Add sdevent C++ wrappers
Add C++ wrappers around select sd-event APIs, for a more C++ like
programming API.
Includes support for core sd_event and timer related sd_event_source
APIs.
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
Change-Id: I10ac5406c9f8831b4efb294d3aef36026469d4a5
diff --git a/src/sdevent/event.hpp b/src/sdevent/event.hpp
new file mode 100644
index 0000000..5462202
--- /dev/null
+++ b/src/sdevent/event.hpp
@@ -0,0 +1,140 @@
+#pragma once
+
+#include <chrono>
+#include <memory>
+#include <sdbusplus/bus.hpp>
+#include <systemd/sd-event.h>
+
+// TODO: openbmc/openbmc#1720 - add error handling for sd_event API failures
+
+namespace sdevent
+{
+namespace event
+{
+namespace timer
+{
+class Timer;
+} // namespace timer
+}
+namespace event
+{
+
+using EventPtr = sd_event*;
+class Event;
+
+/** @brief Get an instance of the 'default' event. */
+Event newDefault();
+
+namespace details
+{
+
+/** @brief unique_ptr functor to release an event reference. */
+struct EventDeleter
+{
+ void operator()(sd_event* ptr) const
+ {
+ deleter(ptr);
+ }
+
+ decltype(&sd_event_unref) deleter = sd_event_unref;
+};
+
+/* @brief Alias 'event' to a unique_ptr type for auto-release. */
+using Event = std::unique_ptr<sd_event, EventDeleter>;
+
+} // namespace details
+
+/** @class Event
+ * @brief Provides C++ bindings to the sd_event_* class functions.
+ */
+class Event
+{
+ public:
+ /* Define all of the basic class operations:
+ * Not allowed:
+ * - Default constructor to avoid nullptrs.
+ * - Copy operations due to internal unique_ptr.
+ * Allowed:
+ * - Move operations.
+ * - Destructor.
+ */
+ Event() = delete;
+ Event(const Event&) = delete;
+ Event& operator=(const Event&) = delete;
+ Event(Event&&) = default;
+ Event& operator=(Event&&) = default;
+ ~Event() = default;
+
+ /** @brief Conversion constructor from 'EventPtr'.
+ *
+ * Increments ref-count of the event-pointer and releases it when
+ * done.
+ */
+ explicit Event(EventPtr e);
+
+ /** @brief Constructor for 'Event'.
+ *
+ * Takes ownership of the event-pointer and releases it when done.
+ */
+ Event(EventPtr e, std::false_type);
+
+ /** @brief Release ownership of the stored event-pointer. */
+ EventPtr release()
+ {
+ return evt.release();
+ }
+
+ /** @brief Wait indefinitely for new event sources. */
+ void loop()
+ {
+ sd_event_loop(evt.get());
+ }
+
+ /** @brief Attach to a DBus loop. */
+ void attach(sdbusplus::bus::bus& bus)
+ {
+ bus.attach_event(evt.get(), SD_EVENT_PRIORITY_NORMAL);
+ }
+
+ /** @brief C++ wrapper for sd_event_now. */
+ auto now()
+ {
+ using namespace std::chrono;
+
+ uint64_t usec;
+ sd_event_now(evt.get(), CLOCK_MONOTONIC, &usec);
+ microseconds d(usec);
+ return steady_clock::time_point(d);
+ }
+
+ friend class timer::Timer;
+
+ private:
+
+ EventPtr get()
+ {
+ return evt.get();
+ }
+
+ details::Event evt;
+};
+
+inline Event::Event(EventPtr l) : evt(sd_event_ref(l))
+{
+
+}
+
+inline Event::Event(EventPtr l, std::false_type) : evt(l)
+{
+
+}
+
+inline Event newDefault()
+{
+ sd_event* e = nullptr;
+ sd_event_default(&e);
+ return Event(e, std::false_type());
+}
+
+} // namespace event
+} // namespace sdevent
diff --git a/src/sdevent/source.hpp b/src/sdevent/source.hpp
new file mode 100644
index 0000000..812f0a3
--- /dev/null
+++ b/src/sdevent/source.hpp
@@ -0,0 +1,113 @@
+#pragma once
+
+#include <chrono>
+#include <memory>
+#include <systemd/sd-event.h>
+
+// TODO: openbmc/openbmc#1720 - add error handling for sd_event API failures
+
+namespace sdevent
+{
+namespace source
+{
+
+using SourcePtr = sd_event_source*;
+
+namespace details
+{
+
+/** @brief unique_ptr functor to release a source reference. */
+struct SourceDeleter
+{
+ void operator()(sd_event_source* ptr) const
+ {
+ deleter(ptr);
+ }
+
+ decltype(&sd_event_source_unref) deleter = sd_event_source_unref;
+};
+
+/* @brief Alias 'source' to a unique_ptr type for auto-release. */
+using source = std::unique_ptr<sd_event_source, SourceDeleter>;
+
+} // namespace details
+
+/** @class Source
+ * @brief Provides C++ bindings to the sd_event_source* functions.
+ */
+class Source
+{
+ public:
+ /* Define all of the basic class operations:
+ * Not allowed:
+ * - Default constructor to avoid nullptrs.
+ * - Copy operations due to internal unique_ptr.
+ * Allowed:
+ * - Move operations.
+ * - Destructor.
+ */
+ Source() = delete;
+ Source(const Source&) = delete;
+ Source& operator=(const Source&) = delete;
+ Source(Source&&) = default;
+ Source& operator=(Source&&) = default;
+ ~Source() = default;
+
+ /** @brief Conversion constructor from 'SourcePtr'.
