Make mk2rbc accept either a makefile or product

The current behavior of mk2rbc is that it can accept either
a makefile to convert, or if it's also generating a launcher,
it must accept a product name instead of a makefile.

For board configuration, we need to convert a specific makefile,
but we also want to generate a launcher. Change mk2rbc so that
its non-flag arguments can be either makefiles or product names.

Bug: 201700692
Test: ./build/bazel/ci/rbc_product_config.sh aosp_arm64-userdebug
      with board config changes patched in
Change-Id: I521e31fe0bdc608b8f26c9aa803ca690dd1c538e

mk2rbc/cmd/mk2rbc.go

@@ -154,47 +154,49 @@ func main() {
 	}
 
 	// Convert!
-	ok := true
-	if *launcher != "" {
-		if len(flag.Args()) != 1 {
-			quit(fmt.Errorf("a launcher can be generated only for a single product"))
-		}
-		product := flag.Args()[0]
+	files := flag.Args()
 	productConfigMap := buildProductConfigMap()
-		path, found := productConfigMap[product]
-		if !found {
-			quit(fmt.Errorf("cannot generate configuration launcher for %s, it is not a known product",
-				product))
+	if *allInSource {
+		for _, path := range productConfigMap {
+			files = append(files, path)
+		}
+	}
+	for i, file := range files {
+		if _, err := os.Stat(file); os.IsNotExist(err) {
+			temp, ok := productConfigMap[file]
+			if ok {
+				files[i] = temp
+			} else {
+				quit(fmt.Errorf("%s is neither a product makefile nor a product name", file))
+			}
+		}
+	}
+	ok := true
+	for _, mkFile := range files {
+		ok = convertOne(mkFile) && ok
+	}
+
+	if *launcher != "" {
+		if len(files) != 1 {
+			quit(fmt.Errorf("a launcher can be generated only for a single product"))
 		}
 		versionDefaults, err := generateVersionDefaults()
 		if err != nil {
 			quit(err)
 		}
-		ok = convertOne(path) && ok
 		versionDefaultsPath := outputFilePath(versionDefaultsMk)
 		err = writeGenerated(versionDefaultsPath, versionDefaults)
 		if err != nil {
-			fmt.Fprintf(os.Stderr, "%s:%s", path, err)
+			fmt.Fprintf(os.Stderr, "%s:%s", files[0], err)
 			ok = false
 		}
 
-		err = writeGenerated(*launcher, mk2rbc.Launcher(outputFilePath(path), versionDefaultsPath,
-			mk2rbc.MakePath2ModuleName(path)))
+		err = writeGenerated(*launcher, mk2rbc.Launcher(outputFilePath(files[0]), versionDefaultsPath,
+			mk2rbc.MakePath2ModuleName(files[0])))
 		if err != nil {
-			fmt.Fprintf(os.Stderr, "%s:%s", path, err)
+			fmt.Fprintf(os.Stderr, "%s:%s", files[0], err)
 			ok = false
 		}
-	} else {
-		files := flag.Args()
-		if *allInSource {
-			productConfigMap := buildProductConfigMap()
-			for _, path := range productConfigMap {
-				files = append(files, path)
-			}
-		}
-		for _, mkFile := range files {
-			ok = convertOne(mkFile) && ok
-		}
 	}
 
 	printStats()