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

* guix/download.scm (%content-addressed-mirrors): Add Software
Heritage.

1 files changed, 22 insertions, 12 deletions

diff --git a/guix/download.scm b/guix/download.scm
index 988117885c..b74fd31c1f 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.