// Protocol Buffers - Google's data interchange format
// Copyright 2008 Google Inc. All rights reserved.
// https://developers.google.com/protocol-buffers/
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * 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.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// 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.
// This file defines an Arena allocator for better allocation performance.
#ifndef GOOGLE_PROTOBUF_ARENA_H__
#define GOOGLE_PROTOBUF_ARENA_H__
#include <limits>
#ifdef max
#undef max // Visual Studio defines this macro
#endif
#if __cplusplus >= 201103L
#include <google/protobuf/stubs/type_traits.h>
#endif
#if defined(_MSC_VER) && !_HAS_EXCEPTIONS
// Work around bugs in MSVC <typeinfo> header when _HAS_EXCEPTIONS=0.
#include <exception>
#include <typeinfo>
namespace std {
using type_info = ::type_info;
}
#else
#include <typeinfo>
#endif
#include <google/protobuf/stubs/atomic_sequence_num.h>
#include <google/protobuf/stubs/atomicops.h>
#include <google/protobuf/stubs/common.h>
#include <google/protobuf/stubs/logging.h>
#include <google/protobuf/stubs/mutex.h>
#include <google/protobuf/stubs/type_traits.h>
namespace google {
namespace protobuf {
class Arena; // defined below
class Message; // message.h
namespace internal {
class ArenaString; // arenastring.h
class LazyField; // lazy_field.h
template<typename Type>
class GenericTypeHandler; // repeated_field.h
// Templated cleanup methods.
template<typename T> void arena_destruct_object(void* object) {
reinterpret_cast<T*>(object)->~T();
}
template<typename T> void arena_delete_object(void* object) {
delete reinterpret_cast<T*>(object);
}
inline void arena_free(void* object, size_t size) {
#if defined(__GXX_DELETE_WITH_SIZE__) || defined(__cpp_sized_deallocation)
::operator delete(object, size);
#else
(void)size;
::operator delete(object);
#endif
}
} // namespace internal
// ArenaOptions provides optional additional parameters to arena construction
// that control its block-allocation behavior.
struct ArenaOptions {
// This defines the size of the first block requested from the system malloc.
// Subsequent block sizes will increase in a geometric series up to a maximum.
size_t start_block_size;
// This defines the maximum block size requested from system malloc (unless an
// individual arena allocation request occurs with a size larger than this
// maximum). Requested block sizes increase up to this value, then remain
// here.
size_t max_block_size;
// An initial block of memory for the arena to use, or NULL for none. If
// provided, the block must live at least as long as the arena itself. The
// creator of the Arena retains ownership of the block after the Arena is
// destroyed.
char* initial_block;
// The size of the initial block, if provided.
size_t initial_block_size;
// A function pointer to an alloc method that returns memory blocks of size
// requested. By default, it contains a ptr to the malloc function.
//
// NOTE: block_alloc and dealloc functions are expected to behave like
// malloc and free, including Asan poisoning.
void* (*block_alloc)(size_t);
// A function pointer to a dealloc method that takes ownership of the blocks
// from the arena. By default, it contains a ptr to a wrapper function that
// calls free.
void (*block_dealloc)(void*, size_t);
// Hooks for adding external functionality such as user-specific metrics
// collection, specific debugging abilities, etc.
// Init hook may return a pointer to a cookie to be stored in the arena.
// reset and destruction hooks will then be called with the same cookie
// pointer. This allows us to save an external object per arena instance and
// use it on the other hooks (Note: It is just as legal for init to return
// NULL and not use the cookie feature).
// on_arena_reset and on_arena_destruction also receive the space used in
// the arena just before the reset.
void* (*on_arena_init)(Arena* arena);
void (*on_arena_reset)(Arena* arena, void* cookie, uint64 space_used);
void (*on_arena_destruction)(Arena* arena, void* cookie, uint64 space_used);
// type_info is promised to be static - its lifetime extends to
// match program's lifetime (It is given by typeid operator).
