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Diffstat (limited to 'doc/libsolv-pool.txt')
| -rw-r--r-- | doc/libsolv-pool.txt | 454 |
1 files changed, 267 insertions, 187 deletions
diff --git a/doc/libsolv-pool.txt b/doc/libsolv-pool.txt index 018d87b..9740b24 100644 --- a/doc/libsolv-pool.txt +++ b/doc/libsolv-pool.txt @@ -13,8 +13,8 @@ Public Attributes ----------------- *void *appdata*:: -A no-purpose pointer free to use for the library user. Freeing -the pool simply discards the pointer. +A no-purpose pointer free to use for the library user. Freeing the pool +simply discards the pointer. *Stringpool ss*:: The pool of unified strings. @@ -36,46 +36,45 @@ of the repos array. Number of used (i.e. non-zero) repository array elements. *Repo *installed*:: -Pointer to the repo holding the installed packages. You are free -to read this attribute, but you should use pool_set_installed() -if you want to change it. +Pointer to the repo holding the installed packages. You are free to read +this attribute, but you should use pool_set_installed() if you want to +change it. *Solvable *solvables*:: The array of Solvable objects. *int nsolvables*:: -Number of Solvable objects, i.e. the size of the solvables array. -Note that the array may contain freed solvables, in that case -the repo pointer of the solvable will be zero. +Number of Solvable objects, i.e. the size of the solvables array. Note +that the array may contain freed solvables, in that case the repo pointer +of the solvable will be zero. *int disttype*:: -The distribution type of your system, e.g. DISTTYPE_DEB. You are -free to read this attribute, but you should use pool_setdisttype() -if you want to change it. +The distribution type of your system, e.g. DISTTYPE_DEB. You are free to +read this attribute, but you should use pool_setdisttype() if you want to +change it. *Id *whatprovidesdata*:: Multi-purpose Id storage holding zero terminated arrays of Ids. pool_whatprovides() returns an offset into this data. *Map *considered*:: -Optional bitmap that can make the library ignore solvables. If a -bitmap is set, only solvables that have a set bit in the bitmap -at their Id are considered usable. +Optional bitmap that can make the library ignore solvables. If a bitmap is +set, only solvables that have a set bit in the bitmap at their Id are +considered usable. *int debugmask*:: A mask that defines which debug events should be reported. pool_setdebuglevel() sets this mask. *Datapos pos*:: -An object storing some position in the repository data. Functions -like dataiterator_set_pos() set this object, accessing data with -a pseudo solvable Id of SOLVID_POS uses it. +An object storing some position in the repository data. Functions like +dataiterator_set_pos() set this object, accessing data with a pseudo +solvable Id of SOLVID_POS uses it. *Queue pooljobs*:: -A queue where fixed solver jobs can be stored. This jobs are -automatically added when solver_solve() is called, they are useful -to store configuration data like which packages should be multiversion -installed. +A queue where fixed solver jobs can be stored. This jobs are automatically +added when solver_solve() is called, they are useful to store configuration +data like which packages should be multiversion installed. Creation and Destruction ------------------------ @@ -96,8 +95,8 @@ Debugging and error reporting === Constants === *SOLV_FATAL*:: -Report the error and call ``exit(1)'' afterwards. You cannot mask -this level. Reports to stderr instead of stdout. +Report the error and call ``exit(1)'' afterwards. You cannot mask this +level. Reports to stderr instead of stdout. *SOLV_ERROR*:: Used to report errors. Reports to stderr instead of stdout. @@ -124,12 +123,12 @@ Used to report information about the solver dealing with conflicting rules. *SOLV_DEBUG_SOLUTIONS*:: -Used to report information about the solver creating solutions to -solve problems. +Used to report information about the solver creating solutions to solve +problems. *SOLV_DEBUG_POLICY*:: -Used to report information about the solver searching for an -optimal solution. +Used to report information about the solver searching for an optimal +solution. *SOLV_DEBUG_RESULT*:: Used by the debug functions to output results. @@ -157,8 +156,8 @@ setting a debug mask. void pool_setdebuglevel(Pool *pool, int level); -Set a predefined debug mask. A higher level generally means more -bits in the mask are set, thus more messages are printed. +Set a predefined debug mask. A higher level generally means more bits in +the mask are set, thus