;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2015 Alex Kost <alezost@gmail.com>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix 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 Guix 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 Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (guix upstream)
  #:use-module (guix records)
  #:use-module (guix utils)
  #:use-module (guix discovery)
  #:use-module ((guix download)
                #:select (download-to-store))
  #:use-module (guix gnupg)
  #:use-module (guix packages)
  #:use-module (guix ui)
  #:use-module (guix base32)
  #:use-module (guix gexp)
  #:use-module (guix store)
  #:use-module ((guix derivations)
                #:select (built-derivations derivation->output-path))
  #:use-module (guix monads)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-9)
  #:use-module (srfi srfi-11)
  #:use-module (srfi srfi-26)
  #:use-module (ice-9 match)
  #:use-module (ice-9 regex)
  #:export (upstream-source
            upstream-source?
            upstream-source-package
            upstream-source-version
            upstream-source-urls
            upstream-source-signature-urls
            upstream-source-archive-types

            url-prefix-predicate
            coalesce-sources

            upstream-updater
            upstream-updater?
            upstream-updater-name
            upstream-updater-description
            upstream-updater-predicate
            upstream-updater-latest

            %updaters
            lookup-updater

            download-tarball
            package-latest-release
            package-latest-release*
            package-update
            update-package-source))

;;; Commentary:
;;;
;;; This module provides tools to represent and manipulate a upstream source
;;; code, and to auto-update package recipes.
;;;
;;; Code:

;; Representation of upstream's source.  There can be several URLs--e.g.,
;; tar.gz, tar.gz, etc.  There can be correspond signature URLs, one per
;; source URL.
(define-record-type* <upstream-source>
  upstream-source make-upstream-source
  upstream-source?
  (package        upstream-source-package)        ;string
  (version        upstream-source-version)        ;string
  (urls           upstream-source-urls)           ;list of strings
  (signature-urls upstream-source-signature-urls  ;#f | list of strings
                  (default #f)))

(define (url-prefix-predicate prefix)
  "Return a predicate that returns true when passed a package where one of its
source URLs starts with PREFIX."
  (lambda (package)
    (define matching-uri?
      (match-lambda
        ((? string? uri)
         (string-prefix? prefix uri))
        (_
         #f)))

    (match (package-source package)
      ((? origin? origin)
       (match (origin-uri origin)
         ((? matching-uri?) #t)
         (_                 #f)))
      (_ #f))))

(define (upstream-source-archive-types release)
  "Return the available types of archives for RELEASE---a list of strings such
as \"gz\" or \"xz\"."
  (map file-extension (upstream-source-urls release)))

(define (coalesce-sources sources)
  "Coalesce the elements of SOURCES, a list of <upstream-source>, that
correspond to the same version."
  (define (same-version? r1 r2)
    (string=? (upstream-source-version r1) (upstream-source-version r2)))

  (define (release>? r1 r2)
    (version>? (upstream-source-version r1) (upstream-source-version r2)))

  (fold (lambda (release result)
          (match result
            ((head . tail)
             (if (same-version? release head)
                 (cons (upstream-source
                        (inherit release)
                        (urls (append (upstream-source-urls release)
                                      (upstream-source-urls head)))
                        (signature-urls
                         (let ((one (upstream-source-signature-urls release))
                               (two (upstream-source-signature-urls head)))
                           (and one two (append one two)))))
                       tail)
                 (cons release result)))
            (()
             (list release))))
        '()
        (sort sources release>?)))


;;;
;;; Auto-update.
;;;

(define-record-type* <upstream-updater>
  upstream-updater make-upstream-updater
  upstream-updater?
  (name        upstream-updater-name)
  (description upstream-updater-description)
  (pred        upstream-updater-predicate)
  (latest      upstream-updater-latest))

(define (importer-modules)
  "Return the list of importer modules."
  (cons (resolve-interface '(guix gnu-maintenance))
        (all-modules (map (lambda (entry)
                            `(,entry . "guix/import"))
                          %load-path)
                     #:warn warn-about-load-error)))

(define %updaters
  ;; The list of publically-known updaters.
  (delay (fold-module-public-variables (lambda (obj result)
                                         (if (upstream-updater? obj)
                                             (cons obj result)
                                             result))
                                       '()
                                       (importer-modules))))

(define (lookup-updater package updaters)
  "Return an updater among UPDATERS that matches PACKAGE, or #f if none of
them matches."
  (any (match-lambda
         (($ <upstream-updater> name description pred latest)
          (and (pred package) latest)))
       updaters))

(define (package-latest-release package updaters)
  "Return an upstream source to update PACKAGE, a <package> object, or #f if
none of UPDATERS matches PACKAGE.  It is the caller's responsibility to ensure
that the returned source is newer than the current one."
  (match (lookup-updater package updaters)
    ((? procedure? latest-release)
     (latest-release package))
    (_ #f)))

(define (package-latest-release* package updaters)
  "Like 'package-latest-release', but ensure that the return source is newer
than that of PACKAGE."
  (match (package-latest-release package updaters)
    ((and source ($ <upstream-source> name version))
     (and (version>? version (package-version package))
          source))
    (_
     #f)))

(define (uncompressed-tarball name tarball)
  "Return a derivation that decompresses TARBALL."
  (define (ref package)
    (module-ref (resolve-interface '(gnu packages compression))
                package))

