Have curl --follow the location of the things it fetches.

[gnus] / lisp / nnir.el

;;; nnir.el --- search mail with various search engines -*- coding: iso-8859-1 -*-

;; Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
;;   2007, 2008, 2009, 2010 Free Software Foundation, Inc.

;; Author: Kai Großjohann <grossjohann@ls6.cs.uni-dortmund.de>
;; Swish-e and Swish++ backends by:
;;   Christoph Conrad <christoph.conrad@gmx.de>.
;; IMAP backend by: Simon Josefsson <jas@pdc.kth.se>.
;; IMAP search by: Torsten Hilbrich <torsten.hilbrich <at> gmx.net>
;; IMAP search improved by Daniel Pittman  <daniel@rimspace.net>.
;; nnmaildir support for Swish++ and Namazu backends by:
;;   Justus Piater <Justus <at> Piater.name>
;; Keywords: news mail searching ir

;; 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 <http://www.gnu.org/licenses/>.

;;; Commentary:

;; TODO: Documentation in the Gnus manual

;; From: Reiner Steib
;; Subject: Re: Including nnir.el
;; Newsgroups: gmane.emacs.gnus.general
;; Message-ID: <v9d5dnp6aq.fsf@marauder.physik.uni-ulm.de>
;; Date: 2006-06-05 22:49:01 GMT
;;
;; On Sun, Jun 04 2006, Sascha Wilde wrote:
;;
;; > The one thing most hackers like to forget: Documentation.  By now the
;; > documentation is only in the comments at the head of the source, I
;; > would use it as basis to cook up some minimal texinfo docs.
;; >
;; > Where in the existing gnus manual would this fit best?

;; Maybe (info "(gnus)Combined Groups") for a general description.
;; `gnus-group-make-nnir-group' might be described in (info
;; "(gnus)Foreign Groups") as well.


;; The most recent version of this can always be fetched from the Gnus
;; repository.  See http://www.gnus.org/ for more information.

;; This code is still in the development stage but I'd like other
;; people to have a look at it.  Please do not hesitate to contact me
;; with your ideas.

;; What does it do?  Well, it allows you to index your mail using some
;; search engine (freeWAIS-sf, swish-e and others -- see later),
;; then type `G G' in the Group buffer and issue a query to the search
;; engine.  You will then get a buffer which shows all articles
;; matching the query, sorted by Retrieval Status Value (score).

;; When looking at the retrieval result (in the Summary buffer) you
;; can type `G T' (aka M-x gnus-summary-nnir-goto-thread RET) on an
;; article.  You will be teleported into the group this article came
;; from, showing the thread this article is part of.  (See below for
;; restrictions.)

;; The Lisp installation is simple: just put this file on your
;; load-path, byte-compile it, and load it from ~/.gnus or something.
;; This will install a new command `G G' in your Group buffer for
;; searching your mail.  Note that you also need to configure a number
;; of variables, as described below.

;; Restrictions:
;;
;; * If you don't use HyREX as your search engine, this expects that
;;   you use nnml or another one-file-per-message backend, because the
;;   others doesn't support nnfolder.
;; * It can only search the mail backend's which are supported by one
;;   search engine, because of different query languages.
;; * There are restrictions to the Wais setup.
;; * There are restrictions to the imap setup.
;; * gnus-summary-nnir-goto-thread: Fetches whole group first, before
;;   limiting to the right articles.  This is much too slow, of
;;   course.  May issue a query for number of articles to fetch; you
;;   must accept the default of all articles at this point or things
;;   may break.

;; The Lisp setup involves setting a few variables and setting up the
;; search engine. You can define the variables in the server definition
;; like this :
;;   (setq gnus-secondary-select-methods '(
;;       (nnimap "" (nnimap-address "localhost")
;;                  (nnir-search-engine hyrex)
;;                  (nnir-hyrex-additional-switches ("-d" "ddl-nnimap.xml"))
;;       )))
;; Or you can define the global ones. The variables set in the mailer-
;; definition will be used first.
;; The variable to set is `nnir-search-engine'.  Choose one of the engines
;; listed in `nnir-engines'.  (Actually `nnir-engines' is an alist,
;; type `C-h v nnir-engines RET' for more information; this includes
;; examples for setting `nnir-search-engine', too.)
;;
;; The variable nnir-mail-backend isn't used anymore.
;;

;; You must also set up a search engine.  I'll tell you about the two
;; search engines currently supported:

;; 1. freeWAIS-sf
;;
;; As always with freeWAIS-sf, you need a so-called `format file'.  I
;; use the following file:
;;
;; ,-----
;; | # Kai's format file for freeWAIS-sf for indexing mails.
;; | # Each mail is in a file, much like the MH format.
;; |
;; | # Document separator should never match -- each file is a document.
;; | record-sep: /^@this regex should never match@$/
;; |
;; | # Searchable fields specification.
;; |
;; | region: /^[sS]ubject:/ /^[sS]ubject: */
;; |         subject "Subject header" stemming TEXT BOTH
;; | end: /^[^ \t]/
;; |
;; | region: /^([tT][oO]|[cC][cC]):/ /^([tT][oO]|[cC][cC]): */
;; |         to "To and Cc headers" SOUNDEX BOTH
;; | end: /^[^ \t]/
;; |
;; | region: /^[fF][rR][oO][mM]:/ /^[fF][rR][oO][mM]: */
;; |         from "From header" SOUNDEX BOTH
;; | end: /^[^ \t]/
;; |
;; | region: /^$/
;; |         stemming TEXT GLOBAL
;; | end: /^@this regex should never match@$/
;; `-----
;;
;; 1998-07-22: waisindex would dump core on me for large articles with
;; the above settings.  I used /^$/ as the end regex for the global
;; field.  That seemed to work okay.

;; There is a Perl module called `WAIS.pm' which is available from
;; CPAN as well as ls6-ftp.cs.uni-dortmund.de:/pub/wais/Perl.  This
;; module comes with a nifty tool called `makedb', which I use for
;; indexing.  Here's my `makedb.conf':
;;
;; ,-----
;; | # Config file for makedb
;; |
;; | # Global options
;; | waisindex = /usr/local/bin/waisindex
;; | wais_opt  = -stem -t fields
;; | # `-stem' option necessary when `stemming' is specified for the
;; | # global field in the *.fmt file
;; |
;; | # Own variables
;; | homedir = /home/kai
;; |
;; | # The mail database.
;; | database        = mail
;; | files           = `find $homedir/Mail -name \*[0-9] -print`
;; | dbdir           = $homedir/.wais
;; | limit           = 100
;; `-----
;;
;; The Lisp setup involves the `nnir-wais-*' variables.  The most
;; difficult to understand variable is probably
;; `nnir-wais-remove-prefix'.  Here's what it does: the output of
;; `waissearch' basically contains the file name and the (full)
;; directory name.  As Gnus works with group names rather than
;; directory names, the directory name is transformed into a group
;; name as follows: first, a prefix is removed from the (full)
;; directory name, then all `/' are replaced with `.'.  The variable
;; `nnir-wais-remove-prefix' should contain a regex matching exactly
;; this prefix.  It defaults to `$HOME/Mail/' (note the trailing
;; slash).

;; 2. Namazu
;;
;; The Namazu backend requires you to have one directory containing all
;; index files, this is controlled by the `nnir-namazu-index-directory'
;; variable.  To function the `nnir-namazu-remove-prefix' variable must
;; also be correct, see the documentation for `nnir-wais-remove-prefix'
;; above.
;;
;; It is particularly important not to pass any any switches to namazu
;; that will change the output format.  Good switches to use include
;; `--sort', `--ascending', `--early' and `--late'.  Refer to the Namazu
;; documentation for further information on valid switches.
;;
;; To index my mail with the `mknmz' program I use the following
;; configuration file:
;;
;; ,----
;; | package conf;  # Don't remove this line!
;; |
;; | # Paths which will not be indexed. Don't use `^' or `$' anchors.
;; | $EXCLUDE_PATH = "spam|sent";
;; |
;; | # Header fields which should be searchable. case-insensitive
;; | $REMAIN_HEADER = "from|date|message-id|subject";
;; |
;; | # Searchable fields. case-insensitive
;; | $SEARCH_FIELD = "from|date|message-id|subject";
;; |
;; | # The max length of a word.
;; | $WORD_LENG_MAX = 128;
;; |
;; | # The max length of a field.
;; | $MAX_FIELD_LENGTH = 256;
;; `----
;;
;; My mail is stored in the directories ~/Mail/mail/, ~/Mail/lists/ and
;; ~/Mail/archive/, so to index them I go to the directory set in
;; `nnir-namazu-index-directory' and issue the following command.
;;
;;      mknmz --mailnews ~/Mail/archive/ ~/Mail/mail/ ~/Mail/lists/
;;
;; For maximum searching efficiency I have a cron job set to run this
;; command every four hours.

