You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@mesos.apache.org by gi...@apache.org on 2018/07/15 23:22:16 UTC
[07/10] mesos-site git commit: Updated the website built from mesos
SHA: b1eafc0.
http://git-wip-us.apache.org/repos/asf/mesos-site/blob/1ce9f4ab/content/api/latest/c++/event__queue_8hpp_source.html
----------------------------------------------------------------------
diff --git a/content/api/latest/c++/event__queue_8hpp_source.html b/content/api/latest/c++/event__queue_8hpp_source.html
index 90bf553..3a5863e 100644
--- a/content/api/latest/c++/event__queue_8hpp_source.html
+++ b/content/api/latest/c++/event__queue_8hpp_source.html
@@ -52,7 +52,8 @@
<div class="title">event_queue.hpp</div> </div>
</div><!--header-->
<div class="contents">
-<a href="event__queue_8hpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span> <span class="comment">// Licensed under the Apache License, Version 2.0 (the "License");</span></div><div class="line"><a name="l00002"></a><span class="lineno"> 2</span> <span class="comment">// you may not use this file except in compliance with the License.</span></div><div class="line"><a name="l00003"></a><span class="lineno"> 3</span> <span class="comment">// You may obtain a copy of the License at</span></div><div class="line"><a name="l00004"></a><span class="lineno"> 4</span> <span class="comment">//</span></div><div class="line"><a name="l00005"></a><span class="lineno"> 5</span> <span class="comment">// http://www.apache.org/licenses/LICENSE-2.0</span></div><div class="line"><a name="l00006"></a><span class="lineno"> 6</span> <span class="comment">
//</span></div><div class="line"><a name="l00007"></a><span class="lineno"> 7</span> <span class="comment">// Unless required by applicable law or agreed to in writing, software</span></div><div class="line"><a name="l00008"></a><span class="lineno"> 8</span> <span class="comment">// distributed under the License is distributed on an "AS IS" BASIS,</span></div><div class="line"><a name="l00009"></a><span class="lineno"> 9</span> <span class="comment">// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span></div><div class="line"><a name="l00010"></a><span class="lineno"> 10</span> <span class="comment">// See the License for the specific language governing permissions and</span></div><div class="line"><a name="l00011"></a><span class="lineno"> 11</span> <span class="comment">// limitations under the License</span></div><div class="line"><a name="l00012"></a><span class="lineno"> 12</span> </div><div cla
ss="line"><a name="l00013"></a><span class="lineno"> 13</span> <span class="preprocessor">#ifndef __PROCESS_EVENT_QUEUE_HPP__</span></div><div class="line"><a name="l00014"></a><span class="lineno"> 14</span> <span class="preprocessor">#define __PROCESS_EVENT_QUEUE_HPP__</span></div><div class="line"><a name="l00015"></a><span class="lineno"> 15</span> </div><div class="line"><a name="l00016"></a><span class="lineno"> 16</span> <span class="preprocessor">#include <deque></span></div><div class="line"><a name="l00017"></a><span class="lineno"> 17</span> <span class="preprocessor">#include <mutex></span></div><div class="line"><a name="l00018"></a><span class="lineno"> 18</span> <span class="preprocessor">#include <string></span></div><div class="line"><a name="l00019"></a><span class="lineno"> 19</span> </div><div class="line"><a name="l00020"></a><span class="lineno"> 20</span> <span class="preprocessor">#ifde
f LOCK_FREE_EVENT_QUEUE</span></div><div class="line"><a name="l00021"></a><span class="lineno"> 21</span> <span class="preprocessor">#include <concurrentqueue.h></span></div><div class="line"><a name="l00022"></a><span class="lineno"> 22</span> <span class="preprocessor">#endif // LOCK_FREE_EVENT_QUEUE</span></div><div class="line"><a name="l00023"></a><span class="lineno"> 23</span> </div><div class="line"><a name="l00024"></a><span class="lineno"> 24</span> <span class="preprocessor">#include <<a class="code" href="event_8hpp.html">process/event.hpp</a>></span></div><div class="line"><a name="l00025"></a><span class="lineno"> 25</span> <span class="preprocessor">#include <<a class="code" href="3rdparty_2libprocess_2include_2process_2http_8hpp.html">process/http.hpp</a>></span></div><div class="line"><a name="l00026"></a><span class="lineno"> 26</span> </div><div class="line"><a name="l00027"></a><span class="lineno"> 2
7</span> <span class="preprocessor">#include <<a class="code" href="json_8hpp.html">stout/json.hpp</a>></span></div><div class="line"><a name="l00028"></a><span class="lineno"> 28</span> <span class="preprocessor">#include <<a class="code" href="stringify_8hpp.html">stout/stringify.hpp</a>></span></div><div class="line"><a name="l00029"></a><span class="lineno"> 29</span> <span class="preprocessor">#include <<a class="code" href="synchronized_8hpp.html">stout/synchronized.hpp</a>></span></div><div class="line"><a name="l00030"></a><span class="lineno"> 30</span> </div><div class="line"><a name="l00031"></a><span class="lineno"> 31</span> <span class="keyword">namespace </span><a class="code" href="namespaceprocess.html">process</a> {</div><div class="line"><a name="l00032"></a><span class="lineno"> 32</span> </div><div class="line"><a name="l00033"></a><span class="lineno"> 33</span> <span class="comment">// A _multipl
e_ producer (MP) _single_ consumer (SC) event queue for a</span></div><div class="line"><a name="l00034"></a><span class="lineno"> 34</span> <span class="comment">// process. Note that we don't _enforce_ the MP/SC semantics during</span></div><div class="line"><a name="l00035"></a><span class="lineno"> 35</span> <span class="comment">// runtime but we have explicitly separated out the `Producer`</span></div><div class="line"><a name="l00036"></a><span class="lineno"> 36</span> <span class="comment">// interface and the `Consumer` interface in order to help avoid</span></div><div class="line"><a name="l00037"></a><span class="lineno"> 37</span> <span class="comment">// incorrect usage.</span></div><div class="line"><a name="l00038"></a><span class="lineno"> 38</span> <span class="comment">//</span></div><div class="line"><a name="l00039"></a><span class="lineno"> 39</span> <span class="comment">// Notable semantics:</span></div><div class
="line"><a name="l00040"></a><span class="lineno"> 40</span> <span class="comment">//</span></div><div class="line"><a name="l00041"></a><span class="lineno"> 41</span> <span class="comment">// * Consumers _must_ call `empty()` before calling</span></div><div class="line"><a name="l00042"></a><span class="lineno"> 42</span> <span class="comment">// `dequeue()`. Failing to do so may result in undefined behavior.</span></div><div class="line"><a name="l00043"></a><span class="lineno"> 43</span> <span class="comment">//</span></div><div class="line"><a name="l00044"></a><span class="lineno"> 44</span> <span class="comment">// * After a consumer calls `decomission()` they _must_ not call any</span></div><div class="line"><a name="l00045"></a><span class="lineno"> 45</span> <span class="comment">// thing else (not even `empty()` and especially not</span></div><div class="line"><a name="l00046"></a><span class="lineno"> 46</span>
0;<span class="comment">// `dequeue()`). Doing so is undefined behavior.</span></div><div class="line"><a name="l00047"></a><span class="lineno"> 47</span> <span class="comment">//</span></div><div class="line"><a name="l00048"></a><span class="lineno"> 48</span> <span class="comment">// Notes on the lock-free implementation:</span></div><div class="line"><a name="l00049"></a><span class="lineno"> 49</span> <span class="comment">//</span></div><div class="line"><a name="l00050"></a><span class="lineno"> 50</span> <span class="comment">// The SC requirement is necessary for the lock-free implementation</span></div><div class="line"><a name="l00051"></a><span class="lineno"> 51</span> <span class="comment">// because the underlying queue does not provide linearizability which</span></div><div class="line"><a name="l00052"></a><span class="lineno"> 52</span> <span class="comment">// means events can be dequeued "out of order". Usu
ally this is not a</span></div><div class="line"><a name="l00053"></a><span class="lineno"> 53</span> <span class="comment">// problem, after all, in most circumstances we won't know the order</span></div><div class="line"><a name="l00054"></a><span class="lineno"> 54</span> <span class="comment">// in which events might be enqueued in the first place. However, this</span></div><div class="line"><a name="l00055"></a><span class="lineno"> 55</span> <span class="comment">// can be a very bad problem if a single process attempts to enqueue</span></div><div class="line"><a name="l00056"></a><span class="lineno"> 56</span> <span class="comment">// two events in a different process AND THOSE EVENTS ARE</span></div><div class="line"><a name="l00057"></a><span class="lineno"> 57</span> <span class="comment">// REORDERED. To ensure this will never be the case we give every</span></div><div class="line"><a name="l00058"></a><span class="lineno"> 58</sp
an> <span class="comment">// event a sequence number. That way an event from the same process</span></div><div class="line"><a name="l00059"></a><span class="lineno"> 59</span> <span class="comment">// will always have a happens-before relationship with respect to the</span></div><div class="line"><a name="l00060"></a><span class="lineno"> 60</span> <span class="comment">// events that they enqueue because they'll have distinct sequence</span></div><div class="line"><a name="l00061"></a><span class="lineno"> 61</span> <span class="comment">// numbers.</span></div><div class="line"><a name="l00062"></a><span class="lineno"> 62</span> <span class="comment">//</span></div><div class="line"><a name="l00063"></a><span class="lineno"> 63</span> <span class="comment">// This makes the consumer implementation more difficult because the</span></div><div class="line"><a name="l00064"></a><span class="lineno"> 64</span> <span class="comment">/
