explicitly_constructed.h | Explore in Territory

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#ifndef GOOGLE_PROTOBUF_EXPLICITLY_CONSTRUCTED_H__
#define GOOGLE_PROTOBUF_EXPLICITLY_CONSTRUCTED_H__

#include <stdint.h>

#include <utility>

#include <google/protobuf/stubs/logging.h>
#include <google/protobuf/stubs/common.h>

// clang-format off
#include <google/protobuf/port_def.inc>
// clang-format on

namespace google {
namespace protobuf {
namespace internal {

// Wraps a variable whose constructor and destructor are explicitly
// called. It is particularly useful for a global variable, without its
// constructor and destructor run on start and end of the program lifetime.
// This circumvents the initial construction order fiasco, while keeping
// the address of the empty string a compile time constant.
//
// Pay special attention to the initialization state of the object.
// 1. The object is "uninitialized" to begin with.
// 2. Call Construct() or DefaultConstruct() only if the object is
//    uninitialized. After the call, the object becomes "initialized".
// 3. Call get() and get_mutable() only if the object is initialized.
// 4. Call Destruct() only if the object is initialized.
//    After the call, the object becomes uninitialized.
template <typename T, size_t min_align = 1>
class ExplicitlyConstructed { … };

// ArenaStringPtr compatible explicitly constructed string type.
// This empty string type is aligned with a minimum alignment of 8 bytes
// which is the minimum requirement of ArenaStringPtr
ExplicitlyConstructedArenaString;

}  // namespace internal
}  // namespace protobuf
}  // namespace google

#include <google/protobuf/port_undef.inc>

#endif  // GOOGLE_PROTOBUF_EXPLICITLY_CONSTRUCTED_H__
chromium/third_party/protobuf/src/google/protobuf/explicitly_constructed.h
