import: Factorize utility functions.

* guix/import/pypi.scm (hash-table->alist, flatten, assoc-ref*,
  url-fetch, json-fetch): Pull procedures from here into...
* guix/import/utils.scm: Here and...
* guix/import/json.scm: Here.  New file.
* Makefile.am (MODULE)[HAVE_GUILE_JSON]: Add it.
* guix/import/gnu.scm (file-sha256): Move from here to...
* guix/hash.scm: Here.
* tests/pypi.scm (pypi->guix-package): Update mock module reference.

Makefile.am

@@ -174,6 +174,7 @@ SCM_TESTS =					\
 if HAVE_GUILE_JSON
 
 MODULES +=					\
+  guix/import/json.scm				\
   guix/import/pypi.scm				\
   guix/scripts/import/pypi.scm
 

guix/hash.scm

@@ -26,6 +26,7 @@
   #:export (sha256
             open-sha256-port
             port-sha256
+            file-sha256
             open-sha256-input-port))
 
 ;;; Commentary:
@@ -129,6 +130,10 @@ output port."
     (close-port out)
     (get)))
 
+(define (file-sha256 file)
+  "Return the SHA256 hash (a bytevector) of FILE."
+  (call-with-input-file file port-sha256))
+
 (define (open-sha256-input-port port)
   "Return an input port that wraps PORT and a thunk to get the hash of all the
 data read from PORT.  The thunk always returns the same value."

guix/import/gnu.scm

@@ -18,6 +18,7 @@
 
 (define-module (guix import gnu)
   #:use-module (guix gnu-maintenance)
+  #:use-module (guix import utils)
   #:use-module (guix utils)
   #:use-module (guix store)
   #:use-module (guix hash)
@@ -38,10 +39,6 @@
 ;;;
 ;;; Code:
 
-(define (file-sha256 file)
-  "Return the SHA256 hash of FILE as a bytevector."
-  (call-with-input-file file port-sha256))
-
 (define (qualified-url url)
   "Return a fully-qualified URL based on URL."
   (if (string-prefix? "/" url)

guix/import/json.scm

@@ -0,0 +1,32 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2014 David Thompson <davet@gnu.org>
+;;; Copyright © 2015 Eric Bavier <bavier@member.fsf.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 (guix import json)
+  #:use-module (json)
+  #:use-module (guix utils)
+  #:use-module (guix import utils)
+  #:export (json-fetch))
+
+(define (json-fetch url)
+  "Return an alist representation of the JSON resource URL, or #f on failure."
+  (call-with-temporary-output-file
+   (lambda (temp port)
+     (and (url-fetch url temp)
+          (hash-table->alist
+           (call-with-input-file temp json->scm))))))

guix/import/pypi.scm

@@ -27,40 +27,15 @@
   #:use-module (web uri)
   #:use-module (guix utils)
   #:use-module (guix import utils)
+  #:use-module (guix import json)
   #:use-module (guix base32)
   #:use-module (guix hash)
   #:use-module (guix packages)
   #:use-module (guix licenses)
   #:use-module (guix build-system python)
-  #:use-module ((guix build download) #:prefix build:)
   #:use-module (gnu packages python)
   #:export (pypi->guix-package))
 
-(define (hash-table->alist table)
-  "Return an alist represenation of TABLE."
-  (map (match-lambda
-        ((key . (lst ...))
-         (cons key
-               (map (lambda (x)
-                      (if (hash-table? x)
-                          (hash-table->alist x)
-                          x))
-                    lst)))
-        ((key . (? hash-table? table))
-         (cons key (hash-table->alist table)))
-        (pair pair))
-       (hash-map->list cons table)))
-
-(define (flatten lst)
-  "Return a list that recursively concatenates all sub-lists of LIST."
-  (fold-right
-   (match-lambda*
-    (((sub-list ...) memo)
-     (append (flatten sub-list) memo))
-    ((elem memo)
-     (cons elem memo)))
-   '() lst))
-
 (define (join lst delimiter)
   "Return a list that contains the elements of LST, each separated by
 DELIMETER."
@@ -71,13 +46,6 @@ DELIMETER."
     ((elem . rest)
      (cons* elem delimiter (join rest delimiter)))))
 
-(define (assoc-ref* alist key . rest)
-  "Return the value for KEY from ALIST.  For each additional key specified,
-recursively apply the procedure to the sub-list."
-  (if (null? rest)
-      (assoc-ref alist key)
-      (apply assoc-ref* (assoc-ref alist key) rest)))
-
 (define string->license
   (match-lambda
    ("GNU LGPL" lgpl2.0)
@@ -88,19 +56,6 @@ recursively apply the procedure to the sub-list."
    ("Apache License, Version 2.0" asl2.0)
    (_ #f)))
 
-(define (url-fetch url file-name)
-  "Save the contents of URL to FILE-NAME.  Return #f on failure."
-  (parameterize ((current-output-port (current-error-port)))
-    (build:url-fetch url file-name)))
-
-(define (json-fetch url)
-  "Return an alist representation of the JSON resource URL, or #f on failure."
-  (call-with-temporary-output-file
-   (lambda (temp port)
-     (and (url-fetch url temp)
-          (hash-table->alist
-           (call-with-input-file temp json->scm))))))
-
 (define (pypi-fetch name)
   "Return an alist representation of the PyPI metadata for the package NAME,
 or #f on failure."

guix/import/utils.scm

@@ -20,7 +20,16 @@
   #:use-module (ice-9 match)
   #:use-module (ice-9 regex)
   #:use-module (srfi srfi-1)
-  #:export (factorize-uri))
+  #:use-module (guix hash)
+  #:use-module (guix utils)
+  #:use-module ((guix build download) #:prefix build:)
+  #:export (factorize-uri
+
+            hash-table->alist
+            flatten
+            assoc-ref*
+
+            url-fetch))
 
 (define (factorize-uri uri version)
   "Factorize URI, a package tarball URI as a string, such that any occurrences
@@ -49,3 +58,40 @@ of the string VERSION is replaced by the symbol 'version."
                            result))))
                '()
                indices))))))
+
+(define (hash-table->alist table)
+  "Return an alist represenation of TABLE."
+  (map (match-lambda
+        ((key . (lst ...))
+         (cons key
+               (map (lambda (x)
+                      (if (hash-table? x)
+                          (hash-table->alist x)
+                          x))
+                    lst)))
+        ((key . (? hash-table? table))
+         (cons key (hash-table->alist table)))
+        (pair pair))
+       (hash-map->list cons table)))
+
+(define (flatten lst)
+  "Return a list that recursively concatenates all sub-lists of LST."
+  (fold-right
+   (match-lambda*
+    (((sub-list ...) memo)
+     (append (flatten sub-list) memo))
+    ((elem memo)
+     (cons elem memo)))
+   '() lst))
+
+(define (assoc-ref* alist key . rest)
+  "Return the value for KEY from ALIST.  For each additional key specified,
+recursively apply the procedure to the sub-list."
+  (if (null? rest)
+      (assoc-ref alist key)
+      (apply assoc-ref* (assoc-ref alist key) rest)))
+
+(define (url-fetch url file-name)
+  "Save the contents of URL to FILE-NAME.  Return #f on failure."
+  (parameterize ((current-output-port (current-error-port)))
+    (build:url-fetch url file-name)))

tests/pypi.scm

@@ -60,7 +60,7 @@
 
 (test-assert "pypi->guix-package"
   ;; Replace network resources with sample data.
-  (mock ((guix import pypi) url-fetch
+  (mock ((guix import utils) url-fetch
          (lambda (url file-name)
            (with-output-to-file file-name
              (lambda ()