/ consumer might need to "reorder" events as it reads them out. To do</span></div><div class="line"><a name="l00065"></a><span class="lineno"> 65</span> <span class="comment">// this efficiently we require only a single consumer, which fits well</span></div><div class="line"><a name="l00066"></a><span class="lineno"> 66</span> <span class="comment">// into the actor model because there will only ever be a single</span></div><div class="line"><a name="l00067"></a><span class="lineno"> 67</span> <span class="comment">// thread consuming an actors events at a time.</span></div><div class="line"><a name="l00068"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue.html"> 68</a></span> <span class="keyword">class </span><a class="code" href="classprocess_1_1EventQueue.html">EventQueue</a></div><div class="line"><a name="l00069"></a><span class="lineno"> 69</span> {</div><div class="line"><a name="l00070"></a><span class="l
ineno"> 70</span> <span class="keyword">public</span>:</div><div class="line"><a name="l00071"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue.html#ad2d51d8a2a80f473de0bcf2e08e48d90"> 71</a></span>  <a class="code" href="classprocess_1_1EventQueue.html#ad2d51d8a2a80f473de0bcf2e08e48d90">EventQueue</a>() : <a class="code" href="classprocess_1_1EventQueue.html#aa95046266e731af49ccfb9d689cb1eca">producer</a>(this), <a class="code" href="classprocess_1_1EventQueue.html#a73f44b10f6d09ead6bdf3ab11cba4d06">consumer</a>(this) {}</div><div class="line"><a name="l00072"></a><span class="lineno"> 72</span> </div><div class="line"><a name="l00073"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Producer.html"> 73</a></span>  <span class="keyword">class </span><a class="code" href="classprocess_1_1EventQueue_1_1Producer.html">Producer</a></div><div class="line"><a name="l00074"></a><span class="lineno"> 74</sp
an>  {</div><div class="line"><a name="l00075"></a><span class="lineno"> 75</span>  <span class="keyword">public</span>:</div><div class="line"><a name="l00076"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Producer.html#a30a6a96aad51b429e48eba775a4a002d"> 76</a></span>  <span class="keywordtype">void</span> <a class="code" href="classprocess_1_1EventQueue_1_1Producer.html#a30a6a96aad51b429e48eba775a4a002d">enqueue</a>(<a class="code" href="structprocess_1_1Event.html">Event</a>* event) { queue->enqueue(event); }</div><div class="line"><a name="l00077"></a><span class="lineno"> 77</span> </div><div class="line"><a name="l00078"></a><span class="lineno"> 78</span>  <span class="keyword">private</span>:</div><div class="line"><a name="l00079"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Producer.html#a3b1787a64e5e97ce075c05a58303d58c"> 79</a></span>  <span class="keyword"
>friend</span> <span class="keyword">class </span><a class="code" href="classprocess_1_1EventQueue.html">EventQueue</a>;</div><div class="line"><a name="l00080"></a><span class="lineno"> 80</span> </div><div class="line"><a name="l00081"></a><span class="lineno"> 81</span>  <a class="code" href="classprocess_1_1EventQueue_1_1Producer.html">Producer</a>(<a class="code" href="classprocess_1_1EventQueue.html">EventQueue</a>* queue) : queue(queue) {}</div><div class="line"><a name="l00082"></a><span class="lineno"> 82</span> </div><div class="line"><a name="l00083"></a><span class="lineno"> 83</span>  <a class="code" href="classprocess_1_1EventQueue.html">EventQueue</a>* queue;</div><div class="line"><a name="l00084"></a><span class="lineno"> 84</span>  } <a class="code" href="classprocess_1_1EventQueue.html#aa95046266e731af49ccfb9d689cb1eca">producer</a>;</div><div class="line"><a name="l00085"></a><span class="lineno"> 85</span> </div><
div class="line"><a name="l00086"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Consumer.html"> 86</a></span>  <span class="keyword">class </span><a class="code" href="classprocess_1_1EventQueue_1_1Consumer.html">Consumer</a></div><div class="line"><a name="l00087"></a><span class="lineno"> 87</span>  {</div><div class="line"><a name="l00088"></a><span class="lineno"> 88</span>  <span class="keyword">public</span>:</div><div class="line"><a name="l00089"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Consumer.html#a0947a38c4933c27cc6b422ce9171a400"> 89</a></span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* <a class="code" href="classprocess_1_1EventQueue_1_1Consumer.html#a0947a38c4933c27cc6b422ce9171a400">dequeue</a>() { <span class="keywordflow">return</span> queue->dequeue(); }</div><div class="line"><a name="l00090"></a><span class="lineno"><a class="line" href="cl
assprocess_1_1EventQueue_1_1Consumer.html#aa42de8d3e7ba7c56362a36efa773790d"> 90</a></span>  <span class="keywordtype">bool</span> <a class="code" href="classprocess_1_1EventQueue_1_1Consumer.html#aa42de8d3e7ba7c56362a36efa773790d">empty</a>() { <span class="keywordflow">return</span> queue->empty(); }</div><div class="line"><a name="l00091"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Consumer.html#a7976eeb2b9ff88c5f03551c63764a162"> 91</a></span>  <span class="keywordtype">void</span> <a class="code" href="classprocess_1_1EventQueue_1_1Consumer.html#a7976eeb2b9ff88c5f03551c63764a162">decomission</a>() { queue->decomission(); }</div><div class="line"><a name="l00092"></a><span class="lineno"> 92</span>  <span class="keyword">template</span> <<span class="keyword">typename</span> T></div><div class="line"><a name="l00093"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Consumer.htm
l#a8d998919af90a6146e6745a1217be3ce"> 93</a></span>  <span class="keywordtype">size_t</span> <a class="code" href="classprocess_1_1EventQueue_1_1Consumer.html#a8d998919af90a6146e6745a1217be3ce">count</a>() { <span class="keywordflow">return</span> queue->count<T>(); }</div><div class="line"><a name="l00094"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Consumer.html#a307aaa062d7b5feee064e0361a3cb166"> 94</a></span>  <span class="keyword">operator</span> <a class="code" href="structJSON_1_1Array.html">JSON::Array</a>() { <span class="keywordflow">return</span> queue->operator <a class="code" href="structJSON_1_1Array.html">JSON::Array</a>(); }</div><div class="line"><a name="l00095"></a><span class="lineno"> 95</span> </div><div class="line"><a name="l00096"></a><span class="lineno"> 96</span>  <span class="keyword">private</span>:</div><div class="line"><a name="l00097"></a><span class="lineno"><a class="l
ine" href="classprocess_1_1EventQueue_1_1Consumer.html#a3b1787a64e5e97ce075c05a58303d58c"> 97</a></span>  <span class="keyword">friend</span> <span class="keyword">class </span><a class="code" href="classprocess_1_1EventQueue.html">EventQueue</a>;</div><div class="line"><a name="l00098"></a><span class="lineno"> 98</span> </div><div class="line"><a name="l00099"></a><span class="lineno"> 99</span>  <a class="code" href="classprocess_1_1EventQueue.html#a11390aaa07bced511a5b7fe4c94e97fd">Consumer</a>(<a class="code" href="classprocess_1_1EventQueue.html">EventQueue</a>* queue) : queue(queue) {}</div><div class="line"><a name="l00100"></a><span class="lineno"> 100</span> </div><div class="line"><a name="l00101"></a><span class="lineno"> 101</span>  <a class="code" href="classprocess_1_1EventQueue.html">EventQueue</a>* queue;</div><div class="line"><a name="l00102"></a><span class="lineno"> 102</span>  } <a class="code" href="classprocess
_1_1EventQueue.html#a73f44b10f6d09ead6bdf3ab11cba4d06">consumer</a>;</div><div class="line"><a name="l00103"></a><span class="lineno"> 103</span> </div><div class="line"><a name="l00104"></a><span class="lineno"> 104</span> <span class="keyword">private</span>:</div><div class="line"><a name="l00105"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue.html#aaf00b363e56ec3a72a6f775a3814d6a0"> 105</a></span>  <span class="keyword">friend</span> <span class="keyword">class </span><a class="code" href="classprocess_1_1EventQueue_1_1Producer.html">Producer</a>;</div><div class="line"><a name="l00106"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue.html#a11390aaa07bced511a5b7fe4c94e97fd"> 106</a></span>  <span class="keyword">friend</span> <span class="keyword">class </span><a class="code" href="classprocess_1_1EventQueue_1_1Consumer.html">Consumer</a>;</div><div class="line"><a name="l00107"></a><span class="lineno
"> 107</span> </div><div class="line"><a name="l00108"></a><span class="lineno"> 108</span> <span class="preprocessor">#ifndef LOCK_FREE_EVENT_QUEUE</span></div><div class="line"><a name="l00109"></a><span class="lineno"> 109</span>  <span class="keywordtype">void</span> <a class="code" href="classprocess_1_1EventQueue_1_1Producer.html#a30a6a96aad51b429e48eba775a4a002d">enqueue</a>(<a class="code" href="structprocess_1_1Event.html">Event</a>* event)</div><div class="line"><a name="l00110"></a><span class="lineno"> 110</span>  {</div><div class="line"><a name="l00111"></a><span class="lineno"> 111</span>  <span class="keywordtype">bool</span> enqueued = <span class="keyword">false</span>;</div><div class="line"><a name="l00112"></a><span class="lineno"> 112</span>  <span class="keyword">synchronized</span> (mutex) {</div><div class="line"><a name="l00113"></a><span class="lineno"> 113</span>  <span class="keywordflow">if</span> (
comissioned) {</div><div class="line"><a name="l00114"></a><span class="lineno"> 114</span>  events.push_back(event);</div><div class="line"><a name="l00115"></a><span class="lineno"> 115</span>  enqueued = <span class="keyword">true</span>;</div><div class="line"><a name="l00116"></a><span class="lineno"> 116</span>  }</div><div class="line"><a name="l00117"></a><span class="lineno"> 117</span>  }</div><div class="line"><a name="l00118"></a><span class="lineno"> 118</span> </div><div class="line"><a name="l00119"></a><span class="lineno"> 119</span>  <span class="keywordflow">if</span> (!enqueued) {</div><div class="line"><a name="l00120"></a><span class="lineno"> 120</span>  <span class="keyword">delete</span> event;</div><div class="line"><a name="l00121"></a><span class="lineno"> 121</span>  }</div><div class="line"><a name="l00122"></a><span class="lineno"> 122</span>  }</div><div class="lin
e"><a name="l00123"></a><span class="lineno"> 123</span> </div><div class="line"><a name="l00124"></a><span class="lineno"> 124</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* dequeue()</div><div class="line"><a name="l00125"></a><span class="lineno"> 125</span>  {</div><div class="line"><a name="l00126"></a><span class="lineno"> 126</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* <span class="keyword">event</span> = <span class="keyword">nullptr</span>;</div><div class="line"><a name="l00127"></a><span class="lineno"> 127</span> </div><div class="line"><a name="l00128"></a><span class="lineno"> 128</span>  <span class="keyword">synchronized</span> (mutex) {</div><div class="line"><a name="l00129"></a><span class="lineno"> 129</span>  <span class="keywordflow">if</span> (events.size() > 0) {</div><div class="line"><a name="l00130"></a><span class="lineno"> 130</span>  <
