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authorTimo Teräs <timo.teras@iki.fi>2012-02-16 20:37:03 +0200
committerTimo Teräs <timo.teras@iki.fi>2012-02-16 21:11:22 +0200
commitb0c0b900db7b607d2976d98da6ee80b4b0b4698a (patch)
tree3c27508c24b32a9f123ad9dc6f4c4c65aaa5718e /src
parent53f8a36c1f621b5d53cb921bbda6ff0b2ecc756a (diff)
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solver: rework internals a bit
* cleaned up little bit on the internal state machine * the decision applying mechanism now aborts early to avoid work if we are approaching bad solution candidate * package availability checking is now done on-demand; which could still be improved
Diffstat (limited to 'src')
-rw-r--r--src/solver.c328
1 files changed, 190 insertions, 138 deletions
diff --git a/src/solver.c b/src/solver.c
index a12de28..e3b1597 100644
--- a/src/solver.c
+++ b/src/solver.c
@@ -38,8 +38,11 @@ struct apk_package_state {
struct apk_package *backtrack;
unsigned int topology_soft;
struct apk_score saved_score;
- unsigned short flags;
unsigned short conflicts;
+ unsigned availability_checked : 1;
+ unsigned unavailable : 1;
+ unsigned install_applied : 1;
+ unsigned flags : 4;
};
struct apk_name_state {
@@ -57,8 +60,8 @@ struct apk_name_state {
unsigned int solver_flags_local_mask : 4;
unsigned int solver_flags_inherited : 4;
- unsigned int availability_checked : 1;
unsigned int locked : 1;
+ unsigned int no_choices_left : 1;
unsigned int in_changeset : 1;
};
@@ -74,16 +77,22 @@ struct apk_solver_state {
struct apk_score minimum_penalty;
unsigned int solver_flags : 4;
- unsigned int refresh_name_states : 1;
struct apk_solution_array *best_solution;
struct apk_score best_score;
};
+typedef enum {
+ SOLVERR_SOLUTION = 0,
+ SOLVERR_PRUNED,
+ SOLVERR_EXPAND,
+ SOLVERR_STOP,
+} solver_result_t;
+
static void apply_constraint(struct apk_solver_state *ss, struct apk_dependency *dep);
static void undo_constraint(struct apk_solver_state *ss, struct apk_dependency *dep);
-static void push_decision(struct apk_solver_state *ss, struct apk_package *pkg,
- int flags);
+static solver_result_t push_decision(struct apk_solver_state *ss, struct apk_package *pkg,
+ int flags);
static void addscore(struct apk_score *a, struct apk_score *b)
{
@@ -258,32 +267,6 @@ static void sort_name(struct apk_solver_state *ss, struct apk_name *name)
sort_soft_dependencies(ss, name->pkgs->item[i]);
}
-static void prepare_name(struct apk_solver_state *ss, struct apk_name *name,
- struct apk_name_state *ns)
-{
- int i;
-
- if (ns->availability_checked)
- return;
-
- for (i = 0; i < name->pkgs->num; i++) {
- struct apk_package *pkg = name->pkgs->item[i];
- struct apk_package_state *ps = pkg_to_ps(pkg);
- struct apk_name_state *ns = name_to_ns(pkg->name);
-
- /* if package is needed for (re-)install */
- if ((pkg->ipkg == NULL) ||
- ((ns->solver_flags_local | ns->solver_flags_inherited |
- ss->solver_flags) & APK_SOLVERF_REINSTALL)) {
- /* and it's not available, we can't use it */
- if (!pkg_available(ss->db, pkg))
- ps->conflicts = 1024;
- }
- }
-
- ns->availability_checked = 1;
-}
-
static void foreach_locked_reverse_dependency(
struct apk_name *name,
void (*cb)(struct apk_package *rdepend, void *ctx), void *ctx)
@@ -428,7 +411,7 @@ static int get_preference(struct apk_solver_state *ss,
continue;
if (installable_only &&
- (ss->topology_position <= pkg0->topology_hard ||
+ (ss->topology_position < pkg0->topology_hard ||
(ps0->flags & APK_PKGSTF_DECIDED)))
continue;
