;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2010-2022 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2015 Alex Kost <alezost@gmail.com>
;;; Copyright © 2019, 2022 Ricardo Wurmus <rekado@elephly.net>
;;; Copyright © 2021 Sarah Morgensen <iskarian@mgsn.dev>
;;; Copyright © 2021, 2022 Maxime Devos <maximedevos@telenet.be>
;;;
;;; 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 url-fetch))
  #:use-module (guix git-download)
  #:use-module (guix gnupg)
  #:use-module (guix packages)
  #:use-module (guix diagnostics)
  #:use-module (guix ui)
  #:use-module (guix base32)
  #:use-module (guix gexp)
  #:autoload   (guix git) (latest-repository-commit git-reference->git-checkout)
  #:use-module (guix hash)
  #:use-module (guix store)
  #:use-module ((guix derivations) #:select (built-derivations derivation->output-path))
  #:autoload   (gcrypt hash) (port-sha256)
  #: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 (srfi srfi-34)
  #:use-module (srfi srfi-35)
  #:use-module (rnrs bytevectors)
  #: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
            upstream-source-input-changes

            url-predicate
            url-prefix-predicate
            coalesce-sources

            upstream-updater
            upstream-updater?
            upstream-updater-name
            upstream-updater-description
            upstream-updater-predicate
            upstream-updater-import

            upstream-input-change?
            upstream-input-change-name
            upstream-input-change-type
            upstream-input-change-action
            changed-inputs

            %updaters
            lookup-updater

            download-tarball
            package-archive-type
            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|git-reference
  (signature-urls upstream-source-signature-urls  ;#f | list of strings
                  (default #f))
  (input-changes  upstream-source-input-changes
                  (default '()) (thunked)))

;; Representation of an upstream input change.
(define-record-type* <upstream-input-change>
  upstream-input-change make-upstream-input-change
  upstream-input-change?
  (name    upstream-input-change-name)    ;string
  (type    upstream-input-change-type)    ;symbol: regular | native | propagated
  (action  upstream-input-change-action)) ;symbol: add | remove

(define (changed-inputs package package-sexp)
  "Return a list of input changes for PACKAGE based on the newly imported
S-expression PACKAGE-SEXP."
  (match package-sexp
    ((and expr ('package fields ...))
     (let* ((input->name (match-lambda ((name pkg . out) name)))
            (new-regular
             (match expr
               ((path *** ('inputs
                           ('quasiquote ((label ('unquote sym)) ...)))) label)
               ((path *** ('inputs
                           ('list sym ...))) (map symbol->string sym))
               (_ '())))
            (new-native
             (match expr
               ((path *** ('native-inputs
                           ('quasiquote ((label ('unquote sym)) ...)))) label)
               ((path *** ('native-inputs
                           ('list sym ...))) (map symbol->string sym))
               (_ '())))
            (new-propagated
             (match expr
               ((path *** ('propagated-inputs
                           ('quasiquote ((label ('unquote sym)) ...)))) label)
               ((path *** ('propagated-inputs
                           ('list sym ...))) (map symbol->string sym))
               (_ '())))
            (current-regular
             (map input->name (package-inputs package)))
            (current-native
             (map input->name (package-native-inputs package)))
            (current-propagated
             (map input->name (package-propagated-inputs package))))
       (append-map
        (match-lambda
          ((action type names)
           (map (lambda (name)
                  (upstream-input-change
                   (name name)
                   (type type)
                   (action action)))
                names)))
        `((add regular
           ,(lset-difference equal?
                             new-regular current-regular))
          (remove regular
           ,(lset-difference equal?
                             current-regular new-regular))
          (add native
           ,(lset-difference equal?
                             new-native current-native))
          (remove native
           ,(lset-difference equal?
                             current-native new-native))
          (add propagated
           ,(lset-difference equal?
                             new-propagated current-propagated))
          (remove propagated
           ,(lset-difference equal?
                             current-propagated new-propagated))))))
    (_ '())))

(define* (url-predicate matching-url?)
  "Return a predicate that returns true when passed a package whose source is
an <origin> with the URL-FETCH method, and one of its URLs passes
MATCHING-URL?."
  (lambda (package)
    (match (package-source package)
      ((? origin? origin)
       (and (eq? (origin-method origin) url-fetch)
            (match (origin-uri origin)
              ((? string? url)
               (matching-url? url))
              (((? string? urls) ...)
               (any matching-url? urls))
              (_
               #f))))
      (_ #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."
  (url-predicate (cut string-prefix? prefix <>)))

(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)
  (import      upstream-updater-import))

(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, alphabetically sorted.
  (delay
    (sort (fold-module-public-variables (lambda (obj result)
                                          (if (upstream-updater? obj)
                                              (cons obj result)
                                              result))
                                        '()
                                        (importer-modules))
          (lambda (updater1 updater2)
            (string<? (symbol->string (upstream-updater-name updater1))
                      (symbol->string (upstream-updater-name updater2)))))))