;; 3. HyREX
;;
;; The HyREX backend requires you to have one directory from where all
;; your relative paths are to, if you use them. This directory must be
;; set in the `nnir-hyrex-index-directory' variable, which defaults to
;; your home directory. You must also pass the base, class and
;; directory options or simply your dll to the `nnir-hyrex-programm' by
;; setting the `nnir-hyrex-additional-switches' variable accordently.
;; To function the `nnir-hyrex-remove-prefix' variable must also be
;; correct, see the documentation for `nnir-wais-remove-prefix' above.

;; 4. find-grep
;;
;; The find-grep engine simply runs find(1) to locate eligible
;; articles and searches them with grep(1).  This, of course, is much
;; slower than using a proper search engine but OTOH doesn't require
;; maintenance of an index and is still faster than using any built-in
;; means for searching.  The method specification of the server to
;; search must include a directory for this engine to work (E.g.,
;; `nnml-directory').  The tools must be POSIX compliant.  GNU Find
;; prior to version 4.2.12 (4.2.26 on Linux due to incorrect ARG_MAX
;; handling) does not work.
;; ,----
;; |    ;; find-grep configuration for searching the Gnus Cache
;; |
;; |    (nnml "cache"
;; |          (nnml-get-new-mail nil)
;; |          (nnir-search-engine find-grep)
;; |          (nnml-directory "~/News/cache/")
;; |          (nnml-active-file "~/News/cache/active"))
;; `----

;; Developer information:

;; I have tried to make the code expandable.  Basically, it is divided
;; into two layers.  The upper layer is somewhat like the `nnvirtual'
;; or `nnkiboze' backends: given a specification of what articles to
;; show from another backend, it creates a group containing exactly
;; those articles.  The lower layer issues a query to a search engine
;; and produces such a specification of what articles to show from the
;; other backend.

;; The interface between the two layers consists of the single
;; function `nnir-run-query', which just selects the appropriate
;; function for the search engine one is using.  The input to
;; `nnir-run-query' is a string, representing the query as input by
;; the user.  The output of `nnir-run-query' is supposed to be a
;; vector, each element of which should in turn be a three-element
;; vector.  The first element should be full group name of the article,
;; the second element should be the article number, and the third
;; element should be the Retrieval Status Value (RSV) as returned from
;; the search engine.  An RSV is the score assigned to the document by
;; the search engine.  For Boolean search engines, the
;; RSV is always 1000 (or 1 or 100, or whatever you like).

;; The sorting order of the articles in the summary buffer created by
;; nnir is based on the order of the articles in the above mentioned
;; vector, so that's where you can do the sorting you'd like.  Maybe
;; it would be nice to have a way of displaying the search result
;; sorted differently?

;; So what do you need to do when you want to add another search
;; engine?  You write a function that executes the query.  Temporary
;; data from the search engine can be put in `nnir-tmp-buffer'.  This
;; function should return the list of articles as a vector, as
;; described above.  Then, you need to register this backend in
;; `nnir-engines'.  Then, users can choose the backend by setting
;; `nnir-search-engine'.

;; Todo, or future ideas:

;; * It should be possible to restrict search to certain groups.
;;
;; * There is currently no error checking.
;;
;; * The summary buffer display is currently really ugly, with all the
;;   added information in the subjects.  How could I make this
;;   prettier?
;;
;; * A function which can be called from an nnir summary buffer which
;;   teleports you into the group the current article came from and
;;   shows you the whole thread this article is part of.
;;   Implementation suggestions?
;;   (1998-07-24: There is now a preliminary implementation, but
;;   it is much too slow and quite fragile.)
;;
;; * Support other mail backends.  In particular, probably quite a few
;;   people use nnfolder.  How would one go about searching nnfolders
;;   and producing the right data needed?  The group name and the RSV
;;   are simple, but what about the article number?
;;   - The article number is encoded in the `X-Gnus-Article-Number'
;;     header of each mail.
;;   - The HyREX engine supports nnfolder.
;;
;; * Support compressed mail files.  Probably, just stripping off the
;;   `.gz' or `.Z' file name extension is sufficient.
;;
;; * At least for imap, the query is performed twice.
;;

;; Have you got other ideas?

