poll_io_controller.h

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// Copyright (c) 2018, Smart Projects Holdings Ltd
// All rights reserved.
// See LICENSE file for license details.

#ifndef _UGCS_VSM_POLL_IO_CONTROLLER_H_
#define _UGCS_VSM_POLL_IO_CONTROLLER_H_

#include <ugcs/vsm/file_processor.h>
#include <poll.h>
#include <fcntl.h>
#include <unistd.h>

namespace ugcs {
namespace vsm {
namespace internal {

class Poll_io_controller: public File_processor::Native_controller {
public:

    struct Io_cb {
        // @{
        enum class Operation {
            READ,
            WRITE
        };
        // @}

        typedef void (*Callback)(Io_cb &);

        int fd;
        Operation op;
        void *buf;
        size_t size;
        Io_stream::Offset offset;
        Callback cbk;

        int error;
        ssize_t return_value;
    };

    Poll_io_controller();

    virtual
    ~Poll_io_controller();

    virtual void
    Enable() override;

    virtual void
    Disable() override;

    virtual void
    Register_handle(File_processor::Stream::Native_handle &) override
    {}

    virtual void
    Unregister_handle(File_processor::Stream::Native_handle &) override
    {}

    void
    Delete_handle(int fd);

    bool
    Queue_operation(Io_cb &io_cb);

    bool
    Cancel_operation(Io_cb &io_cb);

private:
    class File_desc {
    public:
        Io_cb *read_cb = nullptr,
              *write_cb = nullptr;
        size_t poll_fd_idx = 0;
        bool close_on_remove = false;
    };
    std::thread dispatcher_thread;
    std::atomic_bool quit_req = { false };
    std::map<int, File_desc> fd_map;
    std::mutex map_mutex;
    std::vector<pollfd> poll_fd_array;
    int signal_fd;

    void
    Dispatcher_thread();

    void
    Read(Io_cb &io_cb);

    void
    Write(Io_cb &io_cb);

    void
    Seek(Io_cb &io_cb);

    size_t
    Allocate_poll_fd_index();

    void
    Release_poll_fd_index(size_t idx);

    void
    Send_signal();

    void
    Accept_signal();

    void
    Update_poll_fd_array();
};

} /* namespace internal */
} /* namespace vsm */
} /* namespace ugcs */

#endif /* _UGCS_VSM_POLL_IO_CONTROLLER_H_ */