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crdt.el
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crdt.el
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;;; crdt.el --- Collaborative editing using Conflict-free Replicated Data Types -*- lexical-binding: t; -*-
;; Copyright (C) 2021 Free Software Foundation, Inc.
;; Author: Qiantan Hong <qhong@alum.mit.edu>
;; Maintainer: Qiantan Hong <qhong@alum.mit.edu>
;; URL: https://code.librehq.com/qhong/crdt.el
;; Keywords: collaboration crdt
;; Version: 0.3.5
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;; This package provides a collaborative editing environment for Emacs.
;;; Code:
;;; Customs
(require 'xdg nil t)
(require 'cl-lib)
(require 'url)
(require 'color)
(require 'forms)
(require 'nadvice)
(require 'gnutls)
(defconst crdt-version "0.3.5")
(defconst crdt-protocol-version "0.3.0")
(defun crdt-version (&optional message)
"Show the crdt.el version."
(interactive (list t))
(if message
(message "crdt.el version %s" crdt-version)
crdt-version))
(defgroup crdt nil
"Collaborative editing using Conflict-free Replicated Data Types."
:prefix "crdt-"
:group 'applications)
(defcustom crdt-default-name (user-full-name)
"Default display name."
:type 'string)
(defcustom crdt-confirm-disconnect t
"Ask for confirmation when a CRDT server is to stop the connection from some client."
:type 'boolean)
(defvar crdt--log-network-traffic nil
"Debug switch to log network traffic to *Messages*.")
(defvar crdt--inhibit-recover nil
"Debug switch to disable error recovery mechanism.
This includes `crdt--with-recover' and `crdt--with-should-not-error'.")
(defcustom crdt-tuntox-executable "tuntox"
"Path to the tuntox binary."
:type 'file)
(defcustom crdt-tuntox-key-path (if (featurep 'xdg) (xdg-data-home) "~/")
"Path to save tuntox's private key."
:type 'directory)
(defcustom crdt-use-tuntox nil
"Start tuntox proxy for CRDT servers."
:type '(choice boolean (const confirm)))
(defcustom crdt-stunnel-executable "stunnel"
"Path to the stunnel binary."
:type 'file)
(defcustom crdt-tls-certificate
(locate-user-emacs-file "crdt-tls.pem")
"Path to TLS certificate file used for TLS-secured server."
:type 'file)
(defcustom crdt-tls-private-key
(locate-user-emacs-file "crdt-tls.pem")
"Path to TLS private key file used for TLS-secured server."
:type 'file)
(defcustom crdt-use-stunnel nil
"Start stunnel proxy for CRDT servers."
:type '(choice boolean (const confirm)))
(defcustom crdt-default-tls nil
"Connecting with TLS (eins) protocol by default."
:type 'boolean)
(defcustom crdt-read-settings-help-string
(concat "\\[forms-next-field]:Next Field, \\[forms-prev-field]:Prev Field\n"
"\\[forms-next-record]:History Next, \\[forms-prev-record]:History Prev\n"
"\\[exit-recursive-edit]:OK, \\[abort-recursive-edit]:Cancel\n")
"Help string for `crdt-read-settings'."
:type 'string)
(defcustom crdt-default-session-permissions
'(crdt-write-access-fcaps
crdt-create-buffer-fcaps
crdt-comint-fcaps
crdt-xscheme-fcaps
crdt-xref-fcaps)
"A list that describes default policies for public session-scoped functions.
See `crdt-new-session'.'"
:type '(list (or function symbol)))
(defcustom crdt-override-command t
"Override local commands with corresponding remote commands when available."
:type 'boolean)
(defcustom crdt-region-alpha 0.2
"Alpha value for highlighting selections."
:type 'float)
(defcustom crdt-tuntox-password-in-url nil
"Whether or not to include the session password in the tuntox connection URL.
Useful if you plan to share your session URL over a trusted secure channel. Your
password will be in plaintext in the URL, so take care when sharing URLs with
this option enabled."
:type 'boolean)
;;; Pseudo cursor/region utils
(defvar crdt-cursor-colors
(let ((n 10))
(cl-loop for i below n
for hue by (/ 1.0 n)
collect (color-hsl-to-rgb hue 0.5 0.5)))
"List of candidate cursor colors.")
(defun crdt--get-cursor-color (user-id)
"Get cursor color for USER-ID."
(apply #'color-rgb-to-hex
(nth (mod user-id (length crdt-cursor-colors)) crdt-cursor-colors)))
(defun crdt--get-region-color (user-id)
"Get region color for USER-ID."
(let ((background-rgb (color-name-to-rgb (face-attribute 'default :background))))
(if background-rgb
(apply #'color-rgb-to-hex
(cl-mapcar
(lambda (a b) (+ (* a crdt-region-alpha) (* b (- 1.0 crdt-region-alpha))))
(nth (mod user-id (length crdt-cursor-colors)) crdt-cursor-colors)
background-rgb))
(crdt--get-cursor-color user-id))))
(defun crdt--move-cursor (ov pos)
"Move pseudo cursor overlay OV to POS."
;; Hax!
