feat(cask): make cask template helpers more flexible

Helpers available in cask templates can now accept one or more strings
as input, and first asset filename that matches all given strings is
returned.

pkg/cask/release_info.go

@@ -11,9 +11,11 @@ type ReleaseInfo struct {
 	Assets  map[string]*ReleaseAsset
 }
 
-func (s *ReleaseInfo) Asset(nameMatch string) *ReleaseAsset {
-	if a, ok := s.Assets[nameMatch]; ok {
-		return a
+func (s *ReleaseInfo) Asset(needles ...string) *ReleaseAsset {
+	if len(needles) == 1 {
+		if a, ok := s.Assets[needles[0]]; ok {
+			return a
+		}
 	}
 
 	// Dirty and inefficient way to ensure assets are searched in a predictable
@@ -27,16 +29,20 @@ func (s *ReleaseInfo) Asset(nameMatch string) *ReleaseAsset {
 	})
 
 	for _, a := range assets {
-		if strings.Contains(a.Filename, nameMatch) {
-			return a
+		for _, needle := range needles {
+			if !strings.Contains(a.Filename, needle) {
+				continue
+			}
 		}
+
+		return a
 	}
 
 	return nil
 }
 
-func (s *ReleaseInfo) DownloadURL(nameMatch string) string {
-	a := s.Asset(nameMatch)
+func (s *ReleaseInfo) DownloadURL(needles ...string) string {
+	a := s.Asset(needles...)
 	if a == nil {
 		return ""
 	}
@@ -44,8 +50,8 @@ func (s *ReleaseInfo) DownloadURL(nameMatch string) string {
 	return a.DownloadURL
 }
 
-func (s *ReleaseInfo) SHA256(nameMatch string) string {
-	a := s.Asset(nameMatch)
+func (s *ReleaseInfo) SHA256(needles ...string) string {
+	a := s.Asset(needles...)
 	if a == nil {
 		return ""
 	}