On Fri, Jan 16, 2009 at 8:13 PM, Bryan Ischo wrote:

This change reorganizes the internal code so that packages are resolved one at a time instead of all at once from a list. This will allow a future checkin to prompt the user to see if they'd rather remove unresolvable packages from the tranasaction and continue, or fail the transaction. This change does not affect the actual behavior of libalpm and all tests pass without changes.

Please wrap your commit message at 76 characters so it doesn't make the git-log console output go crazy.

Signed-off-by: Bryan Ischo --- lib/libalpm/deps.c | 64 +++++++++++++++++++++++++++++++++++++++++++--------- lib/libalpm/deps.h | 5 ++- lib/libalpm/sync.c | 52 +++++++++++++++++++++++++++++++++--------- 3 files changed, 97 insertions(+), 24 deletions(-)

diff --git a/lib/libalpm/deps.c b/lib/libalpm/deps.c index 940f12c..a5b57ad 100644 --- a/lib/libalpm/deps.c +++ b/lib/libalpm/deps.c @@ -546,17 +546,33 @@ pmpkg_t *_alpm_resolvedep(pmdepend_t *dep, alpm_list_t *dbs, alpm_list_t *exclud return(NULL); }

-/* populates list with packages that need to be installed to satisfy all - * dependencies of packages in list - * - * @param remove contains packages elected for removal +/* Computes resolvable dependencies for a given package and adds that package + * and those resolvable dependencies to a list. + * + * @param local is the local database + * @param dbs_sync are the sync databases + * @param pkg is the package to resolve + * @param packages is a pointer to a list of packages which will be + * searched first for any dependency packages needed to complete the + * resolve, and to which will be added any [pkg] and all of its + * dependencies not already on the list + * @param remove is the set of packages which will be removed in this + * transaction + * @param data returns the dependency which could not be satisfied in the + * event of an error + * @return 0 on success, with [pkg] and all of its dependencies not already on + * the [*packages] list added to that list, or -1 on failure due to an + * unresolvable dependency, in which case the [*packages] list will be + * unmodified by this function */ -int _alpm_resolvedeps(pmdb_t *local, alpm_list_t *dbs_sync, alpm_list_t *list, - alpm_list_t *remove, alpm_list_t **data) +int _alpm_resolvedeps(pmdb_t *local, alpm_list_t *dbs_sync, pmpkg_t *pkg, + alpm_list_t **packages, alpm_list_t *remove, + alpm_list_t **data)

No need to use two lines for what will fit on one line.

{ alpm_list_t *i, *j; alpm_list_t *targ; alpm_list_t *deps = NULL; + alpm_list_t *working;

ALPM_LOG_FUNC;

@@ -564,8 +580,21 @@ int _alpm_resolvedeps(pmdb_t *local, alpm_list_t *dbs_sync, alpm_list_t *list, return(-1); }

+ if(_alpm_pkg_find(*packages, pkg->name) != NULL) { + /* It's already on the list, meaning it's already been resolved and + it and all of its dependencies have already been added */ Drop this comment- its pretty obvious what the conditional is checking.

