capnproto

dynamic.h (61638B)

---

 // 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.
 
 // This file defines classes that can be used to manipulate messages based on schemas that are not
 // known until runtime.  This is also useful for writing generic code that uses schemas to handle
 // arbitrary types in a generic way.
 //
 // Each of the classes defined here has a to() template method which converts an instance back to a
 // native type.  This method will throw an exception if the requested type does not match the
 // schema.  To convert native types to dynamic, use DynamicFactory.
 //
 // As always, underlying data is validated lazily, so you have to actually traverse the whole
 // message if you want to validate all content.
 
 #pragma once
 
 #include "schema.h"
 #include "layout.h"
 #include "message.h"
 #include "any.h"
 #include "capability.h"
 #include <kj/windows-sanity.h>  // work-around macro conflict with `VOID`
 
 CAPNP_BEGIN_HEADER
 
 namespace capnp {
 
 class MessageReader;
 class MessageBuilder;
 
 struct DynamicValue {
   DynamicValue() = delete;
 
   enum Type {
     UNKNOWN,
     // Means that the value has unknown type and content because it comes from a newer version of
     // the schema, or from a newer version of Cap'n Proto that has new features that this version
     // doesn't understand.
 
     VOID,
     BOOL,
     INT,
     UINT,
     FLOAT,
     TEXT,
     DATA,
     LIST,
     ENUM,
     STRUCT,
     CAPABILITY,
     ANY_POINTER
   };
 
   class Reader;
   class Builder;
   class Pipeline;
 };
 class DynamicEnum;
 struct DynamicStruct {
   DynamicStruct() = delete;
   class Reader;
   class Builder;
   class Pipeline;
 };
 struct DynamicList {
   DynamicList() = delete;
   class Reader;
   class Builder;
 };
 struct DynamicCapability {
   DynamicCapability() = delete;
   class Client;
   class Server;
 };
 template <> class Orphan<DynamicValue>;
 
 template <Kind k> struct DynamicTypeFor_;
 template <> struct DynamicTypeFor_<Kind::ENUM> { typedef DynamicEnum Type; };
 template <> struct DynamicTypeFor_<Kind::STRUCT> { typedef DynamicStruct Type; };
 template <> struct DynamicTypeFor_<Kind::LIST> { typedef DynamicList Type; };
 template <> struct DynamicTypeFor_<Kind::INTERFACE> { typedef DynamicCapability Type; };
 
 template <typename T>
 using DynamicTypeFor = typename DynamicTypeFor_<kind<T>()>::Type;
 
 template <typename T>
 ReaderFor<DynamicTypeFor<FromReader<T>>> toDynamic(T&& value);
 template <typename T>
 BuilderFor<DynamicTypeFor<FromBuilder<T>>> toDynamic(T&& value);
 template <typename T>
 DynamicTypeFor<TypeIfEnum<T>> toDynamic(T&& value);
 template <typename T>
 typename DynamicTypeFor<FromServer<T>>::Client toDynamic(kj::Own<T>&& value);
 
 namespace _ {  // private
 
 template <> struct Kind_<DynamicValue     > { static constexpr Kind kind = Kind::OTHER; };
 template <> struct Kind_<DynamicEnum      > { static constexpr Kind kind = Kind::OTHER; };
 template <> struct Kind_<DynamicStruct    > { static constexpr Kind kind = Kind::OTHER; };
 template <> struct Kind_<DynamicList      > { static constexpr Kind kind = Kind::OTHER; };
 template <> struct Kind_<DynamicCapability> { static constexpr Kind kind = Kind::OTHER; };
 
 }  // namespace _ (private)
 
 template <> inline constexpr Style style<DynamicValue     >() { return Style::POINTER;    }
 template <> inline constexpr Style style<DynamicEnum      >() { return Style::PRIMITIVE;  }
 template <> inline constexpr Style style<DynamicStruct    >() { return Style::STRUCT;     }
 template <> inline constexpr Style style<DynamicList      >() { return Style::POINTER;    }
 template <> inline constexpr Style style<DynamicCapability>() { return Style::CAPABILITY; }
 
 // -------------------------------------------------------------------
 
 class DynamicEnum {
 public:
   DynamicEnum() = default;
   inline DynamicEnum(EnumSchema::Enumerant enumerant)
       : schema(enumerant.getContainingEnum()), value(enumerant.getOrdinal()) {}
   inline DynamicEnum(EnumSchema schema, uint16_t value)
       : schema(schema), value(value) {}
 
   template <typename T, typename = kj::EnableIf<kind<T>() == Kind::ENUM>>
   inline DynamicEnum(T&& value): DynamicEnum(toDynamic(value)) {}
 
   template <typename T>
   inline T as() const { return static_cast<T>(asImpl(typeId<T>())); }
   // Cast to a native enum type.
 
   inline EnumSchema getSchema() const { return schema; }
 
   kj::Maybe<EnumSchema::Enumerant> getEnumerant() const;
   // Get which enumerant this enum value represents.  Returns nullptr if the numeric value does not
   // correspond to any enumerant in the schema -- this can happen if the data was built using a
   // newer schema that has more values defined.
 
   inline uint16_t getRaw() const { return value; }
   // Returns the raw underlying enum value.
 
 private:
   EnumSchema schema;
   uint16_t value;
 
   uint16_t asImpl(uint64_t requestedTypeId) const;
 
   friend struct DynamicStruct;
   friend struct DynamicList;
   friend struct DynamicValue;
   template <typename T>
   friend DynamicTypeFor<TypeIfEnum<T>> toDynamic(T&& value);
 };
 
 // -------------------------------------------------------------------
 
 enum class HasMode: uint8_t {
   // Specifies the meaning of "has(field)".
 
   NON_NULL,
   // "has(field)" only returns false if the field is a pointer and the pointer is null. This is the
   // default behavior.
 
   NON_DEFAULT
   // "has(field)" returns false if the field is set to its default value. This differs from
   // NON_NULL only in the handling of primitive values.
   //
   // "Equal to default value" is technically defined as the field value being encoded as all-zero
   // on the wire (since primitive values are XORed by their defined default value when encoded).
 };
 
 class DynamicStruct::Reader {
 public:
   typedef DynamicStruct Reads;
 
   Reader() = default;
 
   template <typename T, typename = kj::EnableIf<kind<FromReader<T>>() == Kind::STRUCT>>
   inline Reader(T&& value): Reader(toDynamic(value)) {}
 
   inline operator AnyStruct::Reader() const { return AnyStruct::Reader(reader); }
 
   inline MessageSize totalSize() const { return reader.totalSize().asPublic(); }
 
   template <typename T>
   typename T::Reader as() const;
   // Convert the dynamic struct to its compiled-in type.
 
   inline StructSchema getSchema() const { return schema; }
 
   DynamicValue::Reader get(StructSchema::Field field) const;
   // Read the given field value.
 
   bool has(StructSchema::Field field, HasMode mode = HasMode::NON_NULL) const;
   // Tests whether the given field is "present". If the field is a union member and is not the
   // active member, this always returns false. Otherwise, the field's value is interpreted
   // according to `mode`.
 
   kj::Maybe<StructSchema::Field> which() const;
   // If the struct contains an (unnamed) union, and the currently-active field within that union
   // is known, this returns that field.  Otherwise, it returns null.  In other words, this returns
   // null if there is no union present _or_ if the union's discriminant is set to an unrecognized
   // value.  This could happen in particular when receiving a message from a sender who has a
   // newer version of the protocol and is using a field of the union that you don't know about yet.
 
