comparison src/capnproto-0.6.0/c++/src/capnp/dynamic.c++ @ 62:0994c39f1e94

Cap'n Proto v0.6 + build for OSX

+// Copyright (c) 2013-2014 Sandstorm Development Group, Inc. and contributors
+// Licensed under the MIT License:
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+#include "dynamic.h"
+#include <kj/debug.h>
+
+namespace capnp {
+
+namespace {
+
+bool hasDiscriminantValue(const schema::Field::Reader& reader) {
+  return reader.getDiscriminantValue() != schema::Field::NO_DISCRIMINANT;
+}
+
+template <typename T, typename U>
+KJ_ALWAYS_INLINE(T bitCast(U value));
+
+template <typename T, typename U>
+inline T bitCast(U value) {
+  static_assert(sizeof(T) == sizeof(U), "Size must match.");
+  return value;
+}
+template <>
+inline float bitCast<float, uint32_t>(uint32_t value) KJ_UNUSED;
+template <>
+inline float bitCast<float, uint32_t>(uint32_t value) {
+  float result;
+  memcpy(&result, &value, sizeof(value));
+  return result;
+}
+template <>
+inline double bitCast<double, uint64_t>(uint64_t value) KJ_UNUSED;
+template <>
+inline double bitCast<double, uint64_t>(uint64_t value) {
+  double result;
+  memcpy(&result, &value, sizeof(value));
+  return result;
+}
+template <>
+inline uint32_t bitCast<uint32_t, float>(float value) {
+  uint32_t result;
+  memcpy(&result, &value, sizeof(value));
+  return result;
+}
+template <>
+inline uint64_t bitCast<uint64_t, double>(double value) {
+  uint64_t result;
+  memcpy(&result, &value, sizeof(value));
+  return result;
+}
+
+ElementSize elementSizeFor(schema::Type::Which elementType) {
+  switch (elementType) {
+    case schema::Type::VOID: return ElementSize::VOID;
+    case schema::Type::BOOL: return ElementSize::BIT;
+    case schema::Type::INT8: return ElementSize::BYTE;
+    case schema::Type::INT16: return ElementSize::TWO_BYTES;
+    case schema::Type::INT32: return ElementSize::FOUR_BYTES;
+    case schema::Type::INT64: return ElementSize::EIGHT_BYTES;
+    case schema::Type::UINT8: return ElementSize::BYTE;
+    case schema::Type::UINT16: return ElementSize::TWO_BYTES;
+    case schema::Type::UINT32: return ElementSize::FOUR_BYTES;
+    case schema::Type::UINT64: return ElementSize::EIGHT_BYTES;
+    case schema::Type::FLOAT32: return ElementSize::FOUR_BYTES;
+    case schema::Type::FLOAT64: return ElementSize::EIGHT_BYTES;
+
+    case schema::Type::TEXT: return ElementSize::POINTER;
+    case schema::Type::DATA: return ElementSize::POINTER;
+    case schema::Type::LIST: return ElementSize::POINTER;
+    case schema::Type::ENUM: return ElementSize::TWO_BYTES;
+    case schema::Type::STRUCT: return ElementSize::INLINE_COMPOSITE;
+    case schema::Type::INTERFACE: return ElementSize::POINTER;
+    case schema::Type::ANY_POINTER: KJ_FAIL_ASSERT("List(AnyPointer) not supported."); break;
+  }
+
+  // Unknown type.  Treat it as zero-size.
+  return ElementSize::VOID;
+}
+
+inline _::StructSize structSizeFromSchema(StructSchema schema) {
+  auto node = schema.getProto().getStruct();
+  return _::StructSize(
+      bounded(node.getDataWordCount()) * WORDS,
+      bounded(node.getPointerCount()) * POINTERS);
+}
+
+}  // namespace
+
+// =======================================================================================
+
+kj::Maybe<EnumSchema::Enumerant> DynamicEnum::getEnumerant() const {
+  auto enumerants = schema.getEnumerants();
+  if (value < enumerants.size()) {
+    return enumerants[value];
+  } else {
+    return nullptr;
+  }
+}
+
+uint16_t DynamicEnum::asImpl(uint64_t requestedTypeId) const {
+  KJ_REQUIRE(requestedTypeId == schema.getProto().getId(),
+             "Type mismatch in DynamicEnum.as().") {
+    // use it anyway
+    break;
+  }
+  return value;
+}
+
+// =======================================================================================
+
+bool DynamicStruct::Reader::isSetInUnion(StructSchema::Field field) const {
+  auto proto = field.getProto();
+  if (hasDiscriminantValue(proto)) {
+    uint16_t discrim = reader.getDataField<uint16_t>(
+        assumeDataOffset(schema.getProto().getStruct().getDiscriminantOffset()));
+    return discrim == proto.getDiscriminantValue();
+  } else {
+    return true;
+  }
+}
+
+void DynamicStruct::Reader::verifySetInUnion(StructSchema::Field field) const {
+  KJ_REQUIRE(isSetInUnion(field),
+      "Tried to get() a union member which is not currently initialized.",
+      field.getProto().getName(), schema.getProto().getDisplayName());
+}
+
+bool DynamicStruct::Builder::isSetInUnion(StructSchema::Field field) {
+  auto proto = field.getProto();
+  if (hasDiscriminantValue(proto)) {
+    uint16_t discrim = builder.getDataField<uint16_t>(
+        assumeDataOffset(schema.getProto().getStruct().getDiscriminantOffset()));
+    return discrim == proto.getDiscriminantValue();
+  } else {
+    return true;
+  }
+}
+
+void DynamicStruct::Builder::verifySetInUnion(StructSchema::Field field) {
+  KJ_REQUIRE(isSetInUnion(field),
+      "Tried to get() a union member which is not currently initialized.",
+      field.getProto().getName(), schema.getProto().getDisplayName());
+}
+
+void DynamicStruct::Builder::setInUnion(StructSchema::Field field) {
+  // If a union member, set the discriminant to match.
+  auto proto = field.getProto();
+  if (hasDiscriminantValue(proto)) {
+    builder.setDataField<uint16_t>(
+        assumeDataOffset(schema.getProto().getStruct().getDiscriminantOffset()),
+        proto.getDiscriminantValue());
+  }
+}
+
+DynamicValue::Reader DynamicStruct::Reader::get(StructSchema::Field field) const {
+  KJ_REQUIRE(field.getContainingStruct() == schema, "`field` is not a field of this struct.");
+  verifySetInUnion(field);
+
+  auto type = field.getType();
+  auto proto = field.getProto();
+  switch (proto.which()) {
+    case schema::Field::SLOT: {
+      auto slot = proto.getSlot();
+
+      // Note that the default value might be "anyPointer" even if the type is some poniter type
+      // *other than* anyPointer. This happens with generics -- the field is actually a generic
+      // parameter that has been bound, but the default value was of course compiled without any
+      // binding available.
+      auto dval = slot.getDefaultValue();
+
+      switch (type.which()) {
+        case schema::Type::VOID:
+          return reader.getDataField<Void>(assumeDataOffset(slot.getOffset()));
+
+#define HANDLE_TYPE(discrim, titleCase, type) \
+        case schema::Type::discrim: \
+          return reader.getDataField<type>( \
+              assumeDataOffset(slot.getOffset()), \
+              bitCast<_::Mask<type>>(dval.get##titleCase()));
+
+        HANDLE_TYPE(BOOL, Bool, bool)
+        HANDLE_TYPE(INT8, Int8, int8_t)
+        HANDLE_TYPE(INT16, Int16, int16_t)
+        HANDLE_TYPE(INT32, Int32, int32_t)
+        HANDLE_TYPE(INT64, Int64, int64_t)
+        HANDLE_TYPE(UINT8, Uint8, uint8_t)
+        HANDLE_TYPE(UINT16, Uint16, uint16_t)
+        HANDLE_TYPE(UINT32, Uint32, uint32_t)
+        HANDLE_TYPE(UINT64, Uint64, uint64_t)
+        HANDLE_TYPE(FLOAT32, Float32, float)
+        HANDLE_TYPE(FLOAT64, Float64, double)
+
+#undef HANDLE_TYPE
+
+        case schema::Type::ENUM: {
+          uint16_t typedDval = dval.getEnum();
+          return DynamicEnum(type.asEnum(),
+              reader.getDataField<uint16_t>(assumeDataOffset(slot.getOffset()), typedDval));
+        }
+
+        case schema::Type::TEXT: {
+          Text::Reader typedDval = dval.isAnyPointer() ? Text::Reader() : dval.getText();
+          return reader.getPointerField(assumePointerOffset(slot.getOffset()))
+                       .getBlob<Text>(typedDval.begin(),
+                           assumeMax<MAX_TEXT_SIZE>(typedDval.size()) * BYTES);
+        }
+
+        case schema::Type::DATA: {
+          Data::Reader typedDval = dval.isAnyPointer() ? Data::Reader() : dval.getData();
+          return reader.getPointerField(assumePointerOffset(slot.getOffset()))
+                       .getBlob<Data>(typedDval.begin(),
+                           assumeBits<BLOB_SIZE_BITS>(typedDval.size()) * BYTES);
+        }
+
+        case schema::Type::LIST: {
+          auto elementType = type.asList().getElementType();
+          return DynamicList::Reader(type.asList(),
+              reader.getPointerField(assumePointerOffset(slot.getOffset()))
+                    .getList(elementSizeFor(elementType.which()), dval.isAnyPointer() ? nullptr :
+                        dval.getList().getAs<_::UncheckedMessage>()));
+        }
+
+        case schema::Type::STRUCT:
+          return DynamicStruct::Reader(type.asStruct(),
+              reader.getPointerField(assumePointerOffset(slot.getOffset()))
+                    .getStruct(dval.isAnyPointer() ? nullptr :
+                        dval.getStruct().getAs<_::UncheckedMessage>()));
+
+        case schema::Type::ANY_POINTER:
+          return AnyPointer::Reader(reader.getPointerField(assumePointerOffset(slot.getOffset())));
+
+        case schema::Type::INTERFACE:
+          return DynamicCapability::Client(type.asInterface(),
+              reader.getPointerField(assumePointerOffset(slot.getOffset())).getCapability());
+      }
+
+      KJ_UNREACHABLE;
+    }
+
+    case schema::Field::GROUP:
+      return DynamicStruct::Reader(type.asStruct(), reader);
+  }
+
+  KJ_UNREACHABLE;
+}
+
+DynamicValue::Builder DynamicStruct::Builder::get(StructSchema::Field field) {
+  KJ_REQUIRE(field.getContainingStruct() == schema, "`field` is not a field of this struct.");
+  verifySetInUnion(field);
+
+  auto proto = field.getProto();
+  auto type = field.getType();
+  switch (proto.which()) {
+    case schema::Field::SLOT: {
+      auto slot = proto.getSlot();
+
+      // Note that the default value might be "anyPointer" even if the type is some poniter type
+      // *other than* anyPointer. This happens with generics -- the field is actually a generic
+      // parameter that has been bound, but the default value was of course compiled without any
+      // binding available.
