This generates per-field specific code for {@link DeferredObjectCodec}s. Serialization occurs + * by either using a getter or a {@link VarHandle} to retrieve the field value, then applying logic + * that varies by type. + * + *
There's a similar division for deserialization, with the {@link + * AsyncDeserializationContext#deserialize} handling aribtrary objects. Deserialized child values + * are written to a builder object, generated in {@link DeferredObjectCodecGenerator} with all the + * required fields and setters. + */ +abstract class DeferredObjectCodecFieldGenerators { + + static FieldGenerator create( + Name name, + TypeMirror parameterType, + ClassName parentName, + int hierarchyLevel, + FieldAccessor accessor, + ProcessingEnvironment env) + throws SerializationProcessingException { + TypeName typeName = getErasure(parameterType, env); + switch (parameterType.getKind()) { + case ARRAY: + ArrayType arrayType = (ArrayType) parameterType; + TypeMirror componentType = arrayType.getComponentType(); + TypeKind componentKind = componentType.getKind(); + if (componentKind.isPrimitive()) { + return new PrimitiveArrayFieldGenerator( + name, parameterType, typeName, parentName, componentKind, hierarchyLevel, accessor); + } + if (componentKind.equals(TypeKind.ARRAY)) { + return new NestedArrayFieldGenerator( + name, + parameterType, + typeName, + parentName, + hierarchyLevel, + resolveBaseArrayComponentType(componentType).getKind(), + accessor); + } + return new ObjectArrayFieldGenerator( + name, + parameterType, + typeName, + parentName, + hierarchyLevel, + getErasure(componentType, env), + accessor); + case BOOLEAN: + return new BooleanFieldGenerator( + name, parameterType, typeName, parentName, hierarchyLevel, accessor); + case BYTE: + return new ByteFieldGenerator( + name, parameterType, typeName, parentName, hierarchyLevel, accessor); + case CHAR: + return new CharFieldGenerator( + name, parameterType, typeName, parentName, hierarchyLevel, accessor); + case DOUBLE: + return new DoubleFieldGenerator( + name, parameterType, typeName, parentName, hierarchyLevel, accessor); + case FLOAT: + return new FloatFieldGenerator( + name, parameterType, typeName, parentName, hierarchyLevel, accessor); + case INT: + return new IntFieldGenerator( + name, parameterType, typeName, parentName, hierarchyLevel, accessor); + case LONG: + return new LongFieldGenerator( + name, parameterType, typeName, parentName, hierarchyLevel, accessor); + case SHORT: + return new ShortFieldGenerator( + name, parameterType, typeName, parentName, hierarchyLevel, accessor); + case TYPEVAR: + case DECLARED: + return new ObjectFieldGenerator( + name, parameterType, typeName, parentName, hierarchyLevel, accessor); + default: + // There are other TypeKinds, for example, NONE, NULL, VOID and WILDCARD, (and more, + // depending on the JDK version), but none are known to occur in code that defines the type + // of a member variable. + throw new SerializationProcessingException( + env.getElementUtils().getTypeElement(parentName.canonicalName()), + "%s had field %s having unexpected type %s", + parentName, + name, + parameterType); + } + } + + /** Metadata needed to retrieve the field. */ + sealed interface FieldAccessor + permits DeferredObjectCodecFieldGenerators.GetterName, + DeferredObjectCodecFieldGenerators.FieldType {} + + /** Uses a getter method called {@code name} to retrieve the field. */ + record GetterName(String name) implements FieldAccessor {} + + /** + * Uses a {@link VarHandle} to retrieve a field with type {@code typeName}. + * + *
The type is a parameter required to construct the {@link VarHandle}. It must be tracked + * separately from the parameter field type because it can be a subclass. For example, an object + * could be constructed using a {@code List} that is turned into an {@link ImmutableList} by the + * constructor. + */ + record FieldType(TypeName typeName) implements FieldAccessor {} + + private abstract static class VarHandleFieldGenerator extends FieldGenerator { + private final FieldAccessor accessor; + + /** + * Generates the per-field serialization code based on {@link VarHandle} and {@link + * DeferredObjectCodec}. + * + *