// Note: typeid(void) will be passed as allocated_type every time we
// intentionally want to avoid monitoring an allocation. (i.e. internal
// allocations for managing the arena)
void (*on_arena_allocation)(const std::type_info* allocated_type,
uint64 alloc_size, void* cookie);
ArenaOptions()
: start_block_size(kDefaultStartBlockSize),
max_block_size(kDefaultMaxBlockSize),
initial_block(NULL),
initial_block_size(0),
block_alloc(&::operator new),
block_dealloc(&internal::arena_free),
on_arena_init(NULL),
on_arena_reset(NULL),
on_arena_destruction(NULL),
on_arena_allocation(NULL) {}
private:
// Constants define default starting block size and max block size for
// arena allocator behavior -- see descriptions above.
static const size_t kDefaultStartBlockSize = 256;
static const size_t kDefaultMaxBlockSize = 8192;
};
// Support for non-RTTI environments. (The metrics hooks API uses type
// information.)
#ifndef GOOGLE_PROTOBUF_NO_RTTI
#define RTTI_TYPE_ID(type) (&typeid(type))
#else
#define RTTI_TYPE_ID(type) (NULL)
#endif
// Arena allocator. Arena allocation replaces ordinary (heap-based) allocation
// with new/delete, and improves performance by aggregating allocations into
// larger blocks and freeing allocations all at once. Protocol messages are
// allocated on an arena by using Arena::CreateMessage<T>(Arena*), below, and
// are automatically freed when the arena is destroyed.
//
// This is a thread-safe implementation: multiple threads may allocate from the
// arena concurrently. Destruction is not thread-safe and the destructing
// thread must synchronize with users of the arena first.
//
// An arena provides two allocation interfaces: CreateMessage<T>, which works
// for arena-enabled proto2 message types as well as other types that satisfy
// the appropriate protocol (described below), and Create<T>, which works for
// any arbitrary type T. CreateMessage<T> is better when the type T supports it,
// because this interface (i) passes the arena pointer to the created object so
// that its sub-objects and internal allocations can use the arena too, and (ii)
// elides the object's destructor call when possible. Create<T> does not place
// any special requirements on the type T, and will invoke the object's
// destructor when the arena is destroyed.
//
// The arena message allocation protocol, required by CreateMessage<T>, is as
// follows:
//
// - The type T must have (at least) two constructors: a constructor with no
// arguments, called when a T is allocated on the heap; and a constructor with
// a google::protobuf::Arena* argument, called when a T is allocated on an arena. If the
// second constructor is called with a NULL arena pointer, it must be
// equivalent to invoking the first (no-argument) constructor.
//
// - The type T must have a particular type trait: a nested type
// |InternalArenaConstructable_|. This is usually a typedef to |void|. If no
// such type trait exists, then the instantiation CreateMessage<T> will fail
// to compile.
//
// - The type T *may* have the type trait |DestructorSkippable_|. If this type
// trait is present in the type, then its destructor will not be called if and
// only if it was passed a non-NULL arena pointer. If this type trait is not
// present on the type, then its destructor is always called when the
// containing arena is destroyed.
//
// - One- and two-user-argument forms of CreateMessage<T>() also exist that
// forward these constructor arguments to T's constructor: for example,
// CreateMessage<T>(Arena*, arg1, arg2) forwards to a constructor T(Arena*,
// arg1, arg2).
//
// This protocol is implemented by all arena-enabled proto2 message classes as
// well as RepeatedPtrField.
//
// Do NOT subclass Arena. This class will be marked as final when C++11 is
// enabled.
class LIBPROTOBUF_EXPORT Arena {
public:
// Arena constructor taking custom options. See ArenaOptions below for
// descriptions of the options available.
explicit Arena(const ArenaOptions& options) : options_(options) {
Init();
}
// Default constructor with sensible default options, tuned for average
// use-cases.
Arena() {
Init();
}
// Destructor deletes all owned heap allocated objects, and destructs objects
// that have non-trivial destructors, except for proto2 message objects whose
// destructors can be skipped. Also, frees all blocks except the initial block
// if it was passed in.
~Arena();
// API to create proto2 message objects on the arena. If the arena passed in
// is NULL, then a heap allocated object is returned. Type T must be a message
// defined in a .proto file with cc_enable_arenas set to true, otherwise a
// compilation error will occur.
//
// RepeatedField and RepeatedPtrField may also be instantiated directly on an
// arena with this method.
