9 libsolv-pool - Libsolv's pool object
16 A no-purpose pointer free to use for the library user. Freeing the pool
17 simply discards the pointer.
20 The pool of unified strings.
23 The pool of unified relation dependencies.
26 Number of allocated relation dependencies.
29 The array of repository pointers, indexed by repository Id.
32 Number of allocated repository array elements, i.e. the size
36 Number of used (i.e. non-zero) repository array elements.
39 Pointer to the repo holding the installed packages. You are free to read
40 this attribute, but you should use pool_set_installed() if you want to
43 *Solvable *solvables*::
44 The array of Solvable objects.
47 Number of Solvable objects, i.e. the size of the solvables array. Note
48 that the array may contain freed solvables, in that case the repo pointer
49 of the solvable will be zero.
52 The distribution type of your system, e.g. DISTTYPE_DEB. You are free to
53 read this attribute, but you should use pool_setdisttype() if you want to
56 *Id *whatprovidesdata*::
57 Multi-purpose Id storage holding zero terminated arrays of Ids.
58 pool_whatprovides() returns an offset into this data.
61 Optional bitmap that can make the library ignore solvables. If a bitmap is
62 set, only solvables that have a set bit in the bitmap at their Id are
66 A mask that defines which debug events should be reported.
67 pool_setdebuglevel() sets this mask.
70 An object storing some position in the repository data. Functions like
71 dataiterator_set_pos() set this object, accessing data with a pseudo
72 solvable Id of SOLVID_POS uses it.
75 A queue where fixed solver jobs can be stored. This jobs are automatically
76 added when solver_solve() is called, they are useful to store configuration
77 data like which packages should be multiversion installed.
79 Creation and Destruction
80 ------------------------
84 Create a new instance of a pool.
86 void pool_free(Pool *pool);
88 Free a pool and all of the data it contains, e.g. the solvables,
89 repositories, strings.
92 Debugging and error reporting
93 -----------------------------
98 Report the error and call ``exit(1)'' afterwards. You cannot mask this
99 level. Reports to stderr instead of stdout.
102 Used to report errors. Reports to stderr instead of stdout.
105 Used to report warnings.
108 Used to report statistical data.
110 *SOLV_DEBUG_RULE_CREATION*::
111 Used to report information about the solver's creation of rules.
113 *SOLV_DEBUG_PROPAGATE*::
114 Used to report information about the solver's unit rule propagation
117 *SOLV_DEBUG_ANALYZE*::
118 Used to report information about the solver's learnt rule generation
121 *SOLV_DEBUG_UNSOLVABLE*::
122 Used to report information about the solver dealing with conflicting
125 *SOLV_DEBUG_SOLUTIONS*::
126 Used to report information about the solver creating solutions to solve
129 *SOLV_DEBUG_POLICY*::
130 Used to report information about the solver searching for an optimal
133 *SOLV_DEBUG_RESULT*::
134 Used by the debug functions to output results.
137 Used to report information about the job rule generation process.
139 *SOLV_DEBUG_SOLVER*::
140 Used to report information about what the solver is currently
143 *SOLV_DEBUG_TRANSACTION*::
144 Used to report information about the transaction generation and
147 *SOLV_DEBUG_TO_STDERR*::
148 Write debug messages to stderr instead of stdout.
152 void pool_debug(Pool *pool, int type, const char *format, ...);
154 Report a message of the type _type_. You can filter debug messages by
155 setting a debug mask.
157 void pool_setdebuglevel(Pool *pool, int level);
159 Set a predefined debug mask. A higher level generally means more bits in
160 the mask are set, thus more messages are printed.
162 void pool_setdebugmask(Pool *pool, int mask);
164 Set the debug mask to filter debug messages.
166 int pool_error(Pool *pool, int ret, const char *format, ...);
168 Set the pool's error string. The _ret_ value is simply used as a
169 return value of the function so that you can write code like
170 +return pool_error(...);+. If the debug mask contains the *SOLV_ERROR*
171 bit, pool_debug() is also called with the message and type *SOLV_ERROR*.