;;; Setup Code:

(require 'nnoo)
(require 'gnus-group)
(require 'gnus-sum)
(require 'message)
(require 'gnus-util)
(eval-when-compile
  (require 'cl))

(nnoo-declare nnir)
(nnoo-define-basics nnir)

(gnus-declare-backend "nnir" 'mail)

(defvar nnir-imap-search-field "TEXT"
  "The IMAP search item when doing an nnir search")

(defvar nnir-imap-search-arguments
  '(("Whole message" . "TEXT")
    ("Subject" . "SUBJECT")
    ("To" . "TO")
    ("From" . "FROM")
    (nil . "HEADER \"%s\""))
  "Mapping from user readable strings to IMAP search items for use in nnir")

(defvar nnir-imap-search-argument-history ()
  "The history for querying search options in nnir")

(defvar nnir-get-article-nov-override-function nil
  "If non-nil, a function that will be passed each search result.  This
should return a message's headers in NOV format.

If this variable is nil, or if the provided function returns nil for a search
result, `gnus-retrieve-headers' will be called instead.")


;;; Developer Extension Variable:

(defvar nnir-engines
  `((wais    nnir-run-waissearch
             ())
    (imap    nnir-run-imap
             ((criteria
               "Search in: "                      ; Prompt
               ,nnir-imap-search-arguments        ; alist for completing
               nil                                ; no filtering
               nil                                ; allow any user input
               nil                                ; initial value
               nnir-imap-search-argument-history  ; the history to use
               ,nnir-imap-search-field            ; default
               )))
    (swish++ nnir-run-swish++
             ((group . "Group spec: ")))
    (swish-e nnir-run-swish-e
             ((group . "Group spec: ")))
    (namazu  nnir-run-namazu
             ())
    (hyrex   nnir-run-hyrex
             ((group . "Group spec: ")))
  (find-grep nnir-run-find-grep
             ((grep-options . "Grep options: "))))
  "Alist of supported search engines.
Each element in the alist is a three-element list (ENGINE FUNCTION ARGS).
ENGINE is a symbol designating the searching engine.  FUNCTION is also
a symbol, giving the function that does the search.  The third element
ARGS is a list of cons pairs (PARAM . PROMPT).  When issuing a query,
the FUNCTION will issue a query for each of the PARAMs, using PROMPT.

The value of `nnir-search-engine' must be one of the ENGINE symbols.
For example, use the following line for searching using freeWAIS-sf:
    (setq nnir-search-engine 'wais)
Use the following line if you read your mail via IMAP and your IMAP
server supports searching:
    (setq nnir-search-engine 'imap)
Note that you have to set additional variables for most backends.  For
example, the `wais' backend needs the variables `nnir-wais-program',
`nnir-wais-database' and `nnir-wais-remove-prefix'.

Add an entry here when adding a new search engine.")

;;; User Customizable Variables:

(defgroup nnir nil
  "Search nnmh and nnml groups in Gnus with swish-e, freeWAIS-sf, or EWS."
  :group 'gnus)

;; Mail backend.

;; TODO:
;; If `nil', use server parameters to find out which server to search. CCC
;;
(defcustom nnir-mail-backend '(nnml "")
  "*Specifies which backend should be searched.
More precisely, this is used to determine from which backend to fetch the
messages found.

This must be equal to an existing server, so maybe it is best to use
something like the following:
    (setq nnir-mail-backend (nth 0 gnus-secondary-select-methods))
The above line works fine if the mail backend you want to search is
the first element of gnus-secondary-select-methods (`nth' starts counting
at zero)."
  :type '(sexp)
  :group 'nnir)

;; Search engine to use.

(defcustom nnir-search-engine 'wais
  "*The search engine to use.  Must be a symbol.
See `nnir-engines' for a list of supported engines, and for example
settings of `nnir-search-engine'."
  :type '(sexp)
  :group 'nnir)

;; freeWAIS-sf.

(defcustom nnir-wais-program "waissearch"
  "*Name of waissearch executable."
  :type '(string)
  :group 'nnir)

(defcustom nnir-wais-database (expand-file-name "~/.wais/mail")
  "*Name of Wais database containing the mail.

