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;;; package.el --- Simple package system for Emacs  -*- lexical-binding:t -*-
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;; Copyright (C) 2007-2014 Free Software Foundation, Inc.
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;; Author: Tom Tromey <tromey@redhat.com>
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;;         Daniel Hackney <dan@haxney.org>
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;; Created: 10 Mar 2007
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;; Version: 1.0.1
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;; Keywords: tools
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;; Package-Requires: ((tabulated-list "1.0"))
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;; This file is part of GNU Emacs.

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;; GNU Emacs is free software: you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
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;; 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
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;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
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;;; Change Log:

;;  2 Apr 2007 - now using ChangeLog file
;; 15 Mar 2007 - updated documentation
;; 14 Mar 2007 - Changed how obsolete packages are handled
;; 13 Mar 2007 - Wrote package-install-from-buffer
;; 12 Mar 2007 - Wrote package-menu mode

;;; Commentary:

;; The idea behind package.el is to be able to download packages and
;; install them.  Packages are versioned and have versioned
;; dependencies.  Furthermore, this supports built-in packages which
;; may or may not be newer than user-specified packages.  This makes
;; it possible to upgrade Emacs and automatically disable packages
;; which have moved from external to core.  (Note though that we don't
;; currently register any of these, so this feature does not actually
;; work.)

;; A package is described by its name and version.  The distribution
;; format is either  a tar file or a single .el file.

;; A tar file should be named "NAME-VERSION.tar".  The tar file must
;; unpack into a directory named after the package and version:
;; "NAME-VERSION".  It must contain a file named "PACKAGE-pkg.el"
;; which consists of a call to define-package.  It may also contain a
;; "dir" file and the info files it references.

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;; A .el file is named "NAME-VERSION.el" in the remote archive, but is
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;; installed as simply "NAME.el" in a directory named "NAME-VERSION".

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;; The downloader downloads all dependent packages.  By default,
;; packages come from the official GNU sources, but others may be
;; added by customizing the `package-archives' alist.  Packages get
;; byte-compiled at install time.
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;; At activation time we will set up the load-path and the info path,
;; and we will load the package's autoloads.  If a package's
;; dependencies are not available, we will not activate that package.

;; Conceptually a package has multiple state transitions:
;;
;; * Download.  Fetching the package from ELPA.
;; * Install.  Untar the package, or write the .el file, into
;;   ~/.emacs.d/elpa/ directory.
;; * Byte compile.  Currently this phase is done during install,
;;   but we may change this.
;; * Activate.  Evaluate the autoloads for the package to make it
;;   available to the user.
;; * Load.  Actually load the package and run some code from it.

;; Other external functions you may want to use:
;;
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;; M-x list-packages
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;;    Enters a mode similar to buffer-menu which lets you manage
;;    packages.  You can choose packages for install (mark with "i",
;;    then "x" to execute) or deletion (not implemented yet), and you
;;    can see what packages are available.  This will automatically
;;    fetch the latest list of packages from ELPA.
;;
;; M-x package-install-from-buffer
;;    Install a package consisting of a single .el file that appears
;;    in the current buffer.  This only works for packages which
;;    define a Version header properly; package.el also supports the
;;    extension headers Package-Version (in case Version is an RCS id
;;    or similar), and Package-Requires (if the package requires other
;;    packages).
;;
;; M-x package-install-file
;;    Install a package from the indicated file.  The package can be
;;    either a tar file or a .el file.  A tar file must contain an
;;    appropriately-named "-pkg.el" file; a .el file must be properly
;;    formatted as with package-install-from-buffer.

;;; Thanks:
;;; (sorted by sort-lines):

;; Jim Blandy <jimb@red-bean.com>
;; Karl Fogel <kfogel@red-bean.com>
;; Kevin Ryde <user42@zip.com.au>
;; Lawrence Mitchell
;; Michael Olson <mwolson@member.fsf.org>
;; Sebastian Tennant <sebyte@smolny.plus.com>
;; Stefan Monnier <monnier@iro.umontreal.ca>
;; Vinicius Jose Latorre <viniciusjl@ig.com.br>
;; Phil Hagelberg <phil@hagelb.org>

;;; ToDo:

;; - putting info dirs at the start of the info path means
;;   users see a weird ordering of categories.  OTOH we want to
;;   override later entries.  maybe emacs needs to enforce
;;   the standard layout?
;; - put bytecode in a separate directory tree
;; - perhaps give users a way to recompile their bytecode
;;   or do it automatically when emacs changes
;; - give users a way to know whether a package is installed ok
;; - give users a way to view a package's documentation when it
;;   only appears in the .el
;; - use/extend checkdoc so people can tell if their package will work
;; - "installed" instead of a blank in the status column
;; - tramp needs its files to be compiled in a certain order.
;;   how to handle this?  fix tramp?
;; - on emacs 21 we don't kill the -autoloads.el buffer.  what about 22?
;; - maybe we need separate .elc directories for various emacs versions
;;   and also emacs-vs-xemacs.  That way conditional compilation can
;;   work.  But would this break anything?
;; - should store the package's keywords in archive-contents, then
;;   let the users filter the package-menu by keyword.  See
;;   finder-by-keyword.  (We could also let people view the
;;   Commentary, but it isn't clear how useful this is.)
;; - William Xu suggests being able to open a package file without
;;   installing it
;; - Interface with desktop.el so that restarting after an install
;;   works properly
;; - Use hierarchical layout.  PKG/etc PKG/lisp PKG/info
;;   ... except maybe lisp?
;; - It may be nice to have a macro that expands to the package's
;;   private data dir, aka ".../etc".  Or, maybe data-directory
;;   needs to be a list (though this would be less nice)
;;   a few packages want this, eg sokoban
;; - package menu needs:
;;     ability to know which packages are built-in & thus not deletable
;;     it can sometimes print odd results, like 0.3 available but 0.4 active
;;        why is that?
;; - Allow multiple versions on the server...?
;;   [ why bother? ]
;; - Don't install a package which will invalidate dependencies overall
;; - Allow something like (or (>= emacs 21.0) (>= xemacs 21.5))
;;   [ currently thinking, why bother.. KISS ]
;; - Allow optional package dependencies
;;   then if we require 'bbdb', bbdb-specific lisp in lisp/bbdb
;;   and just don't compile to add to load path ...?
;; - Our treatment of the info path is somewhat bogus