a class="code" href="structprocess_1_1Event.html">Event</a>* <span class="keyword">event</span> = events.front();</div><div class="line"><a name="l00131"></a><span class="lineno"> 131</span>  events.pop_front();</div><div class="line"><a name="l00132"></a><span class="lineno"> 132</span>  <span class="keywordflow">return</span> event;</div><div class="line"><a name="l00133"></a><span class="lineno"> 133</span>  }</div><div class="line"><a name="l00134"></a><span class="lineno"> 134</span>  }</div><div class="line"><a name="l00135"></a><span class="lineno"> 135</span> </div><div class="line"><a name="l00136"></a><span class="lineno"> 136</span>  <span class="comment">// Semantics are the consumer _must_ call `empty()` before calling</span></div><div class="line"><a name="l00137"></a><span class="lineno"> 137</span>  <span class="comment">// `dequeue()` which means an event must be present.</span></div><div class="l
ine"><a name="l00138"></a><span class="lineno"> 138</span>  <span class="keywordflow">return</span> CHECK_NOTNULL(event);</div><div class="line"><a name="l00139"></a><span class="lineno"> 139</span>  }</div><div class="line"><a name="l00140"></a><span class="lineno"> 140</span> </div><div class="line"><a name="l00141"></a><span class="lineno"> 141</span>  <span class="keywordtype">bool</span> empty()</div><div class="line"><a name="l00142"></a><span class="lineno"> 142</span>  {</div><div class="line"><a name="l00143"></a><span class="lineno"> 143</span>  <span class="keyword">synchronized</span> (mutex) {</div><div class="line"><a name="l00144"></a><span class="lineno"> 144</span>  <span class="keywordflow">return</span> events.size() == 0;</div><div class="line"><a name="l00145"></a><span class="lineno"> 145</span>  }</div><div class="line"><a name="l00146"></a><span class="lineno"> 146</span>  }</div><div cla
ss="line"><a name="l00147"></a><span class="lineno"> 147</span> </div><div class="line"><a name="l00148"></a><span class="lineno"> 148</span>  <span class="keywordtype">void</span> decomission()</div><div class="line"><a name="l00149"></a><span class="lineno"> 149</span>  {</div><div class="line"><a name="l00150"></a><span class="lineno"> 150</span>  <span class="keyword">synchronized</span> (mutex) {</div><div class="line"><a name="l00151"></a><span class="lineno"> 151</span>  comissioned = <span class="keyword">false</span>;</div><div class="line"><a name="l00152"></a><span class="lineno"> 152</span>  <span class="keywordflow">while</span> (!events.empty()) {</div><div class="line"><a name="l00153"></a><span class="lineno"> 153</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* <span class="keyword">event</span> = events.front();</div><div class="line"><a name="l00154"></a><span class="lineno"> 154
</span>  events.pop_front();</div><div class="line"><a name="l00155"></a><span class="lineno"> 155</span>  <span class="keyword">delete</span> event;</div><div class="line"><a name="l00156"></a><span class="lineno"> 156</span>  }</div><div class="line"><a name="l00157"></a><span class="lineno"> 157</span>  }</div><div class="line"><a name="l00158"></a><span class="lineno"> 158</span>  }</div><div class="line"><a name="l00159"></a><span class="lineno"> 159</span> </div><div class="line"><a name="l00160"></a><span class="lineno"> 160</span>  <span class="keyword">template</span> <<span class="keyword">typename</span> T></div><div class="line"><a name="l00161"></a><span class="lineno"> 161</span>  <span class="keywordtype">size_t</span> count()</div><div class="line"><a name="l00162"></a><span class="lineno"> 162</span>  {</div><div class="line"><a name="l00163"></a><span class="lineno"> 163</span>
60; <span class="keyword">synchronized</span> (mutex) {</div><div class="line"><a name="l00164"></a><span class="lineno"> 164</span>  <span class="keywordflow">return</span> std::count_if(</div><div class="line"><a name="l00165"></a><span class="lineno"> 165</span>  events.begin(),</div><div class="line"><a name="l00166"></a><span class="lineno"> 166</span>  events.end(),</div><div class="line"><a name="l00167"></a><span class="lineno"> 167</span>  [](<span class="keyword">const</span> <a class="code" href="structprocess_1_1Event.html">Event</a>* event) {</div><div class="line"><a name="l00168"></a><span class="lineno"> 168</span>  <span class="keywordflow">return</span> <span class="keyword">event</span>->is<T>();</div><div class="line"><a name="l00169"></a><span class="lineno"> 169</span>  });</div><div class="line"><a name="l00170"></a><span class="lineno"> 170</span>  }</
div><div class="line"><a name="l00171"></a><span class="lineno"> 171</span>  }</div><div class="line"><a name="l00172"></a><span class="lineno"> 172</span> </div><div class="line"><a name="l00173"></a><span class="lineno"> 173</span>  <span class="keyword">operator</span> <a class="code" href="structJSON_1_1Array.html">JSON::Array</a>()</div><div class="line"><a name="l00174"></a><span class="lineno"> 174</span>  {</div><div class="line"><a name="l00175"></a><span class="lineno"> 175</span>  <a class="code" href="structJSON_1_1Array.html">JSON::Array</a> array;</div><div class="line"><a name="l00176"></a><span class="lineno"> 176</span>  <span class="keyword">synchronized</span> (mutex) {</div><div class="line"><a name="l00177"></a><span class="lineno"> 177</span>  <span class="keywordflow">foreach</span> (<a class="code" href="structprocess_1_1Event.html">Event</a>* event, events) {</div><div class="line"><a name="l00178"></a>
<span class="lineno"> 178</span>  array.<a class="code" href="structJSON_1_1Array.html#aed41033b7cd6a2c2e7dcc6f0c48a4563">values</a>.push_back(<a class="code" href="structJSON_1_1Object.html">JSON::Object</a>(*event));</div><div class="line"><a name="l00179"></a><span class="lineno"> 179</span>  }</div><div class="line"><a name="l00180"></a><span class="lineno"> 180</span>  }</div><div class="line"><a name="l00181"></a><span class="lineno"> 181</span>  <span class="keywordflow">return</span> array;</div><div class="line"><a name="l00182"></a><span class="lineno"> 182</span>  }</div><div class="line"><a name="l00183"></a><span class="lineno"> 183</span> </div><div class="line"><a name="l00184"></a><span class="lineno"> 184</span>  std::mutex mutex;</div><div class="line"><a name="l00185"></a><span class="lineno"> 185</span>  std::deque<Event*> events;</div><div class="line"><a name="l00186"></a><span class="li
neno"> 186</span>  <span class="keywordtype">bool</span> comissioned = <span class="keyword">true</span>;</div><div class="line"><a name="l00187"></a><span class="lineno"> 187</span> <span class="preprocessor">#else // LOCK_FREE_EVENT_QUEUE</span></div><div class="line"><a name="l00188"></a><span class="lineno"> 188</span>  <span class="keywordtype">void</span> <a class="code" href="classprocess_1_1EventQueue_1_1Producer.html#a30a6a96aad51b429e48eba775a4a002d">enqueue</a>(<a class="code" href="structprocess_1_1Event.html">Event</a>* event)</div><div class="line"><a name="l00189"></a><span class="lineno"> 189</span>  {</div><div class="line"><a name="l00190"></a><span class="lineno"> 190</span>  Item item = {sequence.fetch_add(1), <span class="keyword">event</span>};</div><div class="line"><a name="l00191"></a><span class="lineno"> 191</span>  <span class="keywordflow">if</span> (comissioned.load()) {</div><div class="line"><a name="l00192
"></a><span class="lineno"> 192</span>  queue.enqueue(std::move(item));</div><div class="line"><a name="l00193"></a><span class="lineno"> 193</span>  } <span class="keywordflow">else</span> {</div><div class="line"><a name="l00194"></a><span class="lineno"> 194</span>  sequence.fetch_sub(1);</div><div class="line"><a name="l00195"></a><span class="lineno"> 195</span>  <span class="keyword">delete</span> event;</div><div class="line"><a name="l00196"></a><span class="lineno"> 196</span>  }</div><div class="line"><a name="l00197"></a><span class="lineno"> 197</span>  }</div><div class="line"><a name="l00198"></a><span class="lineno"> 198</span> </div><div class="line"><a name="l00199"></a><span class="lineno"> 199</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* dequeue()</div><div class="line"><a name="l00200"></a><span class="lineno"> 200</span>  {</div><div class="line"><a name="l0020
1"></a><span class="lineno"> 201</span>  <span class="comment">// NOTE: for performance reasons we don't check `comissioned` here</span></div><div class="line"><a name="l00202"></a><span class="lineno"> 202</span>  <span class="comment">// so it's possible that we'll loop forever if a consumer called</span></div><div class="line"><a name="l00203"></a><span class="lineno"> 203</span>  <span class="comment">// `decomission()` and then subsequently called `dequeue()`.</span></div><div class="line"><a name="l00204"></a><span class="lineno"> 204</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* <span class="keyword">event</span> = <span class="keyword">nullptr</span>;</div><div class="line"><a name="l00205"></a><span class="lineno"> 205</span>  <span class="keywordflow">do</span> {</div><div class="line"><a name="l00206"></a><span class="lineno"> 206</span>  <span class="comment">// Given the nature o
f the concurrent queue implementation it's</span></div><div class="line"><a name="l00207"></a><span class="lineno"> 207</span>  <span class="comment">// possible that we'll need to try to dequeue multiple times</span></div><div class="line"><a name="l00208"></a><span class="lineno"> 208</span>  <span class="comment">// until it returns an event even though we know there is an</span></div><div class="line"><a name="l00209"></a><span class="lineno"> 209</span>  <span class="comment">// event because the semantics are that we shouldn't call</span></div><div class="line"><a name="l00210"></a><span class="lineno"> 210</span>  <span class="comment">// `dequeue()` before calling `empty()`.</span></div><div class="line"><a name="l00211"></a><span class="lineno"> 211</span>  <span class="keyword">event</span> = try_dequeue();</div><div class="line"><a name="l00212"></a><span class="lineno"> 212</span>  } <span class=