(let* ((eof (eq pos (point-max)))
(end (if eof pos (1+ pos)))
(display-string
(when eof
(unless (or (eq (point) (point-max))
(cl-some (lambda (ov)
(and (eq (overlay-get ov 'category) 'crdt-pseudo-cursor)
(overlay-get ov 'before-string)))
(overlays-in (point-max) (point-max))))
(propertize " " 'face (overlay-get ov 'face))))))
(move-overlay ov pos end)
(overlay-put ov 'before-string display-string)))
(defun crdt--move-region (ov pos mark)
"Move pseudo marked region overlay OV to mark between POS and MARK."
(move-overlay ov (min pos mark) (max pos mark)))
;;; CRDT ID utils
;; CRDT IDs are represented by unibyte strings (for efficient comparison)
;; Every two bytes represent a big endian encoded integer
;; For base IDs, last two bytes are always representing site ID
;; Stored strings are BASE-ID:OFFSETs. So the last two bytes represent offset,
;; and second last two bytes represent site ID
(defconst crdt--max-value (lsh 1 16))
;; (defconst crdt--max-value 16)
;; for debug
(defconst crdt--low-byte-mask 255)
(defsubst crdt--get-two-bytes (string index)
"Get the big-endian encoded integer from STRING starting from INDEX.
INDEX is counted by bytes."
(logior (lsh (elt string index) 8)
(elt string (1+ index))))
(defsubst crdt--get-two-bytes-with-offset (string offset index default)
"Helper function for CRDT--GENERATE-ID.
Get the big-endian encoded integer from STRING starting from INDEX,
but with last two-bytes of STRING (the offset portion) replaced by OFFSET,
and padded infintely by DEFAULT to the right."
(cond ((= index (- (string-bytes string) 2))
offset)
((< (1+ index) (string-bytes string))
(logior (lsh (elt string index) 8)
(elt string (1+ index))))
(t default)))
(defsubst crdt--id-offset (id)
"Get the literal offset integer from ID.
Note that it might deviate from real offset for a character
in the middle of a block."
(crdt--get-two-bytes id (- (string-bytes id) 2)))
(defsubst crdt--set-id-offset (id offset)
"Set the OFFSET portion of ID destructively."
(let ((length (string-bytes id)))
(aset id (- length 2) (lsh offset -8))
(aset id (- length 1) (logand offset crdt--low-byte-mask))))
(defsubst crdt--id-replace-offset (id offset)
"Create and return a new id string by replacing the OFFSET portion from ID."
(let ((new-id (substring id)))
(crdt--set-id-offset new-id offset)
new-id))
(defsubst crdt--id-site (id)
"Get the site id from ID."
(crdt--get-two-bytes id (- (string-bytes id) 4)))
(defsubst crdt--generate-id (low-id low-offset high-id high-offset site-id)
"Generate a new ID between LOW-ID and HIGH-ID.
The generating site is marked as SITE-ID.
Offset parts of LOW-ID and HIGH-ID are overriden by LOW-OFFSET
and HIGH-OFFSET. (to save two copying from using CRDT--ID-REPLACE-OFFSET)"
(let* ((l (crdt--get-two-bytes-with-offset low-id low-offset 0 0))
(h (crdt--get-two-bytes-with-offset high-id high-offset 0 crdt--max-value))
(bytes (cl-loop for pos from 2 by 2
while (< (- h l) 2)
append (list (lsh l -8)
(logand l crdt--low-byte-mask))
do (setq l (crdt--get-two-bytes-with-offset low-id low-offset pos 0))
do (setq h (crdt--get-two-bytes-with-offset high-id high-offset pos crdt--max-value))))
(m (+ l 1 (random (- h l 1)))))
(apply #'unibyte-string
(append bytes (list (lsh m -8)
(logand m crdt--low-byte-mask)
(lsh site-id -8)
(logand site-id crdt--low-byte-mask)
0
0)))))
;; CRDT-ID text property actually stores a cons of (ID-STRING . END-OF-BLOCK-P)
(defsubst crdt--get-crdt-id-pair (pos &optional obj)
"Get the (CRDT-ID . END-OF-BLOCK-P) pair at POS in OBJ."
(get-text-property pos 'crdt-id obj))
(defsubst crdt--get-starting-id (pos &optional obj)
"Get the CRDT-ID object at POS in OBJ."
(car (crdt--get-crdt-id-pair pos obj)))
(defsubst crdt--end-of-block-p (pos &optional obj)
"Get the END-OF-BLOCK-P at POS in OBJ."
(cdr (crdt--get-crdt-id-pair pos obj)))
(defsubst crdt--get-starting-id-maybe (pos &optional obj limit)
"Get the CRDT-ID at POS in OBJ if POS is no smaller than LIMIT.
Return NIL otherwise."
(unless (< pos (or limit (point-min)))
(car (get-text-property pos 'crdt-id obj))))
(defsubst crdt--get-id-offset (starting-id pos &optional obj limit)
"Get the real offset integer for a character at POS.
Assume the stored literal ID is STARTING-ID."
(let* ((start-pos (previous-single-property-change (1+ pos) 'crdt-id obj (or limit (point-min)))))
(+ (- pos start-pos) (crdt--id-offset starting-id))))
;;; CRDT ID and text property utils
(defsubst crdt--get-id (pos &optional obj left-limit right-limit)
"Get the real CRDT ID at POS in OBJ.