//
// This function also accepts any type T that satisfies the arena message
// allocation protocol, documented above.
template <typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
static T* CreateMessage(::google::protobuf::Arena* arena) {
if (arena == NULL) {
return new T;
} else {
return arena->CreateMessageInternal<T>(static_cast<T*>(0));
}
}
// One-argument form of CreateMessage. This is useful for constructing objects
// that implement the arena message construction protocol described above but
// take additional constructor arguments.
template <typename T, typename Arg> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
static T* CreateMessage(::google::protobuf::Arena* arena, const Arg& arg) {
if (arena == NULL) {
return new T(NULL, arg);
} else {
return arena->CreateMessageInternal<T>(static_cast<T*>(0),
arg);
}
}
// Two-argument form of CreateMessage. This is useful for constructing objects
// that implement the arena message construction protocol described above but
// take additional constructor arguments.
template <typename T, typename Arg1, typename Arg2> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
static T* CreateMessage(::google::protobuf::Arena* arena,
const Arg1& arg1,
const Arg2& arg2) {
if (arena == NULL) {
return new T(NULL, arg1, arg2);
} else {
return arena->CreateMessageInternal<T>(static_cast<T*>(0),
arg1, arg2);
}
}
// API to create any objects on the arena. Note that only the object will
// be created on the arena; the underlying ptrs (in case of a proto2 message)
// will be still heap allocated. Proto messages should usually be allocated
// with CreateMessage<T>() instead.
//
// Note that even if T satisfies the arena message construction protocol
// (InternalArenaConstructable_ trait and optional DestructorSkippable_
// trait), as described above, this function does not follow the protocol;
// instead, it treats T as a black-box type, just as if it did not have these
// traits. Specifically, T's constructor arguments will always be only those
// passed to Create<T>() -- no additional arena pointer is implicitly added.
// Furthermore, the destructor will always be called at arena destruction time
// (unless the destructor is trivial). Hence, from T's point of view, it is as
// if the object were allocated on the heap (except that the underlying memory
// is obtained from the arena).
#if LANG_CXX11
template <typename T, typename... Args> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
static T* Create(::google::protobuf::Arena* arena, Args&&... args) {
if (arena == NULL) {
return new T(std::forward<Args>(args)...);
} else {
return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value,
std::forward<Args>(args)...);
}
}
#endif
template <typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
static T* Create(::google::protobuf::Arena* arena) {
if (arena == NULL) {
return new T();
} else {
return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value);
}
}
// Version of the above with one constructor argument for the created object.
template <typename T, typename Arg> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
static T* Create(::google::protobuf::Arena* arena, const Arg& arg) {
if (arena == NULL) {
return new T(arg);
} else {
return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value,
arg);
}
}
// Version of the above with two constructor arguments for the created object.
template <typename T, typename Arg1, typename Arg2> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
static T* Create(::google::protobuf::Arena* arena, const Arg1& arg1, const Arg2& arg2) {
if (arena == NULL) {
return new T(arg1, arg2);
} else {
return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value,
arg1, arg2);
}
}
// Version of the above with three constructor arguments for the created
// object.
template <typename T, typename Arg1, typename Arg2, typename Arg3>
GOOGLE_ATTRIBUTE_ALWAYS_INLINE static T* Create(::google::protobuf::Arena* arena,
const Arg1& arg1, const Arg2& arg2,
const Arg3& arg3) {
if (arena == NULL) {
return new T(arg1, arg2, arg3);
} else {
return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value,
arg1, arg2, arg3);
}
}
// Version of the above with four constructor arguments for the created
// object.
template <typename T, typename Arg1, typename Arg2, typename Arg3,
typename Arg4>
GOOGLE_ATTRIBUTE_ALWAYS_INLINE static T* Create(::google::protobuf::Arena* arena,
const Arg1& arg1, const Arg2& arg2,
const Arg3& arg3, const Arg4& arg4) {
if (arena == NULL) {
return new T(arg1, arg2, arg3, arg4);
} else {
return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value,
arg1, arg2, arg3, arg4);
}
}
// Version of the above with five constructor arguments for the created
// object.
template <typename T, typename Arg1, typename Arg2, typename Arg3,
typename Arg4, typename Arg5>
GOOGLE_ATTRIBUTE_ALWAYS_INLINE static T* Create(::google::protobuf::Arena* arena,
const Arg1& arg1, const Arg2& arg2,
const Arg3& arg3, const Arg4& arg4,
const Arg5& arg5) {
if (arena == NULL) {
return new T(arg1, arg2, arg3, arg4, arg5);
} else {
return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value,
arg1, arg2, arg3, arg4, arg5);
}
}
// Version of the above with six constructor arguments for the created
// object.
