737 lines
31 KiB
C++
737 lines
31 KiB
C++
// Protocol Buffers - Google's data interchange format
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// Copyright 2008 Google Inc. All rights reserved.
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// https://developers.google.com/protocol-buffers/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// This file defines an Arena allocator for better allocation performance.
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#ifndef GOOGLE_PROTOBUF_ARENA_H__
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#define GOOGLE_PROTOBUF_ARENA_H__
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#include <limits>
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#include <type_traits>
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#include <utility>
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#ifdef max
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#undef max // Visual Studio defines this macro
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#endif
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#if defined(_MSC_VER) && !defined(_LIBCPP_STD_VER) && !_HAS_EXCEPTIONS
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// Work around bugs in MSVC <typeinfo> header when _HAS_EXCEPTIONS=0.
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#include <exception>
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#include <typeinfo>
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namespace std {
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using type_info = ::type_info;
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}
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#else
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#include <typeinfo>
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#endif
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#include <type_traits>
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#include <google/protobuf/arena_impl.h>
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#include <google/protobuf/port.h>
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#include <google/protobuf/port_def.inc>
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#ifdef SWIG
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#error "You cannot SWIG proto headers"
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#endif
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namespace google {
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namespace protobuf {
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struct ArenaOptions; // defined below
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} // namespace protobuf
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} // namespace google
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namespace google {
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namespace protobuf {
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class Arena; // defined below
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class Message; // defined in message.h
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class MessageLite;
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template <typename Key, typename T>
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class Map;
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namespace arena_metrics {
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void EnableArenaMetrics(ArenaOptions* options);
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} // namespace arena_metrics
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namespace internal {
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struct ArenaStringPtr; // defined in arenastring.h
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class LazyField; // defined in lazy_field.h
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class EpsCopyInputStream; // defined in parse_context.h
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template <typename Type>
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class GenericTypeHandler; // defined in repeated_field.h
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// Templated cleanup methods.
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template <typename T>
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void arena_destruct_object(void* object) {
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reinterpret_cast<T*>(object)->~T();
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}
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template <typename T>
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void arena_delete_object(void* object) {
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delete reinterpret_cast<T*>(object);
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}
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inline void arena_free(void* object, size_t size) {
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#if defined(__GXX_DELETE_WITH_SIZE__) || defined(__cpp_sized_deallocation)
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::operator delete(object, size);
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#else
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(void)size;
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::operator delete(object);
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#endif
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}
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} // namespace internal
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// ArenaOptions provides optional additional parameters to arena construction
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// that control its block-allocation behavior.
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struct ArenaOptions {
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// This defines the size of the first block requested from the system malloc.
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// Subsequent block sizes will increase in a geometric series up to a maximum.
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size_t start_block_size;
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// This defines the maximum block size requested from system malloc (unless an
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// individual arena allocation request occurs with a size larger than this
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// maximum). Requested block sizes increase up to this value, then remain
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// here.
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size_t max_block_size;
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// An initial block of memory for the arena to use, or NULL for none. If
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// provided, the block must live at least as long as the arena itself. The
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// creator of the Arena retains ownership of the block after the Arena is
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// destroyed.
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char* initial_block;
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// The size of the initial block, if provided.
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size_t initial_block_size;
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// A function pointer to an alloc method that returns memory blocks of size
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// requested. By default, it contains a ptr to the malloc function.
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//
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// NOTE: block_alloc and dealloc functions are expected to behave like
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// malloc and free, including Asan poisoning.
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void* (*block_alloc)(size_t);
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// A function pointer to a dealloc method that takes ownership of the blocks
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// from the arena. By default, it contains a ptr to a wrapper function that
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// calls free.
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void (*block_dealloc)(void*, size_t);
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ArenaOptions()
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: start_block_size(kDefaultStartBlockSize),
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max_block_size(kDefaultMaxBlockSize),
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initial_block(NULL),
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initial_block_size(0),
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block_alloc(&::operator new),
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block_dealloc(&internal::arena_free),
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on_arena_init(NULL),
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on_arena_reset(NULL),
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on_arena_destruction(NULL),
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on_arena_allocation(NULL) {}
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private:
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// Hooks for adding external functionality such as user-specific metrics
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// collection, specific debugging abilities, etc.
