view contrib/mq.el @ 39687:bfeab472e3c0

localrepo: create new function for instantiating a local repo object

Today, there is a single local repository class - localrepository. Its
__init__ is responsible for loading the .hg/requires file and taking
different actions depending on what is present.

In addition, extensions may define a "reposetup" function that
monkeypatches constructed repository instances, often by implementing
a derived type and changing the __class__ of the repo instance.

Work around alternate storage backends and partial clone has made it
clear to me that shoehorning all this logic into __init__ and operating
on an existing instance is too convoluted. For example, localrepository
assumes revlog storage and swapping in non-revlog storage requires
overriding e.g. file() to return something that isn't a revlog. I've
authored various patches that either:

a) teach various methods (like file()) about different states and
   taking the appropriate code path at run-time
b) create methods/attributes/callables used for instantiating things
   and populating these in __init__

"a" incurs run-time performance penalties and makes code more
complicated since various functions have a bunch of "if storage is X"
branches.

"b" makes localrepository quickly explode in complexity.

My plan for tackling this problem is to make the local repository type
more dynamic. Instead of a static localrepository class/type that
supports all of the local repository configurations (revlogs vs other,
revlogs with ellipsis, revlog v1 versus revlog v2, etc), we'll
dynamically construct a type providing the implementations that are
needed for the repository on disk, derived from the .hg/requires file
and configuration options. The constructed repository type will be
specialized and methods won't need to be taught about different
implementations nor overloaded.

We may also leverage this functionality for building types that don't
implement all attributes. For example, the "intents" feature allows
commands to declare that they are read only. By dynamically
constructing a repository type, we could return a repository instance
with no attributes related to mutating the repository. This could
include things like a "changelog" property implementation that doesn't
check whether it needs to invalidate the hidden revisions set on every
access.

This commit establishes a function for building a local repository
instance. Future commits will start moving functionality from
localrepository.__init__ to this function. Then we'll start dynamically
changing the returned type depending on options that are present.

This change may seem radical. But it should be fully compatible with
the reposetup() model - at least for now.

Differential Revision: https://phab.mercurial-scm.org/D4563

;;; mq.el --- Emacs support for Mercurial Queues

;; Copyright (C) 2006 Bryan O'Sullivan

;; Author: Bryan O'Sullivan <[e-mail]>

;; mq.el is free software; you can redistribute it and/or modify it
;; under the terms of the GNU General Public License version 2 or any
;; later version.

;; mq.el 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 mq.el, GNU Emacs, or XEmacs; see the file COPYING (`C-h
;; C-l').  If not, see <http://www.gnu.org/licenses/>.

(eval-when-compile (require 'cl))
(require 'mercurial)


(defcustom mq-mode-hook nil
  "Hook run when a buffer enters mq-mode."
  :type 'sexp
  :group 'mercurial)

(defcustom mq-global-prefix "\C-cq"
  "The global prefix for Mercurial Queues keymap bindings."
  :type 'sexp
  :group 'mercurial)

(defcustom mq-edit-mode-hook nil
  "Hook run after a buffer is populated to edit a patch description."
  :type 'sexp
  :group 'mercurial)

(defcustom mq-edit-finish-hook nil
  "Hook run before a patch description is finished up with."
  :type 'sexp
  :group 'mercurial)

(defcustom mq-signoff-address nil
  "Address with which to sign off on a patch."
  :type 'string
  :group 'mercurial)


;;; Internal variables.

(defvar mq-mode nil
  "Is this file managed by MQ?")
(make-variable-buffer-local 'mq-mode)
(put 'mq-mode 'permanent-local t)

(defvar mq-patch-history nil)

(defvar mq-top-patch '(nil))

(defvar mq-prev-buffer nil)
(make-variable-buffer-local 'mq-prev-buffer)
(put 'mq-prev-buffer 'permanent-local t)

(defvar mq-top nil)
(make-variable-buffer-local 'mq-top)
(put 'mq-top 'permanent-local t)

;;; Global keymap.