+      auto dval = slot.getDefaultValue();
+
+      switch (type.which()) {
+        case schema::Type::VOID:
+          return builder.getDataField<Void>(assumeDataOffset(slot.getOffset()));
+
+#define HANDLE_TYPE(discrim, titleCase, type) \
+        case schema::Type::discrim: \
+          return builder.getDataField<type>( \
+              assumeDataOffset(slot.getOffset()), \
+              bitCast<_::Mask<type>>(dval.get##titleCase()));
+
+        HANDLE_TYPE(BOOL, Bool, bool)
+        HANDLE_TYPE(INT8, Int8, int8_t)
+        HANDLE_TYPE(INT16, Int16, int16_t)
+        HANDLE_TYPE(INT32, Int32, int32_t)
+        HANDLE_TYPE(INT64, Int64, int64_t)
+        HANDLE_TYPE(UINT8, Uint8, uint8_t)
+        HANDLE_TYPE(UINT16, Uint16, uint16_t)
+        HANDLE_TYPE(UINT32, Uint32, uint32_t)
+        HANDLE_TYPE(UINT64, Uint64, uint64_t)
+        HANDLE_TYPE(FLOAT32, Float32, float)
+        HANDLE_TYPE(FLOAT64, Float64, double)
+
+#undef HANDLE_TYPE
+
+        case schema::Type::ENUM: {
+          uint16_t typedDval = dval.getEnum();
+          return DynamicEnum(type.asEnum(),
+              builder.getDataField<uint16_t>(assumeDataOffset(slot.getOffset()), typedDval));
+        }
+
+        case schema::Type::TEXT: {
+          Text::Reader typedDval = dval.isAnyPointer() ? Text::Reader() : dval.getText();
+          return builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                        .getBlob<Text>(typedDval.begin(),
+                            assumeMax<MAX_TEXT_SIZE>(typedDval.size()) * BYTES);
+        }
+
+        case schema::Type::DATA: {
+          Data::Reader typedDval = dval.isAnyPointer() ? Data::Reader() : dval.getData();
+          return builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                        .getBlob<Data>(typedDval.begin(),
+                            assumeBits<BLOB_SIZE_BITS>(typedDval.size()) * BYTES);
+        }
+
+        case schema::Type::LIST: {
+          ListSchema listType = type.asList();
+          if (listType.whichElementType() == schema::Type::STRUCT) {
+            return DynamicList::Builder(listType,
+                builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                       .getStructList(structSizeFromSchema(listType.getStructElementType()),
+                                      dval.isAnyPointer() ? nullptr :
+                                          dval.getList().getAs<_::UncheckedMessage>()));
+          } else {
+            return DynamicList::Builder(listType,
+                builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                       .getList(elementSizeFor(listType.whichElementType()),
+                                dval.isAnyPointer() ? nullptr :
+                                    dval.getList().getAs<_::UncheckedMessage>()));
+          }
+        }
+
+        case schema::Type::STRUCT: {
+          auto structSchema = type.asStruct();
+          return DynamicStruct::Builder(structSchema,
+              builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                     .getStruct(structSizeFromSchema(structSchema),
+                                dval.isAnyPointer() ? nullptr :
+                                    dval.getStruct().getAs<_::UncheckedMessage>()));
+        }
+
+        case schema::Type::ANY_POINTER:
+          return AnyPointer::Builder(
+              builder.getPointerField(assumePointerOffset(slot.getOffset())));
+
+        case schema::Type::INTERFACE:
+          return DynamicCapability::Client(type.asInterface(),
+              builder.getPointerField(assumePointerOffset(slot.getOffset())).getCapability());
+      }
+
+      KJ_UNREACHABLE;
+    }
+
+    case schema::Field::GROUP:
+      return DynamicStruct::Builder(type.asStruct(), builder);
+  }
+
+  KJ_UNREACHABLE;
+}
+
+DynamicValue::Pipeline DynamicStruct::Pipeline::get(StructSchema::Field field) {
+  KJ_REQUIRE(field.getContainingStruct() == schema, "`field` is not a field of this struct.");
+
+  auto proto = field.getProto();
+  KJ_REQUIRE(!hasDiscriminantValue(proto), "Can't pipeline on union members.");
+
+  auto type = field.getType();
+
+  switch (proto.which()) {
+    case schema::Field::SLOT: {
+      auto slot = proto.getSlot();
+
+      switch (type.which()) {
+        case schema::Type::STRUCT:
+          return DynamicStruct::Pipeline(type.asStruct(),
+              typeless.getPointerField(slot.getOffset()));
+
+        case schema::Type::INTERFACE:
+          return DynamicCapability::Client(type.asInterface(),
+              typeless.getPointerField(slot.getOffset()).asCap());
+
+        case schema::Type::ANY_POINTER:
+          switch (type.whichAnyPointerKind()) {
+            case schema::Type::AnyPointer::Unconstrained::STRUCT:
+              return DynamicStruct::Pipeline(StructSchema(),
+                  typeless.getPointerField(slot.getOffset()));
+            case schema::Type::AnyPointer::Unconstrained::CAPABILITY:
+              return DynamicCapability::Client(Capability::Client(
+                  typeless.getPointerField(slot.getOffset()).asCap()));
+            default:
+              KJ_FAIL_REQUIRE("Can only pipeline on struct and interface fields.");
+          }
+
+        default:
+          KJ_FAIL_REQUIRE("Can only pipeline on struct and interface fields.");
+      }
+
+      KJ_UNREACHABLE;
+    }
+
+    case schema::Field::GROUP:
+      return DynamicStruct::Pipeline(type.asStruct(), typeless.noop());
+  }
+
+  KJ_UNREACHABLE;
+}
+
+bool DynamicStruct::Reader::has(StructSchema::Field field) const {
+  KJ_REQUIRE(field.getContainingStruct() == schema, "`field` is not a field of this struct.");
+
+  auto proto = field.getProto();
+  if (hasDiscriminantValue(proto)) {
+    uint16_t discrim = reader.getDataField<uint16_t>(
+        assumeDataOffset(schema.getProto().getStruct().getDiscriminantOffset()));
+    if (discrim != proto.getDiscriminantValue()) {
+      // Field is not active in the union.
+      return false;
+    }
+  }
+
+  switch (proto.which()) {
+    case schema::Field::SLOT:
+      // Continue to below.
+      break;
+
+    case schema::Field::GROUP:
+      return true;
+  }
+
+  auto slot = proto.getSlot();
+  auto type = field.getType();
+
+  switch (type.which()) {
+    case schema::Type::VOID:
+    case schema::Type::BOOL:
+    case schema::Type::INT8:
+    case schema::Type::INT16:
+    case schema::Type::INT32:
+    case schema::Type::INT64:
+    case schema::Type::UINT8:
+    case schema::Type::UINT16:
+    case schema::Type::UINT32:
+    case schema::Type::UINT64:
+    case schema::Type::FLOAT32:
+    case schema::Type::FLOAT64:
+    case schema::Type::ENUM:
+      // Primitive types are always present.
+      return true;
+
+    case schema::Type::TEXT:
+    case schema::Type::DATA:
+    case schema::Type::LIST:
+    case schema::Type::STRUCT:
+    case schema::Type::ANY_POINTER:
+    case schema::Type::INTERFACE:
+      return !reader.getPointerField(assumePointerOffset(slot.getOffset())).isNull();
+  }
+
+  // Unknown type.  As far as we know, it isn't set.
+  return false;
+}
+
+kj::Maybe<StructSchema::Field> DynamicStruct::Reader::which() const {
+  auto structProto = schema.getProto().getStruct();
+  if (structProto.getDiscriminantCount() == 0) {
+    return nullptr;
+  }
+
+  uint16_t discrim = reader.getDataField<uint16_t>(
+      assumeDataOffset(structProto.getDiscriminantOffset()));
+  return schema.getFieldByDiscriminant(discrim);
+}
+
+kj::Maybe<StructSchema::Field> DynamicStruct::Builder::which() {
+  auto structProto = schema.getProto().getStruct();
+  if (structProto.getDiscriminantCount() == 0) {
+    return nullptr;
+  }
+
+  uint16_t discrim = builder.getDataField<uint16_t>(
+      assumeDataOffset(structProto.getDiscriminantOffset()));
+  return schema.getFieldByDiscriminant(discrim);
+}
+
+void DynamicStruct::Builder::set(StructSchema::Field field, const DynamicValue::Reader& value) {
+  KJ_REQUIRE(field.getContainingStruct() == schema, "`field` is not a field of this struct.");
+  setInUnion(field);
+
+  auto proto = field.getProto();
+  auto type = field.getType();
+  switch (proto.which()) {
+    case schema::Field::SLOT: {
+      auto slot = proto.getSlot();
+      auto dval = slot.getDefaultValue();
+
+      switch (type.which()) {
+        case schema::Type::VOID:
+          builder.setDataField<Void>(assumeDataOffset(slot.getOffset()), value.as<Void>());
+          return;
+
+#define HANDLE_TYPE(discrim, titleCase, type) \
+        case schema::Type::discrim: \
+          builder.setDataField<type>( \
+              assumeDataOffset(slot.getOffset()), value.as<type>(), \
+              bitCast<_::Mask<type> >(dval.get##titleCase())); \
+          return;
+
+        HANDLE_TYPE(BOOL, Bool, bool)
+        HANDLE_TYPE(INT8, Int8, int8_t)
+        HANDLE_TYPE(INT16, Int16, int16_t)
+        HANDLE_TYPE(INT32, Int32, int32_t)
+        HANDLE_TYPE(INT64, Int64, int64_t)
+        HANDLE_TYPE(UINT8, Uint8, uint8_t)
+        HANDLE_TYPE(UINT16, Uint16, uint16_t)
+        HANDLE_TYPE(UINT32, Uint32, uint32_t)
+        HANDLE_TYPE(UINT64, Uint64, uint64_t)
+        HANDLE_TYPE(FLOAT32, Float32, float)
+        HANDLE_TYPE(FLOAT64, Float64, double)
+
+#undef HANDLE_TYPE
+
+        case schema::Type::ENUM: {
+          uint16_t rawValue;
+          auto enumSchema = type.asEnum();
+          if (value.getType() == DynamicValue::TEXT) {
+            // Convert from text.
