/*
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* =====================================================================================
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*
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* Filename: shm.h
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*
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* Description:
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*
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* Version: 1.0
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* Created: 2021年03月22日 16时19分21秒
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* Revision: none
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* Compiler: gcc
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*
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* Author: Li Chao (),
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* Organization:
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*
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* =====================================================================================
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*/
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#ifndef SHM_6CHO6D6C
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#define SHM_6CHO6D6C
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#include <boost/interprocess/managed_shared_memory.hpp>
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#include <boost/interprocess/sync/interprocess_mutex.hpp>
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#include <boost/noncopyable.hpp>
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#include <string>
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namespace bhome_shm
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{
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using namespace boost::interprocess;
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typedef managed_shared_memory mshm_t;
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typedef interprocess_mutex Mutex;
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typedef scoped_lock<Mutex> Guard;
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class SharedMemory : public mshm_t
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{
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std::string name_;
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Mutex *pmutex_ = 0;
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static permissions AllowAll()
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{
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permissions perm;
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perm.set_unrestricted();
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return perm;
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}
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void Swap(SharedMemory &a);
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public:
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static bool Remove(const std::string &name) { return shared_memory_object::remove(name.c_str()); }
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SharedMemory(const std::string &name, const uint64_t size);
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~SharedMemory();
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std::string name() const { return name_; }
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bool Remove() { return Remove(name()); }
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template <class T, class... Params>
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T *FindOrCreate(const std::string &name, Params &&...params)
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{
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return find_or_construct<T>(name.c_str(), std::nothrow)(std::forward<decltype(params)>(params)...);
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}
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template <class T, class... Params>
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T *Create(const std::string &name, Params &&...params)
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{
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return construct<T>(name.c_str(), std::nothrow)(std::forward<decltype(params)>(params)...);
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}
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template <class T>
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bool Destroy(const std::string &name) { return destroy<T>(name.c_str()); }
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void *Alloc(const size_t size)
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{
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Guard lock(*pmutex_);
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return allocate(size, std::nothrow);
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}
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void Dealloc(void *p)
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{
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Guard lock(*pmutex_);
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if (p) { deallocate(p); }
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}
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template <class T>
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T *Find(const std::string &name) { return find<T>(name.c_str()).first; }
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};
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enum Mode {
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eOpen = 0,
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eCreate = 1,
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eOpenOrCreate = 2
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};
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// NamedShmObject manages an object in shared memory, but NamedShmObject itself is not in shared memory.
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template <class T>
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class NamedShmObject : private boost::noncopyable
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{
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static std::string ObjName(const std::string &name) { return "obj" + name; }
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public:
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typedef T Data;
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typedef SharedMemory ShmType;
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ShmType &shm() const { return shm_; }
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template <class... Params>
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NamedShmObject(ShmType &segment, const std::string &name, Mode mode, Params &&...t) :
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shm_(segment), name_(name)
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{
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switch (mode) {
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case eOpen:
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pdata_ = shm_.Find<Data>(ObjName(name_));
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break;
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case eCreate:
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pdata_ = shm_.Create<Data>(ObjName(name_), std::forward<decltype(t)>(t)...);
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break;
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case eOpenOrCreate:
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pdata_ = shm_.FindOrCreate<Data>(ObjName(name_), std::forward<decltype(t)>(t)...);
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break;
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default: break;
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}
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if (!IsOk()) {
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throw std::runtime_error("Error: shm can not create/open \"" + name_ + "\"");
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}
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}
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NamedShmObject(const int64_t offset, ShmType &segment, const std::string &name) :
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shm_(segment), name_(name)
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{
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pdata_ = reinterpret_cast<Data *>(Addr(shm_.get_address()) + offset);
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}
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bool IsOk() const { return pdata_; }
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static bool Remove(SharedMemory &shm, const std::string &name) { return shm.Destroy<Data>(ObjName(name)); }
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static Data *Find(SharedMemory &shm, const std::string &name) { return shm.Find<Data>(ObjName(name)); }
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Data *Find(const std::string &name) { return Find(shm_, ObjName(name)); }
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virtual ~NamedShmObject() {}
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std::string name() const { return name_; }
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Data *data() { return pdata_; }
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const Data *data() const { return pdata_; }
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int64_t offset() const { return Addr(pdata_) - Addr(shm_.get_address()); }
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Data *operator->() { return data(); }
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const Data *operator->() const { return data(); }
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bool Remove() { return Remove(shm_, name_); }
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private:
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static int64_t Addr(const void *p) { return reinterpret_cast<int64_t>(p); }
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ShmType &shm_;
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std::string name_;
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Data *pdata_ = nullptr;
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};
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} // namespace bhome_shm
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#endif // end of include guard: SHM_6CHO6D6C
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