;;; Code:

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(eval-when-compile (require 'cl-lib))
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(eval-when-compile (require 'epg))      ;For setf accessors.
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(require 'tabulated-list)
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(require 'macroexp)
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(defgroup package nil
  "Manager for Emacs Lisp packages."
  :group 'applications
  :version "24.1")

;;;###autoload
(defcustom package-enable-at-startup t
  "Whether to activate installed packages when Emacs starts.
If non-nil, packages are activated after reading the init file
and before `after-init-hook'.  Activation is not done if
`user-init-file' is nil (e.g. Emacs was started with \"-q\").

Even if the value is nil, you can type \\[package-initialize] to
activate the package system at any time."
  :type 'boolean
  :group 'package
  :version "24.1")

(defcustom package-load-list '(all)
  "List of packages for `package-initialize' to load.
Each element in this list should be a list (NAME VERSION), or the
symbol `all'.  The symbol `all' says to load the latest installed
versions of all packages not specified by other elements.

For an element (NAME VERSION), NAME is a package name (a symbol).
VERSION should be t, a string, or nil.
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If VERSION is t, the most recent version is activated.
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If VERSION is a string, only that version is ever loaded.
 Any other version, even if newer, is silently ignored.
 Hence, the package is \"held\" at that version.
If VERSION is nil, the package is not loaded (it is \"disabled\")."
  :type '(repeat symbol)
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  :risky t
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  :group 'package
  :version "24.1")

(defvar Info-directory-list)
(declare-function info-initialize "info" ())
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(declare-function url-http-file-exists-p "url-http" (url))
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(declare-function lm-header "lisp-mnt" (header))
(declare-function lm-commentary "lisp-mnt" (&optional file))

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(defcustom package-archives '(("gnu" . "http://elpa.gnu.org/packages/"))
  "An alist of archives from which to fetch.
The default value points to the GNU Emacs package repository.
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Each element has the form (ID . LOCATION).
 ID is an archive name, as a string.
 LOCATION specifies the base location for the archive.
  If it starts with \"http:\", it is treated as a HTTP URL;
  otherwise it should be an absolute directory name.
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  (Other types of URL are currently not supported.)

Only add locations that you trust, since fetching and installing
a package can run arbitrary code."
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  :type '(alist :key-type (string :tag "Archive name")
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                :value-type (string :tag "URL or directory name"))
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  :risky t
  :group 'package
  :version "24.1")
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(defcustom package-pinned-packages nil
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  "An alist of packages that are pinned to specific archives.
This can be useful if you have multiple package archives enabled,
and want to control which archive a given package gets installed from.

Each element of the alist has the form (PACKAGE . ARCHIVE), where:
 PACKAGE is a symbol representing a package
 ARCHIVE is a string representing an archive (it should be the car of
an element in `package-archives', e.g. \"gnu\").

Adding an entry to this variable means that only ARCHIVE will be
considered as a source for PACKAGE.  If other archives provide PACKAGE,
they are ignored (for this package).  If ARCHIVE does not contain PACKAGE,
the package will be unavailable."
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  :type '(alist :key-type (symbol :tag "Package")
                :value-type (string :tag "Archive name"))
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  ;; I don't really see why this is risky...
  ;; I suppose it could prevent you receiving updates for a package,
  ;; via an entry (PACKAGE . NON-EXISTING).  Which could be an issue
  ;; if PACKAGE has a known vulnerability that is fixed in newer versions.
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  :risky t
  :group 'package
  :version "24.4")

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(defconst package-archive-version 1
  "Version number of the package archive understood by this file.
Lower version numbers than this will probably be understood as well.")

;; We don't prime the cache since it tends to get out of date.
(defvar package-archive-contents nil
  "Cache of the contents of the Emacs Lisp Package Archive.
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This is an alist mapping package names (symbols) to
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non-empty lists of `package-desc' structures.")
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(put 'package-archive-contents 'risky-local-variable t)
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(defcustom package-user-dir (locate-user-emacs-file "elpa")
  "Directory containing the user's Emacs Lisp packages.
The directory name should be absolute.
Apart from this directory, Emacs also looks for system-wide
packages in `package-directory-list'."
  :type 'directory
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  :risky t
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  :group 'package
  :version "24.1")

(defcustom package-directory-list
  ;; Defaults are subdirs named "elpa" in the site-lisp dirs.
  (let (result)
    (dolist (f load-path)
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      (and (stringp f)
	   (equal (file-name-nondirectory f) "site-lisp")
	   (push (expand-file-name "elpa" f) result)))
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    (nreverse result))
  "List of additional directories containing Emacs Lisp packages.
Each directory name should be absolute.

These directories contain packages intended for system-wide; in
contrast, `package-user-dir' contains packages for personal use."
  :type '(repeat directory)
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  :risky t
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  :group 'package
  :version "24.1")

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(defvar epg-gpg-program)

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(defcustom package-check-signature
  (if (progn (require 'epg-config) (executable-find epg-gpg-program))
      'allow-unsigned)
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  "Non-nil means to check package signatures when installing.
The value `allow-unsigned' means to still install a package even if
it is unsigned.