+            rawValue = enumSchema.getEnumerantByName(value.as<Text>()).getOrdinal();
+          } else if (value.getType() == DynamicValue::INT ||
+                     value.getType() == DynamicValue::UINT) {
+            rawValue = value.as<uint16_t>();
+          } else {
+            DynamicEnum enumValue = value.as<DynamicEnum>();
+            KJ_REQUIRE(enumValue.getSchema() == enumSchema, "Value type mismatch.") {
+              return;
+            }
+            rawValue = enumValue.getRaw();
+          }
+          builder.setDataField<uint16_t>(assumeDataOffset(slot.getOffset()), rawValue,
+                                         dval.getEnum());
+          return;
+        }
+
+        case schema::Type::TEXT:
+          builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                 .setBlob<Text>(value.as<Text>());
+          return;
+
+        case schema::Type::DATA:
+          builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                 .setBlob<Data>(value.as<Data>());
+          return;
+
+        case schema::Type::LIST: {
+          ListSchema listType = type.asList();
+          auto listValue = value.as<DynamicList>();
+          KJ_REQUIRE(listValue.getSchema() == listType, "Value type mismatch.") {
+            return;
+          }
+          builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                 .setList(listValue.reader);
+          return;
+        }
+
+        case schema::Type::STRUCT: {
+          auto structType = type.asStruct();
+          auto structValue = value.as<DynamicStruct>();
+          KJ_REQUIRE(structValue.getSchema() == structType, "Value type mismatch.") {
+            return;
+          }
+          builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                 .setStruct(structValue.reader);
+          return;
+        }
+
+        case schema::Type::ANY_POINTER: {
+          auto target = AnyPointer::Builder(
+              builder.getPointerField(assumePointerOffset(slot.getOffset())));
+
+          switch (value.getType()) {
+            case DynamicValue::Type::TEXT:
+              target.setAs<Text>(value.as<Text>());
+              return;
+            case DynamicValue::Type::DATA:
+              target.setAs<Data>(value.as<Data>());
+              return;
+            case DynamicValue::Type::LIST:
+              target.setAs<DynamicList>(value.as<DynamicList>());
+              return;
+            case DynamicValue::Type::STRUCT:
+              target.setAs<DynamicStruct>(value.as<DynamicStruct>());
+              return;
+            case DynamicValue::Type::CAPABILITY:
+              target.setAs<DynamicCapability>(value.as<DynamicCapability>());
+              return;
+            case DynamicValue::Type::ANY_POINTER:
+              target.set(value.as<AnyPointer>());
+              return;
+
+            case DynamicValue::Type::UNKNOWN:
+            case DynamicValue::Type::VOID:
+            case DynamicValue::Type::BOOL:
+            case DynamicValue::Type::INT:
+            case DynamicValue::Type::UINT:
+            case DynamicValue::Type::FLOAT:
+            case DynamicValue::Type::ENUM:
+              KJ_FAIL_ASSERT("Value type mismatch; expected AnyPointer");
+          }
+
+          KJ_UNREACHABLE;
+        }
+
+        case schema::Type::INTERFACE: {
+          auto interfaceType = type.asInterface();
+          auto capability = value.as<DynamicCapability>();
+          KJ_REQUIRE(capability.getSchema().extends(interfaceType), "Value type mismatch.") {
+            return;
+          }
+          builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                 .setCapability(kj::mv(capability.hook));
+          return;
+        }
+      }
+
+      KJ_UNREACHABLE;
+    }
+
+    case schema::Field::GROUP: {
+      auto src = value.as<DynamicStruct>();
+      auto dst = init(field).as<DynamicStruct>();
+
+      KJ_IF_MAYBE(unionField, src.which()) {
+        dst.set(*unionField, src.get(*unionField));
+      }
+
+      for (auto field: src.schema.getNonUnionFields()) {
+        if (src.has(field)) {
+          dst.set(field, src.get(field));
+        }
+      }
+    }
+  }
+
+  KJ_UNREACHABLE;
+}
+
+DynamicValue::Builder DynamicStruct::Builder::init(StructSchema::Field field) {
+  KJ_REQUIRE(field.getContainingStruct() == schema, "`field` is not a field of this struct.");
+  setInUnion(field);
+
+  auto proto = field.getProto();
+  auto type = field.getType();
+
+  switch (proto.which()) {
+    case schema::Field::SLOT: {
+      auto slot = proto.getSlot();
+      switch (type.which()) {
+        case schema::Type::STRUCT: {
+          auto subSchema = type.asStruct();
+          return DynamicStruct::Builder(subSchema,
+              builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                     .initStruct(structSizeFromSchema(subSchema)));
+        }
+        case schema::Type::ANY_POINTER: {
+          auto pointer = builder.getPointerField(assumePointerOffset(slot.getOffset()));
+          pointer.clear();
+          return AnyPointer::Builder(pointer);
+        }
+        default:
+          KJ_FAIL_REQUIRE("init() without a size is only valid for struct and object fields.");
+      }
+    }
+
+    case schema::Field::GROUP: {
+      clear(field);
+      return DynamicStruct::Builder(type.asStruct(), builder);
+    }
+  }
+
+  KJ_UNREACHABLE;
+}
+
+DynamicValue::Builder DynamicStruct::Builder::init(StructSchema::Field field, uint size) {
+  KJ_REQUIRE(field.getContainingStruct() == schema, "`field` is not a field of this struct.");
+  setInUnion(field);
+
+  auto proto = field.getProto();
+  auto type = field.getType();
+
+  switch (proto.which()) {
+    case schema::Field::SLOT: {
+      auto slot = proto.getSlot();
+      switch (type.which()) {
+        case schema::Type::LIST: {
+          auto listType = type.asList();
+          if (listType.whichElementType() == schema::Type::STRUCT) {
+            return DynamicList::Builder(listType,
+                builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                       .initStructList(bounded(size) * ELEMENTS,
+                                       structSizeFromSchema(listType.getStructElementType())));
+          } else {
+            return DynamicList::Builder(listType,
+                builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                       .initList(elementSizeFor(listType.whichElementType()),
+                                 bounded(size) * ELEMENTS));
+          }
+        }
+        case schema::Type::TEXT:
+          return builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                        .initBlob<Text>(bounded(size) * BYTES);
+        case schema::Type::DATA:
+          return builder.getPointerField(assumePointerOffset(slot.getOffset()))
+                        .initBlob<Data>(bounded(size) * BYTES);
+        default:
+          KJ_FAIL_REQUIRE(
+              "init() with size is only valid for list, text, or data fields.",
+              (uint)type.which());
+          break;
+      }
+    }
+
+    case schema::Field::GROUP:
+      KJ_FAIL_REQUIRE("init() with size is only valid for list, text, or data fields.");
+  }
+
+  KJ_UNREACHABLE;
+}
+
+void DynamicStruct::Builder::adopt(StructSchema::Field field, Orphan<DynamicValue>&& orphan) {
+  KJ_REQUIRE(field.getContainingStruct() == schema, "`field` is not a field of this struct.");
+  setInUnion(field);
+
+  auto proto = field.getProto();
+  switch (proto.which()) {
+    case schema::Field::SLOT: {
+      auto slot = proto.getSlot();
+      auto type = field.getType();
+
+      switch (type.which()) {
+        case schema::Type::VOID:
+        case schema::Type::BOOL:
+        case schema::Type::INT8:
+        case schema::Type::INT16:
+        case schema::Type::INT32:
+        case schema::Type::INT64:
+        case schema::Type::UINT8:
+        case schema::Type::UINT16:
+        case schema::Type::UINT32:
+        case schema::Type::UINT64:
+        case schema::Type::FLOAT32:
+        case schema::Type::FLOAT64:
+        case schema::Type::ENUM:
+          set(field, orphan.getReader());
+          return;
+
+        case schema::Type::TEXT:
+          KJ_REQUIRE(orphan.getType() == DynamicValue::TEXT, "Value type mismatch.");
+          break;
+
+        case schema::Type::DATA:
+          KJ_REQUIRE(orphan.getType() == DynamicValue::DATA, "Value type mismatch.");
+          break;
+
+        case schema::Type::LIST: {
+          ListSchema listType = type.asList();
+          KJ_REQUIRE(orphan.getType() == DynamicValue::LIST && orphan.listSchema == listType,
+                     "Value type mismatch.") {
+            return;
+          }
+          break;
+        }
+
+        case schema::Type::STRUCT: {
+          auto structType = type.asStruct();
+          KJ_REQUIRE(orphan.getType() == DynamicValue::STRUCT && orphan.structSchema == structType,
+                     "Value type mismatch.") {
+            return;
+          }
+          break;
+        }
+
+        case schema::Type::ANY_POINTER:
+          KJ_REQUIRE(orphan.getType() == DynamicValue::STRUCT ||
+                     orphan.getType() == DynamicValue::LIST ||
+                     orphan.getType() == DynamicValue::TEXT ||
+                     orphan.getType() == DynamicValue::DATA ||
+                     orphan.getType() == DynamicValue::CAPABILITY ||
+                     orphan.getType() == DynamicValue::ANY_POINTER,
+                     "Value type mismatch.") {
+            return;
+          }
+          break;
+
+        case schema::Type::INTERFACE: {
+          auto interfaceType = type.asInterface();
+          KJ_REQUIRE(orphan.getType() == DynamicValue::CAPABILITY &&
+                     orphan.interfaceSchema.extends(interfaceType),
+                     "Value type mismatch.") {
+            return;
+          }
+          break;
+        }
+      }
+
+      builder.getPointerField(assumePointerOffset(slot.getOffset())).adopt(kj::mv(orphan.builder));
+      return;
+    }
+
+    case schema::Field::GROUP:
+      // Have to transfer fields.
+      auto src = orphan.get().as<DynamicStruct>();
+      auto dst = init(field).as<DynamicStruct>();
+
+      KJ_REQUIRE(orphan.getType() == DynamicValue::STRUCT && orphan.structSchema == dst.getSchema(),
+                 "Value type mismatch.");
+
+      KJ_IF_MAYBE(unionField, src.which()) {
+        dst.adopt(*unionField, src.disown(*unionField));
+      }
+
+      for (auto field: src.schema.getNonUnionFields()) {
+        if (src.has(field)) {
+          dst.adopt(field, src.disown(field));
+        }
+      }
+
+      return;
+  }
+
+  KJ_UNREACHABLE;
+}
+
+Orphan<DynamicValue> DynamicStruct::Builder::disown(StructSchema::Field field) {
+  // We end up calling get(field) below, so we don't need to validate `field` here.
+
+  auto proto = field.getProto();
+  switch (proto.which()) {
+    case schema::Field::SLOT: {
+      auto slot = proto.getSlot();
+
+      switch (field.getType().which()) {
+        case schema::Type::VOID:
+        case schema::Type::BOOL:
+        case schema::Type::INT8:
+        case schema::Type::INT16:
+        case schema::Type::INT32:
+        case schema::Type::INT64:
+        case schema::Type::UINT8:
+        case schema::Type::UINT16:
+        case schema::Type::UINT32:
+        case schema::Type::UINT64:
+        case schema::Type::FLOAT32:
+        case schema::Type::FLOAT64:
+        case schema::Type::ENUM: {
+          auto result = Orphan<DynamicValue>(get(field), _::OrphanBuilder());
+          clear(field);
+          return kj::mv(result);
+        }
+
+        case schema::Type::TEXT:
+        case schema::Type::DATA:
+        case schema::Type::LIST:
+        case schema::Type::STRUCT:
+        case schema::Type::ANY_POINTER:
+        case schema::Type::INTERFACE: {
+          auto value = get(field);
+          return Orphan<DynamicValue>(
+              value, builder.getPointerField(assumePointerOffset(slot.getOffset())).disown());
+        }
+      }
+      KJ_UNREACHABLE;
+    }
+
+    case schema::Field::GROUP: {
+      // We have to allocate new space for the group, unfortunately.