173 extern char *pool_errstr(Pool *pool);
175 Return the current error string stored in the pool. Like with the libc's
176 errno value, the string is only meaningful after a function returned an
179 void pool_setdebugcallback(Pool *pool, void (*debugcallback)(Pool *, void *data, int type, const char *str), void *debugcallbackdata);
181 Set a custom debug callback function. Instead of writing to stdout or
182 stderr, the callback function will be called.
191 Used for systems with use rpm as low level package manager.
194 Used for systems with use dpkg as low level package manager.
197 Used for systems with use the arch linux package manager.
200 Used for systems with use haiku packages.
202 *POOL_FLAG_PROMOTEEPOCH*::
203 Promote the epoch of the providing dependency to the requesting
204 dependency if it does not contain an epoch. Used at some time
205 in old rpm versions, modern systems should never need this.
207 *POOL_FLAG_FORBIDSELFCONFLICTS*::
208 Disallow the installation of packages that conflict with themselves.
209 Debian always allows self-conflicting packages, rpm used to forbid
210 them but switched to also allowing them recently.
212 *POOL_FLAG_OBSOLETEUSESPROVIDES*::
213 Make obsolete type dependency match against provides instead of
214 just the name and version of packages. Very old versions of rpm
215 used the name/version, then it got switched to provides and later
216 switched back again to just name/version.
218 *POOL_FLAG_IMPLICITOBSOLETEUSESPROVIDES*::
219 An implicit obsoletes is the internal mechanism to remove the
220 old package on an update. The default is to remove all packages
221 with the same name, rpm-5 switched to also removing packages
222 providing the same name.
224 *POOL_FLAG_OBSOLETEUSESCOLORS*::
225 Rpm's multilib implementation (used in RedHat and Fedora)
226 distinguishes between 32bit and 64bit packages (the terminology
227 is that they have a different color). If obsoleteusescolors is
228 set, packages with different colors will not obsolete each other.
230 *POOL_FLAG_IMPLICITOBSOLETEUSESCOLORS*::
231 Same as POOL_FLAG_OBSOLETEUSESCOLORS, but used to find out if
232 packages of the same name can be installed in parallel. For
233 current Fedora systems, POOL_FLAG_OBSOLETEUSESCOLORS should be
234 false and POOL_FLAG_IMPLICITOBSOLETEUSESCOLORS should be true
235 (this is the default if FEDORA is defined when libsolv is
238 *POOL_FLAG_NOINSTALLEDOBSOLETES*::
239 New versions of rpm consider the obsoletes of installed packages
240 when checking for dependency, thus you may not install a package
241 that is obsoleted by some other installed package, unless you
242 also erase the other package.
244 *POOL_FLAG_HAVEDISTEPOCH*::
245 Mandriva added a new field called distepoch that gets checked in
246 version comparison if the epoch/version/release of two packages
249 *POOL_FLAG_NOOBSOLETESMULTIVERSION*::
250 If a package is installed in multiversionmode, rpm used to ignore
251 both the implicit obsoletes and the obsolete dependency of a
252 package. This was changed to ignoring just the implicit obsoletes,
253 thus you may install multiple versions of the same name, but
254 obsoleted packages still get removed.
256 *POOL_FLAG_ADDFILEPROVIDESFILTERED*::
257 Make the addfileprovides method only add files from the standard
258 locations (i.e. the ``bin'' and ``etc'' directories). This is
259 useful if you have only few packages that use non-standard file
260 dependencies, but you still wand the fast speed that addfileprovides()
265 void pool_setdisttype(Pool *pool, int disttype);
267 Set the package type of your system. The disttype is used for example
268 to define package comparison semantics. Libsolv's default disttype
269 should match the package manager of your system, so you only need to
270 use this function if you want to use the library to solve packaging
271 problems for different systems.
273 int pool_set_flag(Pool *pool, int flag, int value);
275 Set a flag to a new value. Returns the old value of the flag.
277 int pool_get_flag(Pool *pool, int flag);
279 Get the value of a pool flag. See the constants section about the meaning
282 void pool_set_rootdir(Pool *pool, const char *rootdir);
284 Set a specific root directory. Some library functions support a flag that
285 tells the function to prepend the rootdir to file and directory names.
287 const char *pool_get_rootdir(Pool *pool);
289 Return the current value of the root directory.
291 char *pool_prepend_rootdir(Pool *pool, const char *dir);
293 Prepend the root directory to the _dir_ argument string. The returned
294 string has been newly allocated and needs to be freed after use.
