import: Add importer for rust crates.

* guix/import/crate.scm: New file.
* guix/scripts/import/crate.scm: New file.
* guix/scripts/import.scm (importers): Add crate importer.
* tests/crate.scm: New file.
* doc/guix.texi: Add crate importer to table.
* Makefile.am (MODULES, SCM_TESTS): Add files.

7 files changed, 332 insertions, 2 deletions

diff --git a/Makefile.am b/Makefile.am
index 5cb4261f4b..84ff6642a2 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -122,6 +122,7 @@ MODULES =					\
   guix/import/snix.scm				\
   guix/import/cabal.scm				\
   guix/import/cran.scm				\
+  guix/import/crate.scm				\
   guix/import/hackage.scm			\
   guix/import/elpa.scm   			\
   guix/scripts.scm				\
@@ -141,6 +142,7 @@ MODULES =					\
   guix/scripts/lint.scm				\
   guix/scripts/challenge.scm			\
   guix/scripts/import/cran.scm			\
+  guix/scripts/import/crate.scm			\
   guix/scripts/import/gnu.scm			\
   guix/scripts/import/nix.scm			\
   guix/scripts/import/hackage.scm		\
@@ -282,7 +284,8 @@ if HAVE_GUILE_JSON
 SCM_TESTS += 					\
   tests/pypi.scm				\
   tests/cpan.scm				\
-  tests/gem.scm
+  tests/gem.scm					\
+  tests/crate.scm
 
 endif
 
diff --git a/doc/guix.texi b/doc/guix.texi
index f1c5963f76..5db20ecdfa 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -5267,6 +5267,11 @@ signatures,, emacs, The GNU Emacs Manual}).
 identifier.
 @end itemize
 @end table
+
+@item crate
+@cindex crate
+Import metadata from the crates.io Rust package repository
+@uref{https://crates.io, crates.io}.
 @end table
 
 The structure of the @command{guix import} code is modular.  It would be
diff --git a/guix/import/crate.scm b/guix/import/crate.scm
new file mode 100644
index 0000000000..e78e3ad9ca
--- /dev/null
+++ b/guix/import/crate.scm
@@ -0,0 +1,125 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2016 David Craven <david@craven.ch>
+;;;
+;;; 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 crate)
+  #:use-module (guix base32)
+  #:use-module (guix build-system cargo)
+  #:use-module ((guix download) #:prefix download:)
+  #:use-module (guix hash)
+  #:use-module (guix http-client)
+  #:use-module (guix import json)
+  #:use-module (guix import utils)
+  #:use-module ((guix licenses) #:prefix license:)
+  #:use-module (guix monads)
+  #:use-module (guix packages)
+  #:use-module (guix upstream)
+  #:use-module (guix utils)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 pretty-print) ; recursive
+  #:use-module (json)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-2)
+  #:use-module (srfi srfi-26)
+  #:export (crate->guix-package
+            guix-package->crate-name))
+
+(define (crate-fetch crate-name callback)
+  "Fetch the metadata for CRATE-NAME from crates.io and call the callback."
+
+  (define (crates->inputs crates)
+    (sort (map (cut assoc-ref <> "crate_id") crates) string-ci<?))
+
+  (define (string->license string)
+    (map spdx-string->license (string-split string #\/)))
+
+  (define (crate-kind-predicate kind)
+    (lambda (dep) (string=? (assoc-ref dep "kind") kind)))
+
+  (and-let* ((crate-json (json-fetch (string-append crate-url crate-name)))
+             (crate (assoc-ref crate-json "crate"))
+             (name (assoc-ref crate "name"))
+             (version (assoc-ref crate "max_version"))
+             (home-page (assoc-ref crate "homepage"))
+             (synopsis (assoc-ref crate "description"))
+             (description (assoc-ref crate "description"))
