feat(generic): better generic sealed trait log encoder (#79)

avast · Mar 30, 2020 · fbd1f16 · fbd1f16
1 parent 0424c93
commit fbd1f16
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Showing 3 changed files with 50 additions and 20 deletions.
diff --git a/generic/src/main/scala/slog4s/generic/internal/Common.scala b/generic/src/main/scala/slog4s/generic/internal/Common.scala
@@ -3,25 +3,46 @@ package slog4s.generic.internal
 import magnolia.{CaseClass, SealedTrait}
 import slog4s.{LogEncoder, StructureBuilder}
 
+private final class CaseClassEncoder[T](caseClass: CaseClass[LogEncoder, T])
+    extends LogEncoder[T] {
+  override def encode[O](
+      value: T
+  )(implicit structureBuilder: StructureBuilder[O]): O = {
+    if (caseClass.isObject) {
+      structureBuilder.string(caseClass.typeName.short)
+    } else {
+      structureBuilder.map(encodeFields(value))
+    }
+  }
+
+  def encodeSealedMember[O](
+      value: T
+  )(implicit structureBuilder: StructureBuilder[O]): O = {
+    if (caseClass.isObject) {
+      structureBuilder.string(caseClass.typeName.short)
+    } else {
+      structureBuilder.structure(
+        caseClass.typeName.short,
+        encodeFields(value)
+      )
+    }
+  }
+
+  private def encodeFields[O](
+      value: T
+  )(implicit structureBuilder: StructureBuilder[O]): Map[String, O] = {
+    val params = caseClass.parameters.map { param =>
+      param.label -> param.typeclass.encode(param.dereference(value))
+    }
+    params.toMap
+  }
+}
+
 private[generic] object Common {
   def combine[T](
       caseClass: CaseClass[LogEncoder, T]
-  ): LogEncoder[T] = {
-    new LogEncoder[T] {
-      override def encode[O](
-          value: T
-      )(implicit structureBuilder: StructureBuilder[O]): O = {
-        if (caseClass.isObject) {
-          structureBuilder.string(caseClass.typeName.short)
-        } else {
-          val params = caseClass.parameters.map { param =>
-            param.label -> param.typeclass.encode(param.dereference(value))
-          }
-          structureBuilder.structure(caseClass.typeName.short, params.toMap)
-        }
-      }
-    }
-  }
+  ): LogEncoder[T] = new CaseClassEncoder[T](caseClass)
+
   def dispatch[T](
       sealedTrait: SealedTrait[LogEncoder, T]
   ): LogEncoder[T] = {
@@ -30,7 +51,12 @@ private[generic] object Common {
           value: T
       )(implicit structureBuilder: StructureBuilder[O]): O = {
         sealedTrait.dispatch(value) { subtype =>
-          subtype.typeclass.encode(subtype.cast(value))
+          subtype.typeclass match {
+            case caseClassEncoder: CaseClassEncoder[subtype.SType] =>
+              caseClassEncoder.encodeSealedMember(subtype.cast(value))
+            case other => other.encode(subtype.cast(value))
+          }
+
         }
       }
     }

diff --git a/generic/src/test/scala/slog4s/generic/DerivationTest.scala b/generic/src/test/scala/slog4s/generic/DerivationTest.scala
@@ -75,7 +75,11 @@ class DerivationTest extends AnyFunSpec {
       }
       it("sealed trait") {
         import TestClasses.SealedTrait
-        test[SealedTrait](SealedTrait.Value(42), Map("value" -> 42))
+        test(SealedTrait.Value(42), Map("value" -> 42))
+        test[SealedTrait](
+          SealedTrait.Value(42),
+          Map("value" -> 42, "type" -> "Value")
+        )
       }
       it("sealed trait (case object)") {
         sealed trait Foo
@@ -103,7 +107,7 @@ class DerivationTest extends AnyFunSpec {
     override def string(value: String): Any = value
 
     override def structure(name: String, attributes: Map[String, Any]): Any =
-      attributes
+      attributes.updated("type", name)
 
     override def option(value: Option[Any]): Any = value.orNull
 

diff --git a/slf4j/src/main/scala/slog4s/slf4j/MarkerStructureBuilder.scala b/slf4j/src/main/scala/slog4s/slf4j/MarkerStructureBuilder.scala
@@ -17,7 +17,7 @@ private[slf4j] object MarkerStructureBuilder {
       override def string(value: String): Any = value
 
       override def structure(name: String, attributes: Map[String, Any]): Any =
-        attributes.asJava
+        (attributes.updated("type", name)).asJava
 
       override def option(value: Option[Any]): Any = value.orNull