296 char *pool_prepend_rootdir_tmp(Pool *pool, const char *dir);
298 Same as pool_prepend_rootdir, but uses the pool's temporary space for
301 void pool_set_installed(Pool *pool, Repo *repo);
303 Set which repository should be treated as the ``installed'' repository,
304 i.e. the one that holds information about the installed packages.
306 void pool_set_languages(Pool *pool, const char **languages, int nlanguages);
308 Set the language of your system. The library provides lookup functions that
309 return localized strings, for example for package descriptions. You can
310 set an array of languages to provide a fallback mechanism if one language
313 void pool_setarch(Pool *pool, const char *arch);
315 Set the architecture of your system. The architecture is used to determine
316 which packages are installable and which packages cannot be installed.
317 The _arch_ argument is normally the ``machine'' value of the ``uname''
320 void pool_setarchpolicy(Pool *, const char *);
322 Set the architecture policy for your system. This is the general version
323 of pool_setarch (in fact pool_setarch calls pool_setarchpolicy internally).
324 See the section about architecture policies for more information.
326 void pool_addvendorclass(Pool *pool, const char **vendorclass);
328 Add a new vendor equivalence class to the system. A vendor equivalence class
329 defines if an installed package of one vendor can be replaced by a package
330 coming from a different vendor. The _vendorclass_ argument must be a
331 NULL terminated array of strings. See the section about vendor policies for
334 void pool_setvendorclasses(Pool *pool, const char **vendorclasses);
336 Set all allowed vendor equivalences. The vendorclasses argument must be an
337 NULL terminated array consisting of all allowed classes concatenated.
338 Each class itself must be NULL terminated, thus the last class ends with
339 two NULL elements, one to finish the class and one to finish the list
342 void pool_set_custom_vendorcheck(Pool *pool, int (*vendorcheck)(Pool *, Solvable *, Solvable *));
344 Define a custom vendor check mechanism. You can use this if libsolv's
345 internal vendor equivalence class mechanism does not match your needs.
347 void pool_setloadcallback(Pool *pool, int (*cb)(Pool *, Repodata *, void *), void *loadcbdata);
349 Define a callback function that gets called when repository metadata needs
350 to be loaded on demand. See the section about on demand loading in the
351 libsolv-repodata manual.
353 void pool_setnamespacecallback(Pool *pool, Id (*cb)(Pool *, void *, Id, Id), void *nscbdata);
355 Define a callback function to implement custom namespace support. See the
356 section about namespace dependencies.
364 The Id of the empty string, it is always Id 1.
367 Represents a ``<'' relation.
370 Represents a ``='' relation.
373 Represents a ``>'' relation. You can use combinations of REL_GT, REL_EQ,
374 and REL_LT or-ed together to create any relation you like.
377 A boolean AND operation, the ``name'' and ``evr'' parts of the relation can
378 be two sub-dependencies. Packages must match both parts of the dependency.
381 A boolean OR operation, the ``name'' and ``evr'' parts of the relation can
382 be two sub-dependencies. Packages can match any part of the dependency.
385 Like REL_AND, but packages mast match both dependencies simultaneously. See
386 the section about boolean dependencies about more information.
389 A special namespace relation. See the section about namespace dependencies
390 for more information.
393 A architecture filter dependency. The ``name'' part of the relation is a
394 sub-dependency, the ``evr'' part is the Id of an architecture that the
395 matching packages must have (note that this is an exact match ignoring
396 architecture policies).
399 An internal file conflict dependency used to represent file conflicts. See
400 the pool_add_fileconflicts_deps() function.
403 A conditional dependency, the ``name'' sub-dependency is only considered if
404 the ``evr'' sub-dependency is fulfilled. See the section about boolean
405 dependencies about more information.
408 A compat dependency used in Haiku to represent version ranges. The
409 ``name'' part is the actual version, the ``evr'' part is the backwards
410 compatibility version.
413 Id pool_str2id(Pool *pool, const char *str, int create);
415 Add a string to the pool of unified strings, returning the Id of the string.
416 If _create_ is zero, new strings will not be added to the pool, instead
419 Id pool_strn2id(Pool *pool, const char *str, unsigned int len, int create);
421 Same as pool_str2id, but only _len_ characters of the string are used. This
422 can be used to add substrings to the pool.
424 Id pool_rel2id(Pool *pool, Id name, Id evr, int flags, int create);
426 Create a relational dependency from to other dependencies, _name_ and _evr_,
427 and a _flag_. See the *REL_* constants for the supported flags. As with
428 pool_str2id, _create_ defines if new dependencies will get added or Id zero
429 will be returned instead.
431 Id pool_id2langid(Pool *pool, Id id, const char *lang, int create);
433 Attach a language suffix to a string Id. This function can be used to
434 create language keyname Ids from keynames, it is functional equivalent
435 to converting the _id_ argument to a string, adding a ``:'' character
436 and the _lang_ argument to the string and then converting the result back
439 const char *pool_id2str(const Pool *pool, Id id);
441 Convert an Id back into a string. If the Id is a relational Id, the
442 ``name'' part will be converted instead.
444 const char *pool_id2rel(const Pool *pool, Id id);
446 Return the relation string of a relational Id. Returns an empty string if
447 the passed Id is not a relation.
449 const char *pool_id2evr(const Pool *pool, Id id);
451 Return the ``evr'' part of a relational Id as string. Returns an empty
452 string if the passed Id is not a relation.
454 const char *pool_dep2str(Pool *pool, Id id);
456 Convert an Id back into a string. If the passed Id belongs to a relation,
457 a string representing the relation is returned. Note that in that case
458 the string is allocated on the pool's temporary space.
460 void pool_freeidhashes(Pool *pool);
462 Free the hashes used to unify strings and relations. You can use this
463 function to save memory if you know that you will no longer create new
464 strings and relations.
470 Solvable *pool_id2solvable(const Pool *pool, Id p);
472 Convert a solvable Id into a pointer to the solvable data. Note that the
473 pointer may become invalid if new solvables are created or old solvables
474 deleted, because the array storing all solvables may get reallocated.
476 const char *pool_solvid2str(Pool *pool, Id p);
478 Return a string representing the solvable with the Id _p_. The string will
479 be some canonical representation of the solvable, usually a combination of
480 the name, the version, and the architecture.
482 const char *pool_solvable2str(Pool *pool, Solvable *s);
484 Same as pool_solvid2str, but instead of the Id, a pointer to the solvable
493 Compare all parts of the version, treat missing parts as empty strings.
495 *EVRCMP_MATCH_RELEASE*::
496 A special mode for rpm version string matching. If a version misses a
497 release part, it matches all releases. In that case the special values
498 ``-2'' and ``2'' are returned, depending on which of the two versions
499 did not have a release part.
502 A generic match, missing parts always match.
504 *EVRCMP_COMPARE_EVONLY*::
505 Only compare the epoch and the version parts, ignore the release part.
508 int pool_evrcmp(const Pool *pool, Id evr1id, Id evr2id, int mode);
510 Compare two version Ids, return -1 if the first version is less then the
511 second version, 0 if they are identical, and 1 if the first version is
512 bigger than the second one.
514 int pool_evrcmp_str(const Pool *pool, const char *evr1, const char *evr2, int mode);
516 Same as pool_evrcmp(), but uses strings instead of Ids.
518 int pool_evrmatch(const Pool *pool, Id evrid, const char *epoch, const char *version, const char *release);
520 Match a version Id against an epoch, a version and a release string. Passing
521 NULL means that the part should match everything.
523 int pool_match_dep(Pool *pool, Id d1, Id d2);
525 Returns ``1'' if the dependency _d1_ (the provider) is matched by the
526 dependency _d2_, otherwise ``0'' is returned. For two dependencies to
527 match, both the ``name'' parts must match and the version range described
528 by the ``evr'' parts must overlap.
530 int pool_match_nevr(Pool *pool, Solvable *s, Id d);
532 Like pool_match_dep, but the provider is the "self-provides" dependency
533 of the Solvable _s_, i.e. the dependency ``s->name = s->evr''.
538 void pool_createwhatprovides(Pool *pool);
540 Create a index that maps dependency Ids to sets of packages that provide the
543 void pool_freewhatprovides(Pool *pool);
545 Free the whatprovides index to save memory.
547 Id pool_whatprovides(Pool *pool, Id d);
549 Return an offset into the Pool's whatprovidesdata array. The solvables with
550 the Ids stored starting at that offset provide the dependency _d_. The
551 solvable list is zero terminated.