;; Tests need to mock this variable so mark it as "non-declarative".
(set! %updaters %updaters)

(define* (lookup-updater package
                         #:optional (updaters (force %updaters)))
  "Return an updater among UPDATERS that matches PACKAGE, or #f if none of
them matches."
  (find (match-lambda
          (($ <upstream-updater> name description pred import)
           (pred package)))
        updaters))

(define* (package-latest-release package
                                 #:optional
                                 (updaters (force %updaters)))
  "Return an upstream source to update PACKAGE, a <package> object, or #f if
none of UPDATERS matches PACKAGE.  When several updaters match PACKAGE, try
them until one of them returns an upstream source.  It is the caller's
responsibility to ensure that the returned source is newer than the current
one."
  (any (match-lambda
         (($ <upstream-updater> name description pred import)
          (and (pred package)
               (import package))))
       updaters))

(define* (package-latest-release* package
                                  #:optional
                                  (updaters (force %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))))))))
          (let-values (((status data)
                        (if sig
                            (gnupg-verify* sig data
                                           #:key-download key-download)
                            (values 'missing-signature data))))
            (match status
              ('valid-signature
               tarball)
              ('missing-signature
               (warning (G_ "failed to download detached signature from ~a~%")
                        signature-url)
               #f)
              ('invalid-signature
               (warning (G_ "signature verification failed for '~a' (key: ~a)~%")
                        url data)
               #f)
              ('missing-key
               (warning (G_ "missing public key ~a for '~a'~%")
                        data url)
               #f)))))))

(define (upstream-source-compiler/url-fetch source system)
  "Lower SOURCE, an <upstream-source> pointing to a tarball, as a
fixed-output derivation that would fetch it, and verify its authenticity."
  (mlet* %store-monad ((url -> (first (upstream-source-urls source)))
                       (signature
                        -> (and=> (upstream-source-signature-urls source)
                                  first))
                       (tarball ((store-lift download-tarball) url signature)))
    (unless tarball
      (raise (formatted-message (G_ "failed to fetch source from '~a'")
                                url)))

    ;; Instead of returning TARBALL, return a fixed-output derivation that
    ;; would be able to re-download it.  In practice, since TARBALL is already
    ;; in the store, no extra download will happen, but having the derivation
    ;; in store improves provenance tracking.
    (let ((hash (call-with-input-file tarball port-sha256)))
      (url-fetch url 'sha256 hash (store-path-package-name tarball)
                 #:system system))))

(define (upstream-source-compiler/git-fetch source system)
  "Lower SOURCE, an <upstream-source> using git, as a fixed-output
derivation that would fetch it."
  (mlet* %store-monad ((reference -> (upstream-source-urls source))
                       (checkout
                        (lower-object
                         (git-reference->git-checkout reference)
                         system)))
    ;; Like in 'upstream-source-compiler/url-fetch', return a fixed-output
    ;; derivation instead of CHECKOUT.
    (git-fetch reference 'sha256
               (file-hash* checkout #:recursive? #true #:select? (const #true))
               (git-file-name (upstream-source-package source)
                              (upstream-source-version source))
               #:system system)))

(define-gexp-compiler (upstream-source-compiler (source <upstream-source>)
                                                system target)
  "Download SOURCE, lower it as a fixed-output derivation that would fetch it,
and verify its authenticity if possible."
  (if (git-reference? (upstream-source-urls source))
      (upstream-source-compiler/git-fetch source system)
      (upstream-source-compiler/url-fetch source system)))

(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-archive-type package)
  "If PACKAGE's source is a tarball or zip archive, return its archive type--a
string such as \"xz\".  Otherwise return #f."
  (match (and=> (package-source package) origin-actual-file-name)
    (#f #f)
    (file
     (let ((extension (file-extension file)))
       ;; FILE might be "example-1.2-checkout", in which case we want to
       ;; ignore the extension.
       (and (or (string-contains extension "z")
                (string-contains extension "tar"))
            extension)))))

(define* (package-update/url-fetch store package source
                                   #:key key-download)
  "Return the version, tarball, and SOURCE, to update PACKAGE to
SOURCE, an <upstream-source>."
  (match source
    (($ <upstream-source> _ version urls signature-urls)
     (let*-values (((archive-type)
                    (package-archive-type package))
                   ((url signature-url)
                    ;; Try to find a URL that matches ARCHIVE-TYPE.
                    (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)))))
       ;; If none of URLS matches ARCHIVE-TYPE, then URL is #f; in that case,
       ;; pick up the first element of URLS.
       (let ((tarball (download-tarball store
                                        (or url (first urls))
                                        (and (pair? signature-urls)
                                             (or signature-url
                                                 (first signature-urls)))
                                        #:key-download key-download)))
         (values version tarball source))))))


