Commit | Line | Data |
---|---|---|
fca1d0f5 PP |
1 | |
2 | /* | |
3 | * SPDX-License-Identifier: MIT | |
4 | * | |
5 | * Copyright 2016 Jérémie Galarneau <jeremie.galarneau@efficios.com> | |
6 | * Copyright 2017-2023 Philippe Proulx <pproulx@efficios.com> | |
7 | */ | |
8 | ||
9 | #ifndef BABELTRACE_PLUGINS_UTILS_MUXER_UPSTREAM_MSG_ITER_HPP | |
10 | #define BABELTRACE_PLUGINS_UTILS_MUXER_UPSTREAM_MSG_ITER_HPP | |
11 | ||
12 | #include <memory> | |
13 | ||
14 | #include "common/assert.h" | |
15 | #include "cpp-common/bt2/message-array.hpp" | |
16 | #include "cpp-common/bt2/message-iterator.hpp" | |
17 | #include "cpp-common/bt2c/logging.hpp" | |
18 | #include "cpp-common/bt2s/optional.hpp" | |
19 | ||
20 | namespace bt2mux { | |
21 | ||
22 | /* | |
23 | * An instance of this wraps an upstream libbabeltrace2 message | |
24 | * iterator, keeping an internal array of receives messages, and making | |
25 | * the oldest one available (msg() method). | |
26 | */ | |
27 | class UpstreamMsgIter final | |
28 | { | |
29 | public: | |
30 | /* Unique pointer to upstream message iterator */ | |
31 | using UP = std::unique_ptr<UpstreamMsgIter>; | |
32 | ||
33 | /* Return type of reload() */ | |
34 | enum class ReloadStatus | |
35 | { | |
36 | MORE, | |
37 | NO_MORE, | |
38 | }; | |
39 | ||
40 | /* | |
41 | * Builds an upstream message iterator wrapper using the | |
42 | * libbabeltrace2 message iterator `msgIter`. | |
43 | * | |
44 | * This constructor doesn't immediately gets the next messages from | |
45 | * `*msgIter` (you always need to call reload() before you call | |
46 | * msg()), therefore it won't throw `bt2::Error` or `bt2::TryAgain`. | |
47 | */ | |
48 | explicit UpstreamMsgIter(bt2::MessageIterator::Shared msgIter, std::string portName, | |
49 | const bt2c::Logger& parentLogger); | |
50 | ||
51 | /* Some protection */ | |
52 | UpstreamMsgIter(const UpstreamMsgIter&) = delete; | |
53 | UpstreamMsgIter& operator=(const UpstreamMsgIter&) = delete; | |
54 | ||
55 | /* | |
56 | * Current message. | |
57 | * | |
58 | * Before you call this method: | |
59 | * | |
60 | * 1. If needed, you must call discard(). | |
61 | * | |
62 | * This is not the case immediately after construction and | |
63 | * immediately after seeking. | |
64 | * | |
65 | * 2. You must call reload() successfully (not ended). | |
66 | * | |
67 | * This is always the case. | |
68 | * | |
69 | * This makes it possible to build an `UpstreamMsgIter` instance | |
70 | * without libbabeltrace2 message iterator exceptions. | |
71 | */ | |
72 | bt2::ConstMessage msg() const noexcept | |
73 | { | |
74 | BT_ASSERT_DBG(_mMsgs.msgs && _mMsgs.index < _mMsgs.msgs->length()); | |
75 | return (*_mMsgs.msgs)[_mMsgs.index]; | |
76 | } | |
77 | ||
78 | /* | |
79 | * Timestamp, if any, of the current message. | |
80 | * | |
81 | * It must be valid to call msg() when you call this method. | |
82 | */ | |
83 | const bt2s::optional<std::int64_t> msgTs() const noexcept | |
84 | { | |
85 | return _mMsgTs; | |
86 | } | |
87 | ||
88 | /* | |
89 | * Discards the current message, making this upstream message | |
90 | * iterator ready for a reload (reload()). | |
