Merge pull request #202 from AArnott/fix197

Return exit code 3 from SignClient when no files will be signed

Author: clairernovotny

src/SignClient/SignCommand.cs

@@ -25,6 +25,7 @@ static class EXIT_CODES
             public const int SUCCESS = 0;
             public const int INVALID_OPTIONS = 1;
             public const int FAILED = 2;
+            public const int NO_INPUTS_FOUND = 3;
         }
 
         public SignCommand(CommandLineApplication signCommandLineApplication)
@@ -168,6 +169,12 @@ CommandOption maxConcurrency
                     return EXIT_CODES.INVALID_OPTIONS;
                 }
 
+                if (inputFiles.Count == 0)
+                {
+                    signCommandLineApplication.Error.WriteLine("No inputs found to sign.");
+                    return EXIT_CODES.NO_INPUTS_FOUND;
+                }
+
                 Parallel.ForEach(inputFiles,new ParallelOptions { MaxDegreeOfParallelism = maxC } , input =>
                 {
                     FileInfo output;