guix-devel/guix/utils.scm

562 lines
22 KiB
Scheme
Raw Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

;;; Guix --- Nix package management from Guile. -*- coding: utf-8 -*-
;;; Copyright (C) 2012 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of Guix.
;;;
;;; 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.
;;;
;;; 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 Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (guix utils)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-26)
#:use-module (srfi srfi-39)
#:use-module (srfi srfi-60)
#:use-module (rnrs bytevectors)
#:use-module ((rnrs io ports) #:select (put-bytevector))
#:use-module (ice-9 vlist)
#:use-module (ice-9 format)
#:autoload (ice-9 popen) (open-pipe*)
#:autoload (ice-9 rdelim) (read-line)
#:use-module (ice-9 regex)
#:use-module (ice-9 match)
#:autoload (system foreign) (pointer->procedure)
#:export (bytevector-quintet-length
bytevector->base32-string
bytevector->nix-base32-string
bytevector->base16-string
base32-string->bytevector
nix-base32-string->bytevector
base16-string->bytevector
sha256
%nixpkgs-directory
nixpkgs-derivation
define-record-type*
compile-time-value
memoize
gnu-triplet->nix-system
%current-system))
;;;
;;; Compile-time computations.
;;;
(define-syntax compile-time-value
(syntax-rules ()
"Evaluate the given expression at compile time. The expression must
evaluate to a simple datum."
((_ exp)
(let-syntax ((v (lambda (s)
(let ((val exp))
(syntax-case s ()
(_ #`'#,(datum->syntax s val)))))))
v))))
;;;
;;; Base 32.
;;;
(define bytevector-quintet-ref
(let* ((ref bytevector-u8-ref)
(ref+ (lambda (bv offset)
(let ((o (+ 1 offset)))
(if (>= o (bytevector-length bv))
0
(bytevector-u8-ref bv o)))))
(ref0 (lambda (bv offset)
(bit-field (ref bv offset) 3 8)))
(ref1 (lambda (bv offset)
(logior (ash (bit-field (ref bv offset) 0 3) 2)
(bit-field (ref+ bv offset) 6 8))))
(ref2 (lambda (bv offset)
(bit-field (ref bv offset) 1 6)))
(ref3 (lambda (bv offset)
(logior (ash (bit-field (ref bv offset) 0 1) 4)
(bit-field (ref+ bv offset) 4 8))))
(ref4 (lambda (bv offset)
(logior (ash (bit-field (ref bv offset) 0 4) 1)
(bit-field (ref+ bv offset) 7 8))))
(ref5 (lambda (bv offset)
(bit-field (ref bv offset) 2 7)))
(ref6 (lambda (bv offset)
(logior (ash (bit-field (ref bv offset) 0 2) 3)
(bit-field (ref+ bv offset) 5 8))))
(ref7 (lambda (bv offset)
(bit-field (ref bv offset) 0 5)))
(refs (vector ref0 ref1 ref2 ref3 ref4 ref5 ref6 ref7)))
(lambda (bv index)
"Return the INDEXth quintet of BV."
(let ((p (vector-ref refs (modulo index 8))))
(p bv (quotient (* index 5) 8))))))
(define bytevector-quintet-ref-right
(let* ((ref bytevector-u8-ref)
(ref+ (lambda (bv offset)
(let ((o (+ 1 offset)))
(if (>= o (bytevector-length bv))
0
(bytevector-u8-ref bv o)))))
(ref0 (lambda (bv offset)
(bit-field (ref bv offset) 0 5)))
(ref1 (lambda (bv offset)
(logior (bit-field (ref bv offset) 5 8)
(ash (bit-field (ref+ bv offset) 0 2) 3))))
(ref2 (lambda (bv offset)
(bit-field (ref bv offset) 2 7)))
(ref3 (lambda (bv offset)
(logior (bit-field (ref bv offset) 7 8)
(ash (bit-field (ref+ bv offset) 0 4) 1))))
(ref4 (lambda (bv offset)
(logior (bit-field (ref bv offset) 4 8)
(ash (bit-field (ref+ bv offset) 0 1) 4))))
(ref5 (lambda (bv offset)
(bit-field (ref bv offset) 1 6)))
(ref6 (lambda (bv offset)
(logior (bit-field (ref bv offset) 6 8)
(ash (bit-field (ref+ bv offset) 0 3) 2))))
(ref7 (lambda (bv offset)
(bit-field (ref bv offset) 3 8)))
(refs (vector ref0 ref1 ref2 ref3 ref4 ref5 ref6 ref7)))
(lambda (bv index)
"Return the INDEXth quintet of BV, assuming quintets start from the
least-significant bits, contrary to what RFC 4648 describes."