(defvar mq-global-map
  (let ((map (make-sparse-keymap)))
    (define-key map "." 'mq-push)
    (define-key map ">" 'mq-push-all)
    (define-key map "," 'mq-pop)
    (define-key map "<" 'mq-pop-all)
    (define-key map "=" 'mq-diff)
    (define-key map "r" 'mq-refresh)
    (define-key map "e" 'mq-refresh-edit)
    (define-key map "i" 'mq-new)
    (define-key map "n" 'mq-next)
    (define-key map "o" 'mq-signoff)
    (define-key map "p" 'mq-previous)
    (define-key map "s" 'mq-edit-series)
    (define-key map "t" 'mq-top)
    map))

(global-set-key mq-global-prefix mq-global-map)

(add-minor-mode 'mq-mode 'mq-mode)


;;; Refresh edit mode keymap.

(defvar mq-edit-mode-map
  (let ((map (make-sparse-keymap)))
    (define-key map "\C-c\C-c" 'mq-edit-finish)
    (define-key map "\C-c\C-k" 'mq-edit-kill)
    (define-key map "\C-c\C-s" 'mq-signoff)
    map))


;;; Helper functions.

(defun mq-read-patch-name (&optional source prompt force)
  "Read a patch name to use with a command.
May return nil, meaning \"use the default\"."
  (let ((patches (split-string
		  (hg-chomp (hg-run0 (or source "qseries"))) "\n")))
    (when force
      (completing-read (format "Patch%s: " (or prompt ""))
		       (mapcar (lambda (x) (cons x x)) patches)
		       nil
		       nil
		       nil
		       'mq-patch-history))))

(defun mq-refresh-buffers (root)
  (save-excursion
    (dolist (buf (hg-buffers-visiting-repo root))
      (when (not (verify-visited-file-modtime buf))
	(set-buffer buf)
	(let ((ctx (hg-buffer-context)))
	  (message "Refreshing %s..." (buffer-name))
	  (revert-buffer t t t)
	  (hg-restore-context ctx)
	  (message "Refreshing %s...done" (buffer-name))))))
  (hg-update-mode-lines root)
  (mq-update-mode-lines root))

(defun mq-last-line ()
  (goto-char (point-max))
  (beginning-of-line)
  (when (looking-at "^$")
    (forward-line -1))
  (let ((bol (point)))
    (end-of-line)
    (let ((line (buffer-substring bol (point))))
      (when (> (length line) 0)
	line))))

(defun mq-push (&optional patch)
  "Push patches until PATCH is reached.
If PATCH is nil, push at most one patch."
  (interactive (list (mq-read-patch-name "qunapplied" " to push"
					 current-prefix-arg)))
  (let ((root (hg-root))
	(prev-buf (current-buffer))
	last-line ok)
    (unless root
      (error "Cannot push outside a repository!"))
    (hg-sync-buffers root)
    (let ((buf-name (format "MQ: Push %s" (or patch "next patch"))))
      (kill-buffer (get-buffer-create buf-name))
      (split-window-vertically)
      (other-window 1)
      (switch-to-buffer (get-buffer-create buf-name))
      (cd root)
      (message "Pushing...")
      (setq ok (= 0 (apply 'call-process (hg-binary) nil t t "qpush"
			   (if patch (list patch))))
	    last-line (mq-last-line))
      (let ((lines (count-lines (point-min) (point-max))))
	(if (or (<= lines 1)
		(and (equal lines 2) (string-match "Now at:" last-line)))
	    (progn
	      (kill-buffer (current-buffer))
	      (delete-window))
	  (hg-view-mode prev-buf))))
    (mq-refresh-buffers root)
    (sit-for 0)
    (when last-line
      (if ok
	  (message "Pushing... %s" last-line)
	(error "Pushing... %s" last-line)))))

(defun mq-push-all ()
  "Push patches until all are applied."
  (interactive)
  (mq-push "-a"))

