if the marker stack is empty; nil otherwise."
 372   (ring-empty-p xref--marker-ring))
 373
 374 \f
 375 (defun xref--goto-location (location)
 376   "Set buffer and point according to xref-location LOCATION."
 377   (let ((marker (xref-location-marker location)))
 378     (set-buffer (marker-buffer marker))
 379     (cond ((and (<= (point-min) marker) (<= marker (point-max))))
 380           (widen-automatically (widen))
 381           (t (error "Location is outside accessible part of buffer")))
 382     (goto-char marker)))
 383
 384 (defun xref--pop-to-location (item &optional window)
 385   "Go to the location of ITEM and display the buffer.
 386 WINDOW controls how the buffer is displayed:
 387   nil      -- switch-to-buffer
 388   'window  -- pop-to-buffer (other window)
 389   'frame   -- pop-to-buffer (other frame)"
 390   (xref--goto-location (xref-item-location item))
 391   (cl-ecase window
 392     ((nil)  (switch-to-buffer (current-buffer)))
 393     (window (pop-to-buffer (current-buffer) t))
 394     (frame  (let ((pop-up-frames t)) (pop-to-buffer (current-buffer) t))))
 395   (let ((xref--current-item item))
 396     (run-hooks 'xref-after-jump-hook)))
 397
 398 \f
 399 ;;; XREF buffer (part of the UI)
 400
 401 ;; The xref buffer is used to display a set of xrefs.
 402
 403 (defvar-local xref--display-history nil
 404   "List of pairs (BUFFER . WINDOW), for temporarily displayed buffers.")
 405
 406 (defvar-local xref--temporary-buffers nil
 407   "List of buffers created by xref code.")
 408
 409 (defvar-local xref--current nil
 410   "Non-nil if this buffer was once current, except while displaying xrefs.
 411 Used for temporary buffers.")
 412
 413 (defvar xref--inhibit-mark-current nil)
 414
 415 (defun xref--mark-selected ()
 416   (unless xref--inhibit-mark-current
 417     (setq xref--current t))
 418   (remove-hook 'buffer-list-update-hook #'xref--mark-selected t))
 419
 420 (defun xref--save-to-history (buf win)
 421   (let ((restore (window-parameter win 'quit-restore)))
 422     ;; Save the new entry if the window displayed another buffer
 423     ;; previously.
 424     (when (and restore (not (eq (car restore) 'same)))
 425       (push (cons buf win) xref--display-history))))
 426
 427 (defun xref--display-position (pos other-window xref-buf)
 428   ;; Show the location, but don't hijack focus.
 429   (with-selected-window (display-buffer (current-buffer) other-window)
 430     (goto-char pos)
 431     (run-hooks 'xref-after-jump-hook)
 432     (let ((buf (current-buffer))
 433           (win (selected-window)))
 434       (with-current-buffer xref-buf
 435         (setq-local other-window-scroll-buffer buf)
 436         (xref--save-to-history buf win)))))
 437
 438 (defun xref--show-location (location)
 439   (condition-case err
 440       (let ((xref-buf (current-buffer))
 441             (bl (buffer-list))
 442             (xref--inhibit-mark-current t))
 443         (xref--goto-location location)
 444         (let ((buf (current-buffer)))
 445           (unless (memq buf bl)
 446             ;; Newly created.
 447             (add-hook 'buffer-list-update-hook #'xref--mark-selected nil t)
 448             (with-current-buffer xref-buf
 449               (push buf xref--temporary-buffers))))
 450         (xref--display-position (point) t xref-buf))
 451     (user-error (message (error-message-string err)))))
 452
 453 (defun xref-show-location-at-point ()
 454   "Display the source of xref at point in the other window, if any."
 455   (interactive)
 456   (let* ((xref (xref--item-at-point))
 457          (xref--current-item xref))
 458     (when xref
 459       (xref--show-location (xref-item-location xref)))))
 460
 461 (defun xref-next-line ()
 462   "Move to the next xref and display its source in the other window."
 463   (interactive)
 464   (xref--search-property 'xref-item)
 465   (xref-show-location-at-point))
 466
 467 (defun xref-prev-line ()
 468   "Move to the previous xref and display its source in the other window."
 469   (interactive)
 470   (xref--search-property 'xref-item t)
 471   (xref-show-location-at-point))
 472
 473 (defun xref--item-at-point ()
 474   (save-excursion
 475     (back-to-indentation)
 476     (get-text-property (point) 'xref-item)))
 477
 478 (defvar-local xref--window nil
 479   "ACTION argument to call `display-buffer' with.")
