(eval-when-compile (require 'cl))
(defstruct (ewoc--node
(:type vector) (:constructor ewoc--node-create (start-marker data)))
left right data start-marker)
(defalias 'ewoc--node-branch 'aref)
(defun ewoc--dll-create ()
"Create an empty doubly linked list."
(let ((dummy-node (ewoc--node-create 'DL-LIST 'DL-LIST)))
(setf (ewoc--node-right dummy-node) dummy-node)
(setf (ewoc--node-left dummy-node) dummy-node)
dummy-node))
(defun ewoc--node-enter-before (node elemnode)
"Insert ELEMNODE before NODE in a DLL."
(assert (and (null (ewoc--node-left elemnode)) (null (ewoc--node-right elemnode))))
(setf (ewoc--node-left elemnode) (ewoc--node-left node))
(setf (ewoc--node-right elemnode) node)
(setf (ewoc--node-right (ewoc--node-left node)) elemnode)
(setf (ewoc--node-left node) elemnode))
(defun ewoc--node-enter-first (dll node)
"Add a free floating NODE first in DLL."
(ewoc--node-enter-before (ewoc--node-right dll) node))
(defun ewoc--node-enter-last (dll node)
"Add a free floating NODE last in DLL."
(ewoc--node-enter-before dll node))
(defun ewoc--node-next (dll node)
"Return the node after NODE, or nil if NODE is the last node."
(unless (eq (ewoc--node-right node) dll) (ewoc--node-right node)))
(defun ewoc--node-prev (dll node)
"Return the node before NODE, or nil if NODE is the first node."
(unless (eq (ewoc--node-left node) dll) (ewoc--node-left node)))
(defun ewoc--node-delete (node)
"Unbind NODE from its doubly linked list and return it."
(setf (ewoc--node-right (ewoc--node-left node)) (ewoc--node-right node))
(setf (ewoc--node-left (ewoc--node-right node)) (ewoc--node-left node))
(setf (ewoc--node-left node) nil)
(setf (ewoc--node-right node) nil)
node)
(defun ewoc--node-nth (dll n)
"Return the Nth node from the doubly linked list DLL.
N counts from zero. If DLL is not that long, nil is returned.
If N is negative, return the -(N+1)th last element.
Thus, (ewoc--node-nth dll 0) returns the first node,
and (ewoc--node-nth dll -1) returns the last node."
(let* ((branch (if (< n 0) 0 1))
(node (ewoc--node-branch dll branch)))
(if (< n 0) (setq n (- -1 n)))
(while (and (not (eq dll node)) (> n 0))
(setq node (ewoc--node-branch node branch))
(setq n (1- n)))
(unless (eq dll node) node)))
(defun ewoc-location (node)
"Return the start location of NODE."
(ewoc--node-start-marker node))
(defstruct (ewoc
(:constructor nil)
(:constructor ewoc--create
(buffer pretty-printer header footer dll))
(:conc-name ewoc--))
buffer pretty-printer header footer dll last-node)
(defmacro ewoc--set-buffer-bind-dll-let* (ewoc varlist &rest forms)
"Execute FORMS with ewoc--buffer selected as current buffer,
dll bound to ewoc--dll, and VARLIST bound as in a let*.
dll will be bound when VARLIST is initialized, but the current
buffer will *not* have been changed.
Return value of last form in FORMS."
(let ((old-buffer (make-symbol "old-buffer"))
(hnd (make-symbol "ewoc")))
(` (let* (((, old-buffer) (current-buffer))
((, hnd) (, ewoc))
(dll (ewoc--dll (, hnd)))
(,@ varlist))
(set-buffer (ewoc--buffer (, hnd)))
(unwind-protect
(progn (,@ forms))
(set-buffer (, old-buffer)))))))
(defmacro ewoc--set-buffer-bind-dll (ewoc &rest forms)
`(ewoc--set-buffer-bind-dll-let* ,ewoc nil ,@forms))
(defsubst ewoc--filter-hf-nodes (ewoc node)
"Evaluate NODE once and return it.
BUT if it is the header or the footer in EWOC return nil instead."
(unless (or (eq node (ewoc--header ewoc))
(eq node (ewoc--footer ewoc)))
node))
(defun ewoc--create-node (data pretty-printer pos)
"Call PRETTY-PRINTER with point set at POS in current buffer.