more messages are printed. void pool_setdebugmask(Pool *pool, int mask); @@ -173,14 +172,14 @@ bit, pool_debug() is also called with the message and type *SOLV_ERROR*. extern char *pool_errstr(Pool *pool); -Return the current error string stored in the pool. Like with -the libc's errno value, the string is only meaningful after a -function returned an error. +Return the current error string stored in the pool. Like with the libc's +errno value, the string is only meaningful after a function returned an +error. void pool_setdebugcallback(Pool *pool, void (*debugcallback)(Pool *, void *data, int type, const char *str), void *debugcallbackdata); -Set a custom debug callback function. Instead of writing to stdout -or stderr, the callback function will be called. +Set a custom debug callback function. Instead of writing to stdout or +stderr, the callback function will be called. Pool configuration @@ -189,77 +188,77 @@ Pool configuration === Constants === *DISTTYPE_RPM*:: - Used for systems with use rpm as low level package manager. +Used for systems with use rpm as low level package manager. *DISTTYPE_DEB*:: - Used for systems with use dpkg as low level package manager. +Used for systems with use dpkg as low level package manager. *DISTTYPE_ARCH*:: - Used for systems with use the arch linux package manager. +Used for systems with use the arch linux package manager. *DISTTYPE_HAIKU*:: - Used for systems with use haiku packages. +Used for systems with use haiku packages. *POOL_FLAG_PROMOTEEPOCH*:: - Promote the epoch of the providing dependency to the requesting - dependency if it does not contain an epoch. Used at some time - in old rpm versions, modern systems should never need this. +Promote the epoch of the providing dependency to the requesting +dependency if it does not contain an epoch. Used at some time +in old rpm versions, modern systems should never need this. *POOL_FLAG_FORBIDSELFCONFLICTS*:: - Disallow the installation of packages that conflict with themselves. - Debian always allows self-conflicting packages, rpm used to forbid - them but switched to also allowing them recently. +Disallow the installation of packages that conflict with themselves. +Debian always allows self-conflicting packages, rpm used to forbid +them but switched to also allowing them recently. *POOL_FLAG_OBSOLETEUSESPROVIDES*:: - Make obsolete type dependency match against provides instead of - just the name and version of packages. Very old versions of rpm - used the name/version, then it got switched to provides and later - switched back again to just name/version. +Make obsolete type dependency match against provides instead of +just the name and version of packages. Very old versions of rpm +used the name/version, then it got switched to provides and later +switched back again to just name/version. *POOL_FLAG_IMPLICITOBSOLETEUSESPROVIDES*:: - An implicit obsoletes is the internal mechanism to remove the - old package on an update. The default is to remove all packages - with the same name, rpm-5 switched to also removing packages - providing the same name. +An implicit obsoletes is the internal mechanism to remove the +old package on an update. The default is to remove all packages +with the same name, rpm-5 switched to also removing packages +providing the same name. *POOL_FLAG_OBSOLETEUSESCOLORS*:: - Rpm's multilib implementation (used in RedHat and Fedora) - distinguishes between 32bit and 64bit packages (the terminology - is that they have a different color). If obsoleteusescolors is - set, packages with different colors will not obsolete each other. +Rpm's multilib implementation (used in RedHat and Fedora) +distinguishes between 32bit and 64bit packages (the terminology +is that they have a different color). If obsoleteusescolors is +set, packages with different colors will not obsolete each other. *POOL_FLAG_IMPLICITOBSOLETEUSESCOLORS*:: - Same as POOL_FLAG_OBSOLETEUSESCOLORS, but used to find out if - packages of the same name can be installed in parallel. For - current Fedora systems, POOL_FLAG_OBSOLETEUSESCOLORS should be - false and POOL_FLAG_IMPLICITOBSOLETEUSESCOLORS should be true - (this is the default if FEDORA is defined when libsolv is - compiled). +Same as POOL_FLAG_OBSOLETEUSESCOLORS, but used to find out if +packages of the same name can be installed in parallel. For +current Fedora systems, POOL_FLAG_OBSOLETEUSESCOLORS should be +false and POOL_FLAG_IMPLICITOBSOLETEUSESCOLORS should be true +(this is the default if FEDORA is defined when libsolv is +compiled). *POOL_FLAG_NOINSTALLEDOBSOLETES*:: - New