01/13: download: Add Software Heritage as a content-addressed mirror.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository guix.

commit ee2cfdfe86b0ba7de0312592cbfb96ea175e8863
Author: Ludovic Courtès <address@hidden>
Date:   Tue Nov 13 22:26:07 2018 +0100

    download: Add Software Heritage as a content-addressed mirror.
    
    * guix/download.scm (%content-addressed-mirrors): Add Software
    Heritage.
---
 guix/download.scm | 34 ++++++++++++++++++++++------------
 1 file changed, 22 insertions(+), 12 deletions(-)

diff --git a/guix/download.scm b/guix/download.scm
index 9881178..b74fd31 100644
--- a/guix/download.scm
+++ b/guix/download.scm
@@ -373,18 +373,28 @@
   ;; procedure that takes a file name, an algorithm (symbol) and a hash
   ;; (bytevector), and returns a URL or #f.
   ;; Note: Avoid 'https' to mitigate <http://bugs.gnu.org/22774>.
-  ;; TODO: Add more.
-  '(list (lambda (file algo hash)
-           ;; Files served by 'guix publish' are accessible under a single
-           ;; hash algorithm.
-           (string-append "http://mirror.hydra.gnu.org/file/";
-                          file "/" (symbol->string algo) "/"
-                          (bytevector->nix-base32-string hash)))
-         (lambda (file algo hash)
-           ;; 'tarballs.nixos.org' supports several algorithms.
-           (string-append "http://tarballs.nixos.org/";
-                          (symbol->string algo) "/"
-                          (bytevector->nix-base32-string hash)))))
+  '(begin
+     (use-modules (guix base32) (guix base16))
+
+     (list (lambda (file algo hash)
+             ;; Files served by 'guix publish' are accessible under a single
+             ;; hash algorithm.
+             (string-append "http://mirror.hydra.gnu.org/file/";
+                            file "/" (symbol->string algo) "/"
+                            (bytevector->nix-base32-string hash)))
+           (lambda (file algo hash)
+             ;; 'tarballs.nixos.org' supports several algorithms.
+             (string-append "http://tarballs.nixos.org/";
+                            (symbol->string algo) "/"
+                            (bytevector->nix-base32-string hash)))
+           (lambda (file algo hash)
+             ;; Software Heritage usually archives VCS history rather than
+             ;; tarballs, but tarballs are sometimes available (and can be
+             ;; explicitly stored there.)  For example, see
+             ;; 
<https://archive.softwareheritage.org/api/1/content/sha256:92d0fa1c311cacefa89853bdb53c62f4110cdfda3820346b59cbd098f40f955e/>.
+             (string-append 
"http://archive.softwareheritage.org/api/1/content/";
+                            (symbol->string algo) ":"
+                            (bytevector->base16-string hash) "/raw/")))))
 
 (define %content-addressed-mirror-file
   ;; Content-addressed mirrors stored in a file.