template <typename T, typename Arg1, typename Arg2, typename Arg3,
typename Arg4, typename Arg5, typename Arg6>
GOOGLE_ATTRIBUTE_ALWAYS_INLINE static T* Create(::google::protobuf::Arena* arena,
const Arg1& arg1, const Arg2& arg2,
const Arg3& arg3, const Arg4& arg4,
const Arg5& arg5, const Arg6& arg6) {
if (arena == NULL) {
return new T(arg1, arg2, arg3, arg4, arg5, arg6);
} else {
return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value,
arg1, arg2, arg3, arg4, arg5, arg6);
}
}
// Version of the above with seven constructor arguments for the created
// object.
template <typename T, typename Arg1, typename Arg2, typename Arg3,
typename Arg4, typename Arg5, typename Arg6, typename Arg7>
GOOGLE_ATTRIBUTE_ALWAYS_INLINE static T* Create(::google::protobuf::Arena* arena,
const Arg1& arg1, const Arg2& arg2,
const Arg3& arg3, const Arg4& arg4,
const Arg5& arg5, const Arg6& arg6,
const Arg7& arg7) {
if (arena == NULL) {
return new T(arg1, arg2, arg3, arg4, arg5, arg6, arg7);
} else {
return arena->CreateInternal<T>(google::protobuf::internal::has_trivial_destructor<T>::value,
arg1, arg2, arg3, arg4, arg5, arg6, arg7);
}
}
// Version of the above with eight constructor arguments for the created
// object.
template <typename T, typename Arg1, typename Arg2, typename Arg3,
typename Arg4, typename Arg5, typename Arg6, typename Arg7,
typename Arg8>
GOOGLE_ATTRIBUTE_ALWAYS_INLINE static T* Create(::google::protobuf::Arena* arena,
const Arg1& arg1, const Arg2& arg2,
const Arg3& arg3, const Arg4& arg4,
const Arg5& arg5, const Arg6& arg6,
const Arg7& arg7, const Arg8& arg8) {
if (arena == NULL) {
return new T(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);
} else {
return arena->CreateInternal<T>(
google::protobuf::internal::has_trivial_destructor<T>::value,
arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);
}
}
// Create an array of object type T on the arena *without* invoking the
// constructor of T. If `arena` is null, then the return value should be freed
// with `delete[] x;` (or `::operator delete[](x);`).
// To ensure safe uses, this function checks at compile time
// (when compiled as C++11) that T is trivially default-constructible and
// trivially destructible.
template <typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
static T* CreateArray(::google::protobuf::Arena* arena, size_t num_elements) {
GOOGLE_CHECK_LE(num_elements,
std::numeric_limits<size_t>::max() / sizeof(T))
<< "Requested size is too large to fit into size_t.";
if (arena == NULL) {
return static_cast<T*>(::operator new[](num_elements * sizeof(T)));
} else {
return arena->CreateInternalRawArray<T>(num_elements);
}
}
// Returns the total space allocated by the arena, which is the sum of the
// sizes of the underlying blocks. This method is relatively fast; a counter
// is kept as blocks are allocated.
uint64 SpaceAllocated() const;
// Returns the total space used by the arena. Similar to SpaceAllocated but
// does not include free space and block overhead. The total space returned
// may not include space used by other threads executing concurrently with
// the call to this method.
GOOGLE_ATTRIBUTE_NOINLINE uint64 SpaceUsed() const;
// DEPRECATED. Please use SpaceAllocated() and SpaceUsed().
//
// Combines SpaceAllocated and SpaceUsed. Returns a pair of
// <space_allocated, space_used>.
GOOGLE_ATTRIBUTE_NOINLINE std::pair<uint64, uint64> SpaceAllocatedAndUsed() const;
// Frees all storage allocated by this arena after calling destructors
// registered with OwnDestructor() and freeing objects registered with Own().
// Any objects allocated on this arena are unusable after this call. It also
// returns the total space used by the arena which is the sums of the sizes
// of the allocated blocks. This method is not thread-safe.