Remember the start position. Create a wrapper containing that
start position and the element DATA."
(save-excursion
(when (markerp pos) (setq pos (marker-position pos)))
(goto-char pos)
(let ((inhibit-read-only t))
(insert-before-markers ?\n)
(backward-char 1)
(funcall pretty-printer data)
(ewoc--node-create (copy-marker pos) data))))
(defun ewoc--delete-node-internal (ewoc node)
"Delete a data string from EWOC.
Can not be used on the footer. Returns the wrapper that is deleted.
The start-marker in the wrapper is set to nil, so that it doesn't
consume any more resources."
(let ((dll (ewoc--dll ewoc))
(inhibit-read-only t))
(if (eq (ewoc--last-node ewoc) node)
(setf (ewoc--last-node ewoc) nil))
(delete-region (ewoc--node-start-marker node)
(ewoc--node-start-marker (ewoc--node-next dll node)))
(set-marker (ewoc--node-start-marker node) nil)
(ewoc--node-delete node)))
(defun ewoc--refresh-node (pp node)
"Redisplay the element represented by NODE using the pretty-printer PP."
(let ((inhibit-read-only t))
(save-excursion
(delete-region (ewoc--node-start-marker node)
(1- (marker-position
(ewoc--node-start-marker (ewoc--node-right node)))))
(goto-char (ewoc--node-start-marker node))
(funcall pp (ewoc--node-data node)))))
(defun ewoc-create (pretty-printer &optional header footer)
"Create an empty ewoc.
The ewoc will be inserted in the current buffer at the current position.
PRETTY-PRINTER should be a function that takes one argument, an
element, and inserts a string representing it in the buffer (at
point). The string PRETTY-PRINTER inserts may be empty or span
several linse. A trailing newline will always be inserted
automatically. The PRETTY-PRINTER should use insert, and not
insert-before-markers.
Optional third argument HEADER is a string that will always be
present at the top of the ewoc. HEADER should end with a
newline. Optionaly fourth argument FOOTER is similar, and will
be inserted at the bottom of the ewoc."
(let ((new-ewoc
(ewoc--create (current-buffer)
pretty-printer nil nil (ewoc--dll-create)))
(pos (point)))
(ewoc--set-buffer-bind-dll new-ewoc
(unless header (setq header ""))
(unless footer (setq footer ""))
(setf (ewoc--node-start-marker dll) (copy-marker pos))
(let ((foot (ewoc--create-node footer (lambda (x) (insert footer)) pos))
(head (ewoc--create-node header (lambda (x) (insert header)) pos)))
(ewoc--node-enter-first dll head)
(ewoc--node-enter-last dll foot)
(setf (ewoc--header new-ewoc) head)
(setf (ewoc--footer new-ewoc) foot)))
new-ewoc))
(defalias 'ewoc-data 'ewoc--node-data)
(defun ewoc-enter-first (ewoc data)
"Enter DATA first in EWOC."
(ewoc--set-buffer-bind-dll ewoc
(ewoc-enter-after ewoc (ewoc--node-nth dll 0) data)))
(defun ewoc-enter-last (ewoc data)
"Enter DATA last in EWOC."
(ewoc--set-buffer-bind-dll ewoc
(ewoc-enter-before ewoc (ewoc--node-nth dll -1) data)))
(defun ewoc-enter-after (ewoc node data)
"Enter a new element DATA after NODE in EWOC.
Returns the new NODE."
(ewoc--set-buffer-bind-dll ewoc
(ewoc-enter-before ewoc (ewoc--node-next dll node) data)))
(defun ewoc-enter-before (ewoc node data)
"Enter a new element DATA before NODE in EWOC.
Returns the new NODE."
(ewoc--set-buffer-bind-dll ewoc
(ewoc--node-enter-before
node
(ewoc--create-node
data
(ewoc--pretty-printer ewoc)
(ewoc--node-start-marker node)))))
(defun ewoc-next (ewoc node)
"Get the next node.
Returns nil if NODE is nil or the last element."
(when node
(ewoc--filter-hf-nodes
ewoc (ewoc--node-next (ewoc--dll ewoc) node))))
(defun ewoc-prev (ewoc node)
"Get the previous node.
Returns nil if NODE is nil or the first element."
