// // Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2019 // // Distributed under the Boost Software License, Version 1.0. (See accompanying // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // #pragma once #include "td/utils/buffer.h" #include "td/utils/common.h" #include "td/utils/format.h" #include "td/utils/logging.h" #include "td/utils/port/detail/PollableFd.h" #include "td/utils/Slice.h" #include "td/utils/Status.h" #include <limits> namespace td { // just reads from given reader and writes to given writer template <class FdT> class BufferedFdBase : public FdT { public: BufferedFdBase() = default; explicit BufferedFdBase(FdT &&fd_); // TODO: make move constructor and move assignment safer Result<size_t> flush_read(size_t max_read = std::numeric_limits<size_t>::max()) TD_WARN_UNUSED_RESULT; Result<size_t> flush_write() TD_WARN_UNUSED_RESULT; bool need_flush_write(size_t at_least = 0) { CHECK(write_); write_->sync_with_writer(); return write_->size() > at_least; } size_t ready_for_flush_write() { CHECK(write_); write_->sync_with_writer(); return write_->size(); } void set_input_writer(ChainBufferWriter *read) { read_ = read; } void set_output_reader(ChainBufferReader *write) { write_ = write; } private: ChainBufferWriter *read_ = nullptr; ChainBufferReader *write_ = nullptr; }; template <class FdT> class BufferedFd : public BufferedFdBase<FdT> { using Parent = BufferedFdBase<FdT>; ChainBufferWriter input_writer_; ChainBufferReader input_reader_; ChainBufferWriter output_writer_; ChainBufferReader output_reader_; void init(); void init_ptr(); public: BufferedFd(); explicit BufferedFd(FdT &&fd_); BufferedFd(BufferedFd &&); BufferedFd &operator=(BufferedFd &&); BufferedFd(const BufferedFd &) = delete; BufferedFd &operator=(const BufferedFd &) = delete; ~BufferedFd(); void close(); Result<size_t> flush_read(size_t max_read = std::numeric_limits<size_t>::max()) TD_WARN_UNUSED_RESULT; Result<size_t> flush_write() TD_WARN_UNUSED_RESULT; // Yep, direct access to buffers. It is IO interface too. ChainBufferReader &input_buffer(); ChainBufferWriter &output_buffer(); }; // IMPLEMENTATION /*** BufferedFd ***/ template <class FdT> BufferedFdBase<FdT>::BufferedFdBase(FdT &&fd_) : FdT(std::move(fd_)) { } template <class FdT> Result<size_t> BufferedFdBase<FdT>::flush_read(size_t max_read) { CHECK(read_); size_t result = 0; while (::td::can_read(*this) && max_read) { MutableSlice slice = read_->prepare_append().truncate(max_read); TRY_RESULT(x, FdT::read(slice)); slice.truncate(x); read_->confirm_append(x); result += x; max_read -= x; } return result; } template <class FdT> Result<size_t> BufferedFdBase<FdT>::flush_write() { size_t result = 0; // TODO: sync on demand write_->sync_with_writer(); while (!write_->empty() && ::td::can_write(*this)) { Slice slice = write_->prepare_read(); TRY_RESULT(x, FdT::write(slice)); write_->confirm_read(x); result += x; } return result; } /*** BufferedFd ***/ template <class FdT> void BufferedFd<FdT>::init() { input_reader_ = input_writer_.extract_reader(); output_reader_ = output_writer_.extract_reader(); init_ptr(); } template <class FdT> void BufferedFd<FdT>::init_ptr() { this->set_input_writer(&input_writer_); this->set_output_reader(&output_reader_); } template <class FdT> BufferedFd<FdT>::BufferedFd() { init(); } template <class FdT> BufferedFd<FdT>::BufferedFd(FdT &&fd_) : Parent(std::move(fd_)) { init(); } template <class FdT> BufferedFd<FdT>::BufferedFd(BufferedFd &&from) { *this = std::move(from); } template <class FdT> BufferedFd<FdT> &BufferedFd<FdT>::operator=(BufferedFd &&from) { FdT::operator=(std::move(static_cast<FdT &>(from))); input_reader_ = std::move(from.input_reader_); input_writer_ = std::move(from.input_writer_); output_reader_ = std::move(from.output_reader_); output_writer_ = std::move(from.output_writer_); init_ptr(); return *this; } template <class FdT> BufferedFd<FdT>::~BufferedFd() { close(); } template <class FdT> void BufferedFd<FdT>::close() { FdT::close(); // TODO: clear buffers } template <class FdT> Result<size_t> BufferedFd<FdT>::flush_read(size_t max_read) { TRY_RESULT(result, Parent::flush_read(max_read)); if (result) { // TODO: faster sync is possible if you owns writer. input_reader_.sync_with_writer(); LOG(DEBUG) << "Flush read: +" << format::as_size(result) << tag("total", format::as_size(input_reader_.size())); } return result; } template <class FdT> Result<size_t> BufferedFd<FdT>::flush_write() { TRY_RESULT(result, Parent::flush_write()); if (result) { LOG(DEBUG) << "Flush write: +" << format::as_size(result) << tag("left", format::as_size(output_reader_.size())); } return result; } // Yep, direct access to buffers. It is IO interface too. template <class FdT> ChainBufferReader &BufferedFd<FdT>::input_buffer() { return input_reader_; } template <class FdT> ChainBufferWriter &BufferedFd<FdT>::output_buffer() { return output_writer_; } } // namespace td