As usual for {@link AutoCodec}, serializion is defined by an instantiator and this class + * handles serialization of one of the parameters of the instantiator. This class + * actually handles two different cases, retrieval using a {@link VarHandle} and retrieval using + * getters, determined by the {@code accessor} implementation. + * + * @param accessor metadata about how to retrieve the field. The type {@link FieldAccessor} is + * sealed with two possible implementations. {@code accessor} is a {@link GetterName} when + * using a getter and contains the name of the getter. {@code accessor} is a {@link + * FieldType} when using a {@link VarHandle}, and it contains the exact field type, as + * defined in the class. + */ + private VarHandleFieldGenerator( + Name parameterName, + TypeMirror type, + TypeName typeName, + ClassName parentName, + int hierarchyLevel, + FieldAccessor accessor) { + super(parameterName, type, typeName, parentName, hierarchyLevel); + this.accessor = checkNotNull(accessor); + } + + @Override + @Nullable + final String getGetterName() { + if (accessor instanceof GetterName getter) { + return getter.name(); + } + return null; + } + + @Override + final void generateHandleMember(TypeSpec.Builder classBuilder, MethodSpec.Builder constructor) { + switch (accessor) { + case GetterName unused -> {} // Using a getter. No VarHandle needed. + case FieldType fieldType -> { + classBuilder.addField(VarHandle.class, getHandleName(), Modifier.PRIVATE, Modifier.FINAL); + constructor.addStatement( + "this.$L = $L.findVarHandle($T.class, $S, $T.class)", + getHandleName(), + CONSTRUCTOR_LOOKUP_NAME + getHierarchyLevel(), + getParentName(), + getParameterName(), + fieldType.typeName()); + } + } + } + + final CodeBlock generateAccessor() { + var builder = CodeBlock.builder(); + switch (accessor) { + case GetterName getterName -> builder.add("obj.$L()", getterName.name()); + case FieldType fieldType -> + builder.add("($L) $L.get(obj)", fieldType.typeName(), getHandleName()); + } + return builder.build(); + } + } + + private static final class NestedArrayFieldGenerator extends VarHandleFieldGenerator { + private final String processorName; + + private NestedArrayFieldGenerator( + Name name, + TypeMirror type, + TypeName typeName, + ClassName parentName, + int hierarchyLevel, + TypeKind baseComponentKind, + FieldAccessor accessor) { + super(name, type, typeName, parentName, hierarchyLevel, accessor); + switch (baseComponentKind) { + case BOOLEAN: + case BYTE: + case CHAR: + case DOUBLE: + case FLOAT: + case INT: + case LONG: + case SHORT: + this.processorName = baseComponentKind.name() + "_ARRAY_PROCESSOR"; + break; + case DECLARED: + case TYPEVAR: + // See comments of `ArrayProcessor.OBJECT_ARRAY_PROCESSOR` to understand how it works for + // any type of object array. + this.processorName = "OBJECT_ARRAY_PROCESSOR"; + break; + default: + throw new IllegalStateException( + "Unexpected base array component kind " + + baseComponentKind + + " for array field " + + name + + " of type " + + type); + } + } + + /** + * The generated codec has a {@code Class} member variable with this name storing the class + * of the field. + */ + private String getTypeMemberName() { + return getNamePrefix() + "_type"; + } + + @Override + void generateAdditionalMemberVariables(TypeSpec.Builder builder) { + builder.addField( + // Specifies Class type. + ParameterizedTypeName.get( + ClassName.get(Class.class), WildcardTypeName.subtypeOf(Object.class)), + getTypeMemberName(), + Modifier.PRIVATE, + Modifier.FINAL); + } + + @Override + void generateConstructorCode(MethodSpec.Builder constructor) { + constructor.addStatement( + "this.$L = $T.class.getDeclaredField(\"$L\").getType()", + getTypeMemberName(), + getParentName(), + getParameterName()); + } + + @Override + void generateSerializeCode(MethodSpec.Builder serialize) { + serialize.addStatement( + "$T.$L.serialize(context, codedOut, $L, $L)", + ArrayProcessor.class, + processorName, + getTypeMemberName(), + generateAccessor()); + } + + @Override + void generateDeserializeCode(MethodSpec.Builder deserialize) { + deserialize.addStatement( + "$L.$L = ($T) $T.