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// Init hook (if set) will always be called at Arena init time. Init hook may
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// return a pointer to a cookie to be stored in the arena. Reset and
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// destruction hooks will then be called with the same cookie pointer. This
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// allows us to save an external object per arena instance and use it on the
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// other hooks (Note: If init hook returns NULL, the other hooks will NOT be
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// called on this arena instance).
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// on_arena_reset and on_arena_destruction also receive the space used in the
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// arena just before the reset.
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void* (*on_arena_init)(Arena* arena);
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void (*on_arena_reset)(Arena* arena, void* cookie, uint64 space_used);
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void (*on_arena_destruction)(Arena* arena, void* cookie, uint64 space_used);
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// type_info is promised to be static - its lifetime extends to
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// match program's lifetime (It is given by typeid operator).
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// Note: typeid(void) will be passed as allocated_type every time we
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// intentionally want to avoid monitoring an allocation. (i.e. internal
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// allocations for managing the arena)
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void (*on_arena_allocation)(const std::type_info* allocated_type,
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uint64 alloc_size, void* cookie);
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// Constants define default starting block size and max block size for
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// arena allocator behavior -- see descriptions above.
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static const size_t kDefaultStartBlockSize = 256;
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static const size_t kDefaultMaxBlockSize = 8192;
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friend void arena_metrics::EnableArenaMetrics(ArenaOptions*);
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friend class Arena;
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friend class ArenaOptionsTestFriend;
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};
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// Support for non-RTTI environments. (The metrics hooks API uses type
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// information.)
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#if PROTOBUF_RTTI
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#define RTTI_TYPE_ID(type) (&typeid(type))
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#else
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#define RTTI_TYPE_ID(type) (NULL)
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#endif
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// Arena allocator. Arena allocation replaces ordinary (heap-based) allocation
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// with new/delete, and improves performance by aggregating allocations into
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// larger blocks and freeing allocations all at once. Protocol messages are
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// allocated on an arena by using Arena::CreateMessage<T>(Arena*), below, and
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// are automatically freed when the arena is destroyed.
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//
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// This is a thread-safe implementation: multiple threads may allocate from the
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// arena concurrently. Destruction is not thread-safe and the destructing
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// thread must synchronize with users of the arena first.
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//
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// An arena provides two allocation interfaces: CreateMessage<T>, which works
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// for arena-enabled proto2 message types as well as other types that satisfy
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// the appropriate protocol (described below), and Create<T>, which works for
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// any arbitrary type T. CreateMessage<T> is better when the type T supports it,
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// because this interface (i) passes the arena pointer to the created object so
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// that its sub-objects and internal allocations can use the arena too, and (ii)
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// elides the object's destructor call when possible. Create<T> does not place
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// any special requirements on the type T, and will invoke the object's
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// destructor when the arena is destroyed.
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//
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// The arena message allocation protocol, required by
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// CreateMessage<T>(Arena* arena, Args&&... args), is as follows:
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//
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// - The type T must have (at least) two constructors: a constructor callable
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// with `args` (without `arena`), called when a T is allocated on the heap;
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// and a constructor callable with `Arena* arena, Args&&... args`, called when
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// a T is allocated on an arena. If the second constructor is called with a
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// NULL arena pointer, it must be equivalent to invoking the first
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// (`args`-only) constructor.
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//
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// - The type T must have a particular type trait: a nested type
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// |InternalArenaConstructable_|. This is usually a typedef to |void|. If no
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// such type trait exists, then the instantiation CreateMessage<T> will fail
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// to compile.
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//
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// - The type T *may* have the type trait |DestructorSkippable_|. If this type
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// trait is present in the type, then its destructor will not be called if and
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// only if it was passed a non-NULL arena pointer. If this type trait is not
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// present on the type, then its destructor is always called when the
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// containing arena is destroyed.
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//
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// This protocol is implemented by all arena-enabled proto2 message classes as
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// well as protobuf container types like RepeatedPtrField and Map. The protocol
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// is internal to protobuf and is not guaranteed to be stable. Non-proto types
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// should not rely on this protocol.