versions of rpm consider the obsoletes of installed packages - when checking for dependency, thus you may not install a package - that is obsoleted by some other installed package, unless you - also erase the other package. +New versions of rpm consider the obsoletes of installed packages +when checking for dependency, thus you may not install a package +that is obsoleted by some other installed package, unless you +also erase the other package. *POOL_FLAG_HAVEDISTEPOCH*:: - Mandriva added a new field called distepoch that gets checked in - version comparison if the epoch/version/release of two packages - are the same. +Mandriva added a new field called distepoch that gets checked in +version comparison if the epoch/version/release of two packages +are the same. *POOL_FLAG_NOOBSOLETESMULTIVERSION*:: - If a package is installed in multiversionmode, rpm used to ignore - both the implicit obsoletes and the obsolete dependency of a - package. This was changed to ignoring just the implicit obsoletes, - thus you may install multiple versions of the same name, but - obsoleted packages still get removed. +If a package is installed in multiversionmode, rpm used to ignore +both the implicit obsoletes and the obsolete dependency of a +package. This was changed to ignoring just the implicit obsoletes, +thus you may install multiple versions of the same name, but +obsoleted packages still get removed. *POOL_FLAG_ADDFILEPROVIDESFILTERED*:: - Make the addfileprovides method only add files from the standard - locations (i.e. the ``bin'' and ``etc'' directories). This is - useful if you have only few packages that use non-standard file - dependencies, but you still wand the fast speed that addfileprovides() - generates. +Make the addfileprovides method only add files from the standard +locations (i.e. the ``bin'' and ``etc'' directories). This is +useful if you have only few packages that use non-standard file +dependencies, but you still wand the fast speed that addfileprovides() +generates. === Functions === @@ -277,14 +276,13 @@ Set a flag to a new value. Returns the old value of the flag. int pool_get_flag(Pool *pool, int flag); -Get the value of a pool flag. See the constants section about the -meaning of the flags. +Get the value of a pool flag. See the constants section about the meaning +of the flags. void pool_set_rootdir(Pool *pool, const char *rootdir); -Set a specific root directory. Some library functions support a -flag that tells the function to prepend the rootdir to file -and directory names. +Set a specific root directory. Some library functions support a flag that +tells the function to prepend the rootdir to file and directory names. const char *pool_get_rootdir(Pool *pool); @@ -292,14 +290,13 @@ Return the current value of the root directory. char *pool_prepend_rootdir(Pool *pool, const char *dir); -Prepend the root directory to the _dir_ argument string. The -returned string has been newly allocated and needs to be -freed after use. +Prepend the root directory to the _dir_ argument string. The returned +string has been newly allocated and needs to be freed after use. char *pool_prepend_rootdir_tmp(Pool *pool, const char *dir); -Same as pool_prepend_rootdir, but uses the pool's temporary space -for allocation. +Same as pool_prepend_rootdir, but uses the pool's temporary space for +allocation. void pool_set_installed(Pool *pool, Repo *repo); @@ -308,10 +305,10 @@ i.e. the one that holds information about the installed packages. void pool_set_languages(Pool *pool, const char **languages, int nlanguages); -Set the language of your system. The library provides lookup functions -that return localized strings, for example for package descriptions. -You can set an array of languages to provide a fallback mechanism if -one language is not available. +Set the language of your system. The library provides lookup functions that +return localized strings, for example for package descriptions. You can +set an array of languages to provide a fallback mechanism if one language +is not available. void pool_setarch(Pool *pool, const char *arch); @@ -349,14 +346,15 @@ internal vendor equivalence class mechanism does not match your needs. void pool_setloadcallback(Pool *pool, int (*cb)(Pool *, Repodata *, void *), void *loadcbdata); -Define a callback function that gets called when repository metadata needs to -be loaded on demand. See the section about on demand loading in the libsolv-repodata -manual. +Define a callback function that gets called when repository metadata needs +to be loaded on demand. See the