+++ /dev/null
-/* $Id: tdx-structure.h 5327 2002-03-16 00:33:55Z rra $
-**
-** Data structures for the tradindexed overview method.
-**
-** This header defines the data structures used by the tradindexed overview
-** method. Currently, these data structures are read and written directly to
-** disk (and the disk files are therefore endian-dependent and possibly
-** architecture-dependent due to structure padding). This will eventually be
-** fixed.
-**
-** The structure of a tradindexed overview spool is as follows: At the root
-** of the spool is a group.index file composed of a struct group_header
-** followed by some number of struct group_entry's, one for each group plus
-** possibly some number of free entries linked to a free list that's headed
-** in the struct index_header. Each entry corresponds to a particular
-** newsgroup carried by the server and stores the high and low article
-** numbers for that group, its status flag, and the base of the index file
-** for each group.
-**
-** The storage of the group.index file implements a hash table with chaining;
-** in other words, there is a table indexed by hash value stored in the
-** header that points to the starts of the chains, new entries are appended
-** to the end of the file and added to the hash table, and if they collide
-** with an existing entry are instead linked to the appropriate hash chain.
-**
-** The overview information for each group is stored in a pair of files named
-** <group>.IDX and <group>.DAT. These files are found in a subdirectory
-** formed by taking the first letter of component of the newsgroup name as
-** a directory name; in other words, news.announce.newgroups overview data is
-** stored in <pathoverview>/n/a/n/news.announce.newgroups.{IDX,DAT}. The
-** .DAT file contains the individual overview entries, one per line, stored
-** in wire format (in other words, suitable for dumping directly across the
-** network to a client in response to an XOVER command). The overview data
-** stored in that file may be out of order.
-**
-** The .IDX file consists of a series of struct index_entry's, one for each
-** overview entry stored in the .DAT file. Each index entry stores the
-** offset of the data for one article in the .DAT file and its length, along
-** with some additional metainformation about the article used to drive
-** article expiration. The .IDX file is addressed like an array; the first
-** entry corresponds to the article with the number stored in the base field
-** of the group_entry for that newsgroup in the group.index file and each
-** entry stores the data for the next consecutive article. Index entries may
-** be tagged as deleted if that article has been deleted or expired.
-*/
-
-#ifndef INN_TDX_STRUCTURE_H
-#define INN_TDX_STRUCTURE_H 1
-
-#include "config.h"
-#include <sys/types.h>
-
-#include "libinn.h"
-#include "storage.h"
-
-/* A location in group.index (this many records past the end of the header of
- the file). There's no reason for this to be a struct, but that can't be
- changed until the format of the group.index file is changed to be
- architecture-independent since putting it into a struct may have changed
- the alignment or padding on some architectures. */
-struct loc {
- int recno;
-};
-
-/* The hard-coded constant size of the hash table for group.index. This need
- not be a power of two and has no special constraints. Changing this at
- present will break backward compatibility with group.index files written by
- previous versions of the code. */
-#define TDX_HASH_SIZE (16 * 1024)
-
-/* A magic number for the group.index file so that we can later change the
- format in a backward-compatible fashion. */
-#define TDX_MAGIC (~(0xf1f0f33d))
-
-/* The header at the top of group.index. magic contains GROUPHEADERMAGIC
- always; hash contains pointers to the heads of the entry chains, and
- freelist points to a linked list of free entries (entries that were used
- for groups that have since been deleted). */
-struct group_header {
- int magic;
- struct loc hash[TDX_HASH_SIZE];
- struct loc freelist;
-};
-
-/* An entry for a particular group. Note that a good bit of active file
- information is duplicated here, and depending on the portion of INN asking
- questions, sometimes the main active file is canonical and sometimes the
- overview data is canonical. This needs to be rethought at some point.
-
- Groups are matched based on the MD5 hash of their name. This may prove
- inadequate in the future. Ideally, INN really needs to assign unique
- numbers to each group, which could then be used here as well as in
- tradspool rather than having to do hacks like using a hash of the group
- name or constructing one's own number to name mapping like tradspool does.
- Unfortunately, this ideally requires a non-backward-compatible change to
- the active file format.
-
- Several of these elements aren't used. This structure, like the others,
- cannot be changed until the whole format of the group.index file is changed
- since it's currently read as binary structs directly from disk. */
-struct group_entry {
- HASH hash; /* MD5 hash of the group name. */
- HASH alias; /* Intended to point to the group this group
- is an alias for. Not currently used. */
- ARTNUM high; /* High article number in the group. */
- ARTNUM low; /* Low article number in the group. */
- ARTNUM base; /* Article number of the first entry in the
- .IDX index file for the group. */
- int count; /* Number of articles in group. */
- int flag; /* Posting/moderation status. */
- time_t deleted; /* When this group was deleted, or 0 if the
- group is still valid. */
- ino_t indexinode; /* The inode of the index file for the group,
- used to detect when the file has been
- recreated and swapped out. */
- struct loc next; /* Next block in this chain. */
-};
-
-/* An entry in the per-group .IDX index file. */
-struct index_entry {
- off_t offset;
- int length;
- time_t arrived;
- time_t expires; /* Expiration time from Expires: header. */
- TOKEN token;
-};
-
-#endif /* INN_TDX_STRUCTURE_H */
~ian / innduct.git / blobdiff