This also applies to the \"archive-contents\" file that lists the
contents of the archive."
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  :type '(choice (const nil :tag "Never")
		 (const allow-unsigned :tag "Allow unsigned")
		 (const t :tag "Check always"))
  :risky t
  :group 'package
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  :version "24.4")
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(defcustom package-unsigned-archives nil
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  "List of archives where we do not check for package signatures."
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  :type '(repeat (string :tag "Archive name"))
  :risky t
  :group 'package
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  :version "24.4")
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(defvar package--default-summary "No description available.")

(cl-defstruct (package-desc
               ;; Rename the default constructor from `make-package-desc'.
               (:constructor package-desc-create)
               ;; Has the same interface as the old `define-package',
               ;; which is still used in the "foo-pkg.el" files. Extra
               ;; options can be supported by adding additional keys.
               (:constructor
                package-desc-from-define
                (name-string version-string &optional summary requirements
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                 &rest rest-plist
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                 &aux
                 (name (intern name-string))
                 (version (version-to-list version-string))
                 (reqs (mapcar #'(lambda (elt)
                                   (list (car elt)
                                         (version-to-list (cadr elt))))
                               (if (eq 'quote (car requirements))
                                   (nth 1 requirements)
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                                 requirements)))
                 (kind (plist-get rest-plist :kind))
                 (archive (plist-get rest-plist :archive))
                 (extras (let (alist)
                           (while rest-plist
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                             (unless (memq (car rest-plist) '(:kind :archive))
                               (let ((value (cadr rest-plist)))
                                 (when value
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                                   (push (cons (car rest-plist)
                                               (if (eq (car-safe value) 'quote)
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                                                   (cadr value)
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                                                 value))
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                                         alist))))
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                             (setq rest-plist (cddr rest-plist)))
                           alist)))))
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  "Structure containing information about an individual package.
Slots:

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`name'	Name of the package, as a symbol.
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`version' Version of the package, as a version list.

`summary' Short description of the package, typically taken from
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	the first line of the file.
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`reqs'	Requirements of the package. A list of (PACKAGE
	VERSION-LIST) naming the dependent package and the minimum
	required version.
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`kind'	The distribution format of the package. Currently, it is
	either `single' or `tar'.
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`archive' The name of the archive (as a string) whence this
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	package came.
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`dir'	The directory where the package is installed (if installed),
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	`builtin' if it is built-in, or nil otherwise.

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`extras' Optional alist of additional keyword-value pairs.

`signed' Flag to indicate that the package is signed by provider."
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  name
  version
  (summary package--default-summary)
  reqs
  kind
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  archive
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  dir
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  extras
  signed)
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;; Pseudo fields.
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(defun package-desc-full-name (pkg-desc)
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  (format "%s-%s"
          (package-desc-name pkg-desc)
          (package-version-join (package-desc-version pkg-desc))))
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(defun package-desc-suffix (pkg-desc)
  (pcase (package-desc-kind pkg-desc)
    (`single ".el")
    (`tar ".tar")
    (kind (error "Unknown package kind: %s" kind))))

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(defun package-desc--keywords (pkg-desc)
  (let ((keywords (cdr (assoc :keywords (package-desc-extras pkg-desc)))))
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    (if (eq (car-safe keywords) 'quote)
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        (nth 1 keywords)
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      keywords)))

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;; Package descriptor format used in finder-inf.el and package--builtins.
(cl-defstruct (package--bi-desc
               (:constructor package-make-builtin (version summary))
               (:type vector))
  version
  reqs
  summary)

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(defvar package--builtins nil
  "Alist of built-in packages.
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The actual value is initialized by loading the library
`finder-inf'; this is not done until it is needed, e.g. by the
function `package-built-in-p'.

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Each element has the form (PKG . PACKAGE-BI-DESC), where PKG is a package
name (a symbol) and DESC is a `package--bi-desc' structure.")
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(put 'package--builtins 'risky-local-variable t)
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(defvar package-alist nil
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  "Alist of all packages available for activation.
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Each element has the form (PKG . DESCS), where PKG is a package
name (a symbol) and DESCS is a non-empty list of `package-desc' structure,
sorted by decreasing versions.
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This variable is set automatically by `package-load-descriptor',
called via `package-initialize'.  To change which packages are
loaded and/or activated, customize `package-load-list'.")
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(put 'package-alist 'risky-local-variable t)
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(defvar package-activated-list nil
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  ;; FIXME: This should implicitly include all builtin packages.
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  "List of the names of currently activated packages.")
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(put 'package-activated-list 'risky-local-variable t)
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(defun package-version-join (vlist)
  "Return the version string corresponding to the list VLIST.
This is, approximately, the inverse of `version-to-list'.
\(Actually, it returns only one of the possible inverses, since
`version-to-list' is a many-to-one operation.)"
  (if (null vlist)
      ""
    (let ((str-list (list "." (int-to-string (car vlist)))))
      (dolist (num (cdr vlist))
	(cond
	 ((>= num 0)
	  (push (int-to-string num) str-list)
	  (push "." str-list))
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	 ((< num -4)
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	  (error "Invalid version list `%s'" vlist))
	 (t
	  ;; pre, or beta, or alpha
	  (cond ((equal "." (car str-list))
		 (pop str-list))
		((not (string-match "[0-9]+" (car str-list)))
		 (error "Invalid version list `%s'" vlist)))
	  (push (cond ((= num -1) "pre")
		      ((= num -2) "beta")
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		      ((= num -3) "alpha")
                      ((= num -4) "snapshot"))
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		str-list))))
      (if (equal "." (car str-list))
	  (pop str-list))
      (apply 'concat (nreverse str-list)))))
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(defun package-load-descriptor (pkg-dir)
  "Load the description file in directory PKG-DIR."
  (let ((pkg-file (expand-file-name (package--description-file pkg-dir)
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                                    pkg-dir))
	(signed-file (concat pkg-dir ".signed")))
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    (when (file-exists-p pkg-file)
      (with-temp-buffer
        (insert-file-contents pkg-file)
        (goto-char (point-min))
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        (let ((pkg-desc (package-process-define-package
                         (read (current-buffer)) pkg-file)))
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          (setf (package-desc-dir pkg-desc) pkg-dir)
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	  (if (file-exists-p signed-file)
	      (setf (package-desc-signed pkg-desc) t))
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          pkg-desc)))))
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(defun package-load-all-descriptors ()
  "Load descriptors for installed Emacs Lisp packages.
This looks for package subdirectories in `package-user-dir' and
`package-directory-list'.  The variable `package-load-list'
controls which package subdirectories may be loaded.

