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