Add "merge --input-file-list NAME ..." as a way to exceed CLI limits

Signed-off-by: Jim Klimov <jimklimov@gmail.com>

Author: jimklimov

README.md

@@ -192,6 +192,7 @@ Usage:
   cyclonedx merge [options]
 
 Options:
+  --input-file-list <input-file-list-file>        A single text file with input BOM filenames (one per line).
   --input-files <input-files>                     Input BOM filenames (separate filenames with a space).
   --output-file <output-file>                     Output BOM filename, will write to stdout if no value provided.
   --input-format <autodetect|json|protobuf|xml>   Specify input file format.
@@ -205,6 +206,11 @@ Options:
 Note: To perform a hierarchical merge all BOMs need the subject of the BOM
 described in the metadata component element.
 
+The `--input-file-list` option can be useful if you have so many filenames to
+merge that your shell interpreter command-line limit is exceeded if you list
+them all as `--input-files`, or if your path names have spaces. If you specify
+both options, the effective file lists will be concatenated before merge.
+
 ### Examples
 
 Merge two XML formatted BOMs:  

src/cyclonedx/Commands/MergeCommand.cs

@@ -22,6 +22,7 @@
 using System.Threading.Tasks;
 using CycloneDX.Models;
 using CycloneDX.Utils;
+using System.IO;
 
 namespace CycloneDX.Cli.Commands
 {
@@ -31,6 +32,8 @@ public static void Configure(RootCommand rootCommand)
         {
             Contract.Requires(rootCommand != null);
             var subCommand = new Command("merge", "Merge two or more BOMs");
+            subCommand.Add(new Option<string>("--input-file-list", "A single text file with input BOM filenames (one per line)."));
+            //TBD//subCommand.Add(new Option<string>("--input-file-list0", "A single text file with input BOM filenames (separated by 0x00 characters)."));
             subCommand.Add(new Option<List<string>>("--input-files", "Input BOM filenames (separate filenames with a space)."));
             subCommand.Add(new Option<string>("--output-file", "Output BOM filename, will write to stdout if no value provided."));
             subCommand.Add(new Option<CycloneDXBomFormat>("--input-format", "Specify input file format."));
@@ -61,7 +64,12 @@ public static async Task<int> Merge(MergeCommandOptions options)
                 return (int)ExitCode.ParameterValidationError;
             }
 
-            var inputBoms = await InputBoms(options.InputFiles, options.InputFormat, outputToConsole).ConfigureAwait(false);
+            List<string> InputFiles = (List<string>)options.InputFiles;
+            if (options.InputFilesList != null)
+            {
+                InputFiles.AddRange(File.ReadAllLines(options.InputFilesList));
+            }
+            var inputBoms = await InputBoms(InputFiles, options.InputFormat, outputToConsole).ConfigureAwait(false);
 
             Component bomSubject = null;
             if (options.Group != null || options.Name != null || options.Version != null)

src/cyclonedx/Commands/MergeCommandOptions.cs

@@ -20,6 +20,8 @@ namespace CycloneDX.Cli.Commands
 {
     public class MergeCommandOptions
     {
+        public string InputFilesList { get; set; }
+        //TBD//public string InputFilesList0 { get; set; }
         public IList<string> InputFiles { get; set; }
         public string OutputFile { get; set; }
         public CycloneDXBomFormat InputFormat { get; set; }
@@ -29,4 +31,4 @@ public class MergeCommandOptions
         public string Name { get; set; }
         public string Version { get; set; }
     }
-}
+}