+ return(0); + } + + /* [pkg] has not already been resolved into the packages list, so put it + * on that list */ + *packages = alpm_list_add(*packages, pkg); + /* And keep track of the head of the newly-added elements, so that they + can be quickly cut from the list on error */ + working = alpm_list_last(*packages); + _alpm_log(PM_LOG_DEBUG, "started resolving dependencies\n"); - for(i = list; i; i = i->next) { + for(i = working; i; i = i->next) { pmpkg_t *tpkg = i->data; targ = alpm_list_add(NULL, tpkg); deps = alpm_checkdeps(_alpm_db_get_pkgcache(local), 0, remove, targ); @@ -573,12 +602,12 @@ int _alpm_resolvedeps(pmdb_t *local, alpm_list_t *dbs_sync, alpm_list_t *list, for(j = deps; j; j = j->next) { pmdepmissing_t *miss = j->data; pmdepend_t *missdep = alpm_miss_get_dep(miss); - /* check if one of the packages in list already satisfies this dependency */ - if(_alpm_find_dep_satisfier(list, missdep)) { + /* check if one of the packages in the [*packages] list already satisfies this dependency */ + if(_alpm_find_dep_satisfier(*packages, missdep)) { continue; } /* find a satisfier package in the given repositories */ - pmpkg_t *spkg = _alpm_resolvedep(missdep, dbs_sync, list, tpkg); + pmpkg_t *spkg = _alpm_resolvedep(missdep, dbs_sync, *packages, tpkg); if(!spkg) { pm_errno = PM_ERR_UNSATISFIED_DEPS; char *missdepstring = alpm_dep_compute_string(missdep); @@ -592,13 +621,26 @@ int _alpm_resolvedeps(pmdb_t *local, alpm_list_t *dbs_sync, alpm_list_t *list, *data = alpm_list_add(*data, missd); } } + /* Remove all packages that were added to [*packages], so that + * we return from error cleanly without having affected the + * [*packages] list. Detach the tail of the list beginning at + * [working] from the packages list and free it. */ + if (working == *packages) { + *packages = NULL; + } + else { + (*packages)->prev = working->prev; + (*packages)->prev->next = NULL; + working->prev = NULL; + } + alpm_list_free(working); Hmm, I'm not a fan of this manual manipulation- the data structures are there for a reason, so we aren't playing with pointers. The problem here is edge cases are likely to break- I'm not sure if you know, but we ensured alpm_list_last() is an O(1) operation for example by linking first->prev to the last item (the inverse is not true).

You might be better off keeping two independent lists and then finding a way to join them when we are past the point of no return.

alpm_list_free_inner(deps, (alpm_list_fn_free)_alpm_depmiss_free); alpm_list_free(deps); return(-1); } else { _alpm_log(PM_LOG_DEBUG, "pulling dependency %s (needed by %s)\n", alpm_pkg_get_name(spkg), alpm_pkg_get_name(tpkg)); - list = alpm_list_add(list, spkg); + *packages = alpm_list_add(*packages, spkg); } } alpm_list_free_inner(deps, (alpm_list_fn_free)_alpm_depmiss_free); diff --git a/lib/libalpm/deps.h b/lib/libalpm/deps.h index 2f3c450..9dca91d 100644 --- a/lib/libalpm/deps.h +++ b/lib/libalpm/deps.h @@ -48,8 +48,9 @@ void _alpm_depmiss_free(pmdepmissing_t *miss); alpm_list_t *_alpm_sortbydeps(alpm_list_t *targets, int reverse); void _alpm_recursedeps(pmdb_t *db, alpm_list_t *targs, int include_explicit); pmpkg_t *_alpm_resolvedep(pmdepend_t *dep, alpm_list_t *dbs, alpm_list_t *excluding, pmpkg_t *tpkg); -int _alpm_resolvedeps(pmdb_t *local, alpm_list_t *dbs_sync, alpm_list_t *list, - alpm_list_t *remove, alpm_list_t **data); +int _alpm_resolvedeps(pmdb_t *local, alpm_list_t *dbs_sync, pmpkg_t *pkg, + alpm_list_t **packages, alpm_list_t *remove, + alpm_list_t **data);

Coalesce the previous two lines. If you do that I'll stop pulling stupid words like 'coalesce' out of my vocab too. :)

int _alpm_dep_edge(pmpkg_t *pkg1, pmpkg_t *pkg2); pmdepend_t *_alpm_splitdep(const char *depstring); pmpkg_t *_alpm_find_dep_satisfier(alpm_list_t *pkgs, pmdepend_t *dep); diff --git a/lib/libalpm/sync.c b/lib/libalpm/sync.c index b458874..5daadbd 100644 --- a/lib/libalpm/sync.c +++ b/lib/libalpm/sync.c @@ -399,6 +399,7 @@ int _alpm_sync_prepare(pmtrans_t *trans, pmdb_t *db_local, alpm_list_t *dbs_sync { alpm_list_t *deps = NULL; alpm_list_t *list = NULL, *remove = NULL; /* allow checkdeps usage with trans->packages */ + alpm_list_t *unresolvable = NULL; alpm_list_t *i, *j; int ret = 0;

