Merge pull request #62 from jonsequitur/LegalFilePathsOnly-rule

add LegalFilePathsOnly arguments rule

CommandLine.Tests/ParsingValidationTests.cs

@@ -99,6 +99,39 @@ namespace Microsoft.DotNet.Cli.CommandLine.Tests
                 .Contain("Options '--one' and '--two' cannot be used together.");
         }
 
+        [Fact]
+        public void LegalFilePathsOnly_rejects_arguments_containing_invalid_path_characters()
+        {
+            var command = Command("the-command", "",
+                                  ZeroOrMoreArguments()
+                                      .LegalFilePathsOnly());
+
+            var invalidCharacters = $"|{Path.GetInvalidPathChars().First()}|";
+
+            output.WriteLine(string.Join("\n", Path.GetInvalidPathChars()));
+
+            var result = command.Parse($"the-command {invalidCharacters}");
+
+            result.UnmatchedTokens
+                  .Should()
+                  .BeEquivalentTo(invalidCharacters);
+        }
+
+        [Fact]
+        public void LegalFilePathsOnly_accepts_arguments_containing_valid_path_characters()
+        {
+            var command = Command("the-command", "",
+                                  ZeroOrMoreArguments()
+                                      .LegalFilePathsOnly());
+
+            var validPathName = Directory.GetCurrentDirectory();
+            var validNonExistingFileName = Path.Combine(validPathName, Guid.NewGuid().ToString());
+
+            var result = command.Parse($"the-command {validPathName} {validNonExistingFileName}");
+
+            result.Errors.Should().BeEmpty();
+        }
+
         [Fact]
         public void An_argument_can_be_invalid_based_on_file_existence()
         {

CommandLine/Accept.cs

@@ -86,6 +86,29 @@ namespace Microsoft.DotNet.Cli.CommandLine
                 return null;
             }));
 
+        public static ArgumentsRule LegalFilePathsOnly(
+            this ArgumentsRule rule) =>
+            rule.And(new ArgumentsRule(o =>
+            {
+                foreach (var arg in o.Arguments)
+                {
+                    try
+                    {
+                        var fileInfo = new FileInfo(arg);
+                    }
+                    catch (NotSupportedException ex)
+                    {
+                        return ex.Message;
+                    }
+                    catch (ArgumentException ex)
+                    {
+                        return ex.Message;
+                    }
+                }
+
+                return null;
+            }));
+
         public static ArgumentsRule WithSuggestionsFrom(
             params string[] values) =>
             new ArgumentsRule(