;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017, 2018 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2013 Mark H Weaver <mhw@netris.org>
;;; Copyright © 2014 Eric Bavier <bavier@member.fsf.org>
;;; Copyright © 2016, 2017 Alex Kost <alezost@gmail.com>
;;; Copyright © 2016 Mathieu Lirzin <mthl@gnu.org>
;;;
;;; 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 (gnu packages)
  #:use-module (guix packages)
  #:use-module (guix ui)
  #:use-module (guix utils)
  #:use-module (guix discovery)
  #:use-module (guix memoization)
  #:use-module ((guix build utils)
                #:select ((package-name->name+version
                           . hyphen-separated-name->name+version)))
  #:autoload   (guix profiles) (packages->manifest)
  #:use-module (guix describe)
  #:use-module (ice-9 vlist)
  #:use-module (ice-9 match)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-11)
  #:use-module (srfi srfi-26)
  #:use-module (srfi srfi-34)
  #:use-module (srfi srfi-35)
  #:use-module (srfi srfi-39)
  #:export (search-patch
            search-patches
            search-auxiliary-file
            search-bootstrap-binary
            %patch-path
            %auxiliary-files-path
            %bootstrap-binaries-path
            %package-module-path
            %default-package-module-path

            fold-packages

            find-packages-by-name
            find-best-packages-by-name
            find-newest-available-packages

            specification->package
            specification->package+output
            specifications->manifest))

;;; Commentary:
;;;
;;; General utilities for the software distribution---i.e., the modules under
;;; (gnu packages ...).
;;;
;;; Code:

;; By default, we store patches, auxiliary files and bootstrap binaries
;; alongside Guile modules.  This is so that these extra files can be
;; found without requiring a special setup, such as a specific
;; installation directory and an extra environment variable.  One
;; advantage of this setup is that everything just works in an
;; auto-compilation setting.

(define %bootstrap-binaries-path
  (make-parameter
   (map (cut string-append <> "/gnu/packages/bootstrap")
        %load-path)))

(define %auxiliary-files-path
  (make-parameter
   (map (cut string-append <> "/gnu/packages/aux-files")
        %load-path)))

(define (search-auxiliary-file file-name)
  "Search the auxiliary FILE-NAME.  Return #f if not found."
  (search-path (%auxiliary-files-path) file-name))

(define (search-patch file-name)
  "Search the patch FILE-NAME.  Raise an error if not found."
  (or (search-path (%patch-path) file-name)
      (raise (condition
              (&message (message (format #f (G_ "~a: patch not found")
                                         file-name)))))))

(define-syntax-rule (search-patches file-name ...)
  "Return the list of absolute file names corresponding to each
FILE-NAME found in %PATCH-PATH."
  (list (search-patch file-name) ...))

(define (search-bootstrap-binary file-name system)
  "Search the bootstrap binary FILE-NAME for SYSTEM.  Raise an error if not
found."
  (or (search-path (%bootstrap-binaries-path)
                   (string-append system "/" file-name))
      (raise (condition
              (&message
               (message
                (format #f (G_ "could not find bootstrap binary '~a' \
for system '~a'")
                        file-name system)))))))

(define %distro-root-directory
  ;; Absolute file name of the module hierarchy.  Since (gnu packages …) might
  ;; live in a directory different from (guix), try to get the best match.
  (letrec-syntax ((dirname* (syntax-rules ()
                              ((_ file)
                               (dirname file))
                              ((_ file head tail ...)
                               (dirname (dirname* file tail ...)))))
                  (try      (syntax-rules ()
                              ((_ (file things ...) rest ...)
                               (match (search-path %load-path file)
                                 (#f
                                  (try rest ...))
                                 (absolute
                                  (dirname* absolute things ...))))
                              ((_)
                               #f))))
    (try ("gnu/packages/base.scm" gnu/ packages/)
         ("gnu/packages.scm"      gnu/)
         ("guix.scm"))))

(define %default-package-module-path
  ;; Default search path for package modules.
  `((,%distro-root-directory . "gnu/packages")))

(define %package-module-path
  ;; Search path for package modules.  Each item must be either a directory
  ;; name or a pair whose car is a directory and whose cdr is a sub-directory
  ;; to narrow the search.
  (let* ((not-colon   (char-set-complement (char-set #\:)))
         (environment (string-tokenize (or (getenv "GUIX_PACKAGE_PATH") "")
                                       not-colon))
         (channels    (package-path-entries)))
    ;; Automatically add channels and items from $GUIX_PACKAGE_PATH to Guile's
    ;; search path.  For historical reasons, $GUIX_PACKAGE_PATH goes to the
    ;; front; channels go to the back so that they don't override Guix' own
    ;; modules.
    (set! %load-path
      (append environment %load-path channels))
    (set! %load-compiled-path
      (append environment %load-compiled-path channels))

    (make-parameter
     (append environment
             %default-package-module-path
             channels))))

(define %patch-path
  ;; Define it after '%package-module-path' so that '%load-path' contains user
  ;; directories, allowing patches in $GUIX_PACKAGE_PATH to be found.
  (make-parameter
   (map (lambda (directory)
          (if (string=? directory %distro-root-directory)
              (string-append directory "/gnu/packages/patches")
              directory))
        %load-path)))