The search for start and end of CRDT ID block is limited by LEFT-LIMIT and RIGHT-LIMIT."
(let ((right-limit (or right-limit (point-max)))
(left-limit (or left-limit (point-min))))
(cond ((>= pos right-limit) "")
((< pos left-limit) nil)
(t
(let* ((starting-id (crdt--get-starting-id pos obj))
(left-offset (crdt--get-id-offset starting-id pos obj left-limit)))
(crdt--id-replace-offset starting-id left-offset))))))
(defsubst crdt--set-id (pos id &optional end-of-block-p obj limit)
"Set the crdt ID and END-OF-BLOCK-P at POS in OBJ.
Any characters after POS but before LIMIT that used to
have the same (CRDT-ID . END-OF-BLOCK-P) pair are also updated
with ID and END-OF-BLOCK-P."
(put-text-property pos (next-single-property-change pos 'crdt-id obj (or limit (point-max))) 'crdt-id (cons id end-of-block-p) obj))
(cl-defmacro crdt--with-insertion-information
((beg end &optional beg-obj end-obj beg-limit end-limit) &body body)
"Setup some useful variables relevant to an insertion and evaluate BODY.
The insert happens between BEG in BEG-OBJ and END in END-OBJ,
if BEG-OBJ or END-OBJ is NIL, it is treated as current buffer.
The search for start and end of CRDT ID block is limited by BEG-LIMIT and END-LIMIT."
(declare (indent 1) (debug ([&rest form] body)))
`(let* ((not-begin (> ,beg ,(or beg-limit '(point-min)))) ; if it's nil, we're at the beginning of buffer
(left-pos (1- ,beg))
(starting-id-pair (when not-begin (crdt--get-crdt-id-pair left-pos ,beg-obj)))
(starting-id (if not-begin (car starting-id-pair) ""))
(left-offset (if not-begin (crdt--get-id-offset starting-id left-pos ,beg-obj ,beg-limit) 0))
(not-end (< ,end ,(or end-limit '(point-max))))
;; (beg ,beg) ; it happens that no function relies on this particular binding
(end ,end)
(beg-obj ,beg-obj)
(end-obj ,end-obj)
;; (beg-limit ,beg-limit) ; it happens that no function uses it right now.
(end-limit ,end-limit))
,@body))
(defmacro crdt--split-maybe ()
"Split the block if current insertion lies in some CRDT ID block.
Must be used inside CRDT--WITH-INSERTION-INFORMATION."
'(when (and not-end (eq starting-id (crdt--get-starting-id end end-obj)))
;; need to split id block
(crdt--set-id end (crdt--id-replace-offset starting-id (1+ left-offset))
(crdt--end-of-block-p left-pos beg-obj) end-obj end-limit)
(rplacd (get-text-property left-pos 'crdt-id beg-obj) nil) ;; clear end-of-block flag
t))
;;; Buffer local variables
(defmacro crdt--defvar-permanent-local (name &optional initial-value docstring)
"Define a permanent local variable with NAME with INITIAL-VALUE and DOCSTRING."
(declare (indent 2) (doc-string 3) (debug defvar-local))
`(progn
(defvar-local ,name ,initial-value ,docstring)
(put ',name 'permanent-local t)))
(crdt--defvar-permanent-local crdt--session)
(defsubst crdt--assimilate-session (buffer)
"Set CRDT--SESSION of BUFFER to be the same as current CRDT--SESSION."
(let ((session crdt--session))
(with-current-buffer buffer
(setq crdt--session session))))
(cl-defstruct (crdt--contact-metadata (:constructor crdt--make-contact-metadata))
name host service focus)
(cl-defstruct (crdt-remote-fcap
(:constructor crdt--make-remote-fcap
(name nonce in-states out-states interactive-form)))
name nonce in-states out-states interactive-form)
(cl-defstruct (crdt-local-fcap
(:constructor crdt--make-local-fcap
(name nonce in-states out-states proxy)))
name nonce in-states out-states proxy)
(cl-defstruct (crdt--session (:constructor crdt--make-session-1))
local-id ; Local user-id
local-clock ; Local logical clock
(contact-table (make-hash-table))
;; A hash table that maps USER-ID to CRDT--CONTACT-METADATAs
;; Special case: key nil may be mapped to a metadata for a client
;; itself before it gets its user-id. It should be remapped to
;; the right key as soon as client knows its user-id
urlstr
roger-p ;; set to t when network filter hear any data
;; to indicate that TLS handshake (if any) must have completed
user-menu-buffer
buffer-menu-buffer
network-process
network-clients
next-user-id
(buffer-table (make-hash-table :test 'equal)) ; maps buffer network name to buffer
follow-user-id
my-location-marker ; used to store my location temporarily when crdt-goto-{next,prev}-user
permissions
(local-fcap-table (make-hash-table))
(remote-fcap-table (make-hash-table)))
(cl-defun crdt--make-session (&rest args &key local-name host service &allow-other-keys)
(let ((args-1 (cl-copy-list args)))
(cl-remf args-1 :local-name)
(cl-remf args-1 :host)
(cl-remf args-1 :service)
(let ((session (apply #'crdt--make-session-1 args-1)))
(puthash (crdt--session-local-id session)
(crdt--make-contact-metadata :name local-name :host host :service service)
(crdt--session-contact-table session))
session)))
(defvar crdt--inhibit-update nil "When set, don't call CRDT--LOCAL-* on change.