+ *
+ * Increments ref-count of the source-pointer and releases it
+ * when done.
+ */
+ explicit Source(SourcePtr s) : src(sd_event_source_ref(s)) {}
+
+ /** @brief Constructor for 'source'.
+ *
+ * Takes ownership of the source-pointer and releases it when done.
+ */
+ Source(SourcePtr s, std::false_type) : src(s) {}
+
+ /** @brief Check if source contains a real pointer. (non-nullptr). */
+ explicit operator bool() const
+ {
+ return bool(src);
+ }
+
+ /** @brief Test whether or not the source can generate events. */
+ auto enabled()
+ {
+ int enabled;
+ sd_event_source_get_enabled(src.get(), &enabled);
+ return enabled;
+ }
+
+ /** @brief Allow the source to generate events. */
+ void enable(int enable)
+ {
+ sd_event_source_set_enabled(src.get(), enable);
+ }
+
+ /** @brief Set the expiration on a timer source. */
+ void setTime(
+ const std::chrono::steady_clock::time_point& expires)
+ {
+ using namespace std::chrono;
+ auto epoch = expires.time_since_epoch();
+ auto time = duration_cast<microseconds>(epoch);
+ sd_event_source_set_time(src.get(), time.count());
+ }
+
+ /** @brief Get the expiration on a timer source. */
+ auto getTime()
+ {
+ using namespace std::chrono;
+ uint64_t usec;
+ sd_event_source_get_time(src.get(), &usec);
+ microseconds d(usec);
+ return steady_clock::time_point(d);
+ }
+
+ private:
+ details::source src;
+};
+} // namespace source
+} // namespace sdevent
diff --git a/src/sdevent/timer.hpp b/src/sdevent/timer.hpp
new file mode 100644
index 0000000..863e725
--- /dev/null
+++ b/src/sdevent/timer.hpp
@@ -0,0 +1,139 @@
+#pragma once
+
+#include <chrono>
+#include <functional>
+#include <memory>
+#include <systemd/sd-event.h>
+
+#include "sdevent/source.hpp"
+#include "sdevent/event.hpp"
+
+// TODO: openbmc/openbmc#1720 - add error handling for sd_event API failures
+
+namespace sdevent
+{
+namespace event
+{
+namespace timer
+{
+
+/** @class Timer
+ * @brief Provides C++ bindings to the sd_event_source* timer functions.
+ */
+class Timer
+{
+ public:
+ /* Define all of the basic class operations:
+ * Not allowed:
+ * - Default constructor to avoid nullptrs.
+ * - Copy operations due to internal unique_ptr.
+ * Allowed:
+ * - Move operations.
+ * - Destructor.
+ */
+ Timer() = delete;
+ Timer(const Timer&) = delete;
+ Timer& operator=(const Timer&) = delete;
+ Timer(Timer&&) = default;
+ Timer& operator=(Timer&&) = default;
+ ~Timer() = default;
+
+ using Callback = std::function<void(source::Source&)>;
+
+ /** @brief Register a timer callback.
+ *
+ * @param[in] event - The event to register on.
+ * @param[in] expires - The initial timer expiration time.
+ * @param[in] callback - The callback method.
+ */
+ Timer(
+ sdevent::event::Event& event,
+ const std::chrono::steady_clock::time_point& expires,
+ Callback callback)
+ : src(nullptr),
+ cb(std::make_unique<Callback>(std::move(callback)))
+ {
+ using namespace std::chrono;
+ auto epoch = expires.time_since_epoch();
+ auto time = duration_cast<microseconds>(epoch);
+ sd_event_source* source = nullptr;
+ sd_event_add_time(
+ event.get(),
+ &source,
+ CLOCK_MONOTONIC,
+ time.count(),
+ 0,
+ callCallback,
+ cb.get());
+// **INDENT-OFF**
+ src = decltype(src){source, std::false_type()};
+// **INDENT-ON**
+ }
+
+ /** @brief Register a disabled timer callback.
+ *
+ * @param[in] event - The event to register on.
+ * @param[in] callback - The callback method.
+ */
+ Timer(
+ sdevent::event::Event& event,
+ Callback callback)
+ : src(nullptr),
+ cb(std::make_unique<Callback>(std::move(callback)))
+ {
+ sd_event_source* source = nullptr;
+ sd_event_add_time(
+ event.get(),
+ &source,
+ CLOCK_MONOTONIC,
+ ULLONG_MAX,
+ 0,
+ callCallback,
+ cb.get());
+// **INDENT-OFF**
+ src = decltype(src){source, std::false_type()};
+// **INDENT-ON**
+ }
+
+ /** @brief Set the timer expiration time. */
+ void setTime(
+ const std::chrono::steady_clock::time_point& expires)
+ {
+ src.setTime(expires);
+ }
+
+ /** @brief Get the timer expiration time. */
+ auto getTime()
+ {
+ return src.getTime();
+ }
+
+ /** @brief Set the timer source enable state. */
+ void enable(int enable)
+ {
+ src.enable(enable);
+ }
+
+ /** @brief Query timer state. */
+ auto enabled()
+ {
+ return src.enabled();
+ }
+
+ private:
+ source::Source src;
+ std::unique_ptr<Callback> cb = nullptr;
+
+ static int callCallback(sd_event_source* s, uint64_t usec,
+ void* context)
+ {
+ source::Source source(s);
+ auto c = static_cast<Callback*>(context);
+ (*c)(source);
+
+ return 0;
+ }
+};
+} // namespace timer
+} // namespace event
+} // namespace sdevent