@@ -459,6 +442,30 @@ static int install_if_missing(struct apk_solver_state *ss, struct apk_package *p
return missing;
}
+static int check_if_package_unavailable(struct apk_solver_state *ss, struct apk_package *pkg)
+{
+ struct apk_name *name = pkg->name;
+ struct apk_package_state *ps = pkg_to_ps(pkg);
+ struct apk_name_state *ns = name_to_ns(name);
+
+ /* installed and no-reinstall required? no check needed. */
+ if ((pkg->ipkg != NULL) &&
+ ((ns->solver_flags_local | ns->solver_flags_inherited |
+ ss->solver_flags) & APK_SOLVERF_REINSTALL) == 0)
+ return 0;
+
+ /* done already? */
+ if (ps->availability_checked)
+ return ps->unavailable;
+
+ /* and it's not available, we can't use it */
+ if (!pkg_available(ss->db, pkg))
+ ps->unavailable = 1;
+
+ ps->availability_checked = 1;
+ return ps->unavailable;
+}
+
static int update_name_state(struct apk_solver_state *ss, struct apk_name *name)
{
struct apk_name_state *ns = name_to_ns(name);
@@ -472,6 +479,9 @@ static int update_name_state(struct apk_solver_state *ss, struct apk_name *name)
unsigned int preferred_repos, allowed_repos;
int i, options = 0, skipped_options = 0;
+ if (ns->locked)
+ return ns->chosen != NULL;
+
preferred_pinning = ns->preferred_pinning ?: APK_DEFAULT_PINNING_MASK;
preferred_repos = get_pinning_mask_repos(ss->db, preferred_pinning);
allowed_pinning = ns->allowed_pinning | preferred_pinning;
@@ -488,15 +498,10 @@ static int update_name_state(struct apk_solver_state *ss, struct apk_name *name)
struct apk_package_state *ps0 = pkg_to_ps(pkg0);
if (ps0 == NULL ||
- pkg0->topology_hard >= ss->topology_position ||
- (ps0->flags & APK_PKGSTF_DECIDED))
- continue;
-
- if ((pkg0->repos != 0) && (pkg0->ipkg == NULL) && (pkg0->filename == NULL) &&
- !(pkg0->repos & allowed_repos)) {
- skipped_options++;
+ ss->topology_position < pkg0->topology_hard ||
+ (ps0->flags & APK_PKGSTF_DECIDED) ||
+ check_if_package_unavailable(ss, pkg0))
continue;
- }
if ((preferred_pkg == NULL) ||
(ps0->conflicts < preferred_ps->conflicts) ||
@@ -509,6 +514,16 @@ static int update_name_state(struct apk_solver_state *ss, struct apk_name *name)
preferred_ps = ps0;
}
+ /* pinning has not enabled the package */
+ if ((pkg0->repos != 0) && (pkg0->ipkg == NULL) &&
+ (pkg0->filename == NULL) && !(pkg0->repos & allowed_repos)) {
+ skipped_options++;
+ continue;
+ }
+
+ /* not directly required, there's at least one
+ * valid install_if, but for not this specific pkg;
+ * this might get enabled later */
if (ns->requirers == 0 && ns->install_ifs != 0 &&
install_if_missing(ss, pkg0)) {
skipped_options++;
@@ -523,17 +538,6 @@ static int update_name_state(struct apk_solver_state *ss, struct apk_name *name)
best_pkg = pkg0, best_topology = pkg0->topology_hard;
}
- if (skipped_options == 0 && options == 0) {
- if (!ns->locked) {
- ss->score.unsatisfiable += ns->requirers;
- ss->score.preference += name->pkgs->num;
- }
- ns->locked = 1;
- ns->chosen = NULL;
- } else {
- ns->locked = 0;
- }
-
if (ns->requirers == 0 && ns->install_ifs == 0) {
if (list_hashed(&ns->unsolved_list)) {
list_del(&ns->unsolved_list);
@@ -545,32 +549,39 @@ static int update_name_state(struct apk_solver_state *ss, struct apk_name *name)
} else {
if (!list_hashed(&ns->unsolved_list))
list_add(&ns->unsolved_list, &ss->unsolved_list_head);
- if (!ns->locked) {
- ns->chosen = best_pkg;
- if (preferred_pkg != NULL &&
- preferred_ps->conflicts < ns->requirers) {
- ns->minimum_penalty = (struct apk_score) {
- .unsatisfiable = preferred_ps->conflicts,