 480
 481 (defun xref-goto-xref ()
 482   "Jump to the xref on the current line and bury the xref buffer."
 483   (interactive)
 484   (let ((xref (or (xref--item-at-point)
 485                  (user-error "No reference at point")))
 486         (window xref--window))
 487     (xref-quit)
 488     (xref--pop-to-location xref window)))
 489
 490 (defun xref-query-replace (from to)
 491   "Perform interactive replacement in all current matches."
 492   (interactive
 493    (list (read-regexp "Query replace regexp in matches" ".*")
 494          (read-regexp "Replace with: ")))
 495   (let (pairs item)
 496     (unwind-protect
 497         (progn
 498           (save-excursion
 499             (goto-char (point-min))
 500             ;; TODO: Check that none of the matches are out of date;
 501             ;; offer to re-scan otherwise.  Note that saving the last
 502             ;; modification tick won't work, as long as not all of the
 503             ;; buffers are kept open.
 504             (while (setq item (xref--search-property 'xref-item))
 505               (when (xref-match-bounds item)
 506                 (save-excursion
 507                   (xref--goto-location (xref-item-location item))
 508                   (let ((bounds (xref--match-buffer-bounds item))
 509                         (beg (make-marker))
 510                         (end (make-marker)))
 511                     (move-marker beg (car bounds))
 512                     (move-marker end (cdr bounds))
 513                     (push (cons beg end) pairs)))))
 514             (setq pairs (nreverse pairs)))
 515           (unless pairs (user-error "No suitable matches here"))
 516           (xref--query-replace-1 from to pairs))
 517       (dolist (pair pairs)
 518         (move-marker (car pair) nil)
 519         (move-marker (cdr pair) nil)))))
 520
 521 (defun xref--query-replace-1 (from to pairs)
 522   (let* ((query-replace-lazy-highlight nil)
 523          current-pair current-buf
 524          ;; Counteract the "do the next match now" hack in
 525          ;; `perform-replace'.  And still, it'll report that those
 526          ;; matches were "filtered out" at the end.
 527          (isearch-filter-predicate
 528           (lambda (beg end)
 529             (and current-pair
 530                  (eq (current-buffer) current-buf)
 531                  (>= beg (car current-pair))
 532                  (<= end (cdr current-pair)))))
 533          (replace-re-search-function
 534           (lambda (from &optional _bound noerror)
 535             (let (found)
 536               (while (and (not found) pairs)
 537                 (setq current-pair (pop pairs)
 538                       current-buf  (marker-buffer (car current-pair)))
 539                 (pop-to-buffer current-buf)
 540                 (goto-char (car current-pair))
 541                 (when (re-search-forward from (cdr current-pair) noerror)
 542                   (setq found t)))
 543               found))))
 544     ;; FIXME: Despite this being a multi-buffer replacement, `N'
 545     ;; doesn't work, because we're not using
 546     ;; `multi-query-replace-map', and it would expect the below
 547     ;; function to be called once per buffer.
 548     (perform-replace from to t t nil)))
 549
 550 (defvar xref--xref-buffer-mode-map
 551   (let ((map (make-sparse-keymap)))
 552     (define-key map [remap quit-window] #'xref-quit)
 553     (define-key map (kbd "n") #'xref-next-line)
 554     (define-key map (kbd "p") #'xref-prev-line)
 555     (define-key map (kbd "r") #'xref-query-replace)
 556     (define-key map (kbd "RET") #'xref-goto-xref)
 557     (define-key map (kbd "C-o") #'xref-show-location-at-point)
 558     ;; suggested by Johan Claesson "to further reduce finger movement":
 559     (define-key map (kbd ".") #'xref-next-line)
 560     (define-key map (kbd ",") #'xref-prev-line)
 561     map))
 562
 563 (define-derived-mode xref--xref-buffer-mode special-mode "XREF"
 564   "Mode for displaying cross-references."
 565   (setq buffer-read-only t)
 566   (setq next-error-function #'xref--next-error-function)
 567   (setq next-error-last-buffer (current-buffer)))
 568
 569 (defun xref--next-error-function (n reset?)
 570   (when reset?
