From 34a9b3aa6a9d6ade41cecdf290435c39c0bd64bb Mon Sep 17 00:00:00 2001
From: Charles Cabergs <me@cacharle.xyz>
Date: Wed, 23 Apr 2025 21:30:24 +0200
Subject: [PATCH] Add zmq_timers support (#657)

* Add zmq_timers support

* Add zmq_timers unit tests
---
 CMakeLists.txt       |  1 +
 tests/CMakeLists.txt |  1 +
 tests/timers.cpp     | 80 ++++++++++++++++++++++++++++++++++++++++++++
 zmq.hpp              | 79 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 161 insertions(+)
 create mode 100644 tests/timers.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b45e91d..3035755 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,7 @@
 cmake_minimum_required(VERSION 3.11)
 
 list (APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
 include (DetectCPPZMQVersion)
 
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index e20aaaa..3821c5c 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -30,6 +30,7 @@ add_executable(
     codec_multipart.cpp
     monitor.cpp
     utilities.cpp
+    timers.cpp
 )
 
 target_include_directories(unit_tests PUBLIC ${CATCH_MODULE_PATH})
diff --git a/tests/timers.cpp b/tests/timers.cpp
new file mode 100644
index 0000000..4229fd5
--- /dev/null
+++ b/tests/timers.cpp
@@ -0,0 +1,80 @@
+#include <catch2/catch_all.hpp>
+#include <zmq.hpp>
+
+#include <type_traits>
+#include <thread>
+#include <chrono>
+
+#if defined(ZMQ_CPP11) && defined(ZMQ_HAVE_TIMERS)
+
+static_assert(std::is_default_constructible<zmq::timers>::value);
+static_assert(!std::is_copy_constructible<zmq::timers>::value);
+static_assert(!std::is_copy_assignable<zmq::timers>::value);
+
+TEST_CASE("timers constructor", "[timers]")
+{
+    zmq::timers timers;
+    CHECK(!timers.timeout().has_value());
+}
+
+TEST_CASE("timers add/execute", "[timers]")
+{
+    using namespace std::chrono_literals;
+    zmq::timers timers;
+    bool handler_ran = false;
+    timers.add(4ms, [](auto, void *arg) { *(bool *) arg = true; }, &handler_ran);
+    CHECK(timers.timeout().has_value());
+    CHECK(!handler_ran);
+    std::this_thread::sleep_for(10ms);
+    timers.execute();
+    CHECK(handler_ran);
+}
+
+TEST_CASE("timers add/cancel", "[timers]")
+{
+    using namespace std::chrono_literals;
+    zmq::timers timers;
+    bool handler_ran = false;
+    auto id =
+      timers.add(4ms, [](auto, void *arg) { *(bool *) arg = true; }, &handler_ran);
+    CHECK(timers.timeout().has_value());
+    CHECK(!handler_ran);
+    timers.cancel(id);
+    CHECK(!timers.timeout().has_value());
+    CHECK(!handler_ran);
+}
+
+TEST_CASE("timers set_interval", "[timers]")
+{
+    using namespace std::chrono_literals;
+    zmq::timers timers;
+    bool handler_ran = false;
+    // Interval of 4 hours should never run like this
+    auto id =
+      timers.add(4h, [](auto, void *arg) { *(bool *) arg = true; }, &handler_ran);
+    CHECK(timers.timeout().has_value());
+    CHECK(!handler_ran);
+    // Change the interval to 4ms and wait for it to timeout
+    timers.set_interval(id, 4ms);
+    std::this_thread::sleep_for(10ms);
+    timers.execute();
+    CHECK(handler_ran);
+}
+
+TEST_CASE("timers reset", "[timers]")
+{
+    using namespace std::chrono_literals;
+    zmq::timers timers;
+    bool handler_ran = false;
+    auto id =
+      timers.add(4ms, [](auto, void *arg) { *(bool *) arg = true; }, &handler_ran);
+    CHECK(timers.timeout().has_value());
+    std::this_thread::sleep_for(10ms);
+    // Available to be executed but we reset it
+    timers.reset(id);
+    CHECK(timers.timeout().has_value());
+    CHECK(!handler_ran);
+
+}
+
+#endif // defined(ZMQ_CPP11) && defined(ZMQ_HAVE_TIMERS)
diff --git a/zmq.hpp b/zmq.hpp
index 5b22687..363f74b 100644
--- a/zmq.hpp
+++ b/zmq.hpp
@@ -2794,6 +2794,85 @@ inline std::ostream &operator<<(std::ostream &os, const message_t &msg)
     return os << msg.str();
 }
 
+#if defined(ZMQ_CPP11) && defined(ZMQ_HAVE_TIMERS)
+
+class timers
+{
+  public:
+    using id_t = int;
+    using fn_t = zmq_timer_fn;
+
+#if CPPZMQ_HAS_OPTIONAL
+    using timeout_result_t = std::optional<std::chrono::milliseconds>;
+#else
+    using timeout_result_t = detail::trivial_optional<std::chrono::milliseconds>;
+#endif
+
+    timers() : _timers(zmq_timers_new())
+    {
+        if (_timers == nullptr)
+            throw error_t();
+    }
+
+    timers(const timers &other) = delete;
+    timers &operator=(const timers &other) = delete;
+
+    ~timers()
+    {
+        int rc = zmq_timers_destroy(&_timers);
+        ZMQ_ASSERT(rc == 0);
+    }
+
+    id_t add(std::chrono::milliseconds interval, zmq_timer_fn handler, void *arg)
+    {
+        id_t timer_id = zmq_timers_add(_timers, interval.count(), handler, arg);
+        if (timer_id == -1)
+            throw zmq::error_t();
+        return timer_id;
+    }
+
+    void cancel(id_t timer_id)
+    {
+        int rc = zmq_timers_cancel(_timers, timer_id);
+        if (rc == -1)
+            throw zmq::error_t();
+    }
+
+    void set_interval(id_t timer_id, std::chrono::milliseconds interval)
+    {
+        int rc = zmq_timers_set_interval(_timers, timer_id, interval.count());
+        if (rc == -1)
+            throw zmq::error_t();
+    }
+
+    void reset(id_t timer_id)
+    {
+        int rc = zmq_timers_reset(_timers, timer_id);
+        if (rc == -1)
+            throw zmq::error_t();
+    }
+
+    timeout_result_t timeout() const
+    {
+        int timeout = zmq_timers_timeout(_timers);
+        if (timeout == -1)
+            return timeout_result_t{};
+        return std::chrono::milliseconds{timeout};
+    }
+
+    void execute()
+    {
+        int rc = zmq_timers_execute(_timers);
+        if (rc == -1)
+            throw zmq::error_t();
+    }
+
+  private:
+    void *_timers;
+};
+
+#endif // defined(ZMQ_CPP11) && defined(ZMQ_HAVE_TIMERS)
+
 } // namespace zmq
 
 #endif // __ZMQ_HPP_INCLUDED__