<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/> <meta http-equiv="X-UA-Compatible" content="IE=9"/> <meta name="generator" content="Doxygen 1.8.11"/> <title>proxygen: proxygen/folly/folly/experimental/observer/detail/GraphCycleDetector.h Source File</title> <link href="tabs.css" rel="stylesheet" type="text/css"/> <script type="text/javascript" src="jquery.js"></script> <script type="text/javascript" src="dynsections.js"></script> <link href="navtree.css" rel="stylesheet" type="text/css"/> <script type="text/javascript" src="resize.js"></script> <script type="text/javascript" src="navtreedata.js"></script> <script type="text/javascript" src="navtree.js"></script> <script type="text/javascript"> $(document).ready(initResizable); $(window).load(resizeHeight); </script> <link href="doxygen.css" 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href="globals.html"><span>File Members</span></a></li> </ul> </div> </div><!-- top --> <div id="side-nav" class="ui-resizable side-nav-resizable"> <div id="nav-tree"> <div id="nav-tree-contents"> <div id="nav-sync" class="sync"></div> </div> </div> <div id="splitbar" style="-moz-user-select:none;" class="ui-resizable-handle"> </div> </div> <script type="text/javascript"> $(document).ready(function(){initNavTree('GraphCycleDetector_8h_source.html','');}); </script> <div id="doc-content"> <div class="header"> <div class="headertitle"> <div class="title">GraphCycleDetector.h</div> </div> </div><!--header--> <div class="contents"> <a href="GraphCycleDetector_8h.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">/*</span></div><div class="line"><a name="l00002"></a><span class="lineno"> 2</span> <span class="comment"> * Copyright 2016-present Facebook, Inc.</span></div><div class="line"><a name="l00003"></a><span class="lineno"> 3</span> <span class="comment"> *</span></div><div class="line"><a name="l00004"></a><span class="lineno"> 4</span> <span class="comment"> * Licensed under the Apache License, Version 2.0 (the "License");</span></div><div class="line"><a name="l00005"></a><span class="lineno"> 5</span> <span class="comment"> * you may not use this file except in compliance with the License.</span></div><div class="line"><a name="l00006"></a><span class="lineno"> 6</span> <span class="comment"> * You may obtain a copy of the License at</span></div><div class="line"><a name="l00007"></a><span class="lineno"> 7</span> <span class="comment"> *</span></div><div class="line"><a name="l00008"></a><span class="lineno"> 8</span> <span class="comment"> * http://www.apache.org/licenses/LICENSE-2.0</span></div><div class="line"><a name="l00009"></a><span class="lineno"> 9</span> <span class="comment"> *</span></div><div class="line"><a name="l00010"></a><span class="lineno"> 10</span> <span class="comment"> * Unless required by applicable law or agreed to in writing, software</span></div><div class="line"><a name="l00011"></a><span class="lineno"> 11</span> <span class="comment"> * distributed under the License is distributed on an "AS IS" BASIS,</span></div><div class="line"><a name="l00012"></a><span class="lineno"> 12</span> <span class="comment"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span></div><div class="line"><a name="l00013"></a><span class="lineno"> 13</span> <span class="comment"> * See the License for the specific language governing permissions and</span></div><div class="line"><a name="l00014"></a><span class="lineno"> 14</span> <span class="comment"> * limitations under the License.</span></div><div class="line"><a name="l00015"></a><span class="lineno"> 15</span> <span class="comment"> */</span></div><div class="line"><a name="l00016"></a><span class="lineno"> 16</span> <span class="preprocessor">#pragma once</span></div><div class="line"><a name="l00017"></a><span class="lineno"> 17</span> </div><div class="line"><a name="l00018"></a><span class="lineno"> 18</span> <span class="preprocessor">#include <unordered_map></span></div><div class="line"><a name="l00019"></a><span class="lineno"> 19</span> <span class="preprocessor">#include <unordered_set></span></div><div class="line"><a name="l00020"></a><span class="lineno"> 20</span> </div><div class="line"><a name="l00021"></a><span class="lineno"> 21</span> <span class="preprocessor">#include <glog/logging.h></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="keyword">namespace </span><a class="code" href="namespacefolly.html">folly</a> {</div><div class="line"><a name="l00024"></a><span class="lineno"> 24</span> <span class="keyword">namespace </span>observer_detail {</div><div class="line"><a name="l00025"></a><span class="lineno"> 25</span> </div><div class="line"><a name="l00026"></a><span class="lineno"> 26</span> <span class="keyword">template</span> <<span class="keyword">typename</span> NodeId></div><div class="line"><a name="l00027"></a><span class="lineno"><a class="line" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html"> 27</a></span> <span class="keyword">class </span><a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html">GraphCycleDetector</a> {</div><div class="line"><a name="l00028"></a><span class="lineno"><a class="line" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#ac554e6e938b2cd0c2991fd51f3e519d6"> 28</a></span>  <span class="keyword">using</span> <a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#ac554e6e938b2cd0c2991fd51f3e519d6">NodeSet</a> = std::unordered_set<NodeId>;</div><div class="line"><a name="l00029"></a><span class="lineno"> 29</span> </div><div class="line"><a name="l00030"></a><span class="lineno"> 30</span>  <span class="keyword">public</span>:</div><div class="line"><a name="l00035"></a><span class="lineno"><a class="line" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#affdc3d3089bb7d3041be6de694e8e816"> 35</a></span>  <span class="keywordtype">bool</span> <a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#affdc3d3089bb7d3041be6de694e8e816">addEdge</a>(NodeId <a class="code" href="namespacefolly_1_1pushmi_1_1operators.html#a66a275bf0c134161fd2050e9ec72a29d">from</a>, NodeId <a class="code" href="namespacefolly.html#a005f91db4ecc55675cf5ad7ba25ec24d">to</a>) {</div><div class="line"><a name="l00036"></a><span class="lineno"> 36</span>  <span class="comment">// In general case DFS may be expensive here, but in most cases to-node will</span></div><div class="line"><a name="l00037"></a><span class="lineno"> 37</span>  <span class="comment">// have no edges, so it should be O(1).</span></div><div class="line"><a name="l00038"></a><span class="lineno"> 38</span>  <a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#ac554e6e938b2cd0c2991fd51f3e519d6">NodeSet</a> visitedNodes;</div><div class="line"><a name="l00039"></a><span class="lineno"> 39</span>  <a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#a8810ee05d97141c3133942f715b002c7">dfs</a>(visitedNodes, to);</div><div class="line"><a name="l00040"></a><span class="lineno"> 40</span>  <span class="keywordflow">if</span> (visitedNodes.count(from)) {</div><div class="line"><a name="l00041"></a><span class="lineno"> 41</span>  <span class="keywordflow">return</span> <span class="keyword">false</span>;</div><div class="line"><a name="l00042"></a><span class="lineno"> 42</span>  }</div><div class="line"><a name="l00043"></a><span class="lineno"> 43</span> </div><div class="line"><a name="l00044"></a><span class="lineno"> 44</span>  <span class="keyword">auto</span>& nodes = <a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#a5d92327659c25deee7a83cb2ff2d5394">edges_</a>[<a class="code" href="namespacefolly_1_1pushmi_1_1operators.html#a66a275bf0c134161fd2050e9ec72a29d">from</a>];</div><div class="line"><a name="l00045"></a><span class="lineno"> 45</span>  DCHECK_EQ(nodes.count(to), 0u);</div><div class="line"><a name="l00046"></a><span class="lineno"> 46</span>  nodes.insert(to);</div><div class="line"><a name="l00047"></a><span class="lineno"> 47</span> </div><div class="line"><a name="l00048"></a><span class="lineno"> 48</span>  <span class="keywordflow">return</span> <span class="keyword">true</span>;</div><div class="line"><a name="l00049"></a><span class="lineno"> 49</span>  }</div><div class="line"><a name="l00050"></a><span class="lineno"> 50</span> </div><div class="line"><a name="l00051"></a><span class="lineno"><a class="line" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#af22b4c49188c01cd96b18fa62650b4fb"> 51</a></span>  <span class="keywordtype">void</span> <a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#af22b4c49188c01cd96b18fa62650b4fb">removeEdge</a>(NodeId <a class="code" href="namespacefolly_1_1pushmi_1_1operators.html#a66a275bf0c134161fd2050e9ec72a29d">from</a>, NodeId <a