@@ -411,15 +412,14 @@ int _alpm_sync_prepare(pmtrans_t *trans, pmdb_t *db_local, alpm_list_t *dbs_sync *data = NULL; }

- for(i = trans->packages; i; i = i->next) { - pmsyncpkg_t *sync = i->data; - list = alpm_list_add(list, sync->pkg); - } - - if(!(trans->flags & PM_TRANS_FLAG_NODEPS)) { - /* store a pointer to the last original target so we can tell what was - * pulled by resolvedeps */ - alpm_list_t *pulled = alpm_list_last(list); + if(trans->flags & PM_TRANS_FLAG_NODEPS) { + /* Simply build up [list] from all of the transaction packages */ Unnecessary comment.

+ for(i = trans->packages; i; i = i->next) { + pmsyncpkg_t *sync = i->data; + list = alpm_list_add(list, sync->pkg); + } + } else { + /* Build up list by repeatedly resolving each transaction package */ /* Resolve targets dependencies */ EVENT(trans, PM_TRANS_EVT_RESOLVEDEPS_START, NULL, NULL); _alpm_log(PM_LOG_DEBUG, "resolving target's dependencies\n"); @@ -432,14 +432,43 @@ int _alpm_sync_prepare(pmtrans_t *trans, pmdb_t *db_local, alpm_list_t *dbs_sync } }

- if(_alpm_resolvedeps(db_local, dbs_sync, list, remove, data) == -1) { + /* Resolve packages in the transaction one at a time, in addtion + building up a list of packages which could not be resolved. */ + for(i = trans->packages; i; i = i->next) { + pmpkg_t *pkg = ((pmsyncpkg_t *) i->data)->pkg; + if(_alpm_resolvedeps(db_local, dbs_sync, pkg, &list, remove, data) == -1) { + /* Failed to resolve a dependency of [pkg]. It goes on the + unresolvable list. [list] was not touched, so no + unnecessary dependency packages were added to it. */ I know it sounds weird to hate on comments, but it takes me a lot longer to get through the comment than just reading the code and seeing what it says. Shorten or kill this one.

+ unresolvable = alpm_list_add(unresolvable, pkg); + } + /* Else, [list] now additionally contains [pkg] and all of its + dependencies not already on the list */ + } + + /* If there were unresolvable top-level packages, fail the + transaction. In a future checkin, the user will be asked if they'd + like to drop the unresolvable packages intead. */ Don't tie in future checkins, we all know its coming. Just drop the comment.

+ if(unresolvable != NULL) { /* pm_errno is set by resolvedeps */ ret = -1; goto cleanup; }

- for(i = pulled->next; i; i = i->next) { + /* Add all packages which were "pulled" (i.e. weren't already in the + transaction) to the transaction in pmsyncpkg_t structures */ + for(i = list; i; i = i->next) { pmpkg_t *spkg = i->data; + for(j = trans->packages; j; j = j->next) { + if(_alpm_pkg_cmp(spkg, ((pmsyncpkg_t *) j->data)->pkg) == 0) { + spkg = NULL; + break; + } + } + if (spkg == NULL) { + continue; + } + pmsyncpkg_t *sync = _alpm_sync_new(PM_PKG_REASON_DEPEND, spkg, NULL); if(sync == NULL) { ret = -1; @@ -627,6 +656,7 @@ int _alpm_sync_prepare(pmtrans_t *trans, pmdb_t *db_local, alpm_list_t *dbs_sync cleanup: alpm_list_free(list); alpm_list_free(remove); + alpm_list_free(unresolvable);

return(ret); }

I know I commented a lot, but overall this patch looks fine to me. If you make the adjustments I've pointed out I'll merge this. -Dan