(defun mq-pop (&optional patch)
  "Pop patches until PATCH is reached.
If PATCH is nil, pop at most one patch."
  (interactive (list (mq-read-patch-name "qapplied" " to pop to"
					 current-prefix-arg)))
  (let ((root (hg-root))
	last-line ok)
    (unless root
      (error "Cannot pop outside a repository!"))
    (hg-sync-buffers root)
    (set-buffer (generate-new-buffer "qpop"))
    (cd root)
    (message "Popping...")
    (setq ok (= 0 (apply 'call-process (hg-binary) nil t t "qpop"
			 (if patch (list patch))))
	  last-line (mq-last-line))
    (kill-buffer (current-buffer))
    (mq-refresh-buffers root)
    (sit-for 0)
    (when last-line
      (if ok
	  (message "Popping... %s" last-line)
	(error "Popping... %s" last-line)))))

(defun mq-pop-all ()
  "Push patches until none are applied."
  (interactive)
  (mq-pop "-a"))

(defun mq-refresh-internal (root &rest args)
  (hg-sync-buffers root)
  (let ((patch (mq-patch-info "qtop")))
    (message "Refreshing %s..." patch)
    (let ((ret (apply 'hg-run "qrefresh" args)))
      (if (equal (car ret) 0)
	  (message "Refreshing %s... done." patch)
	(error "Refreshing %s... %s" patch (hg-chomp (cdr ret)))))))

(defun mq-refresh (&optional git)
  "Refresh the topmost applied patch.
With a prefix argument, generate a git-compatible patch."
  (interactive "P")
  (let ((root (hg-root)))
    (unless root
      (error "Cannot refresh outside of a repository!"))
    (apply 'mq-refresh-internal root (if git '("--git")))))

(defun mq-patch-info (cmd &optional msg)
  (let* ((ret (hg-run cmd))
	 (info (hg-chomp (cdr ret))))
    (if (equal (car ret) 0)
	(if msg
	    (message "%s patch: %s" msg info)
	  info)
      (error "%s" info))))

(defun mq-top ()
  "Print the name of the topmost applied patch."
  (interactive)
  (mq-patch-info "qtop" "Top"))

(defun mq-next ()
  "Print the name of the next patch to be pushed."
  (interactive)
  (mq-patch-info "qnext" "Next"))

(defun mq-previous ()
  "Print the name of the first patch below the topmost applied patch.
This would become the active patch if popped to."
  (interactive)
  (mq-patch-info "qprev" "Previous"))

(defun mq-edit-finish ()
  "Finish editing the description of this patch, and refresh the patch."
  (interactive)
  (unless (equal (mq-patch-info "qtop") mq-top)
    (error "Topmost patch has changed!"))
  (hg-sync-buffers hg-root)
  (run-hooks 'mq-edit-finish-hook)
  (mq-refresh-internal hg-root "-m" (buffer-substring (point-min) (point-max)))
  (let ((buf mq-prev-buffer))
    (kill-buffer nil)
    (switch-to-buffer buf)))

(defun mq-edit-kill ()
  "Kill the edit currently being prepared."
  (interactive)
  (when (or (not (buffer-modified-p)) (y-or-n-p "Really kill this edit? "))
    (let ((buf mq-prev-buffer))
      (kill-buffer nil)
      (switch-to-buffer buf))))

(defun mq-get-top (root)
  (let ((entry (assoc root mq-top-patch)))
    (if entry
        (cdr entry))))

(defun mq-set-top (root patch)
  (let ((entry (assoc root mq-top-patch)))
    (if entry
        (if patch
            (setcdr entry patch)
          (setq mq-top-patch (delq entry mq-top-patch)))
      (setq mq-top-patch (cons (cons root patch) mq-top-patch)))))

(defun mq-update-mode-lines (root)
  (let ((cwd default-directory))
    (cd root)
    (condition-case nil
        (mq-set-top root (mq-patch-info "qtop"))
      (error (mq-set-top root nil)))
    (cd cwd))
  (let ((patch (mq-get-top root)))
    (save-excursion
      (dolist (buf (hg-buffers-visiting-repo root))
        (set-buffer buf)
        (if mq-mode
            (setq mq-mode (or (and patch (concat " MQ:" patch)) " MQ")))))))
	
(defun mq-mode (&optional arg)
  "Minor mode for Mercurial repositories with an MQ patch queue"
  (interactive "i")
  (cond ((hg-root)
         (setq mq-mode (if (null arg) (not mq-mode)
                         arg))
         (mq-update-mode-lines (hg-root))))
  (run-hooks 'mq-mode-hook))

(defun mq-edit-mode ()
  "Mode for editing the description of a patch.