In each valid package subdirectory, this function loads the
description file containing a call to `define-package', which
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updates `package-alist'."
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  (dolist (dir (cons package-user-dir package-directory-list))
    (when (file-directory-p dir)
      (dolist (subdir (directory-files dir))
        (let ((pkg-dir (expand-file-name subdir dir)))
          (when (file-directory-p pkg-dir)
            (package-load-descriptor pkg-dir)))))))

(defun package-disabled-p (pkg-name version)
  "Return whether PKG-NAME at VERSION can be activated.
The decision is made according to `package-load-list'.
Return nil if the package can be activated.
Return t if the package is completely disabled.
Return the max version (as a string) if the package is held at a lower version."
  (let ((force (assq pkg-name package-load-list)))
    (cond ((null force) (not (memq 'all package-load-list)))
          ((null (setq force (cadr force))) t) ; disabled
          ((eq force t) nil)
          ((stringp force)              ; held
           (unless (version-list-= version (version-to-list force))
             force))
          (t (error "Invalid element in `package-load-list'")))))
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(defun package-activate-1 (pkg-desc &optional reload)
  "Activate package given by PKG-DESC, even if it was already active.
If RELOAD is non-nil, also `load' any files inside the package which
correspond to previously loaded files (those returned by
`package--list-loaded-files')."
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  (let* ((name (package-desc-name pkg-desc))
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	 (pkg-dir (package-desc-dir pkg-desc))
         (pkg-dir-dir (file-name-as-directory pkg-dir)))
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    (unless pkg-dir
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      (error "Internal error: unable to find directory for `%s'"
	     (package-desc-full-name pkg-desc)))
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    ;; Add to load path, add autoloads, and activate the package.
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    (let* ((old-lp load-path)
           (autoloads-file (expand-file-name
                            (format "%s-autoloads" name) pkg-dir))
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           (loaded-files-list (and reload (package--list-loaded-files pkg-dir))))
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      (with-demoted-errors (format "Error loading %s: %%s" name)
        (load autoloads-file nil t))
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      (when (and (eq old-lp load-path)
                 (not (or (member pkg-dir load-path)
                          (member pkg-dir-dir load-path))))
        ;; Old packages don't add themselves to the `load-path', so we have to
        ;; do it ourselves.
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        (push pkg-dir load-path))
      ;; Call `load' on all files in `pkg-dir' already present in
      ;; `load-history'.  This is done so that macros in these files are updated
      ;; to their new definitions.  If another package is being installed which
      ;; depends on this new definition, not doing this update would cause
      ;; compilation errors and break the installation.
      (with-demoted-errors (format "Error loading %s: %%s" name)
	(mapc (lambda (feature) (load feature nil t))
              ;; Skip autoloads file since we already evaluated it above.
              (remove (file-truename autoloads-file) loaded-files-list))))
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    ;; Add info node.
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    (when (file-exists-p (expand-file-name "dir" pkg-dir))
      ;; FIXME: not the friendliest, but simple.
      (require 'info)
      (info-initialize)
      (push pkg-dir Info-directory-list))
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    (push name package-activated-list)
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    ;; Don't return nil.
    t))

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(defun package--list-loaded-files (dir)
  "Recursively list all files in DIR which correspond to loaded features.
Returns the `file-name-sans-extension' of each file, relative to
DIR, sorted by most recently loaded last."
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  (let* ((history (delq nil
                        (mapcar (lambda (x)
                                  (let ((f (car x)))
                                    (and f (file-name-sans-extension f))))
                                load-history)))
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         (dir (file-truename dir))
         ;; List all files that have already been loaded.
         (list-of-conflicts
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          (delq
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           nil
           (mapcar
               (lambda (x) (let* ((file (file-relative-name x dir))
                             ;; Previously loaded file, if any.
                             (previous
                              (ignore-errors
                                (file-name-sans-extension
                                 (file-truename (find-library-name file)))))
                             (pos (when previous (member previous history))))
                        ;; Return (RELATIVE-FILENAME . HISTORY-POSITION)
                        (when pos
                          (cons (file-name-sans-extension file) (length pos)))))
             (directory-files-recursively dir "\\`[^\\.].*\\.el\\'")))))
    ;; Turn the list of (FILENAME . POS) back into a list of features.  Files in
    ;; subdirectories are returned relative to DIR (so not actually features).
    (let ((default-directory (file-name-as-directory dir)))
      (mapcar (lambda (x) (file-truename (car x)))
        (sort list-of-conflicts
              ;; Sort the files by ascending HISTORY-POSITION.
              (lambda (x y) (< (cdr x) (cdr y))))))))

