aboutsummaryrefslogtreecommitdiff
path: root/guix/snix.scm
blob: a5b8447470e843624d6a2789d1f902cad0b4cba5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
;;; Guix --- Nix package management from Guile.         -*- coding: utf-8 -*-
;;; Copyright (C) 2010, 2011, 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 snix)
  #:use-module (sxml ssax)
  #:use-module (ice-9 popen)
  #:use-module (ice-9 match)
  #:use-module (ice-9 rdelim)
  #:use-module (ice-9 format)
  #:use-module (ice-9 regex)
  #:use-module (ice-9 vlist)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-9)
  #:use-module (srfi srfi-11)
  #:use-module (srfi srfi-26)
  #:use-module (srfi srfi-37)
  #:use-module (system foreign)
  #:use-module (rnrs bytevectors)
  #:use-module (guix utils)
  #:use-module (guix base32)
  #:use-module (guix config)
  #:export (open-nixpkgs
            xml->snix
            nixpkgs->guix-package))

;;; Commentary:
;;;
;;; Converting Nix code to s-expressions, and then to Guix `package'
;;; declarations, using the XML output of `nix-instantiate'.
;;;
;;; Code:


;;;
;;; SNix.
;;;

;; Nix object types visible in the XML output of `nix-instantiate' and
;; mapping to S-expressions (we map to sexps, not records, so that we
;; can do pattern matching):
;;
;;   at               (at varpat attrspat)
;;   attr             (attribute loc name value)
;;   attrs            (attribute-set attributes)
;;   attrspat         (attribute-set-pattern patterns)
;;   bool             #f|#t
;;   derivation       (derivation drv-path out-path attributes)
;;   ellipsis         '...
;;   expr             (snix loc body ...)
;;   function         (function loc at|attrspat|varpat)
;;   int              int
;;   list             list
;;   null             'null
;;   path             string
;;   string           string
;;   unevaluated      'unevaluated
;;   varpat           (varpat name)
;;
;; Initially ATTRIBUTES in `derivation' and `attribute-set' was a promise;
;; however, handling `repeated' nodes makes it impossible to do anything
;; lazily because the whole SXML tree has to be traversed to maintain the
;; list of known derivations.

(define (xml-element->snix elem attributes body derivations)
  "Return an SNix element corresponding to XML element ELEM."

  (define (loc)
    (location (assq-ref attributes 'path)
              (assq-ref attributes 'line)
              (assq-ref attributes 'column)))

  (case elem
    ((at)
     (values `(at ,(car body) ,(cadr body)) derivations))
    ((attr)
     (let ((name (assq-ref attributes 'name)))
       (cond ((null? body)
              (values `(attribute-pattern ,name) derivations))
             ((and (pair? body) (null? (cdr body)))
              (values `(attribute ,(loc) ,name ,(car body))
                      derivations))
             (else
              (error "invalid attribute body" name (loc) body)))))
    ((attrs)
     (values `(attribute-set ,(reverse body)) derivations))
    ((attrspat)
     (values `(attribute-set-pattern ,body) derivations))
    ((bool)
     (values (string-ci=? "true" (assq-ref attributes 'value))
             derivations))
    ((derivation)
     (let ((drv-path (assq-ref attributes 'drvPath))
           (out-path (assq-ref attributes 'outPath)))
       (if (equal? body '(repeated))
           (let ((body (vhash-assoc drv-path derivations)))
             (if (pair? body)
                 (values `(derivation ,drv-path ,out-path ,(cdr body))
                         derivations)

                 ;; DRV-PATH hasn't been encountered yet but may be later
                 ;; (see <http://article.gmane.org/gmane.linux.distributions.nixos/5946>.)
                 ;; Return an `unresolved' node.
                 (values `(unresolved
                           ,(lambda (derivations)
                              (let ((body (vhash-assoc drv-path derivations)))
                                (if (pair? body)
                                    `(derivation ,drv-path ,out-path
                                                 ,(cdr body))
                                    (error "no previous occurrence of derivation"
                                           drv-path)))))
                         derivations)))
           (values `(derivation ,drv-path ,out-path ,body)
                   (vhash-cons drv-path body derivations)))))
    ((ellipsis)
     (values '... derivations))
    ((expr)
     (values `(snix ,(loc) ,@body) derivations))
    ((function)
     (values `(function ,(loc) ,body) derivations))
    ((int)
     (values (string->number (assq-ref attributes 'value))
             derivations))
    ((list)
     (values body derivations))
    ((null)
     (values 'null derivations))
    ((path)
     (values (assq-ref attributes 'value) derivations))
    ((repeated)
     (values 'repeated derivations))
    ((string)
     (values (assq-ref attributes 'value) derivations))
    ((unevaluated)
     (values 'unevaluated derivations))
    ((varpat)
     (values `(varpat ,(assq-ref attributes 'name)) derivations))
    (else (error "unhandled Nix XML element" elem))))

