aio.cpp

Demonstrats use of aio readers/writersAccepts to filenames. Copies contents of first file into second file, calculatung file hash in the process.

#include <libfilezilla/aio/reader.hpp>
#include <libfilezilla/aio/writer.hpp>
#include <libfilezilla/logger.hpp>
 
#include <libfilezilla/encode.hpp>
#include <libfilezilla/event_handler.hpp>
#include <libfilezilla/event_loop.hpp>
#include <libfilezilla/hash.hpp>
 
#include <atomic>
 
class worker : public fz::event_handler
{
public:
    worker(fz::logger_interface & logger, fz::event_loop & loop, std::unique_ptr<fz::reader_factory> && in_factory, std::unique_ptr<fz::writer_factory> && out_factory)
        : fz::event_handler(loop)
        , logger_(logger)
        , reader_factory_(in_factory)
        , writer_factory_(out_factory)
    {
        if (!buffer_pool_) {
            logger_.log(fz::logmsg::error, "Could not init buffer pool");
            loop.stop();
            return;
        }
 
        reader_ = reader_factory_->open(buffer_pool_);
        if (!reader_) {
            logger_.log(fz::logmsg::error, "Could not open %s", reader_factory_->name());
            loop.stop();
            return;
        }
 
        auto cb = [this](fz::writer_base const*, uint64_t written) {
            written_ += written;
        };
        writer_ = writer_factory_->open(buffer_pool_, 0, cb);
        if (!writer_) {
            logger_.log(fz::logmsg::error, "Could not open %s", writer_factory_->name());
            loop.stop();
            return;
        }
    }
 
    virtual ~worker() {
        remove_handler();
 
        if (success_) {
            logger_.log(fz::logmsg::status, "File copied successfully, wrote %d bytes", written_.load());
            logger_.log(fz::logmsg::status, "Hash of data copied is %s", fz::hex_encode<std::string>(hash_.digest()));
        }
        else {
            logger_.log(fz::logmsg::error, "Copy failed.");
        }
    }
 
    virtual void operator()(fz::event_base const&) override
    {
        for (size_t i = 0; i < 10; ++i) {
            auto [res, b] = reader_->get_buffer(*this);
            if (res == fz::aio_result::error) {
                event_loop_.stop();
                return;
            }
            if (res != fz::aio_result::ok) {
                return;
            }
            if (!b) {
                auto res = writer_->finalize(*this);
                if (res == fz::aio_result::wait) {
                    return;
                }
                else if (res == fz::aio_result::error) {
                    event_loop_.stop();
                    return;
                }
 
                success_ = true;
                event_loop_.stop();
                return;
            }
 
            hash_.update(b->get(), b->size());
            done_ += b->size();
 
            res = writer_->add_buffer(std::move(b), *this);
            if (res == fz::aio_result::wait) {
                return;
            }
            else if (res == fz::aio_result::error) {
                event_loop_.stop();
                return;
            }
        }
        send_event<fz::aio_buffer_event>(nullptr);
    }
 
    fz::logger_interface & logger_;
 
    fz::reader_factory_holder reader_factory_;
    fz::writer_factory_holder writer_factory_;
 
    uint64_t done_{};
    fz::hash_accumulator hash_{fz::hash_algorithm::sha1};
    fz::aio_buffer_pool buffer_pool_{logger_, 8};
    std::unique_ptr<fz::reader_base> reader_;
    std::unique_ptr<fz::writer_base> writer_;
 
    std::atomic<uint64_t> written_{};
    bool success_{};
};
 
int main(int argc, char* argv[])
{
    fz::stdout_logger logger;
 
    if (argc != 3) {
        logger.log(fz::logmsg::error, "Pass input and output filename");
        return 1;
    }
 
    fz::thread_pool pool;
 
    auto in = std::make_unique<fz::file_reader_factory>(fz::to_wstring(argv[1]), pool);
    auto out = std::make_unique<fz::file_writer_factory>(fz::to_wstring(argv[2]), pool);
 
    fz::event_loop loop(fz::event_loop::threadless);
 
    worker w(logger, loop, std::move(in), std::move(out));
    w.send_event<fz::aio_buffer_event>(nullptr);
 
    loop.run();
 
    return 0;
}