Move experimental async io to folly/io/async

Summary:
The following targets were moved to folly/io/async:
```
//folly/experimental/io:async_base
//folly/experimental/io:async_io
//folly/experimental/io:liburing
//folly/experimental/io:async_io_uring_socket
//folly/experimental/io:simple_async_io
//folly/experimental/io:epoll
//folly/experimental/io:epoll_backend
//folly/experimental/io:event_base_poller
//folly/experimental/io:mux_io_thread_pool_executor
//folly/experimental/io:io_uring
//folly/experimental/io:io_uring_backend
//folly/experimental/io:io_uring_provided_buffer_ring
//folly/experimental/io:io_uring_event
//folly/experimental/io:io_uring_event_base_local
//folly/experimental/io/test:async_io_test
//folly/experimental/io/test:async_io_uring_socket_test
//folly/experimental/io/test:epoll_backend_test
//folly/experimental/io/test:io_benchmark
//folly/experimental/io/test:io_uring_backend_bench
//folly/experimental/io/test:io_uring_backend_setup_test
//folly/experimental/io/test:io_uring_backend_test
//folly/experimental/io/test:io_uring_event_base_local_test
//folly/experimental/io/test:io_uring_event_test
//folly/experimental/io/test:io_uring_test
//folly/experimental/io/test:registered_fd_benchmark
//folly/experimental/io/test:simple_async_io_test
```

`arc f` was applied

This is a codemod. It was automatically generated and will be landed once it is approved and tests are passing in sandcastle.
You have been added as a reviewer by Sentinel or Butterfly.

p:meaio3.folly

Differential Revision: D59603836

fbshipit-source-id: 793e3a30ae5e27dfeda85d83ec7e11497cbb13d9

CMakeLists.txt

@@ -1141,12 +1141,12 @@ if (BUILD_TESTS OR BUILD_BENCHMARKS)
 
   if (${LIBAIO_FOUND})
     folly_define_tests(
-      DIRECTORY experimental/io/test/
+      DIRECTORY io/async/test/
         TEST async_io_test
           SOURCES
             AsyncIOTest.cpp
-            AsyncBaseTestLib.cpp
-            IoTestTempFileUtil.cpp
+            ../../../experimental/io/test/AsyncBaseTestLib.cpp
+            ../../../experimental/io/test/IoTestTempFileUtil.cpp
     )
   endif()
 