"keywordflow">while</span> (event == <span class="keyword">nullptr</span>);</div><div class="line"><a name="l00213"></a><span class="lineno"> 213</span>  <span class="keywordflow">return</span> event;</div><div class="line"><a name="l00214"></a><span class="lineno"> 214</span>  }</div><div class="line"><a name="l00215"></a><span class="lineno"> 215</span> </div><div class="line"><a name="l00216"></a><span class="lineno"> 216</span>  <span class="keywordtype">bool</span> empty()</div><div class="line"><a name="l00217"></a><span class="lineno"> 217</span>  {</div><div class="line"><a name="l00218"></a><span class="lineno"> 218</span>  <span class="comment">// NOTE: for performance reasons we don't check `comissioned` here</span></div><div class="line"><a name="l00219"></a><span class="lineno"> 219</span>  <span class="comment">// so it's possible that we'll return true when in fact we've been</span></div><div class=
"line"><a name="l00220"></a><span class="lineno"> 220</span>  <span class="comment">// decomissioned and you shouldn't attempt to dequeue anything.</span></div><div class="line"><a name="l00221"></a><span class="lineno"> 221</span>  <span class="keywordflow">return</span> (sequence.load() - next) == 0;</div><div class="line"><a name="l00222"></a><span class="lineno"> 222</span>  }</div><div class="line"><a name="l00223"></a><span class="lineno"> 223</span> </div><div class="line"><a name="l00224"></a><span class="lineno"> 224</span>  <span class="keywordtype">void</span> decomission()</div><div class="line"><a name="l00225"></a><span class="lineno"> 225</span>  {</div><div class="line"><a name="l00226"></a><span class="lineno"> 226</span>  comissioned.store(<span class="keyword">true</span>);</div><div class="line"><a name="l00227"></a><span class="lineno"> 227</span>  <span class="keywordflow">while</span> (!empty()
) {</div><div class="line"><a name="l00228"></a><span class="lineno"> 228</span>  <span class="comment">// NOTE: we use `try_dequeue()` here because we might be racing</span></div><div class="line"><a name="l00229"></a><span class="lineno"> 229</span>  <span class="comment">// with `enqueue()` where they've already incremented `sequence`</span></div><div class="line"><a name="l00230"></a><span class="lineno"> 230</span>  <span class="comment">// so we think there are more items to dequeue but they aren't</span></div><div class="line"><a name="l00231"></a><span class="lineno"> 231</span>  <span class="comment">// actually going to enqueue anything because they've since seen</span></div><div class="line"><a name="l00232"></a><span class="lineno"> 232</span>  <span class="comment">// `comissioned` is true. We'll attempt to dequeue with</span></div><div class="line"><a name="l00233"></a><span class="lineno"> 233</sp
an>  <span class="comment">// `try_dequeue()` and eventually they'll decrement `sequence`</span></div><div class="line"><a name="l00234"></a><span class="lineno"> 234</span>  <span class="comment">// and so `empty()` will return true and we'll bail.</span></div><div class="line"><a name="l00235"></a><span class="lineno"> 235</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* <span class="keyword">event</span> = try_dequeue();</div><div class="line"><a name="l00236"></a><span class="lineno"> 236</span>  <span class="keywordflow">if</span> (event != <span class="keyword">nullptr</span>) {</div><div class="line"><a name="l00237"></a><span class="lineno"> 237</span>  <span class="keyword">delete</span> event;</div><div class="line"><a name="l00238"></a><span class="lineno"> 238</span>  }</div><div class="line"><a name="l00239"></a><span class="lineno"> 239</span>  }</div><div class="li
ne"><a name="l00240"></a><span class="lineno"> 240</span>  }</div><div class="line"><a name="l00241"></a><span class="lineno"> 241</span> </div><div class="line"><a name="l00242"></a><span class="lineno"> 242</span>  <span class="keyword">template</span> <<span class="keyword">typename</span> T></div><div class="line"><a name="l00243"></a><span class="lineno"> 243</span>  <span class="keywordtype">size_t</span> count()</div><div class="line"><a name="l00244"></a><span class="lineno"> 244</span>  {</div><div class="line"><a name="l00245"></a><span class="lineno"> 245</span>  <span class="comment">// Try and dequeue more elements first!</span></div><div class="line"><a name="l00246"></a><span class="lineno"> 246</span>  queue.try_dequeue_bulk(std::back_inserter(items), SIZE_MAX);</div><div class="line"><a name="l00247"></a><span class="lineno"> 247</span> </div><div class="line"><a name="l00248"></a><span class="lineno">
248</span>  <span class="keywordflow">return</span> std::count_if(</div><div class="line"><a name="l00249"></a><span class="lineno"> 249</span>  items.begin(),</div><div class="line"><a name="l00250"></a><span class="lineno"> 250</span>  items.end(),</div><div class="line"><a name="l00251"></a><span class="lineno"> 251</span>  [](<span class="keyword">const</span> Item& item) {</div><div class="line"><a name="l00252"></a><span class="lineno"> 252</span>  <span class="keywordflow">if</span> (item.event != <span class="keyword">nullptr</span>) {</div><div class="line"><a name="l00253"></a><span class="lineno"> 253</span>  <span class="keywordflow">return</span> item.event->is<T>();</div><div class="line"><a name="l00254"></a><span class="lineno"> 254</span>  }</div><div class="line"><a name="l00255"></a><span class="lineno"> 255</span>  <span class="keywordflow">r
eturn</span> <span class="keyword">false</span>;</div><div class="line"><a name="l00256"></a><span class="lineno"> 256</span>  });</div><div class="line"><a name="l00257"></a><span class="lineno"> 257</span>  }</div><div class="line"><a name="l00258"></a><span class="lineno"> 258</span> </div><div class="line"><a name="l00259"></a><span class="lineno"> 259</span>  <span class="keyword">operator</span> <a class="code" href="structJSON_1_1Array.html">JSON::Array</a>()</div><div class="line"><a name="l00260"></a><span class="lineno"> 260</span>  {</div><div class="line"><a name="l00261"></a><span class="lineno"> 261</span>  <span class="comment">// Try and dequeue more elements first!</span></div><div class="line"><a name="l00262"></a><span class="lineno"> 262</span>  queue.try_dequeue_bulk(std::back_inserter(items), SIZE_MAX);</div><div class="line"><a name="l00263"></a><span class="lineno"> 263</span> </div><div class="l
ine"><a name="l00264"></a><span class="lineno"> 264</span>  <a class="code" href="structJSON_1_1Array.html">JSON::Array</a> array;</div><div class="line"><a name="l00265"></a><span class="lineno"> 265</span>  <span class="keywordflow">foreach</span> (<span class="keyword">const</span> Item& item, items) {</div><div class="line"><a name="l00266"></a><span class="lineno"> 266</span>  <span class="keywordflow">if</span> (item.event != <span class="keyword">nullptr</span>) {</div><div class="line"><a name="l00267"></a><span class="lineno"> 267</span>  array.<a class="code" href="structJSON_1_1Array.html#aed41033b7cd6a2c2e7dcc6f0c48a4563">values</a>.push_back(<a class="code" href="structJSON_1_1Object.html">JSON::Object</a>(*item.event));</div><div class="line"><a name="l00268"></a><span class="lineno"> 268</span>  }</div><div class="line"><a name="l00269"></a><span class="lineno"> 269</span>  }</div><div class="line"><a n
ame="l00270"></a><span class="lineno"> 270</span> </div><div class="line"><a name="l00271"></a><span class="lineno"> 271</span>  <span class="keywordflow">return</span> array;</div><div class="line"><a name="l00272"></a><span class="lineno"> 272</span>  }</div><div class="line"><a name="l00273"></a><span class="lineno"> 273</span> </div><div class="line"><a name="l00274"></a><span class="lineno"> 274</span>  <span class="keyword">struct </span>Item</div><div class="line"><a name="l00275"></a><span class="lineno"> 275</span>  {</div><div class="line"><a name="l00276"></a><span class="lineno"> 276</span>  uint64_t sequence;</div><div class="line"><a name="l00277"></a><span class="lineno"> 277</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* event;</div><div class="line"><a name="l00278"></a><span class="lineno"> 278</span>  };</div><div class="line"><a name="l00279"></a><span class="lineno"> 279</
span> </div><div class="line"><a name="l00280"></a><span class="lineno"> 280</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* try_dequeue()</div><div class="line"><a name="l00281"></a><span class="lineno"> 281</span>  {</div><div class="line"><a name="l00282"></a><span class="lineno"> 282</span>  <span class="comment">// The general algoritm here is as follows: we bulk dequeue as</span></div><div class="line"><a name="l00283"></a><span class="lineno"> 283</span>  <span class="comment">// many items from the concurrent queue as possible. We then look</span></div><div class="line"><a name="l00284"></a><span class="lineno"> 284</span>  <span class="comment">// for the `next` item in the sequence hoping that it's at the</span></div><div class="line"><a name="l00285"></a><span class="lineno"> 285</span>  <span class="comment">// beginning of `items` but because the `queue` is not</span></div><div class="line"
><a name="l00286"></a><span class="lineno"> 286</span>  <span class="comment">// linearizable it might be "out of order". If we find it out of</span></div><div class="line"><a name="l00287"></a><span class="lineno"> 287</span>  <span class="comment">// order we effectively dequeue it but leave it in `items` so as</span></div><div class="line"><a name="l00288"></a><span class="lineno"> 288</span>  <span class="comment">// not to incur any costly rearrangements/compactions in</span></div><div class="line"><a name="l00289"></a><span class="lineno"> 289</span>  <span class="comment">// `items`. We'll later pop the out of order items once they get</span></div><div class="line"><a name="l00290"></a><span class="lineno"> 290</span>  <span class="comment">// to the front.</span></div><div class="line"><a name="l00291"></a><span class="lineno"> 291</span> </div><div class="line"><a name="l00292"></a><span class="lineno"> 292</