(when node
(ewoc--filter-hf-nodes
ewoc
(ewoc--node-prev (ewoc--dll ewoc) node))))
(defun ewoc-nth (ewoc n)
"Return the Nth node.
N counts from zero. Nil is returned if there is less than N elements.
If N is negative, return the -(N+1)th last element.
Thus, (ewoc-nth dll 0) returns the first node,
and (ewoc-nth dll -1) returns the last node.
Use `ewoc--node-data' to extract the data from the node."
(setq n (if (< n 0) (1- n) (1+ n)))
(ewoc--filter-hf-nodes ewoc
(ewoc--node-nth (ewoc--dll ewoc) n)))
(defun ewoc-map (map-function ewoc &rest args)
"Apply MAP-FUNCTION to all elements in EWOC.
MAP-FUNCTION is applied to the first element first.
If MAP-FUNCTION returns non-nil the element will be refreshed (its
pretty-printer will be called once again).
Note that the buffer for EWOC will be current buffer when MAP-FUNCTION
is called. MAP-FUNCTION must restore the current buffer to BUFFER before
it returns, if it changes it.
If more than two arguments are given, the remaining
arguments will be passed to MAP-FUNCTION."
(ewoc--set-buffer-bind-dll-let* ewoc
((footer (ewoc--footer ewoc))
(node (ewoc--node-nth dll 1)))
(while (not (eq node footer))
(if (apply map-function (ewoc--node-data node) args)
(ewoc--refresh-node (ewoc--pretty-printer ewoc) node))
(setq node (ewoc--node-next dll node)))))
(defun ewoc-filter (ewoc predicate &rest args)
"Remove all elements in EWOC for which PREDICATE returns nil.
Note that the buffer for EWOC will be current-buffer when PREDICATE
is called. PREDICATE must restore the current buffer before it returns
if it changes it.
The PREDICATE is called with the element as its first argument. If any
ARGS are given they will be passed to the PREDICATE."
(ewoc--set-buffer-bind-dll-let* ewoc
((node (ewoc--node-nth dll 1))
(footer (ewoc--footer ewoc))
(next nil))
(while (not (eq node footer))
(setq next (ewoc--node-next dll node))
(unless (apply predicate (ewoc--node-data node) args)
(ewoc--delete-node-internal ewoc node))
(setq node next))))
(defun ewoc-locate (ewoc &optional pos guess)
"Return the node that POS (a buffer position) is within.
POS may be a marker or an integer. It defaults to point.
GUESS should be a node that it is likely that POS is near.
If POS points before the first element, the first node is returned.
If POS points after the last element, the last node is returned.
If the EWOC is empty, nil is returned."
(unless pos (setq pos (point)))
(ewoc--set-buffer-bind-dll-let* ewoc
((footer (ewoc--footer ewoc)))
(cond
((eq (ewoc--node-nth dll 1) (ewoc--node-nth dll -1))
nil)
((< pos (ewoc--node-start-marker (ewoc--node-nth dll 2)))
(ewoc--node-nth dll 1))
((>= pos (ewoc--node-start-marker (ewoc--node-nth dll -2)))
(ewoc--node-nth dll -2))
(t
(let* ((best-guess (ewoc--node-nth dll 1))
(distance (abs (- pos (ewoc--node-start-marker best-guess)))))
(when guess
(let ((d (abs (- pos (ewoc--node-start-marker guess)))))
(when (< d distance)
(setq distance d)
(setq best-guess guess))))
(let* ((g (ewoc--node-nth dll -1)) (d (abs (- pos (ewoc--node-start-marker g)))))
(when (< d distance)
(setq distance d)
(setq best-guess g)))
(when (ewoc--last-node ewoc) (let* ((g (ewoc--last-node ewoc))
(d (abs (- pos (ewoc--node-start-marker g)))))
(when (< d distance)
(setq distance d)
(setq best-guess g))))
(cond
((>= pos
(ewoc--node-start-marker best-guess))
(while (>= pos (ewoc--node-start-marker best-guess))
(setq best-guess (ewoc--node-next dll best-guess)))
(ewoc--node-prev dll best-guess))
(t
(while (< pos (ewoc--node-start-marker best-guess))
(setq best-guess (ewoc--node-prev dll best-guess)))
best-guess)))))))
(defun ewoc-invalidate (ewoc &rest nodes)
"Refresh some elements.
The pretty-printer that for EWOC will be called for all NODES."
