From 3c865357ad2653af33ef8c0c39a21da9b511297c Mon Sep 17 00:00:00 2001
From: andreashuber-lawo <andreas.huber@lawo.com>
Date: Mon, 4 Apr 2016 15:06:33 +0200
Subject: [PATCH] Closes #19

---
 Lawo.EmberPlusSharp/Ember/EmberWriter.cs      |  7 ++++
 .../Model/EmberReaderExtensions.cs            |  5 ---
 Lawo.EmberPlusSharp/Model/NodeBase.cs         | 40 +++++++++++++------
 Lawo/IO/WriteBuffer.cs                        | 11 ++++-
 LawoTest/IO/BufferTest.cs                     |  9 +++--
 5 files changed, 49 insertions(+), 23 deletions(-)

diff --git a/Lawo.EmberPlusSharp/Ember/EmberWriter.cs b/Lawo.EmberPlusSharp/Ember/EmberWriter.cs
index 107664ce..3ea2f4f2 100644
--- a/Lawo.EmberPlusSharp/Ember/EmberWriter.cs
+++ b/Lawo.EmberPlusSharp/Ember/EmberWriter.cs
@@ -264,6 +264,13 @@ public void WriteEndContainer()
             WriteLength(this.writeBuffer, 0, 0, 1);
         }
 
+        /// <summary>Flushes the internal buffer into the stream passed to the constructor.</summary>
+        public void Flush()
+        {
+            this.AssertNotDisposed();
+            this.writeBuffer.Flush();
+        }
+
         ////////////////////////////////////////////////////////////////////////////////////////////////////////////////
 
         private void AssertNotDisposed()
diff --git a/Lawo.EmberPlusSharp/Model/EmberReaderExtensions.cs b/Lawo.EmberPlusSharp/Model/EmberReaderExtensions.cs
index 069a2c3d..3a466454 100644
--- a/Lawo.EmberPlusSharp/Model/EmberReaderExtensions.cs
+++ b/Lawo.EmberPlusSharp/Model/EmberReaderExtensions.cs
@@ -13,11 +13,6 @@ namespace Lawo.EmberPlusSharp.Model
 
     internal static class EmberReaderExtensions
     {
-        internal static void AssertRead(this EmberReader reader)
-        {
-            AssertRead(reader, null);
-        }
-
         internal static bool AssertAndReadContentsAsBoolean(this EmberReader reader)
         {
             return AssertAndReadContents(reader, r => r.ReadContentsAsBoolean());
diff --git a/Lawo.EmberPlusSharp/Model/NodeBase.cs b/Lawo.EmberPlusSharp/Model/NodeBase.cs
index 4b03ab3e..02e3d4a9 100644
--- a/Lawo.EmberPlusSharp/Model/NodeBase.cs
+++ b/Lawo.EmberPlusSharp/Model/NodeBase.cs
@@ -8,6 +8,7 @@ namespace Lawo.EmberPlusSharp.Model
 {
     using System.Collections.Generic;
     using System.ComponentModel;
+    using System.IO;
     using System.Linq;
     using System.Text;
 
@@ -319,24 +320,37 @@ private void ReadChildContents(
             }
             else
             {
-                reader.AssertRead();
-
-                if (reader.CanReadContents && (reader.OuterId == GlowNodeContents.Identifier.OuterId))
+                using (var stream = new MemoryStream())
+                using (var writer = new EmberWriter(stream))
                 {
-                    var context = new Context(this, number, reader.AssertAndReadContentsAsString());
-                    child = this.ReadNewChildContents(reader, actualType, context, out childRequestState);
+                    // Since EmberReader checks that every end of a container is matched by a start, we need to write
+                    // this dummy here.
+                    writer.WriteStartSet(GlowNode.Contents.OuterId);
+                    var identifier = reader.CopyToEndContainer(writer, GlowNodeContents.Identifier.OuterId) as string;
+
+                    if (identifier != null)
+                    {
+                        writer.Flush();
+                        stream.Position = 0;
 
-                    if (child != null)
+                        using (var contentsReader = new EmberReader(stream))
+                        {
+                            contentsReader.Read(); // Read what we have written with WriteStartSet above
+                            var context = new Context(this, number, identifier);
+                            child = this.ReadNewChildContents(contentsReader, actualType, context, out childRequestState);
+
+                            if (child != null)
+                            {
+                                this.children.Add(number, child);
+                            }
+                        }
+                    }
+                    else
                     {
-                        this.children.Add(number, child);
+                        childRequestState = RequestState.Complete;
+                        child = null;
                     }
                 }
-                else
-                {
-                    reader.SkipToEndContainer();
-                    childRequestState = RequestState.Complete;
-                    child = null;
-                }
             }
         }
 
diff --git a/Lawo/IO/WriteBuffer.cs b/Lawo/IO/WriteBuffer.cs
index 0c0800ab..d7eea6ae 100644
--- a/Lawo/IO/WriteBuffer.cs
+++ b/Lawo/IO/WriteBuffer.cs
@@ -113,8 +113,15 @@ public WriteBuffer(WriteAsyncCallback writeAsync, int bufferSize) : base(bufferS
         public bool Flush()
         {
             var count = this.Count;
-            this.Count = 0; // Make sure that the buffer is empty even if write throws
-            this.write(this.GetBuffer(), 0, count);
+
+            // Prevent call to this.write when buffer is empty so that there is no error when the underlying stream has
+            // already been disposed.
+            if (count > 0)
+            {
+                this.Count = 0; // Make sure that the buffer is empty even if write throws
+                this.write(this.GetBuffer(), 0, count);
+            }
+
             return true;
         }
 
diff --git a/LawoTest/IO/BufferTest.cs b/LawoTest/IO/BufferTest.cs
index 60d9378a..c9096769 100644
--- a/LawoTest/IO/BufferTest.cs
+++ b/LawoTest/IO/BufferTest.cs
@@ -184,11 +184,14 @@ await AssertThrowAsync<InvalidOperationException>(
                             () => writeBuffer.WriteAsync(new byte[3], 0, 3, CancellationToken.None));
 
                         var asyncWriteBuffer = new WriteBuffer((WriteAsyncCallback)stream.WriteAsync, 1);
+                        asyncWriteBuffer[asyncWriteBuffer.Count++] = 42;
+                        AssertThrow<InvalidOperationException>(() => asyncWriteBuffer.Flush());
+                        asyncWriteBuffer[asyncWriteBuffer.Count++] = 42;
+                        AssertThrow<InvalidOperationException>(
+                            () => asyncWriteBuffer.Reserve(2), () => asyncWriteBuffer.Write(new byte[3], 0, 3));
+                        asyncWriteBuffer[asyncWriteBuffer.Count++] = 42;
                         var str = "Hello";
                         AssertThrow<InvalidOperationException>(
-                            () => asyncWriteBuffer.Flush(),
-                            () => asyncWriteBuffer.Reserve(2),
-                            () => asyncWriteBuffer.Write(new byte[3], 0, 3),
                             () => asyncWriteBuffer.WriteAsUtf8(str, Encoding.UTF8.GetByteCount(str)));
                     }
                 });