;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2022 Maxime Devos <maximedevos@telenet.be>
;;; Copyright © 2022 Olivier Dion <olivier.dion@polymtl.ca>
;;;
;;; 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 build absolute-inclusions)
  #:use-module (guix build utils)
  #:use-module (ice-9 match)
  #:use-module (rnrs exceptions)
  #:export (absolute-inclusions patch-header-inclusions))

(define (excluded-input? input)
  ;; Exclude glibc to avoid increasing the closure size when a
  ;; static library + binary is build.  Likewise, exclude
  ;; linux-libre-headers.
  (match input
    ((_ . store-item)
     (or (file-exists? (string-append store-item "/include/stdlib.h"))
         (directory-exists? (string-append store-item "/include/linux"))))))

(define (absolute-inclusions files header-locations)
  (substitute* files
    (("^[ \t]*#[ \t]*include[ \t]*<(.*)>[ \t]*" original header-name)
     (guard (c ((search-error? c) original))
       (format #f "#include <~a>"
               (pk 'foo (search-input-file header-locations
                (string-append "include/" header-name))))))))

(define header-file?
  ;; See gcc(1) for the list of suffixes.
  (let ((suffixes (list "h" "hh" "H" "hp" "hxx" "hpp" "HPP" "h++" "tcc")))
    (file-name-predicate
     (format #f "\\.(~a)$" (string-join suffixes "|" 'infix)))))

(define* (patch-header-inclusions #:key inputs outputs #:allow-other-keys)
  "Patch inclusions in C headers in OUTPUTS to use absolute file names."
  (define header-locations
    (filter (negate excluded-input?) (append outputs inputs)))
  (for-each (match-lambda
              ((_ . output)
               (absolute-inclusions
                (find-files (string-append output "/include")
                            header-file?)
                header-locations)))
            outputs))