+      auto src = get(field).as<DynamicStruct>();
+
+      Orphan<DynamicStruct> result =
+          Orphanage::getForMessageContaining(*this).newOrphan(src.getSchema());
+      auto dst = result.get();
+
+      KJ_IF_MAYBE(unionField, src.which()) {
+        dst.adopt(*unionField, src.disown(*unionField));
+      }
+
+      // We need to explicitly reset the union to its default field.
+      KJ_IF_MAYBE(unionField, src.schema.getFieldByDiscriminant(0)) {
+        src.clear(*unionField);
+      }
+
+      for (auto field: src.schema.getNonUnionFields()) {
+        if (src.has(field)) {
+          dst.adopt(field, src.disown(field));
+        }
+      }
+
+      return kj::mv(result);
+    }
+  }
+
+  KJ_UNREACHABLE;
+}
+
+void DynamicStruct::Builder::clear(StructSchema::Field field) {
+  KJ_REQUIRE(field.getContainingStruct() == schema, "`field` is not a field of this struct.");
+  setInUnion(field);
+
+  auto proto = field.getProto();
+  auto type = field.getType();
+  switch (proto.which()) {
+    case schema::Field::SLOT: {
+      auto slot = proto.getSlot();
+
+      switch (type.which()) {
+        case schema::Type::VOID:
+          builder.setDataField<Void>(assumeDataOffset(slot.getOffset()), VOID);
+          return;
+
+#define HANDLE_TYPE(discrim, type) \
+        case schema::Type::discrim: \
+          builder.setDataField<type>(assumeDataOffset(slot.getOffset()), 0); \
+          return;
+
+        HANDLE_TYPE(BOOL, bool)
+        HANDLE_TYPE(INT8, uint8_t)
+        HANDLE_TYPE(INT16, uint16_t)
+        HANDLE_TYPE(INT32, uint32_t)
+        HANDLE_TYPE(INT64, uint64_t)
+        HANDLE_TYPE(UINT8, uint8_t)
+        HANDLE_TYPE(UINT16, uint16_t)
+        HANDLE_TYPE(UINT32, uint32_t)
+        HANDLE_TYPE(UINT64, uint64_t)
+        HANDLE_TYPE(FLOAT32, uint32_t)
+        HANDLE_TYPE(FLOAT64, uint64_t)
+        HANDLE_TYPE(ENUM, uint16_t)
+
+#undef HANDLE_TYPE
+
+        case schema::Type::TEXT:
+        case schema::Type::DATA:
+        case schema::Type::LIST:
+        case schema::Type::STRUCT:
+        case schema::Type::ANY_POINTER:
+        case schema::Type::INTERFACE:
+          builder.getPointerField(assumePointerOffset(slot.getOffset())).clear();
+          return;
+      }
+
+      KJ_UNREACHABLE;
+    }
+
+    case schema::Field::GROUP: {
+      DynamicStruct::Builder group(type.asStruct(), builder);
+
+      // We clear the union field with discriminant 0 rather than the one that is set because
+      // we want the union to end up with its default field active.
+      KJ_IF_MAYBE(unionField, group.schema.getFieldByDiscriminant(0)) {
+        group.clear(*unionField);
+      }
+
+      for (auto subField: group.schema.getNonUnionFields()) {
+        group.clear(subField);
+      }
+      return;
+    }
+  }
+
+  KJ_UNREACHABLE;
+}
+
+DynamicValue::Reader DynamicStruct::Reader::get(kj::StringPtr name) const {
+  return get(schema.getFieldByName(name));
+}
+DynamicValue::Builder DynamicStruct::Builder::get(kj::StringPtr name) {
+  return get(schema.getFieldByName(name));
+}
+DynamicValue::Pipeline DynamicStruct::Pipeline::get(kj::StringPtr name) {
+  return get(schema.getFieldByName(name));
+}
+bool DynamicStruct::Reader::has(kj::StringPtr name) const {
+  return has(schema.getFieldByName(name));
+}
+bool DynamicStruct::Builder::has(kj::StringPtr name) {
+  return has(schema.getFieldByName(name));
+}
+void DynamicStruct::Builder::set(kj::StringPtr name, const DynamicValue::Reader& value) {
+  set(schema.getFieldByName(name), value);
+}
+void DynamicStruct::Builder::set(kj::StringPtr name,
+                                 std::initializer_list<DynamicValue::Reader> value) {
+  auto list = init(name, value.size()).as<DynamicList>();
+  uint i = 0;
+  for (auto element: value) {
+    list.set(i++, element);
+  }
+}
+DynamicValue::Builder DynamicStruct::Builder::init(kj::StringPtr name) {
+  return init(schema.getFieldByName(name));
+}
+DynamicValue::Builder DynamicStruct::Builder::init(kj::StringPtr name, uint size) {
+  return init(schema.getFieldByName(name), size);
+}
+void DynamicStruct::Builder::adopt(kj::StringPtr name, Orphan<DynamicValue>&& orphan) {
+  adopt(schema.getFieldByName(name), kj::mv(orphan));
+}
+Orphan<DynamicValue> DynamicStruct::Builder::disown(kj::StringPtr name) {
+  return disown(schema.getFieldByName(name));
+}
+void DynamicStruct::Builder::clear(kj::StringPtr name) {
+  clear(schema.getFieldByName(name));
+}
+
+// =======================================================================================
+
+DynamicValue::Reader DynamicList::Reader::operator[](uint index) const {
+  KJ_REQUIRE(index < size(), "List index out-of-bounds.");
+
+  switch (schema.whichElementType()) {
+#define HANDLE_TYPE(name, discrim, typeName) \
+    case schema::Type::discrim: \
+      return reader.getDataElement<typeName>(bounded(index) * ELEMENTS);
+
+    HANDLE_TYPE(void, VOID, Void)
+    HANDLE_TYPE(bool, BOOL, bool)
+    HANDLE_TYPE(int8, INT8, int8_t)
+    HANDLE_TYPE(int16, INT16, int16_t)
+    HANDLE_TYPE(int32, INT32, int32_t)
+    HANDLE_TYPE(int64, INT64, int64_t)
+    HANDLE_TYPE(uint8, UINT8, uint8_t)
+    HANDLE_TYPE(uint16, UINT16, uint16_t)
+    HANDLE_TYPE(uint32, UINT32, uint32_t)
+    HANDLE_TYPE(uint64, UINT64, uint64_t)
+    HANDLE_TYPE(float32, FLOAT32, float)
+    HANDLE_TYPE(float64, FLOAT64, double)
+#undef HANDLE_TYPE
+
+    case schema::Type::TEXT:
+      return reader.getPointerElement(bounded(index) * ELEMENTS)
+                   .getBlob<Text>(nullptr, ZERO * BYTES);
+    case schema::Type::DATA:
+      return reader.getPointerElement(bounded(index) * ELEMENTS)
+                   .getBlob<Data>(nullptr, ZERO * BYTES);
+
+    case schema::Type::LIST: {
+      auto elementType = schema.getListElementType();
+      return DynamicList::Reader(elementType,
+          reader.getPointerElement(bounded(index) * ELEMENTS)
+                .getList(elementSizeFor(elementType.whichElementType()), nullptr));
+    }
+
+    case schema::Type::STRUCT:
+      return DynamicStruct::Reader(schema.getStructElementType(),
+                                   reader.getStructElement(bounded(index) * ELEMENTS));
+
+    case schema::Type::ENUM:
+      return DynamicEnum(schema.getEnumElementType(),
+                         reader.getDataElement<uint16_t>(bounded(index) * ELEMENTS));
+
+    case schema::Type::ANY_POINTER:
+      return AnyPointer::Reader(reader.getPointerElement(bounded(index) * ELEMENTS));
+
+    case schema::Type::INTERFACE:
+      return DynamicCapability::Client(schema.getInterfaceElementType(),
+                                       reader.getPointerElement(bounded(index) * ELEMENTS)
+                                             .getCapability());
+  }
+
+  return nullptr;
+}
+
+DynamicValue::Builder DynamicList::Builder::operator[](uint index) {
+  KJ_REQUIRE(index < size(), "List index out-of-bounds.");
+
+  switch (schema.whichElementType()) {
+#define HANDLE_TYPE(name, discrim, typeName) \
+    case schema::Type::discrim: \
+      return builder.getDataElement<typeName>(bounded(index) * ELEMENTS);
+
+    HANDLE_TYPE(void, VOID, Void)
+    HANDLE_TYPE(bool, BOOL, bool)
+    HANDLE_TYPE(int8, INT8, int8_t)
+    HANDLE_TYPE(int16, INT16, int16_t)
+    HANDLE_TYPE(int32, INT32, int32_t)
+    HANDLE_TYPE(int64, INT64, int64_t)
+    HANDLE_TYPE(uint8, UINT8, uint8_t)
+    HANDLE_TYPE(uint16, UINT16, uint16_t)
+    HANDLE_TYPE(uint32, UINT32, uint32_t)
+    HANDLE_TYPE(uint64, UINT64, uint64_t)
+    HANDLE_TYPE(float32, FLOAT32, float)
+    HANDLE_TYPE(float64, FLOAT64, double)
+#undef HANDLE_TYPE
+
+    case schema::Type::TEXT:
+      return builder.getPointerElement(bounded(index) * ELEMENTS)
+                    .getBlob<Text>(nullptr, ZERO * BYTES);
+    case schema::Type::DATA:
+      return builder.getPointerElement(bounded(index) * ELEMENTS)
+                    .getBlob<Data>(nullptr, ZERO * BYTES);
+
+    case schema::Type::LIST: {
+      ListSchema elementType = schema.getListElementType();
+      if (elementType.whichElementType() == schema::Type::STRUCT) {
+        return DynamicList::Builder(elementType,
+            builder.getPointerElement(bounded(index) * ELEMENTS)
+                   .getStructList(structSizeFromSchema(elementType.getStructElementType()),
+                                  nullptr));
+      } else {
+        return DynamicList::Builder(elementType,
+            builder.getPointerElement(bounded(index) * ELEMENTS)
+                   .getList(elementSizeFor(elementType.whichElementType()), nullptr));
+      }
+    }
+
+    case schema::Type::STRUCT:
+      return DynamicStruct::Builder(schema.getStructElementType(),
+                                    builder.getStructElement(bounded(index) * ELEMENTS));
+
+    case schema::Type::ENUM:
+      return DynamicEnum(schema.getEnumElementType(),
+                         builder.getDataElement<uint16_t>(bounded(index) * ELEMENTS));
+
+    case schema::Type::ANY_POINTER:
+      KJ_FAIL_ASSERT("List(AnyPointer) not supported.");
+      return nullptr;
+
+    case schema::Type::INTERFACE:
+      return DynamicCapability::Client(schema.getInterfaceElementType(),
+                                       builder.getPointerElement(bounded(index) * ELEMENTS)
+                                              .getCapability());
+  }
+
+  return nullptr;
+}
+
+void DynamicList::Builder::set(uint index, const DynamicValue::Reader& value) {
+  KJ_REQUIRE(index < size(), "List index out-of-bounds.") {
+    return;
+  }
+
+  switch (schema.whichElementType()) {
+#define HANDLE_TYPE(name, discrim, typeName) \
+    case schema::Type::discrim: \
+      builder.setDataElement<typeName>(bounded(index) * ELEMENTS, value.as<typeName>()); \
+      return;
+
+    HANDLE_TYPE(void, VOID, Void)
+    HANDLE_TYPE(bool, BOOL, bool)
+    HANDLE_TYPE(int8, INT8, int8_t)
+    HANDLE_TYPE(int16, INT16, int16_t)
+    HANDLE_TYPE(int32, INT32, int32_t)
+    HANDLE_TYPE(int64, INT64, int64_t)
+    HANDLE_TYPE(uint8, UINT8, uint8_t)
+    HANDLE_TYPE(uint16, UINT16, uint16_t)
+    HANDLE_TYPE(uint32, UINT32, uint32_t)
+    HANDLE_TYPE(uint64, UINT64, uint64_t)
+    HANDLE_TYPE(float32, FLOAT32, float)
+    HANDLE_TYPE(float64, FLOAT64, double)
+#undef HANDLE_TYPE
+
+    case schema::Type::TEXT:
+      builder.getPointerElement(bounded(index) * ELEMENTS).setBlob<Text>(value.as<Text>());
+      return;
+    case schema::Type::DATA:
+      builder.getPointerElement(bounded(index) * ELEMENTS).setBlob<Data>(value.as<Data>());
+      return;
+
+    case schema::Type::LIST: {
+      auto listValue = value.as<DynamicList>();
+      KJ_REQUIRE(listValue.getSchema() == schema.getListElementType(), "Value type mismatch.") {
+        return;
+      }
+      builder.getPointerElement(bounded(index) * ELEMENTS).setList(listValue.reader);
+      return;
+    }
+
+    case schema::Type::STRUCT: {
+      auto structValue = value.as<DynamicStruct>();
+      KJ_REQUIRE(structValue.getSchema() == schema.getStructElementType(), "Value type mismatch.") {
+        return;
+      }
+      builder.getStructElement(bounded(index) * ELEMENTS).copyContentFrom(structValue.reader);
+      return;
+    }
+
+    case schema::Type::ENUM: {
+      uint16_t rawValue;
+      if (value.getType() == DynamicValue::TEXT) {
+        // Convert from text.
