lib: Mostly complete matcher

Input matching and completions works. Still some
rough edges.

Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>

1 files changed, 178 insertions, 3 deletions

diff --git a/lib/command_match.c b/lib/command_match.c
index bcc28bdc5b..f7e2789253 100644
--- a/lib/command_match.c
+++ b/lib/command_match.c
@@ -1,12 +1,187 @@
 #include <zebra.h>
 #include "memory.h"
+#include "vector.h"
 #include "command_match.h"
 
-enum match_type
+static enum match_type
+match_token (struct graph_node *node, char *token, enum filter_type filter)
+{
+  switch (node->type) {
+    case WORD_GN:
+      return cmd_word_match (node, filter, token);
+    case IPV4_GN:
+      return cmd_ipv4_match (token);
+    case IPV4_PREFIX_GN:
+      return cmd_ipv4_prefix_match (token);
+    case IPV6_GN:
+      return cmd_ipv6_match (token);
+    case IPV6_PREFIX_GN:
+      return cmd_ipv6_prefix_match (token);
+    case RANGE_GN:
+      return cmd_range_match (node, token);
+    case NUMBER_GN:
+      return node->value == atoi(token);
+    case VARIABLE_GN:
+    default:
+      return no_match;
+  }
+}
+
+/* Breaking up string into each command piece. I assume given
+   character is separated by a space character. Return value is a
+   vector which includes char ** data element. */
+static vector
+cmd_make_strvec (const char *string)
+{
+  const char *cp, *start;
+  char *token;
+  int strlen;
+  vector strvec;
+
+  if (string == NULL)
+    return NULL;
+
+  cp = string;
+
+  /* Skip white spaces. */
+  while (isspace ((int) *cp) && *cp != '\0')
+    cp++;
+
+  /* Return if there is only white spaces */
+  if (*cp == '\0')
+    return NULL;
+
+  if (*cp == '!' || *cp == '#')
+    return NULL;
+
+  /* Prepare return vector. */
+  strvec = vector_init (VECTOR_MIN_SIZE);
+
+  /* Copy each command piece and set into vector. */
+  while (1)
+    {
+      start = cp;
+      while (!(isspace ((int) *cp) || *cp == '\r' || *cp == '\n') &&
+            *cp != '\0')
+         cp++;
+      strlen = cp - start;
+      token = XMALLOC (MTYPE_STRVEC, strlen + 1);
+      memcpy (token, start, strlen);
+      *(token + strlen) = '\0';
+      vector_set (strvec, token);
+
+      while ((isspace ((int) *cp) || *cp == '\n' || *cp == '\r') &&
+            *cp != '\0')
+         cp++;
+
+      if (*cp == '\0')
+        return strvec;
+    }
+}
+
+/**
+ * Adds all children that are reachable by one parser hop
+ * to the given list. NUL_GN, SELECTOR_GN, and OPTION_GN
+ * nodes are treated as though their children are attached
+ * to their parent.
+ *
+ * @param[out] l the list to add the children to
+ * @param[in] node the node to get the children of
+ * @return the number of children added to the list
+ */
+static int
+add_nexthops(struct list *l, struct graph_node *node)
+{
+  int added = 0;
+  struct graph_node *child;
+  for (unsigned int i = 0; i < vector_active(node->children); i++)
+  {
+    child = vector_slot(node->children, i);
+    if (child->type == OPTION_GN || child->type == SELECTOR_GN || child->type == NUL_GN)
+      added += add_nexthops(l, child);
+    else {
+      listnode_add(l, child);
+      added++;
+    }
+  }
+  return added;
+}
+
+/**
+ * Compiles matches or next-hops for a given line of user input.
+ *
+ * Given a string of input and a start node for a matching DFA, runs the input
+ * against the DFA until the input is exhausted, there are no possible
+ * transitions, or both.
+ * If there are no further state transitions available, one of two scenarios is possible:
+ *  - The end of input has been reached. This indicates a valid command.
+ *  - The end of input has not yet been reached. The input does not match any command.
+ * If there are further transitions available, one of two scenarios is possible:
+ *  - The current input is a valid prefix to a longer command
+ *  - The current input matches a command
+ *  - The current input matches a command, and is also a valid prefix to a longer command
+ *
+ * Any other states indicate a programming error.
+ *
+ * @param[in] start the start node of the DFA to match against
+ * @param[in] filter the filtering method
+ * @param[in] input the input string
+ * @return an array with two lists. The first list is
+ */
+struct list**
 match_command (struct graph_node *start, enum filter_type filter, const char *input)
 {
-  // match input on DFA
-  return exact_match;
+  // break command
+  vector command = cmd_make_strvec (input);
+
+  // pointer to next input token to match
+  char *token;
+
+  struct list *current  = list_new(), // current nodes to match input token against
+              *matched  = list_new(), // current nodes that match the input token
+              *next     = list_new(); // possible next hops to current input token
+
+  // pointers used for iterating lists
+  struct graph_node *cnode;
+  struct listnode *node;
+
+  // add all children of start node to list
+  add_nexthops(next, start);
+
+  unsigned int idx;
+  for (idx = 0; idx < vector_active(command) && next->count > 0; idx++)
+  {
+    list_free (current);
+    current = next;
+    next = list_new();
+
+    token = vector_slot(command, idx);
+
+    list_delete_all_node(matched);
+
+    for (ALL_LIST_ELEMENTS_RO(current,node,cnode))
+    {
+      if (match_token(cnode, token, filter) == exact_match) {
+        listnode_add(matched, cnode);
+        add_nexthops(next, cnode);
+      }
+    }
+  }
+
+  /* Variable summary
+   * -----------------------------------------------------------------
+   * token    = last input token processed
+   * idx      = index in `command` of last token processed
+   * current  = set of all transitions from the previous input token
+   * matched  = set of all nodes reachable with current input
+   * next     = set of all nodes reachable from all nodes in `matched`
+   */
+
+  struct list **result = malloc( 2 * sizeof(struct list *) );
+  result[0] = matched;
+  result[1] = next;
+
+  return result;
 }