folly/experimental/io/AsyncBase.h

@@ -14,305 +14,4 @@
  * limitations under the License.
  */
 
-#pragma once
-
-#include <sys/types.h>
-
-#include <atomic>
-#include <cstdint>
-#include <deque>
-#include <functional>
-#include <iosfwd>
-#include <mutex>
-#include <utility>
-#include <vector>
-
-#include <folly/Function.h>
-#include <folly/Portability.h>
-#include <folly/Range.h>
-#include <folly/portability/SysUio.h>
-
-namespace folly {
-class AsyncIOOp;
-class IoUringOp;
-/**
- * An AsyncBaseOp represents a pending operation.  You may set a notification
- * callback or you may use this class's methods directly.
- *
- * The op must remain allocated until it is completed or canceled.
- */
-class AsyncBaseOp {
-  friend class AsyncBase;
-
- public:
-  using NotificationCallback = folly::Function<void(AsyncBaseOp*)>;
-
-  explicit AsyncBaseOp(NotificationCallback cb = NotificationCallback());
-  AsyncBaseOp(const AsyncBaseOp&) = delete;
-  AsyncBaseOp& operator=(const AsyncBaseOp&) = delete;
-  virtual ~AsyncBaseOp();
-
-  enum class State {
-    UNINITIALIZED,
-    INITIALIZED,
-    PENDING,
-    COMPLETED,
-    CANCELED,
-  };
-
-  /**
-   * Initiate a read request.
-   */
-  virtual void pread(int fd, void* buf, size_t size, off_t start) = 0;
-  void pread(int fd, Range<unsigned char*> range, off_t start) {
-    pread(fd, range.begin(), range.size(), start);
-  }
-  virtual void preadv(int fd, const iovec* iov, int iovcnt, off_t start) = 0;
-  virtual void pread(
-      int fd, void* buf, size_t size, off_t start, int /*buf_index*/) {
-    pread(fd, buf, size, start);
-  }
-
-  /**
-   * Initiate a write request.
-   */
-  virtual void pwrite(int fd, const void* buf, size_t size, off_t start) = 0;
-  void pwrite(int fd, Range<const unsigned char*> range, off_t start) {
-    pwrite(fd, range.begin(), range.size(), start);
-  }
-  virtual void pwritev(int fd, const iovec* iov, int iovcnt, off_t start) = 0;
-  virtual void pwrite(
-      int fd, const void* buf, size_t size, off_t start, int /*buf_index*/) {
-    pwrite(fd, buf, size, start);
-  }
-
-  // we support only these subclasses
-  virtual AsyncIOOp* getAsyncIOOp() = 0;
-  virtual IoUringOp* getIoUringOp() = 0;
-
-  // ostream output
-  virtual void toStream(std::ostream& os) const = 0;
-
-  /**
-   * Return the current operation state.
-   */
-  State state() const { return state_; }
-
-  /**
-   * user data get/set
-   */
-  void* getUserData() const { return userData_; }
-
-  void setUserData(void* userData) { userData_ = userData; }
-
-  /**
-   * Reset the operation for reuse.  It is an error to call reset() on
-   * an Op that is still pending.
-   */
-  virtual void reset(NotificationCallback cb = NotificationCallback()) = 0;
-
-  void setNotificationCallback(NotificationCallback cb) { cb_ = std::move(cb); }
-
-  /**
-   * Get the notification callback from the op.
-   *
-   * Note that this moves the callback out, leaving the callback in an
-   * uninitialized state! You must call setNotificationCallback before
-   * submitting the operation!
-   */
-  NotificationCallback getNotificationCallback() { return std::move(cb_); }
-
-  /**
-   * Retrieve the result of this operation.  Returns >=0 on success,
-   * -errno on failure (that is, using the Linux kernel error reporting
-   * conventions).  Use checkKernelError (folly/Exception.h) on the result to
-   * throw a std::system_error in case of error instead.
-   *
-   * It is an error to call this if the Op hasn't completed.
-   */
-  ssize_t result() const;
-
-  // debug helper
-  static std::string fd2name(int fd);
-
- protected:
-  void init();
-  void start();
-  void unstart();
-  void complete(ssize_t result);
-  void cancel();
-
-  NotificationCallback cb_;
-  std::atomic<State> state_;
-  ssize_t result_;
-  void* userData_{nullptr};
-};
-
-std::ostream& operator<<(std::ostream& os, const AsyncBaseOp& op);
-std::ostream& operator<<(std::ostream& os, AsyncBaseOp::State state);
-
-/**
- * Generic C++ interface around Linux IO(io_submit, io_uring)
- */
-class AsyncBase {
- public:
-  using Op = AsyncBaseOp;
-
-  enum PollMode {
-    NOT_POLLABLE,
-    POLLABLE,
-  };
-
-  /**
-   * Create an AsyncBase context capable of holding at most 'capacity' pending
-   * requests at the same time.  As requests complete, others can be scheduled,
-   * as long as this limit is not exceeded.
-   *
-   * If pollMode is POLLABLE, pollFd() will return a file descriptor that