(let ((p (vector-ref refs (modulo index 8))))
(p bv (quotient (* index 5) 8))))))
(define (bytevector-quintet-length bv)
"Return the number of quintets (including truncated ones) available in BV."
(ceiling (/ (* (bytevector-length bv) 8) 5)))
(define (bytevector-quintet-fold proc init bv)
"Return the result of applying PROC to each quintet of BV and the result of
the previous application or INIT."
(define len
(bytevector-quintet-length bv))
(let loop ((i 0)
(r init))
(if (= i len)
r
(loop (1+ i) (proc (bytevector-quintet-ref bv i) r)))))
(define (bytevector-quintet-fold-right proc init bv)
"Return the result of applying PROC to each quintet of BV and the result of
the previous application or INIT."
(define len
(bytevector-quintet-length bv))
(let loop ((i len)
(r init))
(if (zero? i)
r
(let ((j (- i 1)))
(loop j (proc (bytevector-quintet-ref-right bv j) r))))))
(define (make-bytevector->base32-string quintet-fold base32-chars)
(lambda (bv)
"Return a base32 encoding of BV using BASE32-CHARS as the alphabet."
(let ((chars (quintet-fold (lambda (q r)
(cons (vector-ref base32-chars q)
r))
'()
bv)))
(list->string (reverse chars)))))
(define %nix-base32-chars
;; See `libutil/hash.cc'.
#(#\0 #\1 #\2 #\3 #\4 #\5 #\6 #\7 #\8 #\9
#\a #\b #\c #\d #\f #\g #\h #\i #\j #\k #\l #\m #\n
#\p #\q #\r #\s #\v #\w #\x #\y #\z))
(define %rfc4648-base32-chars
#(#\a #\b #\c #\d #\e #\f #\g #\h #\i #\j #\k #\l #\m
#\n #\o #\p #\q #\r #\s #\t #\u #\v #\w #\x #\y #\z
#\2 #\3 #\4 #\5 #\6 #\7))
(define bytevector->base32-string
(make-bytevector->base32-string bytevector-quintet-fold
%rfc4648-base32-chars))
(define bytevector->nix-base32-string
(make-bytevector->base32-string bytevector-quintet-fold-right
%nix-base32-chars))
(define bytevector-quintet-set!
(let* ((setq! (lambda (bv offset start stop value)
(let ((v (bytevector-u8-ref bv offset))
(w (arithmetic-shift value start))
(m (bitwise-xor (1- (expt 2 stop))
(1- (expt 2 start)))))
(bytevector-u8-set! bv offset
(bitwise-merge m w v)))))
(set0! (lambda (bv offset value)
(setq! bv offset 3 8 value)))
(set1! (lambda (bv offset value)
(setq! bv offset 0 3 (bit-field value 2 5))
(or (= (+ 1 offset) (bytevector-length bv))
(setq! bv (+ 1 offset) 6 8 (bit-field value 0 2)))))
(set2! (lambda (bv offset value)
(setq! bv offset 1 6 value)))
(set3! (lambda (bv offset value)
(setq! bv offset 0 1 (bit-field value 4 5))
(or (= (+ 1 offset) (bytevector-length bv))
(setq! bv (+ 1 offset) 4 8 (bit-field value 0 4)))))
(set4! (lambda (bv offset value)
(setq! bv offset 0 4 (bit-field value 1 5))
(or (= (+ 1 offset) (bytevector-length bv))
(setq! bv (+ 1 offset) 7 8 (bit-field value 0 1)))))
(set5! (lambda (bv offset value)
(setq! bv offset 2 7 value)))
(set6! (lambda (bv offset value)
(setq! bv offset 0 2 (bit-field value 3 5))
(or (= (+ 1 offset) (bytevector-length bv))
(setq! bv (+ 1 offset) 5 8 (bit-field value 0 3)))))
(set7! (lambda (bv offset value)
(setq! bv offset 0 5 value)))
(sets (vector set0! set1! set2! set3! set4! set5! set6! set7!)))