Note that this should be a file name without extension.  For example,
if you have a file /home/john/.wais/mail.fmt, use this:
    (setq nnir-wais-database \"/home/john/.wais/mail\")
The string given here is passed to `waissearch -d' as-is."
  :type '(file)
  :group 'nnir)

(defcustom nnir-wais-remove-prefix (concat (getenv "HOME") "/Mail/")
  "*The prefix to remove from each directory name returned by waissearch
in order to get a group name (albeit with / instead of .).  This is a
regular expression.

For example, suppose that Wais returns file names such as
\"/home/john/Mail/mail/misc/42\".  For this example, use the following
setting:  (setq nnir-wais-remove-prefix \"/home/john/Mail/\")
Note the trailing slash.  Removing this prefix gives \"mail/misc/42\".
`nnir' knows to remove the \"/42\" and to replace \"/\" with \".\" to
arrive at the correct group name, \"mail.misc\"."
  :type '(regexp)
  :group 'nnir)

(defcustom nnir-swish++-configuration-file
  (expand-file-name "~/Mail/swish++.conf")
  "*Configuration file for swish++."
  :type '(file)
  :group 'nnir)

(defcustom nnir-swish++-program "search"
  "*Name of swish++ search executable."
  :type '(string)
  :group 'nnir)

(defcustom nnir-swish++-additional-switches '()
  "*A list of strings, to be given as additional arguments to swish++.

Note that this should be a list.  Ie, do NOT use the following:
    (setq nnir-swish++-additional-switches \"-i -w\") ; wrong
Instead, use this:
    (setq nnir-swish++-additional-switches '(\"-i\" \"-w\"))"
  :type '(repeat (string))
  :group 'nnir)

(defcustom nnir-swish++-remove-prefix (concat (getenv "HOME") "/Mail/")
  "*The prefix to remove from each file name returned by swish++
in order to get a group name (albeit with / instead of .).  This is a
regular expression.

This variable is very similar to `nnir-wais-remove-prefix', except
that it is for swish++, not Wais."
  :type '(regexp)
  :group 'nnir)

;; Swish-E.
;; URL: http://sunsite.berkeley.edu/SWISH-E/
;; New version: http://www.boe.es/swish-e
;; Variables `nnir-swish-e-index-file', `nnir-swish-e-program' and
;; `nnir-swish-e-additional-switches'

(make-obsolete-variable 'nnir-swish-e-index-file
                        'nnir-swish-e-index-files "Emacs 23.1")
(defcustom nnir-swish-e-index-file
  (expand-file-name "~/Mail/index.swish-e")
  "*Index file for swish-e.
This could be a server parameter.
It is never consulted once `nnir-swish-e-index-files', which should be
used instead, has been customized."
  :type '(file)
  :group 'nnir)

(defcustom nnir-swish-e-index-files
  (list nnir-swish-e-index-file)
  "*List of index files for swish-e.
This could be a server parameter."
  :type '(repeat (file))
  :group 'nnir)

(defcustom nnir-swish-e-program "swish-e"
  "*Name of swish-e search executable.
This cannot be a server parameter."
  :type '(string)
  :group 'nnir)

(defcustom nnir-swish-e-additional-switches '()
  "*A list of strings, to be given as additional arguments to swish-e.

Note that this should be a list.  Ie, do NOT use the following:
    (setq nnir-swish-e-additional-switches \"-i -w\") ; wrong
Instead, use this:
    (setq nnir-swish-e-additional-switches '(\"-i\" \"-w\"))

This could be a server parameter."
  :type '(repeat (string))
  :group 'nnir)

(defcustom nnir-swish-e-remove-prefix (concat (getenv "HOME") "/Mail/")
  "*The prefix to remove from each file name returned by swish-e
in order to get a group name (albeit with / instead of .).  This is a
regular expression.

This variable is very similar to `nnir-wais-remove-prefix', except
that it is for swish-e, not Wais.

This could be a server parameter."
  :type '(regexp)
  :group 'nnir)

;; HyREX engine, see <URL:http://ls6-www.cs.uni-dortmund.de/>

(defcustom nnir-hyrex-program "nnir-search"
  "*Name of the nnir-search executable."
  :type '(string)
  :group 'nnir)

(defcustom nnir-hyrex-additional-switches '()
  "*A list of strings, to be given as additional arguments for nnir-search.
Note that this should be a list. Ie, do NOT use the following:
    (setq nnir-hyrex-additional-switches \"-ddl ddl.xml -c nnir\") ; wrong !
Instead, use this:
    (setq nnir-hyrex-additional-switches '(\"-ddl\" \"ddl.xml\" \"-c\" \"nnir\"))"
  :type '(repeat (string))
  :group 'nnir)

(defcustom nnir-hyrex-index-directory (getenv "HOME")
  "*Index directory for HyREX."
  :type '(directory)
  :group 'nnir)

(defcustom nnir-hyrex-remove-prefix (concat (getenv "HOME") "/Mail/")
  "*The prefix to remove from each file name returned by HyREX
in order to get a group name (albeit with / instead of .).

