Function: org-fold-core--property-symbol-get-create

org-fold-core--property-symbol-get-create is a byte-compiled function defined in org-fold-core.el.gz.

Signature

(org-fold-core--property-symbol-get-create SPEC &optional BUFFER RETURN-ONLY)

Documentation

Return a unique symbol suitable as folding text property.

Return value is unique for folding SPEC in BUFFER. If the buffer already have buffer-local setup in char-property-alias-alist and the setup appears to be created for different buffer, copy the old invisibility state into new buffer-local text properties, unless RETURN-ONLY is non-nil.

Source Code

;; Defined in /usr/src/emacs/lisp/org/org-fold-core.el.gz
;; This is the core function used to fold text in buffers.  We use
;; text properties to hide folded text, however 'invisible property is
;; not directly used (unless risky `org-fold-core--optimize-for-huge-buffers' is
;; enabled). Instead, we define unique text property (folding
;; property) for every possible folding spec and add the resulting
;; text properties into `char-property-alias-alist', so that
;; 'invisible text property is automatically defined if any of the
;; folding properties is non-nil.  This approach lets us maintain
;; multiple folds for the same text region - poor man's overlays (but
;; much faster).  Additionally, folding properties are ensured to be
;; unique for different buffers (especially for indirect
;; buffers). This is done to allow different folding states in
;; indirect buffers.
(defun org-fold-core--property-symbol-get-create (spec &optional buffer return-only)
  "Return a unique symbol suitable as folding text property.
Return value is unique for folding SPEC in BUFFER.
If the buffer already have buffer-local setup in `char-property-alias-alist'
and the setup appears to be created for different buffer,
copy the old invisibility state into new buffer-local text properties,
unless RETURN-ONLY is non-nil."
  (if (eq org-fold-core-style 'overlays)
      (or (gethash (cons 'global spec) org-fold-core--property-symbol-cache)
          (puthash (cons 'global spec)
                   (org-fold-core-get-folding-property-symbol spec nil 'global)
                   org-fold-core--property-symbol-cache))
    (let* ((buf (or buffer (current-buffer))))
      ;; Create unique property symbol for SPEC in BUFFER
      (let ((local-prop (or (gethash (cons buf spec) org-fold-core--property-symbol-cache)
			    (puthash (cons buf spec)
                                     (org-fold-core-get-folding-property-symbol
                                      spec buf
                                      (org-fold-core-get-folding-spec-property spec :global))
                                     org-fold-core--property-symbol-cache))))
        (prog1
            local-prop
          (unless return-only
	    (with-current-buffer buf
              ;; Update folding properties carried over from other
              ;; buffer (implying that current buffer is indirect
              ;; buffer). Normally, `char-property-alias-alist' in new
              ;; indirect buffer is a copy of the same variable from
              ;; the base buffer. Then, `char-property-alias-alist'
              ;; would contain folding properties, which are not
              ;; matching the generated `local-prop'.
	      (unless (member local-prop (cdr (assq 'invisible char-property-alias-alist)))
                ;; Copy all the old folding properties to preserve the folding state
                (with-silent-modifications
                  (dolist (old-prop (cdr (assq 'invisible char-property-alias-alist)))
                    (org-with-wide-buffer
                     (let* ((pos (point-min))
                            (spec (org-fold-core-get-folding-spec-from-folding-prop old-prop))
                            ;; Generate new buffer-unique folding property
                            (new-prop (when spec (org-fold-core--property-symbol-get-create spec nil 'return-only))))
                       ;; Copy the visibility state for `spec' from `old-prop' to `new-prop'
                       (unless (eq old-prop new-prop)
                         (while (< pos (point-max))
                           (let ((val (get-text-property pos old-prop))
                                 (next (next-single-char-property-change pos old-prop)))
                             (when val
                               (put-text-property pos next new-prop val))
                             (setq pos next)))))))
                  ;; Update `char-property-alias-alist' with folding
                  ;; properties unique for the current buffer.
                  (setq-local char-property-alias-alist
                              (cons (cons 'invisible
                                          (mapcar (lambda (spec)
                                                    (org-fold-core--property-symbol-get-create spec nil 'return-only))
                                                  (org-fold-core-folding-spec-list)))
                                    (remove (assq 'invisible char-property-alias-alist)
                                            char-property-alias-alist)))
                  ;; Set folding property stickiness according to
                  ;; their `:font-sticky' and `:rear-sticky'
                  ;; parameters.
                  (let (full-prop-list)
                    (org-fold-core-cycle-over-indirect-buffers
                      (setq full-prop-list
                            (append full-prop-list
                                    (delq nil
                                          (mapcar (lambda (spec)
                                                    (cond
                                                     ((org-fold-core-get-folding-spec-property spec :front-sticky)
                                                      (cons (org-fold-core--property-symbol-get-create spec nil 'return-only)
                                                            nil))
                                                     ((org-fold-core-get-folding-spec-property spec :rear-sticky)
                                                      nil)
                                                     (t
                                                      (cons (org-fold-core--property-symbol-get-create spec nil 'return-only)
                                                            t))))
                                                  (org-fold-core-folding-spec-list))))))
                    (org-fold-core-cycle-over-indirect-buffers
                      (setq-local text-property-default-nonsticky
                                  (delete-dups (append
                                                text-property-default-nonsticky
                                                full-prop-list))))))))))))))