(lambda (bv index value)
"Set the INDEXth quintet of BV to VALUE."
(let ((p (vector-ref sets (modulo index 8))))
(p bv (quotient (* index 5) 8) (logand value #x1f))))))
(define bytevector-quintet-set-right!
(let* ((setq! (lambda (bv offset start stop value)
(let ((v (bytevector-u8-ref bv offset))
(w (arithmetic-shift value start))
(m (bitwise-xor (1- (expt 2 stop))
(1- (expt 2 start)))))
(bytevector-u8-set! bv offset
(bitwise-merge m w v)))))
(set0! (lambda (bv offset value)
(setq! bv offset 0 5 value)))
(set1! (lambda (bv offset value)
(setq! bv offset 5 8 (bit-field value 0 3))
(or (= (+ 1 offset) (bytevector-length bv))
(setq! bv (+ 1 offset) 0 2 (bit-field value 3 5)))))
(set2! (lambda (bv offset value)
(setq! bv offset 2 7 value)))
(set3! (lambda (bv offset value)
(setq! bv offset 7 8 (bit-field value 0 1))
(or (= (+ 1 offset) (bytevector-length bv))
(setq! bv (+ 1 offset) 0 4 (bit-field value 1 5)))))
(set4! (lambda (bv offset value)
(setq! bv offset 4 8 (bit-field value 0 4))
(or (= (+ 1 offset) (bytevector-length bv))
(setq! bv (+ 1 offset) 0 1 (bit-field value 4 5)))))
(set5! (lambda (bv offset value)
(setq! bv offset 1 6 value)))
(set6! (lambda (bv offset value)
(setq! bv offset 6 8 (bit-field value 0 2))
(or (= (+ 1 offset) (bytevector-length bv))
(setq! bv (+ 1 offset) 0 3 (bit-field value 2 5)))))
(set7! (lambda (bv offset value)
(setq! bv offset 3 8 value)))
(sets (vector set0! set1! set2! set3! set4! set5! set6! set7!)))
(lambda (bv index value)
"Set the INDEXth quintet of BV to VALUE, assuming quintets start from
the least-significant bits."
(let ((p (vector-ref sets (modulo index 8))))
(p bv (quotient (* index 5) 8) (logand value #x1f))))))
(define (base32-string-unfold f s)
"Given procedure F which, when applied to a character, returns the
corresponding quintet, return the bytevector corresponding to string S."
(define len (string-length s))
(let ((bv (make-bytevector (quotient (* len 5) 8))))
(string-fold (lambda (chr index)
(bytevector-quintet-set! bv index (f chr))
(+ 1 index))
0
s)
bv))
(define (base32-string-unfold-right f s)
"Given procedure F which, when applied to a character, returns the
corresponding quintet, return the bytevector corresponding to string S,
starting from the right of S."
(define len (string-length s))
(let ((bv (make-bytevector (quotient (* len 5) 8))))
(string-fold-right (lambda (chr index)
(bytevector-quintet-set-right! bv index (f chr))
(+ 1 index))
0
s)
bv))
(define (make-base32-string->bytevector base32-string-unfold base32-chars)
(let ((char->value (let loop ((i 0)
(v vlist-null))
(if (= i (vector-length base32-chars))
v
(loop (+ 1 i)
(vhash-consv (vector-ref base32-chars i)
i v))))))
(lambda (s)
"Return the binary representation of base32 string S as a bytevector."