(define (resolve snix derivations)
  "Return a new SNix tree where `unresolved' nodes from SNIX have been
replaced by the result of their application to DERIVATIONS, a vhash."
  (let loop ((node snix)
             (seen vlist-null))
    (if (vhash-assq node seen)
        (values node seen)
        (match node
          (('unresolved proc)
           (let ((n (proc derivations)))
             (values n seen)))
          ((tag body ...)
           (let ((body+seen (fold (lambda (n body+seen)
                                    (call-with-values
                                        (lambda ()
                                          (loop n (cdr body+seen)))
                                      (lambda (n* seen)
                                        (cons (cons n* (car body+seen))
                                              (vhash-consq n #t seen)))))
                                  (cons '() (vhash-consq node #t seen))
                                  body)))
             (values (cons tag (reverse (car body+seen)))
                     (vhash-consq node #t (cdr body+seen)))))
          (anything
           (values anything seen))))))

(define xml->snix
  (let ((parse
         (ssax:make-parser NEW-LEVEL-SEED
                           (lambda (elem-gi attributes namespaces expected-content
                                    seed)
                             (cons '() (cdr seed)))

                           FINISH-ELEMENT
                           (lambda (elem-gi attributes namespaces parent-seed
                                            seed)
                             (let ((snix        (car seed))
                                   (derivations (cdr seed)))
                               (let-values (((snix derivations)
                                             (xml-element->snix elem-gi
                                                                attributes
                                                                snix
                                                                derivations)))
                                 (cons (cons snix (car parent-seed))
                                       derivations))))

                           CHAR-DATA-HANDLER
                           (lambda (string1 string2 seed)
                             ;; Discard inter-node strings, which are blanks.
                             seed))))
    (lambda (port)
      "Return the SNix represention of TREE, an SXML tree as returned by
parsing the XML output of `nix-instantiate' on Nixpkgs."
      (match (parse port (cons '() vlist-null))
        (((snix) . derivations)
         (resolve snix derivations))))))

(define (attribute-value attribute)
  "Return the value of ATTRIBUTE."
  (match attribute
    (('attribute _ _ value) value)))

(define (derivation-source derivation)
  "Return the \"src\" attribute of DERIVATION or #f if not found."
  (match derivation
    (('derivation _ _ (attributes ...))
     (find-attribute-by-name "src" attributes))))

(define (derivation-output-path derivation)
  "Return the output path of DERIVATION."
  (match derivation
    (('derivation _ out-path _)
     out-path)
    (_ #f)))

(define (source-output-path src)
  "Return the output path of SRC, the \"src\" attribute of a derivation."
  (derivation-output-path (attribute-value src)))

(define (source-urls src)
  "Return the URLs of SRC, the \"src\" attribute of a derivation."
  (match src
    (('attribute _ _ ('derivation _ _ (attributes ...)))
     (match (find-attribute-by-name "urls" attributes)
       (('attribute _ _ value)
        value)))
    (_ #f)))

(define (source-sha256 src)
  "Return the sha256 of SRC, the \"src\" attribute of a derivation, as a
bytevector."
  (match src
    (('attribute _ _ ('derivation _ _ (attributes ...)))
     (match (find-attribute-by-name "outputHash" attributes)
       (('attribute _ _ value)
        (match value
          ((= string-length 52)
           (nix-base32-string->bytevector value))
          ((= string-length 64)
           (base16-string->bytevector value))
          (_
           (error "unsupported hash format" value))))))
    (_ #f)))

(define (derivation-source-output-path derivation)
  "Return the output path of the \"src\" attribute of DERIVATION or #f
if DERIVATION lacks an \"src\" attribute."
  (and=> (derivation-source derivation) source-output-path))

(define* (open-nixpkgs nixpkgs #:optional attribute)
  "Return an input pipe to the XML representation of Nixpkgs.  When
ATTRIBUTE is true, only that attribute is considered."
  (with-fluids ((%default-port-encoding "UTF-8"))
    (let ((cross-system (format #f "{
  config = \"i686-guix-linux-gnu\";
  libc = \"glibc\";
  arch = \"guix\";
  withTLS = true;
  float = \"hard\";
  openssl.system = \"linux-generic32\";
  platform = (import ~a/pkgs/top-level/platforms.nix).sheevaplug;
}" nixpkgs)))
      (apply open-pipe* OPEN_READ
             %nix-instantiate "--strict" "--eval-only" "--xml"

             ;; Pass a dummy `crossSystem' argument so that `buildInputs' and
             ;; `buildNativeInputs' are not coalesced.
             ;; XXX: This is hacky and has other problems.
             ;"--arg" "crossSystem" cross-system

             `(,@(if attribute
                     `("-A" ,attribute)
                     '())
               ,nixpkgs)))))