   DynamicValue::Reader get(kj::StringPtr name) const;
   bool has(kj::StringPtr name, HasMode mode = HasMode::NON_NULL) const;
   // Shortcuts to access fields by name.  These throw exceptions if no such field exists.
 
 private:
   StructSchema schema;
   _::StructReader reader;
 
   inline Reader(StructSchema schema, _::StructReader reader)
       : schema(schema), reader(reader) {}
   Reader(StructSchema schema, const _::OrphanBuilder& orphan);
 
   bool isSetInUnion(StructSchema::Field field) const;
   void verifySetInUnion(StructSchema::Field field) const;
   static DynamicValue::Reader getImpl(_::StructReader reader, StructSchema::Field field);
 
   template <typename T, Kind K>
   friend struct _::PointerHelpers;
   friend class DynamicStruct::Builder;
   friend struct DynamicList;
   friend class MessageReader;
   friend class MessageBuilder;
   template <typename T, ::capnp::Kind k>
   friend struct ::capnp::ToDynamic_;
   friend kj::StringTree _::structString(
       _::StructReader reader, const _::RawBrandedSchema& schema);
   friend class Orphanage;
   friend class Orphan<DynamicStruct>;
   friend class Orphan<DynamicValue>;
   friend class Orphan<AnyPointer>;
   friend class AnyStruct::Reader;
 };
 
 class DynamicStruct::Builder {
 public:
   typedef DynamicStruct Builds;
 
   Builder() = default;
   inline Builder(decltype(nullptr)) {}
 
   template <typename T, typename = kj::EnableIf<kind<FromBuilder<T>>() == Kind::STRUCT>>
   inline Builder(T&& value): Builder(toDynamic(value)) {}
 
   inline operator AnyStruct::Builder() { return AnyStruct::Builder(builder); }
 
   inline MessageSize totalSize() const { return asReader().totalSize(); }
 
   template <typename T>
   typename T::Builder as();
   // Cast to a particular struct type.
 
   inline StructSchema getSchema() const { return schema; }
 
   DynamicValue::Builder get(StructSchema::Field field);
   // Read the given field value.
 
   inline bool has(StructSchema::Field field, HasMode mode = HasMode::NON_NULL)
       { return asReader().has(field, mode); }
   // Tests whether the given field is "present". If the field is a union member and is not the
   // active member, this always returns false. Otherwise, the field's value is interpreted
   // according to `mode`.
 
   kj::Maybe<StructSchema::Field> which();
   // If the struct contains an (unnamed) union, and the currently-active field within that union
   // is known, this returns that field.  Otherwise, it returns null.  In other words, this returns
   // null if there is no union present _or_ if the union's discriminant is set to an unrecognized
   // value.  This could happen in particular when receiving a message from a sender who has a
   // newer version of the protocol and is using a field of the union that you don't know about yet.
 
   void set(StructSchema::Field field, const DynamicValue::Reader& value);
   // Set the given field value.
 
   DynamicValue::Builder init(StructSchema::Field field);
   DynamicValue::Builder init(StructSchema::Field field, uint size);
   // Init a struct, list, or blob field.
 
   void adopt(StructSchema::Field field, Orphan<DynamicValue>&& orphan);
   Orphan<DynamicValue> disown(StructSchema::Field field);
   // Adopt/disown.  This works even for non-pointer fields: adopt() becomes equivalent to set()
   // and disown() becomes like get() followed by clear().
 
   void clear(StructSchema::Field field);
   // Clear a field, setting it to its default value.  For pointer fields, this actually makes the
   // field null.
 
   DynamicValue::Builder get(kj::StringPtr name);
   bool has(kj::StringPtr name, HasMode mode = HasMode::NON_NULL);
   void set(kj::StringPtr name, const DynamicValue::Reader& value);
   void set(kj::StringPtr name, std::initializer_list<DynamicValue::Reader> value);
   DynamicValue::Builder init(kj::StringPtr name);
   DynamicValue::Builder init(kj::StringPtr name, uint size);
   void adopt(kj::StringPtr name, Orphan<DynamicValue>&& orphan);
   Orphan<DynamicValue> disown(kj::StringPtr name);
   void clear(kj::StringPtr name);
   // Shortcuts to access fields by name.  These throw exceptions if no such field exists.
 
   Reader asReader() const;
 
 private:
   StructSchema schema;
   _::StructBuilder builder;
 
   inline Builder(StructSchema schema, _::StructBuilder builder)
       : schema(schema), builder(builder) {}
   Builder(StructSchema schema, _::OrphanBuilder& orphan);
 
   bool isSetInUnion(StructSchema::Field field);
   void verifySetInUnion(StructSchema::Field field);
   void setInUnion(StructSchema::Field field);
 
   template <typename T, Kind k>
   friend struct _::PointerHelpers;
   friend struct DynamicList;
   friend class MessageReader;
   friend class MessageBuilder;
   template <typename T, ::capnp::Kind k>
   friend struct ::capnp::ToDynamic_;
   friend class Orphanage;
   friend class Orphan<DynamicStruct>;
   friend class Orphan<DynamicValue>;
   friend class Orphan<AnyPointer>;
   friend class AnyStruct::Builder;
 };
 
 class DynamicStruct::Pipeline {
 public:
   typedef DynamicStruct Pipelines;
 
   inline Pipeline(decltype(nullptr)): typeless(nullptr) {}
 
   template <typename T>
   typename T::Pipeline releaseAs();
   // Convert the dynamic pipeline to its compiled-in type.
 
   inline StructSchema getSchema() { return schema; }
 
   DynamicValue::Pipeline get(StructSchema::Field field);
   // Read the given field value.
 
   DynamicValue::Pipeline get(kj::StringPtr name);
   // Get by string name.
 
 private:
   StructSchema schema;
   AnyPointer::Pipeline typeless;
 
   inline explicit Pipeline(StructSchema schema, AnyPointer::Pipeline&& typeless)
       : schema(schema), typeless(kj::mv(typeless)) {}
 
   friend class Request<DynamicStruct, DynamicStruct>;
 };
 
 // -------------------------------------------------------------------
 
 class DynamicList::Reader {
 public:
   typedef DynamicList Reads;
 
   inline Reader(): reader(ElementSize::VOID) {}
 
   template <typename T, typename = kj::EnableIf<kind<FromReader<T>>() == Kind::LIST>>
   inline Reader(T&& value): Reader(toDynamic(value)) {}
 
   inline operator AnyList::Reader() const { return AnyList::Reader(reader); }
 
   template <typename T>
   typename T::Reader as() const;
   // Try to convert to any List<T>, Data, or Text.  Throws an exception if the underlying data
   // can't possibly represent the requested type.
 
   inline ListSchema getSchema() const { return schema; }
 
   inline uint size() const { return unbound(reader.size() / ELEMENTS); }
   DynamicValue::Reader operator[](uint index) const;
 
   typedef _::IndexingIterator<const Reader, DynamicValue::Reader> Iterator;
   inline Iterator begin() const { return Iterator(this, 0); }
   inline Iterator end() const { return Iterator(this, size()); }
 
 private:
   ListSchema schema;
   _::ListReader reader;
 
   Reader(ListSchema schema, _::ListReader reader): schema(schema), reader(reader) {}
   Reader(ListSchema schema, const _::OrphanBuilder& orphan);
 
   template <typename T, Kind k>
   friend struct _::PointerHelpers;
   friend struct DynamicStruct;
   friend class DynamicList::Builder;
   template <typename T, ::capnp::Kind k>
   friend struct ::capnp::ToDynamic_;
   friend class Orphanage;
   friend class Orphan<DynamicList>;
   friend class Orphan<DynamicValue>;
   friend class Orphan<AnyPointer>;
 };
 
 class DynamicList::Builder {
 public:
   typedef DynamicList Builds;
 
   inline Builder(): builder(ElementSize::VOID) {}
   inline Builder(decltype(nullptr)): builder(ElementSize::VOID) {}
 
   template <typename T, typename = kj::EnableIf<kind<FromBuilder<T>>() == Kind::LIST>>
   inline Builder(T&& value): Builder(toDynamic(value)) {}
 
   inline operator AnyList::Builder() { return AnyList::Builder(builder); }
 
   template <typename T>
   typename T::Builder as();
   // Try to convert to any List<T>, Data, or Text.  Throws an exception if the underlying data
   // can't possibly represent the requested type.
 
   inline ListSchema getSchema() const { return schema; }
 
   inline uint size() const { return unbound(builder.size() / ELEMENTS); }
   DynamicValue::Builder operator[](uint index);
   void set(uint index, const DynamicValue::Reader& value);
   DynamicValue::Builder init(uint index, uint size);
   void adopt(uint index, Orphan<DynamicValue>&& orphan);
   Orphan<DynamicValue> disown(uint index);
 
   typedef _::IndexingIterator<Builder, DynamicStruct::Builder> Iterator;
   inline Iterator begin() { return Iterator(this, 0); }
   inline Iterator end() { return Iterator(this, size()); }
 
   void copyFrom(std::initializer_list<DynamicValue::Reader> value);
 
   Reader asReader() const;
 
 private:
   ListSchema schema;
   _::ListBuilder builder;
 
   Builder(ListSchema schema, _::ListBuilder builder): schema(schema), builder(builder) {}
   Builder(ListSchema schema, _::OrphanBuilder& orphan);
 
   template <typename T, Kind k>
   friend struct _::PointerHelpers;
   friend struct DynamicStruct;
   template <typename T, ::capnp::Kind k>
   friend struct ::capnp::ToDynamic_;
   friend class Orphanage;
   template <typename T, Kind k>
   friend struct _::OrphanGetImpl;
   friend class Orphan<DynamicList>;
   friend class Orphan<DynamicValue>;
   friend class Orphan<AnyPointer>;
 };
 
 // -------------------------------------------------------------------
 
 class DynamicCapability::Client: public Capability::Client {
 public:
   typedef DynamicCapability Calls;
   typedef DynamicCapability Reads;
 
   Client() = default;
 
   template <typename T, typename = kj::EnableIf<kind<FromClient<T>>() == Kind::INTERFACE>>
   inline Client(T&& client);
 
   template <typename T, typename = kj::EnableIf<kj::canConvert<T*, DynamicCapability::Server*>()>>
   inline Client(kj::Own<T>&& server);
 
   template <typename T, typename = kj::EnableIf<kind<T>() == Kind::INTERFACE>>
   typename T::Client as();
   template <typename T, typename = kj::EnableIf<kind<T>() == Kind::INTERFACE>>
   typename T::Client releaseAs();
   // Convert to any client type.
 