+             (license (string->license (assoc-ref crate "license")))
+             (path (string-append "/" version "/dependencies"))
+             (deps-json (json-fetch (string-append crate-url name path)))
+             (deps (assoc-ref deps-json "dependencies"))
+             (input-crates (filter (crate-kind-predicate "normal") deps))
+             (native-input-crates
+              (filter (lambda (dep)
+                        (not ((crate-kind-predicate "normal") dep))) deps))
+             (inputs (crates->inputs input-crates))
+             (native-inputs (crates->inputs native-input-crates)))
+    (callback #:name name #:version version
+              #:inputs inputs #:native-inputs native-inputs
+              #:home-page home-page #:synopsis synopsis
+              #:description description #:license license)))
+
+(define* (make-crate-sexp #:key name version inputs native-inputs
+                          home-page synopsis description license
+                          #:allow-other-keys)
+  "Return the `package' s-expression for a rust package with the given NAME,
+VERSION, INPUTS, NATIVE-INPUTS, HOME-PAGE, SYNOPSIS, DESCRIPTION, and LICENSE."
+  (let* ((port (http-fetch (crate-uri name version)))
+         (guix-name (crate-name->package-name name))
+         (inputs (map crate-name->package-name inputs))
+         (native-inputs (map crate-name->package-name native-inputs))
+         (pkg `(package
+                   (name ,guix-name)
+                   (version ,version)
+                   (source (origin
+                             (method url-fetch)
+                             (uri (crate-uri ,name version))
+                             (file-name (string-append name "-" version ".tar.gz"))
+                             (sha256
+                              (base32
+                               ,(bytevector->nix-base32-string (port-sha256 port))))))
+                   (build-system cargo-build-system)
+                   ,@(maybe-native-inputs native-inputs)
+                   ,@(maybe-inputs inputs)
+                   (home-page ,home-page)
+                   (synopsis ,synopsis)
+                   (description ,(beautify-description description))
+                   (license ,(match license
+                               (() #f)
+                               ((license) license)
+                               (_ `(list ,@license)))))))
+         (close-port port)
+         pkg))
+
+(define (crate->guix-package crate-name)
+  "Fetch the metadata for CRATE-NAME from crates.io, and return the
+`package' s-expression corresponding to that package, or #f on failure."
+  (crate-fetch crate-name make-crate-sexp))
+
+(define (guix-package->crate-name package)
+  "Return the crate name of PACKAGE."
+  (and-let* ((origin (package-source package))
+             (uri (origin-uri origin))
+             (crate-url? uri)
+             (len (string-length crate-url))
+             (path (xsubstring uri len))
+             (parts (string-split path #\/)))
+    (match parts
+      ((name _ ...) name))))
+
+(define (crate-name->package-name name)
+  (string-append "rust-" (string-join (string-split name #\_) "-")))
+
diff --git a/guix/scripts/import.scm b/guix/scripts/import.scm
index e54744feca..c671686043 100644
--- a/guix/scripts/import.scm
+++ b/guix/scripts/import.scm
@@ -73,7 +73,7 @@ rather than \\n."
 ;;; Entry point.
 ;;;
 
