/usr/include/capnp/orphan.h is in libcapnp-dev 0.4.0-1ubuntu2.
This file is owned by root:root, with mode 0o644.
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// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this
// list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef CAPNP_ORPHAN_H_
#define CAPNP_ORPHAN_H_
#include "layout.h"
namespace capnp {
class StructSchema;
class ListSchema;
struct DynamicStruct;
struct DynamicList;
template <typename T>
class Orphan {
// Represents an object which is allocated within some message builder but has no pointers
// pointing at it. An Orphan can later be "adopted" by some other object as one of that object's
// fields, without having to copy the orphan. For a field `foo` of pointer type, the generated
// code will define builder methods `void adoptFoo(Orphan<T>)` and `Orphan<T> disownFoo()`.
// Orphans can also be created independently of any parent using an Orphanage.
//
// `Orphan<T>` can be moved but not copied, like `Own<T>`, so that it is impossible for one
// orphan to be adopted multiple times. If an orphan is destroyed without being adopted, its
// contents are zero'd out (and possibly reused, if we ever implement the ability to reuse space
// in a message arena).
public:
Orphan() = default;
KJ_DISALLOW_COPY(Orphan);
Orphan(Orphan&&) = default;
Orphan& operator=(Orphan&&) = default;
inline BuilderFor<T> get();
// Get the underlying builder. If the orphan is null, this will allocate and return a default
// object rather than crash. This is done for security -- otherwise, you might enable a DoS
// attack any time you disown a field and fail to check if it is null. In the case of structs,
// this means that the orphan is no longer null after get() returns. In the case of lists,
// no actual object is allocated since a simple empty ListBuilder can be returned.
inline ReaderFor<T> getReader() const;
inline bool operator==(decltype(nullptr)) const { return builder == nullptr; }
inline bool operator!=(decltype(nullptr)) const { return builder != nullptr; }
private:
_::OrphanBuilder builder;
inline Orphan(_::OrphanBuilder&& builder): builder(kj::mv(builder)) {}
template <typename, Kind>
friend struct _::PointerHelpers;
template <typename, Kind>
friend struct List;
template <typename U>
friend class Orphan;
friend class Orphanage;
friend class MessageBuilder;
};
class Orphanage: private kj::DisallowConstCopy {
// Use to directly allocate Orphan objects, without having a parent object allocate and then
// disown the object.
public:
inline Orphanage(): arena(nullptr) {}
template <typename BuilderType>
static Orphanage getForMessageContaining(BuilderType builder);
// Construct an Orphanage that allocates within the message containing the given Builder. This
// allows the constructed Orphans to be adopted by objects within said message.
//
// This constructor takes the builder rather than having the builder have a getOrphanage() method
// because this is an advanced feature and we don't want to pollute the builder APIs with it.
//
// Note that if you have a direct pointer to the `MessageBuilder`, you can simply call its
// `getOrphanage()` method.
template <typename RootType>
Orphan<RootType> newOrphan() const;
// Allocate a new orphaned struct.
template <typename RootType>
Orphan<RootType> newOrphan(uint size) const;
// Allocate a new orphaned list or blob.
Orphan<DynamicStruct> newOrphan(StructSchema schema) const;
// Dynamically create an orphan struct with the given schema. You must
// #include <capnp/dynamic.h> to use this.
Orphan<DynamicList> newOrphan(ListSchema schema, uint size) const;
// Dynamically create an orphan list with the given schema. You must #include <capnp/dynamic.h>
// to use this.
template <typename Reader>
Orphan<FromReader<Reader>> newOrphanCopy(const Reader& copyFrom) const;
template <typename Reader>
Orphan<FromReader<Reader>> newOrphanCopy(Reader& copyFrom) const;
// Allocate a new orphaned object (struct, list, or blob) and initialize it as a copy of the
// given object.
private:
_::BuilderArena* arena;
inline explicit Orphanage(_::BuilderArena* arena): arena(arena) {}
template <typename T, Kind = kind<T>()>
struct GetInnerBuilder;
template <typename T, Kind = kind<T>()>
struct GetInnerReader;
template <typename T>
struct NewOrphanListImpl;
friend class MessageBuilder;
};
// =======================================================================================
// Inline implementation details.
