[PATCH v3] Emacs: Add address completion mechanism implemented in elisp

[David Edmondson]

On Mon, Aug 11 2014, Michal Sojka wrote:
> Currently, notmuch has an address completion mechanism that requires
> external command to provide completion candidates. This patch adds a
> completion mechanism inspired by https://github.com/tjim/nevermore,
> which is implemented in Emacs lisp only.
>
> The core of the new mechanism is the function notmuch-address-harvest
> that collects the completion candidates from the notmuch database and
> stores them in notmuch-address-completions variable.
> notmuch-address-harvest is called on the first entry to message-mode
> and runs asychnornously so that the user doesn't have to wait for it
> to complete while composing the message. The
> notmuch-address-completions variable is used in message-mode as a
> source of completion candidates. Currently, there are two ways how the
> notmuch-address-completions variable is used.
>
> First, preexisting address completion mechanism is extended to use
> notmuch-address-completions in addition to the external command. This
> new behavior is configured by setting notmuch-address-command to nil,
> which is the new default. Note that this may *BREAK EXISTING SETUPS*
> when the user used external command named "notmuch-addresses", i.e.
> the previous default. The result will be that the user will use the
> new mechanism instead of the his command. I believe that many users
> may not even recognize this because the new mechanism works the same
> as http://commonmeasure.org/~jkr/git/notmuch_addresses.git and perhaps
> also as other commands suggested at
> http://notmuchmail.org/emacstips/#address_completion.
>
> Second way of using notmuch-address-completions is notmuch-company.el.
> This presents the possible completions in a nice popup box after a
> short typing delay but requires company-mode to be installed.

This looks great, thanks for doing it. It seems like a better approach
than id:1409921969-65129-1-git-send-email-dme at dme.org. Some comments:

- Adding the address collection to `message-mode-hook' means that it
  runs every time I start to compose a message. If the address
  collection is disk intensive, this might be bad for battery life. The
  set of potential recipients doesn't change _that_ much over time for a
  typical person, I'd wager. Maybe the hook should only run once a day?
  (Tunable, of course.)

- The addition of company mode support (which I haven't tried) should be
  a separate patch in the series.