- .preference = get_preference(ss, preferred_pkg, FALSE),
- };
- dbg_printf("%s: min.penalty for name {%d, %d} from pkg " PKG_VER_FMT "\n",
- name->name,
- ns->minimum_penalty.unsatisfiable,
- ns->minimum_penalty.preference,
- PKG_VER_PRINTF(preferred_pkg));
- } else {
- ns->minimum_penalty = (struct apk_score) {
- .unsatisfiable = ns->requirers,
- .preference = name->pkgs->num,
- };
- }
- addscore(&ss->minimum_penalty, &ns->minimum_penalty);
+
+ ns->chosen = best_pkg;
+ if (preferred_pkg != NULL &&
+ preferred_ps->conflicts < ns->requirers) {
+ ns->minimum_penalty = (struct apk_score) {
+ .unsatisfiable = preferred_ps->conflicts,
+ .preference = get_preference(ss, preferred_pkg, FALSE),
+ };
+ dbg_printf("%s: min.penalty for name {%d, %d} from pkg " PKG_VER_FMT "\n",
+ name->name,
+ ns->minimum_penalty.unsatisfiable,
+ ns->minimum_penalty.preference,
+ PKG_VER_PRINTF(preferred_pkg));
+ } else {
+ ns->minimum_penalty = (struct apk_score) {
+ .unsatisfiable = ns->requirers,
+ .preference = name->pkgs->num,
+ };
+ dbg_printf("%s: min.penalty for name {%d, %d} from no pkg\n",
+ name->name,
+ ns->minimum_penalty.unsatisfiable,
+ ns->minimum_penalty.preference);
}
- dbg_printf("%s: added to unsolved: %d requirers, %d install_ifs, %d options (next topology %d)\n",
- name->name, ns->requirers, ns->install_ifs, options,
+ addscore(&ss->minimum_penalty, &ns->minimum_penalty);
+
+ dbg_printf("%s: added to unsolved: %d requirers, %d install_ifs, %d options, %d skipped options (next topology %d)\n",
+ name->name, ns->requirers, ns->install_ifs,
+ options, skipped_options,
best_topology);
}
+ ns->no_choices_left = (options == 0 && skipped_options == 0);
+
return options + skipped_options;
}
@@ -600,22 +611,40 @@ static void untrigger_install_if(struct apk_solver_state *ss,
}
}
-static void apply_decision(struct apk_solver_state *ss,
- struct apk_package *pkg,
- struct apk_package_state *ps)
+static solver_result_t apply_decision(struct apk_solver_state *ss,
+ struct apk_package *pkg,
+ struct apk_package_state *ps)
{
- struct apk_name_state *ns = name_to_ns(pkg->name);
+ struct apk_name *name = pkg->name;
+ struct apk_name_state *ns = name_to_ns(name);
- dbg_printf("apply_decision: " PKG_VER_FMT " %s\n", PKG_VER_PRINTF(pkg),
+ dbg_printf("-->apply_decision: " PKG_VER_FMT " %s\n", PKG_VER_PRINTF(pkg),
(ps->flags & APK_PKGSTF_INSTALL) ? "INSTALL" : "NO_INSTALL");
if (ps->flags & APK_PKGSTF_INSTALL) {
+ unsigned short preference;
+
subscore(&ss->minimum_penalty, &ns->minimum_penalty);
ns->minimum_penalty = (struct apk_score) { 0, 0 };
- ss->assigned_names++;
+ preference = get_preference(ss, pkg, FALSE);
ss->score.unsatisfiable += ps->conflicts;
- ss->score.preference += get_preference(ss, pkg, FALSE);
+ ss->score.preference += preference;
+ if (cmpscore2(&ss->score, &ss->minimum_penalty, &ss->best_score) >= 0) {
+ dbg_printf("install causing {%d,%d}, penalty too big: {%d,%d}+{%d,%d}>={%d,%d}\n",
+ ps->conflicts, preference,
+ ss->score.unsatisfiable, ss->score.preference,
+ ss->minimum_penalty.unsatisfiable, ss->minimum_penalty.preference,
+ ss->best_score.unsatisfiable, ss->best_score.preference
+ );
+
+ ss->score.unsatisfiable -= ps->conflicts;
+ ss->score.preference -= preference;
+ return SOLVERR_PRUNED;
+ }
+
+ ps->install_applied = 1;
+ ss->assigned_names++;
ns->chosen = pkg;
ns->locked = 1;
@@ -627,8 +656,29 @@ static void apply_decision(struct apk_solver_state *ss,
foreach_dependency(ss, pkg->depends, apply_constraint);
foreach_rinstall_if_pkg(ss, pkg, trigger_install_if);