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class PROTOBUF_EXPORT PROTOBUF_ALIGNAS(8) Arena final {
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public:
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// Arena constructor taking custom options. See ArenaOptions below for
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// descriptions of the options available.
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explicit Arena(const ArenaOptions& options) : impl_(options) {
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Init(options);
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}
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// Block overhead. Use this as a guide for how much to over-allocate the
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// initial block if you want an allocation of size N to fit inside it.
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//
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// WARNING: if you allocate multiple objects, it is difficult to guarantee
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// that a series of allocations will fit in the initial block, especially if
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// Arena changes its alignment guarantees in the future!
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static const size_t kBlockOverhead = internal::ArenaImpl::kBlockHeaderSize +
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internal::ArenaImpl::kSerialArenaSize;
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// Default constructor with sensible default options, tuned for average
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// use-cases.
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Arena() : impl_(ArenaOptions()) { Init(ArenaOptions()); }
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~Arena() {
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if (hooks_cookie_) {
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CallDestructorHooks();
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}
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}
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void Init(const ArenaOptions& options) {
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on_arena_allocation_ = options.on_arena_allocation;
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on_arena_reset_ = options.on_arena_reset;
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on_arena_destruction_ = options.on_arena_destruction;
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// Call the initialization hook
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if (options.on_arena_init != NULL) {
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hooks_cookie_ = options.on_arena_init(this);
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} else {
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hooks_cookie_ = NULL;
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}
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}
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// API to create proto2 message objects on the arena. If the arena passed in
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// is NULL, then a heap allocated object is returned. Type T must be a message
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// defined in a .proto file with cc_enable_arenas set to true, otherwise a
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// compilation error will occur.
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//
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// RepeatedField and RepeatedPtrField may also be instantiated directly on an
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// arena with this method.
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//
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// This function also accepts any type T that satisfies the arena message
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// allocation protocol, documented above.
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template <typename T, typename... Args>
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PROTOBUF_ALWAYS_INLINE static T* CreateMessage(Arena* arena, Args&&... args) {
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static_assert(
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InternalHelper<T>::is_arena_constructable::value,
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"CreateMessage can only construct types that are ArenaConstructable");
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// We must delegate to CreateMaybeMessage() and NOT CreateMessageInternal()
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// because protobuf generated classes specialize CreateMaybeMessage() and we
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// need to use that specialization for code size reasons.
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return Arena::CreateMaybeMessage<T>(arena, std::forward<Args>(args)...);
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}
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// API to create any objects on the arena. Note that only the object will
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// be created on the arena; the underlying ptrs (in case of a proto2 message)
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// will be still heap allocated. Proto messages should usually be allocated
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// with CreateMessage<T>() instead.
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//
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// Note that even if T satisfies the arena message construction protocol
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// (InternalArenaConstructable_ trait and optional DestructorSkippable_
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// trait), as described above, this function does not follow the protocol;
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// instead, it treats T as a black-box type, just as if it did not have these
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// traits. Specifically, T's constructor arguments will always be only those
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// passed to Create<T>() -- no additional arena pointer is implicitly added.
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// Furthermore, the destructor will always be called at arena destruction time
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// (unless the destructor is trivial). Hence, from T's point of view, it is as
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// if the object were allocated on the heap (except that the underlying memory
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// is obtained from the arena).
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template <typename T, typename... Args>
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PROTOBUF_ALWAYS_INLINE static T* Create(Arena* arena, Args&&... args) {
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return CreateNoMessage<T>(arena, is_arena_constructable<T>(),
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std::forward<Args>(args)...);
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}
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// Create an array of object type T on the arena *without* invoking the
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// constructor of T. If `arena` is null, then the return value should be freed
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// with `delete[] x;` (or `::operator delete[](x);`).
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// To ensure safe uses, this function checks at compile time
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// (when compiled as C++11) that T is trivially default-constructible and
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// trivially destructible.