GOOGLE_ATTRIBUTE_NOINLINE uint64 Reset();
// Adds |object| to a list of heap-allocated objects to be freed with |delete|
// when the arena is destroyed or reset.
template <typename T> GOOGLE_ATTRIBUTE_NOINLINE
void Own(T* object) {
OwnInternal(object, google::protobuf::internal::is_convertible<T*, ::google::protobuf::Message*>());
}
// Adds |object| to a list of objects whose destructors will be manually
// called when the arena is destroyed or reset. This differs from Own() in
// that it does not free the underlying memory with |delete|; hence, it is
// normally only used for objects that are placement-newed into
// arena-allocated memory.
template <typename T> GOOGLE_ATTRIBUTE_NOINLINE
void OwnDestructor(T* object) {
if (object != NULL) {
AddListNode(object, &internal::arena_destruct_object<T>);
}
}
// Adds a custom member function on an object to the list of destructors that
// will be manually called when the arena is destroyed or reset. This differs
// from OwnDestructor() in that any member function may be specified, not only
// the class destructor.
GOOGLE_ATTRIBUTE_NOINLINE void OwnCustomDestructor(void* object,
void (*destruct)(void*)) {
AddListNode(object, destruct);
}
// Retrieves the arena associated with |value| if |value| is an arena-capable
// message, or NULL otherwise. This differs from value->GetArena() in that the
// latter is a virtual call, while this method is a templated call that
// resolves at compile-time.
template<typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
static ::google::protobuf::Arena* GetArena(const T* value) {
return GetArenaInternal(value, static_cast<T*>(0));
}
private:
struct InternalIsArenaConstructableHelper {
template<typename U>
static char ArenaConstructable(
const typename U::InternalArenaConstructable_*);
template<typename U>
static double ArenaConstructable(...);
};
public:
// Helper typetrait that indicates support for arenas in a type T at compile
// time. This is public only to allow construction of higher-level templated
// utilities. is_arena_constructable<T>::value is true if the message type T
// has arena support enabled, and false otherwise.
//
// This is inside Arena because only Arena has the friend relationships
// necessary to see the underlying generated code traits.
template <typename T>
struct is_arena_constructable
: public google::protobuf::internal::integral_constant<
bool, sizeof(InternalIsArenaConstructableHelper::ArenaConstructable<
const T>(static_cast<const T*>(0))) == sizeof(char)> {
};
private:
// Blocks are variable length malloc-ed objects. The following structure
// describes the common header for all blocks.
struct Block {
void* owner; // &ThreadCache of thread that owns this block, or
// &this->owner if not yet owned by a thread.
Block* next; // Next block in arena (may have different owner)
// ((char*) &block) + pos is next available byte. It is always
// aligned at a multiple of 8 bytes.
size_t pos;
size_t size; // total size of the block.
GOOGLE_ATTRIBUTE_ALWAYS_INLINE size_t avail() const { return size - pos; }
// data follows
};
template<typename Type> friend class ::google::protobuf::internal::GenericTypeHandler;
friend class MockArena; // For unit-testing.
friend class internal::ArenaString; // For AllocateAligned.
friend class internal::LazyField; // For CreateMaybeMessage.
struct ThreadCache {
// The ThreadCache is considered valid as long as this matches the
// lifecycle_id of the arena being used.
int64 last_lifecycle_id_seen;
Block* last_block_used_;
};
static const size_t kHeaderSize = sizeof(Block);
static google::protobuf::internal::SequenceNumber lifecycle_id_generator_;
#if defined(GOOGLE_PROTOBUF_NO_THREADLOCAL)
// Android ndk does not support GOOGLE_THREAD_LOCAL keyword so we use a custom thread
// local storage class we implemented.
// iOS also does not support the GOOGLE_THREAD_LOCAL keyword.
static ThreadCache& thread_cache();
#elif defined(PROTOBUF_USE_DLLS)
// Thread local variables cannot be exposed through DLL interface but we can
// wrap them in static functions.
static ThreadCache& thread_cache();
#else
static GOOGLE_THREAD_LOCAL ThreadCache thread_cache_;
static ThreadCache& thread_cache() { return thread_cache_; }
#endif
// SFINAE for skipping addition to delete list for a message type when created
// with CreateMessage. This is mainly to skip proto2/proto1 message objects
// with cc_enable_arenas=true from being part of the delete list. Also, note,
// compiler will optimize out the branch in CreateInternal<T>.
template<typename T>
static inline bool SkipDeleteList(typename T::DestructorSkippable_*) {
return true;
}
// For message objects that don't have the DestructorSkippable_ trait, we
// always add to the delete list.
template<typename T>
static inline bool SkipDeleteList(...) {
return google::protobuf::internal::has_trivial_destructor<T>::value;
}
private:
struct InternalIsDestructorSkippableHelper {
template<typename U>
static char DestructorSkippable(
const typename U::DestructorSkippable_*);
template<typename U>
static double DestructorSkippable(...);
};
public:
// Helper typetrait that indicates whether the desctructor of type T should be
// called when arena is destroyed at compile time. This is only to allow
// construction of higher-level templated utilities.