   Client upcast(InterfaceSchema requestedSchema);
   // Upcast to a superclass.  Throws an exception if `schema` is not a superclass.
 
   inline InterfaceSchema getSchema() { return schema; }
 
   Request<DynamicStruct, DynamicStruct> newRequest(
       InterfaceSchema::Method method, kj::Maybe<MessageSize> sizeHint = nullptr);
   Request<DynamicStruct, DynamicStruct> newRequest(
       kj::StringPtr methodName, kj::Maybe<MessageSize> sizeHint = nullptr);
 
 private:
   InterfaceSchema schema;
 
   Client(InterfaceSchema schema, kj::Own<ClientHook>&& hook)
       : Capability::Client(kj::mv(hook)), schema(schema) {}
 
   template <typename T>
   inline Client(InterfaceSchema schema, kj::Own<T>&& server);
 
   friend struct Capability;
   friend struct DynamicStruct;
   friend struct DynamicList;
   friend struct DynamicValue;
   friend class Orphan<DynamicCapability>;
   friend class Orphan<DynamicValue>;
   friend class Orphan<AnyPointer>;
   template <typename T, Kind k>
   friend struct _::PointerHelpers;
 };
 
 class DynamicCapability::Server: public Capability::Server {
 public:
   typedef DynamicCapability Serves;
 
   Server(InterfaceSchema schema): schema(schema) {}
 
   virtual kj::Promise<void> call(InterfaceSchema::Method method,
                                  CallContext<DynamicStruct, DynamicStruct> context) = 0;
 
   DispatchCallResult dispatchCall(uint64_t interfaceId, uint16_t methodId,
                                   CallContext<AnyPointer, AnyPointer> context) override final;
 
   inline InterfaceSchema getSchema() const { return schema; }
 
 private:
   InterfaceSchema schema;
 };
 
 template <>
 class Request<DynamicStruct, DynamicStruct>: public DynamicStruct::Builder {
   // Specialization of `Request<T, U>` for DynamicStruct.
 
 public:
   inline Request(DynamicStruct::Builder builder, kj::Own<RequestHook>&& hook,
                  StructSchema resultSchema)
       : DynamicStruct::Builder(builder), hook(kj::mv(hook)), resultSchema(resultSchema) {}
 
   RemotePromise<DynamicStruct> send();
   // Send the call and return a promise for the results.
 
   kj::Promise<void> sendStreaming();
   // Use when the caller is aware that the response type is StreamResult and wants to invoke
   // streaming behavior. It is an error to call this if the response type is not StreamResult.
 
 private:
   kj::Own<RequestHook> hook;
   StructSchema resultSchema;
 
   friend class Capability::Client;
   friend struct DynamicCapability;
   template <typename, typename>
   friend class CallContext;
   friend class RequestHook;
 };
 
 template <>
 class CallContext<DynamicStruct, DynamicStruct>: public kj::DisallowConstCopy {
   // Wrapper around CallContextHook with a specific return type.
   //
   // Methods of this class may only be called from within the server's event loop, not from other
   // threads.
 
 public:
   explicit CallContext(CallContextHook& hook, StructSchema paramType, StructSchema resultType);
 
   DynamicStruct::Reader getParams();
   void releaseParams();
   DynamicStruct::Builder getResults(kj::Maybe<MessageSize> sizeHint = nullptr);
   DynamicStruct::Builder initResults(kj::Maybe<MessageSize> sizeHint = nullptr);
   void setResults(DynamicStruct::Reader value);
   void adoptResults(Orphan<DynamicStruct>&& value);
   Orphanage getResultsOrphanage(kj::Maybe<MessageSize> sizeHint = nullptr);
   template <typename SubParams>
   kj::Promise<void> tailCall(Request<SubParams, DynamicStruct>&& tailRequest);
   void allowCancellation();
 
   StructSchema getParamsType() const { return paramType; }
   StructSchema getResultsType() const { return resultType; }
 
 private:
   CallContextHook* hook;
   StructSchema paramType;
   StructSchema resultType;
 
   friend class DynamicCapability::Server;
 };
 
 // -------------------------------------------------------------------
 
 // Make sure ReaderFor<T> and BuilderFor<T> work for DynamicEnum, DynamicStruct, and
 // DynamicList, so that we can define DynamicValue::as().
 
 template <> struct ReaderFor_ <DynamicEnum, Kind::OTHER> { typedef DynamicEnum Type; };
 template <> struct BuilderFor_<DynamicEnum, Kind::OTHER> { typedef DynamicEnum Type; };
 template <> struct ReaderFor_ <DynamicStruct, Kind::OTHER> { typedef DynamicStruct::Reader Type; };
 template <> struct BuilderFor_<DynamicStruct, Kind::OTHER> { typedef DynamicStruct::Builder Type; };
 template <> struct ReaderFor_ <DynamicList, Kind::OTHER> { typedef DynamicList::Reader Type; };
 template <> struct BuilderFor_<DynamicList, Kind::OTHER> { typedef DynamicList::Builder Type; };
 template <> struct ReaderFor_ <DynamicCapability, Kind::OTHER> { typedef DynamicCapability::Client Type; };
 template <> struct BuilderFor_<DynamicCapability, Kind::OTHER> { typedef DynamicCapability::Client Type; };
 template <> struct PipelineFor_<DynamicCapability, Kind::OTHER> { typedef DynamicCapability::Client Type; };
 
 class DynamicValue::Reader {
 public:
   typedef DynamicValue Reads;
 
   inline Reader(decltype(nullptr) n = nullptr);  // UNKNOWN
   inline Reader(Void value);
   inline Reader(bool value);
   inline Reader(char value);
   inline Reader(signed char value);
   inline Reader(short value);
   inline Reader(int value);
   inline Reader(long value);
   inline Reader(long long value);
   inline Reader(unsigned char value);
   inline Reader(unsigned short value);
   inline Reader(unsigned int value);
   inline Reader(unsigned long value);
   inline Reader(unsigned long long value);
   inline Reader(float value);
   inline Reader(double value);
   inline Reader(const char* value);  // Text
   inline Reader(const Text::Reader& value);
   inline Reader(const Data::Reader& value);
   inline Reader(const DynamicList::Reader& value);
   inline Reader(DynamicEnum value);
   inline Reader(const DynamicStruct::Reader& value);
   inline Reader(const AnyPointer::Reader& value);
   inline Reader(DynamicCapability::Client& value);
   inline Reader(DynamicCapability::Client&& value);
   template <typename T, typename = kj::EnableIf<kj::canConvert<T*, DynamicCapability::Server*>()>>
   inline Reader(kj::Own<T>&& value);
   Reader(ConstSchema constant);
 
   template <typename T, typename = decltype(toDynamic(kj::instance<T>()))>
   inline Reader(T&& value): Reader(toDynamic(kj::mv(value))) {}
 
   Reader(const Reader& other);
   Reader(Reader&& other) noexcept;
   ~Reader() noexcept(false);
   Reader& operator=(const Reader& other);
   Reader& operator=(Reader&& other);
   // Unfortunately, we cannot use the implicit definitions of these since DynamicCapability is not
   // trivially copyable.
 
