From 8d8c0584730647e9be0ab9a662a875362a8c45c0 Mon Sep 17 00:00:00 2001
From: SzymonPobiega <szymon.pobiega@gmail.com>
Date: Thu, 17 Aug 2017 10:59:30 +0200
Subject: [PATCH] Allow statement-bodied properties in sagas

---
 ...est.WithStatementBodyProperty.approved.txt |  6 +++
 .../Saga/SagaDefinitionReaderTest.cs          | 30 ++++++++++++++
 src/ScriptBuilder/CecilExtensions.cs          | 41 ++++++++++++++++++-
 3 files changed, 75 insertions(+), 2 deletions(-)
 create mode 100644 src/ScriptBuilder.Tests/Saga/SagaDefinitionReaderTest.WithStatementBodyProperty.approved.txt

diff --git a/src/ScriptBuilder.Tests/Saga/SagaDefinitionReaderTest.WithStatementBodyProperty.approved.txt b/src/ScriptBuilder.Tests/Saga/SagaDefinitionReaderTest.WithStatementBodyProperty.approved.txt
new file mode 100644
index 000000000..bad9f5579
--- /dev/null
+++ b/src/ScriptBuilder.Tests/Saga/SagaDefinitionReaderTest.WithStatementBodyProperty.approved.txt
@@ -0,0 +1,6 @@
+{
+  "TableSuffix": "WithStatementBodyPropertySaga",
+  "CorrelationProperty": null,
+  "TransitionalCorrelationProperty": null,
+  "Name": "SagaDefinitionReaderTest/WithStatementBodyPropertySaga"
+}
\ No newline at end of file
diff --git a/src/ScriptBuilder.Tests/Saga/SagaDefinitionReaderTest.cs b/src/ScriptBuilder.Tests/Saga/SagaDefinitionReaderTest.cs
index 389f28ac3..efd97c313 100644
--- a/src/ScriptBuilder.Tests/Saga/SagaDefinitionReaderTest.cs
+++ b/src/ScriptBuilder.Tests/Saga/SagaDefinitionReaderTest.cs
@@ -209,4 +209,34 @@ protected override void ConfigureMapping(IMessagePropertyMapper mapper)
         {
         }
     }
+
+    [Test]
+    public void WithStatementBodyProperty()
+    {
+        var sagaType = module.GetTypeDefinition<WithStatementBodyPropertySaga>();
+        SagaDefinitionReader.TryGetSqlSagaDefinition(sagaType, out var definition);
+        ObjectApprover.VerifyWithJson(definition);
+    }
+
+    public class WithStatementBodyPropertySaga : SqlSaga<WithStatementBodyPropertySaga.SagaData>
+    {
+        public class SagaData : ContainSagaData
+        {
+        }
+
+        protected override string CorrelationPropertyName
+        {
+            //Explicitly not use expression body
+            get { return null; }
+        }
+
+        protected override void ConfigureMapping(IMessagePropertyMapper mapper)
+        {
+        }
+    }
+
+    public void Dispose()
+    {
+        module?.Dispose();
+    }
 }
\ No newline at end of file
diff --git a/src/ScriptBuilder/CecilExtensions.cs b/src/ScriptBuilder/CecilExtensions.cs
index 73e759af5..288ec4504 100644
--- a/src/ScriptBuilder/CecilExtensions.cs
+++ b/src/ScriptBuilder/CecilExtensions.cs
@@ -2,6 +2,7 @@
 using System.Linq;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
+using Mono.Collections.Generic;
 using NServiceBus.Persistence.Sql;
 
 static class CecilExtensions
@@ -42,10 +43,22 @@ public static bool TryGetPropertyAssignment(this PropertyDefinition property, ou
     {
         value = null;
         var instructions = property.GetMethod.Body.Instructions;
-        if (instructions.Count != 2)
+        if (instructions.Count == 2)
         {
-            return false;
+            //Ldstr-Ret
+            return TryGetExpressionBodyPropertyAssignment(instructions, out value);
+        }
+        if (instructions.Count == 6)
+        {
+            //Nop-Ldstr-Stloc.0-Br.S-Ldloc.0-Ret
+            return TryGetStatementBodyPropertyAssignment(instructions, out value);
         }
+        return false;
+    }
+
+    static bool TryGetExpressionBodyPropertyAssignment(Collection<Instruction> instructions, out string value)
+    {
+        value = null;
         if (instructions[1].OpCode != OpCodes.Ret)
         {
             return false;
@@ -63,6 +76,30 @@ public static bool TryGetPropertyAssignment(this PropertyDefinition property, ou
         return false;
     }
 
+    static bool TryGetStatementBodyPropertyAssignment(Collection<Instruction> instructions, out string value)
+    {
+        value = null;
+        if (instructions[5].OpCode != OpCodes.Ret
+            || instructions[4].OpCode != OpCodes.Ldloc_0
+            || instructions[3].OpCode != OpCodes.Br_S
+            || instructions[2].OpCode != OpCodes.Stloc_0
+            || instructions[0].OpCode != OpCodes.Nop)
+        {
+            return false;
+        }
+        var first = instructions[1];
+        if (first.OpCode == OpCodes.Ldstr)
+        {
+            value = (string)first.Operand;
+            return true;
+        }
+        if (first.OpCode == OpCodes.Ldnull)
+        {
+            return true;
+        }
+        return false;
+    }
+
     public static CustomAttribute GetSingleAttribute(this TypeDefinition type, string attributeName)
     {
         return type.CustomAttributes.SingleOrDefault(x => x.AttributeType.FullName == attributeName);