1 files changed, 66 insertions, 0 deletions
diff --git a/nixpkgs/pkgs/build-support/coq/meta-fetch/default.nix b/nixpkgs/pkgs/build-support/coq/meta-fetch/default.nix
new file mode 100644
index 000000000000..580d58395ef4
--- /dev/null
+++ b/nixpkgs/pkgs/build-support/coq/meta-fetch/default.nix
@@ -0,0 +1,66 @@
+{ stdenv, fetchzip }@args:
+let lib = import ../extra-lib.nix {inherit (args.stdenv) lib;}; in
+with builtins; with lib;
+let
+  default-fetcher = {domain ? "github.com", owner ? "", repo, rev, name ? "source", sha256 ? null, ...}@args:
+    let ext = if args?sha256 then "zip" else "tar.gz";
+        fmt = if args?sha256 then "zip" else "tarball";
+        pr  = match "^#(.*)$" rev;
+        url = switch-if [
+          { cond = isNull pr && !isNull (match "^github.*" domain);
+            out = "https://${domain}/${owner}/${repo}/archive/${rev}.${ext}"; }
+          { cond = !isNull pr && !isNull (match "^github.*" domain);
+            out = "https://api.${domain}/repos/${owner}/${repo}/${fmt}/pull/${head pr}/head"; }
+          { cond = isNull pr && !isNull (match "^gitlab.*" domain);
+            out = "https://${domain}/${owner}/${repo}/-/archive/${rev}/${repo}-${rev}.${ext}"; }
+          { cond = !isNull (match "(www.)?mpi-sws.org" domain);
+            out = "https://www.mpi-sws.org/~${owner}/${repo}/download/${repo}-${rev}.${ext}";}
+        ] (throw "meta-fetch: no fetcher found for domain ${domain} on ${rev}");
+        fetch = x: if args?sha256 then fetchzip (x // { inherit sha256; }) else fetchTarball x;
+    in fetch { inherit url ; };
+in
+{
+  fetcher ? default-fetcher,
+  location,
+  release ? {},
+  releaseRev ? (v: v),
+}:
+let isVersion      = x: isString x && match "^/.*" x == null && release?${x};
+    shortVersion   = x: if (isString x && match "^/.*" x == null)
+      then findFirst (v: versions.majorMinor v == x) null
+        (sort versionAtLeast (attrNames release))
+      else null;
+    isShortVersion = x: shortVersion x != null;
+    isPathString   = x: isString x && match "^/.*" x != null && pathExists x; in
+arg:
+switch arg [
+  { case = isNull;       out = { version = "broken"; src = ""; broken = true; }; }
+  { case = isPathString; out = { version = "dev"; src = arg; }; }
+  { case = pred.union isVersion isShortVersion;
+    out = let v = if isVersion arg then arg else shortVersion arg; in
+      if !release.${v}?sha256 then throw "meta-fetch: a sha256 must be provided for each release"
+      else {
+        version = release.${v}.version or v;
+        src = release.${v}.src or fetcher (location // { rev = releaseRev v; } // release.${v});
+      };
+    }
+  { case = isString;
+    out = let
+        splitted  = filter isString (split ":" arg);
+        rev       = last splitted;
+        has-owner = length splitted > 1;
+        version   = "dev"; in {
+      inherit version;
+      src = fetcher (location // { inherit rev; } //
+        (optionalAttrs has-owner { owner = head splitted; }));
+    }; }
+  { case = isAttrs;
+    out = let
+    { version = arg.version or "dev";
+      src = (arg.fetcher or fetcher) (location // (arg.location or {}));
+    }; }
+  { case = isPath;
+    out = {
+      version = "dev" ;
+      src = builtins.path {path = arg; name = location.name or "source";}; }; }
+] (throw "not a valid source description")