src/plugins/utils/muxer/msg-iter.hpp

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   5  * Copyright 2017-2023 Philippe Proulx <pproulx@efficios.com>
   6  */
   7
   8 #ifndef BABELTRACE_PLUGINS_UTILS_MUXER_MSG_ITER_HPP
   9 #define BABELTRACE_PLUGINS_UTILS_MUXER_MSG_ITER_HPP
  10
  11 #include <vector>
  12
  13 #include "cpp-common/bt2/component-class-dev.hpp"
  14 #include "cpp-common/bt2/optional-borrowed-object.hpp"
  15 #include "cpp-common/bt2/self-message-iterator-configuration.hpp"
  16 #include "cpp-common/bt2c/prio-heap.hpp"
  17 #include "cpp-common/bt2c/uuid.hpp"
  18 #include "cpp-common/bt2s/optional.hpp"
  19
  20 #include "upstream-msg-iter.hpp"
  21
  22 namespace bt2mux {
  23
  24 class Comp;
  25
  26 class MsgIter final : public bt2::UserMessageIterator<MsgIter, Comp>
  27 {
  28     friend bt2::UserMessageIterator<MsgIter, Comp>;
  29
  30 private:
  31     /* Clock class nature expectation */
  32     enum class _ClkClsExpectation
  33     {
  34         ANY,
  35         NONE,
  36         ORIG_IS_UNIX_EPOCH,
  37         ORIG_ISNT_UNIX_EPOCH_AND_SPEC_UUID,
  38         ORIG_ISNT_UNIX_EPOCH_AND_NO_UUID,
  39     };
  40
  41     /* Comparator for `_mHeap` with its own logger */
  42     class _HeapComparator final
  43     {
  44     public:
  45         explicit _HeapComparator(const bt2c::Logger& logger);
  46
  47         bool operator()(const UpstreamMsgIter *upstreamMsgIterA,
  48                         const UpstreamMsgIter *upstreamMsgIterB) const noexcept;
  49
  50     private:
  51         bt2c::Logger _mLogger;
  52     };
  53
  54 public:
  55     explicit MsgIter(bt2::SelfMessageIterator selfMsgIter,
  56                      bt2::SelfMessageIteratorConfiguration config,
  57                      bt2::SelfComponentOutputPort selfPort);
  58
  59 private:
  60     bool _canSeekBeginning();
  61     void _seekBeginning();
  62     void _next(bt2::ConstMessageArray& msgs);
  63
  64     /*
  65      * Makes sure `_mUpstreamMsgItersToReload` is empty so that `_mHeap`
  66      * is ready for the next message selection.
  67      *
  68      * This may throw whatever UpstreamMsgIter::reload() may throw.
  69      */
  70     void _ensureFullHeap();
  71
  72     /*
  73      * Validates the clock class of the received message `msg`, setting
  74      * the expectation if this is the first one.
  75      *
  76      * Throws `bt2::Error` on error.
  77      */
  78     void _validateMsgClkCls(bt2::ConstMessage msg);
  79
  80     /*
  81      * Sets the clock class expectation (`_mClkClsExpectation` and
  82      * `_mExpectedClkClsUuid`) according to `clkCls`.
  83      */
  84     void _setClkClsExpectation(bt2::OptionalBorrowedObject<bt2::ConstClockClass> clkCls) noexcept;
  85
  86     /*
  87      * Checks that `clkCls` meets the current clock class expectation,
  88      * throwing if it doesn't.
  89      */
  90     void _makeSureClkClsIsExpected(bt2::ConstMessage msg,
  91                                    bt2::OptionalBorrowedObject<bt2::ConstClockClass> clkCls) const;
  92
  93     /*
  94      * Container of all the upstream message iterators.
  95      *
  96      * The only purpose of this is to own them; where they are below
  97      * indicates their state.
  98      */
  99     std::vector<UpstreamMsgIter::UP> _mUpstreamMsgIters;
 100
 101     /*
 102      * Heap of ready-to-use upstream message iterators (pointers to
 103      * owned objects in `_mUpstreamMsgIters` above).
 104      */
 105     bt2c::PrioHeap<UpstreamMsgIter *, _HeapComparator> _mHeap;
 106
 107     /*
 108      * Current upstream message iterators to reload, on which we must
 109      * call reload() before moving them to `_mHeap` or to
 110      * `_mEndedUpstreamMsgIters`.
 111      *
 112      * Using `std::vector` instead of some linked list because the
 113      * typical scenario is to add a single one and then remove it
 114      * shortly after.
 115      */
 116     std::vector<UpstreamMsgIter *> _mUpstreamMsgItersToReload;
 117
 118     /*
 119      * Which kind of clock class to expect from any incoming message.
 120      *
 121      * The very first received message determines this for all the
 122      * following.
 123      *
 124      * For `ORIG_ISNT_UNIX_EPOCH_AND_SPEC_UUID`, `*_mExpectedClkClsUuid`
 125      * is the expected specific UUID.
 126      */
 127     _ClkClsExpectation _mClkClsExpectation = _ClkClsExpectation::ANY;
 128     bt2s::optional<bt2c::Uuid> _mExpectedClkClsUuid;
 129 };
 130
 131 } /* namespace bt2mux */
 132
 133 #endif /* BABELTRACE_PLUGINS_UTILS_MUXER_MSG_ITER_HPP */