af_cache(3) Attribute Filesystem (AtFS) af_cache(3)NAME
af_savecache, af_cachesize - AtFS derived object cache handling
SYNOPSIS
#include <atfs.h>
int af_savecache (Af_key *busyAso, Af_key* cachedAso, char *attr, int mode)
int af_cachesize (char path, int totalMax, int maxPerName, int maxPerGivenAttr);
DESCRIPTION
af_savecache copies a busy attributed software object (busyAso) to a derived object cache. A key for the resulting cached ASO is returned
in the buffer cachedAso. Derived object caches are intended to hold derived objects that can be reproduced at any time. Reproducibility is
important, because cached ASOs may be deleted automatically due to storage limitations for derived object caches. A cache allows a certain
number of versions per name (see function af_cachesize described below) to be stored. When this number is reached, each time a new version
arrives, the oldest version (access date) gets cleaned out.
The strategy of cleaning out old versions when space is needed for new ones is influenced by the attr argument. When this is given af_save-
cache searches for cached versions (with the same name as the new one) carrying the given attribute. If it finds one or more such versions,
the oldest (access date) of them will be eliminated.
The mode argument may have one of the following values
AF_STORE_COMPLETE
(default) The cached file is stored unmodified.
AF_STORE_COMPRESSED
The cached file will be stored in a compressed format.
ASOs that are saved in derived object caches do not automatically get a version number. By means of af_svnum (manual page af_version(3))
you can attach any version number to an ASO stored in a derived object cache.
af_cachesize defines the size strategy of the cache in directory path. It sets the maximum cache size for the whole directory (totalMax),
the maximum number of versions per name (maxPerName), and the number of versions allowed simultaneously carrying the elimination attribute
(see before). A value less or equal zero given for any of the arguments of af_cachesize will cause this argument to be ignored.
DIAGNOSTICS
Upon error, -1 is returned and af_errno is set to the corresponding error number.
BUGS
Compression of cached files (mode AF_STORE_COMPRESSED) is not yet supported.
af_cachesize cannot shrink derived object caches yet. Values given must be greater or equal the prevoius size.
AtFS-1.71 Mon Jul 19 18:19:37 1993 af_cache(3)
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af_version(3) Attribute Filesystem (AtFS) af_version(3)NAME
af_saverev, af_newgen, af_setbusy, af_sstate, af_svnum - version control in AtFS
SYNOPSIS
#include <atfs.h>
int af_saverev (Af_key *busyAso, Af_key *saveAso, int generation, int storeType)
int af_newgen (Af_key *aso, Af_key *newAso)
int af_setbusy (Af_key *busyAso, Af_key *aso, Af_key *prevAso)
int af_sstate (Af_key *aso, int state)
int af_svnum (Af_key *aso, int gen, int rev)
int af_predsucc (Af_key *inAso, int mode, Af_key *outAso)
DESCRIPTION
af_saverev makes a copy of the ASO identified by busyAso. This new ASO gets the status saved and a version number according to the follow-
ing scheme:
The initial revision is numbered by generation number 1 and revision number 0. All other saved versions get version numbers built
from these of their predecessors by preserving the generation number and increasing the revision number by 1.
Usually, versions are added to the most recent generation. This is indicated by giving the generation parameter AF_LASTVERS. It is also
possible to add the new version to an older generation, indicated by an explicit generation number. In this case, the predecessor of the
new version is the most recent version of the named generation and the version number is built accordingly.
The storeType argument says, whether the new version shall be stored as delta (difference) to its predecessor version or completely. Valid
values are AF_STORE_DELTA (default) and AF_STORE_COMPLETE.
All attributes except version status and version number (including user defined attributes) are inherited from the busy version. The key
of the generated ASO is returned in saveAso. Use af_dropkey to free the allocated memory associated with saveAso.
Creating a new version in the most recent generation of a history requires reserving the update permissions by setting a lock on the most
recent version (see af_lock(3)). For adding a new version to an old generation, a version lock on the most recent version of the concerned
generation is needed. Subsequent calls of af_saverev for the same object history each need a new lock, as the most recent version becomes
a new one with every call of af_saverev.
af_newgen opens a new generation in a object history. The last saved version will be duplicated. This creates a new ASO, that is numbered
by a new generation number (increased by 1) and the initial revision number (0). All other attributes remain unchanged. af_newgen requires
a lock (see af_lock(3)) set on the ASO specified by aso.
With af_setbusy an application can inform AtFS, that the data file of a busy version (a busy versions data always sits in a UNIX file) has
been exchanged. This is usually the case, after having reinstalled an old version to be basis for further development. The argument aso
denotes the version, from which the new contents of the busy version was taken. busyAso points to the current busy version, if there is
any. It may also be omitted by giving a NULL pointer. af_setbusy returns prevAso the key of the version that previously was set as origin
of the busy version.
af_sstate sets the state of the identified ASO. Only state transitions from one state to the next or previous state (according to the list
below) are allowed. Possible states are:
busy The version is under development and its contents may be changed.
saved The version is saved and may be used for later backup.
proposed
The version has been submitted for publication by the developer but still needs formal approval by a quality assurance board to
become publicly visible and accessible in the official database.
published
The version has passed the formal approval and is now accessible to every member of the project. It is not yet accessed and may
therefore be withdrawn if necessary.
accessed
The version has been published, and is now accessed by some members of the project.
frozen The version may be part of a system configuration that has been released to the outside world. This means it must, under no circum-
stances, be destroyed.
af_svnum sets the version number of the identified ASO to the given generation (gen) and revision (rev) number. The version number of
source objects can only be increased - the version number of derived objects can be set to any value. af_svnum requires a lock (see
af_lock(3)) set on the ASO specified by aso.
af_predsucc returns the predecessor or successor version of inAso. The result is passed in the buffer outAso. The value for the mode param-
eter may be one of the following
AF_LOGICAL_SUCC
logical successor AF_LOGICAL_PRED logical predecessor AF_PHYSICAL_SUCC physical successor AF_PHYSICAL_PRED physical predecessor
SEE ALSO
af_intro (3), af_lock(3)DIAGNOSTICS
Upon error, -1 is returned and af_errno is set to the corresponding error number
BUGS
Due to limitations in the UNIX filesystem, only the creator (author) of a derived object may save ASOs to a derived object cache.
Empty files cannot be inserted in a derived object cache.
The modes AF_LOGICAL_PRED and AF_LOGICAL_SUCC for af_predsucc are not yet impelmented.
AtFS-1.71 Fri Jun 25 14:33:23 1993 af_version(3)