For example, suppose that HyREX returns file names such as
\"/home/john/Mail/mail/misc/42\".  For this example, use the following
setting:  (setq nnir-hyrex-remove-prefix \"/home/john/Mail/\")
Note the trailing slash.  Removing this prefix gives \"mail/misc/42\".
`nnir' knows to remove the \"/42\" and to replace \"/\" with \".\" to
arrive at the correct group name, \"mail.misc\"."
  :type '(directory)
  :group 'nnir)

;; Namazu engine, see <URL:http://ww.namazu.org/>

(defcustom nnir-namazu-program "namazu"
  "*Name of Namazu search executable."
  :type '(string)
  :group 'nnir)

(defcustom nnir-namazu-index-directory (expand-file-name "~/Mail/namazu/")
  "*Index directory for Namazu."
  :type '(directory)
  :group 'nnir)

(defcustom nnir-namazu-additional-switches '()
  "*A list of strings, to be given as additional arguments to namazu.
The switches `-q', `-a', and `-s' are always used, very few other switches
make any sense in this context.

Note that this should be a list.  Ie, do NOT use the following:
    (setq nnir-namazu-additional-switches \"-i -w\") ; wrong
Instead, use this:
    (setq nnir-namazu-additional-switches '(\"-i\" \"-w\"))"
  :type '(repeat (string))
  :group 'nnir)

(defcustom nnir-namazu-remove-prefix (concat (getenv "HOME") "/Mail/")
  "*The prefix to remove from each file name returned by Namazu
in order to get a group name (albeit with / instead of .).

This variable is very similar to `nnir-wais-remove-prefix', except
that it is for Namazu, not Wais."
  :type '(directory)
  :group 'nnir)

;;; Internal Variables:

(defvar nnir-current-query nil
  "Internal: stores current query (= group name).")

(defvar nnir-current-server nil
  "Internal: stores current server (does it ever change?).")

(defvar nnir-current-group-marked nil
  "Internal: stores current list of process-marked groups.")

(defvar nnir-artlist nil
  "Internal: stores search result.")

(defvar nnir-tmp-buffer " *nnir*"
  "Internal: temporary buffer.")

;;; Code:

;; Gnus glue.

(defun gnus-group-make-nnir-group (extra-parms query)
  "Create an nnir group.  Asks for query."
  (interactive "P\nsQuery: ")
  (setq nnir-current-query nil
        nnir-current-server nil
        nnir-current-group-marked nil
        nnir-artlist nil)
  (let ((parms nil))
    (if extra-parms
        (setq parms (nnir-read-parms query))
      (setq parms (list (cons 'query query))))
    (add-to-list 'parms (cons 'unique-id (message-unique-id)) t)
    (gnus-group-read-ephemeral-group
     (concat "nnir:" (prin1-to-string parms)) '(nnir "") t
     (cons (current-buffer)
           gnus-current-window-configuration)
     nil)))

(eval-when-compile
  (when (featurep 'xemacs)
    ;; The `kbd' macro requires that the `read-kbd-macro' macro is available.
    (require 'edmacro)))

(defun nnir-group-mode-hook ()
  (define-key gnus-group-mode-map (kbd "G G")
    'gnus-group-make-nnir-group))
(add-hook 'gnus-group-mode-hook 'nnir-group-mode-hook)

;; Why is this needed? Is this for compatibility with old/new gnusae? Using
;; gnus-group-server instead works for me.  -- Justus Piater
(defmacro nnir-group-server (group)
  "Return the server for a newsgroup GROUP.
The returned format is as `gnus-server-to-method' needs it.  See
`gnus-group-real-prefix' and `gnus-group-real-name'."
  `(let ((gname ,group))
     (if (string-match "^\\([^:]+\\):" gname)
         (progn
           (setq gname (match-string 1 gname))
           (if (string-match "^\\([^+]+\\)\\+\\(.+\\)$" gname)
               (format "%s:%s" (match-string 1 gname) (match-string 2 gname))
             (concat gname ":")))
       (format "%s:%s" (car gnus-select-method) (cadr gnus-select-method)))))

;; Summary mode commands.