$L.deserialize(context, codedIn, $L)", + BUILDER_NAME, + getParameterName(), + getTypeName(), + ArrayProcessor.class, + processorName, + getTypeMemberName()); + } + } + + private static class PrimitiveArrayFieldGenerator extends VarHandleFieldGenerator { + private final TypeKind componentType; + + private PrimitiveArrayFieldGenerator( + Name name, + TypeMirror type, + TypeName typeName, + ClassName parentName, + TypeKind componentType, + int hierarchyLevel, + FieldAccessor accessor) { + super(name, type, typeName, parentName, hierarchyLevel, accessor); + this.componentType = componentType; + } + + private String getProcessorName() { + return componentType + "_ARRAY_PROCESSOR"; + } + + @Override + void generateSerializeCode(MethodSpec.Builder serialize) { + String objName = getNamePrefix() + "_obj"; + serialize + .addStatement("$T $L = $L", Object.class, objName, generateAccessor()) + .beginControlFlow("if ($L == null)", objName) + .addStatement("codedOut.writeInt32NoTag(0)") + .nextControlFlow("else") + .addStatement( + "$T.$L.serializeArrayData(codedOut, $L)", + ArrayProcessor.class, + getProcessorName(), + objName) + .endControlFlow(); + } + + @Override + void generateDeserializeCode(MethodSpec.Builder deserialize) { + String lengthName = getNamePrefix() + "_length"; + deserialize + .addStatement("int $L = codedIn.readInt32()", lengthName) + .beginControlFlow("if ($L > 0)", lengthName) + .addStatement("$L--", lengthName) + .addStatement( + "$L.$L = ($T) $T.$L.deserializeArrayData(codedIn, $L)", + BUILDER_NAME, + getParameterName(), + getTypeName(), + ArrayProcessor.class, + getProcessorName(), + lengthName) + .endControlFlow(); + } + } + + private static class ObjectArrayFieldGenerator extends VarHandleFieldGenerator { + private final TypeName componentTypeName; + + private ObjectArrayFieldGenerator( + Name name, + TypeMirror type, + TypeName typeName, + ClassName parentName, + int hierarchyLevel, + TypeName componentTypeName, + FieldAccessor accessor) { + super(name, type, typeName, parentName, hierarchyLevel, accessor); + this.componentTypeName = componentTypeName; + } + + @Override + void generateSerializeCode(MethodSpec.Builder serialize) { + String arrName = getNamePrefix() + "_arr"; + serialize + .addStatement("$T $L = $L", Object.class, arrName, generateAccessor()) + .beginControlFlow("if ($L == null)", arrName) + .addStatement("codedOut.writeInt32NoTag(0)") + .nextControlFlow("else") + .addStatement( + "$T.serializeObjectArray(context, codedOut, $L)", ArrayProcessor.class, arrName) + .endControlFlow(); + } + + @Override + void generateDeserializeCode(MethodSpec.Builder deserialize) { + String lengthName = getNamePrefix() + "_length"; + deserialize + .addStatement("int $L = codedIn.readInt32()", lengthName) + .beginControlFlow("if ($L > 0)", lengthName) + .addStatement("$L--", lengthName) + .addStatement( + "$L.$L = new $T[$L]", BUILDER_NAME, getParameterName(), componentTypeName, lengthName) + .addStatement( + "$T.deserializeObjectArray(context, codedIn, $L.$L, $L)", + ArrayProcessor.class, + BUILDER_NAME, + getParameterName(), + lengthName) + .endControlFlow(); + } + } + + private static final class BooleanFieldGenerator extends VarHandleFieldGenerator { + private BooleanFieldGenerator( + Name name, + TypeMirror type, + TypeName typeName, + ClassName parentName, + int hierarchyLevel, + FieldAccessor accessor) { + super(name, type, typeName, parentName, hierarchyLevel, accessor); + } + + @Override + void generateSerializeCode(MethodSpec.Builder serialize) { + serialize.addStatement("codedOut.writeBoolNoTag((boolean) $L)", generateAccessor()); + } + + @Override + void generateDeserializeCode(MethodSpec.Builder deserialize) { + deserialize.addStatement("$L.$L = codedIn.readBool()", BUILDER_NAME, getParameterName()); + } + } + + private static final class ByteFieldGenerator extends VarHandleFieldGenerator { + private ByteFieldGenerator( + Name name, + TypeMirror type, + TypeName typeName, + ClassName parentName, + int hierarchyLevel, + FieldAccessor accessor) { + super(name, type, typeName, parentName, hierarchyLevel, accessor); + } + + @Override + void generateSerializeCode(MethodSpec.Builder serialize) { + serialize.addStatement("codedOut.writeRawByte((byte) $L)", generateAccessor()); + } + + @Override + void generateDeserializeCode(MethodSpec.Builder deserialize) { + deserialize.addStatement("$L.$L = codedIn.readRawByte()", BUILDER_NAME, getParameterName()); + } + } + + private static final class CharFieldGenerator extends VarHandleFieldGenerator { + private CharFieldGenerator( + Name name, + TypeMirror type, + TypeName typeName, + ClassName parentName, + int hierarchyLevel, + FieldAccessor accessor) { + super(name, type, typeName, parentName, hierarchyLevel, accessor); + } + + @Override + void generateSerializeCode(MethodSpec.Builder serialize) { + serialize.addStatement( + "$T.writeChar(codedOut, (char) $L)", CodecHelpers.class, generateAccessor()); + } + + @Override + void generateDeserializeCode(MethodSpec.Builder deserialize) { + deserialize.addStatement( + "$L.