-   * can be passed to poll / epoll / select and will become readable when
-   * any IOs on this AsyncBase have completed.  If you do this, you must use
-   * pollCompleted() instead of wait() -- do not read from the pollFd()
-   * file descriptor directly.
-   *
-   * You may use the same AsyncBase object from multiple threads, as long as
-   * there is only one concurrent caller of wait() / pollCompleted() / cancel()
-   * (perhaps by always calling it from the same thread, or by providing
-   * appropriate mutual exclusion).  In this case, pending() returns a snapshot
-   * of the current number of pending requests.
-   */
-  explicit AsyncBase(size_t capacity, PollMode pollMode = NOT_POLLABLE);
-  AsyncBase(const AsyncBase&) = delete;
-  AsyncBase& operator=(const AsyncBase&) = delete;
-  virtual ~AsyncBase();
-
-  /**
-   * Initialize context
-   */
-  virtual void initializeContext() = 0;
-
-  /**
-   * Wait for at least minRequests to complete.  Returns the requests that
-   * have completed; the returned range is valid until the next call to
-   * wait().  minRequests may be 0 to not block.
-   */
-  Range<Op**> wait(size_t minRequests);
-
-  /**
-   * Cancel all pending requests and return them; the returned range is
-   * valid until the next call to cancel().
-   */
-  Range<Op**> cancel();
-
-  /**
-   * Return the number of pending requests.
-   */
-  size_t pending() const { return pending_; }
-
-  /**
-   * Return the maximum number of requests that can be kept outstanding
-   * at any one time.
-   */
-  size_t capacity() const { return capacity_; }
-
-  /**
-   * Return the accumulative number of submitted I/O, since this object
-   * has been created.
-   */
-  size_t totalSubmits() const { return submitted_; }
-
-  /**
-   * If POLLABLE, return a file descriptor that can be passed to poll / epoll
-   * and will become readable when any async IO operations have completed.
-   * If NOT_POLLABLE, return -1.
-   */
-  int pollFd() const { return pollFd_; }
-
-  /**
-   * If POLLABLE, call instead of wait after the file descriptor returned
-   * by pollFd() became readable.  The returned range is valid until the next
-   * call to pollCompleted().
-   */
-  Range<Op**> pollCompleted();
-
-  /**
-   * Submit an op for execution.
-   */
-  void submit(Op* op);
-
-  /**
-   * Submit a range of ops for execution
-   */
-  int submit(Range<Op**> ops);
-
- protected:
-  virtual int drainPollFd() = 0;
-  void complete(Op* op, ssize_t result) { op->complete(result); }
-
-  void cancel(Op* op) { op->cancel(); }
-
-  bool isInit() const { return init_.load(std::memory_order_relaxed); }
-
-  void decrementPending(size_t num = 1);
-  virtual int submitOne(AsyncBase::Op* op) = 0;
-  virtual int submitRange(Range<AsyncBase::Op**> ops) = 0;
-
-  enum class WaitType { COMPLETE, CANCEL };
-  virtual Range<AsyncBase::Op**> doWait(
-      WaitType type,
-      size_t minRequests,
-      size_t maxRequests,
-      std::vector<Op*>& result) = 0;
-
-  std::atomic<bool> init_{false};
-  std::mutex initMutex_;
-
-  std::atomic<size_t> pending_{0};
-  std::atomic<size_t> submitted_{0};
-  const size_t capacity_;
-  const PollMode pollMode_;
-  int pollFd_{-1};
-  std::vector<Op*> completed_;
-  std::vector<Op*> canceled_;
-};
-
-/**
- * Wrapper around AsyncBase that allows you to schedule more requests than
- * the AsyncBase's object capacity.  Other requests are queued and processed
- * in a FIFO order.
- */
-class AsyncBaseQueue {
- public:
-  /**
-   * Create a queue, using the given AsyncBase object.
-   * The AsyncBase object may not be used by anything else until the
-   * queue is destroyed.
-   */
-  explicit AsyncBaseQueue(AsyncBase* asyncBase);
-  ~AsyncBaseQueue();
-
-  size_t queued() const { return queue_.size(); }
-
-  /**
-   * Submit an op to the AsyncBase queue.  The op will be queued until
-   * the AsyncBase object has room.
-   */
-  void submit(AsyncBaseOp* op);
-
-  /**
-   * Submit a delayed op to the AsyncBase queue; this allows you to postpone
-   * creation of the Op (which may require allocating memory, etc) until
-   * the AsyncBase object has room.
-   */
-  using OpFactory = std::function<AsyncBaseOp*()>;
-  void submit(OpFactory op);
-
- private:
-  void onCompleted(AsyncBaseOp* op);
-  void maybeDequeue();
-
-  AsyncBase* asyncBase_;
-
-  std::deque<OpFactory> queue_;
-};
-
-} // namespace folly
+#include <folly/io/async/AsyncBase.h>