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template <typename T>
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PROTOBUF_ALWAYS_INLINE static T* CreateArray(Arena* arena,
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size_t num_elements) {
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static_assert(std::is_pod<T>::value,
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"CreateArray requires a trivially constructible type");
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static_assert(std::is_trivially_destructible<T>::value,
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"CreateArray requires a trivially destructible type");
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GOOGLE_CHECK_LE(num_elements, std::numeric_limits<size_t>::max() / sizeof(T))
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<< "Requested size is too large to fit into size_t.";
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if (arena == NULL) {
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return static_cast<T*>(::operator new[](num_elements * sizeof(T)));
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} else {
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return arena->CreateInternalRawArray<T>(num_elements);
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}
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}
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// Returns the total space allocated by the arena, which is the sum of the
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// sizes of the underlying blocks. This method is relatively fast; a counter
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// is kept as blocks are allocated.
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uint64 SpaceAllocated() const { return impl_.SpaceAllocated(); }
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// Returns the total space used by the arena. Similar to SpaceAllocated but
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// does not include free space and block overhead. The total space returned
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// may not include space used by other threads executing concurrently with
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// the call to this method.
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uint64 SpaceUsed() const { return impl_.SpaceUsed(); }
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// Frees all storage allocated by this arena after calling destructors
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// registered with OwnDestructor() and freeing objects registered with Own().
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// Any objects allocated on this arena are unusable after this call. It also
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// returns the total space used by the arena which is the sums of the sizes
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// of the allocated blocks. This method is not thread-safe.
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PROTOBUF_NOINLINE uint64 Reset() {
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// Call the reset hook
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if (on_arena_reset_ != NULL) {
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on_arena_reset_(this, hooks_cookie_, impl_.SpaceAllocated());
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}
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return impl_.Reset();
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}
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// Adds |object| to a list of heap-allocated objects to be freed with |delete|
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// when the arena is destroyed or reset.
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template <typename T>
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PROTOBUF_NOINLINE void Own(T* object) {
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OwnInternal(object, std::is_convertible<T*, Message*>());
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}
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// Adds |object| to a list of objects whose destructors will be manually
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// called when the arena is destroyed or reset. This differs from Own() in
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// that it does not free the underlying memory with |delete|; hence, it is
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// normally only used for objects that are placement-newed into
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// arena-allocated memory.
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template <typename T>
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PROTOBUF_NOINLINE void OwnDestructor(T* object) {
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if (object != NULL) {
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impl_.AddCleanup(object, &internal::arena_destruct_object<T>);
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}
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}
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// Adds a custom member function on an object to the list of destructors that
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// will be manually called when the arena is destroyed or reset. This differs
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// from OwnDestructor() in that any member function may be specified, not only
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// the class destructor.
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PROTOBUF_NOINLINE void OwnCustomDestructor(void* object,
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void (*destruct)(void*)) {
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impl_.AddCleanup(object, destruct);
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}
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// Retrieves the arena associated with |value| if |value| is an arena-capable
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// message, or NULL otherwise. If possible, the call resolves at compile time.
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// Note that we can often devirtualize calls to `value->GetArena()` so usually
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// calling this method is unnecessary.
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template <typename T>
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PROTOBUF_ALWAYS_INLINE static Arena* GetArena(const T* value) {
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return GetArenaInternal(value);
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}
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template <typename T>
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class InternalHelper {
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template <typename U>
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static char DestructorSkippable(const typename U::DestructorSkippable_*);
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template <typename U>
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static double DestructorSkippable(...);
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typedef std::integral_constant<
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bool, sizeof(DestructorSkippable<T>(static_cast<const T*>(0))) ==
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sizeof(char) ||
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std::is_trivially_destructible<T>::value>
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is_destructor_skippable;
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template <typename U>
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static char ArenaConstructable(
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const typename U::InternalArenaConstructable_*);
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template <typename U>
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static double ArenaConstructable(...);
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typedef std::integral_constant<bool, sizeof(ArenaConstructable<T>(
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static_cast<const T*>(0))) ==
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sizeof(char)>
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is_arena_constructable;
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template <typename U,
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typename std::enable_if<
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std::is_same<Arena*, decltype(std::declval<const U>()
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.GetArena())>::value,
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int>::type = 0>
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static char HasGetArena(decltype(&U::GetArena));
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template <typename U>
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static double HasGetArena(...);
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typedef std::integral_constant<bool, sizeof(HasGetArena<T>(nullptr)) ==
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sizeof(char)>
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has_get_arena;
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template <typename... Args>
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static T* Construct(void* ptr, Args&&... args) {
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return new (ptr) T(std::forward<Args>(args)...);
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}
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static Arena* GetArena(const T* p) { return p->GetArena(); }
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friend class Arena;
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};
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// Helper typetraits that indicates support for arenas in a type T at compile
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// time. This is public only to allow construction of higher-level templated
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// utilities.