(base32-string-unfold (lambda (chr)
(or (and=> (vhash-assv chr char->value) cdr)
(error "invalid base32 character" chr)))
s))))
(define base32-string->bytevector
(make-base32-string->bytevector base32-string-unfold %rfc4648-base32-chars))
(define nix-base32-string->bytevector
(make-base32-string->bytevector base32-string-unfold-right %nix-base32-chars))
;;;
;;; Base 16.
;;;
(define (bytevector->base16-string bv)
"Return the hexadecimal representation of BV's contents."
(define len
(bytevector-length bv))
(let-syntax ((base16-chars (lambda (s)
(syntax-case s ()
(_
(let ((v (list->vector
(unfold (cut > <> 255)
(lambda (n)
(format #f "~2,'0x" n))
1+
0))))
v))))))
(define chars base16-chars)
(let loop ((i 0)
(r '()))
(if (= i len)
(string-concatenate-reverse r)
(loop (+ 1 i)
(cons (vector-ref chars (bytevector-u8-ref bv i)) r))))))
(define base16-string->bytevector
(let ((chars->value (fold (lambda (i r)
(vhash-consv (string-ref (number->string i 16)
0)
i r))
vlist-null
(iota 16))))
(lambda (s)
"Return the bytevector whose hexadecimal representation is string S."
(define bv
(make-bytevector (quotient (string-length s) 2) 0))
(string-fold (lambda (chr i)
(let ((j (quotient i 2))
(v (and=> (vhash-assv chr chars->value) cdr)))
(if v
(if (zero? (logand i 1))
(bytevector-u8-set! bv j
(arithmetic-shift v 4))
(let ((w (bytevector-u8-ref bv j)))
(bytevector-u8-set! bv j (logior v w))))
(error "invalid hexadecimal character" chr)))
(+ i 1))
0
s)
bv)))
;;;
;;; Hash.
;;;
(define sha256
(cond
((compile-time-value
(false-if-exception (dynamic-link "libgcrypt")))
;; Using libgcrypt.
(let ((hash (pointer->procedure void
(dynamic-func "gcry_md_hash_buffer"
(dynamic-link "libgcrypt"))
`(,int * * ,size_t)))
(sha256 8)) ; GCRY_MD_SHA256, as of 1.5.0
(lambda (bv)
"Return the SHA256 of BV as a bytevector."
(let ((digest (make-bytevector (/ 256 8))))
(hash sha256 (bytevector->pointer digest)
(bytevector->pointer bv) (bytevector-length bv))
digest))))
((compile-time-value
(false-if-exception (resolve-interface '(chop hash))))
;; Using libchop.
(let ((bytevector-hash (@ (chop hash) bytevector-hash))
(hash-method/sha256 (@ (chop hash) hash-method/sha256)))
(lambda (bv)
"Return the SHA256 of BV as a bytevector."
(bytevector-hash hash-method/sha256 bv))))
(else
;; Slow, poor programmer's implementation that uses Coreutils.
(lambda (bv)
"Return the SHA256 of BV as a bytevector."
(let ((in (pipe))
(out (pipe))
(pid (primitive-fork)))
(if (= 0 pid)
(begin ; child
(close (cdr in))
(close (car out))
(close 0)
(close 1)
(dup2 (fileno (car in)) 0)
(dup2 (fileno (cdr out)) 1)
(execlp "sha256sum" "sha256sum"))
(begin ; parent
(close (car in))
(close (cdr out))
(put-bytevector (cdr in) bv)
(close (cdr in)) ; EOF
(let ((line (car (string-tokenize (read-line (car out))))))
(close (car out))
(and (and=> (status:exit-val (cdr (waitpid pid)))
zero?)