span>  <span class="comment">// Start by popping any items that we effectively dequeued but</span></div><div class="line"><a name="l00293"></a><span class="lineno"> 293</span>  <span class="comment">// didn't remove from `items` so as not to incur costly</span></div><div class="line"><a name="l00294"></a><span class="lineno"> 294</span>  <span class="comment">// rearragements/compactions.</span></div><div class="line"><a name="l00295"></a><span class="lineno"> 295</span>  <span class="keywordflow">while</span> (!items.empty() && next > items.front().sequence) {</div><div class="line"><a name="l00296"></a><span class="lineno"> 296</span>  items.pop_front();</div><div class="line"><a name="l00297"></a><span class="lineno"> 297</span>  }</div><div class="line"><a name="l00298"></a><span class="lineno"> 298</span> </div><div class="line"><a name="l00299"></a><span class="lineno"> 299</span>  <span class
="comment">// Optimistically let's hope that the next item is at the front of</span></div><div class="line"><a name="l00300"></a><span class="lineno"> 300</span>  <span class="comment">// `item`. If so, pop the item, increment `next`, and return the</span></div><div class="line"><a name="l00301"></a><span class="lineno"> 301</span>  <span class="comment">// event.</span></div><div class="line"><a name="l00302"></a><span class="lineno"> 302</span>  <span class="keywordflow">if</span> (!items.empty() && items.front().sequence == next) {</div><div class="line"><a name="l00303"></a><span class="lineno"> 303</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* <span class="keyword">event</span> = items.front().event;</div><div class="line"><a name="l00304"></a><span class="lineno"> 304</span>  items.pop_front();</div><div class="line"><a name="l00305"></a><span class="lineno"> 305</span>  next += 1;<
/div><div class="line"><a name="l00306"></a><span class="lineno"> 306</span>  <span class="keywordflow">return</span> event;</div><div class="line"><a name="l00307"></a><span class="lineno"> 307</span>  }</div><div class="line"><a name="l00308"></a><span class="lineno"> 308</span> </div><div class="line"><a name="l00309"></a><span class="lineno"> 309</span>  <span class="keywordtype">size_t</span> <a class="code" href="namespacerouting_1_1link.html#a26486cdba01ef1c80706b1e07e8a6d3f">index</a> = 0;</div><div class="line"><a name="l00310"></a><span class="lineno"> 310</span> </div><div class="line"><a name="l00311"></a><span class="lineno"> 311</span>  <span class="keywordflow">do</span> {</div><div class="line"><a name="l00312"></a><span class="lineno"> 312</span>  <span class="comment">// Now look for a potentially out of order item. If found,</span></div><div class="line"><a name="l00313"></a><span class="lineno"> 313</s
pan>  <span class="comment">// signifiy the item has been dequeued by nulling the event</span></div><div class="line"><a name="l00314"></a><span class="lineno"> 314</span>  <span class="comment">// (necessary for the implementation of `count()` and `operator</span></div><div class="line"><a name="l00315"></a><span class="lineno"> 315</span>  <span class="comment">// JSON::Array()`) and return the event.</span></div><div class="line"><a name="l00316"></a><span class="lineno"> 316</span>  <span class="keywordflow">for</span> (; index < items.size(); index++) {</div><div class="line"><a name="l00317"></a><span class="lineno"> 317</span>  <span class="keywordflow">if</span> (items[index].sequence == next) {</div><div class="line"><a name="l00318"></a><span class="lineno"> 318</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* <span class="keyword">event</span> = items[<a class="code" href="na
mespacerouting_1_1link.html#a26486cdba01ef1c80706b1e07e8a6d3f">index</a>].event;</div><div class="line"><a name="l00319"></a><span class="lineno"> 319</span>  items[<a class="code" href="namespacerouting_1_1link.html#a26486cdba01ef1c80706b1e07e8a6d3f">index</a>].event = <span class="keyword">nullptr</span>;</div><div class="line"><a name="l00320"></a><span class="lineno"> 320</span>  next += 1;</div><div class="line"><a name="l00321"></a><span class="lineno"> 321</span>  <span class="keywordflow">return</span> event;</div><div class="line"><a name="l00322"></a><span class="lineno"> 322</span>  }</div><div class="line"><a name="l00323"></a><span class="lineno"> 323</span>  }</div><div class="line"><a name="l00324"></a><span class="lineno"> 324</span> </div><div class="line"><a name="l00325"></a><span class="lineno"> 325</span>  <span class="comment">// If we can bulk dequeue more items then keep loo
king for the</span></div><div class="line"><a name="l00326"></a><span class="lineno"> 326</span>  <span class="comment">// out of order event!</span></div><div class="line"><a name="l00327"></a><span class="lineno"> 327</span>  <span class="comment">//</span></div><div class="line"><a name="l00328"></a><span class="lineno"> 328</span>  <span class="comment">// NOTE: we use the _small_ value of `4` to dequeue here since</span></div><div class="line"><a name="l00329"></a><span class="lineno"> 329</span>  <span class="comment">// in the presence of enough events being enqueued we could end</span></div><div class="line"><a name="l00330"></a><span class="lineno"> 330</span>  <span class="comment">// up spending a LONG time dequeuing here! Since the next event</span></div><div class="line"><a name="l00331"></a><span class="lineno"> 331</span>  <span class="comment">// in the sequence should really be close to the top of the
</span></div><div class="line"><a name="l00332"></a><span class="lineno"> 332</span>  <span class="comment">// queue we use a small value to dequeue.</span></div><div class="line"><a name="l00333"></a><span class="lineno"> 333</span>  <span class="comment">//</span></div><div class="line"><a name="l00334"></a><span class="lineno"> 334</span>  <span class="comment">// The intuition here is this: the faster we can return the next</span></div><div class="line"><a name="l00335"></a><span class="lineno"> 335</span>  <span class="comment">// event the faster that event can get processed and the faster</span></div><div class="line"><a name="l00336"></a><span class="lineno"> 336</span>  <span class="comment">// it might generate other events that can get processed in</span></div><div class="line"><a name="l00337"></a><span class="lineno"> 337</span>  <span class="comment">// parallel by other threads and the more work we get
done.</span></div><div class="line"><a name="l00338"></a><span class="lineno"> 338</span>  } <span class="keywordflow">while</span> (queue.try_dequeue_bulk(std::back_inserter(items), 4) != 0);</div><div class="line"><a name="l00339"></a><span class="lineno"> 339</span> </div><div class="line"><a name="l00340"></a><span class="lineno"> 340</span>  <span class="keywordflow">return</span> <span class="keyword">nullptr</span>;</div><div class="line"><a name="l00341"></a><span class="lineno"> 341</span>  }</div><div class="line"><a name="l00342"></a><span class="lineno"> 342</span> </div><div class="line"><a name="l00343"></a><span class="lineno"> 343</span>  <span class="comment">// Underlying queue of items.</span></div><div class="line"><a name="l00344"></a><span class="lineno"> 344</span>  moodycamel::ConcurrentQueue<Item> queue;</div><div class="line"><a name="l00345"></a><span class="lineno"> 345</span> </div><div class
="line"><a name="l00346"></a><span class="lineno"> 346</span>  <span class="comment">// Counter to represent the item sequence. Note that we use a</span></div><div class="line"><a name="l00347"></a><span class="lineno"> 347</span>  <span class="comment">// unsigned 64-bit integer which means that even if we were adding</span></div><div class="line"><a name="l00348"></a><span class="lineno"> 348</span>  <span class="comment">// one item to the queue every nanosecond we'd be able to run for</span></div><div class="line"><a name="l00349"></a><span class="lineno"> 349</span>  <span class="comment">// 18,446,744,073,709,551,615 nanoseconds or ~585 years! ;-)</span></div><div class="line"><a name="l00350"></a><span class="lineno"> 350</span>  std::atomic<uint64_t> sequence = ATOMIC_VAR_INIT(0);</div><div class="line"><a name="l00351"></a><span class="lineno"> 351</span> </div><div class="line"><a name="l00352"></a><span class="lineno"> 3
52</span>  <span class="comment">// Counter to represent the next item we expect to dequeue. Note</span></div><div class="line"><a name="l00353"></a><span class="lineno"> 353</span>  <span class="comment">// that we don't need to make this be atomic because only a single</span></div><div class="line"><a name="l00354"></a><span class="lineno"> 354</span>  <span class="comment">// consumer is ever reading or writing this variable!</span></div><div class="line"><a name="l00355"></a><span class="lineno"> 355</span>  uint64_t next = 0;</div><div class="line"><a name="l00356"></a><span class="lineno"> 356</span> </div><div class="line"><a name="l00357"></a><span class="lineno"> 357</span>  <span class="comment">// Collection of bulk dequeued items that may be out of order. Note</span></div><div class="line"><a name="l00358"></a><span class="lineno"> 358</span>  <span class="comment">// that like `next` this will only ever be read/written
by a single</span></div><div class="line"><a name="l00359"></a><span class="lineno"> 359</span>  <span class="comment">// consumer.</span></div><div class="line"><a name="l00360"></a><span class="lineno"> 360</span>  <span class="comment">//</span></div><div class="line"><a name="l00361"></a><span class="lineno"> 361</span>  <span class="comment">// The use of a deque was explicit because it is implemented as an</span></div><div class="line"><a name="l00362"></a><span class="lineno"> 362</span>  <span class="comment">// array of arrays (or vector of vectors) which usually gives good</span></div><div class="line"><a name="l00363"></a><span class="lineno"> 363</span>  <span class="comment">// performance for appending to the back and popping from the front</span></div><div class="line"><a name="l00364"></a><span class="lineno"> 364</span>  <span class="comment">// which is exactly what we need to do. To avoid any performance</span></div><div c