Key bindings
------------
\\[mq-edit-finish]	use this description
\\[mq-edit-kill]	abandon this description"
  (interactive)
  (use-local-map mq-edit-mode-map)
  (set-syntax-table text-mode-syntax-table)
  (setq local-abbrev-table text-mode-abbrev-table
	major-mode 'mq-edit-mode
	mode-name "MQ-Edit")
  (set-buffer-modified-p nil)
  (setq buffer-undo-list nil)
  (run-hooks 'text-mode-hook 'mq-edit-mode-hook))

(defun mq-refresh-edit ()
  "Refresh the topmost applied patch, editing the patch description."
  (interactive)
  (while mq-prev-buffer
    (set-buffer mq-prev-buffer))
  (let ((root (hg-root))
	(prev-buffer (current-buffer))
	(patch (mq-patch-info "qtop")))
    (hg-sync-buffers root)
    (let ((buf-name (format "*MQ: Edit description of %s*" patch)))
      (switch-to-buffer (get-buffer-create buf-name))
      (when (= (point-min) (point-max))
	(set (make-local-variable 'hg-root) root)
	(set (make-local-variable 'mq-top) patch)
	(setq mq-prev-buffer prev-buffer)
	(insert (hg-run0 "qheader"))
	(goto-char (point-min)))
      (mq-edit-mode)
      (cd root)))
  (message "Type `C-c C-c' to finish editing and refresh the patch."))

(defun mq-new (name)
  "Create a new empty patch named NAME.
The patch is applied on top of the current topmost patch.
With a prefix argument, forcibly create the patch even if the working
directory is modified."
  (interactive (list (mq-read-patch-name "qseries" " to create" t)))
  (message "Creating patch...")
  (let ((ret (if current-prefix-arg
		 (hg-run "qnew" "-f" name)
	       (hg-run "qnew" name))))
    (if (equal (car ret) 0)
	(progn
	  (hg-update-mode-lines (buffer-file-name))
	  (message "Creating patch... done."))
      (error "Creating patch... %s" (hg-chomp (cdr ret))))))

(defun mq-edit-series ()
  "Edit the MQ series file directly."
  (interactive)
  (let ((root (hg-root)))
    (unless root
      (error "Not in an MQ repository!"))
    (find-file (concat root ".hg/patches/series"))))

(defun mq-diff (&optional git)
  "Display a diff of the topmost applied patch.
With a prefix argument, display a git-compatible diff."
  (interactive "P")
  (hg-view-output ((format "MQ: Diff of %s" (mq-patch-info "qtop")))
    (if git
	(call-process (hg-binary) nil t nil "qdiff" "--git")
    (call-process (hg-binary) nil t nil "qdiff"))
    (diff-mode)
    (font-lock-fontify-buffer)))

(defun mq-signoff ()
  "Sign off on the current patch, in the style used by the Linux kernel.
If the variable mq-signoff-address is non-nil, it will be used, otherwise
the value of the ui.username item from your hgrc will be used."
  (interactive)
  (let ((was-editing (eq major-mode 'mq-edit-mode))
	signed)
    (unless was-editing
      (mq-refresh-edit))
    (save-excursion
      (let* ((user (or mq-signoff-address
		       (hg-run0 "debugconfig" "ui.username")))
	     (signoff (concat "Signed-off-by: " user)))
	(if (search-forward signoff nil t)
	    (message "You have already signed off on this patch.")
	  (goto-char (point-max))
	  (let ((case-fold-search t))
	    (if (re-search-backward "^Signed-off-by: " nil t)
		(forward-line 1)
	      (insert "\n")))
	  (insert signoff)
	  (message "%s" signoff)
	  (setq signed t))))
    (unless was-editing
      (if signed
	  (mq-edit-finish)
	(mq-edit-kill)))))


(provide 'mq)


;;; Local Variables:
;;; prompt-to-byte-compile: nil
;;; end: