mirror of
https://gitee.com/acl-dev/acl.git
synced 2024-12-14 17:00:52 +08:00
9697f95b8f
This reverts commit 15d999759e
.
167 lines
6.1 KiB
C++
167 lines
6.1 KiB
C++
// Protocol Buffers - Google's data interchange format
|
|
// Copyright 2008 Google Inc. All rights reserved.
|
|
// http://code.google.com/p/protobuf/
|
|
//
|
|
// 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.
|
|
|
|
// Author: kenton@google.com (Kenton Varda)
|
|
//
|
|
// emulates google3/base/once.h
|
|
//
|
|
// This header is intended to be included only by internal .cc files and
|
|
// generated .pb.cc files. Users should not use this directly.
|
|
//
|
|
// This is basically a portable version of pthread_once().
|
|
//
|
|
// This header declares:
|
|
// * A type called ProtobufOnceType.
|
|
// * A macro GOOGLE_PROTOBUF_DECLARE_ONCE() which declares a variable of type
|
|
// ProtobufOnceType. This is the only legal way to declare such a variable.
|
|
// The macro may only be used at the global scope (you cannot create local or
|
|
// class member variables of this type).
|
|
// * A function GoogleOnceInit(ProtobufOnceType* once, void (*init_func)()).
|
|
// This function, when invoked multiple times given the same ProtobufOnceType
|
|
// object, will invoke init_func on the first call only, and will make sure
|
|
// none of the calls return before that first call to init_func has finished.
|
|
// * The user can provide a parameter which GoogleOnceInit() forwards to the
|
|
// user-provided function when it is called. Usage example:
|
|
// int a = 10;
|
|
// GoogleOnceInit(&my_once, &MyFunctionExpectingIntArgument, &a);
|
|
// * This implementation guarantees that ProtobufOnceType is a POD (i.e. no
|
|
// static initializer generated).
|
|
//
|
|
// This implements a way to perform lazy initialization. It's more efficient
|
|
// than using mutexes as no lock is needed if initialization has already
|
|
// happened.
|
|
//
|
|
// Example usage:
|
|
// void Init();
|
|
// GOOGLE_PROTOBUF_DECLARE_ONCE(once_init);
|
|
//
|
|
// // Calls Init() exactly once.
|
|
// void InitOnce() {
|
|
// GoogleOnceInit(&once_init, &Init);
|
|
// }
|
|
//
|
|
// Note that if GoogleOnceInit() is called before main() has begun, it must
|
|
// only be called by the thread that will eventually call main() -- that is,
|
|
// the thread that performs dynamic initialization. In general this is a safe
|
|
// assumption since people don't usually construct threads before main() starts,
|
|
// but it is technically not guaranteed. Unfortunately, Win32 provides no way
|
|
// whatsoever to statically-initialize its synchronization primitives, so our
|
|
// only choice is to assume that dynamic initialization is single-threaded.
|
|
|
|
#ifndef GOOGLE_PROTOBUF_STUBS_ONCE_H__
|
|
#define GOOGLE_PROTOBUF_STUBS_ONCE_H__
|
|
|
|
#include <google/protobuf/stubs/atomicops.h>
|
|
#include <google/protobuf/stubs/common.h>
|
|
|
|
namespace google {
|
|
namespace protobuf {
|
|
|
|
#ifdef GOOGLE_PROTOBUF_NO_THREAD_SAFETY
|
|
|
|
typedef bool ProtobufOnceType;
|
|
|
|
#define GOOGLE_PROTOBUF_ONCE_INIT false
|
|
|
|
inline void GoogleOnceInit(ProtobufOnceType* once, void (*init_func)()) {
|
|
if (!*once) {
|
|
*once = true;
|
|
init_func();
|
|
}
|
|
}
|
|
|
|
template <typename Arg>
|
|
inline void GoogleOnceInit(ProtobufOnceType* once, void (*init_func)(Arg),
|
|
Arg arg) {
|
|
if (!*once) {
|
|
*once = true;
|
|
init_func(arg);
|
|
}
|
|
}
|
|
|
|
#else
|
|
|
|
enum {
|
|
ONCE_STATE_UNINITIALIZED = 0,
|
|
ONCE_STATE_EXECUTING_CLOSURE = 1,
|
|
ONCE_STATE_DONE = 2
|
|
};
|
|
|
|
typedef internal::AtomicWord ProtobufOnceType;
|
|
|
|
#define GOOGLE_PROTOBUF_ONCE_INIT ::google::protobuf::ONCE_STATE_UNINITIALIZED
|
|
|
|
LIBPROTOBUF_EXPORT
|
|
void GoogleOnceInitImpl(ProtobufOnceType* once, Closure* closure);
|
|
|
|
inline void GoogleOnceInit(ProtobufOnceType* once, void (*init_func)()) {
|
|
if (internal::Acquire_Load(once) != ONCE_STATE_DONE) {
|
|
internal::FunctionClosure0 func(init_func, false);
|
|
GoogleOnceInitImpl(once, &func);
|
|
}
|
|
}
|
|
|
|
template <typename Arg>
|
|
inline void GoogleOnceInit(ProtobufOnceType* once, void (*init_func)(Arg*),
|
|
Arg* arg) {
|
|
if (internal::Acquire_Load(once) != ONCE_STATE_DONE) {
|
|
internal::FunctionClosure1<Arg*> func(init_func, false, arg);
|
|
GoogleOnceInitImpl(once, &func);
|
|
}
|
|
}
|
|
|
|
#endif // GOOGLE_PROTOBUF_NO_THREAD_SAFETY
|
|
|
|
class GoogleOnceDynamic {
|
|
public:
|
|
GoogleOnceDynamic() : state_(GOOGLE_PROTOBUF_ONCE_INIT) { }
|
|
|
|
// If this->Init() has not been called before by any thread,
|
|
// execute (*func_with_arg)(arg) then return.
|
|
// Otherwise, wait until that prior invocation has finished
|
|
// executing its function, then return.
|
|
template<typename T>
|
|
void Init(void (*func_with_arg)(T*), T* arg) {
|
|
GoogleOnceInit<T>(&this->state_,
|
|
func_with_arg,
|
|
arg);
|
|
}
|
|
private:
|
|
ProtobufOnceType state_;
|
|
};
|
|
|
|
#define GOOGLE_PROTOBUF_DECLARE_ONCE(NAME) \
|
|
::google::protobuf::ProtobufOnceType NAME = GOOGLE_PROTOBUF_ONCE_INIT
|
|
|
|
} // namespace protobuf
|
|
} // namespace google
|
|
|
|
#endif // GOOGLE_PROTOBUF_STUBS_ONCE_H__
|