(ewoc--set-buffer-bind-dll ewoc
(dolist (node nodes)
(ewoc--refresh-node (ewoc--pretty-printer ewoc) node))))
(defun ewoc-goto-prev (ewoc arg)
"Move point to the ARGth previous element.
Don't move if we are at the first element, or if EWOC is empty.
Returns the node we moved to."
(ewoc--set-buffer-bind-dll-let* ewoc
((node (ewoc-locate ewoc (point))))
(when node
(when (>= (point) (ewoc--node-start-marker (ewoc--node-right node)))
(setq arg (1- arg)))
(while (and node (> arg 0))
(setq arg (1- arg))
(setq node (ewoc--node-prev dll node)))
(unless (ewoc--filter-hf-nodes ewoc node)
(setq node (ewoc--node-nth dll 1)))
(ewoc-goto-node ewoc node))))
(defun ewoc-goto-next (ewoc arg)
"Move point to the ARGth next element.
Returns the node (or nil if we just passed the last node)."
(ewoc--set-buffer-bind-dll-let* ewoc
((node (ewoc-locate ewoc (point))))
(while (and node (> arg 0))
(setq arg (1- arg))
(setq node (ewoc--node-next dll node)))
(ewoc-goto-node ewoc node)))
(defun ewoc-goto-node (ewoc node)
"Move point to NODE."
(ewoc--set-buffer-bind-dll ewoc
(goto-char (ewoc--node-start-marker node))
(if goal-column (move-to-column goal-column))
(setf (ewoc--last-node ewoc) node)))
(defun ewoc-refresh (ewoc)
"Refresh all data in EWOC.
The pretty-printer that was specified when the EWOC was created
will be called for all elements in EWOC.
Note that `ewoc-invalidate' is more efficient if only a small
number of elements needs to be refreshed."
(ewoc--set-buffer-bind-dll-let* ewoc
((footer (ewoc--footer ewoc)))
(let ((inhibit-read-only t))
(delete-region (ewoc--node-start-marker (ewoc--node-nth dll 1))
(ewoc--node-start-marker footer))
(goto-char (ewoc--node-start-marker footer))
(let ((node (ewoc--node-nth dll 1)))
(while (not (eq node footer))
(set-marker (ewoc--node-start-marker node) (point))
(funcall (ewoc--pretty-printer ewoc)
(ewoc--node-data node))
(insert "\n")
(setq node (ewoc--node-next dll node)))))
(set-marker (ewoc--node-start-marker footer) (point))))
(defun ewoc-collect (ewoc predicate &rest args)
"Select elements from EWOC using PREDICATE.
Return a list of all selected data elements.
PREDICATE is a function that takes a data element as its first argument.
The elements on the returned list will appear in the same order as in
the buffer. You should not rely on in which order PREDICATE is
called.
Note that the buffer the EWOC is displayed in is current-buffer
when PREDICATE is called. If PREDICATE must restore current-buffer if
it changes it.
If more than two arguments are given the
remaining arguments will be passed to PREDICATE."
(ewoc--set-buffer-bind-dll-let* ewoc
((header (ewoc--header ewoc))
(node (ewoc--node-nth dll -2))
result)
(while (not (eq node header))
(if (apply predicate (ewoc--node-data node) args)
(push (ewoc--node-data node) result))
(setq node (ewoc--node-prev dll node)))
(nreverse result)))
(defun ewoc-buffer (ewoc)
"Return the buffer that is associated with EWOC.
Returns nil if the buffer has been deleted."
(let ((buf (ewoc--buffer ewoc)))
(when (buffer-name buf) buf)))
(defun ewoc-get-hf (ewoc)
"Return a cons cell containing the (HEADER . FOOTER) of EWOC."
(cons (ewoc--node-data (ewoc--header ewoc))
(ewoc--node-data (ewoc--footer ewoc))))
(defun ewoc-set-hf (ewoc header footer)
"Set the HEADER and FOOTER of EWOC."
(setf (ewoc--node-data (ewoc--header ewoc)) header)
(setf (ewoc--node-data (ewoc--footer ewoc)) footer)
(ewoc--refresh-node (lambda (x) (insert header)) (ewoc--header ewoc))
(ewoc--refresh-node (lambda (x) (insert footer)) (ewoc--footer ewoc)))
(provide 'ewoc)