class="code" href="namespacefolly.html#a005f91db4ecc55675cf5ad7ba25ec24d">to</a>) {</div><div class="line"><a name="l00052"></a><span class="lineno"> 52</span>  <span class="keyword">auto</span>& nodes = <a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#a5d92327659c25deee7a83cb2ff2d5394">edges_</a>[<a class="code" href="namespacefolly_1_1pushmi_1_1operators.html#a66a275bf0c134161fd2050e9ec72a29d">from</a>];</div><div class="line"><a name="l00053"></a><span class="lineno"> 53</span>  DCHECK(nodes.count(to));</div><div class="line"><a name="l00054"></a><span class="lineno"> 54</span>  nodes.erase(to);</div><div class="line"><a name="l00055"></a><span class="lineno"> 55</span>  <span class="keywordflow">if</span> (nodes.empty()) {</div><div class="line"><a name="l00056"></a><span class="lineno"> 56</span>  <a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#a5d92327659c25deee7a83cb2ff2d5394">edges_</a>.erase(from);</div><div class="line"><a name="l00057"></a><span class="lineno"> 57</span>  }</div><div class="line"><a name="l00058"></a><span class="lineno"> 58</span>  }</div><div class="line"><a name="l00059"></a><span class="lineno"> 59</span> </div><div class="line"><a name="l00060"></a><span class="lineno"> 60</span>  <span class="keyword">private</span>:</div><div class="line"><a name="l00061"></a><span class="lineno"><a class="line" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#a8810ee05d97141c3133942f715b002c7"> 61</a></span>  <span class="keywordtype">void</span> <a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#a8810ee05d97141c3133942f715b002c7">dfs</a>(<a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#ac554e6e938b2cd0c2991fd51f3e519d6">NodeSet</a>& visitedNodes, NodeId node) {</div><div class="line"><a name="l00062"></a><span class="lineno"> 62</span>  <span class="comment">// We don't terminate early if cycle is detected, because this is considered</span></div><div class="line"><a name="l00063"></a><span class="lineno"> 63</span>  <span class="comment">// an error condition, so not worth optimizing for.</span></div><div class="line"><a name="l00064"></a><span class="lineno"> 64</span>  <span class="keywordflow">if</span> (visitedNodes.count(node)) {</div><div class="line"><a name="l00065"></a><span class="lineno"> 65</span>  <span class="keywordflow">return</span>;</div><div class="line"><a name="l00066"></a><span class="lineno"> 66</span>  }</div><div class="line"><a name="l00067"></a><span class="lineno"> 67</span> </div><div class="line"><a name="l00068"></a><span class="lineno"> 68</span>  visitedNodes.insert(node);</div><div class="line"><a name="l00069"></a><span class="lineno"> 69</span> </div><div class="line"><a name="l00070"></a><span class="lineno"> 70</span>  <span class="keywordflow">if</span> (!<a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#a5d92327659c25deee7a83cb2ff2d5394">edges_</a>.count(node)) {</div><div class="line"><a name="l00071"></a><span class="lineno"> 71</span>  <span class="keywordflow">return</span>;</div><div class="line"><a name="l00072"></a><span class="lineno"> 72</span>  }</div><div class="line"><a name="l00073"></a><span class="lineno"> 73</span> </div><div class="line"><a name="l00074"></a><span class="lineno"> 74</span>  <span class="keywordflow">for</span> (<span class="keyword">const</span> <span class="keyword">auto</span>& <a class="code" href="namespacefolly.html#a005f91db4ecc55675cf5ad7ba25ec24d">to</a> : <a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#a5d92327659c25deee7a83cb2ff2d5394">edges_</a>[node]) {</div><div class="line"><a name="l00075"></a><span class="lineno"> 75</span>  <a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#a8810ee05d97141c3133942f715b002c7">dfs</a>(visitedNodes, <a class="code" href="namespacefolly.html#a005f91db4ecc55675cf5ad7ba25ec24d">to</a>);</div><div class="line"><a name="l00076"></a><span class="lineno"> 76</span>  }</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> </div><div class="line"><a name="l00079"></a><span class="lineno"><a class="line" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#a5d92327659c25deee7a83cb2ff2d5394"> 79</a></span>  std::unordered_map<NodeId, NodeSet> <a class="code" href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#a5d92327659c25deee7a83cb2ff2d5394">edges_</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> } <span