co::Coroutine -> toolbelt::Poller

CMakeLists.txt

@@ -35,19 +35,6 @@ FetchContent_Declare(
 FetchContent_MakeAvailable(abseil)
 # Abseil provides targets like absl::base, absl::strings, etc.
 
-# --- External Dependency: co ---
-# cpp_toolbelt depends on co, so we need to fetch and make it available.
-FetchContent_Declare(
-    co
-    GIT_REPOSITORY https://github.com/dallison/co.git
-    GIT_TAG cf1252b2f5952d7cba83b67dd69288971c0a2b57
-    # Pass architecture settings to co's CMake build
-    CMAKE_ARGS
-        CMAKE_OSX_ARCHITECTURES="${CMAKE_OSX_ARCHITECTURES}"
-)
-FetchContent_MakeAvailable(co)
-# co provides the 'co' target.
-
 # --- toolbelt Library Target ---
 # Corresponds to //toolbelt:toolbelt in Bazel
 # Source files are omitted here for manual addition by the user.
@@ -67,6 +54,8 @@ add_library(toolbelt STATIC
     toolbelt/payload_buffer.h
     toolbelt/pipe.cc
     toolbelt/pipe.h
+    toolbelt/poller.cc
+    toolbelt/poller.h
     toolbelt/sockets.cc
     toolbelt/sockets.h
     toolbelt/table.cc
@@ -88,7 +77,6 @@ target_link_libraries(toolbelt PUBLIC
     absl::log # Added as it's used by toolbelt/logging
     absl::time # Added as it's used by toolbelt/time
     absl::synchronization # Added as it's used by toolbelt/utilities/thread_pool
-    co # Link against the co library
 )
 
 # Note: If there are tests in cpp_toolbelt, they would need a separate target

MODULE.bazel

@@ -15,4 +15,9 @@ bazel_dep(name = "rules_cc", version = "0.2.17")
 #   module_name = "coroutines",
 #   path = "../co",
 # )
+git_override(
+    module_name = "coroutines",
+    commit = "21e28c2c6b28ea1f4cf5f9948a9c6dd379b5ec7e",
+    remote = "https://github.com/mikael-s-persson/co.git",
+)
 

toolbelt/BUILD.bazel

@@ -5,6 +5,7 @@ load("@rules_cc//cc:defs.bzl", "cc_library", "cc_test")
 cc_library(
     name = "toolbelt",
     srcs = [
+        "async_waiter.cc",
         "color.cc",
         "fd.cc",
         "hexdump.cc",
@@ -17,6 +18,7 @@ cc_library(
         "stacktrace.cc",
     ],
     hdrs = [
+        "async_waiter.h",
         "bitset.h",
         "clock.h",
         "color.h",
@@ -37,7 +39,6 @@ cc_library(
         "@abseil-cpp//absl/strings",
         "@abseil-cpp//absl/strings:str_format",
         "@abseil-cpp//absl/types:span",
-        "@coroutines//:co",
     ],
 )
 
@@ -91,6 +92,7 @@ cc_test(
         "@abseil-cpp//absl/status:status_matchers",
         "@abseil-cpp//absl/status:statusor",
         "@googletest//:gtest_main",
+        "@coroutines//:co",
     ],
 )
 
@@ -105,6 +107,7 @@ cc_test(
         "@abseil-cpp//absl/status:status_matchers",
         "@abseil-cpp//absl/status:statusor",
         "@googletest//:gtest_main",
+        "@coroutines//:co",
     ],
 )
 

toolbelt/async_waiter.cc

@@ -0,0 +1,60 @@
+// Copyright 2026 Mikael Persson
+// All Rights Reserved
+// See LICENSE file for licensing information.
+#include "toolbelt/async_waiter.h"
+
+#include <chrono>
+#include <poll.h>
+#include <thread>
+
+namespace toolbelt {
+
+PosixPoller::PosixPoller(uint64_t yield_sleep_ns) : AsyncWaiter(), yield_sleep_ns_(yield_sleep_ns) {}
+
+void PosixPoller::Yield() const {
+  if (yield_sleep_ns_ == 0) {
+    std::this_thread::yield();
+  } else {
+    std::this_thread::sleep_for(std::chrono::nanoseconds(yield_sleep_ns_));
+  }
+}
+
+void PosixPoller::Nanosleep(uint64_t ns) const {
+  std::this_thread::sleep_for(std::chrono::nanoseconds(ns));
+}
+
+void PosixPoller::AddToUserWaitFds(int fd, uint32_t event_mask) const {
+  user_fds_.push_back({.fd = fd, .events = short(event_mask)});
+}
+
+int PosixPoller::PollImpl(std::vector<struct pollfd> &fds, int timeout_ms) const {
+  int ret = ::poll(user_fds_.data(), user_fds_.size(), timeout_ms);
+  if (ret < 0) {
+    return -2;
+  }
+  if (ret == 0) {
+    return -1;
+  }
+  for (auto &pfd : fds) {
+    if (pfd.revents & (pfd.events | POLLOUT)) {
+      return pfd.fd;
+    }
+  }
+  return -1;
+}
+
+int PosixPoller::WaitOnUserWaitFds(uint64_t timeout_ns) const {
+  int timeout_ms = -1;
+  if (timeout_ns != 0) {
+    timeout_ms = std::max(1, static_cast<int>(timeout_ns / 1000000ULL));
+  }
+  int result = PollImpl(user_fds_, timeout_ms);
+  user_fds_.clear();
+  return result;
+}
+
+int PosixPoller::PollWithMutableFds(std::vector<struct pollfd> &fds) const {
+  return PollImpl(fds, 0);
+}
+
+} // namespace toolbelt