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