   template <typename T>
   inline ReaderFor<T> as() const { return AsImpl<T>::apply(*this); }
   // Use to interpret the value as some Cap'n Proto type.  Allowed types are:
   // - Void, bool, [u]int{8,16,32,64}_t, float, double, any enum:  Returns the raw value.
   // - Text, Data, AnyPointer, any struct type:  Returns the corresponding Reader.
   // - List<T> for any T listed above:  Returns List<T>::Reader.
   // - DynamicEnum:  Returns the corresponding type.
   // - DynamicStruct, DynamicList:  Returns the corresponding Reader.
   // - Any capability type, including DynamicCapability:  Returns the corresponding Client.
   // - DynamicValue:  Returns an identical Reader. Useful to avoid special-casing in generic code.
   //   (TODO(perf):  On GCC 4.8 / Clang 3.3, provide rvalue-qualified version that avoids
   //   refcounting.)
   //
   // DynamicValue allows various implicit conversions, mostly just to make the interface friendlier.
   // - Any integer can be converted to any other integer type so long as the actual value is within
   //   the new type's range.
   // - Floating-point types can be converted to integers as long as no information would be lost
   //   in the conversion.
   // - Integers can be converted to floating points.  This may lose information, but won't throw.
   // - Float32/Float64 can be converted between each other.  Converting Float64 -> Float32 may lose
   //   information, but won't throw.
   // - Text can be converted to an enum, if the Text matches one of the enumerant names (but not
   //   vice-versa).
   // - Capabilities can be upcast (cast to a supertype), but not downcast.
   //
   // Any other conversion attempt will throw an exception.
 
   inline Type getType() const { return type; }
   // Get the type of this value.
 
 private:
   Type type;
 
   union {
     Void voidValue;
     bool boolValue;
     int64_t intValue;
     uint64_t uintValue;
     double floatValue;
     Text::Reader textValue;
     Data::Reader dataValue;
     DynamicList::Reader listValue;
     DynamicEnum enumValue;
     DynamicStruct::Reader structValue;
     AnyPointer::Reader anyPointerValue;
 
     mutable DynamicCapability::Client capabilityValue;
     // Declared mutable because `Client`s normally cannot be const.
 
     // Warning:  Copy/move constructors assume all these types are trivially copyable except
     //   Capability.
   };
 
   template <typename T, Kind kind = kind<T>()> struct AsImpl;
   // Implementation backing the as() method.  Needs to be a struct to allow partial
   // specialization.  Has a method apply() which does the work.
 
   friend class Orphanage;  // to speed up newOrphanCopy(DynamicValue::Reader)
 };
 
 class DynamicValue::Builder {
 public:
   typedef DynamicValue Builds;
 
   inline Builder(decltype(nullptr) n = nullptr);  // UNKNOWN
   inline Builder(Void value);
   inline Builder(bool value);
   inline Builder(char value);
   inline Builder(signed char value);
   inline Builder(short value);
   inline Builder(int value);
   inline Builder(long value);
   inline Builder(long long value);
   inline Builder(unsigned char value);
   inline Builder(unsigned short value);
   inline Builder(unsigned int value);
   inline Builder(unsigned long value);
   inline Builder(unsigned long long value);
   inline Builder(float value);
   inline Builder(double value);
   inline Builder(Text::Builder value);
   inline Builder(Data::Builder value);
   inline Builder(DynamicList::Builder value);
   inline Builder(DynamicEnum value);
   inline Builder(DynamicStruct::Builder value);
   inline Builder(AnyPointer::Builder value);
   inline Builder(DynamicCapability::Client& value);
   inline Builder(DynamicCapability::Client&& value);
 
   template <typename T, typename = decltype(toDynamic(kj::instance<T>()))>
   inline Builder(T value): Builder(toDynamic(value)) {}
 
   Builder(Builder& other);
   Builder(Builder&& other) noexcept;
   ~Builder() noexcept(false);
   Builder& operator=(Builder& other);
   Builder& operator=(Builder&& other);
   // Unfortunately, we cannot use the implicit definitions of these since DynamicCapability is not
   // trivially copyable.
 
   template <typename T>
   inline BuilderFor<T> as() { return AsImpl<T>::apply(*this); }
   // See DynamicValue::Reader::as().
 
   inline Type getType() { return type; }
   // Get the type of this value.
 
   Reader asReader() const;
 
 private:
   Type type;
 
   union {
     Void voidValue;
     bool boolValue;
     int64_t intValue;
     uint64_t uintValue;
     double floatValue;
     Text::Builder textValue;
     Data::Builder dataValue;
     DynamicList::Builder listValue;
     DynamicEnum enumValue;
     DynamicStruct::Builder structValue;
     AnyPointer::Builder anyPointerValue;
 
     mutable DynamicCapability::Client capabilityValue;
     // Declared mutable because `Client`s normally cannot be const.
   };
 
   template <typename T, Kind kind = kind<T>()> struct AsImpl;
   // Implementation backing the as() method.  Needs to be a struct to allow partial
   // specialization.  Has a method apply() which does the work.
 
   friend class Orphan<DynamicValue>;
 };
 
 class DynamicValue::Pipeline {
 public:
   typedef DynamicValue Pipelines;
 
   inline Pipeline(decltype(nullptr) n = nullptr);
   inline Pipeline(DynamicStruct::Pipeline&& value);
   inline Pipeline(DynamicCapability::Client&& value);
 
   Pipeline(Pipeline&& other) noexcept;
   Pipeline& operator=(Pipeline&& other);
   ~Pipeline() noexcept(false);
 
   template <typename T>
   inline PipelineFor<T> releaseAs() { return AsImpl<T>::apply(*this); }
 
   inline Type getType() { return type; }
   // Get the type of this value.
 
 private:
   Type type;
   union {
     DynamicStruct::Pipeline structValue;
     DynamicCapability::Client capabilityValue;
   };
 
   template <typename T, Kind kind = kind<T>()> struct AsImpl;
   // Implementation backing the releaseAs() method.  Needs to be a struct to allow partial
   // specialization.  Has a method apply() which does the work.
 };
 
 kj::StringTree KJ_STRINGIFY(const DynamicValue::Reader& value);
 kj::StringTree KJ_STRINGIFY(const DynamicValue::Builder& value);
 kj::StringTree KJ_STRINGIFY(DynamicEnum value);
 kj::StringTree KJ_STRINGIFY(const DynamicStruct::Reader& value);
 kj::StringTree KJ_STRINGIFY(const DynamicStruct::Builder& value);
 kj::StringTree KJ_STRINGIFY(const DynamicList::Reader& value);
 kj::StringTree KJ_STRINGIFY(const DynamicList::Builder& value);
 
 // -------------------------------------------------------------------
 // Orphan <-> Dynamic glue
 
 template <>
 class Orphan<DynamicStruct> {
 public:
   Orphan() = default;
   KJ_DISALLOW_COPY(Orphan);
   Orphan(Orphan&&) = default;
   Orphan& operator=(Orphan&&) = default;
 
   template <typename T, typename = kj::EnableIf<kind<T>() == Kind::STRUCT>>
   inline Orphan(Orphan<T>&& other): schema(Schema::from<T>()), builder(kj::mv(other.builder)) {}
 
   DynamicStruct::Builder get();
   DynamicStruct::Reader getReader() const;
 
   template <typename T>
   Orphan<T> releaseAs();
   // Like DynamicStruct::Builder::as(), but coerces the Orphan type.  Since Orphans are move-only,
   // the original Orphan<DynamicStruct> is no longer valid after this call; ownership is
   // transferred to the returned Orphan<T>.
 
   inline bool operator==(decltype(nullptr)) const { return builder == nullptr; }
   inline bool operator!=(decltype(nullptr)) const { return builder != nullptr; }
 
 private:
   StructSchema schema;
   _::OrphanBuilder builder;
 
   inline Orphan(StructSchema schema, _::OrphanBuilder&& builder)
       : schema(schema), builder(kj::mv(builder)) {}
 
   template <typename, Kind>
   friend struct _::PointerHelpers;
   friend struct DynamicList;
   friend class Orphanage;
   friend class Orphan<DynamicValue>;
   friend class Orphan<AnyPointer>;
   friend class MessageBuilder;
 };
 
 template <>
 class Orphan<DynamicList> {
 public:
   Orphan() = default;
   KJ_DISALLOW_COPY(Orphan);
   Orphan(Orphan&&) = default;
   Orphan& operator=(Orphan&&) = default;
 
   template <typename T, typename = kj::EnableIf<kind<T>() == Kind::LIST>>
   inline Orphan(Orphan<T>&& other): schema(Schema::from<T>()), builder(kj::mv(other.builder)) {}
 
   DynamicList::Builder get();
   DynamicList::Reader getReader() const;
 
   template <typename T>
   Orphan<T> releaseAs();
   // Like DynamicList::Builder::as(), but coerces the Orphan type.  Since Orphans are move-only,
   // the original Orphan<DynamicStruct> is no longer valid after this call; ownership is
   // transferred to the returned Orphan<T>.
 
