initial commit

tdutils/td/utils/port/detail/Select.cpp

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+/*
+    This file is part of TON Blockchain Library.
+
+    TON Blockchain Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    TON Blockchain Library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.
+
+    Copyright 2017-2019 Telegram Systems LLP
+*/
+#include "td/utils/port/detail/Select.h"
+
+char disable_linker_warning_about_empty_file_select_cpp TD_UNUSED;
+
+#ifdef TD_POLL_SELECT
+
+#include "td/utils/logging.h"
+
+#include <utility>
+
+namespace td {
+namespace detail {
+
+void Select::init() {
+  FD_ZERO(&all_fd_);
+  FD_ZERO(&read_fd_);
+  FD_ZERO(&write_fd_);
+  FD_ZERO(&except_fd_);
+  max_fd_ = -1;
+}
+
+void Select::clear() {
+  fds_.clear();
+}
+
+void Select::subscribe(PollableFd fd, PollFlags flags) {
+  int native_fd = fd.native_fd().fd();
+  for (auto &it : fds_) {
+    CHECK(it.fd.native_fd().fd() != native_fd);
+  }
+  fds_.push_back(FdInfo{std::move(fd), flags});
+  LOG_CHECK(0 <= native_fd && native_fd < FD_SETSIZE) << native_fd << " " << FD_SETSIZE;
+  FD_SET(native_fd, &all_fd_);
+  if (native_fd > max_fd_) {
+    max_fd_ = native_fd;
+  }
+}
+
+void Select::unsubscribe(PollableFdRef fd) {
+  auto fd_locked = fd.lock();
+  int native_fd = fd_locked.native_fd().fd();
+  fd_locked.release_as_list_node();
+
+  LOG_CHECK(0 <= native_fd && native_fd < FD_SETSIZE) << native_fd << " " << FD_SETSIZE;
+  FD_CLR(native_fd, &all_fd_);
+  FD_CLR(native_fd, &read_fd_);
+  FD_CLR(native_fd, &write_fd_);
+  FD_CLR(native_fd, &except_fd_);
+  while (max_fd_ >= 0 && !FD_ISSET(max_fd_, &all_fd_)) {
+    max_fd_--;
+  }
+  for (auto it = fds_.begin(); it != fds_.end();) {
+    if (it->fd.native_fd().fd() == native_fd) {
+      std::swap(*it, fds_.back());
+      fds_.pop_back();
+      break;
+    } else {
+      ++it;
+    }
+  }
+}
+
+void Select::unsubscribe_before_close(PollableFdRef fd) {
+  unsubscribe(fd);
+}
+
+void Select::run(int timeout_ms) {
+  timeval timeout_data;
+  timeval *timeout_ptr;
+  if (timeout_ms == -1) {
+    timeout_ptr = nullptr;
+  } else {
+    timeout_data.tv_sec = timeout_ms / 1000;
+    timeout_data.tv_usec = timeout_ms % 1000 * 1000;
+    timeout_ptr = &timeout_data;
+  }
+
+  for (auto &it : fds_) {
+    int native_fd = it.fd.native_fd().fd();
+    PollFlags fd_flags = it.fd.get_flags_unsafe();  // concurrent calls are UB
+    if (it.flags.can_write() && !fd_flags.can_write()) {
+      FD_SET(native_fd, &write_fd_);
+    } else {
+      FD_CLR(native_fd, &write_fd_);
+    }
+    if (it.flags.can_read() && !fd_flags.can_read()) {
+      FD_SET(native_fd, &read_fd_);
+    } else {
+      FD_CLR(native_fd, &read_fd_);
+    }
+    FD_SET(native_fd, &except_fd_);
+  }
+
+  select(max_fd_ + 1, &read_fd_, &write_fd_, &except_fd_, timeout_ptr);
+  for (auto &it : fds_) {
+    int native_fd = it.fd.native_fd().fd();
+    PollFlags flags;
+    if (FD_ISSET(native_fd, &read_fd_)) {
+      flags = flags | PollFlags::Read();
+    }
+    if (FD_ISSET(native_fd, &write_fd_)) {
+      flags = flags | PollFlags::Write();
+    }
+    if (FD_ISSET(native_fd, &except_fd_)) {
+      flags = flags | PollFlags::Error();
+    }
+    it.fd.add_flags(flags);
+  }
+}
+
+}  // namespace detail
+}  // namespace td
+
+#endif