// is_destructor_skippable<T>::value is true if the destructor of the message
// type T should not be called when arena is destroyed or false otherwise.
// This is inside Arena because only Arena has the friend relationships
// necessary to see the underlying generated code traits.
template<typename T>
struct is_destructor_skippable
: public google::protobuf::internal::integral_constant<
bool,
sizeof(InternalIsDestructorSkippableHelper::DestructorSkippable<
const T>(static_cast<const T*>(0))) == sizeof(char) ||
google::protobuf::internal::has_trivial_destructor<T>::value> {};
private:
// CreateMessage<T> requires that T supports arenas, but this private method
// works whether or not T supports arenas. These are not exposed to user code
// as it can cause confusing API usages, and end up having double free in
// user code. These are used only internally from LazyField and Repeated
// fields, since they are designed to work in all mode combinations.
template<typename Msg> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
static Msg* CreateMaybeMessage(
Arena* arena, typename Msg::InternalArenaConstructable_*) {
return CreateMessage<Msg>(arena);
}
template<typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
static T* CreateMaybeMessage(Arena* arena, ...) {
return Create<T>(arena);
}
// Just allocate the required size for the given type assuming the
// type has a trivial constructor.
template<typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
T* CreateInternalRawArray(size_t num_elements) {
GOOGLE_CHECK_LE(num_elements,
std::numeric_limits<size_t>::max() / sizeof(T))
<< "Requested size is too large to fit into size_t.";
return static_cast<T*>(
AllocateAligned(RTTI_TYPE_ID(T), sizeof(T) * num_elements));
}
#if LANG_CXX11
template <typename T, typename... Args> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
T* CreateInternal(bool skip_explicit_ownership, Args&&... args) {
T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T)))
T(std::forward<Args>(args)...);
if (!skip_explicit_ownership) {
AddListNode(t, &internal::arena_destruct_object<T>);
}
return t;
}
#endif
template <typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
T* CreateInternal(bool skip_explicit_ownership) {
T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T))) T();
if (!skip_explicit_ownership) {
AddListNode(t, &internal::arena_destruct_object<T>);
}
return t;
}
template <typename T, typename Arg> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
T* CreateInternal(bool skip_explicit_ownership, const Arg& arg) {
T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T))) T(arg);
if (!skip_explicit_ownership) {
AddListNode(t, &internal::arena_destruct_object<T>);
}
return t;
}
template <typename T, typename Arg1, typename Arg2> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
T* CreateInternal(
bool skip_explicit_ownership, const Arg1& arg1, const Arg2& arg2) {
T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T))) T(arg1, arg2);
if (!skip_explicit_ownership) {
AddListNode(t, &internal::arena_destruct_object<T>);
}
return t;
}
template <typename T, typename Arg1, typename Arg2, typename Arg3>
GOOGLE_ATTRIBUTE_ALWAYS_INLINE T* CreateInternal(bool skip_explicit_ownership,
const Arg1& arg1,
const Arg2& arg2,
const Arg3& arg3) {
T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T)))
T(arg1, arg2, arg3);
if (!skip_explicit_ownership) {
AddListNode(t, &internal::arena_destruct_object<T>);
}
return t;
}
template <typename T, typename Arg1, typename Arg2, typename Arg3,
typename Arg4>
GOOGLE_ATTRIBUTE_ALWAYS_INLINE T* CreateInternal(bool skip_explicit_ownership,
const Arg1& arg1,
const Arg2& arg2,
const Arg3& arg3,
const Arg4& arg4) {
T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T)))
T(arg1, arg2, arg3, arg4);
if (!skip_explicit_ownership) {
AddListNode(t, &internal::arena_destruct_object<T>);
}
return t;
}
template <typename T, typename Arg1, typename Arg2, typename Arg3,
typename Arg4, typename Arg5>
GOOGLE_ATTRIBUTE_ALWAYS_INLINE T* CreateInternal(bool skip_explicit_ownership,
const Arg1& arg1,