lass="line"><a name="l00365"></a><span class="lineno"> 365</span>  <span class="comment">// issues that might be incurred we do not remove any items from the</span></div><div class="line"><a name="l00366"></a><span class="lineno"> 366</span>  <span class="comment">// middle of the deque (see comments in `try_dequeue()` above for</span></div><div class="line"><a name="l00367"></a><span class="lineno"> 367</span>  <span class="comment">// more details).</span></div><div class="line"><a name="l00368"></a><span class="lineno"> 368</span>  std::deque<Item> items;</div><div class="line"><a name="l00369"></a><span class="lineno"> 369</span> </div><div class="line"><a name="l00370"></a><span class="lineno"> 370</span>  <span class="comment">// Whether or not the event queue has been decomissioned. This must</span></div><div class="line"><a name="l00371"></a><span class="lineno"> 371</span>  <span class="comment">// be atomic as it can be
read by a producer even though it's only</span></div><div class="line"><a name="l00372"></a><span class="lineno"> 372</span>  <span class="comment">// written by a consumer.</span></div><div class="line"><a name="l00373"></a><span class="lineno"> 373</span>  std::atomic<bool> comissioned = ATOMIC_VAR_INIT(<span class="keyword">true</span>);</div><div class="line"><a name="l00374"></a><span class="lineno"> 374</span> <span class="preprocessor">#endif // LOCK_FREE_EVENT_QUEUE</span></div><div class="line"><a name="l00375"></a><span class="lineno"> 375</span> };</div><div class="line"><a name="l00376"></a><span class="lineno"> 376</span> </div><div class="line"><a name="l00377"></a><span class="lineno"> 377</span> } <span class="comment">// namespace process {</span></div><div class="line"><a name="l00378"></a><span class="lineno"> 378</span> </div><div class="line"><a name="l00379"></a><span class="lineno"> 379</span> <span
class="preprocessor">#endif // __PROCESS_EVENT_QUEUE_HPP__</span></div><div class="ttc" id="synchronized_8hpp_html"><div class="ttname"><a href="synchronized_8hpp.html">synchronized.hpp</a></div></div>
+<a href="event__queue_8hpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span> <span class="comment">// Licensed under the Apache License, Version 2.0 (the "License");</span></div><div class="line"><a name="l00002"></a><span class="lineno"> 2</span> <span class="comment">// you may not use this file except in compliance with the License.</span></div><div class="line"><a name="l00003"></a><span class="lineno"> 3</span> <span class="comment">// You may obtain a copy of the License at</span></div><div class="line"><a name="l00004"></a><span class="lineno"> 4</span> <span class="comment">//</span></div><div class="line"><a name="l00005"></a><span class="lineno"> 5</span> <span class="comment">// http://www.apache.org/licenses/LICENSE-2.0</span></div><div class="line"><a name="l00006"></a><span class="lineno"> 6</span> <span class="comment">
//</span></div><div class="line"><a name="l00007"></a><span class="lineno"> 7</span> <span class="comment">// Unless required by applicable law or agreed to in writing, software</span></div><div class="line"><a name="l00008"></a><span class="lineno"> 8</span> <span class="comment">// distributed under the License is distributed on an "AS IS" BASIS,</span></div><div class="line"><a name="l00009"></a><span class="lineno"> 9</span> <span class="comment">// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span></div><div class="line"><a name="l00010"></a><span class="lineno"> 10</span> <span class="comment">// See the License for the specific language governing permissions and</span></div><div class="line"><a name="l00011"></a><span class="lineno"> 11</span> <span class="comment">// limitations under the License</span></div><div class="line"><a name="l00012"></a><span class="lineno"> 12</span> </div><div cla
ss="line"><a name="l00013"></a><span class="lineno"> 13</span> <span class="preprocessor">#ifndef __PROCESS_EVENT_QUEUE_HPP__</span></div><div class="line"><a name="l00014"></a><span class="lineno"> 14</span> <span class="preprocessor">#define __PROCESS_EVENT_QUEUE_HPP__</span></div><div class="line"><a name="l00015"></a><span class="lineno"> 15</span> </div><div class="line"><a name="l00016"></a><span class="lineno"> 16</span> <span class="preprocessor">#include <deque></span></div><div class="line"><a name="l00017"></a><span class="lineno"> 17</span> <span class="preprocessor">#include <mutex></span></div><div class="line"><a name="l00018"></a><span class="lineno"> 18</span> <span class="preprocessor">#include <string></span></div><div class="line"><a name="l00019"></a><span class="lineno"> 19</span> </div><div class="line"><a name="l00020"></a><span class="lineno"> 20</span> <span class="preprocessor">#incl
ude <<a class="code" href="event_8hpp.html">process/event.hpp</a>></span></div><div class="line"><a name="l00021"></a><span class="lineno"> 21</span> <span class="preprocessor">#include <<a class="code" href="3rdparty_2libprocess_2include_2process_2http_8hpp.html">process/http.hpp</a>></span></div><div class="line"><a name="l00022"></a><span class="lineno"> 22</span> </div><div class="line"><a name="l00023"></a><span class="lineno"> 23</span> <span class="preprocessor">#include <<a class="code" href="json_8hpp.html">stout/json.hpp</a>></span></div><div class="line"><a name="l00024"></a><span class="lineno"> 24</span> <span class="preprocessor">#include <<a class="code" href="stringify_8hpp.html">stout/stringify.hpp</a>></span></div><div class="line"><a name="l00025"></a><span class="lineno"> 25</span> <span class="preprocessor">#include <<a class="code" href="synchronized_8hpp.html">stout/synchronized.hpp</a>></span></
div><div class="line"><a name="l00026"></a><span class="lineno"> 26</span> </div><div class="line"><a name="l00027"></a><span class="lineno"> 27</span> <span class="preprocessor">#ifdef LOCK_FREE_EVENT_QUEUE</span></div><div class="line"><a name="l00028"></a><span class="lineno"> 28</span> <span class="preprocessor">#include "<a class="code" href="mpsc__linked__queue_8hpp.html">mpsc_linked_queue.hpp</a>"</span></div><div class="line"><a name="l00029"></a><span class="lineno"> 29</span> <span class="preprocessor">#endif // LOCK_FREE_EVENT_QUEUE</span></div><div class="line"><a name="l00030"></a><span class="lineno"> 30</span> </div><div class="line"><a name="l00031"></a><span class="lineno"> 31</span> <span class="keyword">namespace </span><a class="code" href="namespaceprocess.html">process</a> {</div><div class="line"><a name="l00032"></a><span class="lineno"> 32</span> </div><div class="line"><a name="l00033"></a><span cla
ss="lineno"> 33</span> <span class="comment">// A _multiple_ producer (MP) _single_ consumer (SC) event queue for a</span></div><div class="line"><a name="l00034"></a><span class="lineno"> 34</span> <span class="comment">// process. Note that we don't _enforce_ the MP/SC semantics during</span></div><div class="line"><a name="l00035"></a><span class="lineno"> 35</span> <span class="comment">// runtime but we have explicitly separated out the `Producer`</span></div><div class="line"><a name="l00036"></a><span class="lineno"> 36</span> <span class="comment">// interface and the `Consumer` interface in order to help avoid</span></div><div class="line"><a name="l00037"></a><span class="lineno"> 37</span> <span class="comment">// incorrect usage.</span></div><div class="line"><a name="l00038"></a><span class="lineno"> 38</span> <span class="comment">//</span></div><div class="line"><a name="l00039"></a><span class="lineno"> 39</span> <
span class="comment">// Notable semantics:</span></div><div class="line"><a name="l00040"></a><span class="lineno"> 40</span> <span class="comment">//</span></div><div class="line"><a name="l00041"></a><span class="lineno"> 41</span> <span class="comment">// * Consumers _must_ call `empty()` before calling</span></div><div class="line"><a name="l00042"></a><span class="lineno"> 42</span> <span class="comment">// `dequeue()`. Failing to do so may result in undefined behavior.</span></div><div class="line"><a name="l00043"></a><span class="lineno"> 43</span> <span class="comment">//</span></div><div class="line"><a name="l00044"></a><span class="lineno"> 44</span> <span class="comment">// * After a consumer calls `decomission()` they _must_ not call any</span></div><div class="line"><a name="l00045"></a><span class="lineno"> 45</span> <span class="comment">// thing else (not even `empty()` and especially not</span></div><div class=
"line"><a name="l00046"></a><span class="lineno"> 46</span> <span class="comment">// `dequeue()`). Doing so is undefined behavior.</span></div><div class="line"><a name="l00047"></a><span class="lineno"> 47</span> <span class="comment">//</span></div><div class="line"><a name="l00048"></a><span class="lineno"> 48</span> <span class="comment">// Notes on the lock-free implementation:</span></div><div class="line"><a name="l00049"></a><span class="lineno"> 49</span> <span class="comment">//</span></div><div class="line"><a name="l00050"></a><span class="lineno"> 50</span> <span class="comment">// The SC requirement is necessary for the lock-free implementation</span></div><div class="line"><a name="l00051"></a><span class="lineno"> 51</span> <span class="comment">// because the underlying queue does not provide linearizability which</span></div><div class="line"><a name="l00052"></a><span class="lineno"> 52</span> <span class="comme
nt">// means events can be dequeued "out of order". Usually this is not a</span></div><div class="line"><a name="l00053"></a><span class="lineno"> 53</span> <span class="comment">// problem, after all, in most circumstances we won't know the order</span></div><div class="line"><a name="l00054"></a><span class="lineno"> 54</span> <span class="comment">// in which events might be enqueued in the first place. However, this</span></div><div class="line"><a name="l00055"></a><span class="lineno"> 55</span> <span class="comment">// can be a very bad problem if a single process attempts to enqueue</span></div><div class="line"><a name="l00056"></a><span class="lineno"> 56</span> <span class="comment">// two events in a different process AND THOSE EVENTS ARE</span></div><div class="line"><a name="l00057"></a><span class="lineno"> 57</span> <span class="comment">// REORDERED. To ensure this will never be the case we give every</span></div><div