This is useful for functions that apply remote change to local buffer,
to avoid recusive calling of CRDT synchronization functions.")
(crdt--defvar-permanent-local crdt--changed-string nil
"Save changed substring in CRDT--BEFORE-CHANGE.")
(crdt--defvar-permanent-local crdt--changed-start nil
"Save start character address of changes in CRDT--BEFORE-CHANGE,
to recover the portion being overwritten in CRDT--AFTER-CHANGE.")
(crdt--defvar-permanent-local crdt--last-point nil)
(crdt--defvar-permanent-local crdt--last-mark nil)
(crdt--defvar-permanent-local crdt--last-process-mark-id nil)
(crdt--defvar-permanent-local crdt--pseudo-cursor-table nil
"A hash table that maps USER-ID to CONSes.
Each element is of the form (CURSOR-OVERLAY . REGION-OVERLAY).")
(crdt--defvar-permanent-local crdt--site-id-table nil
"A hash table that maps USER-ID to SITE-ID. Only used by the publisher of the buffer.")
(crdt--defvar-permanent-local crdt--site-id-list nil
"A list of all allocated SITE-ID (except 0 which is reserved for publisher), sorted by value.")
(crdt--defvar-permanent-local crdt--site-id-use-list nil
"A list of all allocated SITE-ID (except 0 which is reserved for publisher), sorted by recent usage.")
(crdt--defvar-permanent-local crdt--site-id nil "My SITE-ID at this buffer.")
(cl-defstruct (crdt--overlay-metadata
(:constructor crdt--make-overlay-metadata
(lamport-timestamp species front-advance rear-advance plist))
(:copier crdt--copy-overlay-metadata))
lamport-timestamp species front-advance rear-advance plist)
(crdt--defvar-permanent-local crdt--overlay-table nil
"A hash table that maps CONSes of the form (USER-ID . LOGICAL-CLOCK) to overlays.")
(crdt--defvar-permanent-local crdt--buffer-network-name)
(crdt--defvar-permanent-local crdt--buffer-sync-callback)
(crdt--defvar-permanent-local crdt--buffer-pseudo-process)
(defvar crdt--track-overlay-species nil
"Label any newly created overlay with its value as their ``species''.
You usually want to dynamically bound this variable,
so that overlays created during a dynamic extent
are categorized into the same ``species''.
You can then enable synchronizing those overlays using
function CRDT--ENABLE-OVERLAY-SPECIES.")
(defvar-local crdt--enabled-overlay-species nil
"A list of ``species'' of overlays that are tracked and synchronized.
See CRDT--TRACK-OVERLAY-SPECIES.
You should always use CRDT--ENABLE-OVERLAY-SPECIES
and CRDT--DISABLE-OVERLAY-SPECIES to modify this variable
as those functions handle bookkeeping of
adding/removing actively tracked overlays.")
(defvar-local crdt--enabled-text-properties '(crdt-author)
"A list of text properties that are tracked and synchronized.")
;;; Global variables
(defvar crdt--session-list nil)
(defvar crdt--session-menu-buffer nil)
(defvar crdt--process nil
"Temporarily bound to the current network process when processing messages inside CRDT--NETWORK-FILTER.")
(defvar crdt--remote-call-spawn-user-id nil
"The User ID where current remote call (if any) is orignally called.")
(defvar crdt--return-message-table (make-hash-table))
(defsubst crdt--client-id ()
(process-get crdt--process 'client-id))
;;; crdt-mode
(defvar crdt--hooks-alist
'((after-change-functions . crdt--after-change)
(before-change-functions . crdt--before-change)
(post-command-hook . crdt--post-command)
(deactivate-mark-hook . crdt--post-command)
(kill-buffer-hook . crdt--kill-buffer-hook)
(clone-buffer-hook . crdt--clone-buffer-hook)
(clone-indirect-buffer-hook . crdt--clone-buffer-hook)))
(defun crdt--install-hooks ()
"Install the hooks used by CRDT-MODE."
(dolist (pair crdt--hooks-alist)
(add-hook (car pair) (cdr pair) nil t)))
(defun crdt--uninstall-hooks ()
"Uninstall the hooks used by CRDT-MODE."
(dolist (pair crdt--hooks-alist)
(remove-hook (car pair) (cdr pair) t)))
(defsubst crdt--clear-pseudo-cursor-table ()
"Remove all overlays in CRDT--PSEUDO-CURSOR-TABLE.
Also set CRDT--PSEUDO-CURSOR-TABLE to NIL."
(when crdt--pseudo-cursor-table
(maphash (lambda (_ pair)
(delete-overlay (car pair))
(delete-overlay (cdr pair)))
crdt--pseudo-cursor-table)
(setq crdt--pseudo-cursor-table nil)))
(defun crdt--after-change-major-mode ()
"Re-enable CRDT-MODE after major mode change."