} else {
- update_name_state(ss, pkg->name);
+ if (ns->locked == 0 && update_name_state(ss, pkg->name) == 0) {
+ subscore(&ss->minimum_penalty, &ns->minimum_penalty);
+ ns->minimum_penalty = (struct apk_score) { 0, 0 };
+
+ dbg_printf("%s: out of candidates, locking to none\n",
+ pkg->name->name);
+
+ ss->score.unsatisfiable += ns->requirers;
+ ss->score.preference += name->pkgs->num;
+ ns->locked = 1;
+ }
}
+
+ if (cmpscore2(&ss->score, &ss->minimum_penalty, &ss->best_score) >= 0) {
+ dbg_printf("install/uninstall finished penalty too big: {%d,%d}+{%d,%d}>={%d,%d}\n",
+ ss->score.unsatisfiable, ss->score.preference,
+ ss->minimum_penalty.unsatisfiable, ss->minimum_penalty.preference,
+ ss->best_score.unsatisfiable, ss->best_score.preference
+ );
+ return SOLVERR_PRUNED;
+ }
+
+ return SOLVERR_EXPAND;
}
static void undo_decision(struct apk_solver_state *ss,
@@ -637,7 +687,7 @@ static void undo_decision(struct apk_solver_state *ss,
{
struct apk_name_state *ns = name_to_ns(pkg->name);
- dbg_printf("undo_decision: " PKG_VER_FMT " %s\n", PKG_VER_PRINTF(pkg),
+ dbg_printf("-->undo_decision: " PKG_VER_FMT " %s\n", PKG_VER_PRINTF(pkg),
(ps->flags & APK_PKGSTF_INSTALL) ? "INSTALL" : "NO_INSTALL");
if (ps->flags & APK_PKGSTF_INSTALLIF)
@@ -646,21 +696,28 @@ static void undo_decision(struct apk_solver_state *ss,
ss->topology_position = pkg->topology_hard;
if (ps->flags & APK_PKGSTF_INSTALL) {
- ss->assigned_names--;
-
- foreach_rinstall_if_pkg(ss, pkg, untrigger_install_if);
- foreach_dependency(ss, pkg->depends, undo_constraint);
+ if (ps->install_applied) {
+ ps->install_applied = 0;
+ ss->assigned_names--;
+ foreach_rinstall_if_pkg(ss, pkg, untrigger_install_if);
+ foreach_dependency(ss, pkg->depends, undo_constraint);
+ }
ns->locked = 0;
ns->chosen = NULL;
+ } else {
+ /* UNINSTALL decision removed - either name is unlocked
+ * or locked to none */
+ ns->locked = 0;
+ ns->chosen = NULL;
}
ss->score = ps->saved_score;
update_name_state(ss, pkg->name);
}
-static void push_decision(struct apk_solver_state *ss, struct apk_package *pkg,
- int flags)
+static solver_result_t push_decision(struct apk_solver_state *ss, struct apk_package *pkg,
+ int flags)
{
struct apk_package_state *ps = pkg_to_ps(pkg);
@@ -678,7 +735,7 @@ static void push_decision(struct apk_solver_state *ss, struct apk_package *pkg,
}
ss->latest_decision = pkg;
- dbg_printf("push_decision: adding new BRANCH at topology_position %d (score: unsatisfied %d, preference %d)\n",
+ dbg_printf("-->push_decision: adding new BRANCH at topology_position %d (score: unsatisfied %d, preference %d)\n",
ss->topology_position,
ss->score.unsatisfiable,
ss->score.preference);
@@ -687,7 +744,7 @@ static void push_decision(struct apk_solver_state *ss, struct apk_package *pkg,
dbg_printf("triggers due to " PKG_VER_FMT "\n",
PKG_VER_PRINTF(pkg));
- apply_decision(ss, pkg, ps);
+ return apply_decision(ss, pkg, ps);
}
static int next_branch(struct apk_solver_state *ss)
@@ -700,29 +757,27 @@ static int next_branch(struct apk_solver_state *ss)
ps = pkg_to_ps(pkg);
if (ps->flags & APK_PKGSTF_ALT_BRANCH) {
- dbg_printf("next_branch: undo decision at topology_position %d\n",
+ dbg_printf("-->next_branch: undo decision at topology_position %d\n",
ss->topology_position);
ps->flags &= ~(APK_PKGSTF_ALT_BRANCH | APK_PKGSTF_DECIDED);
undo_decision(ss, pkg, ps);
ss->latest_decision = ps->backtrack;
- ss->refresh_name_states = 1;
} else {
- undo_decision(ss, pkg, ps);
-
- dbg_printf("next_branch: swapping BRANCH at topology_position %d\n",