class="line"><a name="l00058"></a><span class="lineno"> 58</span> <span class="comment">// event a sequence number. That way an event from the same process</span></div><div class="line"><a name="l00059"></a><span class="lineno"> 59</span> <span class="comment">// will always have a happens-before relationship with respect to the</span></div><div class="line"><a name="l00060"></a><span class="lineno"> 60</span> <span class="comment">// events that they enqueue because they'll have distinct sequence</span></div><div class="line"><a name="l00061"></a><span class="lineno"> 61</span> <span class="comment">// numbers.</span></div><div class="line"><a name="l00062"></a><span class="lineno"> 62</span> <span class="comment">//</span></div><div class="line"><a name="l00063"></a><span class="lineno"> 63</span> <span class="comment">// This makes the consumer implementation more difficult because the</span></div><div class="line"><a name="l00064"><
/a><span class="lineno"> 64</span> <span class="comment">// consumer might need to "reorder" events as it reads them out. To do</span></div><div class="line"><a name="l00065"></a><span class="lineno"> 65</span> <span class="comment">// this efficiently we require only a single consumer, which fits well</span></div><div class="line"><a name="l00066"></a><span class="lineno"> 66</span> <span class="comment">// into the actor model because there will only ever be a single</span></div><div class="line"><a name="l00067"></a><span class="lineno"> 67</span> <span class="comment">// thread consuming an actors events at a time.</span></div><div class="line"><a name="l00068"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue.html"> 68</a></span> <span class="keyword">class </span><a class="code" href="classprocess_1_1EventQueue.html">EventQueue</a></div><div class="line"><a name="l00069"></a><span class="lineno"> 69</span>&
#160;{</div><div class="line"><a name="l00070"></a><span class="lineno"> 70</span> <span class="keyword">public</span>:</div><div class="line"><a name="l00071"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue.html#ad2d51d8a2a80f473de0bcf2e08e48d90"> 71</a></span>  <a class="code" href="classprocess_1_1EventQueue.html#ad2d51d8a2a80f473de0bcf2e08e48d90">EventQueue</a>() : <a class="code" href="classprocess_1_1EventQueue.html#aa95046266e731af49ccfb9d689cb1eca">producer</a>(this), <a class="code" href="classprocess_1_1EventQueue.html#a73f44b10f6d09ead6bdf3ab11cba4d06">consumer</a>(this) {}</div><div class="line"><a name="l00072"></a><span class="lineno"> 72</span> </div><div class="line"><a name="l00073"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Producer.html"> 73</a></span>  <span class="keyword">class </span><a class="code" href="classprocess_1_1EventQueue_1_1Producer.html">Producer</a></div><div
class="line"><a name="l00074"></a><span class="lineno"> 74</span>  {</div><div class="line"><a name="l00075"></a><span class="lineno"> 75</span>  <span class="keyword">public</span>:</div><div class="line"><a name="l00076"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Producer.html#a30a6a96aad51b429e48eba775a4a002d"> 76</a></span>  <span class="keywordtype">void</span> <a class="code" href="classprocess_1_1EventQueue_1_1Producer.html#a30a6a96aad51b429e48eba775a4a002d">enqueue</a>(<a class="code" href="structprocess_1_1Event.html">Event</a>* event) { queue->enqueue(event); }</div><div class="line"><a name="l00077"></a><span class="lineno"> 77</span> </div><div class="line"><a name="l00078"></a><span class="lineno"> 78</span>  <span class="keyword">private</span>:</div><div class="line"><a name="l00079"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Producer.html#a3b1787a64e5e97ce
075c05a58303d58c"> 79</a></span>  <span class="keyword">friend</span> <span class="keyword">class </span><a class="code" href="classprocess_1_1EventQueue.html">EventQueue</a>;</div><div class="line"><a name="l00080"></a><span class="lineno"> 80</span> </div><div class="line"><a name="l00081"></a><span class="lineno"> 81</span>  <a class="code" href="classprocess_1_1EventQueue_1_1Producer.html">Producer</a>(<a class="code" href="classprocess_1_1EventQueue.html">EventQueue</a>* queue) : queue(queue) {}</div><div class="line"><a name="l00082"></a><span class="lineno"> 82</span> </div><div class="line"><a name="l00083"></a><span class="lineno"> 83</span>  <a class="code" href="classprocess_1_1EventQueue.html">EventQueue</a>* queue;</div><div class="line"><a name="l00084"></a><span class="lineno"> 84</span>  } <a class="code" href="classprocess_1_1EventQueue.html#aa95046266e731af49ccfb9d689cb1eca">producer</a>;</div><div class="line"><a
name="l00085"></a><span class="lineno"> 85</span> </div><div class="line"><a name="l00086"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Consumer.html"> 86</a></span>  <span class="keyword">class </span><a class="code" href="classprocess_1_1EventQueue_1_1Consumer.html">Consumer</a></div><div class="line"><a name="l00087"></a><span class="lineno"> 87</span>  {</div><div class="line"><a name="l00088"></a><span class="lineno"> 88</span>  <span class="keyword">public</span>:</div><div class="line"><a name="l00089"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Consumer.html#a0947a38c4933c27cc6b422ce9171a400"> 89</a></span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* <a class="code" href="classprocess_1_1EventQueue_1_1Consumer.html#a0947a38c4933c27cc6b422ce9171a400">dequeue</a>() { <span class="keywordflow">return</span> queue->dequeue(); }</div><div class="line"><
a name="l00090"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Consumer.html#aa42de8d3e7ba7c56362a36efa773790d"> 90</a></span>  <span class="keywordtype">bool</span> <a class="code" href="classprocess_1_1EventQueue_1_1Consumer.html#aa42de8d3e7ba7c56362a36efa773790d">empty</a>() { <span class="keywordflow">return</span> queue->empty(); }</div><div class="line"><a name="l00091"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Consumer.html#a7976eeb2b9ff88c5f03551c63764a162"> 91</a></span>  <span class="keywordtype">void</span> <a class="code" href="classprocess_1_1EventQueue_1_1Consumer.html#a7976eeb2b9ff88c5f03551c63764a162">decomission</a>() { queue->decomission(); }</div><div class="line"><a name="l00092"></a><span class="lineno"> 92</span>  <span class="keyword">template</span> <<span class="keyword">typename</span> T></div><div class="line"><a name="l00093"></a><span class="lineno"
><a class="line" href="classprocess_1_1EventQueue_1_1Consumer.html#a8d998919af90a6146e6745a1217be3ce"> 93</a></span>  <span class="keywordtype">size_t</span> <a class="code" href="classprocess_1_1EventQueue_1_1Consumer.html#a8d998919af90a6146e6745a1217be3ce">count</a>() { <span class="keywordflow">return</span> queue->count<T>(); }</div><div class="line"><a name="l00094"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Consumer.html#a307aaa062d7b5feee064e0361a3cb166"> 94</a></span>  <span class="keyword">operator</span> <a class="code" href="structJSON_1_1Array.html">JSON::Array</a>() { <span class="keywordflow">return</span> queue->operator <a class="code" href="structJSON_1_1Array.html">JSON::Array</a>(); }</div><div class="line"><a name="l00095"></a><span class="lineno"> 95</span> </div><div class="line"><a name="l00096"></a><span class="lineno"> 96</span>  <span class="keyword">private</span>:</div><div c
lass="line"><a name="l00097"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue_1_1Consumer.html#a3b1787a64e5e97ce075c05a58303d58c"> 97</a></span>  <span class="keyword">friend</span> <span class="keyword">class </span><a class="code" href="classprocess_1_1EventQueue.html">EventQueue</a>;</div><div class="line"><a name="l00098"></a><span class="lineno"> 98</span> </div><div class="line"><a name="l00099"></a><span class="lineno"> 99</span>  <a class="code" href="classprocess_1_1EventQueue.html#a11390aaa07bced511a5b7fe4c94e97fd">Consumer</a>(<a class="code" href="classprocess_1_1EventQueue.html">EventQueue</a>* queue) : queue(queue) {}</div><div class="line"><a name="l00100"></a><span class="lineno"> 100</span> </div><div class="line"><a name="l00101"></a><span class="lineno"> 101</span>  <a class="code" href="classprocess_1_1EventQueue.html">EventQueue</a>* queue;</div><div class="line"><a name="l00102"></a><span class=
"lineno"> 102</span>  } <a class="code" href="classprocess_1_1EventQueue.html#a73f44b10f6d09ead6bdf3ab11cba4d06">consumer</a>;</div><div class="line"><a name="l00103"></a><span class="lineno"> 103</span> </div><div class="line"><a name="l00104"></a><span class="lineno"> 104</span> <span class="keyword">private</span>:</div><div class="line"><a name="l00105"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue.html#aaf00b363e56ec3a72a6f775a3814d6a0"> 105</a></span>  <span class="keyword">friend</span> <span class="keyword">class </span><a class="code" href="classprocess_1_1EventQueue_1_1Producer.html">Producer</a>;</div><div class="line"><a name="l00106"></a><span class="lineno"><a class="line" href="classprocess_1_1EventQueue.html#a11390aaa07bced511a5b7fe4c94e97fd"> 106</a></span>  <span class="keyword">friend</span> <span class="keyword">class </span><a class="code" href="classprocess_1_1EventQueue_1_1Consumer.html">Consumer</a>
;</div><div class="line"><a name="l00107"></a><span class="lineno"> 107</span> </div><div class="line"><a name="l00108"></a><span class="lineno"> 108</span> <span class="preprocessor">#ifndef LOCK_FREE_EVENT_QUEUE</span></div><div class="line"><a name="l00109"></a><span class="lineno"> 109</span>  <span class="keywordtype">void</span> <a class="code" href="classprocess_1_1EventQueue_1_1Producer.html#a30a6a96aad51b429e48eba775a4a002d">enqueue</a>(<a class="code" href="structprocess_1_1Event.html">Event</a>* event)</div><div class="line"><a name="l00110"></a><span class="lineno"> 110</span>  {</div><div class="line"><a name="l00111"></a><span class="lineno"> 111</span>  <span class="keywordtype">bool</span> enqueued = <span class="keyword">false</span>;</div><div class="line"><a name="l00112"></a><span class="lineno"> 112</span>  <span class="keyword">synchronized</span> (mutex) {</div><div class="line"><a name="l00113"></a><span class="line
no"> 113</span>  <span class="keywordflow">if</span> (comissioned) {</div><div class="line"><a name="l00114"></a><span class="lineno"> 114</span>  events.push_back(event);</div><div class="line"><a name="l00115"></a><span class="lineno"> 115</span>  enqueued = <span class="keyword">true</span>;</div><div class="line"><a name="l00116"></a><span class="lineno"> 116</span>  }</div><div class="line"><a name="l00117"></a><span class="lineno"> 117</span>  }</div><div class="line"><a name="l00118"></a><span class="lineno"> 118</span> </div><div class="line"><a name="l00119"></a><span class="lineno"> 119</span>  <span class="keywordflow">if</span> (!enqueued) {</div><div class="line"><a name="l00120"></a><span class="lineno"> 120</span>  <span class="keyword">delete</span> event;</div><div class="line"><a name="l00121"></a><span class="lineno"> 121</span>  }</div><div class="line"><a name="l00122"></
