sessiond: add tracer-agnostic trace hierarchy classes

[lttng-tools.git] / src / bin / lttng-sessiond / trace-class.hpp

diff --git a/src/bin/lttng-sessiond/trace-class.hpp b/src/bin/lttng-sessiond/trace-class.hpp
new file mode 100644 (file)
index 0000000..0874998
--- /dev/null
+++ b/src/bin/lttng-sessiond/trace-class.hpp
@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2022 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#ifndef LTTNG_TRACE_CLASS_H
+#define LTTNG_TRACE_CLASS_H
+
+#include <common/uuid.hpp>
+
+namespace lttng {
+namespace sessiond {
+namespace trace {
+
+class clock_class;
+class stream_class;
+class event_class;
+class trace_class_visitor;
+
+enum class byte_order {
+       BIG_ENDIAN_,
+       LITTLE_ENDIAN_,
+};
+
+struct abi {
+       unsigned int bits_per_long;
+       unsigned int long_alignment;
+       unsigned int uint8_t_alignment;
+       unsigned int uint16_t_alignment;
+       unsigned int uint32_t_alignment;
+       unsigned int uint64_t_alignment;
+       enum byte_order byte_order;
+};
+
+template <class ValueType>
+class environment_field {
+public:
+       environment_field(const char *in_name, const ValueType& in_value) :
+               name(in_name), value(in_value)
+       {
+       }
+
+       const char * const name;
+       const ValueType& value;
+};
+
+class trace_class {
+public:
+       /*
+        * Derived classes must implement the _accept_on_*()
+        * to continue the traversal to the trace class' children.
+        */
+       virtual void accept(trace_class_visitor& trace_class_visitor) const;
+
+       virtual ~trace_class() = default;
+
+       const struct abi abi;
+       const lttng_uuid uuid;
+
+protected:
+       trace_class(const struct abi& abi, const lttng_uuid& trace_uuid);
+       virtual void _accept_on_clock_classes(trace_class_visitor& trace_class_visitor) const = 0;
+       virtual void _visit_environment(trace_class_visitor& trace_class_visitor) const = 0;
+       virtual void _accept_on_stream_classes(trace_class_visitor& trace_class_visitor) const = 0;
+};
+
+class trace_class_visitor {
+public:
+       using cuptr = std::unique_ptr<trace_class_visitor>;
+
+       virtual ~trace_class_visitor() = default;
+
+       /* trace class visitor interface. */
+       virtual void visit(const lttng::sessiond::trace::trace_class& trace_class) = 0;
+
+       /* clock class visitor interface. */
+       virtual void visit(const lttng::sessiond::trace::clock_class& clock_class) = 0;
+
+       /* environment visitor interface. */
+       virtual void environment_begin() = 0;
+       virtual void visit(const environment_field<int64_t>& field) = 0;
+       virtual void visit(const environment_field<const char *>& field) = 0;
+       void visit(const environment_field<std::string>& field);
+       virtual void environment_end() = 0;
+
+       /* stream class visitor interface. */
+       virtual void visit(const lttng::sessiond::trace::stream_class& stream_class) = 0;
+
+       /* event class visitor interface. */
+       virtual void visit(const lttng::sessiond::trace::event_class& event_class) = 0;
+};
+
+} /* namespace trace */
+} /* namespace sessiond */
+} /* namespace lttng */
+
+#endif /* LTTNG_TRACE_CLASS_H */