Update sort_imports (#14)

README.md

@@ -38,6 +38,16 @@ the executable is available in your PATH.
 ```
 protoc --lint_out=. *.proto
 ```
+### Optional Checks
+Optional checks are enabled but passing a comma separated list to the protoc
+"parameter". Example:
+```
+protoc --lint_out=sort_imports:. *.proto
+```
+
+Available optional checks:
+*   `sort_imports` - checks that imports are sorted in descending alphabetical
+order.
 
 ## TODO
 *   Write more tests

main.go

@@ -30,23 +30,21 @@ func main() {
 		}
 	)
 
+	data, err := ioutil.ReadAll(os.Stdin)
+	panicOnError(err)
+	panicOnError(proto.Unmarshal(data, &generatorRequest))
+
 	for _, p := range strings.Split(generatorRequest.GetParameter(), ",") {
-		switch p {
+		switch strings.TrimSpace(p) {
+		case "":
+			continue
 		case SortImports:
 			parameters.SortImports = true
 		default:
 			fmt.Fprintf(os.Stderr, "Unmatched parameter: %s", p)
-			totalErrors++
+			os.Exit(1)
 		}
 	}
-	if totalErrors != 0 {
-		os.Exit(1)
-	}
-
-	data, err := ioutil.ReadAll(os.Stdin)
-	panicOnError(err)
-
-	panicOnError(proto.Unmarshal(data, &generatorRequest))
 
 	for _, file := range generatorRequest.GetProtoFile() {
 		numErrors, err := linter.LintProtoFile(linter.Config{