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//
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// is_arena_constructable<T>::value is true if the message type T has arena
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// support enabled, and false otherwise.
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//
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// is_destructor_skippable<T>::value is true if the message type T has told
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// the arena that it is safe to skip the destructor, and false otherwise.
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//
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// This is inside Arena because only Arena has the friend relationships
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// necessary to see the underlying generated code traits.
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template <typename T>
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struct is_arena_constructable : InternalHelper<T>::is_arena_constructable {};
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template <typename T>
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struct is_destructor_skippable : InternalHelper<T>::is_destructor_skippable {
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};
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private:
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template <typename T>
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struct has_get_arena : InternalHelper<T>::has_get_arena {};
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template <typename T, typename... Args>
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PROTOBUF_ALWAYS_INLINE static T* CreateMessageInternal(Arena* arena,
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Args&&... args) {
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static_assert(
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InternalHelper<T>::is_arena_constructable::value,
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"CreateMessage can only construct types that are ArenaConstructable");
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if (arena == NULL) {
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return new T(nullptr, std::forward<Args>(args)...);
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} else {
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return arena->DoCreateMessage<T>(std::forward<Args>(args)...);
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}
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}
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// This specialization for no arguments is necessary, because its behavior is
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// slightly different. When the arena pointer is nullptr, it calls T()
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// instead of T(nullptr).
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template <typename T>
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PROTOBUF_ALWAYS_INLINE static T* CreateMessageInternal(Arena* arena) {
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static_assert(
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InternalHelper<T>::is_arena_constructable::value,
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"CreateMessage can only construct types that are ArenaConstructable");
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if (arena == NULL) {
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return new T();
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} else {
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return arena->DoCreateMessage<T>();
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}
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}
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template <typename T, typename... Args>
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PROTOBUF_ALWAYS_INLINE static T* CreateInternal(Arena* arena,
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Args&&... args) {
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if (arena == NULL) {
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return new T(std::forward<Args>(args)...);
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} else {
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return arena->DoCreate<T>(std::is_trivially_destructible<T>::value,
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std::forward<Args>(args)...);
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}
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}
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void CallDestructorHooks();
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void OnArenaAllocation(const std::type_info* allocated_type, size_t n) const;
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inline void AllocHook(const std::type_info* allocated_type, size_t n) const {
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if (PROTOBUF_PREDICT_FALSE(hooks_cookie_ != NULL)) {
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OnArenaAllocation(allocated_type, n);
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}
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}
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// Allocate and also optionally call on_arena_allocation callback with the
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// allocated type info when the hooks are in place in ArenaOptions and
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// the cookie is not null.
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template <typename T>
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PROTOBUF_ALWAYS_INLINE void* AllocateInternal(bool skip_explicit_ownership) {
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static_assert(alignof(T) <= 8, "T is overaligned, see b/151247138");
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const size_t n = internal::AlignUpTo8(sizeof(T));
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AllocHook(RTTI_TYPE_ID(T), n);
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// Monitor allocation if needed.
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if (skip_explicit_ownership) {
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return AllocateAlignedNoHook(n);
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} else {
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return impl_.AllocateAlignedAndAddCleanup(
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n, &internal::arena_destruct_object<T>);
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}
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}
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// CreateMessage<T> requires that T supports arenas, but this private method
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// works whether or not T supports arenas. These are not exposed to user code
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// as it can cause confusing API usages, and end up having double free in
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// user code. These are used only internally from LazyField and Repeated
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// fields, since they are designed to work in all mode combinations.