   // TODO(someday): Support truncate().
 
   inline bool operator==(decltype(nullptr)) const { return builder == nullptr; }
   inline bool operator!=(decltype(nullptr)) const { return builder != nullptr; }
 
 private:
   ListSchema schema;
   _::OrphanBuilder builder;
 
   inline Orphan(ListSchema schema, _::OrphanBuilder&& builder)
       : schema(schema), builder(kj::mv(builder)) {}
 
   template <typename, Kind>
   friend struct _::PointerHelpers;
   friend struct DynamicList;
   friend class Orphanage;
   friend class Orphan<DynamicValue>;
   friend class Orphan<AnyPointer>;
 };
 
 template <>
 class Orphan<DynamicCapability> {
 public:
   Orphan() = default;
   KJ_DISALLOW_COPY(Orphan);
   Orphan(Orphan&&) = default;
   Orphan& operator=(Orphan&&) = default;
 
   template <typename T, typename = kj::EnableIf<kind<T>() == Kind::INTERFACE>>
   inline Orphan(Orphan<T>&& other): schema(Schema::from<T>()), builder(kj::mv(other.builder)) {}
 
   DynamicCapability::Client get();
   DynamicCapability::Client getReader() const;
 
   template <typename T>
   Orphan<T> releaseAs();
   // Like DynamicCapability::Client::as(), but coerces the Orphan type.  Since Orphans are move-only,
   // the original Orphan<DynamicCapability> is no longer valid after this call; ownership is
   // transferred to the returned Orphan<T>.
 
   inline bool operator==(decltype(nullptr)) const { return builder == nullptr; }
   inline bool operator!=(decltype(nullptr)) const { return builder != nullptr; }
 
 private:
   InterfaceSchema schema;
   _::OrphanBuilder builder;
 
   inline Orphan(InterfaceSchema schema, _::OrphanBuilder&& builder)
       : schema(schema), builder(kj::mv(builder)) {}
 
   template <typename, Kind>
   friend struct _::PointerHelpers;
   friend struct DynamicList;
   friend class Orphanage;
   friend class Orphan<DynamicValue>;
   friend class Orphan<AnyPointer>;
 };
 
 template <>
 class Orphan<DynamicValue> {
 public:
   inline Orphan(decltype(nullptr) n = nullptr): type(DynamicValue::UNKNOWN) {}
   inline Orphan(Void value);
   inline Orphan(bool value);
   inline Orphan(char value);
   inline Orphan(signed char value);
   inline Orphan(short value);
   inline Orphan(int value);
   inline Orphan(long value);
   inline Orphan(long long value);
   inline Orphan(unsigned char value);
   inline Orphan(unsigned short value);
   inline Orphan(unsigned int value);
   inline Orphan(unsigned long value);
   inline Orphan(unsigned long long value);
   inline Orphan(float value);
   inline Orphan(double value);
   inline Orphan(DynamicEnum value);
   Orphan(Orphan&&) = default;
   template <typename T>
   Orphan(Orphan<T>&&);
   Orphan(Orphan<AnyPointer>&&);
   Orphan(void*) = delete;  // So Orphan(bool) doesn't accept pointers.
   KJ_DISALLOW_COPY(Orphan);
 
   Orphan& operator=(Orphan&&) = default;
 
   inline DynamicValue::Type getType() { return type; }
 
   DynamicValue::Builder get();
   DynamicValue::Reader getReader() const;
 
   template <typename T>
   Orphan<T> releaseAs();
   // Like DynamicValue::Builder::as(), but coerces the Orphan type.  Since Orphans are move-only,
   // the original Orphan<DynamicStruct> is no longer valid after this call; ownership is
   // transferred to the returned Orphan<T>.
 
 private:
   DynamicValue::Type type;
   union {
     Void voidValue;
     bool boolValue;
     int64_t intValue;
     uint64_t uintValue;
     double floatValue;
     DynamicEnum enumValue;
     StructSchema structSchema;
     ListSchema listSchema;
     InterfaceSchema interfaceSchema;
   };
 
   _::OrphanBuilder builder;
   // Only used if `type` is a pointer type.
 
   Orphan(DynamicValue::Builder value, _::OrphanBuilder&& builder);
   Orphan(DynamicValue::Type type, _::OrphanBuilder&& builder)
       : type(type), builder(kj::mv(builder)) {}
   Orphan(StructSchema structSchema, _::OrphanBuilder&& builder)
       : type(DynamicValue::STRUCT), structSchema(structSchema), builder(kj::mv(builder)) {}
   Orphan(ListSchema listSchema, _::OrphanBuilder&& builder)
       : type(DynamicValue::LIST), listSchema(listSchema), builder(kj::mv(builder)) {}
 
   template <typename, Kind>
   friend struct _::PointerHelpers;
   friend struct DynamicStruct;
   friend struct DynamicList;
   friend struct AnyPointer;
   friend class Orphanage;
 };
 
 template <typename T>
 inline Orphan<DynamicValue>::Orphan(Orphan<T>&& other)
     : Orphan(other.get(), kj::mv(other.builder)) {}
 
 inline Orphan<DynamicValue>::Orphan(Orphan<AnyPointer>&& other)
     : type(DynamicValue::ANY_POINTER), builder(kj::mv(other.builder)) {}
 
 template <typename T>
 Orphan<T> Orphan<DynamicStruct>::releaseAs() {
   get().as<T>();  // type check
   return Orphan<T>(kj::mv(builder));
 }
 
 template <typename T>
 Orphan<T> Orphan<DynamicList>::releaseAs() {
   get().as<T>();  // type check
   return Orphan<T>(kj::mv(builder));
 }
 
 template <typename T>
 Orphan<T> Orphan<DynamicCapability>::releaseAs() {
   get().as<T>();  // type check
   return Orphan<T>(kj::mv(builder));
 }
 
 template <typename T>
 Orphan<T> Orphan<DynamicValue>::releaseAs() {
   get().as<T>();  // type check
   type = DynamicValue::UNKNOWN;
   return Orphan<T>(kj::mv(builder));
 }
 
 template <>
 Orphan<AnyPointer> Orphan<DynamicValue>::releaseAs<AnyPointer>();
 template <>
 Orphan<DynamicStruct> Orphan<DynamicValue>::releaseAs<DynamicStruct>();
 template <>
 Orphan<DynamicList> Orphan<DynamicValue>::releaseAs<DynamicList>();
 template <>
 Orphan<DynamicCapability> Orphan<DynamicValue>::releaseAs<DynamicCapability>();
 
 template <>
 struct Orphanage::GetInnerBuilder<DynamicStruct, Kind::OTHER> {
   static inline _::StructBuilder apply(DynamicStruct::Builder& t) {
     return t.builder;
   }
 };
 
 template <>
 struct Orphanage::GetInnerBuilder<DynamicList, Kind::OTHER> {
   static inline _::ListBuilder apply(DynamicList::Builder& t) {
     return t.builder;
   }
 };
 
 template <>
 inline Orphan<DynamicStruct> Orphanage::newOrphanCopy<DynamicStruct::Reader>(
     DynamicStruct::Reader copyFrom) const {
   return Orphan<DynamicStruct>(
       copyFrom.getSchema(), _::OrphanBuilder::copy(arena, capTable, copyFrom.reader));
 }
 
 template <>
 inline Orphan<DynamicList> Orphanage::newOrphanCopy<DynamicList::Reader>(
     DynamicList::Reader copyFrom) const {
   return Orphan<DynamicList>(copyFrom.getSchema(),
       _::OrphanBuilder::copy(arena, capTable, copyFrom.reader));
 }
 
 template <>
 inline Orphan<DynamicCapability> Orphanage::newOrphanCopy<DynamicCapability::Client>(
     DynamicCapability::Client copyFrom) const {
   return Orphan<DynamicCapability>(
       copyFrom.getSchema(), _::OrphanBuilder::copy(arena, capTable, copyFrom.hook->addRef()));
 }
 
 template <>
 Orphan<DynamicValue> Orphanage::newOrphanCopy<DynamicValue::Reader>(
     DynamicValue::Reader copyFrom) const;
 