section about on demand loading in the +libsolv-repodata manual. void pool_setnamespacecallback(Pool *pool, Id (*cb)(Pool *, void *, Id, Id), void *nscbdata); -Define a callback function to implement custom namespace support. See -the section about namespace dependencies. +Define a callback function to implement custom namespace support. See the +section about namespace dependencies. + Id pool management ------------------ @@ -372,48 +370,44 @@ Represents a ``<'' relation. Represents a ``='' relation. *REL_GT*:: -Represents a ``>'' relation. You can use combinations of REL_GT, -REL_EQ and REL_LT or-ed together to create any relation you -like. +Represents a ``>'' relation. You can use combinations of REL_GT, REL_EQ, +and REL_LT or-ed together to create any relation you like. *REL_AND*:: -A boolean AND operation, the ``name'' and ``evr'' parts of the -relation can be two sub-dependencies. Packages must match both -parts of the dependency. +A boolean AND operation, the ``name'' and ``evr'' parts of the relation can +be two sub-dependencies. Packages must match both parts of the dependency. *REL_OR*:: -A boolean OR operation, the ``name'' and ``evr'' parts of the -relation can be two sub-dependencies. Packages can match any -part of the dependency. +A boolean OR operation, the ``name'' and ``evr'' parts of the relation can +be two sub-dependencies. Packages can match any part of the dependency. *REL_WITH*:: -Like REL_AND, but packages mast match both dependencies -simultaneously. See the section about boolean dependencies -about more information. +Like REL_AND, but packages mast match both dependencies simultaneously. See +the section about boolean dependencies about more information. *REL_NAMESPACE*:: -A special namespace relation. See the section about namespace -dependencies for more information. +A special namespace relation. See the section about namespace dependencies +for more information. *REL_ARCH*:: -A architecture filter dependency. The ``name'' part of the -relation is a sub-dependency, the ``evr'' part is the Id -of an architecture that the matching packages must have (note -that this is an exact match ignoring architecture policies). +A architecture filter dependency. The ``name'' part of the relation is a +sub-dependency, the ``evr'' part is the Id of an architecture that the +matching packages must have (note that this is an exact match ignoring +architecture policies). *REL_FILECONFLICT*:: -An internal file conflict dependency used to represent file -conflicts. See the pool_add_fileconflicts_deps() function. +An internal file conflict dependency used to represent file conflicts. See +the pool_add_fileconflicts_deps() function. *REL_COND*:: -A conditional dependency, the ``name'' sub-dependency is only -considered if the ``evr'' sub-dependency is fulfilled. See the -section about boolean dependencies about more information. +A conditional dependency, the ``name'' sub-dependency is only considered if +the ``evr'' sub-dependency is fulfilled. See the section about boolean +dependencies about more information. *REL_COMPAT*:: -A compat dependency used in Haiku to represent version ranges. -The ``name'' part is the actual version, the ``evr'' part is the -backwards compatibility version. +A compat dependency used in Haiku to represent version ranges. The +``name'' part is the actual version, the ``evr'' part is the backwards +compatibility version. === Functions === Id pool_str2id(Pool *pool, const char *str, int create); @@ -449,13 +443,13 @@ Convert an Id back into a string. If the Id is a relational Id, the const char *pool_id2rel(const Pool *pool, Id id); -Return the relation string of a relational Id. Returns an empty string -if the passed Id is not a relation. +Return the relation string of a relational Id. Returns an empty string if +the passed Id is not a relation. const char *pool_id2evr(const Pool *pool, Id id); -Return the ``evr'' part of a relational Id as string. Returns an empty string -if the passed Id is not a relation. +Return the ``evr'' part of a relational Id as string. Returns an empty +string if the passed Id is not a relation. const char *pool_dep2str(Pool *pool, Id id); @@ -465,9 +459,9 @@ the string is allocated on the pool's temporary space. void pool_freeidhashes(Pool *pool); -Free the hashes used to unify strings and relations. You can use this function -to save memory if you know that you will no longer create new strings and -relations. +Free the hashes used to unify strings and relations. You can use this +function to save memory if you know that you will no