(when (and crdt--session crdt--buffer-network-name
(eq (current-buffer)
(gethash crdt--buffer-network-name
(crdt--session-buffer-table crdt--session))))
(crdt--broadcast-maybe
(crdt--format-message `(ready ,crdt--buffer-network-name ,major-mode)) nil)
(crdt-mode)))
(add-hook 'after-change-major-mode-hook #'crdt--after-change-major-mode)
(define-minor-mode crdt-mode
"Mode for source collaborative buffers."
:lighter " CRDT"
(if crdt-mode
(progn
(unless crdt--pseudo-cursor-table
(setq crdt--pseudo-cursor-table (make-hash-table)))
(unless crdt--overlay-table
(setq crdt--overlay-table (make-hash-table :test 'equal)))
(setq crdt--site-id-list (list 0 crdt--max-value))
(crdt--install-hooks))
(crdt--uninstall-hooks)
(crdt--clear-pseudo-cursor-table)
(setq crdt--overlay-table nil crdt--site-id-list nil
crdt--buffer-network-name nil)))
(defun crdt--clone-buffer-hook ()
(crdt-mode -1))
(defvar crdt-mode-map
(let ((map (make-sparse-keymap)))
(define-key map (kbd "M-X") #'crdt-M-x)
map))
(or (assq 'crdt-mode minor-mode-map-alist)
(nconc minor-mode-map-alist
(list (cons 'crdt-mode crdt-mode-map))))
;;; Author visualization
(defsubst crdt--visualize-author-1 (beg end user-id)
(remove-overlays beg end 'category 'crdt-visualize-author)
(cl-flet ((ov-alike-p (ov)
(and (eq (overlay-get ov 'category) 'crdt-visualize-author)
(eq (overlay-get ov 'crdt-author) user-id))))
(or
(let ((ov-front (cl-find-if #'ov-alike-p (overlays-at (1- beg)))))
(when ov-front (move-overlay ov-front (overlay-start ov-front) end) t))
(let ((ov-rear (cl-find-if #'ov-alike-p (overlays-at end))))
(when ov-rear (move-overlay ov-rear beg (overlay-end ov-rear)) t))
(let ((new-ov (make-overlay beg end nil t nil)))
(overlay-put new-ov 'category 'crdt-visualize-author)
(overlay-put new-ov 'crdt-author user-id)
(overlay-put new-ov 'face `(:background ,(crdt--get-region-color user-id)))))))
(defun crdt--visualize-author ()
(save-restriction
(widen)
(let ((pos (point-max)))
(while (> pos (point-min))
(let* ((prev-pos (previous-single-property-change pos 'crdt-author nil (point-min)))
(user-id (get-text-property prev-pos 'crdt-author)))
(when user-id (crdt--visualize-author-1 prev-pos pos user-id))
(setq pos prev-pos))))))
(define-minor-mode crdt-visualize-author-mode
"Minor mode to visualize who wrote what."
:lighter " CRDT-VAuthor"
(if crdt-visualize-author-mode
(crdt--visualize-author)
(save-restriction
(widen)
(remove-overlays (point-min) (point-max) 'category 'crdt-visualize-author))))
;;; Session state utils
(defsubst crdt--server-p (&optional session)
"Tell if SESSION is running as a server.
If SESSION is nil, use current CRDT--SESSION."
(unless session (setq session crdt--session))
(process-contact (crdt--session-network-process session) :server))
(defsubst crdt--session-local-name (session)
(crdt--contact-metadata-name
(gethash (crdt--session-local-id session) (crdt--session-contact-table session))))
(defmacro crdt--session-focused-buffer-name (session)
`(crdt--contact-metadata-focus
(gethash (crdt--session-local-id ,session) (crdt--session-contact-table ,session))))
;;; Error recovery
(define-error 'crdt-sync-error "CRDT synchronization error")
(defmacro crdt--with-recover (&rest body)
"When any error in BODY occur, signal a CRDT-SYNC-ERROR instead.
This will hopefully trigger error recovery mechanism when further unwinding the stack."
(declare (indent 1) (debug (sexp def-body)))
`(if crdt--inhibit-recover
(progn ,@body)
(condition-case nil
(progn ,@ body)
(error (signal 'crdt-sync-error nil)))))
(defmacro crdt--with-should-not-error (name &rest body)
"When any error in BODY occur, print a report and stop CRDT in this buffer.
NAME is included in the report."
(declare (indent 1) (debug (sexp def-body)))
`(if crdt--inhibit-recover
(progn ,@body)
(condition-case err
(progn ,@ body)
(error
(warn "CRDT mode exited in buffer %s because of error %s inside %s."
(current-buffer) err ',name)
(if (crdt--server-p)
(crdt-stop-share-buffer)
(remhash crdt--buffer-network-name (crdt--session-buffer-table crdt--session))
(crdt--refresh-buffers-maybe)
(crdt-mode -1))))))
(defun crdt--recover (&optional err)
"Try to recover from a synchronization failure.
Current buffer is assmuned to be the one with synchronization error.
If we are the server, ERR is the error we shall report to client."
(if (crdt--server-p)
(progn
(let ((message (crdt--format-message `(error ,crdt--buffer-network-name ,(car err) ,(crdt--readable-encode (cdr err))))))
(process-send-string crdt--process message)))
(ding)
(read-only-mode)
(message "Synchronization error detected, try recovering...")
