LIBSTORAGE

NAME

libstorage - InterNetNews Storage API library routines

SYNOPSIS


#include "storage.h"

BOOL IsToken(const char *text);

char *TokenToText(const TOKEN token);

TOKEN TextToToken(const char *text);

BOOL SMsetup(SMSETUP type, void *value);

BOOL SMinit(void);

TOKEN SMstore(const ARTHANDLE article);

ARTHANDLE *SMretrieve(const TOKEN token, const RETRTYPE amount);

ARTHANDLE *SMnext(const ARTHANDLE *article, const RETRTYPE amount);

void SMfreearticle(ARTHANDLE *article);

BOOL SMcancel(TOKEN token);

BOOL SMprobe(PROBETYPE type, TOKEN *token, void *value);

BOOL SMflushcacheddata(FLUSHTYPE type);

void SMshutdown(void);

int SMerrno;
char *SMerrorstr;

#include "ov.h"

BOOL OVopen(int mode);

BOOL OVctl(OVCTLTYPE type, void *val);

BOOL OVgroupstats(char *group, int *lo, int *hi, int *count, int *flag);

BOOL OVgroupadd(char *group, ARTNUM lo, ARTNUM hi, char *flag);

BOOL OVgroupdel(char *group);

BOOL OVadd(TOKEN token, char *data, int len, time_t arrived);

BOOL OVcancel(TOKEN token);

void *OVopensearch(char *group, int low, int high);

BOOL OVsearch(void *handle, ARTNUM *artnum, char **data, int *len, TOKEN *token, time_t *arrived);

void OVclosesearch(void *handle);

BOOL OVgetartinfo(char *group, ARTNUM artnum, char **data, int *len, TOKEN *token);

BOOL OVexpiregroup(char *group, int *lo);

typedef struct _OVGE {
    BOOL        delayrm;
    BOOL        usepost;
    BOOL        quiet;
    BOOL        keep;
    BOOL        earliest;
    BOOL        ignoreselfexpire;
    char        *filename;
    time_t      now;
    float       timewarp;
} OVGE;

void OVclose(void);

DESCRIPTION

Libstorage is a library of common utility (the storage manager) routines for accessing Usenet articles and related data independent of particular storage method, and this is called storage api. The storage manager's function is to isolate the applications from the individual methods and make the policy decisions as to which storage method should be called to store an article.

One of the core concepts in the storage api is that articles are not manipulated using the message-id or article number, but rather a token that uniquely identifies the article to the method that stored it. This may seem to be redundant since the message-id already is a unique identifier for the article, however, since the storage method generates the token, it can encode all the information it needs to locate the article in the token.

``OV'' is a common utility routines for accessing newsgroups and overview data independent of particular overview method. The ``OV'' function is to isolate the applications from the individual methods.

All articles passed through storage api are assumed to be wire formatted. Wire formatted means that ``\CR\LF'' at the end of lines, ``.'' at the beginnig of lines and ``.\CR\LF'' at the end of article on nntp stream are not stripped. This has performance win when transferring articles. For ``tradspool'' method, wire format can be disabled. This is just for compatibility which is needed by some old tool written for traditional spool.

IsToken checks to see if the text is formatted as a text token string. It returns TRUE if formatted correctly or returns FALSE if not.

TokenToText converts token into text token string.

TextToToken converts text into token.

SMsetup configures some parameters for use by storage manager. Type is one of following.

SM_RDWR              allow read/write open for storage
                     files(default is FALSE)
SM_PREOPEN           open all storage files at startup
                     time and keep them(default is FALSE)

The value is the pointer which tells each type's value. It returns TRUE if setup is successful or returns FALSE if not.

SMinit calls the setup function for all of the configured methods based on SMsetup. This function should be called prior to all other storage api functions which begin with ``SM'' except SMsetup. It returns TRUE if initialization is successful or returns FALSE if not. SMinit returns TRUE, unless all storage methods fail initialization.