const Arg2& arg2,
const Arg3& arg3,
const Arg4& arg4,
const Arg5& arg5) {
T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T)))
T(arg1, arg2, arg3, arg4, arg5);
if (!skip_explicit_ownership) {
AddListNode(t, &internal::arena_destruct_object<T>);
}
return t;
}
template <typename T, typename Arg1, typename Arg2, typename Arg3,
typename Arg4, typename Arg5, typename Arg6>
GOOGLE_ATTRIBUTE_ALWAYS_INLINE T* CreateInternal(bool skip_explicit_ownership,
const Arg1& arg1,
const Arg2& arg2,
const Arg3& arg3,
const Arg4& arg4,
const Arg5& arg5,
const Arg6& arg6) {
T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T)))
T(arg1, arg2, arg3, arg4, arg5, arg6);
if (!skip_explicit_ownership) {
AddListNode(t, &internal::arena_destruct_object<T>);
}
return t;
}
template <typename T, typename Arg1, typename Arg2, typename Arg3,
typename Arg4, typename Arg5, typename Arg6, typename Arg7>
GOOGLE_ATTRIBUTE_ALWAYS_INLINE T* CreateInternal(bool skip_explicit_ownership,
const Arg1& arg1,
const Arg2& arg2,
const Arg3& arg3,
const Arg4& arg4,
const Arg5& arg5,
const Arg6& arg6,
const Arg7& arg7) {
T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T)))
T(arg1, arg2, arg3, arg4, arg5, arg6, arg7);
if (!skip_explicit_ownership) {
AddListNode(t, &internal::arena_destruct_object<T>);
}
return t;
}
template <typename T, typename Arg1, typename Arg2, typename Arg3,
typename Arg4, typename Arg5, typename Arg6, typename Arg7,
typename Arg8>
GOOGLE_ATTRIBUTE_ALWAYS_INLINE T* CreateInternal(bool skip_explicit_ownership,
const Arg1& arg1,
const Arg2& arg2,
const Arg3& arg3,
const Arg4& arg4,
const Arg5& arg5,
const Arg6& arg6,
const Arg7& arg7,
const Arg8& arg8) {
T* t = new (AllocateAligned(RTTI_TYPE_ID(T), sizeof(T)))
T(arg1, arg2, arg3, arg4, arg5, arg6, arg7, arg8);
if (!skip_explicit_ownership) {
AddListNode(t, &internal::arena_destruct_object<T>);
}
return t;
}
template <typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
T* CreateMessageInternal(typename T::InternalArenaConstructable_*) {
return CreateInternal<T>(SkipDeleteList<T>(static_cast<T*>(0)), this);
}
template <typename T, typename Arg> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
T* CreateMessageInternal(typename T::InternalArenaConstructable_*,
const Arg& arg) {
return CreateInternal<T>(SkipDeleteList<T>(static_cast<T*>(0)), this, arg);
}
template <typename T, typename Arg1, typename Arg2> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
T* CreateMessageInternal(typename T::InternalArenaConstructable_*,
const Arg1& arg1, const Arg2& arg2) {
return CreateInternal<T>(SkipDeleteList<T>(static_cast<T*>(0)), this, arg1,
arg2);
}
// CreateInArenaStorage is used to implement map field. Without it,
// google::protobuf::Map need to call generated message's protected arena constructor,
// which needs to declare google::protobuf::Map as friend of generated message.
template <typename T>
static void CreateInArenaStorage(T* ptr, Arena* arena) {
CreateInArenaStorageInternal(ptr, arena,
typename is_arena_constructable<T>::type());
RegisterDestructorInternal(ptr, arena,
typename is_destructor_skippable<T>::type());
}
template <typename T>
static void CreateInArenaStorageInternal(
T* ptr, Arena* arena, google::protobuf::internal::true_type) {
new (ptr) T(arena);
}
template <typename T>
static void CreateInArenaStorageInternal(
T* ptr, Arena* /* arena */, google::protobuf::internal::false_type) {
new (ptr) T();
}
template <typename T>
static void RegisterDestructorInternal(
T* /* ptr */, Arena* /* arena */, google::protobuf::internal::true_type) {}
template <typename T>
static void RegisterDestructorInternal(
T* ptr, Arena* arena, google::protobuf::internal::false_type) {
arena->OwnDestructor(ptr);
}
// These implement Own(), which registers an object for deletion (destructor
// call and operator delete()). The second parameter has type 'true_type' if T
// is a subtype of ::google::protobuf::Message and 'false_type' otherwise. Collapsing
// all template instantiations to one for generic Message reduces code size,
// using the virtual destructor instead.
