fix derived JsonWriter performance

tethys-json · Jul 11, 2024 · c6b7731 · c6b7731
1 parent 127f2c6
commit c6b7731
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Showing 3 changed files with 40 additions and 37 deletions.
diff --git a/modules/core/src/main/scala-3/tethys/derivation/Derivation.scala b/modules/core/src/main/scala-3/tethys/derivation/Derivation.scala
@@ -3,7 +3,7 @@ package tethys.derivation
 import tethys.writers.tokens.TokenWriter
 import tethys.readers.FieldName
 import tethys.readers.ReaderError
-import tethys.{JsonConfig, JsonReader, JsonWriter, WriterBuilder, ReaderBuilder}
+import tethys.{JsonConfig, JsonReader, JsonWriter, JsonObjectWriter, WriterBuilder, ReaderBuilder}
 
 import scala.compiletime.{constValueTuple, summonInline}
 
@@ -12,9 +12,9 @@ object Derivation:
 
   inline def fieldJsonWriter[T, F]: JsonWriter[F] =
     ${ DerivationMacro.fieldJsonWriter[T, F] }
-
-  inline def parseWriterBuilder[T](inline config: WriterBuilder[T]): WriterBuilderParsed[T] =
-    ${ DerivationMacro.parseWriterBuilder[T]('{config}) }
+    
+  inline def deriveJsonWriterForProduct[T](inline config: WriterBuilder[T]): JsonObjectWriter[T] =
+    ${ DerivationMacro.deriveJsonWriterForProduct[T]('{config})}
 
   inline def parseReaderBuilder[T](inline config: ReaderBuilder[T]): ReaderBuilderParsed =
     ${ DerivationMacro.parseReaderBuilder[T]('{config})}
@@ -30,28 +30,43 @@ object Derivation:
 private[derivation]
 object DerivationMacro:
   import scala.quoted.*
-
-  def parseWriterBuilder[T: Type](config: Expr[WriterBuilder[T]])(using quotes: Quotes): Expr[WriterBuilderParsed[T]] =
+  
+  def deriveJsonWriterForProduct[T: Type](config: Expr[WriterBuilder[T]])(using quotes: Quotes): Expr[JsonObjectWriter[T]] =
     val utils = new ConfigurationMacroUtils
     import utils.quotes.reflect.*
-    '{
-      WriterBuilderParsed(
-        ${
-          Expr.ofList(
-            utils.prepareWriterProductFields[T](config).map { field =>
-              field.tpe.asType match
-                case '[fieldType] => '{
-                  WriterBuilderParsed.Field(
-                    label = ${ field.label },
-                    function = (value: T) => ${ field.value('{ value }.asTerm).asExprOf[fieldType] },
-                    writer = Derivation.fieldJsonWriter[T, fieldType]
-                  )
-                }
-            }
+
+    val fields = utils.prepareWriterProductFields(config)
+
+    def allocateWriters(types: List[TypeRepr]): (List[Statement], List[Ref]) = types.zipWithIndex.map { (tpe, idx) =>
+      tpe.asType match
+        case '[fieldType] =>
+          val term = ValDef(
+            Symbol.newVal(Symbol.spliceOwner, s"jsonWriter${tpe.typeSymbol.name}$idx", TypeRepr.of[JsonWriter[fieldType]], Flags.Lazy, Symbol.noSymbol),
+            Some('{ Derivation.fieldJsonWriter[T, fieldType] }.asTerm)
           )
-        }
-      )
-    }
+          (term, Ref(term.symbol))
+    }.unzip
+
+    val (writersStatements, writersRefs) = allocateWriters(fields.map(_.tpe))
+    Block(
+      writersStatements,
+      '{
+         new JsonObjectWriter[T]:
+           override def writeValues(value: T, tokenWriter: TokenWriter): Unit =
+             $ {
+               Expr.block(
+                 fields.zip(writersRefs).map { (field, writer) =>
+                   field.tpe.asType match
+                     case '[f] =>
+                       '{ ${ writer.asExprOf[JsonWriter[f]] }
+                         .write(${ field.label }, ${ field.value('{ value }.asTerm).asExprOf[f] }, tokenWriter) }
+                 },
+                 '{}
+               )
+             }
+      }.asTerm
+    ).asExprOf[JsonObjectWriter[T]]
+
 
   def fieldJsonWriter[T: Type, F: Type](using quotes: Quotes): Expr[JsonWriter[F]] =
     val utils = new ConfigurationMacroUtils
@@ -62,7 +77,7 @@ object DerivationMacro:
       tpe.asType match
         case '[fieldType] =>
           val term = ValDef(
-            Symbol.newVal(Symbol.spliceOwner, s"jsonWriter$idx", TypeRepr.of[JsonWriter[fieldType]], Flags.Lazy, Symbol.noSymbol),
+            Symbol.newVal(Symbol.spliceOwner, s"jsonWriter${tpe.typeSymbol.name}$idx", TypeRepr.of[JsonWriter[fieldType]], Flags.Lazy, Symbol.noSymbol),
             Some('{ JsonObjectWriterDerivation.summonOrDeriveJsonWriterForField[T, fieldType] }.asTerm)
           )
           (term, Ref(term.symbol))

diff --git a/modules/core/src/main/scala-3/tethys/derivation/JsonObjectWriterDerivation.scala b/modules/core/src/main/scala-3/tethys/derivation/JsonObjectWriterDerivation.scala
@@ -9,13 +9,7 @@ import scala.compiletime.{constValueTuple, erasedValue, summonFrom, summonInline
 private[tethys] trait JsonObjectWriterDerivation:
 
   inline def derived[A](inline config: WriterBuilder[A])(using mirror: Mirror.ProductOf[A]) =
-    new JsonObjectWriter[A]:
-      lazy val configuration: WriterBuilderParsed[A] = Derivation.parseWriterBuilder[A](config)
-
-      override def writeValues(value: A, tokenWriter: TokenWriter): Unit =
-        configuration.fields.foreach { field =>
-          field.writer.write(field.label, field.function(value), tokenWriter)
-        }
+    Derivation.deriveJsonWriterForProduct[A](config)
 
   inline def derived[A](inline config: JsonConfig[A])(using m: Mirror.SumOf[A]) =
     new JsonObjectWriter[A]:

diff --git a/modules/core/src/main/scala-3/tethys/derivation/WriterBuilderParsed.scala b/modules/core/src/main/scala-3/tethys/derivation/WriterBuilderParsed.scala
@@ -2,12 +2,6 @@ package tethys.derivation
 
 import tethys.JsonWriter
 
-private[derivation]
-case class WriterBuilderParsed[T](
-    fields: List[WriterBuilderParsed.Field[T, ?]]
-)
-
-
 private[derivation]
 object WriterBuilderParsed:
   case class Field[T, F](label: String, function: T => F, writer: JsonWriter[F])