+        rawValue = schema.getEnumElementType().getEnumerantByName(value.as<Text>()).getOrdinal();
+      } else {
+        DynamicEnum enumValue = value.as<DynamicEnum>();
+        KJ_REQUIRE(schema.getEnumElementType() == enumValue.getSchema(),
+                   "Type mismatch when using DynamicList::Builder::set().") {
+          return;
+        }
+        rawValue = enumValue.getRaw();
+      }
+      builder.setDataElement<uint16_t>(bounded(index) * ELEMENTS, rawValue);
+      return;
+    }
+
+    case schema::Type::ANY_POINTER:
+      KJ_FAIL_ASSERT("List(AnyPointer) not supported.") {
+        return;
+      }
+
+    case schema::Type::INTERFACE: {
+      auto capValue = value.as<DynamicCapability>();
+      KJ_REQUIRE(capValue.getSchema().extends(schema.getInterfaceElementType()),
+                 "Value type mismatch.") {
+        return;
+      }
+      builder.getPointerElement(bounded(index) * ELEMENTS).setCapability(kj::mv(capValue.hook));
+      return;
+    }
+  }
+
+  KJ_FAIL_REQUIRE("can't set element of unknown type", (uint)schema.whichElementType()) {
+    return;
+  }
+}
+
+DynamicValue::Builder DynamicList::Builder::init(uint index, uint size) {
+  KJ_REQUIRE(index < this->size(), "List index out-of-bounds.");
+
+  switch (schema.whichElementType()) {
+    case schema::Type::VOID:
+    case schema::Type::BOOL:
+    case schema::Type::INT8:
+    case schema::Type::INT16:
+    case schema::Type::INT32:
+    case schema::Type::INT64:
+    case schema::Type::UINT8:
+    case schema::Type::UINT16:
+    case schema::Type::UINT32:
+    case schema::Type::UINT64:
+    case schema::Type::FLOAT32:
+    case schema::Type::FLOAT64:
+    case schema::Type::ENUM:
+    case schema::Type::STRUCT:
+    case schema::Type::INTERFACE:
+      KJ_FAIL_REQUIRE("Expected a list or blob.");
+      return nullptr;
+
+    case schema::Type::TEXT:
+      return builder.getPointerElement(bounded(index) * ELEMENTS)
+                    .initBlob<Text>(bounded(size) * BYTES);
+
+    case schema::Type::DATA:
+      return builder.getPointerElement(bounded(index) * ELEMENTS)
+                    .initBlob<Data>(bounded(size) * BYTES);
+
+    case schema::Type::LIST: {
+      auto elementType = schema.getListElementType();
+
+      if (elementType.whichElementType() == schema::Type::STRUCT) {
+        return DynamicList::Builder(elementType,
+            builder.getPointerElement(bounded(index) * ELEMENTS)
+                   .initStructList(bounded(size) * ELEMENTS,
+                                   structSizeFromSchema(elementType.getStructElementType())));
+      } else {
+        return DynamicList::Builder(elementType,
+            builder.getPointerElement(bounded(index) * ELEMENTS)
+                   .initList(elementSizeFor(elementType.whichElementType()),
+                             bounded(size) * ELEMENTS));
+      }
+    }
+
+    case schema::Type::ANY_POINTER: {
+      KJ_FAIL_ASSERT("List(AnyPointer) not supported.");
+      return nullptr;
+    }
+  }
+
+  return nullptr;
+}
+
+void DynamicList::Builder::adopt(uint index, Orphan<DynamicValue>&& orphan) {
+  switch (schema.whichElementType()) {
+    case schema::Type::VOID:
+    case schema::Type::BOOL:
+    case schema::Type::INT8:
+    case schema::Type::INT16:
+    case schema::Type::INT32:
+    case schema::Type::INT64:
+    case schema::Type::UINT8:
+    case schema::Type::UINT16:
+    case schema::Type::UINT32:
+    case schema::Type::UINT64:
+    case schema::Type::FLOAT32:
+    case schema::Type::FLOAT64:
+    case schema::Type::ENUM:
+      set(index, orphan.getReader());
+      return;
+
+    case schema::Type::TEXT:
+      KJ_REQUIRE(orphan.getType() == DynamicValue::TEXT, "Value type mismatch.");
+      builder.getPointerElement(bounded(index) * ELEMENTS).adopt(kj::mv(orphan.builder));
+      return;
+
+    case schema::Type::DATA:
+      KJ_REQUIRE(orphan.getType() == DynamicValue::DATA, "Value type mismatch.");
+      builder.getPointerElement(bounded(index) * ELEMENTS).adopt(kj::mv(orphan.builder));
+      return;
+
+    case schema::Type::LIST: {
+      ListSchema elementType = schema.getListElementType();
+      KJ_REQUIRE(orphan.getType() == DynamicValue::LIST && orphan.listSchema == elementType,
+                 "Value type mismatch.");
+      builder.getPointerElement(bounded(index) * ELEMENTS).adopt(kj::mv(orphan.builder));
+      return;
+    }
+
+    case schema::Type::STRUCT: {
+      auto elementType = schema.getStructElementType();
+      KJ_REQUIRE(orphan.getType() == DynamicValue::STRUCT && orphan.structSchema == elementType,
+                 "Value type mismatch.");
+      builder.getStructElement(bounded(index) * ELEMENTS).transferContentFrom(
+          orphan.builder.asStruct(structSizeFromSchema(elementType)));
+      return;
+    }
+
+    case schema::Type::ANY_POINTER:
+      KJ_FAIL_ASSERT("List(AnyPointer) not supported.");
+
+    case schema::Type::INTERFACE: {
+      auto elementType = schema.getInterfaceElementType();
+      KJ_REQUIRE(orphan.getType() == DynamicValue::CAPABILITY &&
+                 orphan.interfaceSchema.extends(elementType),
+                 "Value type mismatch.");
+      builder.getPointerElement(bounded(index) * ELEMENTS).adopt(kj::mv(orphan.builder));
+      return;
+    }
+  }
+
+  KJ_UNREACHABLE;
+}
+
+Orphan<DynamicValue> DynamicList::Builder::disown(uint index) {
+  switch (schema.whichElementType()) {
+    case schema::Type::VOID:
+    case schema::Type::BOOL:
+    case schema::Type::INT8:
+    case schema::Type::INT16:
+    case schema::Type::INT32:
+    case schema::Type::INT64:
+    case schema::Type::UINT8:
+    case schema::Type::UINT16:
+    case schema::Type::UINT32:
+    case schema::Type::UINT64:
+    case schema::Type::FLOAT32:
+    case schema::Type::FLOAT64:
+    case schema::Type::ENUM: {
+      auto result = Orphan<DynamicValue>(operator[](index), _::OrphanBuilder());
+      switch (elementSizeFor(schema.whichElementType())) {
+        case ElementSize::VOID: break;
+        case ElementSize::BIT: builder.setDataElement<bool>(bounded(index) * ELEMENTS, false); break;
+        case ElementSize::BYTE: builder.setDataElement<uint8_t>(bounded(index) * ELEMENTS, 0); break;
+        case ElementSize::TWO_BYTES: builder.setDataElement<uint16_t>(bounded(index) * ELEMENTS, 0); break;
+        case ElementSize::FOUR_BYTES: builder.setDataElement<uint32_t>(bounded(index) * ELEMENTS, 0); break;
+        case ElementSize::EIGHT_BYTES: builder.setDataElement<uint64_t>(bounded(index) * ELEMENTS, 0);break;
+
+        case ElementSize::POINTER:
+        case ElementSize::INLINE_COMPOSITE:
+          KJ_UNREACHABLE;
+      }
+      return kj::mv(result);
+    }
+
+    case schema::Type::TEXT:
+    case schema::Type::DATA:
+    case schema::Type::LIST:
+    case schema::Type::ANY_POINTER:
+    case schema::Type::INTERFACE: {
+      auto value = operator[](index);
+      return Orphan<DynamicValue>(value, builder.getPointerElement(bounded(index) * ELEMENTS).disown());
+    }
+
+    case schema::Type::STRUCT: {
+      // We have to make a copy.
