msgpart: factorize mime type and filename construction

Reduce code duplication.

Signed-off-by: Robin Jarry <robin@jarry.cc>
Acked-by: Moritz Poldrack <moritz@poldrack.dev>

commands/msg/forward.go

@@ -198,7 +198,7 @@ func (forward) Execute(aerc *widgets.Aerc, args []string) error {
 						continue
 					}
 					store.FetchBodyPart(msg.Uid, p, func(reader io.Reader) {
-						mime := fmt.Sprintf("%s/%s", bs.MIMEType, bs.MIMESubType)
+						mime := bs.FullMIMEType()
 						params := lib.SetUtf8Charset(bs.Params)
 						name, ok := params["name"]
 						if !ok {

commands/msg/recall.go

@@ -204,7 +204,7 @@ func (Recall) Execute(aerc *widgets.Aerc, args []string) error {
 						continue
 					}
 					msg.FetchBodyPart(p, func(reader io.Reader) {
-						mime := fmt.Sprintf("%s/%s", bs.MIMEType, bs.MIMESubType)
+						mime := bs.FullMIMEType()
 						params := lib.SetUtf8Charset(bs.Params)
 						name, ok := params["name"]
 						if !ok {

commands/msg/reply.go

@@ -326,7 +326,7 @@ func addMimeType(msg *models.MessageInfo, part []int,
 	if err != nil {
 		return err
 	}
-	orig.MIMEType = fmt.Sprintf("%s/%s", bs.MIMEType, bs.MIMESubType)
+	orig.MIMEType = bs.FullMIMEType()
 	return nil
 }
 

commands/msgview/open.go

@@ -1,7 +1,6 @@
 package msgview
 
 import (
-	"fmt"
 	"io"
 	"mime"
 	"os"
@@ -52,7 +51,7 @@ func (Open) Execute(aerc *widgets.Aerc, args []string) error {
 
 		// try to determine the correct extension based on mimetype
 		if part, err := mv.MessageView().BodyStructure().PartAtIndex(p.Index); err == nil {
-			mimeType = fmt.Sprintf("%s/%s", part.MIMEType, part.MIMESubType)
+			mimeType = part.FullMIMEType()
 			if exts, _ := mime.ExtensionsByType(mimeType); len(exts) > 0 {
 				extension = exts[0]
 			}

commands/msgview/save.go

@@ -215,12 +215,7 @@ func isAbsPath(path string) bool {
 // generateFilename tries to get the filename from the given part.
 // if that fails it will fallback to a generated one based on the date
 func generateFilename(part *models.BodyStructure) string {
-	var filename string
-	if fn, ok := part.DispositionParams["filename"]; ok {
-		filename = fn
-	} else if fn, ok := part.Params["name"]; ok {
-		filename = fn
-	}
+	filename := part.FileName()
 	// Some MUAs send attachments with names like /some/stupid/idea/happy.jpeg
 	// Assuming non hostile intent it does make sense to use just the last
 	// portion of the pathname as the filename for saving it.