 571     (goto-char (point-min)))
 572   (let ((backward (< n 0))
 573         (n (abs n))
 574         (xref nil))
 575     (dotimes (_ n)
 576       (setq xref (xref--search-property 'xref-item backward)))
 577     (cond (xref
 578            (xref--pop-to-location xref))
 579           (t
 580            (error "No %s xref" (if backward "previous" "next"))))))
 581
 582 (defun xref-quit (&optional kill)
 583   "Bury temporarily displayed buffers, then quit the current window.
 584
 585 If KILL is non-nil, kill all buffers that were created in the
 586 process of showing xrefs, and also kill the current buffer.
 587
 588 The buffers that the user has otherwise interacted with in the
 589 meantime are preserved."
 590   (interactive "P")
 591   (let ((window (selected-window))
 592         (history xref--display-history))
 593     (setq xref--display-history nil)
 594     (pcase-dolist (`(,buf . ,win) history)
 595       (when (and (window-live-p win)
 596                  (eq buf (window-buffer win)))
 597         (quit-window nil win)))
 598     (when kill
 599       (let ((xref--inhibit-mark-current t)
 600             kill-buffer-query-functions)
 601         (dolist (buf xref--temporary-buffers)
 602           (unless (buffer-local-value 'xref--current buf)
 603             (kill-buffer buf)))
 604         (setq xref--temporary-buffers nil)))
 605     (quit-window kill window)))
 606
 607 (defconst xref-buffer-name "*xref*"
 608   "The name of the buffer to show xrefs.")
 609
 610 (defvar xref--button-map
 611   (let ((map (make-sparse-keymap)))
 612     (define-key map [(control ?m)] #'xref-goto-xref)
 613     (define-key map [mouse-1] #'xref-goto-xref)
 614     (define-key map [mouse-2] #'xref--mouse-2)
 615     map))
 616
 617 (defun xref--mouse-2 (event)
 618   "Move point to the button and show the xref definition."
 619   (interactive "e")
 620   (mouse-set-point event)
 621   (forward-line 0)
 622   (xref--search-property 'xref-item)
 623   (xref-show-location-at-point))
 624
 625 (defun xref--insert-xrefs (xref-alist)
 626   "Insert XREF-ALIST in the current-buffer.
 627 XREF-ALIST is of the form ((GROUP . (XREF ...)) ...).  Where
 628 GROUP is a string for decoration purposes and XREF is an
 629 `xref-item' object."
 630   (require 'compile) ; For the compilation faces.
 631   (cl-loop for ((group . xrefs) . more1) on xref-alist
 632            for max-line-width =
 633            (cl-loop for xref in xrefs
 634                     maximize (let ((line (xref-location-line
 635                                           (oref xref location))))
 636                                (length (and line (format "%d" line)))))
 637            for line-format = (and max-line-width
 638                                   (format "%%%dd: " max-line-width))
 639            do
 640            (xref--insert-propertized '(face compilation-info) group "\n")
 641            (cl-loop for (xref . more2) on xrefs do
 642                     (with-slots (summary location) xref
 643                       (let* ((line (xref-location-line location))
 644                              (prefix
 645                               (if line
 646                                   (propertize (format line-format line)
 647                                               'face 'compilation-line-number)
 648                                 "  ")))
 649                         (xref--insert-propertized
 650                          (list 'xref-item xref
 651                                ;; 'face 'font-lock-keyword-face
 652                                'mouse-face 'highlight
 653                                'keymap xref--button-map
 654                                'help-echo
 655                                (concat "mouse-2: display in another window, "
 656                                        "RET or mouse-1: follow reference"))
 657                          prefix summary)))
 658                     (insert "\n"))))
 659
 660 (defun xref--analyze (xrefs)
 661   "Find common filenames in XREFS.
 662 Return an alist of the form ((FILENAME . (XREF ...)) ...)."
 663   (xref--alistify xrefs
 664                   (lambda (x)
 665                     (xref-location-group (xref-item-location x)))
 666                   #'equal))
 667
 668 (defun xref--show-xref-buffer (xrefs alist)
 669   (let ((xref-alist (xref--analyze xrefs)))
 670     (with-current-buffer (get-buffer-create xref-buffer-name)
 671       (let ((inhibit-read-only t))
 672         (erase-buffer)
 673         (xref--insert-xrefs xref-alist)
 674         (xref--xref-buffer-mode)
 675         (pop-to-buffer (current-buffer))
 676         (goto-char (point-min))
 677         (setq xref--window (assoc-default 'window alist))
 678         (setq xref--temporary-buffers (assoc-default 'temporary-buffers alist))
 679         (dolist (buf xref--temporary-buffers)
 680           (with-current-buffer buf
 681             (add-hook 'buffer-list-update-hook #'xref--mark-selected nil t)))
 682         (current-buffer)))))
 683
 684 \f
 685 ;; This part of the UI seems fairly uncontroversial: it reads the
 686 ;; identifier and deals with the single definition case.