(crdt--broadcast-maybe
(crdt--format-message `(get ,crdt--buffer-network-name)))))
;;; Shared buffer utils
(defun crdt--call-with-buffer-name (name function)
"Find CRDT shared buffer associated with NAME and call FUNCTION in it.
See `crdt--with-buffer-name'."
(let (crdt-buffer)
(setq crdt-buffer (gethash name (crdt--session-buffer-table crdt--session)))
(when (and crdt-buffer (buffer-live-p crdt-buffer))
(with-current-buffer crdt-buffer
(save-restriction
(widen)
(condition-case err
(funcall function)
(crdt-sync-error (crdt--recover err))))))))
(defmacro crdt--with-buffer-name (name &rest body)
"Find CRDT shared buffer associated with NAME and evaluate BODY in it.
Any narrowing is temporarily disabled during evaluation of BODY.
Also, try to recover from synchronization error if any error happens in BODY.
Must be called when CURRENT-BUFFER is a CRDT status buffer.
If such buffer doesn't exist yet, do nothing."
(declare (indent 1) (debug (sexp def-body)))
`(crdt--call-with-buffer-name ,name (lambda () ,@body)))
(cl-defmacro crdt--with-buffer-name-pull ((name &key sync) &rest body)
"Find CRDT shared buffer associated with NAME and evaluate BODY in it.
Must be called when CURRENT-BUFFER is a CRDT status buffer.
If such buffer doesn't exist yet, request it from the server,
and store the body in CRDT--BUFFER-SYNC-CALLBACK to evaluate it
after synchronization is completed.
If SYNC is non-nil, block (but allow process filters to run)
until synchronization is completed, otherwise run body asynchronously."
(declare (indent 1) (debug (sexp def-body)))
`(let (crdt-buffer)
(setq crdt-buffer (gethash ,name (crdt--session-buffer-table crdt--session)))
(if (and crdt-buffer (buffer-live-p crdt-buffer))
(with-current-buffer crdt-buffer
,@body)
(unless (crdt--server-p)
(setq crdt-buffer (generate-new-buffer (format "%s<%s>" ,name (crdt--session-urlstr crdt--session))))
(puthash ,name crdt-buffer (crdt--session-buffer-table crdt--session))
(let ((session crdt--session))
(with-current-buffer crdt-buffer
(setq crdt--buffer-network-name ,name)
(setq crdt--session session)
(crdt-mode)
(crdt--broadcast-maybe (crdt--format-message `(get ,,name)))
(let ((crdt--inhibit-update t))
(insert "Synchronizing with server...")
(read-only-mode))
,(if sync
`(let (sync-complete)
(setq crdt--buffer-sync-callback
(lambda () (setq sync-complete t)))
(while (not sync-complete)
(accept-process-output))
,@body)
`(setq crdt--buffer-sync-callback
(lambda ()
,@body)))))))))
;;; Session menu
(defsubst crdt--get-session-names (server)
"Get session names for CRDT sessions (from `crdt--session-list').
If SERVER is non-NIL, return the list of names for server sessions.
Otherwise, return the list of names for client sessions."
(let (session-names)
(dolist (session crdt--session-list)
(when (eq (crdt--server-p session) server)
(push (crdt--session-urlstr session) session-names)))
(nreverse session-names)))
(defsubst crdt--get-session (name)
"Get the CRDT session object with NAME."
(cl-find name crdt--session-list
:test 'equal :key #'crdt--session-urlstr))
(defsubst crdt--completing-read (prompt collection &optional initial-input)
"Like (completing-read PROMPT COLLECTION nil t INITIAL-INPUT).
Do better when there are 0 or 1 candidates."
(if collection
(if (cdr collection)
(completing-read prompt collection nil t initial-input)
(car collection))
(signal 'quit "No candidates")))
(defun crdt--read-session (&optional filter)
"Prompt for a session name and return the corresponding session.
FILTER can be nil, 'server or 'client."
(crdt--get-session
(crdt--completing-read
(format "Choose a%s session: "
(cl-ecase filter
((server) " server")
((client) " client")
((nil) "")))
(cl-ecase filter
((server) (crdt--get-session-names t))
((client) (crdt--get-session-names nil))
((nil) (mapcar #'crdt--session-urlstr crdt--session-list)))
(when (and crdt--session
(cl-ecase filter
((server) (crdt--server-p))
((client) (not (crdt--server-p)))
((nil) t)))
(crdt--session-urlstr crdt--session)))))
(defun crdt--read-session-maybe (&optional filter)
"Prompt for a session name and return the corresponding session.
Directly return the session name under point if in the session menu.
FILTER can be nil, 'server or 'client."
(if (eq major-mode 'crdt-session-menu-mode)
(or (tabulated-list-get-id) (signal 'quit nil))
(if (and crdt--session
(cl-ecase filter
((server) (crdt--server-p))
((client) (not (crdt--server-p)))
((nil) t)))
crdt--session
(or (crdt--read-session filter) (signal 'quit nil)))))
(defvar crdt-session-menu-mode-map
(let ((map (make-sparse-keymap)))
(define-key map (kbd "RET") #'crdt-list-buffers)
(define-key map [mouse-1] #'crdt-list-buffers)
(define-key map (kbd "k") #'crdt--stop-session)
(define-key map (kbd "d") #'crdt--stop-session)
map))
(define-derived-mode crdt-session-menu-mode tabulated-list-mode
"CRDT Session List"
(setq tabulated-list-format [("Session Name" 15 t)
("Role" 7 t)
("My Name" 15 t)
("Buffers" 30 t)
("Users" 15 t)]))
;;;###autoload
(defun crdt-list-sessions (&optional display-buffer)
"Display a list of active CRDT sessions.