> ---
> Changes from v1:
> - Use of notmuch-parser.el instead of the custom parser in the
>   original code. The notmuch parser is slightly faster.
> - Use of functions in notmuch-query.el instead of functions in the
>   original code with almost the same functionality.
> - Integrated with existing completion mechanism in notmuch.
> - notmuch-company.el was moved from emacs/contrib to emacs and
>   no-byte-compile directive was added to it.
> - Aligned with notmuch naming conventions.
> - Documented bugs found in notmuch-company.el
>
> Changes from v2:
> - Updated Makefile.local to not conflict with current master
> ---
>  emacs/Makefile.local     |  6 ++-
>  emacs/notmuch-address.el | 95 +++++++++++++++++++++++++++++++++++++++++++-----
>  emacs/notmuch-company.el | 69 +++++++++++++++++++++++++++++++++++
>  emacs/notmuch-lib.el     |  3 ++
>  4 files changed, 163 insertions(+), 10 deletions(-)
>  create mode 100644 emacs/notmuch-company.el
>
> diff --git a/emacs/Makefile.local b/emacs/Makefile.local
> index 1109cfa..6c93e73 100644
> --- a/emacs/Makefile.local
> +++ b/emacs/Makefile.local
> @@ -20,6 +20,7 @@ emacs_sources := \
>  	$(dir)/notmuch-print.el \
>  	$(dir)/notmuch-version.el \
>  	$(dir)/notmuch-jump.el \
> +	$(dir)/notmuch-company.el
>  
>  $(dir)/notmuch-version.el: $(dir)/Makefile.local version.stamp
>  $(dir)/notmuch-version.el: $(srcdir)/$(dir)/notmuch-version.el.tmpl
> @@ -30,7 +31,10 @@ $(dir)/notmuch-version.el: $(srcdir)/$(dir)/notmuch-version.el.tmpl
>  emacs_images := \
>  	$(srcdir)/$(dir)/notmuch-logo.png
>  
> -emacs_bytecode = $(emacs_sources:.el=.elc)
> +# Do not try to install files that are not byte-compiled.
> +emacs_no_byte_compile := $(dir)/notmuch-company.el
> +
> +emacs_bytecode = $(patsubst %.el,%.elc,$(filter-out $(emacs_no_byte_compile),$(emacs_sources)))
>  
>  # Because of defmacro's and defsubst's, we have to account for load
>  # dependencies between Elisp files when byte compiling.  Otherwise,
> diff --git a/emacs/notmuch-address.el b/emacs/notmuch-address.el
> index fa65cd5..a50f4f4 100644
> --- a/emacs/notmuch-address.el
> +++ b/emacs/notmuch-address.el
> @@ -20,14 +20,18 @@
>  ;; Authors: David Edmondson <dme at dme.org>
>  
>  (require 'message)
> +(require 'notmuch-query)
> +(require 'notmuch-parser)
>  
>  ;;
>  
> -(defcustom notmuch-address-command "notmuch-addresses"
> -  "The command which generates possible addresses. It must take a
> -single argument and output a list of possible matches, one per
> -line."
> -  :type 'string
> +(defcustom notmuch-address-command nil
> +  "The command which generates possible addresses for completion.
> +It must take a single argument and output a list of possible
> +matches, one per line. If set to nil, addresses are generated by
> +a built-in completion mechanism."
> +  :type '(radio (const :tag "No command: Use built-in completion" nil)
> +		 (string :tag "Custom command" :value "notmuch-addresses"))
>    :group 'notmuch-send
>    :group 'notmuch-external)
>  
> @@ -42,6 +46,10 @@ to know how address selection is made by default."
>    :group 'notmuch-send
>    :group 'notmuch-external)
>  
> +(defvar notmuch-address-completions nil
> +  "Hash of email addresses for completion during email composition.
> +  This variable is set by calling `notmuch-address-harvest'.")
> +
>  (defun notmuch-address-selection-function (prompt collection initial-input)
>    "Call (`completing-read'
>        PROMPT COLLECTION nil nil INITIAL-INPUT 'notmuch-address-history)"
> @@ -60,7 +68,16 @@ to know how address selection is made by default."
>  	  (push notmuch-address-message-alist-member message-completion-alist))))
>  
>  (defun notmuch-address-options (original)
> -  (process-lines notmuch-address-command original))
> +  (cond
> +   ((eq notmuch-address-command nil)
> +    (let ((candidates))
> +      (maphash (lambda (key val)
> +		 (let ((re (concat "\\<" (regexp-quote original))))
> +		   (when (string-match re key)
> +		     (push key candidates))))
> +	       notmuch-address-completions)
> +      candidates))
> +   (t (process-lines notmuch-address-command original))))
>  
>  (defun notmuch-address-expand-name ()
>    (let* ((end (point))
> @@ -108,11 +125,71 @@ to know how address selection is made by default."
>  			   (not (file-directory-p bin))))
>  	      (throw 'found-command bin))))))))
>  
> -;; If we can find the program specified by `notmuch-address-command',
> -;; insinuate ourselves into `message-mode'.
> -(when (notmuch-address-locate-command notmuch-address-command)
> +(defun notmuch-address-harvest-msg (msg)
> +  (let* ((headers (plist-get msg :headers))
> +	 (to (ignore-errors (mail-extract-address-components (plist-get headers :To) t)))
> +	 (cc (ignore-errors (mail-extract-address-components (plist-get headers :Cc) t)))
> +	 (bcc (ignore-errors (mail-extract-address-components (plist-get headers :Bcc) t))))
> +    (mapc (lambda (parts)
> +	    (let* ((name (car parts))
> +		   (email (cadr parts))
> +		   (entry (if name (format "%s <%s>" name email) email)))
> +	      (puthash entry t notmuch-address-completions)))
> +	  (append to cc bcc))
> +    nil))
> +
> +(defun notmuch-address-harvest-handle-result (obj)
