refactor(io_context): peek-only as fast path for do_completion_part

.clang-format

@@ -3,7 +3,6 @@ BasedOnStyle: LLVM
 IndentWidth: 4
 TabWidth: 4
 Language: Cpp
-# AlignAfterOpenBracket: AlwaysBreak # BlockIndent
 AlignAfterOpenBracket: BlockIndent # BlockIndent
 AlignArrayOfStructures: Right
 AlignConsecutiveBitFields: "Consecutive"
@@ -14,8 +13,13 @@ AlignTrailingComments: true
 AllowAllArgumentsOnNextLine: true
 AllowAllConstructorInitializersOnNextLine: true
 AllowAllParametersOfDeclarationOnNextLine: true
+AlignConsecutiveShortCaseStatements: # clang-format 17
+  Enabled: true
+  AcrossEmptyLines: true
+  AcrossComments: true
+  AlignCaseColons: false
 AllowShortBlocksOnASingleLine: Empty
-AllowShortCaseLabelsOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: true
 AllowShortEnumsOnASingleLine: true
 AllowShortFunctionsOnASingleLine: InlineOnly
 AllowShortIfStatementsOnASingleLine: WithoutElse
@@ -49,7 +53,14 @@ IndentRequires: true # clang-format 14
 IndentWrappedFunctionNames: false
 InsertBraces: true # clang-format 15
 InsertNewlineAtEOF: true # clang-format 16
+IntegerLiteralSeparator: # clang-format 16
+  Binary: 8
+  Decimal: 0
+  Hex: 2
+  HexMinDigits: 8
 LambdaBodyIndentation: Signature
+LineEnding: LF # clang-format 16
+KeepEmptyLinesAtEOF: false # clang-format 17
 KeepEmptyLinesAtTheStartOfBlocks: false
 MaxEmptyLinesToKeep: 1
 NamespaceIndentation: Inner
@@ -58,6 +69,7 @@ PointerAlignment: Right
 QualifierAlignment: Left
 ReflowComments: true
 RequiresClausePosition: OwnLine # clang-format 15
+RequiresExpressionIndentation: OuterScope # clang-format 16
 SeparateDefinitionBlocks: Always
 ShortNamespaceLines: 5
 SortIncludes: "CaseSensitive"

example/netcat_timeout.cpp

@@ -7,12 +7,8 @@ using Socket = co_context::socket;
 
 void log_error(int err) {
     switch (err) {
-        case ECANCELED:
-            log::e("timeout\n");
-            break;
-        default:
-            log::e("%s\n", strerror(err));
-            break;
+        case ECANCELED: log::e("timeout\n"); break;
+        default:        log::e("%s\n", strerror(err)); break;
     }
 }
 

example/sem.cpp

@@ -21,7 +21,8 @@ constexpr auto time_tick{10ms};
 
 unsigned rnd() {
     static std::uniform_int_distribution<unsigned> distribution{
-        2U, 9U}; // [delays]
+        2U, 9U
+    }; // [delays]
     static std::random_device engine;
     static std::mt19937 noise{engine()};
     return distribution(noise);

example/sem_std.cpp

@@ -18,7 +18,8 @@ constexpr auto time_tick{10ms};
 
 unsigned rnd() {
     static std::uniform_int_distribution<unsigned> distribution{
-        2U, 9U}; // [delays]
+        2U, 9U
+    }; // [delays]
     static std::random_device engine;
     static std::mt19937 noise{engine()};
     return distribution(noise);

include/co_context/co/stop_token.hpp

@@ -108,7 +108,8 @@ class stop_token {
         bool *m_destroyed = nullptr;
         std::binary_semaphore m_done{0};
 
-        [[__gnu__::__nonnull__]] explicit stop_cb(cb_type *cb)
+        [[__gnu__::__nonnull__]]
+        explicit stop_cb(cb_type *cb)
             : m_callback(cb) {}
 
         void run() noexcept { m_callback(this); }
@@ -352,8 +353,8 @@ class stop_token {
             other.m_ptr = nullptr;
         }
 
-        stop_state_ref &operator= /*NOLINT*/ (const stop_state_ref &other
-        ) noexcept {
+        stop_state_ref &operator= /*NOLINT*/ (const stop_state_ref
+                                              & other) noexcept {
             if (auto *ptr = other.m_ptr; ptr != m_ptr) {
                 if (ptr) {
                     ptr->add_owner();

include/co_context/co/when_any.hpp

@@ -157,7 +157,8 @@ task<detail::any_return_type<Ts...>> any(task<Ts> &&...node) {
         co_return meta_ptr->idx;
     } else {
         co_return detail::any_tuple<Ts...>{
-            meta_ptr->idx, std::move(meta_ptr->buffer)};
+            meta_ptr->idx, std::move(meta_ptr->buffer)
+        };
     }
 }
 

include/co_context/config.hpp

@@ -131,7 +131,7 @@ namespace config {
      * missed than to ensure accuracy, it is recommended to set bias to 0.
      */
     // inline constexpr int64_t timeout_bias_nanosecond = 0;
-    inline constexpr int64_t timeout_bias_nanosecond = -60'000;
+    inline constexpr int64_t timeout_bias_nanosecond = -30'000;
     // ========================================================================
 