$L = $T.readChar(codedIn)", BUILDER_NAME, getParameterName(), CodecHelpers.class); + } + } + + private static final class DoubleFieldGenerator extends VarHandleFieldGenerator { + private DoubleFieldGenerator( + Name name, + TypeMirror type, + TypeName typeName, + ClassName parentName, + int hierarchyLevel, + FieldAccessor accessor) { + super(name, type, typeName, parentName, hierarchyLevel, accessor); + } + + @Override + void generateSerializeCode(MethodSpec.Builder serialize) { + serialize.addStatement("codedOut.writeDoubleNoTag((double) $L)", generateAccessor()); + } + + @Override + void generateDeserializeCode(MethodSpec.Builder deserialize) { + deserialize.addStatement("$L.$L = codedIn.readDouble()", BUILDER_NAME, getParameterName()); + } + } + + private static final class FloatFieldGenerator extends VarHandleFieldGenerator { + private FloatFieldGenerator( + Name name, + TypeMirror type, + TypeName typeName, + ClassName parentName, + int hierarchyLevel, + FieldAccessor accessor) { + super(name, type, typeName, parentName, hierarchyLevel, accessor); + } + + @Override + void generateSerializeCode(MethodSpec.Builder serialize) { + serialize.addStatement("codedOut.writeFloatNoTag((float) $L)", generateAccessor()); + } + + @Override + void generateDeserializeCode(MethodSpec.Builder deserialize) { + deserialize.addStatement("$L.$L = codedIn.readFloat()", BUILDER_NAME, getParameterName()); + } + } + + private static final class IntFieldGenerator extends VarHandleFieldGenerator { + private IntFieldGenerator( + Name name, + TypeMirror type, + TypeName typeName, + ClassName parentName, + int hierarchyLevel, + FieldAccessor accessor) { + super(name, type, typeName, parentName, hierarchyLevel, accessor); + } + + @Override + void generateSerializeCode(MethodSpec.Builder serialize) { + serialize.addStatement("codedOut.writeInt32NoTag((int) $L)", generateAccessor()); + } + + @Override + void generateDeserializeCode(MethodSpec.Builder deserialize) { + deserialize.addStatement("$L.$L = codedIn.readInt32()", BUILDER_NAME, getParameterName()); + } + } + + private static final class LongFieldGenerator extends VarHandleFieldGenerator { + private LongFieldGenerator( + Name name, + TypeMirror type, + TypeName typeName, + ClassName parentName, + int hierarchyLevel, + FieldAccessor accessor) { + super(name, type, typeName, parentName, hierarchyLevel, accessor); + } + + @Override + void generateSerializeCode(MethodSpec.Builder serialize) { + serialize.addStatement("codedOut.writeInt64NoTag((long) $L)", generateAccessor()); + } + + @Override + void generateDeserializeCode(MethodSpec.Builder deserialize) { + deserialize.addStatement("$L.$L = codedIn.readInt64()", BUILDER_NAME, getParameterName()); + } + } + + private static final class ShortFieldGenerator extends VarHandleFieldGenerator { + private ShortFieldGenerator( + Name name, + TypeMirror type, + TypeName typeName, + ClassName parentName, + int hierarchyLevel, + FieldAccessor accessor) { + super(name, type, typeName, parentName, hierarchyLevel, accessor); + } + + @Override + void generateSerializeCode(MethodSpec.Builder serialize) { + serialize.addStatement( + "$T.writeShort(codedOut, (short) $L)", CodecHelpers.class, generateAccessor()); + } + + @Override + void generateDeserializeCode(MethodSpec.Builder deserialize) { + deserialize.addStatement( + "$L.$L = $T.readShort(codedIn)", BUILDER_NAME, getParameterName(), CodecHelpers.class); + } + } + + private static final class ObjectFieldGenerator extends VarHandleFieldGenerator { + private ObjectFieldGenerator( + Name name, + TypeMirror type, + TypeName typeName, + ClassName parentName, + int hierarchyLevel, + FieldAccessor accessor) { + super(name, type, typeName, parentName, hierarchyLevel, accessor); + } + + @Override + void generateSerializeCode(MethodSpec.Builder serialize) { + serialize.addStatement("context.serialize($L, codedOut)", generateAccessor()); + } + + @Override + void generateDeserializeCode(MethodSpec.Builder deserialize) { + deserialize.addStatement( + "context.deserialize(codedIn, $L, $L::$L)", + BUILDER_NAME, + BUILDER_TYPE_NAME, + makeSetterName(getParameterName())); + } + } +}