Fix some issues with comments.

aaubry · Sep 16, 2016 · a662fe5 · a662fe5
1 parent 5d99489
commit a662fe5
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Showing 5 changed files with 100 additions and 3 deletions.
diff --git a/YamlDotNet.Test/Core/EmitterTests.cs b/YamlDotNet.Test/Core/EmitterTests.cs
@@ -283,6 +283,23 @@ public void CommentsAreEmittedCorrectly()
                 .And.Contain("# Bottom comment");
         }
 
+        [Fact]
+        public void ACommentAsTheFirstEventAddsANewLine()
+        {
+            var events = new ParsingEvent[]
+            {
+                StandaloneComment("Top comment"),
+                Scalar("first").ImplicitPlain,
+            };
+
+            var yaml = EmittedTextFrom(StreamedDocumentWith(events));
+
+            yaml.Should()
+                .Contain("# Top comment")
+                .And.Contain("first")
+                .And.NotContain("# Top commentfirst");
+        }
+
         [Theory]
         [InlineData("Гранит", 28595)] // Cyrillic (ISO)
         [InlineData("ГÀƊȽ˱ώҔׂۋᵷẁό₩וּﺪﺸﻸﭧ╬♫₹Ὰỗ᷁ݭ٭ӢР͞ʓǈĄë0", 65001)] // UTF-8

diff --git a/YamlDotNet.Test/Core/ParserTests.cs b/YamlDotNet.Test/Core/ParserTests.cs
@@ -320,8 +320,8 @@ public void CommentsAreReturnedWhenRequested()
                     # Bottom comment
                 "), skipComments: false)),
                 StreamStart,
-                StandaloneComment("Top comment"),
                 DocumentStart(Implicit),
+                StandaloneComment("Top comment"),
                 BlockSequenceStart,
                 PlainScalar("first"),
                 InlineComment("Comment on first item"),

diff --git a/YamlDotNet.Test/Serialization/SerializationTests.cs b/YamlDotNet.Test/Serialization/SerializationTests.cs
@@ -1302,5 +1302,46 @@ public void AttributeOverridesAndNamingConventionDoNotConflict()
             var deserializedFoo = deserializer.Deserialize<Foo>(yaml);
             Assert.True(deserializedFoo.IsRequired);
         }
+
+        [Fact]
+        public void YamlConvertiblesAreAbleToEmitAndParseComments()
+        {
+            var serializer = new Serializer();
+            var yaml = serializer.Serialize(new CommentWrapper<string> { Comment = "A comment", Value = "The value" });
+
+            var deserializer = new Deserializer();
+            var parser = new Parser(new Scanner(new StringReader(yaml), skipComments: false));
+            var parsed = deserializer.Deserialize<CommentWrapper<string>>(parser);
+
+            Assert.Equal("A comment", parsed.Comment);
+            Assert.Equal("The value", parsed.Value);
+        }
+
+        public class CommentWrapper<T> : IYamlConvertible
+        {
+            public string Comment { get; set; }
+            public T Value { get; set; }
+
+            public void Read(IParser parser, Type expectedType, ObjectDeserializer nestedObjectDeserializer)
+            {
+                var comment = parser.Allow<Comment>();
+                if (comment != null)
+                {
+                    Comment = comment.Value;
+                }
+
+                Value = (T)nestedObjectDeserializer(typeof(T));
+            }
+
+            public void Write(IEmitter emitter, ObjectSerializer nestedObjectSerializer)
+            {
+                if (!string.IsNullOrEmpty(Comment))
+                {
+                    emitter.Emit(new Comment(Comment, false));
+                }
+
+                nestedObjectSerializer(Value, typeof(T));
+            }
+        }
     }
 }
diff --git a/YamlDotNet/Core/Emitter.cs b/YamlDotNet/Core/Emitter.cs
@@ -648,11 +648,12 @@ private void EmitComment(Comment comment)
             }
             else
             {
-                WriteBreak();
+                WriteIndent();
             }
 
             Write("# ");
             Write(comment.Value);
+            WriteBreak();
 
             isIndentation = true;
         }

diff --git a/YamlDotNet/Core/Parser.cs b/YamlDotNet/Core/Parser.cs
@@ -94,7 +94,7 @@ public ParsingEvent Current
             }
         }
 
-        private readonly Queue<Events.ParsingEvent> pendingEvents = new Queue<Events.ParsingEvent>();
+        private readonly EventQueue pendingEvents = new EventQueue();
 
         /// <summary>
         /// Moves to the next event.
@@ -946,5 +946,43 @@ private ParsingEvent ParseFlowMappingValue(bool isEmpty)
             state = ParserState.FlowMappingKey;
             return ProcessEmptyScalar(GetCurrentToken().Start);
         }
+
+        private class EventQueue
+        {
+            // This class is specialized for our specific use case where there are exactly two priority levels.
+            // If more levels are required, a more generic implementation should be used instead.
+            private readonly Queue<ParsingEvent> highPriorityEvents = new Queue<ParsingEvent>();
+            private readonly Queue<ParsingEvent> normalPriorityEvents = new Queue<ParsingEvent>();
+
+            public void Enqueue(ParsingEvent @event)
+            {
+                switch (@event.Type)
+                {
+                    case Events.EventType.StreamStart:
+                    case Events.EventType.DocumentStart:
+                        highPriorityEvents.Enqueue(@event);
+                        break;
+
+                    default:
+                        normalPriorityEvents.Enqueue(@event);
+                        break;
+                }
+            }
+
+            public ParsingEvent Dequeue()
+            {
+                return highPriorityEvents.Count > 0
+                    ? highPriorityEvents.Dequeue()
+                    : normalPriorityEvents.Dequeue();
+            }
+
+            public int Count
+            {
+                get
+                {
+                    return highPriorityEvents.Count + normalPriorityEvents.Count;
+                }
+            }
+        }
     }
 }