Merge pull request #68 from wickwirew/enum-payload

Added ability to inspect enum payload type
wickwirew · Apr 9, 2020 · d563445 · d563445
2 parents 69886eb + f157fc7
commit d563445
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Showing 4 changed files with 48 additions and 3 deletions.
diff --git a/Sources/Runtime/Layouts/EnumTypeDescriptor.swift b/Sources/Runtime/Layouts/EnumTypeDescriptor.swift
@@ -12,7 +12,12 @@ struct EnumTypeDescriptor: TypeDescriptor {
     var accessFunctionPointer: RelativePointer<Int32, UnsafeRawPointer>
     var fieldDescriptor: RelativePointer<Int32, FieldDescriptor>
     var numPayloadCasesAndPayloadSizeOffset: UInt32
-    var numberOfFields: Int32 // numEmptyCases
+    var numEmptyCases: UInt32
     var offsetToTheFieldOffsetVector: RelativeVectorPointer<Int32, Int32>
     var genericContextHeader: TargetTypeGenericContextDescriptorHeader
+
+    var numberOfFields: Int32 {
+        get { return 0 }
+        set {   }
+    }
 }
diff --git a/Sources/Runtime/Metadata/EnumMetadata.swift b/Sources/Runtime/Metadata/EnumMetadata.swift
@@ -24,18 +24,36 @@ struct EnumMetadata: NominalMetadataType {
 
     var pointer: UnsafeMutablePointer<EnumMetadataLayout>
 
+    var numberOfPayloadCases: UInt32 {
+        return pointer.pointee.typeDescriptor.pointee.numPayloadCasesAndPayloadSizeOffset & 0x00FFFFFF
+    }
+
+    var numberOfCases: UInt32 {
+        return pointer.pointee.typeDescriptor.pointee.numEmptyCases + numberOfPayloadCases
+    }
+
     mutating func cases() -> [Case] {
         let fieldDescriptor = pointer.pointee.typeDescriptor.pointee
             .fieldDescriptor
             .advanced()
 
-        return (0..<fieldDescriptor.pointee.numFields).map { i in
+        let genericVector = genericArgumentVector()
+
+        return (0..<numberOfCases).map { i in
             let record = fieldDescriptor
                 .pointee
                 .fields
                 .element(at: Int(i))
 
-            return Case(name: record.pointee.fieldName())
+            return Case(
+                name: record.pointee.fieldName(),
+                payloadType: record.pointee._mangledTypeName.offset == 0
+                    ? nil
+                    : record.pointee.type(
+                        genericContext: pointer.pointee.typeDescriptor,
+                        genericArguments: genericVector
+                    )
+            )
         }
     }
 

diff --git a/Sources/Runtime/Models/Case.swift b/Sources/Runtime/Models/Case.swift
@@ -23,4 +23,5 @@
 /// An enum case
 public struct Case {
     public let name: String
+    public let payloadType: Any.Type?
 }
diff --git a/Tests/RuntimeTests/MetadataTests.swift b/Tests/RuntimeTests/MetadataTests.swift
@@ -196,6 +196,27 @@ class MetadataTests: XCTestCase {
         XCTAssert(info.cases[3].name == "d")
     }
 
+    func testEnumTestEnumWithPayload() {
+        enum Foo {
+            case a,b,c
+            case hasPayload(Int)
+            case hasTuplePayload(Bool, Int)
+        }
+
+        var md = EnumMetadata(type: Foo.self)
+        let info = md.toTypeInfo()
+
+        guard let hasPayload = info.cases.first(where: { $0.name == "hasPayload" }),
+            let hasTuplePayload = info.cases.first(where: { $0.name == "hasTuplePayload" }) else {
+                return XCTFail("Missing payload cases")
+        }
+
+        XCTAssertEqual(md.numberOfCases, 5)
+        XCTAssertEqual(md.numberOfPayloadCases, 2)
+        XCTAssert(hasPayload.payloadType == Int.self)
+        XCTAssert(hasTuplePayload.payloadType == (Bool, Int).self)
+    }
+
     func testOptional() throws {
         let info = try typeInfo(of: Double?.self)
         XCTAssert(info.cases[0].name == "some")