SMstore stores an article specified with article. If arrived is specified, SMstore use its value as article's arrival time or SMstore use current time for it. SMstore returns token type as type, or returns TOKEN_EMPTY if article is not stored whichever error occures or simply does not match wildmat(3) in storage.conf(5). SMstore fails if SM_RDWR is not set to true with SMsetup.

SMretrieve retrieves an article specified with token. Amount is the one of following which specifies retrieving type.

RETR_ALL             retrieve whole article
RETR_HEAD            retrieve headers of article
RETR_BODY            retrieve body of article
RETR_STAT            just check to see if article exists

The data area indicated by ARTHANDLE should not be modified.

SMnext is similar in function to SMretrieve except that it is intended for traversing the method's article store sequentially. To start a query, SMnext should be called with a NULL pointer ARTHANDLE. Then SMnext returns ARTHANDLE which should be used for the next query. If NULL pointer ARTHANDLE is returned, no article is left to be queried. If data of ARTHANDLE is NULL pointer or len of ARTHANDLE is 0, it indicates the article may be corrupted and should be cancelled by SMcancel. The data area indicated by ARTHANDLE should not be modified.

SMfreearticle frees all allocated memory used by SMretrieve and SMnext. If SMnext will be called with previously returned ARTHANDLE, SMfreearticle should not be called as SMnext frees allocated memory in itself.

SMcancel removes an article specified with token. It returns TRUE if cancellation is successful or returns FALSE if not. SMcancel fails if SM_RDWR is not set to true with SMsetup.

SMprobe checks the token on PROBETYPE. Type is one of following.

SELFEXPIRE           checks to see if the method of the token
                     has self expire functionality
SMARTNGNUM           gets newsgroup name and article number
                     of the token.

SMflushcacheddata flushes cached data on each storage method. Type is one of following.

SM_HEAD              flushes cached header
SM_CANCELEDART       flushes articles which should be canceled
SM_ALL               flushes all cached data

SMshutdown calls the shutdown for each configured storage method and then free any resources it has allocated for itself.

SMerrno and SMerrorstr indicates the reason of the last error concerning storage manager.

OVopen calls the setup function for configured method which is specified as ``ovmethod'' in inn.conf(5). Mode is constructed from following.

OV_READ              allow read open for overview
                     method
OV_WRITE             allow write open for overview
                     method

This function should be called prior to all other OV functions which begin with ``OV''.

OVctl probes or set some parameters for overview method. Type is one of following.

OVGROUPBASEDEXPIRE   setup how group based expiry is
                     done
OVCUTOFFLOW          do not add overview data, if the
                     data is under lowest article
OVSORT               probe which key is suitable for
                     overview method
OVSPACE              probe overview space usage
OVSTATALL            stat all articles when
                     OVexpiregroup is called

OVgroupstats retrieves specified newsgroup information from overview method.

OVgroupadd informs overview method to specified newsgroup is added.

OVgroupdel informs overview method to specified newsgroup is removed.

OVadd stores an overview data.

OVcancel requests overview method to delete an overview data specified with token.

OVopensearch requests overview method to prepare overview data retrieval. The request range is determined by low and high.

OVsearch retrieves information; article number, overview data or arrival time. OVsearch should be called with NULL handle when it is the 1st time. And subsequent OVsearch should be called with the handle which is got at preveous OVsearch. OVsearch returns TRUE, unless it reaches high which is specified by OVopensearch. Retrieved overview data are sorted by article number, and len is 0 if there is no overview data for article.

OVclosesearch frees all resources which is allocated by OVopensearch.

OVgetartinfo retrieves overview data and token specified with artnum.

OVexpiregroup expires overview data for the newsgroup. OVexpiregroup checks the existense of the article and purge overview data if it's gone. If ``groupbaseexpiry'' in inn.conf is true, OVexpiregroup also expires articles.

OVclose frees all resources which is used by overview method.

HISTORY

Written by Katsuhiro Kondou <kondou@nec.co.jp> for InterNetNews. This is revision 1.12.2.2, dated 2000/09/05.