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(defun package-built-in-p (package &optional min-version)
  "Return true if PACKAGE is built-in to Emacs.
Optional arg MIN-VERSION, if non-nil, should be a version list
specifying the minimum acceptable version."
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  (if (package-desc-p package) ;; was built-in and then was converted
      (eq 'builtin (package-desc-dir package))
    (let ((bi (assq package package--builtin-versions)))
      (cond
       (bi (version-list-<= min-version (cdr bi)))
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       ((remove 0 min-version) nil)
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       (t
        (require 'finder-inf nil t) ; For `package--builtins'.
        (assq package package--builtins))))))
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(defun package--from-builtin (bi-desc)
  (package-desc-create :name (pop bi-desc)
                       :version (package--bi-desc-version bi-desc)
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                       :summary (package--bi-desc-summary bi-desc)
                       :dir 'builtin))
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;; This function goes ahead and activates a newer version of a package
;; if an older one was already activated.  This is not ideal; we'd at
;; least need to check to see if the package has actually been loaded,
;; and not merely activated.
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(defun package-activate (package &optional force)
  "Activate package PACKAGE.
If FORCE is true, (re-)activate it if it's already activated."
  (let ((pkg-descs (cdr (assq package package-alist))))
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    ;; Check if PACKAGE is available in `package-alist'.
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    (while
        (when pkg-descs
          (let ((available-version (package-desc-version (car pkg-descs))))
            (or (package-disabled-p package available-version)
                ;; Prefer a builtin package.
                (package-built-in-p package available-version))))
      (setq pkg-descs (cdr pkg-descs)))
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    (cond
     ;; If no such package is found, maybe it's built-in.
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     ((null pkg-descs)
      (package-built-in-p package))
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     ;; If the package is already activated, just return t.
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     ((and (memq package package-activated-list) (not force))
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      t)
     ;; Otherwise, proceed with activation.
     (t
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      (let* ((pkg-vec (car pkg-descs))
             (fail (catch 'dep-failure
                     ;; Activate its dependencies recursively.
                     (dolist (req (package-desc-reqs pkg-vec))
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                       (unless (package-activate (car req))
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                         (throw 'dep-failure req))))))
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	(if fail
	    (warn "Unable to activate package `%s'.
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Required package `%s-%s' is unavailable"
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		  package (car fail) (package-version-join (cadr fail)))
	  ;; If all goes well, activate the package itself.
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	  (package-activate-1 pkg-vec force)))))))
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(defun define-package (_name-string _version-string
                                    &optional _docstring _requirements
                                    &rest _extra-properties)
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  "Define a new package.
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NAME-STRING is the name of the package, as a string.
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VERSION-STRING is the version of the package, as a string.
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DOCSTRING is a short description of the package, a string.
REQUIREMENTS is a list of dependencies on other packages.
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 Each requirement is of the form (OTHER-PACKAGE OTHER-VERSION),
 where OTHER-VERSION is a string.
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EXTRA-PROPERTIES is currently unused."
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  ;; FIXME: Placeholder!  Should we keep it?
  (error "Don't call me!"))

(defun package-process-define-package (exp origin)
  (unless (eq (car-safe exp) 'define-package)
    (error "Can't find define-package in %s" origin))
  (let* ((new-pkg-desc (apply #'package-desc-from-define (cdr exp)))
         (name (package-desc-name new-pkg-desc))
         (version (package-desc-version new-pkg-desc))
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         (old-pkgs (assq name package-alist)))
    (if (null old-pkgs)
        ;; If there's no old package, just add this to `package-alist'.
        (push (list name new-pkg-desc) package-alist)
      ;; If there is, insert the new package at the right place in the list.
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      (while
          (if (and (cdr old-pkgs)
                   (version-list-< version
                                   (package-desc-version (cadr old-pkgs))))
              (setq old-pkgs (cdr old-pkgs))
            (push new-pkg-desc (cdr old-pkgs))
            nil)))
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    new-pkg-desc))
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;; From Emacs 22, but changed so it adds to load-path.
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(defun package-autoload-ensure-default-file (file)
  "Make sure that the autoload file FILE exists and if not create it."
  (unless (file-exists-p file)
    (write-region
     (concat ";;; " (file-name-nondirectory file)
	     " --- automatically extracted autoloads\n"
	     ";;\n"
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	     ";;; Code:\n"
             "(add-to-list 'load-path (or (file-name-directory #$) (car load-path)))\n"
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	     "\n;; Local Variables:\n"
	     ";; version-control: never\n"
	     ";; no-byte-compile: t\n"
	     ";; no-update-autoloads: t\n"
	     ";; End:\n"
	     ";;; " (file-name-nondirectory file)
	     " ends here\n")
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     nil file nil 'silent))
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  file)

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(defvar generated-autoload-file)
(defvar version-control)