longer create new +strings and relations. Solvable functions @@ -528,10 +522,10 @@ NULL means that the part should match everything. int pool_match_dep(Pool *pool, Id d1, Id d2); -Returns ``1'' if the dependency _d1_ (the provider) is matched by the dependency -_d2_, otherwise ``0'' is returned. For two dependencies to match, both the -``name'' parts must match and the version range described by the ``evr'' parts -must overlap. +Returns ``1'' if the dependency _d1_ (the provider) is matched by the +dependency _d2_, otherwise ``0'' is returned. For two dependencies to +match, both the ``name'' parts must match and the version range described +by the ``evr'' parts must overlap. int pool_match_nevr(Pool *pool, Solvable *s, Id d); @@ -570,20 +564,21 @@ returning the offset into the array. void pool_addfileprovides(Pool *pool); -Some package managers like rpm allow dependencies on files contained in other -packages. To allow libsolv to deal with those dependencies in an efficient way, -you need to call the addfileprovides method after creating and reading all -repositories. This method will scan all dependency for file names and than scan -all packages for matching files. If a filename has been matched, it will be -added to the provides list of the corresponding package. +Some package managers like rpm allow dependencies on files contained in +other packages. To allow libsolv to deal with those dependencies in an +efficient way, you need to call the addfileprovides method after creating +and reading all repositories. This method will scan all dependency for file +names and than scan all packages for matching files. If a filename has been +matched, it will be added to the provides list of the corresponding +package. void pool_addfileprovides_queue(Pool *pool, Queue *idq, Queue *idqinst); Same as pool_addfileprovides, but the added Ids are returned in two Queues, -_idq_ for all repositories except the one containing the ``installed'' packages, -_idqinst_ for the latter one. This information can be stored in the meta section -of the repositories to speed up the next time the repository is loaded and -addfileprovides is called +_idq_ for all repositories except the one containing the ``installed'' +packages, _idqinst_ for the latter one. This information can be stored in +the meta section of the repositories to speed up the next time the +repository is loaded and addfileprovides is called void pool_flush_namespaceproviders(Pool *pool, Id ns, Id evr); @@ -609,21 +604,21 @@ Utility functions ----------------- char *pool_alloctmpspace(Pool *pool, int len); -Allocate space on the pool's temporary space area. This space has a -limited lifetime, it will be automatically freed after a fixed amount -(currently 16) of other pool_alloctmpspace() calls are done. +Allocate space on the pool's temporary space area. This space has a limited +lifetime, it will be automatically freed after a fixed amount (currently +16) of other pool_alloctmpspace() calls are done. void pool_freetmpspace(Pool *pool, const char *space); -Give the space allocated with pool_alloctmpspace back to the system. -You do not have to use this function, as the space is automatically -reclaimed, but it can be useful to extend the lifetime of other -pointers to the pool's temporary space area. +Give the space allocated with pool_alloctmpspace back to the system. You +do not have to use this function, as the space is automatically reclaimed, +but it can be useful to extend the lifetime of other pointers to the pool's +temporary space area. const char *pool_bin2hex(Pool *pool, const unsigned char *buf, int len); -Convert some binary data to hexadecimal, returning a string allocated -in the pool's temporary space area. +Convert some binary data to hexadecimal, returning a string allocated in +the pool's temporary space area. char *pool_tmpjoin(Pool *pool, const char *str1, const char *str2, const char *str3); @@ -632,12 +627,12 @@ area. You can use NULL arguments if you just want to join less strings. char *pool_tmpappend(Pool *pool, const char *str1, const char *str2, const char *str3); -Like pool_tmpjoin(), but if the first argument is the last allocated -space in the pool's temporary space area, it will be replaced with the -result of the join and no new temporary space slot will be used. -Thus you can join more then three strings by a combination of one -pool_tmpjoin() and multiple pool_tmpappend() calls. Note that the _str1_ -pointer is no longer usable after the call. +Like pool_tmpjoin(), but if the first argument is the last allocated space +in the