-(define importers '("gnu" "nix" "pypi" "cpan" "hackage" "elpa" "gem" "cran"))
+(define importers '("gnu" "nix" "pypi" "cpan" "hackage" "elpa" "gem" "cran" "crate"))
 
 (define (resolve-importer name)
   (let ((module (resolve-interface
diff --git a/guix/scripts/import/crate.scm b/guix/scripts/import/crate.scm
new file mode 100644
index 0000000000..4337a0b623
--- /dev/null
+++ b/guix/scripts/import/crate.scm
@@ -0,0 +1,94 @@
+
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2014 David Thompson <davet@gnu.org>
+;;; Copyright © 2016 David Craven <david@craven.ch>
+;;;
+;;; 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 scripts import crate)
+  #:use-module (guix ui)
+  #:use-module (guix utils)
+  #:use-module (guix scripts)
+  #:use-module (guix import crate)
+  #:use-module (guix scripts import)
+  #:use-module (srfi srfi-1)
+  #:use-module (srfi srfi-11)
+  #:use-module (srfi srfi-37)
+  #:use-module (ice-9 match)
+  #:use-module (ice-9 format)
+  #:export (guix-import-crate))
+
+
+;;;
+;;; Command-line options.
+;;;
+
+(define %default-options
+  '())
+
+(define (show-help)
+  (display (_ "Usage: guix import crate PACKAGE-NAME
+Import and convert the crate.io package for PACKAGE-NAME.\n"))
+  (display (_ "
+  -h, --help             display this help and exit"))
+  (display (_ "
+  -V, --version          display version information and exit"))
+  (newline)
+  (show-bug-report-information))
+
+(define %options
+  ;; Specification of the command-line options.
+  (cons* (option '(#\h "help") #f #f
+                 (lambda args
+                   (show-help)
+                   (exit 0)))
+         (option '(#\V "version") #f #f
+                 (lambda args
+                   (show-version-and-exit "guix import crate")))
+         %standard-import-options))
+
+
+;;;
+;;; Entry point.
+;;;
+
+(define (guix-import-crate . args)
+  (define (parse-options)
+    ;; Return the alist of option values.
+    (args-fold* args %options
+                (lambda (opt name arg result)
+                  (leave (_ "~A: unrecognized option~%") name))
+                (lambda (arg result)
+                  (alist-cons 'argument arg result))
+                %default-options))
+
+  (let* ((opts (parse-options))
+         (args (filter-map (match-lambda
+                            (('argument . value)
+                             value)
+                            (_ #f))
+                           (reverse opts))))
+    (match args
+      ((package-name)
+       (let ((sexp (crate->guix-package package-name)))
+         (unless sexp
+           (leave (_ "failed to download meta-data for package '~a'~%")
+                  package-name))
+         sexp))
+      (()
+       (leave (_ "too few arguments~%")))
+      ((many ...)
+       (leave (_ "too many arguments~%"))))))
diff --git a/guix/scripts/refresh.scm b/guix/scripts/refresh.scm
index f8fb3f80ca..72f51cbff8 100644
--- a/guix/scripts/refresh.scm
+++ b/guix/scripts/refresh.scm
@@ -39,6 +39,7 @@
                           %kernel.org-updater))
   #:use-module (guix import elpa)
   #:use-module (guix import cran)
+  #:use-module (guix import crate)
   #:use-module (guix import hackage)
   #:use-module (guix gnupg)
   #:use-module (gnu packages)
diff --git a/tests/crate.scm b/tests/crate.scm
new file mode 100644
index 0000000000..18d5f72a8c
--- /dev/null
+++ b/tests/crate.scm
@@ -0,0 +1,102 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2014 David Thompson <davet@gnu.org>
+;;; Copyright © 2016 David Craven <david@craven.ch>
+;;;
+;;; 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 (test-crate)
+  #:use-module (guix import crate)
+  #:use-module (guix base32)
+  #:use-module (guix build-system cargo)
+  #:use-module (guix hash)
+  #:use-module (guix tests)
+  #:use-module (ice-9 iconv)
+  #:use-module (ice-9 match)
+  #:use-module (srfi srfi-64))
+
+(define test-crate
+  "{
+  \"crate\": {
+    \"max_version\": \"1.0.0\",
+    \"name\": \"foo\",
+    \"license\": \"MIT/Apache-2.0\",
+    \"description\": \"summary\",
+    \"homepage\": \"http://example.com\",
+  }
+}")
+
+(define test-dependencies
+  "{
+  \"dependencies\": [
+     {
+       \"crate_id\": \"bar\",
+       \"kind\": \"normal\",
+     }
+  ]
+}")
+
+(define test-source-hash
+  "")
+
+(test-begin "crate")
+
+(test-equal "guix-package->crate-name"
+  "rustc-serialize"
+  (guix-package->crate-name
+   (dummy-package
+    "rust-rustc-serialize"
+    (source (dummy-origin
+     (uri (crate-uri "rustc-serialize" "1.0")))))))
+
+(test-assert "crate->guix-package"
+  ;; Replace network resources with sample data.
+  (mock ((guix http-client) http-fetch
+         (lambda (url)
+           (match url
+             ("https://crates.io/api/v1/crates/foo"
+              (open-input-string test-crate))
+             ("https://crates.io/api/v1/crates/foo/1.0.0/download"
+              (set! test-source-hash
+                (bytevector->nix-base32-string
+                 (sha256 (string->bytevector "empty file\n" "utf-8"))))
+              (open-input-string "empty file\n"))
+             ("https://crates.io/api/v1/crates/foo/1.0.0/dependencies"
+              (open-input-string test-dependencies))
+             (_ (error "Unexpected URL: " url)))))
+    (match (crate->guix-package "foo")
+      (('package
+         ('name "rust-foo")
+         ('version "1.0.0")
+         ('source ('origin
+                    ('method 'url-fetch)
+                    ('uri ('crate-uri "foo" 'version))
+                    ('file-name ('string-append 'name "-" 'version ".tar.gz"))
+                    ('sha256
+                     ('base32
+                      (? string? hash)))))
+         ('build-system 'cargo-build-system)
+         ('inputs
+          ('quasiquote
+           (("rust-bar" ('unquote 'rust-bar)))))
+         ('home-page "http://example.com")
+         ('synopsis "summary")
+         ('description "summary")
+         ('license ('list 'license:expat 'license:asl2.0)))
+       (string=? test-source-hash hash))
+      (x
+       (pk 'fail x #f)))))
+
+(test-end "crate")