 namespace _ {  // private
 
 template <>
 struct PointerHelpers<DynamicStruct, Kind::OTHER> {
   // getDynamic() is used when an AnyPointer's get() accessor is passed arguments, because for
   // non-dynamic types PointerHelpers::get() takes a default value as the third argument, and we
   // don't want people to accidentally be able to provide their own default value.
   static DynamicStruct::Reader getDynamic(PointerReader reader, StructSchema schema);
   static DynamicStruct::Builder getDynamic(PointerBuilder builder, StructSchema schema);
   static void set(PointerBuilder builder, const DynamicStruct::Reader& value);
   static DynamicStruct::Builder init(PointerBuilder builder, StructSchema schema);
   static inline void adopt(PointerBuilder builder, Orphan<DynamicStruct>&& value) {
     builder.adopt(kj::mv(value.builder));
   }
   static inline Orphan<DynamicStruct> disown(PointerBuilder builder, StructSchema schema) {
     return Orphan<DynamicStruct>(schema, builder.disown());
   }
 };
 
 template <>
 struct PointerHelpers<DynamicList, Kind::OTHER> {
   // getDynamic() is used when an AnyPointer's get() accessor is passed arguments, because for
   // non-dynamic types PointerHelpers::get() takes a default value as the third argument, and we
   // don't want people to accidentally be able to provide their own default value.
   static DynamicList::Reader getDynamic(PointerReader reader, ListSchema schema);
   static DynamicList::Builder getDynamic(PointerBuilder builder, ListSchema schema);
   static void set(PointerBuilder builder, const DynamicList::Reader& value);
   static DynamicList::Builder init(PointerBuilder builder, ListSchema schema, uint size);
   static inline void adopt(PointerBuilder builder, Orphan<DynamicList>&& value) {
     builder.adopt(kj::mv(value.builder));
   }
   static inline Orphan<DynamicList> disown(PointerBuilder builder, ListSchema schema) {
     return Orphan<DynamicList>(schema, builder.disown());
   }
 };
 
 template <>
 struct PointerHelpers<DynamicCapability, Kind::OTHER> {
   // getDynamic() is used when an AnyPointer's get() accessor is passed arguments, because for
   // non-dynamic types PointerHelpers::get() takes a default value as the third argument, and we
   // don't want people to accidentally be able to provide their own default value.
   static DynamicCapability::Client getDynamic(PointerReader reader, InterfaceSchema schema);
   static DynamicCapability::Client getDynamic(PointerBuilder builder, InterfaceSchema schema);
   static void set(PointerBuilder builder, DynamicCapability::Client& value);
   static void set(PointerBuilder builder, DynamicCapability::Client&& value);
   static inline void adopt(PointerBuilder builder, Orphan<DynamicCapability>&& value) {
     builder.adopt(kj::mv(value.builder));
   }
   static inline Orphan<DynamicCapability> disown(PointerBuilder builder, InterfaceSchema schema) {
     return Orphan<DynamicCapability>(schema, builder.disown());
   }
 };
 
 }  // namespace _ (private)
 
 template <typename T>
 inline ReaderFor<T> AnyPointer::Reader::getAs(StructSchema schema) const {
   return _::PointerHelpers<T>::getDynamic(reader, schema);
 }
 template <typename T>
 inline ReaderFor<T> AnyPointer::Reader::getAs(ListSchema schema) const {
   return _::PointerHelpers<T>::getDynamic(reader, schema);
 }
 template <typename T>
 inline ReaderFor<T> AnyPointer::Reader::getAs(InterfaceSchema schema) const {
   return _::PointerHelpers<T>::getDynamic(reader, schema);
 }
 template <typename T>
 inline BuilderFor<T> AnyPointer::Builder::getAs(StructSchema schema) {
   return _::PointerHelpers<T>::getDynamic(builder, schema);
 }
 template <typename T>
 inline BuilderFor<T> AnyPointer::Builder::getAs(ListSchema schema) {
   return _::PointerHelpers<T>::getDynamic(builder, schema);
 }
 template <typename T>
 inline BuilderFor<T> AnyPointer::Builder::getAs(InterfaceSchema schema) {
   return _::PointerHelpers<T>::getDynamic(builder, schema);
 }
 template <typename T>
 inline BuilderFor<T> AnyPointer::Builder::initAs(StructSchema schema) {
   return _::PointerHelpers<T>::init(builder, schema);
 }
 template <typename T>
 inline BuilderFor<T> AnyPointer::Builder::initAs(ListSchema schema, uint elementCount) {
   return _::PointerHelpers<T>::init(builder, schema, elementCount);
 }
 template <>
 inline void AnyPointer::Builder::setAs<DynamicStruct>(DynamicStruct::Reader value) {
   return _::PointerHelpers<DynamicStruct>::set(builder, value);
 }
 template <>
 inline void AnyPointer::Builder::setAs<DynamicList>(DynamicList::Reader value) {
   return _::PointerHelpers<DynamicList>::set(builder, value);
 }
 template <>
 inline void AnyPointer::Builder::setAs<DynamicCapability>(DynamicCapability::Client value) {
   return _::PointerHelpers<DynamicCapability>::set(builder, kj::mv(value));
 }
 template <>
 void AnyPointer::Builder::adopt<DynamicValue>(Orphan<DynamicValue>&& orphan);
 template <typename T>
 inline Orphan<T> AnyPointer::Builder::disownAs(StructSchema schema) {
   return _::PointerHelpers<T>::disown(builder, schema);
 }
 template <typename T>
 inline Orphan<T> AnyPointer::Builder::disownAs(ListSchema schema) {
   return _::PointerHelpers<T>::disown(builder, schema);
 }
 template <typename T>
 inline Orphan<T> AnyPointer::Builder::disownAs(InterfaceSchema schema) {
   return _::PointerHelpers<T>::disown(builder, schema);
 }
 
 // We have to declare the methods below inline because Clang and GCC disagree about how to mangle
 // their symbol names.
 template <>
 inline DynamicStruct::Builder Orphan<AnyPointer>::getAs<DynamicStruct>(StructSchema schema) {
   return DynamicStruct::Builder(schema, builder);
 }
 template <>
 inline DynamicStruct::Reader Orphan<AnyPointer>::getAsReader<DynamicStruct>(
     StructSchema schema) const {
   return DynamicStruct::Reader(schema, builder);
 }
 template <>
 inline Orphan<DynamicStruct> Orphan<AnyPointer>::releaseAs<DynamicStruct>(StructSchema schema) {
   return Orphan<DynamicStruct>(schema, kj::mv(builder));
 }
 template <>
 inline DynamicList::Builder Orphan<AnyPointer>::getAs<DynamicList>(ListSchema schema) {
   return DynamicList::Builder(schema, builder);
 }
 template <>
 inline DynamicList::Reader Orphan<AnyPointer>::getAsReader<DynamicList>(ListSchema schema) const {
   return DynamicList::Reader(schema, builder);
 }
 template <>
 inline Orphan<DynamicList> Orphan<AnyPointer>::releaseAs<DynamicList>(ListSchema schema) {
   return Orphan<DynamicList>(schema, kj::mv(builder));
 }
 template <>
 inline DynamicCapability::Client Orphan<AnyPointer>::getAs<DynamicCapability>(
     InterfaceSchema schema) {
   return DynamicCapability::Client(schema, builder.asCapability());
 }
 template <>
 inline DynamicCapability::Client Orphan<AnyPointer>::getAsReader<DynamicCapability>(
     InterfaceSchema schema) const {
   return DynamicCapability::Client(schema, builder.asCapability());
 }
 template <>
 inline Orphan<DynamicCapability> Orphan<AnyPointer>::releaseAs<DynamicCapability>(
     InterfaceSchema schema) {
   return Orphan<DynamicCapability>(schema, kj::mv(builder));
 }
 
 // =======================================================================================
 // Inline implementation details.
 