(define (pipe-failed? pipe)
  "Close pipe and return its status if it failed."
  (let ((status (close-pipe pipe)))
    (if (or (status:term-sig status)
            (not (= (status:exit-val status) 0)))
        status
        #f)))

(define (find-attribute-by-name name attributes)
  "Return attribute NAME in ATTRIBUTES, an attribute set or list of SNix
attributes, or #f if NAME cannot be found."
  (find (lambda (a)
          (match a
            (('attribute _ (? (cut string=? <> name)) _)
             a)
            (_ #f)))
        (match attributes
          (('attribute-set (attributes ...))
           attributes)
          (_
           attributes))))

(define (package-source-output-path package)
  "Return the output path of the \"src\" derivation of PACKAGE."
  (derivation-source-output-path (attribute-value package)))


;;;
;;; Conversion of "Nix expressions" to "Guix expressions".
;;;

(define (factorize-uri uri version)
  "Factorize URI, a package tarball URI as a string, such that any occurrences
of the string VERSION is replaced by the symbol 'version."
  (let ((version-rx (make-regexp (regexp-quote version))))
    (match (regexp-exec version-rx uri)
      (#f
       uri)
      (_
       (let ((indices (fold-matches version-rx uri
                                    '((0))
                                    (lambda (m result)
                                      (match result
                                        (((start) rest ...)
                                         `((,(match:end m))
                                           (,start . ,(match:start m))
                                           ,@rest)))))))
         (fold (lambda (index result)
                 (match index
                   ((start)
                    (cons (substring uri start)
                          result))
                   ((start . end)
                    (cons* (substring uri start end)
                           'version
                           result))))
               '()
               indices))))))

(define (snix-derivation->guix-package derivation)
  "Return the `package' s-expression corresponding to SNix DERIVATION, a
Nixpkgs `stdenv.mkDerivation'-style derivation, and the original source
location of DERIVATION."
  (match derivation
    (('derivation _ _ (attributes ...))
     (let*-values (((full-name loc)
                    (match (find-attribute-by-name "name" attributes)
                      (('attribute loc _ value)
                       (values value loc))
                      (_
                       (values #f #f))))
                   ((name version)
                    (package-name->name+version full-name)))
       (define (convert-inputs type)
         ;; Convert the derivation's input from a list of SNix derivations to
         ;; a list of name/variable pairs.
         (match (and=> (find-attribute-by-name type attributes)
                       attribute-value)
           (#f
            '())
           ((('derivation _ _ (attributes ...)) ...)
            (map (lambda (attrs)
                   (let* ((full-name (attribute-value
                                      (find-attribute-by-name "name" attrs)))
                          (name      (package-name->name+version full-name)))
                     (list name
                           (list 'unquote
                                 (string->symbol name)))))
                 attributes))))

       (define (maybe-inputs guix-name inputs)
         (match inputs
           (()
            '())
           ((inputs ...)
            (list (list guix-name
                        (list 'quasiquote inputs))))))

       (define (pretty-uri uri version)
         (match (factorize-uri uri version)
           ((items ...)
            `(string-append ,@items))
           (x x)))

       (let* ((source  (find-attribute-by-name "src" attributes))
              (urls    (source-urls source))
              (sha256  (source-sha256 source))
              (meta    (and=> (find-attribute-by-name "meta" attributes)
                              attribute-value)))
         (values
          `(package
             (name ,name)
             (version ,version)
             (source (origin
                      (method url-fetch)
                      (uri ,(pretty-uri (car urls) version))
                      (sha256
                       (base32
                        ,(bytevector->nix-base32-string sha256)))))
             (build-system gnu-build-system)

             ;; When doing a native Nixpkgs build, `buildInputs' is empty and
             ;; everything is in `buildNativeInputs'.  So we can't distinguish
             ;; between both, here.
             ,@(maybe-inputs 'inputs
                             (convert-inputs "buildNativeInputs"))
             ,@(maybe-inputs 'propagated-inputs
                             (convert-inputs "propagatedBuildNativeInputs"))

             (home-page ,(and=> (find-attribute-by-name "homepage" meta)
                                attribute-value))
             (synopsis ,(and=> (find-attribute-by-name "description" meta)
                               attribute-value))
             (description
              ,(and=> (find-attribute-by-name "longDescription" meta)
                      attribute-value))
             (license ,(and=> (find-attribute-by-name "license" meta)
                              attribute-value)))
          loc))))))

(define (nixpkgs->guix-package nixpkgs attribute)
  "Evaluate ATTRIBUTE in NIXPKGS, the file name of a Nixpkgs checkout,
and return the `package' s-expression corresponding to that package."
  (let ((port (open-nixpkgs nixpkgs attribute)))
    (match (xml->snix port)
      (('snix loc (and drv ('derivation _ ...)))
       (and (not (pipe-failed? port))
            (snix-derivation->guix-package drv)))
      (_
       (not (pipe-failed? port))))))

;;; snix.scm ends here