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(defun package-generate-autoloads (name pkg-dir)
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  (let* ((auto-name (format "%s-autoloads.el" name))
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	 ;;(ignore-name (concat name "-pkg.el"))
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	 (generated-autoload-file (expand-file-name auto-name pkg-dir))
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         (backup-inhibited t)
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	 (version-control 'never))
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    (package-autoload-ensure-default-file generated-autoload-file)
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    (update-directory-autoloads pkg-dir)
    (let ((buf (find-buffer-visiting generated-autoload-file)))
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      (when buf (kill-buffer buf)))
    auto-name))
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(defvar tar-parse-info)
(declare-function tar-untar-buffer "tar-mode" ())
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(declare-function tar-header-name "tar-mode" (tar-header) t)
(declare-function tar-header-link-type "tar-mode" (tar-header) t)
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(defun package-untar-buffer (dir)
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  "Untar the current buffer.
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This uses `tar-untar-buffer' from Tar mode.  All files should
untar into a directory named DIR; otherwise, signal an error."
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  (require 'tar-mode)
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  (tar-mode)
  ;; Make sure everything extracts into DIR.
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  (let ((regexp (concat "\\`" (regexp-quote (expand-file-name dir)) "/"))
	(case-fold-search (memq system-type '(windows-nt ms-dos cygwin))))
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    (dolist (tar-data tar-parse-info)
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      (let ((name (expand-file-name (tar-header-name tar-data))))
	(or (string-match regexp name)
	    ;; Tarballs created by some utilities don't list
	    ;; directories with a trailing slash (Bug#13136).
	    (and (string-equal dir name)
		 (eq (tar-header-link-type tar-data) 5))
	    (error "Package does not untar cleanly into directory %s/" dir)))))
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  (tar-untar-buffer))
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(defun package-generate-description-file (pkg-desc pkg-file)
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  "Create the foo-pkg.el file for single-file packages."
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  (let* ((name (package-desc-name pkg-desc)))
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    (let ((print-level nil)
          (print-quoted t)
          (print-length nil))
      (write-region
       (concat
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        ";;; -*- no-byte-compile: t -*-\n"
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        (prin1-to-string
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         (nconc
          (list 'define-package
                (symbol-name name)
                (package-version-join (package-desc-version pkg-desc))
                (package-desc-summary pkg-desc)
                (let ((requires (package-desc-reqs pkg-desc)))
                  (list 'quote
                        ;; Turn version lists into string form.
                        (mapcar
                         (lambda (elt)
                           (list (car elt)
                                 (package-version-join (cadr elt))))
                         requires))))
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          (package--alist-to-plist-args
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           (package-desc-extras pkg-desc))))
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        "\n")
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       nil pkg-file nil 'silent))))
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(defun package--alist-to-plist-args (alist)
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  (mapcar 'macroexp-quote
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          (apply #'nconc
                 (mapcar (lambda (pair) (list (car pair) (cdr pair))) alist))))
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(defun package-unpack (pkg-desc)
  "Install the contents of the current buffer as a package."
  (let* ((name (package-desc-name pkg-desc))
         (dirname (package-desc-full-name pkg-desc))
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	 (pkg-dir (expand-file-name dirname package-user-dir)))
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    (pcase (package-desc-kind pkg-desc)
      (`tar
       (make-directory package-user-dir t)
       ;; FIXME: should we delete PKG-DIR if it exists?
       (let* ((default-directory (file-name-as-directory package-user-dir)))
         (package-untar-buffer dirname)))
      (`single
       (let ((el-file (expand-file-name (format "%s.el" name) pkg-dir)))
         (make-directory pkg-dir t)
         (package--write-file-no-coding el-file)))
      (kind (error "Unknown package kind: %S" kind)))
    (package--make-autoloads-and-stuff pkg-desc pkg-dir)
    ;; Update package-alist.
    (let ((new-desc (package-load-descriptor pkg-dir)))
      ;; FIXME: Check that `new-desc' matches `desc'!
      ;; FIXME: Compilation should be done as a separate, optional, step.
      ;; E.g. for multi-package installs, we should first install all packages
      ;; and then compile them.
      (package--compile new-desc))
    ;; Try to activate it.
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    (package-activate name 'force)
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    pkg-dir))

(defun package--make-autoloads-and-stuff (pkg-desc pkg-dir)
  "Generate autoloads, description file, etc.. for PKG-DESC installed at PKG-DIR."
  (package-generate-autoloads (package-desc-name pkg-desc) pkg-dir)
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  (let ((desc-file (expand-file-name (package--description-file pkg-dir)
                                     pkg-dir)))
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    (unless (file-exists-p desc-file)
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      (package-generate-description-file pkg-desc desc-file)))
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  ;; FIXME: Create foo.info and dir file from foo.texi?
  )

(defun package--compile (pkg-desc)
  "Byte-compile installed package PKG-DESC."
  (package-activate-1 pkg-desc)
  (byte-recompile-directory (package-desc-dir pkg-desc) 0 t))
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(defun package--write-file-no-coding (file-name)
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  (let ((buffer-file-coding-system 'no-conversion))
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    (write-region (point-min) (point-max) file-name nil 'silent)))
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(defmacro package--with-work-buffer (location file &rest body)
  "Run BODY in a buffer containing the contents of FILE at LOCATION.
LOCATION is the base location of a package archive, and should be
one of the URLs (or file names) specified in `package-archives'.
FILE is the name of a file relative to that base location.

This macro retrieves FILE from LOCATION into a temporary buffer,
and evaluates BODY while that buffer is current.  This work
buffer is killed afterwards.  Return the last value in BODY."
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  (declare (indent 2) (debug t))
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  `(with-temp-buffer
     (if (string-match-p "\\`https?:" ,location)
	 (url-insert-file-contents (concat ,location ,file))
       (unless (file-name-absolute-p ,location)
	 (error "Archive location %s is not an absolute file name"
		,location))
       (insert-file-contents (expand-file-name ,file ,location)))
     ,@body))
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(defun package--archive-file-exists-p (location file)
  (let ((http (string-match "\\`https?:" location)))
    (if http
	(progn
	  (require 'url-http)
	  (url-http-file-exists-p (concat location file)))
      (file-exists-p (expand-file-name file location)))))

(declare-function epg-make-context "epg"
		  (&optional protocol armor textmode include-certs
			     cipher-algorithm
			     digest-algorithm
			     compress-algorithm))
(declare-function epg-verify-string "epg" (context signature
						   &optional signed-text))
(declare-function epg-context-result-for "epg" (context name))
(declare-function epg-signature-status "epg" (signature))
(declare-function epg-signature-to-string "epg" (signature))

