73 lines
2.3 KiB
C++
73 lines
2.3 KiB
C++
#pragma once
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#include <cstddef>
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#include <memory>
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#include <sys/mman.h>
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#include <sys/resource.h>
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struct Connection;
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/**
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* mmap-based Connection Registry for tracking active connections.
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*
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* This registry provides a lock-free mechanism for tracking all connections
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* owned by the server, indexed by file descriptor. The design uses mmap to
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* allocate a large virtual address space efficiently, with physical memory
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* allocated on-demand as connections are created.
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*
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*/
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class ConnectionRegistry {
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public:
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/**
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* Initialize the connection registry.
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* Allocates virtual address space based on RLIMIT_NOFILE.
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*
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* @throws std::runtime_error if mmap fails or RLIMIT_NOFILE cannot be read
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*/
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ConnectionRegistry();
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/**
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* Destructor ensures proper cleanup of mmap'd memory.
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*/
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~ConnectionRegistry();
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/**
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* Store a connection in the registry, indexed by its file descriptor.
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* Takes ownership of the connection via unique_ptr.
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*
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* @param fd File descriptor (must be valid and < max_fds_)
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* @param connection unique_ptr to the connection (ownership transferred)
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*/
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void store(int fd, std::unique_ptr<Connection> connection);
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/**
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* Remove a connection from the registry and transfer ownership to caller.
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* This transfers ownership via unique_ptr move semantics.
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*
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* @param fd File descriptor
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* @return unique_ptr to the connection, or nullptr if not found
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*/
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std::unique_ptr<Connection> remove(int fd);
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/**
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* Get the maximum number of file descriptors supported.
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*
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* @return Maximum file descriptor limit
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*/
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size_t max_fds() const { return max_fds_; }
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// Non-copyable and non-movable
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ConnectionRegistry(const ConnectionRegistry &) = delete;
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ConnectionRegistry &operator=(const ConnectionRegistry &) = delete;
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ConnectionRegistry(ConnectionRegistry &&) = delete;
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ConnectionRegistry &operator=(ConnectionRegistry &&) = delete;
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private:
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std::atomic<Connection *>
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*connections_; ///< mmap'd array of raw connection pointers. It's
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///< thread-safe without since epoll_ctl happens before
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///< epoll_wait, but this makes tsan happy /shrug.
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size_t max_fds_; ///< Maximum file descriptor limit
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size_t aligned_size_; ///< Page-aligned size for munmap
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};
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