namespace _ { // private
template <typename T, Kind = kind<T>()>
struct OrphanGetImpl;
template <typename T>
struct OrphanGetImpl<T, Kind::STRUCT> {
static inline typename T::Builder apply(_::OrphanBuilder& builder) {
return typename T::Builder(builder.asStruct(_::structSize<T>()));
}
static inline typename T::Reader applyReader(const _::OrphanBuilder& builder) {
return typename T::Reader(builder.asStructReader(_::structSize<T>()));
}
};
template <typename T>
struct OrphanGetImpl<T, Kind::INTERFACE> {
static inline typename T::Client apply(_::OrphanBuilder& builder) {
return typename T::Client(builder.asCapability());
}
static inline typename T::Client applyReader(const _::OrphanBuilder& builder) {
return typename T::Client(builder.asCapability());
}
};
template <typename T, Kind k>
struct OrphanGetImpl<List<T, k>, Kind::LIST> {
static inline typename List<T>::Builder apply(_::OrphanBuilder& builder) {
return typename List<T>::Builder(builder.asList(_::ElementSizeForType<T>::value));
}
static inline typename List<T>::Reader applyReader(const _::OrphanBuilder& builder) {
return typename List<T>::Reader(builder.asListReader(_::ElementSizeForType<T>::value));
}
};
template <typename T>
struct OrphanGetImpl<List<T, Kind::STRUCT>, Kind::LIST> {
static inline typename List<T>::Builder apply(_::OrphanBuilder& builder) {
return typename List<T>::Builder(builder.asStructList(_::structSize<T>()));
}
static inline typename List<T>::Reader applyReader(const _::OrphanBuilder& builder) {
return typename List<T>::Reader(builder.asListReader(_::ElementSizeForType<T>::value));
}
};
template <>
struct OrphanGetImpl<Text, Kind::BLOB> {
static inline Text::Builder apply(_::OrphanBuilder& builder) {
return Text::Builder(builder.asText());
}
static inline Text::Reader applyReader(const _::OrphanBuilder& builder) {
return Text::Reader(builder.asTextReader());
}
};
template <>
struct OrphanGetImpl<Data, Kind::BLOB> {
static inline Data::Builder apply(_::OrphanBuilder& builder) {
return Data::Builder(builder.asData());
}
static inline Data::Reader applyReader(const _::OrphanBuilder& builder) {
return Data::Reader(builder.asDataReader());
}
};
} // namespace _ (private)
template <typename T>
inline BuilderFor<T> Orphan<T>::get() {
return _::OrphanGetImpl<T>::apply(builder);
}
template <typename T>
inline ReaderFor<T> Orphan<T>::getReader() const {
return _::OrphanGetImpl<T>::applyReader(builder);
}
template <typename T>
struct Orphanage::GetInnerBuilder<T, Kind::STRUCT> {
static inline _::StructBuilder apply(typename T::Builder& t) {
return t._builder;
}
};
template <typename T>
struct Orphanage::GetInnerBuilder<T, Kind::LIST> {
static inline _::ListBuilder apply(typename T::Builder& t) {
return t.builder;
}
};
template <typename BuilderType>
Orphanage Orphanage::getForMessageContaining(BuilderType builder) {
return Orphanage(GetInnerBuilder<FromBuilder<BuilderType>>::apply(builder).getArena());
}
template <typename RootType>
Orphan<RootType> Orphanage::newOrphan() const {
return Orphan<RootType>(_::OrphanBuilder::initStruct(arena, _::structSize<RootType>()));
}
template <typename T, Kind k>
struct Orphanage::NewOrphanListImpl<List<T, k>> {
static inline _::OrphanBuilder apply(_::BuilderArena* arena, uint size) {
return _::OrphanBuilder::initList(arena, size * ELEMENTS, _::ElementSizeForType<T>::value);
}
};
template <typename T>
struct Orphanage::NewOrphanListImpl<List<T, Kind::STRUCT>> {
static inline _::OrphanBuilder apply(_::BuilderArena* arena, uint size) {
return _::OrphanBuilder::initStructList(arena, size * ELEMENTS, _::structSize<T>());
}
};
template <>
struct Orphanage::NewOrphanListImpl<Text> {
static inline _::OrphanBuilder apply(_::BuilderArena* arena, uint size) {
return _::OrphanBuilder::initText(arena, size * BYTES);
}
};
template <>
struct Orphanage::NewOrphanListImpl<Data> {
static inline _::OrphanBuilder apply(_::BuilderArena* arena, uint size) {
return _::OrphanBuilder::initData(arena, size * BYTES);
}
};
template <typename RootType>
Orphan<RootType> Orphanage::newOrphan(uint size) const {
return Orphan<RootType>(NewOrphanListImpl<RootType>::apply(arena, size));
}
template <typename T>
struct Orphanage::GetInnerReader<T, Kind::STRUCT> {
static inline _::StructReader apply(const typename T::Reader& t) {
return t._reader;
}
};
template <typename T>
struct Orphanage::GetInnerReader<T, Kind::LIST> {
static inline _::ListReader apply(const typename T::Reader& t) {
return t.reader;
}
};
template <typename T>
struct Orphanage::GetInnerReader<T, Kind::BLOB> {
static inline const typename T::Reader& apply(const typename T::Reader& t) {
return t;
}
};
template <typename Reader>
inline Orphan<FromReader<Reader>> Orphanage::newOrphanCopy(const Reader& copyFrom) const {
return Orphan<FromReader<Reader>>(_::OrphanBuilder::copy(
arena, GetInnerReader<FromReader<Reader>>::apply(copyFrom)));
}
template <typename Reader>
inline Orphan<FromReader<Reader>> Orphanage::newOrphanCopy(Reader& copyFrom) const {
return newOrphanCopy(kj::implicitCast<const Reader&>(copyFrom));
}
} // namespace capnp
#endif // CAPNP_ORPHAN_H_
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