pool's temporary space area, it will be replaced with the result of +the join and no new temporary space slot will be used. Thus you can join +more then three strings by a combination of one pool_tmpjoin() and multiple +pool_tmpappend() calls. Note that the _str1_ pointer is no longer usable +after the call. Data lookup @@ -645,8 +640,8 @@ Data lookup === Constants === *SOLVID_POS*:: -Use the data position stored in the pool for the lookup instead of -looking up the data of a solvable. +Use the data position stored in the pool for the lookup instead of looking +up the data of a solvable. *SOLVID_META*:: Use the data stored in the meta section of a repository (or repodata @@ -657,14 +652,14 @@ repodata's lookup functions instead. It's just listed for completeness. === Functions === const char *pool_lookup_str(Pool *pool, Id solvid, Id keyname); -Return the string value stored under the attribute _keyname_ -in solvable _solvid_. +Return the string value stored under the attribute _keyname_ in solvable +_solvid_. unsigned long long pool_lookup_num(Pool *pool, Id solvid, Id keyname, unsigned long long notfound); -Return the 64bit unsigned number stored under the attribute _keyname_ -in solvable _solvid_. If no such number is found, the value of the -_notfound_ argument is returned instead. +Return the 64bit unsigned number stored under the attribute _keyname_ in +solvable _solvid_. If no such number is found, the value of the _notfound_ +argument is returned instead. Id pool_lookup_id(Pool *pool, Id solvid, Id keyname); @@ -672,33 +667,36 @@ Return the Id stored under the attribute _keyname_ in solvable _solvid_. int pool_lookup_idarray(Pool *pool, Id solvid, Id keyname, Queue *q); -Fill the queue _q_ with the content of the Id array stored under the attribute -_keyname_ in solvable _solvid_. Returns ``1'' if an array was found, otherwise -the queue will be empty and ``0'' will be returned. +Fill the queue _q_ with the content of the Id array stored under the +attribute _keyname_ in solvable _solvid_. Returns ``1'' if an array was +found, otherwise the queue will be empty and ``0'' will be returned. int pool_lookup_void(Pool *pool, Id solvid, Id keyname); -Returns ``1'' if a void value is stored under the attribute _keyname_ in solvable -_solvid_, otherwise ``0''. +Returns ``1'' if a void value is stored under the attribute _keyname_ in +solvable _solvid_, otherwise ``0''. const char *pool_lookup_checksum(Pool *pool, Id solvid, Id keyname, Id *typep); -Return the checksum that is stored under the attribute _keyname_ in solvable _solvid_. -The type of the checksum will be returned over the _typep_ pointer. If no such -checksum is found, NULL will be returned and the type will be set to zero. Note that -the result is stored in the Pool's temporary space area. +Return the checksum that is stored under the attribute _keyname_ in +solvable _solvid_. The type of the checksum will be returned over the +_typep_ pointer. If no such checksum is found, NULL will be returned and +the type will be set to zero. Note that the result is stored in the Pool's +temporary space area. const unsigned char *pool_lookup_bin_checksum(Pool *pool, Id solvid, Id keyname, Id *typep); -Return the checksum that is stored under the attribute _keyname_ in solvable _solvid_. -Returns the checksum as binary data, you can use the returned type to calculate -the length of the checksum. No temporary space area is needed. +Return the checksum that is stored under the attribute _keyname_ in +solvable _solvid_. Returns the checksum as binary data, you can use the +returned type to calculate the length of the checksum. No temporary space +area is needed. const char *pool_lookup_deltalocation(Pool *pool, Id solvid, unsigned int *medianrp); -This is a utility lookup function to return the delta location for a delta rpm. -As solvables cannot store deltas, you have to use SOLVID_POS as argument and -set the Pool's datapos pointer to point to valid delta rpm data. +This is a utility lookup function to return the delta location for a delta +rpm. As solvables cannot store deltas, you have to use SOLVID_POS as +argument and set the Pool's datapos pointer to point to valid delta rpm +data. 