553 Id *pool_whatprovides_ptr(Pool *pool, Id d);
555 Instead of returning the offset, return the pointer to the Ids stored at
556 that offset. Note that this pointer has a very limit validity time, as any
557 call that adds new values to the whatprovidesdata area may reallocate the
560 Id pool_queuetowhatprovides(Pool *pool, Queue *q);
562 Add the contents of the Queue _q_ to the end of the whatprovidesdata array,
563 returning the offset into the array.
565 void pool_addfileprovides(Pool *pool);
567 Some package managers like rpm allow dependencies on files contained in
568 other packages. To allow libsolv to deal with those dependencies in an
569 efficient way, you need to call the addfileprovides method after creating
570 and reading all repositories. This method will scan all dependency for file
571 names and than scan all packages for matching files. If a filename has been
572 matched, it will be added to the provides list of the corresponding
575 void pool_addfileprovides_queue(Pool *pool, Queue *idq, Queue *idqinst);
577 Same as pool_addfileprovides, but the added Ids are returned in two Queues,
578 _idq_ for all repositories except the one containing the ``installed''
579 packages, _idqinst_ for the latter one. This information can be stored in
580 the meta section of the repositories to speed up the next time the
581 repository is loaded and addfileprovides is called
583 void pool_flush_namespaceproviders(Pool *pool, Id ns, Id evr);
585 Clear the cache of the providers for namespace dependencies matching
586 namespace _ns_. If the _evr_ argument is non-zero, the namespace dependency
587 for exactly that dependency is cleared, otherwise all matching namespace
588 dependencies are cleared. See the section about Namespace dependencies
589 for further information.
591 void pool_add_fileconflicts_deps(Pool *pool, Queue *conflicts);
593 Some package managers like rpm report conflicts when a package installation
594 overwrites a file of another installed package with different content. As
595 file content information is not stored in the repository metadata, those
596 conflicts can only be detected after the packages are downloaded. Libsolv
597 provides a function to check for such conflicts, pool_findfileconflicts().
598 If conflicts are found, they can be added as special *REL_FILECONFLICT*
599 provides dependencies, so that the solver will know about the conflict when
605 char *pool_alloctmpspace(Pool *pool, int len);
607 Allocate space on the pool's temporary space area. This space has a limited
608 lifetime, it will be automatically freed after a fixed amount (currently
609 16) of other pool_alloctmpspace() calls are done.
611 void pool_freetmpspace(Pool *pool, const char *space);
613 Give the space allocated with pool_alloctmpspace back to the system. You
614 do not have to use this function, as the space is automatically reclaimed,
615 but it can be useful to extend the lifetime of other pointers to the pool's
616 temporary space area.
618 const char *pool_bin2hex(Pool *pool, const unsigned char *buf, int len);
620 Convert some binary data to hexadecimal, returning a string allocated in
621 the pool's temporary space area.
623 char *pool_tmpjoin(Pool *pool, const char *str1, const char *str2, const char *str3);
625 Join three strings and return the result in the pool's temporary space
626 area. You can use NULL arguments if you just want to join less strings.
628 char *pool_tmpappend(Pool *pool, const char *str1, const char *str2, const char *str3);
630 Like pool_tmpjoin(), but if the first argument is the last allocated space
631 in the pool's temporary space area, it will be replaced with the result of
632 the join and no new temporary space slot will be used. Thus you can join
633 more then three strings by a combination of one pool_tmpjoin() and multiple
634 pool_tmpappend() calls. Note that the _str1_ pointer is no longer usable
643 Use the data position stored in the pool for the lookup instead of looking
644 up the data of a solvable.
647 Use the data stored in the meta section of a repository (or repodata
648 area) instead of looking up the data of a solvable. This constant does
649 not work for the pool's lookup functions, use it for the repo's or
650 repodata's lookup functions instead. It's just listed for completeness.
653 const char *pool_lookup_str(Pool *pool, Id solvid, Id keyname);
655 Return the string value stored under the attribute _keyname_ in solvable
658 unsigned long long pool_lookup_num(Pool *pool, Id solvid, Id keyname, unsigned long long notfound);
660 Return the 64bit unsigned number stored under the attribute _keyname_ in
661 solvable _solvid_. If no such number is found, the value of the _notfound_
662 argument is returned instead.
