[PATCH] Add support for 'cvs-fetch' method in origins

[Mark H Weaver]

The motivation for this is libffcall, which hasn't been released in such
a long time that http://gnu.org/s/libffcall doesn't even link to the
last release, but just says to download it from CVS.

guix/cvs-download.scm is based so heavily on guix/svn-download.scm that
I copied the copyright notices from svn-download.scm.

      Mark

>From 118c8b739f368e4e5f691e119618568dcda0e12b Mon Sep 17 00:00:00 2001
From: Mark H Weaver <address@hidden>
Date: Sat, 17 Jan 2015 22:11:45 -0500
Subject: [PATCH] Add support for 'cvs-fetch' method in origins.

* guix/cvs-download.scm, guix/build/cvs.scm: New files.
* Makefile.am (MODULES): Add them.
---
 Makefile.am           |  2 ++
 guix/build/cvs.scm    | 65 +++++++++++++++++++++++++++++++++++++++
 guix/cvs-download.scm | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 151 insertions(+)
 create mode 100644 guix/build/cvs.scm
 create mode 100644 guix/cvs-download.scm

diff --git a/Makefile.am b/Makefile.am
index 67367d6..2e0da77 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -60,6 +60,7 @@ MODULES =                                     \
   guix/gnupg.scm                               \
   guix/elf.scm                                 \
   guix/store.scm                               \
+  guix/cvs-download.scm                                \
   guix/svn-download.scm                                \
   guix/ui.scm                                  \
   guix/build/download.scm                      \
@@ -76,6 +77,7 @@ MODULES =                                     \
   guix/build/union.scm                         \
   guix/build/pull.scm                          \
   guix/build/rpath.scm                         \
+  guix/build/cvs.scm                           \
   guix/build/svn.scm                           \
   guix/build/syscalls.scm                      \
   guix/build/emacs-utils.scm                   \
diff --git a/guix/build/cvs.scm b/guix/build/cvs.scm
new file mode 100644
index 0000000..18b138c
--- /dev/null
+++ b/guix/build/cvs.scm
@@ -0,0 +1,65 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2015 Mark H Weaver <address@hidden>
+;;;
+;;; 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 build cvs)
+  #:use-module (guix build utils)
+  #:use-module (ice-9 regex)
+  #:use-module (ice-9 ftw)
+  #:export (cvs-fetch))
+
+;;; Commentary:
+;;;
+;;; This is the build-side support code of (guix cvs-download).  It allows a
+;;; CVS repository to be checked out at a specific revision or date.
+;;;
+;;; Code:
+
+(define (find-cvs-directories)
+  (define (enter? path st result)
+    (not (string-suffix? "/CVS" path)))
+  (define (leaf path st result) result)
+  (define (down path st result) result)
+  (define (up   path st result) result)
+  (define (skip path st result)
+    (if (and (string-suffix? "/CVS" path)
+             (eqv? 'directory (stat:type st)))
+        (cons path result)
+        result))
+  (define (error path st errno result)
+    (format (current-error-port) "cvs-fetch: ~a: ~a~%"
+            path (strerror errno)))
+  (file-system-fold enter? leaf down up skip error '() "." lstat))
+
+(define* (cvs-fetch cvs-root-dir module revision directory
+                    #:key (cvs-command "cvs"))
+  "Fetch REVISION from MODULE of CVS-ROOT-DIR into DIRECTORY.  REVISION must
+either be a date in ISO-8601 format (e.g. \"2012-12-21\") or a CVS tag.
+Return #t on success, #f otherwise."
+  (and (zero? (system* cvs-command "-z3"
+                       "-d" cvs-root-dir
+                       "checkout"
+                       (if (string-match "^[0-9]{4}-[0-9]{2}-[0-9]{2}$" 
revision)
+                           "-D" "-r")
+                       revision
+                       module))
+       (rename-file module directory)
+       (with-directory-excursion directory
+         (for-each delete-file-recursively (find-cvs-directories)))
+       #t))
+
+;;; cvs.scm ends here
diff --git a/guix/cvs-download.scm b/guix/cvs-download.scm
new file mode 100644
index 0000000..e3d8ad1
--- /dev/null
+++ b/guix/cvs-download.scm
@@ -0,0 +1,84 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2014, 2015 Ludovic Courtès <address@hidden>
+;;; Copyright © 2014 Sree Harsha Totakura <address@hidden>
+;;; Copyright © 2015 Mark H Weaver <address@hidden>
+;;;
+;;; 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 cvs-download)
+  #:use-module (guix records)
+  #:use-module (guix gexp)
+  #:use-module (guix store)
+  #:use-module (guix monads)
+  #:use-module (guix packages)
+  #:use-module (ice-9 match)
+  #:export (cvs-reference
+            cvs-reference?
+            cvs-reference-url
+            cvs-reference-revision
+            cvs-fetch))
+
+;;; Commentary:
+;;;
+;;; An <origin> method that fetches a specific revision or date from a CVS
+;;; repository.  The CVS-ROOT-DIR, MODULE and REVISION are specified with a
+;;; <cvs-reference> object.  REVISION should be specified as either a date
+;;; string in ISO-8601 format (e.g. "2012-12-21") or a CVS tag.
+;;;
+;;; Code:
+
+(define-record-type* <cvs-reference>
+  cvs-reference make-cvs-reference
+  cvs-reference?
+  (root-dir cvs-reference-root-dir)               ; string
+  (module   cvs-reference-module)                 ; string
+  (revision cvs-reference-revision))              ; string
+
+(define (cvs-package)
+  "Return the default CVS package."
+  (let ((distro (resolve-interface '(gnu packages version-control))))
+    (module-ref distro 'cvs)))
+
+(define* (cvs-fetch ref hash-algo hash
+                    #:optional name
+                    #:key (system (%current-system)) (guile (default-guile))
+                    (cvs (cvs-package)))
+  "Return a fixed-output derivation that fetches REF, a <cvs-reference>
+object.  The output is expected to have recursive hash HASH of type
+HASH-ALGO (a symbol).  Use NAME as the file name, or a generic name if #f."
+  (define build
+    #~(begin
+        (use-modules (guix build cvs))
+        (cvs-fetch '#$(cvs-reference-root-dir ref)
+                   '#$(cvs-reference-module ref)
+                   '#$(cvs-reference-revision ref)
+                   #$output
+                   #:cvs-command (string-append #$cvs "/bin/cvs"))))
+
+  (mlet %store-monad ((guile (package->derivation guile system)))
+    (gexp->derivation (or name "cvs-checkout") build
+                      #:system system
+                      ;; FIXME: See <https://bugs.gnu.org/18747>.
+                      ;;#:local-build? #t
+                      #:hash-algo hash-algo
+                      #:hash hash
+                      #:recursive? #t
+                      #:modules '((guix build cvs)
+                                  (guix build utils))
+                      #:guile-for-build guile
+                      #:local-build? #t)))
+
+;;; cvs-download.scm ends here
-- 
2.2.1