(define* (fold-packages proc init
                        #:optional
                        (modules (all-modules (%package-module-path)
                                              #:warn
                                              warn-about-load-error))
                        #:key (select? (negate hidden-package?)))
  "Call (PROC PACKAGE RESULT) for each available package defined in one of
MODULES that matches SELECT?, using INIT as the initial value of RESULT.  It
is guaranteed to never traverse the same package twice."
  (fold-module-public-variables (lambda (object result)
                                  (if (and (package? object) (select? object))
                                      (proc object result)
                                      result))
                                init
                                modules))

(define find-packages-by-name
  (let ((packages (delay
                    (fold-packages (lambda (p r)
                                     (vhash-cons (package-name p) p r))
                                   vlist-null)))
        (version>? (lambda (p1 p2)
                     (version>? (package-version p1) (package-version p2)))))
    (lambda* (name #:optional version)
      "Return the list of packages with the given NAME.  If VERSION is not #f,
then only return packages whose version is prefixed by VERSION, sorted in
decreasing version order."
      (let ((matching (sort (vhash-fold* cons '() name (force packages))
                            version>?)))
        (if version
            (filter (lambda (package)
                      (version-prefix? version (package-version package)))
                    matching)
            matching)))))

(define find-newest-available-packages
  (mlambda ()
    "Return a vhash keyed by package names, and with
associated values of the form

  (newest-version newest-package ...)

where the preferred package is listed first."

    ;; FIXME: Currently, the preferred package is whichever one
    ;; was found last by 'fold-packages'.  Find a better solution.
    (fold-packages (lambda (p r)
                     (let ((name    (package-name p))
                           (version (package-version p)))
                       (match (vhash-assoc name r)
                         ((_ newest-so-far . pkgs)
                          (case (version-compare version newest-so-far)
                            ((>) (vhash-cons name `(,version ,p) r))
                            ((=) (vhash-cons name `(,version ,p ,@pkgs) r))
                            ((<) r)))
                         (#f (vhash-cons name `(,version ,p) r)))))
                   vlist-null)))

(define (find-best-packages-by-name name version)
  "If version is #f, return the list of packages named NAME with the highest
version numbers; otherwise, return the list of packages named NAME and at
VERSION."
  (if version
      (find-packages-by-name name version)
      (match (vhash-assoc name (find-newest-available-packages))
        ((_ version pkgs ...) pkgs)
        (#f '()))))


(define %sigint-prompt
  ;; The prompt to jump to upon SIGINT.
  (make-prompt-tag "interruptible"))

(define (call-with-sigint-handler thunk handler)
  "Call THUNK and return its value.  Upon SIGINT, call HANDLER with the signal
number in the context of the continuation of the call to this function, and
return its return value."
  (call-with-prompt %sigint-prompt
                    (lambda ()
                      (sigaction SIGINT
                        (lambda (signum)
                          (sigaction SIGINT SIG_DFL)
                          (abort-to-prompt %sigint-prompt signum)))
                      (dynamic-wind
                        (const #t)
                        thunk
                        (cut sigaction SIGINT SIG_DFL)))
                    (lambda (k signum)
                      (handler signum))))


;;;
;;; Package specification.
;;;

(define* (%find-package spec name version)
  (match (find-best-packages-by-name name version)
    ((pkg . pkg*)
     (unless (null? pkg*)
       (warning (G_ "ambiguous package specification `~a'~%") spec)
       (warning (G_ "choosing ~a@~a from ~a~%")
                (package-name pkg) (package-version pkg)
                (location->string (package-location pkg))))
     (match (package-superseded pkg)
       ((? package? new)
        (info (G_ "package '~a' has been superseded by '~a'~%")
              (package-name pkg) (package-name new))
        new)
       (#f
        pkg)))
    (x
     (if version
         (leave (G_ "~A: package not found for version ~a~%") name version)
         (leave (G_ "~A: unknown package~%") name)))))

(define (specification->package spec)
  "Return a package matching SPEC.  SPEC may be a package name, or a package
name followed by an at-sign and a version number.  If the version number is not
present, return the preferred newest version."
  (let-values (((name version) (package-name->name+version spec)))
    (%find-package spec name version)))

(define* (specification->package+output spec #:optional (output "out"))
  "Return the package and output specified by SPEC, or #f and #f; SPEC may
optionally contain a version number and an output name, as in these examples:

  guile
  guile@2.0.9
  guile:debug
  guile@2.0.9:debug

If SPEC does not specify a version number, return the preferred newest
version; if SPEC does not specify an output, return OUTPUT."
  (let-values (((name version sub-drv)
                (package-specification->name+version+output spec output)))
    (match (%find-package spec name version)
      (#f
       (values #f #f))
      (package
       (if (member sub-drv (package-outputs package))
           (values package sub-drv)
           (leave (G_ "package `~a' lacks output `~a'~%")
                  (package-full-name package)
                  sub-drv))))))

(define (specifications->manifest specs)
  "Given SPECS, a list of specifications such as \"emacs@25.2\" or
\"guile:debug\", return a profile manifest."
  ;; This procedure exists mostly so users of 'guix package -m' don't have to
  ;; fiddle with multiple-value returns.
  (packages->manifest
   (map (compose list specification->package+output) specs)))