+      Orphan<DynamicStruct> result =
+          Orphanage::getForMessageContaining(*this).newOrphan(schema.getStructElementType());
+      auto element = builder.getStructElement(bounded(index) * ELEMENTS);
+      result.get().builder.transferContentFrom(element);
+      element.clearAll();
+      return kj::mv(result);
+    }
+  }
+  KJ_UNREACHABLE;
+}
+
+void DynamicList::Builder::copyFrom(std::initializer_list<DynamicValue::Reader> value) {
+  KJ_REQUIRE(value.size() == size(), "DynamicList::copyFrom() argument had different size.");
+  uint i = 0;
+  for (auto element: value) {
+    set(i++, element);
+  }
+}
+
+DynamicList::Reader DynamicList::Builder::asReader() const {
+  return DynamicList::Reader(schema, builder.asReader());
+}
+
+// =======================================================================================
+
+DynamicValue::Reader::Reader(ConstSchema constant): type(VOID) {
+  auto type = constant.getType();
+  auto value = constant.getProto().getConst().getValue();
+  switch (type.which()) {
+    case schema::Type::VOID: *this = capnp::VOID; break;
+    case schema::Type::BOOL: *this = value.getBool(); break;
+    case schema::Type::INT8: *this = value.getInt8(); break;
+    case schema::Type::INT16: *this = value.getInt16(); break;
+    case schema::Type::INT32: *this = value.getInt32(); break;
+    case schema::Type::INT64: *this = value.getInt64(); break;
+    case schema::Type::UINT8: *this = value.getUint8(); break;
+    case schema::Type::UINT16: *this = value.getUint16(); break;
+    case schema::Type::UINT32: *this = value.getUint32(); break;
+    case schema::Type::UINT64: *this = value.getUint64(); break;
+    case schema::Type::FLOAT32: *this = value.getFloat32(); break;
+    case schema::Type::FLOAT64: *this = value.getFloat64(); break;
+    case schema::Type::TEXT: *this = value.getText(); break;
+    case schema::Type::DATA: *this = value.getData(); break;
+
+    case schema::Type::ENUM:
+      *this = DynamicEnum(type.asEnum(), value.getEnum());
+      break;
+
+    case schema::Type::STRUCT:
+      *this = value.getStruct().getAs<DynamicStruct>(type.asStruct());
+      break;
+
+    case schema::Type::LIST:
+      *this = value.getList().getAs<DynamicList>(type.asList());
+      break;
+
+    case schema::Type::ANY_POINTER:
+      *this = value.getAnyPointer();
+      break;
+
+    case schema::Type::INTERFACE:
+      KJ_FAIL_ASSERT("Constants can't have interface type.");
+  }
+}
+
+DynamicValue::Reader::Reader(const Reader& other) {
+  switch (other.type) {
+    case UNKNOWN:
+    case VOID:
+    case BOOL:
+    case INT:
+    case UINT:
+    case FLOAT:
+    case TEXT:
+    case DATA:
+    case LIST:
+    case ENUM:
+    case STRUCT:
+    case ANY_POINTER:
+      KJ_ASSERT_CAN_MEMCPY(Text::Reader);
+      KJ_ASSERT_CAN_MEMCPY(Data::Reader);
+      KJ_ASSERT_CAN_MEMCPY(DynamicList::Reader);
+      KJ_ASSERT_CAN_MEMCPY(DynamicEnum);
+      KJ_ASSERT_CAN_MEMCPY(DynamicStruct::Reader);
+      KJ_ASSERT_CAN_MEMCPY(AnyPointer::Reader);
+      break;
+
+    case CAPABILITY:
+      type = CAPABILITY;
+      kj::ctor(capabilityValue, other.capabilityValue);
+      return;
+  }
+
+  memcpy(this, &other, sizeof(*this));
+}
+DynamicValue::Reader::Reader(Reader&& other) noexcept {
+  switch (other.type) {
+    case UNKNOWN:
+    case VOID:
+    case BOOL:
+    case INT:
+    case UINT:
+    case FLOAT:
+    case TEXT:
+    case DATA:
+    case LIST:
+    case ENUM:
+    case STRUCT:
+    case ANY_POINTER:
+      KJ_ASSERT_CAN_MEMCPY(Text::Reader);
+      KJ_ASSERT_CAN_MEMCPY(Data::Reader);
+      KJ_ASSERT_CAN_MEMCPY(DynamicList::Reader);
+      KJ_ASSERT_CAN_MEMCPY(DynamicEnum);
+      KJ_ASSERT_CAN_MEMCPY(DynamicStruct::Reader);
+      KJ_ASSERT_CAN_MEMCPY(AnyPointer::Reader);
+      break;
+
+    case CAPABILITY:
+      type = CAPABILITY;
+      kj::ctor(capabilityValue, kj::mv(other.capabilityValue));
+      return;
+  }
+
+  memcpy(this, &other, sizeof(*this));
+}
+DynamicValue::Reader::~Reader() noexcept(false) {
+  if (type == CAPABILITY) {
+    kj::dtor(capabilityValue);
+  }
+}
+
+DynamicValue::Reader& DynamicValue::Reader::operator=(const Reader& other) {
+  if (type == CAPABILITY) {
+    kj::dtor(capabilityValue);
+  }
+  kj::ctor(*this, other);
+  return *this;
+}
+DynamicValue::Reader& DynamicValue::Reader::operator=(Reader&& other) {
+  if (type == CAPABILITY) {
+    kj::dtor(capabilityValue);
+  }
+  kj::ctor(*this, kj::mv(other));
+  return *this;
+}
+
+DynamicValue::Builder::Builder(Builder& other) {
+  switch (other.type) {
+    case UNKNOWN:
+    case VOID:
+    case BOOL:
+    case INT:
+    case UINT:
+    case FLOAT:
+    case TEXT:
+    case DATA:
+    case LIST:
+    case ENUM:
+    case STRUCT:
+    case ANY_POINTER:
+      // Unfortunately canMemcpy() doesn't work on these types due to the use of
+      // DisallowConstCopy, but __has_trivial_destructor should detect if any of these types
+      // become non-trivial.
+      static_assert(__has_trivial_destructor(Text::Builder) &&
+                    __has_trivial_destructor(Data::Builder) &&
+                    __has_trivial_destructor(DynamicList::Builder) &&
+                    __has_trivial_destructor(DynamicEnum) &&
+                    __has_trivial_destructor(DynamicStruct::Builder) &&
+                    __has_trivial_destructor(AnyPointer::Builder),
+                    "Assumptions here don't hold.");
+      break;
+
+    case CAPABILITY:
+      type = CAPABILITY;
+      kj::ctor(capabilityValue, other.capabilityValue);
+      return;
+  }
+
+  memcpy(this, &other, sizeof(*this));
+}
+DynamicValue::Builder::Builder(Builder&& other) noexcept {
+  switch (other.type) {
+    case UNKNOWN:
+    case VOID:
+    case BOOL:
+    case INT:
+    case UINT:
+    case FLOAT:
+    case TEXT:
+    case DATA:
+    case LIST:
+    case ENUM:
+    case STRUCT:
+    case ANY_POINTER:
+      // Unfortunately __has_trivial_copy doesn't work on these types due to the use of
+      // DisallowConstCopy, but __has_trivial_destructor should detect if any of these types
+      // become non-trivial.
+      static_assert(__has_trivial_destructor(Text::Builder) &&
+                    __has_trivial_destructor(Data::Builder) &&
+                    __has_trivial_destructor(DynamicList::Builder) &&
+                    __has_trivial_destructor(DynamicEnum) &&
+                    __has_trivial_destructor(DynamicStruct::Builder) &&
+                    __has_trivial_destructor(AnyPointer::Builder),
+                    "Assumptions here don't hold.");
+      break;
+
+    case CAPABILITY:
+      type = CAPABILITY;
+      kj::ctor(capabilityValue, kj::mv(other.capabilityValue));
+      return;
+  }
+
+  memcpy(this, &other, sizeof(*this));
+}
+DynamicValue::Builder::~Builder() noexcept(false) {
+  if (type == CAPABILITY) {
+    kj::dtor(capabilityValue);
+  }
+}
+
+DynamicValue::Builder& DynamicValue::Builder::operator=(Builder& other) {
+  if (type == CAPABILITY) {
+    kj::dtor(capabilityValue);
+  }
+  kj::ctor(*this, other);
+  return *this;
+}
+DynamicValue::Builder& DynamicValue::Builder::operator=(Builder&& other) {
+  if (type == CAPABILITY) {
+    kj::dtor(capabilityValue);
+  }
+  kj::ctor(*this, kj::mv(other));
+  return *this;
+}
+
+DynamicValue::Reader DynamicValue::Builder::asReader() const {
+  switch (type) {
+    case UNKNOWN: return Reader();
+    case VOID: return Reader(voidValue);
+    case BOOL: return Reader(boolValue);
+    case INT: return Reader(intValue);
+    case UINT: return Reader(uintValue);
+    case FLOAT: return Reader(floatValue);
+    case TEXT: return Reader(textValue.asReader());
+    case DATA: return Reader(dataValue.asReader());
+    case LIST: return Reader(listValue.asReader());
+    case ENUM: return Reader(enumValue);
+    case STRUCT: return Reader(structValue.asReader());
+    case CAPABILITY: return Reader(capabilityValue);
+    case ANY_POINTER: return Reader(anyPointerValue.asReader());
+  }
+  KJ_FAIL_ASSERT("Missing switch case.");
+  return Reader();
+}
+
+DynamicValue::Pipeline::Pipeline(Pipeline&& other) noexcept: type(other.type) {
+  switch (type) {
+    case UNKNOWN: break;
+    case STRUCT: kj::ctor(structValue, kj::mv(other.structValue)); break;
+    case CAPABILITY: kj::ctor(capabilityValue, kj::mv(other.capabilityValue)); break;
+    default:
+      KJ_LOG(ERROR, "Unexpected pipeline type.", (uint)type);
+      type = UNKNOWN;
+      break;
+  }
+}
+DynamicValue::Pipeline& DynamicValue::Pipeline::operator=(Pipeline&& other) {
+  kj::dtor(*this);
+  kj::ctor(*this, kj::mv(other));
+  return *this;
+}
+DynamicValue::Pipeline::~Pipeline() noexcept(false) {
+  switch (type) {
+    case UNKNOWN: break;
+    case STRUCT: kj::dtor(structValue); break;
+    case CAPABILITY: kj::dtor(capabilityValue); break;
+    default:
+      KJ_FAIL_ASSERT("Unexpected pipeline type.", (uint)type) { type = UNKNOWN; break; }
+      break;
+  }
+}
+
+namespace {
+
+template <typename T>
+T signedToUnsigned(long long value) {
+  KJ_REQUIRE(value >= 0 && T(value) == value, "Value out-of-range for requested type.", value) {
+    // Use it anyway.
