92 lines
2.3 KiB
C++
92 lines
2.3 KiB
C++
/**
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* Copyright (c) 2017 by Contributors
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* @file dgl/runtime/ndarray.h
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* @brief shared memory management.
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*/
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#ifndef DGL_RUNTIME_SHARED_MEM_H_
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#define DGL_RUNTIME_SHARED_MEM_H_
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#ifdef _WIN32
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#include <windows.h>
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#endif // _WIN32
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#include <string>
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namespace dgl {
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namespace runtime {
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/**
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* @brief This class owns shared memory.
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*
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* When the object is gone, the shared memory will also be destroyed.
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* When the shared memory is destroyed, the file corresponding to
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* the shared memory is removed.
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*/
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class SharedMemory {
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/**
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* @brief whether the shared memory is owned by the object.
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*
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* If shared memory is created in the object, it'll be owned by the object
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* and will be responsible for deleting it when the object is destroyed.
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*/
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bool own_;
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/* @brief the file descripter of the shared memory. */
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#ifndef _WIN32
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int fd_;
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#else // !_WIN32
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HANDLE handle_;
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#endif // _WIN32
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/* @brief the address of the shared memory. */
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void *ptr_;
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/* @brief the size of the shared memory. */
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size_t size_;
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/**
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* @brief the name of the object.
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*
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* In Unix, shared memory is identified by a file. Thus, `name` is actually
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* the file name that identifies the shared memory.
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*/
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std::string name;
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public:
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/* @brief Get the filename of shared memory file
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*/
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std::string GetName() const { return name; }
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/**
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* @brief constructor of the shared memory.
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* @param name The file corresponding to the shared memory.
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*/
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explicit SharedMemory(const std::string &name);
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/**
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* @brief destructor of the shared memory.
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* It deallocates the shared memory and removes the corresponding file.
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*/
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~SharedMemory();
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/**
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* @brief create shared memory.
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* It creates the file and shared memory.
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* @param sz the size of the shared memory.
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* @return the address of the shared memory
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*/
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void *CreateNew(size_t sz);
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/**
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* @brief allocate shared memory that has been created.
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* @param sz the size of the shared memory.
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* @return the address of the shared memory
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*/
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void *Open(size_t sz);
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/**
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* @brief check if the shared memory exist.
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* @param name the name of the shared memory.
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* @return a boolean value to indicate if the shared memory exists.
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*/
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static bool Exist(const std::string &name);
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};
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} // namespace runtime
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} // namespace dgl
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#endif // DGL_RUNTIME_SHARED_MEM_H_
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