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NaviServer urlspace Data Structure(n) 4.99.2 ""

NAME

NaviServer urlspace Data Structure - NaviServer urlspace Data Structure

TABLE OF CONTENTS

    TABLE OF CONTENTS
    DESCRIPTION
    The urlspace Trie

DESCRIPTION

The urlspace Trie

There are four basic data structures used in maintaining the urlspace trie. They are:

  1. Junction A junction is nothing more than a list of channels.



  2. Channel A channel points to a branch which ultimately leads to nodes that match a particular "filter", such as "*.html". The filter is the last section of a URL mask, and is the only part of the mask that may contain wildcards.



  3. Branch A branch represents one part of a URL, such as a server, method, directory, or wildcard filename. It has a list of branches representing sub-URLs as well as a pointer to a list of Nodes.



  4. Node A node stores URL-specific data, as well as a pointer to the cleanup function.
Another data structure, called an Index, which is manipulated by the ns_Index API calls, is used by the urlspace code. An Index is an ordered list of pointers. The order is determined by callback functions. See index.c for the scoop on that. Here is what the urlspace data structure would look like after calling

ns_UrlSpecificSet("server1", "GET", "/foo/bar/*.html", myID, myData, 0, MyDeleteProc);

 


------------------------------------------------------------------------------

urlspace: JUNCTION
  byname: INDEX [*][ ][ ][ ][ ]
                 |
  +--------------+
  |
  V
CHANNEL
  filter:  CHAR*   "*.html"
  trie:    TRIE
             indexnode: INDEX* (NULL)
	     branches:  INDEX  [*][ ][ ][ ][ ]
	                        |
  +-----------------------------+
  |
  V
BRANCH
  word: CHAR* "server1"
  node: TRIE
          indexnode: INDEX* (NULL)
	  branches:  INDEX  [*][ ][ ][ ][ ]
	                     |
  +--------------------------+
  |
  V
BRANCH
  word: CHAR* "GET"
  node: TRIE
          indexnode: INDEX* (NULL)
	  branches:  INDEX  [*][ ][ ][ ][ ]
	                     |
  +--------------------------+
  |
  V
BRANCH
  word: CHAR* "foo"
  node: TRIE
          indexnode: INDEX* (NULL)
	  branches:  INDEX  [*][ ][ ][ ][ ]
	                     |
  +--------------------------+
  |
  V
BRANCH
  word: CHAR* "*.html"
  node: TRIE
          indexnode: INDEX* -----------------> [*][ ][ ][ ][ ]
	  branches:  INDEX  [ ][ ][ ][ ][ ]     |
	                                        |
  +---------------------------------------------+
  |
  V
NODE
  id:                  INT               myID
  dataInherit:         VOID*             myData
  dataNoInherit:       VOID*             0
  deleteFuncInherit:   VOID(*)(VOID*)    MyDeleteProc
  deleteFuncNoInherit: VOID(*)(VOID*)    0