 } // namespace config

include/co_context/detail/lazy_io_awaiter.hpp

@@ -210,18 +210,16 @@ struct lazy_recvmsg : lazy_awaiter {
 
 #if LIBURINGCXX_IS_KERNEL_REACH(5, 20)
 struct lazy_recvmsg_multishot : lazy_awaiter {
-    inline lazy_recvmsg_multishot(
-        int fd, msghdr *msg, unsigned flags
-    ) noexcept {
+    inline
+    lazy_recvmsg_multishot(int fd, msghdr *msg, unsigned flags) noexcept {
         sqe->prep_recvmsg_multishot(fd, msg, flags);
     }
 };
 #endif
 
 struct lazy_sendmsg : lazy_awaiter {
-    inline lazy_sendmsg(
-        int fd, const msghdr *msg, unsigned int flags
-    ) noexcept {
+    inline
+    lazy_sendmsg(int fd, const msghdr *msg, unsigned int flags) noexcept {
         sqe->prep_sendmsg(fd, msg, flags);
     }
 };
@@ -499,9 +497,8 @@ struct lazy_link_timeout
 };
 
 struct lazy_connect : lazy_awaiter {
-    inline lazy_connect(
-        int sockfd, const sockaddr *addr, socklen_t addrlen
-    ) noexcept {
+    inline
+    lazy_connect(int sockfd, const sockaddr *addr, socklen_t addrlen) noexcept {
         sqe->prep_connect(sockfd, addr, addrlen);
     }
 };
@@ -513,17 +510,15 @@ struct lazy_files_update : lazy_awaiter {
 };
 
 struct lazy_fallocate : lazy_awaiter {
-    inline lazy_fallocate(
-        int fd, int mode, uint64_t offset, uint64_t len
-    ) noexcept {
+    inline
+    lazy_fallocate(int fd, int mode, uint64_t offset, uint64_t len) noexcept {
         sqe->prep_fallocate(fd, mode, offset, len);
     }
 };
 
 struct lazy_openat : lazy_awaiter {
-    inline lazy_openat(
-        int dfd, const char *path, int flags, mode_t mode
-    ) noexcept {
+    inline
+    lazy_openat(int dfd, const char *path, int flags, mode_t mode) noexcept {
         sqe->prep_openat(dfd, path, flags, mode);
     }
 };
@@ -554,9 +549,8 @@ struct lazy_read : lazy_awaiter {
 };
 
 struct lazy_write : lazy_awaiter {
-    inline lazy_write(
-        int fd, std::span<const char> buf, uint64_t offset
-    ) noexcept {
+    inline
+    lazy_write(int fd, std::span<const char> buf, uint64_t offset) noexcept {
         sqe->prep_write(fd, buf, offset);
     }
 };
@@ -574,9 +568,8 @@ struct lazy_statx : lazy_awaiter {
 };
 
 struct lazy_fadvise : lazy_awaiter {
-    inline lazy_fadvise(
-        int fd, uint64_t offset, off_t len, int advice
-    ) noexcept {
+    inline
+    lazy_fadvise(int fd, uint64_t offset, off_t len, int advice) noexcept {
         sqe->prep_fadvise(fd, offset, len, advice);
     }
 };
@@ -588,9 +581,8 @@ struct lazy_madvise : lazy_awaiter {
 };
 
 struct lazy_send : lazy_awaiter {
-    inline lazy_send(
-        int sockfd, std::span<const char> buf, int flags
-    ) noexcept {
+    inline
+    lazy_send(int sockfd, std::span<const char> buf, int flags) noexcept {
         sqe->prep_send(sockfd, buf, flags);
     }
 };
@@ -631,9 +623,8 @@ struct lazy_recv : lazy_awaiter {
 
 #if LIBURINGCXX_IS_KERNEL_REACH(5, 20)
 struct lazy_recv_multishot : lazy_awaiter {
-    inline lazy_recv_multishot(
-        int sockfd, std::span<char> buf, int flags
-    ) noexcept {
+    inline
+    lazy_recv_multishot(int sockfd, std::span<char> buf, int flags) noexcept {
         sqe->prep_recv_multishot(sockfd, buf, flags);
     }
 };
@@ -757,9 +748,8 @@ struct lazy_linkat : lazy_awaiter {
 };
 
 struct lazy_link : lazy_awaiter {
-    inline lazy_link(
-        const char *oldpath, const char *newpath, int flags
-    ) noexcept {
+    inline
+    lazy_link(const char *oldpath, const char *newpath, int flags) noexcept {
         sqe->prep_link(oldpath, newpath, flags);
     }
 };
@@ -807,9 +797,8 @@ struct lazy_setxattr : lazy_awaiter {
 };
 
