From 1166d2811a7f6480a86aaeae3872723043760ef7 Mon Sep 17 00:00:00 2001
From: Mike Bierlee <m.bierlee@lostmoment.com>
Date: Sat, 13 Dec 2014 22:06:11 +0100
Subject: [PATCH] Add @Qualifier UDA for qualifying members typed by supertype

---
 README.md                    |  8 ++++++
 source/poodinis/autowire.d   | 51 ++++++++++++++++++++++++++-------
 test/poodinis/autowiretest.d | 55 ++++++++++++++++++++++++++++++++----
 3 files changed, 98 insertions(+), 16 deletions(-)

diff --git a/README.md b/README.md
index 8c58e46..648e400 100644
--- a/README.md
+++ b/README.md
@@ -130,6 +130,14 @@ container.register!(Color, Blue);
 container.register!(Color, Red);
 auto blueInstance = container.resolve!(Color, Blue);
 ```
+If you want to autowire a type registered to multiple concrete types, use the @Qualifier UDA:
+```d
+class BluePaint {
+	@Autowire
+	@Qualifier!Blue
+	public Color color;
+}
+```
 If you registered multiple concrete types to the same supertype and you do not resolve using a qualifier, a ResolveException is throw stating that there are multiple candidates for the type to be resolved.
 
 Known issues
diff --git a/source/poodinis/autowire.d b/source/poodinis/autowire.d
index f31541a..a5ace16 100644
--- a/source/poodinis/autowire.d
+++ b/source/poodinis/autowire.d
@@ -18,30 +18,61 @@ debug {
 
 class Autowire{};
 
+struct Qualifier(T) {
+	T qualifier;
+}
+
 alias Autowired = Autowire;
 
 public void autowire(Type)(DependencyContainer container, Type instance) {
+	// For the love of god, refactor this!
+	
 	debug {
-		auto memberType = typeid(Type);
+		auto instanceType = typeid(Type);
 		auto instanceAddress = &instance;
-		writeln(format("DEBUG: Autowiring members of [%s@%s]", memberType, instanceAddress));
+		writeln(format("DEBUG: Autowiring members of [%s@%s]", instanceType, instanceAddress));
 	}
 	
 	foreach (member ; __traits(allMembers, Type)) {
-		static if(__traits(compiles, __traits( getMember, Type, member )) && __traits(compiles, __traits(getAttributes, __traits(getMember, Type, member )))) {
-			foreach(attribute; __traits(getAttributes, __traits(getMember, Type, member))) {
-				static if (is(attribute : Autowire)) {
+		static if(__traits(compiles, __traits(getMember, Type, member)) && __traits(compiles, __traits(getAttributes, __traits(getMember, Type, member)))) {
+			foreach(autowireAttribute; __traits(getAttributes, __traits(getMember, Type, member))) {
+				static if (is(autowireAttribute : Autowire)) {
 					if (__traits(getMember, instance, member) is null) {
 						alias TypeTuple!(__traits(getMember, instance, member)) memberReference;
-						auto autowirableInstance = container.resolve!(typeof(memberReference));
+						alias MemberType = typeof(memberReference)[0];
 						debug {
-							auto autowirableType = typeid(typeof(memberReference[0]));
-							auto autowireableAddress = &autowirableInstance;
-							writeln(format("DEBUG: Autowire instance [%s@%s] to [%s@%s].%s", autowirableType, autowireableAddress, memberType, instanceAddress, member));
+							string qualifiedInstanceTypeString = typeid(MemberType).toString;
 						}
 						
-						__traits(getMember, instance, member) = autowirableInstance;
+						MemberType qualifiedInstance;
+						auto resolvedThroughQualifier = false;
+						foreach (qualifierAttribute; __traits(getAttributes, __traits(getMember, Type, member))) {
+							static if (is(qualifierAttribute == Qualifier!T, T)) {
+								alias QualifierType = typeof(qualifierAttribute.qualifier);
+								qualifiedInstance = container.resolve!(typeof(memberReference), QualifierType);
+								
+								debug {
+									qualifiedInstanceTypeString = typeid(QualifierType).toString;
+								}
+								
+								resolvedThroughQualifier = true;
+								break;
+							}
+						}
+						
+						if (!resolvedThroughQualifier) {
+							qualifiedInstance = container.resolve!(typeof(memberReference));
+						}
+						
+						__traits(getMember, instance, member) = qualifiedInstance;
+						
+						debug {
+							auto qualifiedInstanceAddress = &qualifiedInstance;
+							writeln(format("DEBUG: Autowired instance [%s@%s] to [%s@%s].%s", qualifiedInstanceTypeString, qualifiedInstanceAddress, instanceType, instanceAddress, member));
+						}
 					}
+					
+					break;
 				}
 			}
 		}
diff --git a/test/poodinis/autowiretest.d b/test/poodinis/autowiretest.d
index 2b9ce0c..4b1815f 100644
--- a/test/poodinis/autowiretest.d
+++ b/test/poodinis/autowiretest.d
@@ -10,8 +10,7 @@ import poodinis.autowire;
 import std.exception;
 
 version(unittest) {
-	class ComponentA {
-	}
+	class ComponentA {}
 	
 	class ComponentB {
 		public @Autowire ComponentA componentA;
@@ -21,11 +20,9 @@ version(unittest) {
 		}
 	}
 	
-	interface InterfaceA {
-	}
+	interface InterfaceA {}
 	
-	class ComponentC : InterfaceA {
-	}
+	class ComponentC : InterfaceA {}
 	
 	class ComponentD {
 		public @Autowire InterfaceA componentC = null;
@@ -62,6 +59,24 @@ version(unittest) {
 		}
 	}
 	
+	class ComponentX : InterfaceA {}
+	
+	class MonkeyShine {
+		@Autowire
+		@Qualifier!ComponentX
+		public InterfaceA component;
+	}
+	
+	class BootstrapBootstrap {
+		@Autowire
+		@Qualifier!ComponentX
+		public InterfaceA componentX;
+		
+		@Autowire
+		@Qualifier!ComponentC
+		public InterfaceA componentC;
+	}
+	
 	// Test autowiring concrete type to existing instance
 	unittest {
 		auto container = new DependencyContainer();
@@ -132,4 +147,32 @@ version(unittest) {
 		
 		assert(componentDeclarationCocktail.componentA !is null, "Autowiring class with non-assignable declarations failed");
 	}
+	
+	// Test autowire class with qualifier
+	unittest {
+		auto container = new DependencyContainer();
+		container.register!(InterfaceA, ComponentC);
+		container.register!(InterfaceA, ComponentX);
+		auto componentX = container.resolve!(InterfaceA, ComponentX);
+		
+		auto monkeyShine = new MonkeyShine();
+		container.autowire(monkeyShine);
+		
+		assert(monkeyShine.component is componentX, "Autowiring class with qualifier failed");
+	}
+	
+	// Test autowire class with multiple qualifiers
+	unittest {
+		auto container = new DependencyContainer();
+		container.register!(InterfaceA, ComponentC);
+		container.register!(InterfaceA, ComponentX);
+		auto componentC = container.resolve!(InterfaceA, ComponentC);
+		auto componentX = container.resolve!(InterfaceA, ComponentX);
+		
+		auto bootstrapBootstrap = new BootstrapBootstrap();
+		container.autowire(bootstrapBootstrap);
+		
+		assert(bootstrapBootstrap.componentX is componentX, "Autowiring class with multiple qualifiers failed");
+		assert(bootstrapBootstrap.componentC is componentC, "Autowiring class with multiple qualifiers failed");
+	}
 }
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