+    break;
+  }
+  return value;
+}
+
+template <>
+uint64_t signedToUnsigned<uint64_t>(long long value) {
+  KJ_REQUIRE(value >= 0, "Value out-of-range for requested type.", value) {
+    // Use it anyway.
+    break;
+  }
+  return value;
+}
+
+template <typename T>
+T unsignedToSigned(unsigned long long value) {
+  KJ_REQUIRE(T(value) >= 0 && (unsigned long long)T(value) == value,
+             "Value out-of-range for requested type.", value) {
+    // Use it anyway.
+    break;
+  }
+  return value;
+}
+
+template <>
+int64_t unsignedToSigned<int64_t>(unsigned long long value) {
+  KJ_REQUIRE(int64_t(value) >= 0, "Value out-of-range for requested type.", value) {
+    // Use it anyway.
+    break;
+  }
+  return value;
+}
+
+template <typename T, typename U>
+T checkRoundTrip(U value) {
+  KJ_REQUIRE(T(value) == value, "Value out-of-range for requested type.", value) {
+    // Use it anyway.
+    break;
+  }
+  return value;
+}
+
+}  // namespace
+
+#define HANDLE_NUMERIC_TYPE(typeName, ifInt, ifUint, ifFloat) \
+typeName DynamicValue::Reader::AsImpl<typeName>::apply(const Reader& reader) { \
+  switch (reader.type) { \
+    case INT: \
+      return ifInt<typeName>(reader.intValue); \
+    case UINT: \
+      return ifUint<typeName>(reader.uintValue); \
+    case FLOAT: \
+      return ifFloat<typeName>(reader.floatValue); \
+    default: \
+      KJ_FAIL_REQUIRE("Value type mismatch.") { \
+        return 0; \
+      } \
+  } \
+} \
+typeName DynamicValue::Builder::AsImpl<typeName>::apply(Builder& builder) { \
+  switch (builder.type) { \
+    case INT: \
+      return ifInt<typeName>(builder.intValue); \
+    case UINT: \
+      return ifUint<typeName>(builder.uintValue); \
+    case FLOAT: \
+      return ifFloat<typeName>(builder.floatValue); \
+    default: \
+      KJ_FAIL_REQUIRE("Value type mismatch.") { \
+        return 0; \
+      } \
+  } \
+}
+
+HANDLE_NUMERIC_TYPE(int8_t, checkRoundTrip, unsignedToSigned, checkRoundTrip)
+HANDLE_NUMERIC_TYPE(int16_t, checkRoundTrip, unsignedToSigned, checkRoundTrip)
+HANDLE_NUMERIC_TYPE(int32_t, checkRoundTrip, unsignedToSigned, checkRoundTrip)
+HANDLE_NUMERIC_TYPE(int64_t, kj::implicitCast, unsignedToSigned, checkRoundTrip)
+HANDLE_NUMERIC_TYPE(uint8_t, signedToUnsigned, checkRoundTrip, checkRoundTrip)
+HANDLE_NUMERIC_TYPE(uint16_t, signedToUnsigned, checkRoundTrip, checkRoundTrip)
+HANDLE_NUMERIC_TYPE(uint32_t, signedToUnsigned, checkRoundTrip, checkRoundTrip)
+HANDLE_NUMERIC_TYPE(uint64_t, signedToUnsigned, kj::implicitCast, checkRoundTrip)
+HANDLE_NUMERIC_TYPE(float, kj::implicitCast, kj::implicitCast, kj::implicitCast)
+HANDLE_NUMERIC_TYPE(double, kj::implicitCast, kj::implicitCast, kj::implicitCast)
+
+#undef HANDLE_NUMERIC_TYPE
+
+#define HANDLE_TYPE(name, discrim, typeName) \
+ReaderFor<typeName> DynamicValue::Reader::AsImpl<typeName>::apply(const Reader& reader) { \
+  KJ_REQUIRE(reader.type == discrim, "Value type mismatch.") { \
+    return ReaderFor<typeName>(); \
+  } \
+  return reader.name##Value; \
+} \
+BuilderFor<typeName> DynamicValue::Builder::AsImpl<typeName>::apply(Builder& builder) { \
+  KJ_REQUIRE(builder.type == discrim, "Value type mismatch."); \
+  return builder.name##Value; \
+}
+
+//HANDLE_TYPE(void, VOID, Void)
+HANDLE_TYPE(bool, BOOL, bool)
+
+HANDLE_TYPE(text, TEXT, Text)
+HANDLE_TYPE(list, LIST, DynamicList)
+HANDLE_TYPE(struct, STRUCT, DynamicStruct)
+HANDLE_TYPE(enum, ENUM, DynamicEnum)
+HANDLE_TYPE(anyPointer, ANY_POINTER, AnyPointer)
+
+#undef HANDLE_TYPE
+
+PipelineFor<DynamicStruct> DynamicValue::Pipeline::AsImpl<DynamicStruct>::apply(
+    Pipeline& pipeline) {
+  KJ_REQUIRE(pipeline.type == STRUCT, "Pipeline type mismatch.");
+  return kj::mv(pipeline.structValue);
+}
+
+ReaderFor<DynamicCapability> DynamicValue::Reader::AsImpl<DynamicCapability>::apply(
+    const Reader& reader) {
+  KJ_REQUIRE(reader.type == CAPABILITY, "Value type mismatch.") {
+    return DynamicCapability::Client();
+  }
+  return reader.capabilityValue;
+}
+BuilderFor<DynamicCapability> DynamicValue::Builder::AsImpl<DynamicCapability>::apply(
+    Builder& builder) {
+  KJ_REQUIRE(builder.type == CAPABILITY, "Value type mismatch.") {
+    return DynamicCapability::Client();
+  }
+  return builder.capabilityValue;
+}
+PipelineFor<DynamicCapability> DynamicValue::Pipeline::AsImpl<DynamicCapability>::apply(
+    Pipeline& pipeline) {
+  KJ_REQUIRE(pipeline.type == CAPABILITY, "Pipeline type mismatch.") {
+    return DynamicCapability::Client();
+  }
+  return kj::mv(pipeline.capabilityValue);
+}
+
+Data::Reader DynamicValue::Reader::AsImpl<Data>::apply(const Reader& reader) {
+  if (reader.type == TEXT) {
+    // Coerce text to data.
+    return reader.textValue.asBytes();
+  }
+  KJ_REQUIRE(reader.type == DATA, "Value type mismatch.") {
+    return Data::Reader();
+  }
+  return reader.dataValue;
+}
+Data::Builder DynamicValue::Builder::AsImpl<Data>::apply(Builder& builder) {
+  if (builder.type == TEXT) {
+    // Coerce text to data.
+    return builder.textValue.asBytes();
+  }
+  KJ_REQUIRE(builder.type == DATA, "Value type mismatch.") {
+    return BuilderFor<Data>();
+  }
+  return builder.dataValue;
+}
+
+// As in the header, HANDLE_TYPE(void, VOID, Void) crashes GCC 4.7.
+Void DynamicValue::Reader::AsImpl<Void>::apply(const Reader& reader) {
+  KJ_REQUIRE(reader.type == VOID, "Value type mismatch.") {
+    return Void();
+  }
+  return reader.voidValue;
+}
+Void DynamicValue::Builder::AsImpl<Void>::apply(Builder& builder) {
+  KJ_REQUIRE(builder.type == VOID, "Value type mismatch.") {
+    return Void();
+  }
+  return builder.voidValue;
+}
+
+// =======================================================================================
+
+namespace _ {  // private
+
+DynamicStruct::Reader PointerHelpers<DynamicStruct, Kind::OTHER>::getDynamic(
+    PointerReader reader, StructSchema schema) {
+  KJ_REQUIRE(!schema.getProto().getStruct().getIsGroup(),
+             "Cannot form pointer to group type.");
+  return DynamicStruct::Reader(schema, reader.getStruct(nullptr));
+}
+DynamicStruct::Builder PointerHelpers<DynamicStruct, Kind::OTHER>::getDynamic(
+    PointerBuilder builder, StructSchema schema) {
+  KJ_REQUIRE(!schema.getProto().getStruct().getIsGroup(),
+             "Cannot form pointer to group type.");
+  return DynamicStruct::Builder(schema, builder.getStruct(
+      structSizeFromSchema(schema), nullptr));
+}
+void PointerHelpers<DynamicStruct, Kind::OTHER>::set(
+    PointerBuilder builder, const DynamicStruct::Reader& value) {
+  KJ_REQUIRE(!value.schema.getProto().getStruct().getIsGroup(),
+             "Cannot form pointer to group type.");
+  builder.setStruct(value.reader);
+}
+DynamicStruct::Builder PointerHelpers<DynamicStruct, Kind::OTHER>::init(
+    PointerBuilder builder, StructSchema schema) {
+  KJ_REQUIRE(!schema.getProto().getStruct().getIsGroup(),
+             "Cannot form pointer to group type.");
+  return DynamicStruct::Builder(schema,
+      builder.initStruct(structSizeFromSchema(schema)));
+}
+
+DynamicList::Reader PointerHelpers<DynamicList, Kind::OTHER>::getDynamic(
+    PointerReader reader, ListSchema schema) {
+  return DynamicList::Reader(schema,
+      reader.getList(elementSizeFor(schema.whichElementType()), nullptr));
+}
+DynamicList::Builder PointerHelpers<DynamicList, Kind::OTHER>::getDynamic(
+    PointerBuilder builder, ListSchema schema) {
+  if (schema.whichElementType() == schema::Type::STRUCT) {
+    return DynamicList::Builder(schema,
+        builder.getStructList(
+            structSizeFromSchema(schema.getStructElementType()),
+            nullptr));
+  } else {
+    return DynamicList::Builder(schema,
+        builder.getList(elementSizeFor(schema.whichElementType()), nullptr));
+  }
+}
+void PointerHelpers<DynamicList, Kind::OTHER>::set(
+    PointerBuilder builder, const DynamicList::Reader& value) {
+  builder.setList(value.reader);
+}
+DynamicList::Builder PointerHelpers<DynamicList, Kind::OTHER>::init(
+    PointerBuilder builder, ListSchema schema, uint size) {
+  if (schema.whichElementType() == schema::Type::STRUCT) {
+    return DynamicList::Builder(schema,
+        builder.initStructList(bounded(size) * ELEMENTS,
+            structSizeFromSchema(schema.getStructElementType())));
+  } else {
+    return DynamicList::Builder(schema,
+        builder.initList(elementSizeFor(schema.whichElementType()), bounded(size) * ELEMENTS));
+  }
+}
+
+DynamicCapability::Client PointerHelpers<DynamicCapability, Kind::OTHER>::getDynamic(
+    PointerReader reader, InterfaceSchema schema) {
+  return DynamicCapability::Client(schema, reader.getCapability());
+}
+DynamicCapability::Client PointerHelpers<DynamicCapability, Kind::OTHER>::getDynamic(
+    PointerBuilder builder, InterfaceSchema schema) {
+  return DynamicCapability::Client(schema, builder.getCapability());
+}
+void PointerHelpers<DynamicCapability, Kind::OTHER>::set(
+    PointerBuilder builder, DynamicCapability::Client& value) {
+  builder.setCapability(value.hook->addRef());
+}