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); @@ -739,8 +737,8 @@ like ``zypper''). const char *pool_selection2str(Pool *pool, Queue *selection, Id flagmask); -Convert a selection into a string. Useful for debugging purposes. -See the pool_job2str() function for the _flagmask_ argument. +Convert a selection into a string. Useful for debugging purposes. See the +pool_job2str() function for the _flagmask_ argument. Odds and Ends @@ -781,17 +779,99 @@ packages can only be replaced by other x86_64 packages, i686 packages can be replaced by i686 and i586 packages (but i686 packages will be preferred) and athlon is another name for the i686 architecture. +You can turn off the architecture replacement checks with the Solver's +SOLVER_FLAG_ALLOW_ARCHCHANGE flag. + Vendor Policies --------------- -bla bla +Different vendors often compile packages with different features, so +Libsolv only replace installed packages of one vendor with packages coming +from the same vendor. Also, while the version of a package is normally +defined by the upstream project, the release part of the version is +set by the vendor's package maintainer, so it's not meaningful to +do version comparisons for packages coming from different vendors. + +Vendor in this case means the SOLVABLE_VENDOR string stored in each +solvable. Sometimes a vendor changes names, or multiple vendors form a +group that coordinate their package building, so libsolv offers a way +to define that a group of vendors are compatible. You do that be +defining vendor equivalence classes, packages from a vendor from +one class may be replaced with packages from all the other vendors +in the class. + +There can be multiple equivalence classes, the set of allowed vendor +changes for an installed package is calculated by building the union +of all of the equivalence classes the vendor of the installed package +is part of. + +You can turn off the architecture replacement checks with the Solver's +SOLVER_FLAG_ALLOW_VENDORCHANGE flag. + Boolean Dependencies -------------------- -bla bla +Boolean Dependencies allow to build complex expressions from simple +dependencies. While rpm does not support boolean expressions in +dependencies and debian only allows an "OR" expression, libsolv +allows to arbitrary complex expressions. The following basic types +are supported: + +*REL_OR*:: +The expression is true if either the first dependency or the second +one is true. This is useful for package dependencies like ``Requires'', +where you can specify that either one of the packages need to be +installed. + +*REL_AND*:: +The expression is true if both dependencies are true. The packages +fulfilling the dependencies may be different, i.e. +``Supplements: perl AND python'' is true if both a package providing +perl and a package providing python are installed. The solver currently +only supports REL_AND in Supplements/Enhances dependencies, in other +types of dependencies it gets treated as REL_WITH. + +*REL_WITH*:: +The expression is true if both dependencies are true and are fulfilled by +the same package. Thus ``Supplements: perl AND python'' would only be true +if a package is installed that provides both dependencies (some kind +of multi-language interpreter). + +*REL_COND*:: +The expression is true if the first dependency is true or the second +dependency is false. Libsolv currently does not support this type of +dependency in the solver code. + +Each sub-dependency of a boolean dependency can in turn be a boolean +dependency, so you can chain them to create complex dependencies. + Namespace Dependencies ---------------------- -bla bla +Namespace dependencies can be used to implement dependencies on +attributes external to libsolv. An example would be a dependency +on the language set by the user. This types of dependencies are +usually only used for ``Conflicts'' or ``Supplements'' dependencies, +as the underlying package manager does not know how to deal with +them. + +If the library needs to evaluate a namespace dependency, it calls +the namespace callback function set in the pool. The callback +function can return a set of packages that ``provide'' the +dependency. If the dependency is provided by the system, the +returned set should consist of just the system solvable (Solvable +Id 1). + +The returned set of packages must be returned as offset into +the whatprovidesdata array. You can use the pool_queuetowhatprovides +function to convert a queue into such an offset. To ease programming +the callback function, the return values ``0'' and ``1'' are not +interpreted as an offset. ``0'' means that no package is in the +return set, ``1'' means that just the system solvable is in the set. + +The returned set is cached, so that for each namespace dependency +the callback is just called once. If you need to flush the cache (maybe +because the user has selected a different language), use the +pool_flush_namespaceproviders() function. Author |