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template <typename Msg, typename... Args>
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PROTOBUF_ALWAYS_INLINE static Msg* DoCreateMaybeMessage(Arena* arena,
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|
std::true_type,
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|
Args&&... args) {
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return CreateMessageInternal<Msg>(arena, std::forward<Args>(args)...);
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}
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template <typename T, typename... Args>
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PROTOBUF_ALWAYS_INLINE static T* DoCreateMaybeMessage(Arena* arena,
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|
std::false_type,
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|
Args&&... args) {
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|
return CreateInternal<T>(arena, std::forward<Args>(args)...);
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|
}
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|
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|
template <typename T, typename... Args>
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|
PROTOBUF_ALWAYS_INLINE static T* CreateMaybeMessage(Arena* arena,
|
|
Args&&... args) {
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|
return DoCreateMaybeMessage<T>(arena, is_arena_constructable<T>(),
|
|
std::forward<Args>(args)...);
|
|
}
|
|
|
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template <typename T, typename... Args>
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|
PROTOBUF_ALWAYS_INLINE static T* CreateNoMessage(Arena* arena, std::true_type,
|
|
Args&&... args) {
|
|
// User is constructing with Create() despite the fact that T supports arena
|
|
// construction. In this case we have to delegate to CreateInternal(), and
|
|
// we can't use any CreateMaybeMessage() specialization that may be defined.
|
|
return CreateInternal<T>(arena, std::forward<Args>(args)...);
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|
}
|
|
|
|
template <typename T, typename... Args>
|
|
PROTOBUF_ALWAYS_INLINE static T* CreateNoMessage(Arena* arena,
|
|
std::false_type,
|
|
Args&&... args) {
|
|
// User is constructing with Create() and the type does not support arena
|
|
// construction. In this case we can delegate to CreateMaybeMessage() and
|
|
// use any specialization that may be available for that.
|
|
return CreateMaybeMessage<T>(arena, std::forward<Args>(args)...);
|
|
}
|
|
|
|
// Just allocate the required size for the given type assuming the
|
|
// type has a trivial constructor.
|
|
template <typename T>
|
|
PROTOBUF_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.";
|
|
const size_t n = internal::AlignUpTo8(sizeof(T) * num_elements);
|
|
// Monitor allocation if needed.
|
|
AllocHook(RTTI_TYPE_ID(T), n);
|
|
return static_cast<T*>(AllocateAlignedNoHook(n));
|
|
}
|
|
|
|
template <typename T, typename... Args>
|
|
PROTOBUF_ALWAYS_INLINE T* DoCreate(bool skip_explicit_ownership,
|
|
Args&&... args) {
|
|
return new (AllocateInternal<T>(skip_explicit_ownership))
|
|
T(std::forward<Args>(args)...);
|
|
}
|
|
template <typename T, typename... Args>
|
|
PROTOBUF_ALWAYS_INLINE T* DoCreateMessage(Args&&... args) {
|
|
return InternalHelper<T>::Construct(
|
|
AllocateInternal<T>(InternalHelper<T>::is_destructor_skippable::value),
|
|
this, std::forward<Args>(args)...);
|
|
}
|
|
|
|
// CreateInArenaStorage is used to implement map field. Without it,
|
|
// Map need to call generated message's protected arena constructor,
|
|
// which needs to declare Map as friend of generated message.
|
|
template <typename T, typename... Args>
|
|
static void CreateInArenaStorage(T* ptr, Arena* arena, Args&&... args) {
|
|
CreateInArenaStorageInternal(ptr, arena,
|
|
typename is_arena_constructable<T>::type(),
|
|
std::forward<Args>(args)...);
|
|
RegisterDestructorInternal(
|
|
ptr, arena,
|
|
typename InternalHelper<T>::is_destructor_skippable::type());
|
|
}
|
|
|
|
template <typename T, typename... Args>
|
|
static void CreateInArenaStorageInternal(T* ptr, Arena* arena,
|
|
std::true_type, Args&&... args) {
|
|
InternalHelper<T>::Construct(ptr, arena, std::forward<Args>(args)...);
|
|
}
|
|
template <typename T, typename... Args>
|
|
static void CreateInArenaStorageInternal(T* ptr, Arena* /* arena */,
|
|
std::false_type, Args&&... args) {
|
|
new (ptr) T(std::forward<Args>(args)...);
|
|
}
|
|
|
|
template <typename T>
|
|
static void RegisterDestructorInternal(T* /* ptr */, Arena* /* arena */,
|
|
std::true_type) {}
|
|
template <typename T>
|
|
static void RegisterDestructorInternal(T* ptr, Arena* arena,
|
|
std::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 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>
|
|
PROTOBUF_ALWAYS_INLINE void OwnInternal(T* object, std::true_type) {
|
|
if (object != NULL) {
|
|
impl_.AddCleanup(object, &internal::arena_delete_object<Message>);
|
|
}
|
|
}
|
|
template <typename T>
|
|
PROTOBUF_ALWAYS_INLINE void OwnInternal(T* object, std::false_type) {
|
|
if (object != NULL) {
|
|
impl_.AddCleanup(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 GetArena() method.