664 Id pool_lookup_id(Pool *pool, Id solvid, Id keyname);
666 Return the Id stored under the attribute _keyname_ in solvable _solvid_.
668 int pool_lookup_idarray(Pool *pool, Id solvid, Id keyname, Queue *q);
670 Fill the queue _q_ with the content of the Id array stored under the
671 attribute _keyname_ in solvable _solvid_. Returns ``1'' if an array was
672 found, otherwise the queue will be empty and ``0'' will be returned.
674 int pool_lookup_void(Pool *pool, Id solvid, Id keyname);
676 Returns ``1'' if a void value is stored under the attribute _keyname_ in
677 solvable _solvid_, otherwise ``0''.
679 const char *pool_lookup_checksum(Pool *pool, Id solvid, Id keyname, Id *typep);
681 Return the checksum that is stored under the attribute _keyname_ in
682 solvable _solvid_. The type of the checksum will be returned over the
683 _typep_ pointer. If no such checksum is found, NULL will be returned and
684 the type will be set to zero. Note that the result is stored in the Pool's
685 temporary space area.
687 const unsigned char *pool_lookup_bin_checksum(Pool *pool, Id solvid, Id keyname, Id *typep);
689 Return the checksum that is stored under the attribute _keyname_ in
690 solvable _solvid_. Returns the checksum as binary data, you can use the
691 returned type to calculate the length of the checksum. No temporary space
694 const char *pool_lookup_deltalocation(Pool *pool, Id solvid, unsigned int *medianrp);
696 This is a utility lookup function to return the delta location for a delta
697 rpm. As solvables cannot store deltas, you have to use SOLVID_POS as
698 argument and set the Pool's datapos pointer to point to valid delta rpm
701 void pool_search(Pool *pool, Id solvid, Id keyname, const char *match, int flags, int (*callback)(void *cbdata, Solvable *s, Repodata *data, Repokey *key, KeyValue *kv), void *cbdata);
703 Perform a search on all data stored in the pool. You can limit the search
704 area by using the _solvid_ and _keyname_ arguments. The values can be
705 optionally matched against the _match_ argument, use NULL if you do not
706 want this matching. See the Dataiterator manpage about the possible matches
707 modes and the _flags_ argument. For all (matching) values, the callback
708 function is called with the _cbdata_ callback argument and the data
709 describing the value.
712 Job and Selection functions
713 ---------------------------
714 A Job consists of two Ids, _how_ and _what_. The _how_ part describes the
715 action, the job flags, and the selection method while the _what_ part is
716 in input for the selection. A Selection is a queue consisting of multiple
717 jobs (thus the number of elements in the queue must be a multiple of two).
718 See the Solver manpage for more information about jobs.
720 const char *pool_job2str(Pool *pool, Id how, Id what, Id flagmask);
722 Convert a job into a string. Useful for debugging purposes. The _flagmask_
723 can be used to mask the flags of the job, use ``0'' if you do not want to
724 see such flags, ``-1'' to see all flags, or a combination of the flags
727 void pool_job2solvables(Pool *pool, Queue *pkgs, Id how, Id what);
729 Return a list of solvables that the specified job selects.
731 int pool_isemptyupdatejob(Pool *pool, Id how, Id what);
733 Return ``1'' if the job is an update job that does not work with any
734 installed package, i.e. the job is basically a no-op. You can use this
735 to turn no-op update jobs into install jobs (as done by package managers
738 const char *pool_selection2str(Pool *pool, Queue *selection, Id flagmask);
740 Convert a selection into a string. Useful for debugging purposes. See the
741 pool_job2str() function for the _flagmask_ argument.
746 void pool_freeallrepos(Pool *pool, int reuseids);
748 Free all repos from the pool (including all solvables). If _reuseids_ is
749 true, all Ids of the solvables are free to be reused the next time
750 solvables are created.