(define* (package-update/git-fetch store package source #:key key-download)
  "Return the version, checkout, and SOURCE, to update PACKAGE to
SOURCE, an <upstream-source>."
  ;; TODO: it would be nice to authenticate commits, e.g. with
  ;; "guix git authenticate" or a list of permitted signing keys.
  (define ref (upstream-source-urls source)) ; a <git-reference>
  (values (upstream-source-version source)
          (latest-repository-commit
           store
           (git-reference-url ref)
           #:ref `(tag-or-commit . ,(git-reference-commit ref))
           #:recursive? (git-reference-recursive? ref))
          source))

(define %method-updates
  ;; Mapping of origin methods to source update procedures.
  `((,url-fetch . ,package-update/url-fetch)
    (,git-fetch . ,package-update/git-fetch)))

(define* (package-update store package
                         #:optional (updaters (force %updaters))
                         #:key (key-download 'interactive))
  "Return the new version, the file name of the new version tarball, and input
changes for PACKAGE; return #f (three values) when PACKAGE is up-to-date;
raise an error when the updater could not determine available releases.
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? source)
     (if (version>? (upstream-source-version source)
                    (package-version package))
         (let ((method (match (package-source package)
                         ((? origin? origin)
                          (origin-method origin))
                         (_
                          #f))))
           (match (assq method %method-updates)
             (#f
              (raise (make-compound-condition
                      (formatted-message (G_ "cannot download for \
this method: ~s")
                                         method)
                      (condition
                       (&error-location
                        (location (package-location package)))))))
             ((_ . update)
              (update store package source
                      #:key-download key-download))))
         (values #f #f #f)))
    (#f
     ;; Warn rather than abort so that other updates can still take place.
     (warning (G_ "updater failed to determine available releases for ~a~%")
              (package-name package))
     (values #f #f #f))))

(define* (update-package-source package source hash)
  "Modify the source file that defines PACKAGE to refer to SOURCE, an
<upstream-source> whose tarball has SHA256 HASH (a bytevector).  Return the
new version string if an update was made, and #f otherwise."
  (define (update-expression expr replacements)
    ;; Apply REPLACEMENTS to package expression EXPR, a string.  REPLACEMENTS
    ;; must be a list of replacement pairs, either bytevectors or strings.
    (fold (lambda (replacement str)
            (match replacement
              (((? bytevector? old-bv) . (? bytevector? new-bv))
               (string-replace-substring
                str
                (bytevector->nix-base32-string old-bv)
                (bytevector->nix-base32-string new-bv)))
              ((old . new)
               (string-replace-substring str old new))))
          expr
          replacements))

  (let ((name        (package-name package))
        (version     (upstream-source-version source))
        (version-loc (package-field-location package 'version)))
    (if version-loc
        (let* ((loc         (package-location package))
               (old-version (package-version package))
               (old-hash    (content-hash-value
                             (origin-hash (package-source package))))
               (old-url     (match (origin-uri (package-source package))
                              ((? string? url) url)
                              ((? git-reference? ref)
                               (git-reference-url ref))
                              (_ #f)))
               (new-url     (match (upstream-source-urls source)
                              ((first _ ...) first)
                              ((? git-reference? ref)
                               (git-reference-url ref))
                              (_ #f)))
               (old-commit  (match (origin-uri (package-source package))
                              ((? git-reference? ref)
                               (git-reference-commit ref))
                              (_ #f)))
               (new-commit  (match (upstream-source-urls source)
                              ((? git-reference? ref)
                               (git-reference-commit ref))
                              (_ #f)))
               (file        (and=> (location-file loc)
                                   (cut search-path %load-path <>))))
          (if file
              ;; Be sure to use absolute filename.  Replace the URL directory
              ;; when OLD-URL is available; this is useful notably for
              ;; mirror://cpan/ URLs where the directory may change as a
              ;; function of the person who uploads the package.  Note that
              ;; package definitions usually concatenate fragments of the URL,
              ;; which is why we only attempt to replace a subset of the URL.
              (let ((properties (assq-set! (location->source-properties loc)
                                           'filename file))
                    (replacements `((,old-version . ,version)
                                    (,old-hash . ,hash)
                                    ,@(if (and old-commit new-commit)
                                          `((,old-commit . ,new-commit))
                                          '())
                                    ,@(if (and old-url new-url)
                                          `((,(dirname old-url) .
                                             ,(dirname new-url)))
                                          '()))))
                (and (edit-expression properties
                                      (cut update-expression <> replacements))
                     version))
              (begin
                (warning (G_ "~a: could not locate source file")
                         (location-file loc))
                #f)))
        (warning (package-location package)
                 (G_ "~a: no `version' field in source; skipping~%")
                 name))))

;;; upstream.scm ends here