a><span class="lineno"> 122</span>  }</div><div class="line"><a name="l00123"></a><span class="lineno"> 123</span> </div><div class="line"><a name="l00124"></a><span class="lineno"> 124</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* dequeue()</div><div class="line"><a name="l00125"></a><span class="lineno"> 125</span>  {</div><div class="line"><a name="l00126"></a><span class="lineno"> 126</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* <span class="keyword">event</span> = <span class="keyword">nullptr</span>;</div><div class="line"><a name="l00127"></a><span class="lineno"> 127</span> </div><div class="line"><a name="l00128"></a><span class="lineno"> 128</span>  <span class="keyword">synchronized</span> (mutex) {</div><div class="line"><a name="l00129"></a><span class="lineno"> 129</span>  <span class="keywordflow">if</span> (events.size() > 0) {</div><div class="line"><a n
ame="l00130"></a><span class="lineno"> 130</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* <span class="keyword">event</span> = events.front();</div><div class="line"><a name="l00131"></a><span class="lineno"> 131</span>  events.pop_front();</div><div class="line"><a name="l00132"></a><span class="lineno"> 132</span>  <span class="keywordflow">return</span> event;</div><div class="line"><a name="l00133"></a><span class="lineno"> 133</span>  }</div><div class="line"><a name="l00134"></a><span class="lineno"> 134</span>  }</div><div class="line"><a name="l00135"></a><span class="lineno"> 135</span> </div><div class="line"><a name="l00136"></a><span class="lineno"> 136</span>  <span class="comment">// Semantics are the consumer _must_ call `empty()` before calling</span></div><div class="line"><a name="l00137"></a><span class="lineno"> 137</span>  <span class="comment">// `dequeue()
` which means an event must be present.</span></div><div class="line"><a name="l00138"></a><span class="lineno"> 138</span>  <span class="keywordflow">return</span> CHECK_NOTNULL(event);</div><div class="line"><a name="l00139"></a><span class="lineno"> 139</span>  }</div><div class="line"><a name="l00140"></a><span class="lineno"> 140</span> </div><div class="line"><a name="l00141"></a><span class="lineno"> 141</span>  <span class="keywordtype">bool</span> empty()</div><div class="line"><a name="l00142"></a><span class="lineno"> 142</span>  {</div><div class="line"><a name="l00143"></a><span class="lineno"> 143</span>  <span class="keyword">synchronized</span> (mutex) {</div><div class="line"><a name="l00144"></a><span class="lineno"> 144</span>  <span class="keywordflow">return</span> events.size() == 0;</div><div class="line"><a name="l00145"></a><span class="lineno"> 145</span>  }</div><div class="line"><a name="l00
146"></a><span class="lineno"> 146</span>  }</div><div class="line"><a name="l00147"></a><span class="lineno"> 147</span> </div><div class="line"><a name="l00148"></a><span class="lineno"> 148</span>  <span class="keywordtype">void</span> decomission()</div><div class="line"><a name="l00149"></a><span class="lineno"> 149</span>  {</div><div class="line"><a name="l00150"></a><span class="lineno"> 150</span>  <span class="keyword">synchronized</span> (mutex) {</div><div class="line"><a name="l00151"></a><span class="lineno"> 151</span>  comissioned = <span class="keyword">false</span>;</div><div class="line"><a name="l00152"></a><span class="lineno"> 152</span>  <span class="keywordflow">while</span> (!events.empty()) {</div><div class="line"><a name="l00153"></a><span class="lineno"> 153</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* <span class="keyword">event</span> = events.front();</div>
<div class="line"><a name="l00154"></a><span class="lineno"> 154</span>  events.pop_front();</div><div class="line"><a name="l00155"></a><span class="lineno"> 155</span>  <span class="keyword">delete</span> event;</div><div class="line"><a name="l00156"></a><span class="lineno"> 156</span>  }</div><div class="line"><a name="l00157"></a><span class="lineno"> 157</span>  }</div><div class="line"><a name="l00158"></a><span class="lineno"> 158</span>  }</div><div class="line"><a name="l00159"></a><span class="lineno"> 159</span> </div><div class="line"><a name="l00160"></a><span class="lineno"> 160</span>  <span class="keyword">template</span> <<span class="keyword">typename</span> T></div><div class="line"><a name="l00161"></a><span class="lineno"> 161</span>  <span class="keywordtype">size_t</span> count()</div><div class="line"><a name="l00162"></a><span class="lineno"> 162</span>  {</div><div class
="line"><a name="l00163"></a><span class="lineno"> 163</span>  <span class="keyword">synchronized</span> (mutex) {</div><div class="line"><a name="l00164"></a><span class="lineno"> 164</span>  <span class="keywordflow">return</span> std::count_if(</div><div class="line"><a name="l00165"></a><span class="lineno"> 165</span>  events.begin(),</div><div class="line"><a name="l00166"></a><span class="lineno"> 166</span>  events.end(),</div><div class="line"><a name="l00167"></a><span class="lineno"> 167</span>  [](<span class="keyword">const</span> <a class="code" href="structprocess_1_1Event.html">Event</a>* event) {</div><div class="line"><a name="l00168"></a><span class="lineno"> 168</span>  <span class="keywordflow">return</span> <span class="keyword">event</span>->is<T>();</div><div class="line"><a name="l00169"></a><span class="lineno"> 169</span>  });</div><div class="line"><a
name="l00170"></a><span class="lineno"> 170</span>  }</div><div class="line"><a name="l00171"></a><span class="lineno"> 171</span>  }</div><div class="line"><a name="l00172"></a><span class="lineno"> 172</span> </div><div class="line"><a name="l00173"></a><span class="lineno"> 173</span>  <span class="keyword">operator</span> <a class="code" href="structJSON_1_1Array.html">JSON::Array</a>()</div><div class="line"><a name="l00174"></a><span class="lineno"> 174</span>  {</div><div class="line"><a name="l00175"></a><span class="lineno"> 175</span>  <a class="code" href="structJSON_1_1Array.html">JSON::Array</a> array;</div><div class="line"><a name="l00176"></a><span class="lineno"> 176</span>  <span class="keyword">synchronized</span> (mutex) {</div><div class="line"><a name="l00177"></a><span class="lineno"> 177</span>  <span class="keywordflow">foreach</span> (<a class="code" href="structprocess_1_1Event.html">Event</
a>* event, events) {</div><div class="line"><a name="l00178"></a><span class="lineno"> 178</span>  array.<a class="code" href="structJSON_1_1Array.html#aed41033b7cd6a2c2e7dcc6f0c48a4563">values</a>.push_back(<a class="code" href="structJSON_1_1Object.html">JSON::Object</a>(*event));</div><div class="line"><a name="l00179"></a><span class="lineno"> 179</span>  }</div><div class="line"><a name="l00180"></a><span class="lineno"> 180</span>  }</div><div class="line"><a name="l00181"></a><span class="lineno"> 181</span>  <span class="keywordflow">return</span> array;</div><div class="line"><a name="l00182"></a><span class="lineno"> 182</span>  }</div><div class="line"><a name="l00183"></a><span class="lineno"> 183</span> </div><div class="line"><a name="l00184"></a><span class="lineno"> 184</span>  std::mutex mutex;</div><div class="line"><a name="l00185"></a><span class="lineno"> 185</span>  std::deque<Event*> ev
ents;</div><div class="line"><a name="l00186"></a><span class="lineno"> 186</span>  <span class="keywordtype">bool</span> comissioned = <span class="keyword">true</span>;</div><div class="line"><a name="l00187"></a><span class="lineno"> 187</span> <span class="preprocessor">#else // LOCK_FREE_EVENT_QUEUE</span></div><div class="line"><a name="l00188"></a><span class="lineno"> 188</span>  <span class="keywordtype">void</span> <a class="code" href="classprocess_1_1EventQueue_1_1Producer.html#a30a6a96aad51b429e48eba775a4a002d">enqueue</a>(<a class="code" href="structprocess_1_1Event.html">Event</a>* event)</div><div class="line"><a name="l00189"></a><span class="lineno"> 189</span>  {</div><div class="line"><a name="l00190"></a><span class="lineno"> 190</span>  <span class="keywordflow">if</span> (comissioned.load()) {</div><div class="line"><a name="l00191"></a><span class="lineno"> 191</span>  queue.enqueue(event);</div><div class="line"
><a name="l00192"></a><span class="lineno"> 192</span>  } <span class="keywordflow">else</span> {</div><div class="line"><a name="l00193"></a><span class="lineno"> 193</span>  <span class="keyword">delete</span> event;</div><div class="line"><a name="l00194"></a><span class="lineno"> 194</span>  }</div><div class="line"><a name="l00195"></a><span class="lineno"> 195</span>  }</div><div class="line"><a name="l00196"></a><span class="lineno"> 196</span> </div><div class="line"><a name="l00197"></a><span class="lineno"> 197</span>  <a class="code" href="structprocess_1_1Event.html">Event</a>* dequeue()</div><div class="line"><a name="l00198"></a><span class="lineno"> 198</span>  {</div><div class="line"><a name="l00199"></a><span class="lineno"> 199</span>  <span class="keywordflow">return</span> queue.dequeue();</div><div class="line"><a name="l00200"></a><span class="lineno"> 200</span>  }</div><div class="line">
<a name="l00201"></a><span class="lineno"> 201</span> </div><div class="line"><a name="l00202"></a><span class="lineno"> 202</span>  <span class="keywordtype">bool</span> empty()</div><div class="line"><a name="l00203"></a><span class="lineno"> 203</span>  {</div><div class="line"><a name="l00204"></a><span class="lineno"> 204</span>  <span class="keywordflow">return</span> queue.empty();</div><div class="line"><a name="l00205"></a><span class="lineno"> 205</span>  }</div><div class="line"><a name="l00206"></a><span class="lineno"> 206</span> </div><div class="line"><a name="l00207"></a><span class="lineno"> 207</span>  <span class="keywordtype">void</span> decomission()</div><div class="line"><a name="l00208"></a><span class="lineno"> 208</span>  {</div><div class="line"><a name="l00209"></a><span class="lineno"> 209</span>  comissioned.store(<span class="keyword">true</span>);</div><div class="line
<TRUNCATED>