src/bin/lttng-sessiond/trace-class.hpp

   1 /*
   2  * Copyright (C) 2022 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   3  *
   4  * SPDX-License-Identifier: GPL-2.0-only
   5  *
   6  */
   7
   8 #ifndef LTTNG_TRACE_CLASS_H
   9 #define LTTNG_TRACE_CLASS_H
  10
  11 #include <common/uuid.hpp>
  12
  13 namespace lttng {
  14 namespace sessiond {
  15 namespace trace {
  16
  17 class clock_class;
  18 class stream_class;
  19 class event_class;
  20 class trace_class_visitor;
  21
  22 enum class byte_order {
  23         BIG_ENDIAN_,
  24         LITTLE_ENDIAN_,
  25 };
  26
  27 struct abi {
  28         unsigned int bits_per_long;
  29         unsigned int long_alignment;
  30         unsigned int uint8_t_alignment;
  31         unsigned int uint16_t_alignment;
  32         unsigned int uint32_t_alignment;
  33         unsigned int uint64_t_alignment;
  34         enum byte_order byte_order;
  35 };
  36
  37 template <class ValueType>
  38 class environment_field {
  39 public:
  40         environment_field(const char *in_name, const ValueType& in_value) :
  41                 name(in_name), value(in_value)
  42         {
  43         }
  44
  45         const char * const name;
  46         const ValueType& value;
  47 };
  48
  49 class trace_class {
  50 public:
  51         /*
  52          * Derived classes must implement the _accept_on_*()
  53          * to continue the traversal to the trace class' children.
  54          */
  55         virtual void accept(trace_class_visitor& trace_class_visitor) const;
  56
  57         virtual ~trace_class() = default;
  58
  59         const struct abi abi;
  60         const lttng_uuid uuid;
  61
  62 protected:
  63         trace_class(const struct abi& abi, const lttng_uuid& trace_uuid);
  64         virtual void _accept_on_clock_classes(trace_class_visitor& trace_class_visitor) const = 0;
  65         virtual void _visit_environment(trace_class_visitor& trace_class_visitor) const = 0;
  66         virtual void _accept_on_stream_classes(trace_class_visitor& trace_class_visitor) const = 0;
  67 };
  68
  69 class trace_class_visitor {
  70 public:
  71         using cuptr = std::unique_ptr<trace_class_visitor>;
  72
  73         virtual ~trace_class_visitor() = default;
  74
  75         /* trace class visitor interface. */
  76         virtual void visit(const lttng::sessiond::trace::trace_class& trace_class) = 0;
  77
  78         /* clock class visitor interface. */
  79         virtual void visit(const lttng::sessiond::trace::clock_class& clock_class) = 0;
  80
  81         /* environment visitor interface. */
  82         virtual void environment_begin() = 0;
  83         virtual void visit(const environment_field<int64_t>& field) = 0;
  84         virtual void visit(const environment_field<const char *>& field) = 0;
  85         void visit(const environment_field<std::string>& field);
  86         virtual void environment_end() = 0;
  87
  88         /* stream class visitor interface. */
  89         virtual void visit(const lttng::sessiond::trace::stream_class& stream_class) = 0;
  90
  91         /* event class visitor interface. */
  92         virtual void visit(const lttng::sessiond::trace::event_class& event_class) = 0;
  93 };
  94
  95 } /* namespace trace */
  96 } /* namespace sessiond */
  97 } /* namespace lttng */
  98
  99 #endif /* LTTNG_TRACE_CLASS_H */