(defun gnus-summary-nnir-goto-thread ()
  "Only applies to nnir groups.  Go to group this article came from
and show thread that contains this article."
  (interactive)
  (unless (eq 'nnir (car (gnus-find-method-for-group gnus-newsgroup-name)))
    (error "Can't execute this command unless in nnir group"))
  (let* ((cur (gnus-summary-article-number))
         (group (nnir-artlist-artitem-group nnir-artlist cur))
         (backend-number (nnir-artlist-artitem-number nnir-artlist cur))
         server backend-group)
    (setq server (nnir-group-server group))
    (setq backend-group (gnus-group-real-name group))
    (gnus-group-read-ephemeral-group
     backend-group
     (gnus-server-to-method server)
     t                                  ; activate
     (cons (current-buffer)
           'summary)                    ; window config
     nil
     (list backend-number))
    (gnus-summary-limit (list backend-number))
    (gnus-summary-refer-thread)))

(if (fboundp 'eval-after-load)
    (eval-after-load "gnus-sum"
      '(define-key gnus-summary-goto-map
         "T" 'gnus-summary-nnir-goto-thread))
  (add-hook 'gnus-summary-mode-hook
            (function (lambda ()
                        (define-key gnus-summary-goto-map
                          "T" 'gnus-summary-nnir-goto-thread)))))



;; Gnus backend interface functions.

(deffoo nnir-open-server (server &optional definitions)
  ;; Just set the server variables appropriately.
  (nnoo-change-server 'nnir server definitions))

(deffoo nnir-request-group (group &optional server fast)
  "GROUP is the query string."
  (nnir-possibly-change-server server)
  ;; Check for cache and return that if appropriate.
  (if (and (equal group nnir-current-query)
           (equal gnus-group-marked nnir-current-group-marked)
           (or (null server)
               (equal server nnir-current-server)))
      nnir-artlist
    ;; Cache miss.
    (setq nnir-artlist (nnir-run-query group)))
  (save-excursion
    (set-buffer nntp-server-buffer)
    (if (zerop (length nnir-artlist))
        (progn
          (setq nnir-current-query nil
                nnir-current-server nil
                nnir-current-group-marked nil
                nnir-artlist nil)
          (nnheader-report 'nnir "Search produced empty results."))
      ;; Remember data for cache.
      (setq nnir-current-query group)
      (when server (setq nnir-current-server server))
      (setq nnir-current-group-marked gnus-group-marked)
      (nnheader-insert "211 %d %d %d %s\n"
                       (nnir-artlist-length nnir-artlist) ; total #
                       1              ; first #
                       (nnir-artlist-length nnir-artlist) ; last #
                       group))))     ; group name

(deffoo nnir-retrieve-headers (articles &optional group server fetch-old)
  (save-excursion
    (let ((artlist (copy-sequence articles))
          art artitem artgroup artno artrsv artfullgroup
          novitem novdata foo server)
      (while (not (null artlist))
        (setq art (car artlist))
        (or (numberp art)
            (nnheader-report
             'nnir
             "nnir-retrieve-headers doesn't grok message ids: %s"
             art))
        (setq artitem (nnir-artlist-article nnir-artlist art))
        (setq artrsv (nnir-artitem-rsv artitem))
        (setq artfullgroup (nnir-artitem-group artitem))
        (setq artno (nnir-artitem-number artitem))
        (setq artgroup (gnus-group-real-name artfullgroup))
        (setq server (nnir-group-server artfullgroup))
        ;; retrieve NOV or HEAD data for this article, transform into
        ;; NOV data and prepend to `novdata'
        (set-buffer nntp-server-buffer)
        (nnir-possibly-change-server server)
        (let ((gnus-override-method
               (gnus-server-to-method server)))
          ;; if nnir-get-article-nov-override-function is set, use it
          (if nnir-get-article-nov-override-function
              (setq novitem (funcall nnir-get-article-nov-override-function
                                     artitem))
          ;; else, set novitem through nnheader-parse-nov/nnheader-parse-head
            (case (setq foo (gnus-retrieve-headers (list artno) 
                                                   artfullgroup nil))
              (nov
               (goto-char (point-min))
               (setq novitem (nnheader-parse-nov))
               (unless novitem
                 (pop-to-buffer nntp-server-buffer)
                 (error
                  "nnheader-parse-nov returned nil for article %s in group %s"
                  artno artfullgroup)))
              (headers
               (goto-char (point-min))
               (setq novitem (nnheader-parse-head))
               (unless novitem
                 (pop-to-buffer nntp-server-buffer)
                 (error
                  "nnheader-parse-head returned nil for article %s in group %s"
                  artno artfullgroup)))
              (t (error "Unknown header type %s while requesting article %s of group %s"
                        foo artno artfullgroup)))))
        ;; replace article number in original group with article number
        ;; in nnir group
        (mail-header-set-number novitem art)
        (mail-header-set-from novitem
                              (mail-header-from novitem))
        (mail-header-set-subject
         novitem
         (format "[%d: %s/%d] %s"
                 artrsv artgroup artno
                 (mail-header-subject novitem)))
        ;;-(mail-header-set-extra novitem nil)
        (push novitem novdata)
        (setq artlist (cdr artlist)))
      (setq novdata (nreverse novdata))
      (set-buffer nntp-server-buffer) (erase-buffer)
      (mapc 'nnheader-insert-nov novdata)
      'nov)))

