lib/command_graph.h

   1 #ifndef COMMAND_GRAPH_H
   2 #define COMMAND_GRAPH_H
   3
   4 #include "command.h"
   5
   6 enum graph_node_type
   7 {
   8   WORD_GN,
   9   IPV4_GN,
  10   IPV4_PREFIX_GN,
  11   IPV6_GN,
  12   IPV6_PREFIX_GN,
  13   VARIABLE_GN,
  14   RANGE_GN,
  15   NUMBER_GN,
  16   SELECTOR_GN,
  17   OPTION_GN,
  18   NUL_GN,
  19   START_GN,
  20   END_GN
  21 };
  22
  23 struct graph_node
  24 {
  25   enum graph_node_type type;// data type this node matches or holds
  26   int is_start;             // whether this node is a start node
  27   vector children;          // this node's children
  28   struct graph_node * end;  // pointer to end for SELECTOR_GN & OPTION_GN
  29
  30   char* text;               // for WORD_GN and VARIABLE_GN
  31   long value;               // for NUMBER_GN
  32   long min, max;            // for RANGE_GN
  33
  34   /* cmd_element struct pointer, only valid for END_GN */
  35   struct cmd_element *element;
  36   /* used for passing arguments to command functions */
  37   char *arg;
  38 };
  39
  40 /*
  41  * Adds a node as a child of another node.
  42  * If the new parent has a child that is equal to the prospective child, as
  43  * determined by cmp_node, then a pointer to the existing node is returned and
  44  * the prospective child is not added. Otherwise the return value is NULL.
  45  *
  46  * @param[in] parent node
  47  * @param[in] child node
  48  * @return pointer to child if it is added, pointer to existing child otherwise
  49  */
  50 extern struct graph_node *
  51 add_node(struct graph_node *, struct graph_node *);
  52
  53 /*
  54  * Compares two nodes for parsing equivalence.
  55  * Equivalence in this case means that a single user input token
  56  * should be able to unambiguously match one of the two nodes.
  57  * For example, two nodes which have all fields equal except their
  58  * function pointers would be considered equal.
  59  *
  60  * @param[in] first node to compare
  61  * @param[in] second node to compare
  62  * @return 1 if equal, zero otherwise.
  63  */
  64 extern int
  65 cmp_node(struct graph_node *, struct graph_node *);
  66
  67 /*
  68  * Create a new node.
  69  * Initializes all fields to default values and sets the node type.
  70  *
  71  * @param[in] node type
  72  * @return pointer to the newly allocated node
  73  */
  74 extern struct graph_node *
  75 new_node(enum graph_node_type);
  76
  77 /**
  78  * Walks a command DFA, printing structure to stdout.
  79  * For debugging.
  80  *
  81  * @param[in] start node of graph to walk
  82  * @param[in] graph depth for recursion, caller passes 0
  83  */
  84 extern void
  85 walk_graph(struct graph_node *, int);
  86
  87 /**
  88  * Returns a string representation of the given node.
  89  * @param[in] the node to describe
  90  * @param[out] the buffer to write the description into
  91  * @return pointer to description string
  92  */
  93 extern char *
  94 describe_node(struct graph_node *, char *, unsigned int);
  95
  96 /**
  97  * Frees the data associated with a graph_node.
  98  * @param[out] pointer to graph_node to free
  99  */
 100 void
 101 free_node(struct graph_node *);
 102 #endif