If DISPLAY-BUFFER is provided, display the output there."
(interactive)
(unless display-buffer
(unless (and crdt--session-menu-buffer (buffer-live-p crdt--session-menu-buffer))
(setf crdt--session-menu-buffer
(generate-new-buffer "*CRDT Sessions*")))
(setq display-buffer crdt--session-menu-buffer))
(crdt-refresh-sessions display-buffer)
(switch-to-buffer-other-window display-buffer))
(defun crdt-refresh-sessions (display-buffer)
"Refresh the CRDT session menu in DISPLAY-BUFFER."
(with-current-buffer display-buffer
(crdt-session-menu-mode)
(setq tabulated-list-entries nil)
(mapc (lambda (session)
(push
(list session (vector (crdt--session-urlstr session)
(if (crdt--server-p session) "Server" "Client")
(crdt--session-local-name session)
(mapconcat (lambda (v) (format "%s" v))
(hash-table-keys (crdt--session-buffer-table session))
", ")
(mapconcat (lambda (v) (format "%s" v))
(mapcar #'crdt--contact-metadata-name
(hash-table-values (crdt--session-contact-table session)))
", ")))
tabulated-list-entries))
crdt--session-list)
(tabulated-list-init-header)
(tabulated-list-print)))
(defsubst crdt--refresh-sessions-maybe ()
"Refresh the session menu buffer, if there's any."
(when (and crdt--session-menu-buffer (buffer-live-p crdt--session-menu-buffer))
(crdt-refresh-sessions crdt--session-menu-buffer)))
;;; Buffer menu
(defun crdt--read-buffer (session)
"Prompt for a buffer network name in SESSION."
(crdt--completing-read
"Choose a buffer: "
(hash-table-keys (crdt--session-buffer-table session))
(when (and (eq crdt--session session)
crdt--buffer-network-name)
crdt--buffer-network-name)))
(defun crdt--read-buffer-maybe (session)
"Prompt for a buffer network name in SESSION.
Directly return the buffer network name under point if in the buffer menu."
(or (and (eq crdt--session session)
(if (eq major-mode 'crdt-buffer-menu-mode)
(or (tabulated-list-get-id) (signal 'quit nil))
crdt--buffer-network-name))
(crdt--read-buffer session)
(signal 'quit nil)))
(defun crdt--do-to-buffer (session network-name f)
"Apply F to buffer with SESSION and NETWORK-NAME."
(let ((crdt--session session))
(crdt--with-buffer-name-pull (network-name)
(funcall f (current-buffer)))))
(defun crdt-switch-to-buffer-other-window (session network-name)
"From the buffer list menu, open buffer with NETWORK-NAME in SESSION."
(interactive
(let ((session (crdt--read-session-maybe)))
(list session (crdt--read-buffer-maybe session))))
(crdt--do-to-buffer session network-name #'switch-to-buffer-other-window))
(defun crdt-switch-to-buffer (session network-name)
"Switch to buffer with NETWORK-NAME in SESSION."
(interactive
(let* ((session (crdt--read-session-maybe))
(buffers (hash-table-keys (crdt--session-buffer-table session))))
(list session (completing-read "Choose a buffer: " buffers nil t))))
(crdt--do-to-buffer session network-name #'switch-to-buffer))
(defvar crdt-buffer-menu-mode-map
(let ((map (make-sparse-keymap)))
(define-key map (kbd "RET") #'crdt-switch-to-buffer-other-window)
(define-key map [mouse-1] #'crdt-switch-to-buffer-other-window)
(define-key map (kbd "k") #'crdt-stop-share-buffer)
(define-key map (kbd "d") #'crdt-stop-share-buffer)
map))
(define-derived-mode crdt-buffer-menu-mode tabulated-list-mode
"CRDT Buffer List"
(setq tabulated-list-format [("Local Buffer" 15 t)
("Network Name" 30 t)
("Users" 15 t)]))
;;;###autoload
(defun crdt-list-buffers (&optional session)
"Display a list of buffers shared in SESSION."
(interactive (list (crdt--read-session-maybe)))
(let ((crdt--session (or session crdt--session)))
(with-current-buffer (current-buffer)
(unless crdt--session
(error "Not a CRDT shared buffer"))
(unless (and (crdt--session-buffer-menu-buffer crdt--session) (buffer-live-p (crdt--session-buffer-menu-buffer crdt--session)))
(setf (crdt--session-buffer-menu-buffer crdt--session)
(generate-new-buffer (format "*CRDT Buffers %s*" (crdt--session-urlstr crdt--session))))
(crdt--assimilate-session (crdt--session-buffer-menu-buffer crdt--session)))
(let ((display-buffer (crdt--session-buffer-menu-buffer crdt--session)))
(crdt-refresh-buffers display-buffer)
(if (crdt--session-network-process crdt--session)
(switch-to-buffer display-buffer)
(switch-to-buffer-other-window display-buffer))))))
(defun crdt-refresh-buffers (display-buffer)
"Refresh the CRDT buffer menu in DISPLAY-BUFFER."