> +  (notmuch-query-map-threads 'notmuch-address-harvest-msg (list obj)))
> +
> +(defun notmuch-address-harvest-filter (proc string)
> +  (when (buffer-live-p (process-buffer proc))
> +    (with-current-buffer (process-buffer proc)
> +      (save-excursion
> +	(goto-char (point-max))
> +	(insert string))
> +      (notmuch-sexp-parse-partial-list
> +       'notmuch-address-harvest-handle-result (process-buffer proc)))))
> +
> +(defvar notmuch-address-harvest-proc nil)   ; the process of a harvest underway
> +
> +(defun notmuch-address-harvest ()
> +  "Collect possible addresses for completion. It queries the
> +notmuch database for all emails sent by the user and collects the
> +destination addresses from them in
> +`notmuch-address-completions'. This takes some time so the
> +address collection runs asynchronously."
> +  (when notmuch-address-harvest-proc
> +    (kill-buffer (process-buffer notmuch-address-harvest-proc)) ; this also kills the process
> +    (setq notmuch-address-harvest-proc nil))
> +  (setq notmuch-address-completions (make-hash-table :test 'equal))
> +  (setq notmuch-address-harvest-proc
> +        (notmuch-start-notmuch
> +         "notmuch-address-harvest"	; process name
> +         " *notmuch-address-harvest*"	; process buffer
> +         nil				; process sentinel
> +         "show"				; notmuch command
> +         "--format=sexp"
> +         "--format-version=2"
> +         "--body=false"
> +         "--entire-thread=false"
> +	 (mapconcat (lambda (x) (concat "from:" x)) (notmuch-user-emails) " or ")))
> +  (set-process-filter notmuch-address-harvest-proc 'notmuch-address-harvest-filter)
> +  (set-process-query-on-exit-flag notmuch-address-harvest-proc nil)
> +  ;; return value
> +  nil)
> +
> +;; If we can find the program specified by `notmuch-address-command'
> +;; or if it is nil, insinuate ourselves into `message-mode'.
> +(when (or (eq notmuch-address-command nil)
> +	  (notmuch-address-locate-command notmuch-address-command))
>    (notmuch-address-message-insinuate))
>  
> +(defun notmuch-address-harvest-start ()
> +  (when (not notmuch-address-completions) (notmuch-address-harvest)))
> +
> +(when (eq notmuch-address-command nil)
> +  (add-hook 'message-mode-hook 'notmuch-address-harvest-start))
> +
>  ;;
>  
>  (provide 'notmuch-address)
> diff --git a/emacs/notmuch-company.el b/emacs/notmuch-company.el
> new file mode 100644
> index 0000000..748fcee
> --- /dev/null
> +++ b/emacs/notmuch-company.el
> @@ -0,0 +1,69 @@
> +;; -*-no-byte-compile: t; -*-
> +
> +;; notmuch-company.el --- Mail address completion for notmuch via company-mode
> +
> +;; Author: Trevor Jim <tjim at mac.com>
> +;; Keywords: mail, completion
> +
> +;; This program 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.
> +
> +;; This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
> +
> +;;; Commentary:
> +
> +;; To enable this, install company mode (https://company-mode.github.io/)
> +;; and add
> +;;
> +;;     (require 'notmuch-company)
> +;;
> +;; to your .emacs.
> +;;
> +;; NB company-minimum-prefix-length defaults to 3 so you don't get
> +;; completion unless you type 3 characters
> +
> +;;; Bugs:
> +;;
> +;; - matching is case sensitive
> +;; - matching of non-ascii characters doesn't work well
> +
> +;;; Code:
> +
> +(require 'company)
> +(require 'message)
> +(require 'notmuch-address)
> +
> +(defvar-local notmuch-company-last-prefix nil)
> +;;;###autoload
> +(defun notmuch-company (command &optional arg &rest ignore)
> +  "`company-mode' completion back-end for `notmuch'."
> +  (interactive (list 'interactive))
> +  (let ((case-fold-search t))
> +    (pcase command
> +      (`interactive (company-begin-backend 'notmuch-company))
> +      (`prefix (and (eq major-mode 'message-mode)
> +                    (looking-back "^\\(To\\|Cc\\|Bcc\\):.*"
> +                                  (line-beginning-position))
> +                    (setq notmuch-company-last-prefix (company-grab-symbol))))
> +      (`candidates (let ((results (completion-substring--all-completions arg notmuch-address-completions nil 0)))
> +                     (when results (car results))))
> +      (`match (if (string-match notmuch-company-last-prefix arg)
> +                  (match-end 0)
> +                0))
> +      (`no-cache t))))
> +
> +(add-hook 'message-mode-hook '(lambda ()
> +                                (company-mode)
> +                                (make-local-variable 'company-backends)
> +                                (setq company-backends '(notmuch-company))
> +				(notmuch-address-harvest-start)))
> +
> +(provide 'notmuch-company)
> diff --git a/emacs/notmuch-lib.el b/emacs/notmuch-lib.el
> index 19269e3..00e8554 100644
> --- a/emacs/notmuch-lib.el
> +++ b/emacs/notmuch-lib.el
> @@ -228,6 +228,9 @@ on the command line, and then retry your notmuch command")))
>    "Return the user.other_email value (as a list) from the notmuch configuration."
>    (split-string (notmuch-config-get "user.other_email") "\n" t))
>  
> +(defun notmuch-user-emails ()
> +  (cons (notmuch-user-primary-email) (notmuch-user-other-email)))
> +
>  (defun notmuch-poll ()
>    "Run \"notmuch new\" or an external script to import mail.
>  
> -- 
> 2.0.1