Read/write loop test working

uring.cc

@@ -0,0 +1,122 @@
+#include "uring.h"
+
+#include <glog/logging.h>
+
+namespace uring {
+
+URing::URing(uint32_t num_entries)
+    : ring_fd_(io_uring_queue_init(num_entries, &ring_, 0)),
+      entries_(num_entries * 3),
+      free_head_(&entries_.at(0)) {
+  PCHECK(ring_fd_ >= 0) << "io_uring_queue_init()";
+
+  // Chain the entries together into a list that we'll use as a free list for
+  // future allocation.
+  Entry *prev = nullptr;
+  for (auto &entry : entries_) {
+    entry.free_next = prev;
+    prev = &entry;
+  }
+}
+
+URing::~URing() { io_uring_queue_exit(&ring_); }
+
+void URing::Submit() { io_uring_submit(&ring_); }
+
+void URing::Wait() {
+  io_uring_cqe *cqe;
+  PCHECK(io_uring_wait_cqe(&ring_, &cqe) == 0);
+  ProcessCQE(cqe);
+}
+
+bool URing::Try() {
+  io_uring_cqe *cqe = nullptr;
+  PCHECK(io_uring_peek_cqe(&ring_, &cqe) == 0);
+  if (cqe) {
+    ProcessCQE(cqe);
+    return true;
+  }
+  return false;
+}
+
+void URing::write(int fd, const void *buf, size_t count,
+                  const std::function<void(int32_t res)> &callback) {
+  std::vector<iovec> vecs{
+      {
+          .iov_base = const_cast<void *>(buf),
+          .iov_len = count,
+      },
+  };
+  writev(fd, vecs, callback);
+}
+
+void URing::writev(int fd, const std::vector<iovec> &vecs,
+                   const std::function<void(int32_t res)> &callback) {
+  pwritev(fd, vecs, 0, callback);
+}
+
+void URing::pwritev(int fd, const std::vector<iovec> &vecs, off_t offset,
+                    const std::function<void(int32_t res)> &callback) {
+  auto *entry = GetEntry(callback);
+  entry->vecs = vecs;
+
+  auto *sqe = GetSQE();
+  io_uring_prep_writev(sqe, fd, entry->vecs.data(), entry->vecs.size(), offset);
+  io_uring_sqe_set_data(sqe, reinterpret_cast<void *>(entry));
+}
+
+void URing::read(int fd, const void *buf, size_t count,
+                 const std::function<void(int32_t res)> &callback) {
+  std::vector<iovec> vecs{
+      {
+          .iov_base = const_cast<void *>(buf),
+          .iov_len = count,
+      },
+  };
+  readv(fd, vecs, callback);
+}
+
+void URing::readv(int fd, const std::vector<iovec> &vecs,
+                  const std::function<void(int32_t res)> &callback) {
+  preadv(fd, vecs, 0, callback);
+}
+
+void URing::preadv(int fd, const std::vector<iovec> &vecs, off_t offset,
+                   const std::function<void(int32_t res)> &callback) {
+  auto *entry = GetEntry(callback);
+  entry->vecs = vecs;
+
+  auto *sqe = GetSQE();
+  io_uring_prep_readv(sqe, fd, entry->vecs.data(), entry->vecs.size(), offset);
+  io_uring_sqe_set_data(sqe, reinterpret_cast<void *>(entry));
+}
+
+URing::Entry *URing::GetEntry(
+    const std::function<void(int32_t res)> &callback) {
+  CHECK(free_head_);
+  auto *entry = free_head_;
+  free_head_ = entry->free_next;
+  entry->callback = callback;
+  return entry;
+}
+
+void URing::PutEntry(Entry *entry, int32_t res) {
+  entry->callback(res);
+  entry->free_next = free_head_;
+  free_head_ = entry;
+}
+
+io_uring_sqe *URing::GetSQE() {
+  auto *sqe = io_uring_get_sqe(&ring_);
+  // TODO: automatically Submit() on full submit queue? spin? something else?
+  CHECK(sqe);
+  return sqe;
+}
+
+void URing::ProcessCQE(io_uring_cqe *cqe) {
+  Entry *entry = reinterpret_cast<Entry *>(io_uring_cqe_get_data(cqe));
+  PutEntry(entry, cqe->res);
+  io_uring_cqe_seen(&ring_, cqe);
+}
+
+}  // namespace uring