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(defun package--display-verify-error (context sig-file)
  (unless (equal (epg-context-error-output context) "")
    (with-output-to-temp-buffer "*Error*"
      (with-current-buffer standard-output
	(if (epg-context-result-for context 'verify)
	    (insert (format "Failed to verify signature %s:\n" sig-file)
		    (mapconcat #'epg-signature-to-string
			       (epg-context-result-for context 'verify)
			       "\n"))
	  (insert (format "Error while verifying signature %s:\n" sig-file)))
	(insert "\nCommand output:\n" (epg-context-error-output context))))))

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(defun package--check-signature (location file)
  "Check signature of the current buffer.
GnuPG keyring is located under \"gnupg\" in `package-user-dir'."
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  (let* ((context (epg-make-context 'OpenPGP))
         (homedir (expand-file-name "gnupg" package-user-dir))
         (sig-file (concat file ".sig"))
         (sig-content (package--with-work-buffer location sig-file
			(buffer-string))))
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    (setf (epg-context-home-directory context) homedir)
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    (condition-case error
	(epg-verify-string context sig-content (buffer-string))
      (error
       (package--display-verify-error context sig-file)
       (signal (car error) (cdr error))))
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    (let (good-signatures had-fatal-error)
      ;; The .sig file may contain multiple signatures.  Success if one
      ;; of the signatures is good.
      (dolist (sig (epg-context-result-for context 'verify))
	(if (eq (epg-signature-status sig) 'good)
	    (push sig good-signatures)
	  ;; If package-check-signature is allow-unsigned, don't
	  ;; signal error when we can't verify signature because of
	  ;; missing public key.  Other errors are still treated as
	  ;; fatal (bug#17625).
	  (unless (and (eq package-check-signature 'allow-unsigned)
		       (eq (epg-signature-status sig) 'no-pubkey))
	    (setq had-fatal-error t))))
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      (when (and (null good-signatures) had-fatal-error)
	(package--display-verify-error context sig-file)
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	(error "Failed to verify signature %s" sig-file))
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      good-signatures)))
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(defun package-install-from-archive (pkg-desc)
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  "Download and install a tar package."
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  (let* ((location (package-archive-base pkg-desc))
	 (file (concat (package-desc-full-name pkg-desc)
		       (package-desc-suffix pkg-desc)))
	 (sig-file (concat file ".sig"))
	 good-signatures pkg-descs)
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    (package--with-work-buffer location file
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      (if (and package-check-signature
	       (not (member (package-desc-archive pkg-desc)
			    package-unsigned-archives)))
	  (if (package--archive-file-exists-p location sig-file)
	      (setq good-signatures (package--check-signature location file))
	    (unless (eq package-check-signature 'allow-unsigned)
	      (error "Unsigned package: `%s'"
		     (package-desc-name pkg-desc)))))
      (package-unpack pkg-desc))
    ;; Here the package has been installed successfully, mark it as
    ;; signed if appropriate.
    (when good-signatures
      ;; Write out good signatures into NAME-VERSION.signed file.
      (write-region (mapconcat #'epg-signature-to-string good-signatures "\n")
		    nil
		    (expand-file-name
		     (concat (package-desc-full-name pkg-desc)
			     ".signed")
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		     package-user-dir)
                    nil 'silent)
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      ;; Update the old pkg-desc which will be shown on the description buffer.
      (setf (package-desc-signed pkg-desc) t)
      ;; Update the new (activated) pkg-desc as well.
      (setq pkg-descs (cdr (assq (package-desc-name pkg-desc) package-alist)))
      (if pkg-descs
	  (setf (package-desc-signed (car pkg-descs)) t)))))
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(defvar package--initialized nil)

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(defun package-installed-p (package &optional min-version)
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  "Return true if PACKAGE, of MIN-VERSION or newer, is installed.
MIN-VERSION should be a version list."
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  (unless package--initialized (error "package.el is not yet initialized!"))
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  (or
   (let ((pkg-descs (cdr (assq package package-alist))))
     (and pkg-descs
	  (version-list-<= min-version
			   (package-desc-version (car pkg-descs)))))
   ;; Also check built-in packages.
   (package-built-in-p package min-version)))
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(defun package-compute-transaction (packages requirements &optional seen)
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  "Return a list of packages to be installed, including PACKAGES.
PACKAGES should be a list of `package-desc'.
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REQUIREMENTS should be a list of additional requirements; each
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element in this list should have the form (PACKAGE VERSION-LIST),
where PACKAGE is a package name and VERSION-LIST is the required
version of that package.
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This function recursively computes the requirements of the
packages in REQUIREMENTS, and returns a list of all the packages
that must be installed.  Packages that are already installed are
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not included in this list.

SEEN is used internally to detect infinite recursion."
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  ;; FIXME: We really should use backtracking to explore the whole
  ;; search space (e.g. if foo require bar-1.3, and bar-1.4 requires toto-1.1
  ;; whereas bar-1.3 requires toto-1.0 and the user has put a hold on toto-1.0:
  ;; the current code might fail to see that it could install foo by using the
  ;; older bar-1.3).
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  (dolist (elt requirements)
    (let* ((next-pkg (car elt))
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	   (next-version (cadr elt))
           (already ()))
      (dolist (pkg packages)
        (if (eq next-pkg (package-desc-name pkg))
            (setq already pkg)))
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      (when already
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        (if (version-list-<= next-version (package-desc-version already))
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            ;; `next-pkg' is already in `packages', but its position there
            ;; means it might be installed too late: remove it from there, so
            ;; we re-add it (along with its dependencies) at an earlier place
            ;; below (bug#16994).
            (if (memq already seen)     ;Avoid inf-loop on dependency cycles.
                (message "Dependency cycle going through %S"
                         (package-desc-full-name already))
              (setq packages (delq already packages))
              (setq already nil))
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          (error "Need package `%s-%s', but only %s is being installed"
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                 next-pkg (package-version-join next-version)
                 (package-version-join (package-desc-version already)))))
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      (cond
       (already nil)
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       ((package-installed-p next-pkg next-version) nil)

