; Copyright (C) 2021 Apple Inc. All rights reserved.
;
; Redistribution and use in source and binary forms, with or without
; modification, are permitted provided that the following conditions
; are met:
; 1. Redistributions of source code must retain the above copyright
;    notice, this list of conditions and the following disclaimer.
; 2. Redistributions in binary form must reproduce the above copyright
;    notice, this list of conditions and the following disclaimer in the
;    documentation and/or other materials provided with the distribution.
;
; THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
; THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
; PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
; BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
; CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
; SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
; INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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; ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
; THE POSSIBILITY OF SUCH DAMAGE.

(macro (define-once form)
  (let* ((ps (cdr form))
         (signature (car ps))
         (body (cdr ps))
         (name (car signature)))
    (if (not (defined? name))
        `(define ,signature ,@body))))

(define-once (home-literal . relative-subpaths)
  (apply literal (map home-relative-path relative-subpaths)))

(define-once (home-subpath . relative-subpaths)
  (apply subpath (map home-relative-path relative-subpaths)))

(define-once (home-prefix . relative-subpaths)
  (apply prefix (map home-relative-path relative-subpaths)))

(define-once (home-regex . relative-regexes)
  (require-all
    (apply any-home-regex relative-regexes)
    (home-subpath "")))

(define-once (home-relative-path relative-subpath)
  (string-append "${HOME}" relative-subpath))

(define-once (front-user-home-subpath . relative-subpaths)
  (apply subpath (map front-user-home-relative-path relative-subpaths)))

(define-once (front-user-home-relative-path relative-subpath)
  (string-append "${FRONT_USER_HOME}" relative-subpath))

(define-once (%elevated-precedence-finalize)
    (lambda () #f))

(macro (with-elevated-precedence form)
    (let* ((rules (cdr form)))
        ;; Later rules override earlier rules so emit the given rules as
        ;; late as possible to give them high precendence.
        `(%at-elevated-precedence-finalize (lambda () ,@rules))))

(define-once (%at-elevated-precedence-finalize func)
    (let*
        ((orig-finalize %elevated-precedence-finalize)
         (new-finalize
             (lambda ()
                 (orig-finalize)
                 (func))))
        (set! %elevated-precedence-finalize new-finalize)))

(define-once (well-known-system-group-container-path relative-subpath)
  (string-append "/private/var/containers/Shared/SystemGroup" relative-subpath))

(define-once (well-known-system-group-container-literal . relative-subpaths)
  (apply literal (map well-known-system-group-container-path relative-subpaths)))

(define-once (well-known-system-group-container-subpath . relative-subpaths)
  (apply subpath (map well-known-system-group-container-path relative-subpaths)))

(define-once (allow-well-known-system-group-container-subpath-read . subpaths)
  (for-each
    (lambda (relative-path)
      (allow file-read*
             (well-known-system-group-container-subpath relative-path)))
      subpaths))

(define-once (allow-well-known-system-group-container-literal-read . subpaths)
  (for-each
    (lambda (relative-path)
      (allow file-read*
             (well-known-system-group-container-literal relative-path)))
      subpaths))