template<typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
void OwnInternal(T* object, google::protobuf::internal::true_type) {
if (object != NULL) {
AddListNode(object, &internal::arena_delete_object< ::google::protobuf::Message >);
}
}
template<typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
void OwnInternal(T* object, google::protobuf::internal::false_type) {
if (object != NULL) {
AddListNode(object, &internal::arena_delete_object<T>);
}
}
// Implementation for GetArena(). Only message objects with
// InternalArenaConstructable_ tags can be associated with an arena, and such
// objects must implement a GetArenaNoVirtual() method.
template<typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
static ::google::protobuf::Arena* GetArenaInternal(
const T* value, typename T::InternalArenaConstructable_*) {
return value->GetArenaNoVirtual();
}
template<typename T> GOOGLE_ATTRIBUTE_ALWAYS_INLINE
static ::google::protobuf::Arena* GetArenaInternal(const T* /* value */, ...) {
return NULL;
}
// Allocate and also optionally call on_arena_allocation callback with the
// allocated type info when the hooks are in place in ArenaOptions and
// the cookie is not null.
void* AllocateAligned(const std::type_info* allocated, size_t n);
// Allocate an internal allocation, avoiding optional typed monitoring.
GOOGLE_ATTRIBUTE_ALWAYS_INLINE void* AllocateAligned(size_t n) {
return AllocateAligned(NULL, n);
}
void Init();
// Free all blocks and return the total space used which is the sums of sizes
// of the all the allocated blocks.
uint64 FreeBlocks();
// Add object pointer and cleanup function pointer to the list.
// TODO(rohananil, cfallin): We could pass in a sub-arena into this method
// to avoid polluting blocks of this arena with list nodes. This would help in
// mixed mode (where many protobufs have cc_enable_arenas=false), and is an
// alternative to a chunked linked-list, but with extra overhead of *next.
void AddListNode(void* elem, void (*cleanup)(void*));
// Delete or Destruct all objects owned by the arena.
void CleanupList();
uint64 ResetInternal();
inline void SetThreadCacheBlock(Block* block) {
thread_cache().last_block_used_ = block;
thread_cache().last_lifecycle_id_seen = lifecycle_id_;
}
int64 lifecycle_id_; // Unique for each arena. Changes on Reset().
google::protobuf::internal::AtomicWord blocks_; // Head of linked list of all allocated blocks
google::protobuf::internal::AtomicWord hint_; // Fast thread-local block access
uint64 space_allocated_; // Sum of sizes of all allocated blocks.
// Node contains the ptr of the object to be cleaned up and the associated
// cleanup function ptr.
struct Node {
void* elem; // Pointer to the object to be cleaned up.
void (*cleanup)(void*); // Function pointer to the destructor or deleter.
Node* next; // Next node in the list.
};
google::protobuf::internal::AtomicWord cleanup_list_; // Head of a linked list of nodes containing object
// ptrs and cleanup methods.
bool owns_first_block_; // Indicates that arena owns the first block
mutable Mutex blocks_lock_;
void AddBlock(Block* b);
// Access must be synchronized, either by blocks_lock_ or by being called from
// Init()/Reset().
void AddBlockInternal(Block* b);
void* SlowAlloc(size_t n);
Block* FindBlock(void* me);
Block* NewBlock(void* me, Block* my_last_block, size_t n,
size_t start_block_size, size_t max_block_size);
static void* AllocFromBlock(Block* b, size_t n);
template <typename Key, typename T>
friend class Map;
// The arena may save a cookie it receives from the external on_init hook
// and then use it when calling the on_reset and on_destruction hooks.
void* hooks_cookie_;
ArenaOptions options_;
GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(Arena);
};
// Defined above for supporting environments without RTTI.
#undef RTTI_TYPE_ID
} // namespace protobuf
} // namespace google
#endif // GOOGLE_PROTOBUF_ARENA_H__