       (t
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	;; A package is required, but not installed.  It might also be
	;; blocked via `package-load-list'.
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	(let ((pkg-descs (cdr (assq next-pkg package-archive-contents)))
              (found nil)
              (problem nil))
          (while (and pkg-descs (not found))
            (let* ((pkg-desc (pop pkg-descs))
                   (version (package-desc-version pkg-desc))
                   (disabled (package-disabled-p next-pkg version)))
              (cond
               ((version-list-< version next-version)
                (error
                 "Need package `%s-%s', but only %s is available"
                 next-pkg (package-version-join next-version)
                 (package-version-join version)))
               (disabled
                (unless problem
                  (setq problem
                        (if (stringp disabled)
                            (format "Package `%s' held at version %s, \
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but version %s required"
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                                    next-pkg disabled
                                    (package-version-join next-version))
                          (format "Required package '%s' is disabled"
                                  next-pkg)))))
               (t (setq found pkg-desc)))))
	  (unless found
            (if problem
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                (error "%s" problem)
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              (error "Package `%s-%s' is unavailable"
                     next-pkg (package-version-join next-version))))
	  (setq packages
		(package-compute-transaction (cons found packages)
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					     (package-desc-reqs found)
                                             (cons found seen))))))))
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  packages)
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(defun package-read-from-string (str)
  "Read a Lisp expression from STR.
Signal an error if the entire string was not used."
  (let* ((read-data (read-from-string str))
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	 (more-left
	  (condition-case nil
	      ;; The call to `ignore' suppresses a compiler warning.
	      (progn (ignore (read-from-string
			      (substring str (cdr read-data))))
		     t)
	    (end-of-file nil))))
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    (if more-left
        (error "Can't read whole string")
      (car read-data))))

(defun package--read-archive-file (file)
  "Re-read archive file FILE, if it exists.
Will return the data from the file, or nil if the file does not exist.
Will throw an error if the archive version is too new."
  (let ((filename (expand-file-name file package-user-dir)))
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    (when (file-exists-p filename)
      (with-temp-buffer
	(insert-file-contents-literally filename)
	(let ((contents (read (current-buffer))))
	  (if (> (car contents) package-archive-version)
	      (error "Package archive version %d is higher than %d"
		     (car contents) package-archive-version))
	  (cdr contents))))))
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(defun package-read-all-archive-contents ()
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  "Re-read `archive-contents', if it exists.
If successful, set `package-archive-contents'."
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  (setq package-archive-contents nil)
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  (dolist (archive package-archives)
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    (package-read-archive-contents (car archive))))
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(defun package-read-archive-contents (archive)
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  "Re-read archive contents for ARCHIVE.
If successful, set the variable `package-archive-contents'.
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If the archive version is too new, signal an error."
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  ;; Version 1 of 'archive-contents' is identical to our internal
  ;; representation.
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  (let* ((contents-file (format "archives/%s/archive-contents" archive))
	 (contents (package--read-archive-file contents-file)))
    (when contents
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      (dolist (package contents)
	(package--add-to-archive-contents package archive)))))
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;; Package descriptor objects used inside the "archive-contents" file.
;; Changing this defstruct implies changing the format of the
;; "archive-contents" files.
(cl-defstruct (package--ac-desc
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               (:constructor package-make-ac-desc (version reqs summary kind extras))
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               (:copier nil)
               (:type vector))
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  version reqs summary kind extras)
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(defun package--add-to-archive-contents (package archive)
  "Add the PACKAGE from the given ARCHIVE if necessary.
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PACKAGE should have the form (NAME . PACKAGE--AC-DESC).
Also, add the originating archive to the `package-desc' structure."
  (let* ((name (car package))
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         (version (package--ac-desc-version (cdr package)))
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         (pkg-desc
          (package-desc-create
           :name name
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           :version version
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           :reqs (package--ac-desc-reqs (cdr package))
           :summary (package--ac-desc-summary (cdr package))
           :kind (package--ac-desc-kind (cdr package))
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           :archive archive
           :extras (and (> (length (cdr package)) 4)
                        ;; Older archive-contents files have only 4
                        ;; elements here.
                        (package--ac-desc-extras (cdr package)))))
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         (existing-packages (assq name package-archive-contents))
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         (pinned-to-archive (assoc name package-pinned-packages)))
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    (cond
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     ;; Skip entirely if pinned to another archive.
     ((and pinned-to-archive
           (not (equal (cdr pinned-to-archive) archive)))
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      nil)
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     ((not existing-packages)
      (push (list name pkg-desc) package-archive-contents))
     (t
      (while
          (if (and (cdr existing-packages)
                   (version-list-<
                    version (package-desc-version (cadr existing-packages))))
              (setq existing-packages (cdr existing-packages))
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            (push pkg-desc (cdr existing-packages))
            nil))))))
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(defun package-download-transaction (packages)
  "Download and install all the packages in PACKAGES.
PACKAGES should be a list of package-desc.
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This function assumes that all package requirements in
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PACKAGES are satisfied, i.e. that PACKAGES is computed
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using `package-compute-transaction'."
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  (mapc #'package-install-from-archive packages))
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;;;###autoload
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(defun package-install (pkg)
  "Install the package PKG.
PKG can be a package-desc or the package name of one the available packages
in an archive in `package-archives'.  Interactively, prompt for its name."
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  (interactive
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   (progn
     ;; Initialize the package system to get the list of package
     ;; symbols for completion.
     (unless package--initialized
       (package-initialize t))