 687 ;;
 688 ;; The controversial multiple definitions case is handed off to
 689 ;; xref-show-xrefs-function.
 690
 691 (defvar xref-show-xrefs-function 'xref--show-xref-buffer
 692   "Function to display a list of xrefs.")
 693
 694 (defvar xref--read-identifier-history nil)
 695
 696 (defvar xref--read-pattern-history nil)
 697
 698 (defun xref--show-xrefs (input kind arg window)
 699   (let* ((bl (buffer-list))
 700          (xrefs (funcall xref-find-function kind arg))
 701          (tb (cl-set-difference (buffer-list) bl)))
 702     (cond
 703      ((null xrefs)
 704       (user-error "No %s found for: %s" (symbol-name kind) input))
 705      ((not (cdr xrefs))
 706       (xref-push-marker-stack)
 707       (xref--pop-to-location (car xrefs) window))
 708      (t
 709       (xref-push-marker-stack)
 710       (funcall xref-show-xrefs-function xrefs
 711                `((window . ,window)
 712                  (temporary-buffers . ,tb)))))))
 713
 714 (defun xref--prompt-p (command)
 715   (or (eq xref-prompt-for-identifier t)
 716       (if (eq (car xref-prompt-for-identifier) 'not)
 717           (not (memq command (cdr xref-prompt-for-identifier)))
 718         (memq command xref-prompt-for-identifier))))
 719
 720 (defun xref--read-identifier (prompt)
 721   "Return the identifier at point or read it from the minibuffer."
 722   (let ((id (funcall xref-identifier-at-point-function)))
 723     (cond ((or current-prefix-arg
 724                (not id)
 725                (xref--prompt-p this-command))
 726            (completing-read (if id
 727                                 (format "%s (default %s): "
 728                                         (substring prompt 0 (string-match
 729                                                              "[ :]+\\'" prompt))
 730                                         id)
 731                               prompt)
 732                             (funcall xref-identifier-completion-table-function)
 733                             nil nil nil
 734                             'xref--read-identifier-history id))
 735           (t id))))
 736
 737 \f
 738 ;;; Commands
 739
 740 (defun xref--find-definitions (id window)
 741   (xref--show-xrefs id 'definitions id window))
 742
 743 ;;;###autoload
 744 (defun xref-find-definitions (identifier)
 745   "Find the definition of the identifier at point.
 746 With prefix argument or when there's no identifier at point,
 747 prompt for it."
 748   (interactive (list (xref--read-identifier "Find definitions of: ")))
 749   (xref--find-definitions identifier nil))
 750
 751 ;;;###autoload
 752 (defun xref-find-definitions-other-window (identifier)
 753   "Like `xref-find-definitions' but switch to the other window."
 754   (interactive (list (xref--read-identifier "Find definitions of: ")))
 755   (xref--find-definitions identifier 'window))
 756
 757 ;;;###autoload
 758 (defun xref-find-definitions-other-frame (identifier)
 759   "Like `xref-find-definitions' but switch to the other frame."
 760   (interactive (list (xref--read-identifier "Find definitions of: ")))
 761   (xref--find-definitions identifier 'frame))
 762
 763 ;;;###autoload
 764 (defun xref-find-references (identifier)
 765   "Find references to the identifier at point.
 766 With prefix argument, prompt for the identifier."
 767   (interactive (list (xref--read-identifier "Find references of: ")))
 768   (xref--show-xrefs identifier 'references identifier nil))
 769
 770 ;; TODO: Rename and move to project-find-regexp, as soon as idiomatic
 771 ;; usage of xref from other packages has stabilized.
 772 ;;;###autoload
 773 (defun xref-find-regexp (regexp)
 774   "Find all matches for REGEXP.
 775 With \\[universal-argument] prefix, you can specify the directory
 776 to search in, and the file name pattern to search for."