 template <typename T>
 struct ToDynamic_<T, Kind::STRUCT> {
   static inline DynamicStruct::Reader apply(const typename T::Reader& value) {
     return DynamicStruct::Reader(Schema::from<T>(), value._reader);
   }
   static inline DynamicStruct::Builder apply(typename T::Builder& value) {
     return DynamicStruct::Builder(Schema::from<T>(), value._builder);
   }
 };
 
 template <typename T>
 struct ToDynamic_<T, Kind::LIST> {
   static inline DynamicList::Reader apply(const typename T::Reader& value) {
     return DynamicList::Reader(Schema::from<T>(), value.reader);
   }
   static inline DynamicList::Builder apply(typename T::Builder& value) {
     return DynamicList::Builder(Schema::from<T>(), value.builder);
   }
 };
 
 template <typename T>
 struct ToDynamic_<T, Kind::INTERFACE> {
   static inline DynamicCapability::Client apply(typename T::Client value) {
     return DynamicCapability::Client(kj::mv(value));
   }
   static inline DynamicCapability::Client apply(typename T::Client&& value) {
     return DynamicCapability::Client(kj::mv(value));
   }
 };
 
 template <typename T>
 ReaderFor<DynamicTypeFor<FromReader<T>>> toDynamic(T&& value) {
   return ToDynamic_<FromReader<T>>::apply(value);
 }
 template <typename T>
 BuilderFor<DynamicTypeFor<FromBuilder<T>>> toDynamic(T&& value) {
   return ToDynamic_<FromBuilder<T>>::apply(value);
 }
 template <typename T>
 DynamicTypeFor<TypeIfEnum<T>> toDynamic(T&& value) {
   return DynamicEnum(Schema::from<kj::Decay<T>>(), static_cast<uint16_t>(value));
 }
 template <typename T>
 typename DynamicTypeFor<FromServer<T>>::Client toDynamic(kj::Own<T>&& value) {
   return typename FromServer<T>::Client(kj::mv(value));
 }
 
 inline DynamicValue::Reader::Reader(std::nullptr_t n): type(UNKNOWN) {}
 inline DynamicValue::Builder::Builder(std::nullptr_t n): type(UNKNOWN) {}
 
 #define CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(cppType, typeTag, fieldName) \
 inline DynamicValue::Reader::Reader(cppType value) \
     : type(typeTag), fieldName##Value(value) {} \
 inline DynamicValue::Builder::Builder(cppType value) \
     : type(typeTag), fieldName##Value(value) {} \
 inline Orphan<DynamicValue>::Orphan(cppType value) \
     : type(DynamicValue::typeTag), fieldName##Value(value) {}
 
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(Void, VOID, void);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(bool, BOOL, bool);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(char, INT, int);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(signed char, INT, int);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(short, INT, int);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(int, INT, int);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(long, INT, int);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(long long, INT, int);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(unsigned char, UINT, uint);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(unsigned short, UINT, uint);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(unsigned int, UINT, uint);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(unsigned long, UINT, uint);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(unsigned long long, UINT, uint);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(float, FLOAT, float);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(double, FLOAT, float);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(DynamicEnum, ENUM, enum);
 #undef CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR
 
 #define CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(cppType, typeTag, fieldName) \
 inline DynamicValue::Reader::Reader(const cppType::Reader& value) \
     : type(typeTag), fieldName##Value(value) {} \
 inline DynamicValue::Builder::Builder(cppType::Builder value) \
     : type(typeTag), fieldName##Value(value) {}
 
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(Text, TEXT, text);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(Data, DATA, data);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(DynamicList, LIST, list);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(DynamicStruct, STRUCT, struct);
 CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR(AnyPointer, ANY_POINTER, anyPointer);
 
 #undef CAPNP_DECLARE_DYNAMIC_VALUE_CONSTRUCTOR
 
 inline DynamicValue::Reader::Reader(DynamicCapability::Client& value)
     : type(CAPABILITY), capabilityValue(value) {}
 inline DynamicValue::Reader::Reader(DynamicCapability::Client&& value)
     : type(CAPABILITY), capabilityValue(kj::mv(value)) {}
 template <typename T, typename>
 inline DynamicValue::Reader::Reader(kj::Own<T>&& value)
     : type(CAPABILITY), capabilityValue(kj::mv(value)) {}
 inline DynamicValue::Builder::Builder(DynamicCapability::Client& value)
     : type(CAPABILITY), capabilityValue(value) {}
 inline DynamicValue::Builder::Builder(DynamicCapability::Client&& value)
     : type(CAPABILITY), capabilityValue(kj::mv(value)) {}
 
 inline DynamicValue::Reader::Reader(const char* value): Reader(Text::Reader(value)) {}
 
 #define CAPNP_DECLARE_TYPE(discrim, typeName) \
 template <> \
 struct DynamicValue::Reader::AsImpl<typeName> { \
   static ReaderFor<typeName> apply(const Reader& reader); \
 }; \
 template <> \
 struct DynamicValue::Builder::AsImpl<typeName> { \
   static BuilderFor<typeName> apply(Builder& builder); \
 };
 
 //CAPNP_DECLARE_TYPE(VOID, Void)
 CAPNP_DECLARE_TYPE(BOOL, bool)
 CAPNP_DECLARE_TYPE(INT8, int8_t)
 CAPNP_DECLARE_TYPE(INT16, int16_t)
 CAPNP_DECLARE_TYPE(INT32, int32_t)
 CAPNP_DECLARE_TYPE(INT64, int64_t)
 CAPNP_DECLARE_TYPE(UINT8, uint8_t)
 CAPNP_DECLARE_TYPE(UINT16, uint16_t)
 CAPNP_DECLARE_TYPE(UINT32, uint32_t)
 CAPNP_DECLARE_TYPE(UINT64, uint64_t)
 CAPNP_DECLARE_TYPE(FLOAT32, float)
 CAPNP_DECLARE_TYPE(FLOAT64, double)
 
 CAPNP_DECLARE_TYPE(TEXT, Text)
 CAPNP_DECLARE_TYPE(DATA, Data)
 CAPNP_DECLARE_TYPE(LIST, DynamicList)
 CAPNP_DECLARE_TYPE(STRUCT, DynamicStruct)
 CAPNP_DECLARE_TYPE(INTERFACE, DynamicCapability)
 CAPNP_DECLARE_TYPE(ENUM, DynamicEnum)
 CAPNP_DECLARE_TYPE(ANY_POINTER, AnyPointer)
 #undef CAPNP_DECLARE_TYPE
 
 // CAPNP_DECLARE_TYPE(Void) causes gcc 4.7 to segfault.  If I do it manually and remove the
 // ReaderFor<> and BuilderFor<> wrappers, it works.
 template <>
 struct DynamicValue::Reader::AsImpl<Void> {
   static Void apply(const Reader& reader);
 };
 template <>
 struct DynamicValue::Builder::AsImpl<Void> {
   static Void apply(Builder& builder);
 };
 
 template <typename T>
 struct DynamicValue::Reader::AsImpl<T, Kind::ENUM> {
   static T apply(const Reader& reader) {
     return reader.as<DynamicEnum>().as<T>();
   }
 };
 template <typename T>
 struct DynamicValue::Builder::AsImpl<T, Kind::ENUM> {
   static T apply(Builder& builder) {
     return builder.as<DynamicEnum>().as<T>();
   }
 };
 
 template <typename T>
 struct DynamicValue::Reader::AsImpl<T, Kind::STRUCT> {
   static typename T::Reader apply(const Reader& reader) {
     return reader.as<DynamicStruct>().as<T>();
   }
 };
 template <typename T>
 struct DynamicValue::Builder::AsImpl<T, Kind::STRUCT> {
   static typename T::Builder apply(Builder& builder) {
     return builder.as<DynamicStruct>().as<T>();
   }
 };
 
 template <typename T>
 struct DynamicValue::Reader::AsImpl<T, Kind::LIST> {
   static typename T::Reader apply(const Reader& reader) {
     return reader.as<DynamicList>().as<T>();
   }
 };
 template <typename T>
 struct DynamicValue::Builder::AsImpl<T, Kind::LIST> {
   static typename T::Builder apply(Builder& builder) {
     return builder.as<DynamicList>().as<T>();
   }
 };
 
 template <typename T>
 struct DynamicValue::Reader::AsImpl<T, Kind::INTERFACE> {
   static typename T::Client apply(const Reader& reader) {
     return reader.as<DynamicCapability>().as<T>();
   }
 };
 template <typename T>
 struct DynamicValue::Builder::AsImpl<T, Kind::INTERFACE> {
   static typename T::Client apply(Builder& builder) {
     return builder.as<DynamicCapability>().as<T>();
   }
 };
 
 template <>
 struct DynamicValue::Reader::AsImpl<DynamicValue> {
   static DynamicValue::Reader apply(const Reader& reader) {
     return reader;
   }
 };
 template <>
 struct DynamicValue::Builder::AsImpl<DynamicValue> {
   static DynamicValue::Builder apply(Builder& builder) {
     return builder;
   }
 };
 
