1 /* 2 * Graph data structure. 3 * 4 * -- 5 * Copyright (C) 2016 Cumulus Networks, Inc. 6 * 7 * This file is part of GNU Zebra. 8 * 9 * GNU Zebra is free software; you can redistribute it and/or modify it 10 * under the terms of the GNU General Public License as published by the 11 * Free Software Foundation; either version 2, or (at your option) any 12 * later version. 13 * 14 * GNU Zebra is distributed in the hope that it will be useful, but 15 * WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 * General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License along 20 * with this program; see the file COPYING; if not, write to the Free Software 21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 22 */ 23 24 #ifndef _ZEBRA_COMMAND_GRAPH_H 25 #define _ZEBRA_COMMAND_GRAPH_H 26 27 #include <stdbool.h> 28 #include "vector.h" 29 #include "buffer.h" 30 31 #ifdef __cplusplus 32 extern "C" { 33 #endif 34 35 struct graph { 36 vector nodes; 37 }; 38 39 struct graph_node { 40 vector from; // nodes which have edges to this node 41 vector to; // nodes which this node has edges to 42 43 void *data; // node data 44 void (*del)(void *data); // deletion callback 45 }; 46 47 struct graph *graph_new(void); 48 49 /** 50 * Creates a new node. 51 * 52 * @struct graph the graph this node exists in 53 * @param[in] data this node's data 54 * @param[in] del data deletion callback 55 * @return the new node 56 */ 57 struct graph_node *graph_new_node(struct graph *graph, void *data, 58 void (*del)(void *)); 59 60 /** 61 * Deletes a node. 62 * 63 * Before deletion, this function removes all edges to and from this node from 64 * any neighbor nodes. 65 * 66 * If *data and *del are non-null, the following call is made: 67 * (*node->del) (node->data); 68 * 69 * @param[in] graph the graph this node belongs to 70 * @param[out] node pointer to node to delete 71 */ 72 void graph_delete_node(struct graph *graph, struct graph_node *node); 73 74 /** 75 * Makes a directed edge between two nodes. 76 * 77 * @param[in] from 78 * @param[in] to 79 * @return to 80 */ 81 struct graph_node *graph_add_edge(struct graph_node *from, 82 struct graph_node *to); 83 84 /** 85 * Removes a directed edge between two nodes. 86 * 87 * @param[in] from 88 * @param[in] to 89 */ 90 void graph_remove_edge(struct graph_node *from, struct graph_node *to); 91 92 /** 93 * Deletes a graph. 94 * Calls graph_delete_node on each node before freeing the graph struct itself. 95 * 96 * @param graph the graph to delete 97 */ 98 void graph_delete_graph(struct graph *graph); 99 100 /* 101 * Finds a node in the graph. 102 * 103 * @param[in] graph the graph to search in 104 * @param[in] data the data to key off 105 * @return the first graph node whose data pointer matches `data` 106 */ 107 struct graph_node *graph_find_node(struct graph *graph, void *data); 108 109 110 /* 111 * Determines whether two nodes have a directed edge between them. 112 * 113 * @param from 114 * @param to 115 * @return whether there is a directed edge from `from` to `to`. 116 */ 117 bool graph_has_edge(struct graph_node *from, struct graph_node *to); 118 119 /* 120 * Depth-first search. 121 * 122 * Performs a depth-first traversal of the given graph, visiting each node 123 * exactly once and calling the user-provided callback for each visit. 124 * 125 * @param graph the graph to operate on 126 * @param start the node to take as the root 127 * @param dfs_cb callback called for each node visited in the traversal 128 * @param arg argument to provide to dfs_cb 129 */ 130 void graph_dfs(struct graph *graph, struct graph_node *start, 131 void (*dfs_cb)(struct graph_node *, void *), void *arg); 132 133 #ifndef BUILDING_CLIPPY 134 /* 135 * Clippy relies on a small subset of sources in lib/, but it cannot link 136 * libfrr since clippy itself is required to build libfrr. Instead it directly 137 * includes the sources it needs. One of these is the command graph 138 * implementation, which wraps this graph implementation. Since we need to use 139 * the buffer.[ch] sources here, which indirectly rely on most of libfrr, we 140 * have to ignore them when compiling clippy to avoid build dependency issues. 141 * 142 * TODO: Fix clippy build. 143 */ 144 145 /* 146 * Default node printer for use with graph_dump_dot. 147 * 148 * @param gn the node to print 149 * @param buf the buffer to print into 150 */ 151 void graph_dump_dot_default_print_cb(struct graph_node *gn, struct buffer *buf); 152 153 /* 154 * Prints a graph in the DOT language. 155 * 156 * The generated output is produced from a depth-first traversal of the graph. 157 * 158 * @param graph the graph to print 159 * @param start the node to take as the root 160 * @param pcb callback called for each node in the traversal that should 161 * print the node in the DOT language. Passing NULL for this argument 162 * will use the default printer. See graph_dump_dot_default_print_cb for 163 * an example. 164 * @return representation of graph in DOT language, allocated with MTYPE_TMP. 165 * Caller is responsible for freeing this string. 166 */ 167 char *graph_dump_dot(struct graph *graph, struct graph_node *start, 168 void (*pcb)(struct graph_node *, struct buffer *buf)); 169 170 #endif /* BUILDING_CLIPPY */ 171 172 #ifdef __cplusplus 173 } 174 #endif 175 176 #endif /* _ZEBRA_COMMAND_GRAPH_H */ 177