752 void pool_clear_pos(Pool *pool);
754 Clear the data position stored in the pool.
757 Architecture Policies
758 ---------------------
759 An architecture policy defines a list of architectures that can be
760 installed on the system, and also the relationship between them (i.e. the
761 ordering). Architectures can be delimited with three different characters:
764 No relationship between the architectures. A package of one architecture
765 can not be replaced with one of the other architecture.
768 The first architecture is better than the second one. An installed package
769 of the second architecture may be replaced with one from the first
770 architecture and vice versa. The solver will select the better architecture
771 if the versions are the same.
774 The two architectures are freely exchangeable. Used to define aliases
777 An example would be \'+x86_64:i686=athlon>i586+'. This means that x86_64
778 packages can only be replaced by other x86_64 packages, i686 packages
779 can be replaced by i686 and i586 packages (but i686 packages will be
780 preferred) and athlon is another name for the i686 architecture.
782 You can turn off the architecture replacement checks with the Solver's
783 SOLVER_FLAG_ALLOW_ARCHCHANGE flag.
787 Different vendors often compile packages with different features, so
788 Libsolv only replace installed packages of one vendor with packages coming
789 from the same vendor. Also, while the version of a package is normally
790 defined by the upstream project, the release part of the version is
791 set by the vendor's package maintainer, so it's not meaningful to
792 do version comparisons for packages coming from different vendors.
794 Vendor in this case means the SOLVABLE_VENDOR string stored in each
795 solvable. Sometimes a vendor changes names, or multiple vendors form a
796 group that coordinate their package building, so libsolv offers a way
797 to define that a group of vendors are compatible. You do that be
798 defining vendor equivalence classes, packages from a vendor from
799 one class may be replaced with packages from all the other vendors
802 There can be multiple equivalence classes, the set of allowed vendor
803 changes for an installed package is calculated by building the union
804 of all of the equivalence classes the vendor of the installed package
807 You can turn off the architecture replacement checks with the Solver's
808 SOLVER_FLAG_ALLOW_VENDORCHANGE flag.
813 Boolean Dependencies allow to build complex expressions from simple
814 dependencies. While rpm does not support boolean expressions in
815 dependencies and debian only allows an "OR" expression, libsolv
816 allows to arbitrary complex expressions. The following basic types
820 The expression is true if either the first dependency or the second
821 one is true. This is useful for package dependencies like ``Requires'',
822 where you can specify that either one of the packages need to be
826 The expression is true if both dependencies are true. The packages
827 fulfilling the dependencies may be different, i.e.
828 ``Supplements: perl AND python'' is true if both a package providing
829 perl and a package providing python are installed. The solver currently
830 only supports REL_AND in Supplements/Enhances dependencies, in other
831 types of dependencies it gets treated as REL_WITH.
834 The expression is true if both dependencies are true and are fulfilled by
835 the same package. Thus ``Supplements: perl AND python'' would only be true
836 if a package is installed that provides both dependencies (some kind
837 of multi-language interpreter).
840 The expression is true if the first dependency is true or the second
841 dependency is false. Libsolv currently does not support this type of
842 dependency in the solver code.
844 Each sub-dependency of a boolean dependency can in turn be a boolean
845 dependency, so you can chain them to create complex dependencies.
848 Namespace Dependencies
849 ----------------------
850 Namespace dependencies can be used to implement dependencies on
851 attributes external to libsolv. An example would be a dependency
852 on the language set by the user. This types of dependencies are
853 usually only used for ``Conflicts'' or ``Supplements'' dependencies,
854 as the underlying package manager does not know how to deal with
857 If the library needs to evaluate a namespace dependency, it calls
858 the namespace callback function set in the pool. The callback
859 function can return a set of packages that ``provide'' the
860 dependency. If the dependency is provided by the system, the
861 returned set should consist of just the system solvable (Solvable
864 The returned set of packages must be returned as offset into
865 the whatprovidesdata array. You can use the pool_queuetowhatprovides
866 function to convert a queue into such an offset. To ease programming
867 the callback function, the return values ``0'' and ``1'' are not
868 interpreted as an offset. ``0'' means that no package is in the
869 return set, ``1'' means that just the system solvable is in the set.
871 The returned set is cached, so that for each namespace dependency
872 the callback is just called once. If you need to flush the cache (maybe
873 because the user has selected a different language), use the
874 pool_flush_namespaceproviders() function.
879 Michael Schroeder <mls@suse.de>