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.

1 files changed, 125 insertions, 0 deletions

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 #\_) "-")))
+