 777   (interactive (list (xref--read-identifier "Find regexp: ")))
 778   (require 'grep)
 779   (let* ((proj (project-current))
 780          (files (if current-prefix-arg
 781                     (grep-read-files regexp)
 782                   "*"))
 783          (dirs (if current-prefix-arg
 784                    (list (read-directory-name "Base directory: "
 785                                               nil default-directory t))
 786                  (project-prune-directories
 787                   (append
 788                    (project-roots proj)
 789                    (project-search-path proj)))))
 790          (xref-find-function
 791           (lambda (_kind regexp)
 792             (cl-mapcan
 793              (lambda (dir)
 794                (xref-collect-matches regexp files dir
 795                                      (project-ignores proj dir)))
 796              dirs))))
 797     (xref--show-xrefs regexp 'matches regexp nil)))
 798
 799 (declare-function apropos-parse-pattern "apropos" (pattern))
 800
 801 ;;;###autoload
 802 (defun xref-find-apropos (pattern)
 803   "Find all meaningful symbols that match PATTERN.
 804 The argument has the same meaning as in `apropos'."
 805   (interactive (list (read-string
 806                       "Search for pattern (word list or regexp): "
 807                       nil 'xref--read-pattern-history)))
 808   (require 'apropos)
 809   (xref--show-xrefs pattern 'apropos
 810                     (apropos-parse-pattern
 811                      (if (string-equal (regexp-quote pattern) pattern)
 812                          ;; Split into words
 813                          (or (split-string pattern "[ \t]+" t)
 814                              (user-error "No word list given"))
 815                        pattern))
 816                     nil))
 817
 818 \f
 819 ;;; Key bindings
 820
 821 ;;;###autoload (define-key esc-map "." #'xref-find-definitions)
 822 ;;;###autoload (define-key esc-map "," #'xref-pop-marker-stack)
 823 ;;;###autoload (define-key esc-map "?" #'xref-find-references)
 824 ;;;###autoload (define-key esc-map [?\C-.] #'xref-find-apropos)
 825 ;;;###autoload (define-key ctl-x-4-map "." #'xref-find-definitions-other-window)
 826 ;;;###autoload (define-key ctl-x-5-map "." #'xref-find-definitions-other-frame)
 827
 828 \f
 829 ;;; Helper functions
 830
 831 (defvar xref-etags-mode--saved nil)
 832
 833 (define-minor-mode xref-etags-mode
 834   "Minor mode to make xref use etags again.
 835
 836 Certain major modes install their own mechanisms for listing
 837 identifiers and navigation.  Turn this on to undo those settings
 838 and just use etags."
 839   :lighter ""
 840   (if xref-etags-mode
 841       (progn
 842         (setq xref-etags-mode--saved
 843               (cons xref-find-function
 844                     xref-identifier-completion-table-function))
 845         (kill-local-variable 'xref-find-function)
 846         (kill-local-variable 'xref-identifier-completion-table-function))
 847     (setq-local xref-find-function (car xref-etags-mode--saved))
 848     (setq-local xref-identifier-completion-table-function
 849                 (cdr xref-etags-mode--saved))))
 850
 851 (declare-function semantic-symref-find-references-by-name "semantic/symref")
 852 (declare-function semantic-symref-find-text "semantic/symref")
 853 (declare-function semantic-find-file-noselect "semantic/fw")
 854 (declare-function grep-read-files "grep")
 855 (declare-function grep-expand-template "grep")
 856
 857 (defun xref-collect-references (symbol dir)
 858   "Collect references to SYMBOL inside DIR.
 859 This function uses the Semantic Symbol Reference API, see
 860 `semantic-symref-find-references-by-name' for details on which
 861 tools are used, and when."
 862   (cl-assert (directory-name-p dir))
 863   (require 'semantic/symref)
 864   (defvar semantic-symref-tool)
 865   (let* ((default-directory dir)
 866          (semantic-symref-tool 'detect)
 867          (res (semantic-symref-find-references-by-name symbol 'subdirs))
 868          (hits (and res (oref res hit-lines)))
 869          (orig-buffers (buffer-list)))
 870     (unwind-protect
 871         (delq nil
 872               (mapcar (lambda (hit) (xref--collect-match
 873                                 hit (format "\\_<%s\\_>" (regexp-quote symbol))))
 874                       hits))
 875       (mapc #'kill-buffer
 876             (cl-set-difference (buffer-list) orig-buffers)))))
 877
 878 (defun xref-collect-matches (regexp files dir ignores)
 879   "Collect matches for REGEXP inside FILES in DIR.
