LIBSTORAGE(3)LIBSTORAGE(3)NAMElibstorage - 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);
void SMprintfiles(FILE *file, TOKEN token, char **xref, int ngroups)
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);
OVADDRESULT 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) rou‐
tines for accessing Usenet articles and related data independent of
particular storage method; this is known as the storage API. The stor‐
age manager's function is to isolate the applications from the individ‐
ual 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 over‐
view data independent of particular overview method. The ``OV'' func‐
tion is to isolate the applications from the individual methods.
All articles passed through the storage API are assumed to be in wire
format. Wire format means ``\CR\LF'' at the end of lines, ``.'' at the
beginning of lines, and ``.\CR\LF'' at the end of article on NNTP
stream are not stripped. This has a performance win when transferring
articles. For the ``tradspool'' method, wire format can be disabled.
This is just for compatibility which is needed by some old tools writ‐
ten 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 string for output.
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 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 speci‐
fied, SMstore uses its value as article's arrival time; otherwise
SMstore uses the current time for it. SMstore returns token type as
type, or returns TOKEN_EMPTY if article is not stored because some
error occurs or simply does not match any uwildmat(3) in storage.conf.
SMstore fails if SM_RDWR has not been 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 a
NULL pointer ARTHANDLE is returned, no articles are left to be queried.
If data of ARTHANDLE is NULL pointer or len of ARTHANDLE is 0, it indi‐
cates 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
internally.
SMcancel removes the article specified with token. It returns true if
cancellation is successful or returns false if not. SMcancel fails if
SM_RDWR has not been 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.
SMprintfiles shows file name or token usable by fastrm(8).
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 frees any resources it has allocated for itself.
SMerrno and SMerrorstr indicate the reason of the last error concerning
storage manager.
OVopen calls the setup function for configured method which is speci‐
fied as ``ovmethod'' in inn.conf. 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 sets 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 that specified newsgroup is being
added.
OVgroupdel informs overview method that specified newsgroup is being
removed.
OVadd stores an overview data.
OVcancel requests the overview method delete overview data specified
with token.
OVopensearch requests the overview method 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 first time; subsequent OVsearch calls should use the handle
returned by the previous call to 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. Note that the retrieved data is not
neccessarily null-terminated; you should only rely on len octets of
overview data being present.
OVclosesearch frees all resources which have been 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 purges overview data if the
article no longer exists. If ``groupbaseexpiry'' in inn.conf is true,
OVexpiregroup also expires articles.
OVclose frees all resources which are used by the overview method.
HISTORY
Written by Katsuhiro Kondou <kondou@nec.co.jp> for InterNetNews. This
is revision 6124, dated 2003-01-14.
SEE ALSOexpire(8), inn.conf(5), storage.conf(5).
LIBSTORAGE(3)