+void PointerHelpers<DynamicCapability, Kind::OTHER>::set(
+    PointerBuilder builder, DynamicCapability::Client&& value) {
+  builder.setCapability(kj::mv(value.hook));
+}
+
+}  // namespace _ (private)
+
+template <>
+void AnyPointer::Builder::adopt<DynamicValue>(Orphan<DynamicValue>&& orphan) {
+  switch (orphan.getType()) {
+    case DynamicValue::UNKNOWN:
+    case DynamicValue::VOID:
+    case DynamicValue::BOOL:
+    case DynamicValue::INT:
+    case DynamicValue::UINT:
+    case DynamicValue::FLOAT:
+    case DynamicValue::ENUM:
+      KJ_FAIL_REQUIRE("AnyPointer cannot adopt primitive (non-object) value.");
+
+    case DynamicValue::STRUCT:
+    case DynamicValue::LIST:
+    case DynamicValue::TEXT:
+    case DynamicValue::DATA:
+    case DynamicValue::CAPABILITY:
+    case DynamicValue::ANY_POINTER:
+      builder.adopt(kj::mv(orphan.builder));
+      break;
+  }
+}
+
+DynamicStruct::Reader::Reader(StructSchema schema, const _::OrphanBuilder& orphan)
+    : schema(schema), reader(orphan.asStructReader(structSizeFromSchema(schema))) {}
+DynamicStruct::Builder::Builder(StructSchema schema, _::OrphanBuilder& orphan)
+    : schema(schema), builder(orphan.asStruct(structSizeFromSchema(schema))) {}
+
+DynamicList::Reader::Reader(ListSchema schema, const _::OrphanBuilder& orphan)
+    : schema(schema), reader(orphan.asListReader(elementSizeFor(schema.whichElementType()))) {}
+DynamicList::Builder::Builder(ListSchema schema, _::OrphanBuilder& orphan)
+    : schema(schema), builder(schema.whichElementType() == schema::Type::STRUCT
+        ? orphan.asStructList(structSizeFromSchema(schema.getStructElementType()))
+        : orphan.asList(elementSizeFor(schema.whichElementType()))) {}
+
+// -------------------------------------------------------------------
+
+Orphan<DynamicStruct> Orphanage::newOrphan(StructSchema schema) const {
+  return Orphan<DynamicStruct>(
+      schema, _::OrphanBuilder::initStruct(arena, capTable, structSizeFromSchema(schema)));
+}
+
+Orphan<DynamicList> Orphanage::newOrphan(ListSchema schema, uint size) const {
+  if (schema.whichElementType() == schema::Type::STRUCT) {
+    return Orphan<DynamicList>(schema, _::OrphanBuilder::initStructList(
+        arena, capTable, bounded(size) * ELEMENTS,
+        structSizeFromSchema(schema.getStructElementType())));
+  } else {
+    return Orphan<DynamicList>(schema, _::OrphanBuilder::initList(
+        arena, capTable, bounded(size) * ELEMENTS,
+        elementSizeFor(schema.whichElementType())));
+  }
+}
+
+DynamicStruct::Builder Orphan<DynamicStruct>::get() {
+  return DynamicStruct::Builder(schema, builder.asStruct(structSizeFromSchema(schema)));
+}
+
+DynamicStruct::Reader Orphan<DynamicStruct>::getReader() const {
+  return DynamicStruct::Reader(schema, builder.asStructReader(structSizeFromSchema(schema)));
+}
+
+DynamicList::Builder Orphan<DynamicList>::get() {
+  if (schema.whichElementType() == schema::Type::STRUCT) {
+    return DynamicList::Builder(
+        schema, builder.asStructList(structSizeFromSchema(schema.getStructElementType())));
+  } else {
+    return DynamicList::Builder(
+        schema, builder.asList(elementSizeFor(schema.whichElementType())));
+  }
+}
+
+DynamicList::Reader Orphan<DynamicList>::getReader() const {
+  return DynamicList::Reader(
+      schema, builder.asListReader(elementSizeFor(schema.whichElementType())));
+}
+
+DynamicCapability::Client Orphan<DynamicCapability>::get() {
+  return DynamicCapability::Client(schema, builder.asCapability());
+}
+
+DynamicCapability::Client Orphan<DynamicCapability>::getReader() const {
+  return DynamicCapability::Client(schema, builder.asCapability());
+}
+
+Orphan<DynamicValue>::Orphan(DynamicValue::Builder value, _::OrphanBuilder&& builder)
+    : type(value.getType()), builder(kj::mv(builder)) {
+  switch (type) {
+    case DynamicValue::UNKNOWN: break;
+    case DynamicValue::VOID: voidValue = value.voidValue; break;
+    case DynamicValue::BOOL: boolValue = value.boolValue; break;
+    case DynamicValue::INT: intValue = value.intValue; break;
+    case DynamicValue::UINT: uintValue = value.uintValue; break;
+    case DynamicValue::FLOAT: floatValue = value.floatValue; break;
+    case DynamicValue::ENUM: enumValue = value.enumValue; break;
+
+    case DynamicValue::TEXT: break;
+    case DynamicValue::DATA: break;
+    case DynamicValue::LIST: listSchema = value.listValue.getSchema(); break;
+    case DynamicValue::STRUCT: structSchema = value.structValue.getSchema(); break;
+    case DynamicValue::CAPABILITY: interfaceSchema = value.capabilityValue.getSchema(); break;
+    case DynamicValue::ANY_POINTER: break;
+  }
+}
+
+DynamicValue::Builder Orphan<DynamicValue>::get() {
+  switch (type) {
+    case DynamicValue::UNKNOWN: return nullptr;
+    case DynamicValue::VOID: return voidValue;
+    case DynamicValue::BOOL: return boolValue;
+    case DynamicValue::INT: return intValue;
+    case DynamicValue::UINT: return uintValue;
+    case DynamicValue::FLOAT: return floatValue;
+    case DynamicValue::ENUM: return enumValue;
+
+    case DynamicValue::TEXT: return builder.asText();
+    case DynamicValue::DATA: return builder.asData();
+    case DynamicValue::LIST:
+      if (listSchema.whichElementType() == schema::Type::STRUCT) {
+        return DynamicList::Builder(listSchema,
+            builder.asStructList(structSizeFromSchema(listSchema.getStructElementType())));
+      } else {
+        return DynamicList::Builder(listSchema,
+            builder.asList(elementSizeFor(listSchema.whichElementType())));
+      }
+    case DynamicValue::STRUCT:
+      return DynamicStruct::Builder(structSchema,
+          builder.asStruct(structSizeFromSchema(structSchema)));
+    case DynamicValue::CAPABILITY:
+      return DynamicCapability::Client(interfaceSchema, builder.asCapability());
+    case DynamicValue::ANY_POINTER:
+      KJ_FAIL_REQUIRE("Can't get() an AnyPointer orphan; there is no underlying pointer to "
+                      "wrap in an AnyPointer::Builder.");
+  }
+  KJ_UNREACHABLE;
+}
+DynamicValue::Reader Orphan<DynamicValue>::getReader() const {
+  switch (type) {
+    case DynamicValue::UNKNOWN: return nullptr;
+    case DynamicValue::VOID: return voidValue;
+    case DynamicValue::BOOL: return boolValue;
+    case DynamicValue::INT: return intValue;
+    case DynamicValue::UINT: return uintValue;
+    case DynamicValue::FLOAT: return floatValue;
+    case DynamicValue::ENUM: return enumValue;
+
+    case DynamicValue::TEXT: return builder.asTextReader();
+    case DynamicValue::DATA: return builder.asDataReader();
+    case DynamicValue::LIST:
+      return DynamicList::Reader(listSchema,
+          builder.asListReader(elementSizeFor(listSchema.whichElementType())));
+    case DynamicValue::STRUCT:
+      return DynamicStruct::Reader(structSchema,
+          builder.asStructReader(structSizeFromSchema(structSchema)));
+    case DynamicValue::CAPABILITY:
+      return DynamicCapability::Client(interfaceSchema, builder.asCapability());
+    case DynamicValue::ANY_POINTER:
+      KJ_FAIL_ASSERT("Can't get() an AnyPointer orphan; there is no underlying pointer to "
+                     "wrap in an AnyPointer::Builder.");
+  }
+  KJ_UNREACHABLE;
+}
+
+template <>
+Orphan<AnyPointer> Orphan<DynamicValue>::releaseAs<AnyPointer>() {
+  KJ_REQUIRE(type == DynamicValue::ANY_POINTER, "Value type mismatch.");
+  type = DynamicValue::UNKNOWN;
+  return Orphan<AnyPointer>(kj::mv(builder));
+}
+template <>
+Orphan<DynamicStruct> Orphan<DynamicValue>::releaseAs<DynamicStruct>() {
+  KJ_REQUIRE(type == DynamicValue::STRUCT, "Value type mismatch.");
+  type = DynamicValue::UNKNOWN;
+  return Orphan<DynamicStruct>(structSchema, kj::mv(builder));
+}
+template <>
+Orphan<DynamicList> Orphan<DynamicValue>::releaseAs<DynamicList>() {
+  KJ_REQUIRE(type == DynamicValue::LIST, "Value type mismatch.");
+  type = DynamicValue::UNKNOWN;
+  return Orphan<DynamicList>(listSchema, kj::mv(builder));
+}
+
+template <>
+Orphan<DynamicValue> Orphanage::newOrphanCopy<DynamicValue::Reader>(
+    DynamicValue::Reader copyFrom) const {
+  switch (copyFrom.getType()) {
+    case DynamicValue::UNKNOWN: return nullptr;
+    case DynamicValue::VOID: return copyFrom.voidValue;
+    case DynamicValue::BOOL: return copyFrom.boolValue;
+    case DynamicValue::INT: return copyFrom.intValue;
+    case DynamicValue::UINT: return copyFrom.uintValue;
+    case DynamicValue::FLOAT: return copyFrom.floatValue;
+    case DynamicValue::ENUM: return copyFrom.enumValue;
+
+    case DynamicValue::TEXT: return newOrphanCopy(copyFrom.textValue);
+    case DynamicValue::DATA: return newOrphanCopy(copyFrom.dataValue);
+    case DynamicValue::LIST: return newOrphanCopy(copyFrom.listValue);
+    case DynamicValue::STRUCT: return newOrphanCopy(copyFrom.structValue);
+    case DynamicValue::CAPABILITY: return newOrphanCopy(copyFrom.capabilityValue);
+    case DynamicValue::ANY_POINTER: return newOrphanCopy(copyFrom.anyPointerValue);
+  }
+  KJ_UNREACHABLE;
+}
+
+}  // namespace capnp