|
|
template <typename T, typename std::enable_if<
|
|
is_arena_constructable<T>::value, int>::type = 0>
|
|
PROTOBUF_ALWAYS_INLINE static Arena* GetArenaInternal(const T* value) {
|
|
return InternalHelper<T>::GetArena(value);
|
|
}
|
|
template <typename T,
|
|
typename std::enable_if<!is_arena_constructable<T>::value &&
|
|
has_get_arena<T>::value,
|
|
int>::type = 0>
|
|
PROTOBUF_ALWAYS_INLINE static Arena* GetArenaInternal(const T* value) {
|
|
return value->GetArena();
|
|
}
|
|
template <typename T,
|
|
typename std::enable_if<!is_arena_constructable<T>::value &&
|
|
!has_get_arena<T>::value,
|
|
int>::type = 0>
|
|
PROTOBUF_ALWAYS_INLINE static Arena* GetArenaInternal(const T* value) {
|
|
(void)value;
|
|
return nullptr;
|
|
}
|
|
|
|
// For friends of arena.
|
|
void* AllocateAligned(size_t n) {
|
|
AllocHook(NULL, n);
|
|
return AllocateAlignedNoHook(internal::AlignUpTo8(n));
|
|
}
|
|
template<size_t Align>
|
|
void* AllocateAlignedTo(size_t n) {
|
|
static_assert(Align > 0, "Alignment must be greater than 0");
|
|
static_assert((Align & (Align - 1)) == 0, "Alignment must be power of two");
|
|
if (Align <= 8) return AllocateAligned(n);
|
|
// TODO(b/151247138): if the pointer would have been aligned already,
|
|
// this is wasting space. We should pass the alignment down.
|
|
uintptr_t ptr = reinterpret_cast<uintptr_t>(AllocateAligned(n + Align - 8));
|
|
ptr = (ptr + Align - 1) & -Align;
|
|
return reinterpret_cast<void*>(ptr);
|
|
}
|
|
|
|
void* AllocateAlignedNoHook(size_t n);
|
|
|
|
internal::ArenaImpl impl_;
|
|
|
|
void (*on_arena_allocation_)(const std::type_info* allocated_type,
|
|
uint64 alloc_size, void* cookie);
|
|
void (*on_arena_reset_)(Arena* arena, void* cookie, uint64 space_used);
|
|
void (*on_arena_destruction_)(Arena* arena, void* cookie, uint64 space_used);
|
|
|
|
// 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_;
|
|
|
|
template <typename Type>
|
|
friend class internal::GenericTypeHandler;
|
|
friend struct internal::ArenaStringPtr; // For AllocateAligned.
|
|
friend class internal::LazyField; // For CreateMaybeMessage.
|
|
friend class internal::EpsCopyInputStream; // For parser performance
|
|
friend class MessageLite;
|
|
template <typename Key, typename T>
|
|
friend class Map;
|
|
};
|
|
|
|
// Defined above for supporting environments without RTTI.
|
|
#undef RTTI_TYPE_ID
|
|
|
|
} // namespace protobuf
|
|
} // namespace google
|
|
|
|
#include <google/protobuf/port_undef.inc>
|
|
|
|
#endif // GOOGLE_PROTOBUF_ARENA_H__
|