(deffoo nnir-request-article (article
                              &optional group server to-buffer)
  (if (stringp article)
      (nnheader-report
       'nnir
       "nnir-retrieve-headers doesn't grok message ids: %s"
       article)
    (save-excursion
      (let* ((artitem (nnir-artlist-article nnir-artlist
                                            article))
             (artfullgroup (nnir-artitem-group artitem))
             (artno (nnir-artitem-number artitem))
             ;; Bug?
             ;; Why must we bind nntp-server-buffer here?  It won't
             ;; work if `buf' is used, say.  (Of course, the set-buffer
             ;; line below must then be updated, too.)
             (nntp-server-buffer (or to-buffer nntp-server-buffer)))
        (set-buffer nntp-server-buffer)
        (erase-buffer)
        (message "Requesting article %d from group %s"
                 artno artfullgroup)
        (gnus-request-article artno artfullgroup nntp-server-buffer)
        (cons artfullgroup artno)))))


(nnoo-define-skeleton nnir)


(defmacro nnir-add-result (dirnam artno score prefix server artlist)
  "Ask `nnir-compose-result' to construct a result vector,
and if it is non-nil, add it to artlist."
  `(let ((result (nnir-compose-result ,dirnam ,artno ,score ,prefix ,server)))
     (when (not (null result))
       (push result ,artlist))))

(autoload 'nnmaildir-base-name-to-article-number "nnmaildir")

;; Helper function currently used by the Swish++ and Namazu backends;
;; perhaps useful for other backends as well
(defun nnir-compose-result (dirnam article score prefix server)
  "Extract the group from dirnam, and create a result vector
ready to be added to the list of search results."

  ;; remove nnir-*-remove-prefix from beginning of dirnam filename
  (when (string-match (concat "^" prefix) dirnam)
    (setq dirnam (replace-match "" t t dirnam)))

  (when (file-readable-p (concat prefix dirnam article))
    ;; remove trailing slash and, for nnmaildir, cur/new/tmp
    (setq dirnam
          (substring dirnam 0 (if (string= server "nnmaildir:") -5 -1)))

    ;; Set group to dirnam without any leading dots or slashes,
    ;; and with all subsequent slashes replaced by dots
    (let ((group (gnus-replace-in-string
                 (gnus-replace-in-string dirnam "^[./\\]" "" t)
                 "[/\\]" "." t)))

    (vector (nnir-group-full-name group server)
            (if (string= server "nnmaildir:")
                (nnmaildir-base-name-to-article-number
                 (substring article 0 (string-match ":" article))
                 group nil)
              (string-to-number article))
            (string-to-number score)))))

;;; Search Engine Interfaces:

;; freeWAIS-sf interface.
(defun nnir-run-waissearch (query server &optional group)
  "Run given query agains waissearch.  Returns vector of (group name, file name)
pairs (also vectors, actually)."
  (when group
    (error "The freeWAIS-sf backend cannot search specific groups"))
  (save-excursion
    (let ((qstring (cdr (assq 'query query)))
          (prefix (nnir-read-server-parm 'nnir-wais-remove-prefix server))
          artlist score artno dirnam)
      (set-buffer (get-buffer-create nnir-tmp-buffer))
      (erase-buffer)