 inline DynamicValue::Pipeline::Pipeline(std::nullptr_t n): type(UNKNOWN) {}
 inline DynamicValue::Pipeline::Pipeline(DynamicStruct::Pipeline&& value)
     : type(STRUCT), structValue(kj::mv(value)) {}
 inline DynamicValue::Pipeline::Pipeline(DynamicCapability::Client&& value)
     : type(CAPABILITY), capabilityValue(kj::mv(value)) {}
 
 template <typename T>
 struct DynamicValue::Pipeline::AsImpl<T, Kind::STRUCT> {
   static typename T::Pipeline apply(Pipeline& pipeline) {
     return pipeline.releaseAs<DynamicStruct>().releaseAs<T>();
   }
 };
 template <typename T>
 struct DynamicValue::Pipeline::AsImpl<T, Kind::INTERFACE> {
   static typename T::Client apply(Pipeline& pipeline) {
     return pipeline.releaseAs<DynamicCapability>().releaseAs<T>();
   }
 };
 template <>
 struct DynamicValue::Pipeline::AsImpl<DynamicStruct, Kind::OTHER> {
   static PipelineFor<DynamicStruct> apply(Pipeline& pipeline);
 };
 template <>
 struct DynamicValue::Pipeline::AsImpl<DynamicCapability, Kind::OTHER> {
   static PipelineFor<DynamicCapability> apply(Pipeline& pipeline);
 };
 
 // -------------------------------------------------------------------
 
 template <typename T>
 typename T::Reader DynamicStruct::Reader::as() const {
   static_assert(kind<T>() == Kind::STRUCT,
                 "DynamicStruct::Reader::as<T>() can only convert to struct types.");
   schema.requireUsableAs<T>();
   return typename T::Reader(reader);
 }
 
 template <typename T>
 typename T::Builder DynamicStruct::Builder::as() {
   static_assert(kind<T>() == Kind::STRUCT,
                 "DynamicStruct::Builder::as<T>() can only convert to struct types.");
   schema.requireUsableAs<T>();
   return typename T::Builder(builder);
 }
 
 template <>
 inline DynamicStruct::Reader DynamicStruct::Reader::as<DynamicStruct>() const {
   return *this;
 }
 template <>
 inline DynamicStruct::Builder DynamicStruct::Builder::as<DynamicStruct>() {
   return *this;
 }
 
 inline DynamicStruct::Reader DynamicStruct::Builder::asReader() const {
   return DynamicStruct::Reader(schema, builder.asReader());
 }
 
 template <>
 inline AnyStruct::Reader DynamicStruct::Reader::as<AnyStruct>() const {
   return AnyStruct::Reader(reader);
 }
 
 template <>
 inline AnyStruct::Builder DynamicStruct::Builder::as<AnyStruct>() {
   return AnyStruct::Builder(builder);
 }
 
 template <>
 inline DynamicStruct::Reader AnyStruct::Reader::as<DynamicStruct>(StructSchema schema) const {
   return DynamicStruct::Reader(schema, _reader);
 }
 
 template <>
 inline DynamicStruct::Builder AnyStruct::Builder::as<DynamicStruct>(StructSchema schema) {
   return DynamicStruct::Builder(schema, _builder);
 }
 
 template <typename T>
 typename T::Pipeline DynamicStruct::Pipeline::releaseAs() {
   static_assert(kind<T>() == Kind::STRUCT,
                 "DynamicStruct::Pipeline::releaseAs<T>() can only convert to struct types.");
   schema.requireUsableAs<T>();
   return typename T::Pipeline(kj::mv(typeless));
 }
 
 // -------------------------------------------------------------------
 
 template <typename T>
 typename T::Reader DynamicList::Reader::as() const {
   static_assert(kind<T>() == Kind::LIST,
                 "DynamicStruct::Reader::as<T>() can only convert to list types.");
   schema.requireUsableAs<T>();
   return typename T::Reader(reader);
 }
 template <typename T>
 typename T::Builder DynamicList::Builder::as() {
   static_assert(kind<T>() == Kind::LIST,
                 "DynamicStruct::Builder::as<T>() can only convert to list types.");
   schema.requireUsableAs<T>();
   return typename T::Builder(builder);
 }
 
 template <>
 inline DynamicList::Reader DynamicList::Reader::as<DynamicList>() const {
   return *this;
 }
 template <>
 inline DynamicList::Builder DynamicList::Builder::as<DynamicList>() {
   return *this;
 }
 
 template <>
 inline AnyList::Reader DynamicList::Reader::as<AnyList>() const {
   return AnyList::Reader(reader);
 }
 
 template <>
 inline AnyList::Builder DynamicList::Builder::as<AnyList>() {
   return AnyList::Builder(builder);
 }
 
 // -------------------------------------------------------------------
 
 template <typename T, typename>
 inline DynamicCapability::Client::Client(T&& client)
     : Capability::Client(kj::mv(client)), schema(Schema::from<FromClient<T>>()) {}
 
 template <typename T, typename>
 inline DynamicCapability::Client::Client(kj::Own<T>&& server)
     : Client(server->getSchema(), kj::mv(server)) {}
 template <typename T>
 inline DynamicCapability::Client::Client(InterfaceSchema schema, kj::Own<T>&& server)
     : Capability::Client(kj::mv(server)), schema(schema) {}
 
 template <typename T, typename>
 typename T::Client DynamicCapability::Client::as() {
   static_assert(kind<T>() == Kind::INTERFACE,
                 "DynamicCapability::Client::as<T>() can only convert to interface types.");
   schema.requireUsableAs<T>();
   return typename T::Client(hook->addRef());
 }
 
 template <typename T, typename>
 typename T::Client DynamicCapability::Client::releaseAs() {
   static_assert(kind<T>() == Kind::INTERFACE,
                 "DynamicCapability::Client::as<T>() can only convert to interface types.");
   schema.requireUsableAs<T>();
   return typename T::Client(kj::mv(hook));
 }
 
 inline CallContext<DynamicStruct, DynamicStruct>::CallContext(
     CallContextHook& hook, StructSchema paramType, StructSchema resultType)
     : hook(&hook), paramType(paramType), resultType(resultType) {}
 inline DynamicStruct::Reader CallContext<DynamicStruct, DynamicStruct>::getParams() {
   return hook->getParams().getAs<DynamicStruct>(paramType);
 }
 inline void CallContext<DynamicStruct, DynamicStruct>::releaseParams() {
   hook->releaseParams();
 }
 inline DynamicStruct::Builder CallContext<DynamicStruct, DynamicStruct>::getResults(
     kj::Maybe<MessageSize> sizeHint) {
   return hook->getResults(sizeHint).getAs<DynamicStruct>(resultType);
 }
 inline DynamicStruct::Builder CallContext<DynamicStruct, DynamicStruct>::initResults(
     kj::Maybe<MessageSize> sizeHint) {
   return hook->getResults(sizeHint).initAs<DynamicStruct>(resultType);
 }
 inline void CallContext<DynamicStruct, DynamicStruct>::setResults(DynamicStruct::Reader value) {
   hook->getResults(value.totalSize()).setAs<DynamicStruct>(value);
 }
 inline void CallContext<DynamicStruct, DynamicStruct>::adoptResults(Orphan<DynamicStruct>&& value) {
   hook->getResults(MessageSize { 0, 0 }).adopt(kj::mv(value));
 }
 inline Orphanage CallContext<DynamicStruct, DynamicStruct>::getResultsOrphanage(
     kj::Maybe<MessageSize> sizeHint) {
   return Orphanage::getForMessageContaining(hook->getResults(sizeHint));
 }
 template <typename SubParams>
 inline kj::Promise<void> CallContext<DynamicStruct, DynamicStruct>::tailCall(
     Request<SubParams, DynamicStruct>&& tailRequest) {
   return hook->tailCall(kj::mv(tailRequest.hook));
 }
 inline void CallContext<DynamicStruct, DynamicStruct>::allowCancellation() {
   hook->allowCancellation();
 }
 
 template <>
 inline DynamicCapability::Client Capability::Client::castAs<DynamicCapability>(
     InterfaceSchema schema) {
   return DynamicCapability::Client(schema, hook->addRef());
 }
 
 // -------------------------------------------------------------------
 
 template <typename T>
 ReaderFor<T> ConstSchema::as() const {
   return DynamicValue::Reader(*this).as<T>();
 }
 
 }  // namespace capnp
 
 CAPNP_END_HEADER