internal/rosa: helpers for common url formats

This cleans up call site of NewPackage.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/rosa.go

@@ -4,6 +4,7 @@ package rosa
 import (
 	"errors"
 	"log"
+	"path"
 	"runtime"
 	"slices"
 	"strconv"
@@ -603,3 +604,54 @@ cd '/usr/src/` + name + `/'
 		})...,
 	)
 }
+
+// newTar wraps [pkg.NewHTTPGetTar] with a simpler function signature.
+func newTar(url, checksum string, compression uint32) pkg.Artifact {
+	return pkg.NewHTTPGetTar(nil, url, mustDecode(checksum), compression)
+}
+
+// newFromCPAN is a helper for downloading release from CPAN.
+func newFromCPAN(author, name, version, checksum string) pkg.Artifact {
+	return newTar(
+		"https://cpan.metacpan.org/authors/id/"+
+			author[:1]+"/"+author[:2]+"/"+author+"/"+
+			name+"-"+version+".tar.gz",
+		checksum,
+		pkg.TarGzip,
+	)
+}
+
+// newFromGitLab is a helper for downloading source from GitLab.
+func newFromGitLab(domain, suffix, ref, checksum string) pkg.Artifact {
+	return newTar(
+		"https://"+domain+"/"+suffix+"/-/archive/"+
+			ref+"/"+path.Base(suffix)+"-"+
+			strings.ReplaceAll(ref, "/", "-")+".tar.bz2",
+		checksum,
+		pkg.TarBzip2,
+	)
+}
+
+// newFromGitHub is a helper for downloading source from Microsoft Github.
+func newFromGitHub(suffix, tag, checksum string) pkg.Artifact {
+	return newTar(
+		"https://github.com/"+suffix+
+			"/archive/refs/tags/"+tag+".tar.gz",
+		checksum,
+		pkg.TarGzip,
+	)
+}
+
+// newFromGitHubRelease is a helper for downloading release tarball from
+// Microsoft Github.
+func newFromGitHubRelease(
+	suffix, tag, name, checksum string,
+	compression uint32,
+) pkg.Artifact {
+	return newTar(
+		"https://github.com/"+suffix+
+			"/releases/download/"+tag+"/"+name,
+		checksum,
+		compression,
+	)
+}