(base16-string->bytevector line))))))))))
;;;
;;; Nixpkgs.
;;;
(define %nixpkgs-directory
(make-parameter
;; Capture the build-time value of $NIXPKGS.
(compile-time-value (getenv "NIXPKGS"))))
(define (nixpkgs-derivation attribute)
"Return the derivation path of ATTRIBUTE in Nixpkgs."
(let* ((p (open-pipe* OPEN_READ "nix-instantiate" "-A"
attribute (%nixpkgs-directory)))
(l (read-line p))
(s (close-pipe p)))
(and (zero? (status:exit-val s))
(not (eof-object? l))
l)))
;;;
;;; Miscellaneous.
;;;
(define-syntax define-record-type*
(lambda (s)
"Define the given record type such that an additional \"syntactic
constructor\" is defined, which allows instances to be constructed with named
field initializers, à la SRFI-35, as well as default values."
(define (make-syntactic-constructor name ctor fields defaults)
"Make the syntactic constructor NAME that calls CTOR, and expects all
of FIELDS to be initialized. DEFAULTS is the list of FIELD/DEFAULT-VALUE
tuples."
(with-syntax ((name name)
(ctor ctor)
(expected fields)
(defaults defaults))
#'(define-syntax name
(lambda (s)
(syntax-case s expected
((_ (field value) (... ...))
(let ((fields (map syntax->datum #'(field (... ...))))
(inits (map (match-lambda
((f v)
(list (syntax->datum f) v)))
#'((field value) (... ...))))
(dflt (map (match-lambda
((f v)
(list (syntax->datum f) v)))
#'defaults)))
(define (field-value f)
(match (assoc f inits)
((_ v) v)
(#f (car (assoc-ref dflt f)))))
(if (lset= eq? (append fields (map car dflt))
'expected)
#`(ctor #,@(map field-value 'expected))
(error "missing or extraneous field initializers"
(lset-difference eq? fields 'expected))))))))))
(define (field-default-value s)
(syntax-case s (default)
((field (default val) _ ...)
(list #'field #'val))
((field _ options ...)
(field-default-value #'(field options ...)))
(_ #f)))
(syntax-case s ()
((_ type syntactic-ctor ctor pred
(field get options ...) ...)
#`(begin
(define-record-type type
(ctor field ...)
pred
(field get) ...)
#,(make-syntactic-constructor #'syntactic-ctor #'ctor
#'(field ...)
(filter-map field-default-value
#'((field options ...)
...))))))))
(define (memoize proc)
"Return a memoizing version of PROC."
(let ((cache (make-hash-table)))
(lambda args
(let ((results (hash-ref cache args)))
(if results
(apply values results)
(let ((results (call-with-values (lambda ()
(apply proc args))
list)))
(hash-set! cache args results)
(apply values results)))))))
(define (gnu-triplet->nix-system triplet)
"Return the Nix system type corresponding to TRIPLET, a GNU triplet as
returned by `config.guess'."
(let ((triplet (cond ((string-match "^i[345]86-(.*)$" triplet)
=>
(lambda (m)
(string-append "i686-" (match:substring m 1))))
(else triplet))))
(cond ((string-match "^([^-]+)-([^-]+-)?linux-gnu.*" triplet)
=>
(lambda (m)
;; Nix omits `-gnu' for GNU/Linux.
(string-append (match:substring m 1) "-linux")))
((string-match "^([^-]+)-([^-]+-)?([[:alpha:]]+)([0-9]+\\.?)*$" triplet)
=>
(lambda (m)
;; Nix strip the version number from names such as `gnu0.3',
;; `darwin10.2.0', etc., and always strips the vendor part.
(string-append (match:substring m 1) "-"
(match:substring m 3))))
(else triplet))))
(define %current-system
;; System type as expected by Nix, usually ARCHITECTURE-KERNEL.
(make-parameter (gnu-triplet->nix-system %host-type)))