class="comment">// namespace observer_detail</span></div><div class="line"><a name="l00082"></a><span class="lineno"> 82</span> } <span class="comment">// namespace folly</span></div><div class="ttc" id="classfolly_1_1observer__detail_1_1GraphCycleDetector_html_a8810ee05d97141c3133942f715b002c7"><div class="ttname"><a href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#a8810ee05d97141c3133942f715b002c7">folly::observer_detail::GraphCycleDetector::dfs</a></div><div class="ttdeci">void dfs(NodeSet &visitedNodes, NodeId node)</div><div class="ttdef"><b>Definition:</b> <a href="GraphCycleDetector_8h_source.html#l00061">GraphCycleDetector.h:61</a></div></div> <div class="ttc" id="namespacefolly_html"><div class="ttname"><a href="namespacefolly.html">folly</a></div><div class="ttdoc">—— Concurrent Priority Queue Implementation —— </div><div class="ttdef"><b>Definition:</b> <a href="AtomicBitSet_8h_source.html#l00029">AtomicBitSet.h:29</a></div></div> <div class="ttc" id="classfolly_1_1observer__detail_1_1GraphCycleDetector_html_a5d92327659c25deee7a83cb2ff2d5394"><div class="ttname"><a href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#a5d92327659c25deee7a83cb2ff2d5394">folly::observer_detail::GraphCycleDetector::edges_</a></div><div class="ttdeci">std::unordered_map< NodeId, NodeSet > edges_</div><div class="ttdef"><b>Definition:</b> <a href="GraphCycleDetector_8h_source.html#l00079">GraphCycleDetector.h:79</a></div></div> <div class="ttc" id="classfolly_1_1observer__detail_1_1GraphCycleDetector_html_af22b4c49188c01cd96b18fa62650b4fb"><div class="ttname"><a href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#af22b4c49188c01cd96b18fa62650b4fb">folly::observer_detail::GraphCycleDetector::removeEdge</a></div><div class="ttdeci">void removeEdge(NodeId from, NodeId to)</div><div class="ttdef"><b>Definition:</b> <a href="GraphCycleDetector_8h_source.html#l00051">GraphCycleDetector.h:51</a></div></div> <div class="ttc" id="namespacefolly_html_a005f91db4ecc55675cf5ad7ba25ec24d"><div class="ttname"><a href="namespacefolly.html#a005f91db4ecc55675cf5ad7ba25ec24d">folly::to</a></div><div class="ttdeci">std::enable_if< detail::is_chrono_conversion< Tgt, Src >::value, Tgt >::type to(const Src &value)</div><div class="ttdef"><b>Definition:</b> <a href="chrono_2Conv_8h_source.html#l00677">Conv.h:677</a></div></div> <div class="ttc" id="classfolly_1_1observer__detail_1_1GraphCycleDetector_html_ac554e6e938b2cd0c2991fd51f3e519d6"><div class="ttname"><a href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#ac554e6e938b2cd0c2991fd51f3e519d6">folly::observer_detail::GraphCycleDetector::NodeSet</a></div><div class="ttdeci">std::unordered_set< NodeId > NodeSet</div><div class="ttdef"><b>Definition:</b> <a href="GraphCycleDetector_8h_source.html#l00028">GraphCycleDetector.h:28</a></div></div> <div class="ttc" id="namespacefolly_1_1pushmi_1_1operators_html_a66a275bf0c134161fd2050e9ec72a29d"><div class="ttname"><a href="namespacefolly_1_1pushmi_1_1operators.html#a66a275bf0c134161fd2050e9ec72a29d">folly::pushmi::operators::from</a></div><div class="ttdeci">PUSHMI_INLINE_VAR constexpr struct folly::pushmi::operators::from_fn from</div></div> <div class="ttc" id="classfolly_1_1observer__detail_1_1GraphCycleDetector_html_affdc3d3089bb7d3041be6de694e8e816"><div class="ttname"><a href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html#affdc3d3089bb7d3041be6de694e8e816">folly::observer_detail::GraphCycleDetector::addEdge</a></div><div class="ttdeci">bool addEdge(NodeId from, NodeId to)</div><div class="ttdef"><b>Definition:</b> <a href="GraphCycleDetector_8h_source.html#l00035">GraphCycleDetector.h:35</a></div></div> <div class="ttc" id="classfolly_1_1observer__detail_1_1GraphCycleDetector_html"><div class="ttname"><a href="classfolly_1_1observer__detail_1_1GraphCycleDetector.html">folly::observer_detail::GraphCycleDetector</a></div><div class="ttdef"><b>Definition:</b> <a href="GraphCycleDetector_8h_source.html#l00027">GraphCycleDetector.h:27</a></div></div> </div><!-- fragment --></div><!-- contents --> </div><!-- doc-content --> <!-- start footer part --> <div id="nav-path" class="navpath"><!-- id is needed for treeview function! --> <ul> <li class="navelem"><a class="el" href="dir_d333e33cf903653326082c1f32e03be5.html">proxygen</a></li><li 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