 struct lazy_fgetxattr : lazy_awaiter {
-    inline lazy_fgetxattr(
-        int fd, const char *name, char *value, size_t len
-    ) noexcept {
+    inline
+    lazy_fgetxattr(int fd, const char *name, char *value, size_t len) noexcept {
         sqe->prep_fgetxattr(fd, name, value, len);
     }
 };

include/co_context/detail/trival_task.hpp

@@ -44,7 +44,8 @@ class trival_task {
 
         trival_task get_return_object() noexcept {
             return trival_task{
-                std::coroutine_handle<promise_type>::from_promise(*this)};
+                std::coroutine_handle<promise_type>::from_promise(*this)
+            };
         }
 
         constexpr void unhandled_exception() noexcept {}

include/co_context/detail/user_data.hpp

@@ -15,6 +15,7 @@ enum class user_data_type : uint8_t {
     task_info_ptr,
     coroutine_handle,
     task_info_ptr__link_sqe,
+    msg_ring,
     none
 };
 

include/co_context/detail/worker_meta.hpp

@@ -109,6 +109,8 @@ struct worker_meta final {
 
     void wait_uring() noexcept;
 
+    bool peek_uring() noexcept;
+
     [[nodiscard]]
     cur_t number_to_schedule() const noexcept {
         const auto &cur = this->reap_cur;
@@ -208,7 +210,7 @@ inline void worker_meta::co_spawn_safe_msg_ring(std::coroutine_handle<> handle
     );
     auto *const sqe = from.get_free_sqe();
     auto user_data = reinterpret_cast<uint64_t>(handle.address())
-                     | uint8_t(user_data_type::coroutine_handle);
+                     | uint8_t(user_data_type::msg_ring);
     sqe->prep_msg_ring(ring_fd, 0, user_data, 0);
     sqe->set_data(uint64_t(reserved_user_data::nop));
 #if LIBURINGCXX_IS_KERNEL_REACH(5, 17)
@@ -253,4 +255,10 @@ inline void worker_meta::wait_uring() noexcept {
     ring.wait_cq_entry(_);
 }
 
+inline bool worker_meta::peek_uring() noexcept {
+    [[maybe_unused]] const liburingcxx::cq_entry *cqe;
+    ring.peek_cq_entry(cqe);
+    return cqe != nullptr;
+}
+
 } // namespace co_context::detail

include/co_context/generator.hpp

@@ -338,7 +338,8 @@ class _Gen_promise_base {
                 }
             }(std::allocator_arg, _Elem.allocator,
               ::std::ranges::begin(_Elem.range),
-              ::std::ranges::end(_Elem.range))};
+              ::std::ranges::end(_Elem.range))
+        };
     }
 
 #pragma GCC diagnostic pop
@@ -567,7 +568,8 @@ class generator
         generator get_return_object() noexcept {
             return generator{
                 _Gen_secret_tag{},
-                std::coroutine_handle<promise_type>::from_promise(*this)};
+                std::coroutine_handle<promise_type>::from_promise(*this)
+            };
         }
     };
 
@@ -600,7 +602,8 @@ class generator
         return _Gen_iter<_Value, _Ref>{
             _Gen_secret_tag{},
             std::coroutine_handle<_Gen_promise_base<_Gen_yield_t<_Ref>>>::
-                from_address(_Coro.address())};
+                from_address(_Coro.address())
+        };
     }
 
     [[nodiscard]]

include/co_context/lazy_io.hpp

@@ -127,7 +127,8 @@ inline namespace lazy {
         unsigned flags
     ) noexcept {
         return detail::lazy_poll_update{
-            old_user_data, new_user_data, poll_mask, flags};
+            old_user_data, new_user_data, poll_mask, flags
+        };
     }
 
     [[CO_CONTEXT_AWAIT_HINT]]
@@ -400,7 +401,8 @@ inline namespace lazy {
         unsigned buf_index
     ) noexcept {
         return detail::lazy_send_zc_fixed{
-            sockfd, buf, flags, zc_flags, buf_index};
+            sockfd, buf, flags, zc_flags, buf_index
+        };
     }
 
     [[CO_CONTEXT_AWAIT_HINT]]
@@ -553,7 +555,8 @@ inline namespace lazy {
         uint32_t cqe_flags
     ) noexcept {
         return detail::lazy_msg_ring_cqe_flags{
-            fd, cqe_res, cqe_user_data, flags, cqe_flags};
+            fd, cqe_res, cqe_user_data, flags, cqe_flags
+        };
     }
 #endif
 
@@ -600,7 +603,8 @@ inline namespace lazy {
         unsigned int flags
     ) noexcept {
         return detail::lazy_socket_direct{
-            domain, type, protocol, file_index, flags};
+            domain, type, protocol, file_index, flags
+        };
     }
 
     [[CO_CONTEXT_AWAIT_HINT]]