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/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