Streamline AndroidMk generation

Add AndroidMkEmitAssignList to emit a line to assign the items from
the given list of string arrays.

Test: treehugger
Change-Id: Id5acbef38ea4e91349bd2461f226db352d4b8123

android/androidmk.go

@@ -489,11 +489,11 @@ func (a *AndroidMkEntries) GetDistForGoals(mod blueprint.Module) []string {
 // Write the license variables to Make for AndroidMkData.Custom(..) methods that do not call WriteAndroidMkData(..)
 // It's required to propagate the license metadata even for module types that have non-standard interfaces to Make.
 func (a *AndroidMkEntries) WriteLicenseVariables(w io.Writer) {
-	fmt.Fprintln(w, "LOCAL_LICENSE_KINDS :=", strings.Join(a.EntryMap["LOCAL_LICENSE_KINDS"], " "))
-	fmt.Fprintln(w, "LOCAL_LICENSE_CONDITIONS :=", strings.Join(a.EntryMap["LOCAL_LICENSE_CONDITIONS"], " "))
-	fmt.Fprintln(w, "LOCAL_NOTICE_FILE :=", strings.Join(a.EntryMap["LOCAL_NOTICE_FILE"], " "))
+	AndroidMkEmitAssignList(w, "LOCAL_LICENSE_KINDS", a.EntryMap["LOCAL_LICENSE_KINDS"])
+	AndroidMkEmitAssignList(w, "LOCAL_LICENSE_CONDITIONS", a.EntryMap["LOCAL_LICENSE_CONDITIONS"])
+	AndroidMkEmitAssignList(w, "LOCAL_NOTICE_FILE", a.EntryMap["LOCAL_NOTICE_FILE"])
 	if pn, ok := a.EntryMap["LOCAL_LICENSE_PACKAGE_NAME"]; ok {
-		fmt.Fprintln(w, "LOCAL_LICENSE_PACKAGE_NAME :=", strings.Join(pn, " "))
+		AndroidMkEmitAssignList(w, "LOCAL_LICENSE_PACKAGE_NAME", pn)
 	}
 }
 
@@ -672,7 +672,7 @@ func (a *AndroidMkEntries) write(w io.Writer) {
 
 	w.Write(a.header.Bytes())
 	for _, name := range a.entryOrder {
-		fmt.Fprintln(w, name+" := "+strings.Join(a.EntryMap[name], " "))
+		AndroidMkEmitAssignList(w, name, a.EntryMap[name])
 	}
 	w.Write(a.footer.Bytes())
 }
@@ -972,3 +972,28 @@ func AndroidMkDataPaths(data []DataPath) []string {
 	}
 	return testFiles
 }
+
+// AndroidMkEmitAssignList emits the line
+//
+//	VAR := ITEM ...
+//
+// Items are the elements to the given set of lists
+// If all the passed lists are empty, no line will be emitted
+func AndroidMkEmitAssignList(w io.Writer, varName string, lists ...[]string) {
+	doPrint := false
+	for _, l := range lists {
+		if doPrint = len(l) > 0; doPrint {
+			break
+		}
+	}
+	if !doPrint {
+		return
+	}
+	fmt.Fprint(w, varName, " :=")
+	for _, l := range lists {
+		for _, item := range l {
+			fmt.Fprint(w, " ", item)
+		}
+	}
+	fmt.Fprintln(w)
+}