 880 FILES is a string with glob patterns separated by spaces.
 881 IGNORES is a list of glob patterns."
 882   (cl-assert (directory-name-p dir))
 883   (require 'semantic/fw)
 884   (grep-compute-defaults)
 885   (defvar grep-find-template)
 886   (defvar grep-highlight-matches)
 887   (let* ((grep-find-template (replace-regexp-in-string "-e " "-E "
 888                                                        grep-find-template t t))
 889          (grep-highlight-matches nil)
 890          (command (xref--rgrep-command (xref--regexp-to-extended regexp)
 891                                        files dir ignores))
 892          (orig-buffers (buffer-list))
 893          (buf (get-buffer-create " *xref-grep*"))
 894          (grep-re (caar grep-regexp-alist))
 895          hits)
 896     (with-current-buffer buf
 897       (erase-buffer)
 898       (call-process-shell-command command nil t)
 899       (goto-char (point-min))
 900       (while (re-search-forward grep-re nil t)
 901         (push (cons (string-to-number (match-string 2))
 902                     (match-string 1))
 903               hits)))
 904     (unwind-protect
 905         (delq nil
 906               (mapcar (lambda (hit) (xref--collect-match hit regexp))
 907                       (nreverse hits)))
 908       (mapc #'kill-buffer
 909             (cl-set-difference (buffer-list) orig-buffers)))))
 910
 911 (defun xref--rgrep-command (regexp files dir ignores)
 912   (require 'find-dired)      ; for `find-name-arg'
 913   (defvar grep-find-template)
 914   (defvar find-name-arg)
 915   (grep-expand-template
 916    grep-find-template
 917    regexp
 918    (concat (shell-quote-argument "(")
 919            " " find-name-arg " "
 920            (mapconcat
 921             #'shell-quote-argument
 922             (split-string files)
 923             (concat " -o " find-name-arg " "))
 924            " "
 925            (shell-quote-argument ")"))
 926    dir
 927    (concat
 928     (shell-quote-argument "(")
 929     " -path "
 930     (mapconcat
 931      (lambda (ignore)
 932        (when (string-match "\\(\\.\\)/" ignore)
 933          (setq ignore (replace-match dir t t ignore 1)))
 934        (when (string-match-p "/\\'" ignore)
 935          (setq ignore (concat ignore "*")))
 936        (unless (string-prefix-p "*" ignore)
 937          (setq ignore (concat "*/" ignore)))
 938        (shell-quote-argument ignore))
 939      ignores
 940      " -o -path ")
 941     " "
 942     (shell-quote-argument ")")
 943     " -prune -o ")))
 944
 945 (defun xref--regexp-to-extended (str)
 946   (replace-regexp-in-string
 947    ;; FIXME: Add tests.  Move to subr.el, make a public function.
 948    ;; Maybe error on Emacs-only constructs.
 949    "\\(?:\\\\\\\\\\)*\\(?:\\\\[][]\\)?\\(?:\\[.+?\\]\\|\\(\\\\?[(){}|]\\)\\)"
 950    (lambda (str)
 951      (cond
 952       ((not (match-beginning 1))
 953        str)
 954       ((eq (length (match-string 1 str)) 2)
 955        (concat (substring str 0 (match-beginning 1))
 956                (substring (match-string 1 str) 1 2)))
 957       (t
 958        (concat (substring str 0 (match-beginning 1))
 959                "\\"
 960                (match-string 1 str)))))
 961    str t t))
 962
 963 (defun xref--collect-match (hit regexp)
 964   (pcase-let* ((`(,line . ,file) hit)
 965                (buf (or (find-buffer-visiting file)
 966                         (semantic-find-file-noselect file))))
 967     (with-current-buffer buf
 968       (save-excursion
 969         (goto-char (point-min))
 970         (forward-line (1- line))
 971         (syntax-propertize (line-end-position))
 972         ;; TODO: Handle multiple matches per line.
 973         (when (re-search-forward regexp (line-end-position) t)
 974           (goto-char (match-beginning 0))
 975           (let ((loc (xref-make-file-location file line
 976                                               (current-column))))
 977             (goto-char (match-end 0))
 978             (xref-make-match (buffer-substring
 979                               (line-beginning-position)
 980                               (line-end-position))
 981                              (current-column)
 982                              loc)))))))
 983
 984 (provide 'xref)
 985
 986 ;;; xref.el ends here