91 | * | |
92 | * You may only call reload() or seekBeginning() after having called | |
93 | * this. | |
94 | */ | |
95 | void discard() noexcept | |
96 | { | |
97 | BT_ASSERT_DBG(_mMsgs.msgs && _mMsgs.index < _mMsgs.msgs->length()); | |
98 | BT_ASSERT_DBG(_mDiscardRequired); | |
99 | _mDiscardRequired = false; | |
100 | ++_mMsgs.index; | |
101 | ||
102 | if (_mMsgs.index == _mMsgs.msgs->length()) { | |
103 | _mMsgs.msgs.reset(); | |
104 | } | |
105 | } | |
106 | ||
107 | /* | |
108 | * Retrieves the next message, making it available afterwards | |
109 | * through the msg() method. | |
110 | * | |
111 | * You must have called discard() to discard the current message, if | |
112 | * any, before you call this method. | |
113 | * | |
114 | * This method may throw anything bt2::MessageIterator::next() may | |
115 | * throw. | |
116 | * | |
117 | * If this method returns `ReloadStatus::NO_MORE`, then the | |
118 | * underlying libbabeltrace2 message iterator is ended, meaning you | |
119 | * may not call msg(), msgTs(), or reload() again for this message | |
120 | * iterator until you successfully call seekBeginning(). | |
121 | */ | |
122 | ReloadStatus reload(); | |
123 | ||
124 | /* | |
125 | * Forwards to bt2::MessageIterator::canSeekBeginning(). | |
126 | */ | |
127 | bool canSeekBeginning(); | |
128 | ||
129 | /* | |
130 | * Forwards to bt2::MessageIterator::seekBeginning(). | |
131 | * | |
132 | * On success, you may call reload() afterwards. With any exception, | |
133 | * you must call this method again, successfully, before you may | |
134 | * call reload(). | |
135 | */ | |
136 | void seekBeginning(); | |
137 | ||
138 | /* | |
139 | * Forwards to bt2::MessageIterator::canSeekForward(). | |
140 | */ | |
141 | bool canSeekForward() const noexcept; | |
142 | ||
143 | /* | |
144 | * Name of the input port on which the libbabeltrace2 message | |
145 | * iterator was created. | |
146 | */ | |
147 | const std::string& portName() const noexcept | |
148 | { | |
149 | return _mPortName; | |
150 | } | |
151 | ||
152 | private: | |
153 | /* | |
154 | * Tries to get new messages into `_mMsgs.msgs`. | |
155 | */ | |
156 | void _tryGetNewMsgs(); | |
157 | ||
158 | /* Actual upstream message iterator */ | |
159 | bt2::MessageIterator::Shared _mMsgIter; | |
160 | ||
161 | /* | |
162 | * Currently contained messages. | |
163 | * | |
164 | * `index` is the index of the current message (msg()/msgTs()) | |
165 | * within `msgs`. | |
166 | */ | |
167 | struct | |
168 | { | |
169 | bt2s::optional<bt2::ConstMessageArray> msgs; | |
170 | std::size_t index; | |
171 | } _mMsgs; | |
172 | ||
173 | /* Timestamp of the current message, if any */ | |
174 | bt2s::optional<std::int64_t> _mMsgTs; | |
175 | ||
176 | /* | |
177 | * Only relevant in debug mode: true if a call to discard() is | |
178 | * required before calling reload(). | |
179 | */ | |
180 | bool _mDiscardRequired = false; | |
181 | ||
182 | bt2c::Logger _mLogger; | |
183 | std::string _mPortName; | |
184 | }; | |
185 | ||
186 | } /* namespace bt2mux */ | |
187 | ||
188 | #endif /* BABELTRACE_PLUGINS_UTILS_MUXER_UPSTREAM_MSG_ITER_HPP */ |