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86 lines
2.7 KiB
C++
Executable File
86 lines
2.7 KiB
C++
Executable File
#pragma once
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#include <cstddef>
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#include <cstdint>
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#include "libipc/imp/export.h"
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namespace ipc {
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namespace shm {
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using id_t = void*;
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enum : unsigned {
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create = 0x01,
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open = 0x02
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};
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IPC_EXPORT id_t acquire(char const * name, std::size_t size, unsigned mode = create | open);
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IPC_EXPORT void * get_mem(id_t id, std::size_t * size);
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// Release shared memory resource and clean up disk file if reference count reaches zero.
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// This function decrements the reference counter. When the counter reaches zero, it:
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// 1. Unmaps the shared memory region
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// 2. Removes the backing file from disk (shm_unlink on POSIX)
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// 3. Frees the id structure
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// After calling this function, the id becomes invalid and must not be used again.
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// Returns: The reference count before decrement, or -1 on error.
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IPC_EXPORT std::int32_t release(id_t id) noexcept;
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// Release shared memory resource and force cleanup of disk file.
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// This function calls release(id) internally, then unconditionally attempts to
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// remove the backing file. WARNING: Do NOT call this after release(id) on the
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// same id, as the id is already freed by release(). Use this function alone,
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// not in combination with release().
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// Typical use case: Force cleanup when you want to ensure the disk file is removed
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// regardless of reference count state.
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IPC_EXPORT void remove (id_t id) noexcept;
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// Remove shared memory backing file by name.
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// This function only removes the disk file and does not affect any active memory
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// mappings or id structures. Use this for cleanup of orphaned files or for explicit
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// file removal without affecting runtime resources.
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// Safe to call at any time, even if shared memory is still in use elsewhere.
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IPC_EXPORT void remove (char const * name) noexcept;
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IPC_EXPORT std::int32_t get_ref(id_t id);
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IPC_EXPORT void sub_ref(id_t id);
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class IPC_EXPORT handle {
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public:
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handle();
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handle(char const * name, std::size_t size, unsigned mode = create | open);
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handle(handle&& rhs);
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~handle();
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void swap(handle& rhs);
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handle& operator=(handle rhs);
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bool valid() const noexcept;
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std::size_t size () const noexcept;
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char const * name () const noexcept;
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std::int32_t ref() const noexcept;
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void sub_ref() noexcept;
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bool acquire(char const * name, std::size_t size, unsigned mode = create | open);
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std::int32_t release();
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// Clean the handle file.
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void clear() noexcept;
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static void clear_storage(char const * name) noexcept;
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void* get() const;
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void attach(id_t);
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id_t detach();
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private:
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class handle_;
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handle_* p_;
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};
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} // namespace shm
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} // namespace ipc
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