(with-current-buffer display-buffer
(crdt-buffer-menu-mode)
(setq tabulated-list-entries nil)
(let ((tmp-hashtable (make-hash-table :test 'equal)))
(maphash (lambda (_ v)
(push (crdt--contact-metadata-name v)
(gethash (crdt--contact-metadata-focus v)
tmp-hashtable)))
(crdt--session-contact-table crdt--session))
(maphash (lambda (k v)
(push (list k (vector (if (and v (buffer-live-p v))
(buffer-name v)
"--")
k (mapconcat #'identity (gethash k tmp-hashtable) ", ")))
tabulated-list-entries))
(crdt--session-buffer-table crdt--session)))
(tabulated-list-init-header)
(tabulated-list-print)))
(defsubst crdt--refresh-buffers-maybe ()
"Refresh the buffer menu buffer for current session, if there's any."
(when (and (crdt--session-buffer-menu-buffer crdt--session) (buffer-live-p (crdt--session-buffer-menu-buffer crdt--session)))
(crdt-refresh-buffers (crdt--session-buffer-menu-buffer crdt--session)))
(crdt--refresh-sessions-maybe))
;;; User menu
(defun crdt--read-user (session)
"Prompt for a user name in SESSION."
(let (candidates)
(maphash
(lambda (k v)
(push (format "%s %s" k (crdt--contact-metadata-name v)) candidates))
(crdt--session-contact-table session))
(let ((name
(crdt--completing-read "Choose a user: " candidates)))
(string-to-number (car (split-string name))))))
(defun crdt--read-user-maybe (session)
"Prompt for a user name in SESSION.
Directly return the user name under point if in the user menu."
(or (and (eq crdt--session session)
(eq major-mode 'crdt-user-menu-mode)
(or (tabulated-list-get-id) (signal 'quit nil)))
(crdt--read-user session)
(signal 'quit nil)))
(defun crdt-goto-user (session user-id)
"Goto the cursor location of user with USER-ID in SESSION."
(interactive (let ((session (crdt--read-session-maybe)))
(list session (crdt--read-user-maybe session))))
(let ((crdt--session session)
(switch-window-function
(if (eq major-mode 'crdt-user-menu-mode) #'switch-to-buffer-other-window #'switch-to-buffer)))
(if (eq user-id (crdt--session-local-id crdt--session))
(funcall switch-window-function
(gethash (crdt--session-focused-buffer-name crdt--session) (crdt--session-buffer-table crdt--session)))
(unless
(cl-block nil
(let* ((metadata (or (gethash user-id (crdt--session-contact-table crdt--session)) (cl-return)))
(buffer-name (or (crdt--contact-metadata-focus metadata) (cl-return))))
(crdt--with-buffer-name-pull (buffer-name)
(funcall switch-window-function (current-buffer))
(ignore-errors (goto-char (overlay-start (car (gethash user-id crdt--pseudo-cursor-table)))))
t)))
(message "Doesn't have position information for this user yet.")))))
(defun crdt--session-ensure-user-menu-buffer (session)
(unless (and (crdt--session-user-menu-buffer session)
(buffer-live-p (crdt--session-user-menu-buffer session)))
(setf (crdt--session-user-menu-buffer session)
(generate-new-buffer (format "*CRDT Users %s*" (crdt--session-urlstr session))))
(crdt--assimilate-session (crdt--session-user-menu-buffer session))))
(defun crdt--cycle-user (&optional prev)
"Move point in user menu buffer and goto its cursor position.
If user menu buffer does not exist yet, create it.
If PREV is non-nil, move backward, otherwise move forward.
When moving into/out of ourselves, push/pop a global marker instead."
(unless crdt--session
(error "Not a CRDT shared buffer"))
(crdt--session-ensure-user-menu-buffer crdt--session)
(let* ((mark (point-marker))
(user-id
(with-current-buffer (crdt--session-user-menu-buffer crdt--session)
(when (= (point) (point-max))
(forward-line -1))
(when (eq (tabulated-list-get-id) (crdt--session-local-id crdt--session))
(setf (crdt--session-my-location-marker crdt--session) mark)
(add-to-history 'global-mark-ring mark global-mark-ring-max t))
(if prev
(unless (= (forward-line -1) 0)
(goto-char (point-max))
(forward-line -1))
(forward-line)
(when (= (point) (point-max))
(goto-char (point-min))))
(let ((window (get-buffer-window (current-buffer) t)))
(when window (set-window-point window (point))))
(if (eq (tabulated-list-get-id) (crdt--session-local-id crdt--session))
(when (crdt--session-my-location-marker crdt--session)
(if (eq (car global-mark-ring) (crdt--session-my-location-marker crdt--session))
(pop-global-mark)
(goto-char (crdt--session-my-location-marker crdt--session)))
nil)
(tabulated-list-get-id)))))
(when user-id (crdt-goto-user crdt--session user-id))))
(defun crdt-goto-next-user ()