  (define compressor
    (cond ((or (string-suffix? ".gz" tarball)
               (string-suffix? ".tgz" tarball))
           (file-append (ref 'gzip) "/bin/gzip"))
          ((string-suffix? ".bz2" tarball)
           (file-append (ref 'bzip2) "/bin/bzip2"))
          ((string-suffix? ".xz" tarball)
           (file-append (ref 'xz) "/bin/xz"))
          ((string-suffix? ".lz" tarball)
           (file-append (ref 'lzip) "/bin/lzip"))
          (else
           (error "unknown archive type" tarball))))

  (gexp->derivation (file-sans-extension name)
                    #~(begin
                        (copy-file #+tarball #+name)
                        (and (zero? (system* #+compressor "-d" #+name))
                             (copy-file #+(file-sans-extension name)
                                        #$output)))))

(define* (download-tarball store url signature-url
                           #:key (key-download 'interactive))
  "Download the tarball at URL to the store; check its OpenPGP signature at
SIGNATURE-URL, unless SIGNATURE-URL is false.  On success, return the tarball
file name; return #f on failure (network failure or authentication failure).
KEY-DOWNLOAD specifies a download policy for missing OpenPGP keys; allowed
values: 'interactive' (default), 'always', and 'never'."
  (let ((tarball (download-to-store store url)))
    (if (not signature-url)
        tarball
        (let* ((sig  (download-to-store store signature-url))

               ;; Sometimes we get a signature over the uncompressed tarball.
               ;; In that case, decompress the tarball in the store so that we
               ;; can check the signature.
               (data (if (string-prefix? (basename url)
                                         (basename signature-url))
                         tarball
                         (run-with-store store
                           (mlet %store-monad ((drv (uncompressed-tarball
                                                     (basename url) tarball)))
                             (mbegin %store-monad
                               (built-derivations (list drv))
                               (return (derivation->output-path drv)))))))

               (ret  (gnupg-verify* sig data #:key-download key-download)))
          (if ret
              tarball
              (begin
                (warning (G_ "signature verification failed for `~a'~%")
                         url)
                (warning (G_ "(could be because the public key is not in your keyring)~%"))
                #f))))))

(define (find2 pred lst1 lst2)
  "Like 'find', but operate on items from both LST1 and LST2.  Return two
values: the item from LST1 and the item from LST2 that match PRED."
  (let loop ((lst1 lst1) (lst2 lst2))
    (match lst1
      ((head1 . tail1)
       (match lst2
         ((head2 . tail2)
          (if (pred head1 head2)
              (values head1 head2)
              (loop tail1 tail2)))))
      (()
       (values #f #f)))))

(define* (package-update store package updaters
                         #:key (key-download 'interactive))
  "Return the new version and the file name of the new version tarball for
PACKAGE, or #f and #f when PACKAGE is up-to-date.  KEY-DOWNLOAD specifies a
download policy for missing OpenPGP keys; allowed values: 'always', 'never',
and 'interactive' (default)."
  (match (package-latest-release* package updaters)
    (($ <upstream-source> _ version urls signature-urls)
     (let*-values (((name)
                    (package-name package))
                   ((archive-type)
                    (match (and=> (package-source package) origin-uri)
                      ((? string? uri)
                       (let ((type (file-extension (basename uri))))
                         ;; Sometimes we have URLs such as
                         ;; "https://github.com/…/tarball/v0.1", in which case
                         ;; we must not consider "1" as the extension.
                         (and (or (string-contains type "z")
                                  (string=? type "tar"))
                              type)))
                      (_
                       "gz")))
                   ((url signature-url)
                    (find2 (lambda (url sig-url)
                             ;; Some URIs lack a file extension, like
                             ;; 'https://crates.io/???/0.1/download'.  In that
                             ;; case, pick the first URL.
                             (or (not archive-type)
                                 (string-suffix? archive-type url)))
                           urls
                           (or signature-urls (circular-list #f)))))
       (let ((tarball (download-tarball store url signature-url
                                        #:key-download key-download)))
         (values version tarball))))
    (#f
     (values #f #f))))

(define (update-package-source package version hash)
  "Modify the source file that defines PACKAGE to refer to VERSION,
whose tarball has SHA256 HASH (a bytevector).  Return the new version string
if an update was made, and #f otherwise."
  (define (update-expression expr old-version version old-hash hash)
    ;; Update package expression EXPR, replacing occurrences OLD-VERSION by
    ;; VERSION and occurrences of OLD-HASH by HASH (base32 representation
    ;; thereof).
    (let ((old-hash (bytevector->nix-base32-string old-hash))
          (hash     (bytevector->nix-base32-string hash)))
      (string-replace-substring
       (string-replace-substring expr old-hash hash)
       old-version version)))

  (let ((name        (package-name package))
        (version-loc (package-field-location package 'version)))
    (if version-loc
        (let* ((loc         (package-location package))
               (old-version (package-version package))
               (old-hash    (origin-sha256 (package-source package)))
               (file        (and=> (location-file loc)
                                   (cut search-path %load-path <>))))
          (if file
              (and (edit-expression
                    ;; Be sure to use absolute filename.
                    (assq-set! (location->source-properties loc)
                               'filename file)
                    (cut update-expression <>
                         old-version version old-hash hash))
                   version)
              (begin
                (warning (G_ "~a: could not locate source file")
                         (location-file loc))
                #f)))
        (begin
          (format (current-error-port)
                  (G_ "~a: ~a: no `version' field in source; skipping~%")
                  (location->string (package-location package))
                  name)))))

;;; upstream.scm ends here