+ dbg_printf("-->next_branch: swapping BRANCH at topology_position %d\n",
ss->topology_position);
+ undo_decision(ss, pkg, ps);
+
ps->flags |= APK_PKGSTF_ALT_BRANCH;
ps->flags ^= APK_PKGSTF_INSTALL;
- apply_decision(ss, pkg, ps);
- return 0;
+ return apply_decision(ss, pkg, ps);
}
}
- dbg_printf("next_branch: no more branches\n");
- return 1;
+ dbg_printf("-->next_branch: no more branches\n");
+ return SOLVERR_STOP;
}
static void inherit_name_state(struct apk_name *to, struct apk_name *from)
@@ -771,8 +826,6 @@ static void apply_constraint(struct apk_solver_state *ss, struct apk_dependency
struct apk_name_state *ns = name_to_ns(name);
int i;
- prepare_name(ss, name, ns);
-
if (ns->locked) {
if (ns->chosen)
dbg_printf("%s: locked to " PKG_VER_FMT " already\n",
@@ -808,8 +861,11 @@ static void apply_constraint(struct apk_solver_state *ss, struct apk_dependency
}
}
- if (ss->latest_decision != NULL)
+ if (ss->latest_decision != NULL) {
+ dbg_printf("%s: inheriting flags and pinning from %s\n",
+ name->name, ss->latest_decision->name->name);
inherit_name_state(name, ss->latest_decision->name);
+ }
if (!dep->optional)
ns->requirers++;
@@ -867,13 +923,12 @@ static int expand_branch(struct apk_solver_state *ss)
/* FIXME: change unsolved_list to a priority queue */
list_for_each_entry(ns, &ss->unsolved_list_head, unsolved_list) {
- if (ss->refresh_name_states)
+ if (ns->chosen == NULL && !ns->no_choices_left) {
+ /* we have not been able to determine candidate
+ * for the package, but is not yet completely
+ * excluded either. try updating it. */
update_name_state(ss, ns->name);
-
- /* ns->chosen can be NULL if the name has only install_if
- * requirers that got later conflicted, but it still has
- * other options that can get activated later due to more
- * complicated install_if rules in some other package. */
+ }
if (ns->chosen == NULL)
continue;
if (pkg_to_ps(ns->chosen)->topology_soft < ss->topology_position &&
@@ -882,20 +937,17 @@ static int expand_branch(struct apk_solver_state *ss)
else if (ns->chosen->topology_hard > topology0)
pkg0 = ns->chosen, topology0 = pkg0->topology_hard;
}
- ss->refresh_name_states = 0;
if (pkg0 == NULL) {
list_for_each_entry(ns, &ss->unsolved_list_head, unsolved_list) {
if (ns->locked)
continue;
-
ss->score.unsatisfiable += ns->requirers;
ss->score.preference += ns->name->pkgs->num;
}
dbg_printf("expand_branch: list is empty (%d unsatisfied)\n",
ss->score.unsatisfiable);
-
- return 1;
+ return SOLVERR_SOLUTION;
}
/* someone needs to provide this name -- find next eligible
@@ -907,9 +959,8 @@ static int expand_branch(struct apk_solver_state *ss)
flags = APK_PKGSTF_INSTALL;
else
flags = APK_PKGSTF_NOINSTALL;
- push_decision(ss, pkg0, flags);
- return 0;
+ return push_decision(ss, pkg0, flags);
}
static int get_tag(struct apk_database *db, unsigned short pinning_mask, unsigned int repos)
@@ -1113,7 +1164,8 @@ int apk_solver_solve(struct apk_database *db,
struct apk_solver_state *ss;
struct apk_installed_package *ipkg;
struct apk_score zero_score;
- int i, r;
+ solver_result_t r = SOLVERR_STOP;
+ int i;
ss = calloc(1, sizeof(struct apk_solver_state));
ss->db = db;
@@ -1135,29 +1187,29 @@ int apk_solver_solve(struct apk_database *db,
zero_score.preference);
do {
- if (cmpscore2(&ss->score, &ss->minimum_penalty, &ss->best_score) < 0) {
- r = expand_branch(ss);
- if (r) {
- dbg_printf("solution with: %d unsatisfiable, %d preference\n",
- ss->score.unsatisfiable,
- ss->score.preference);
-
- if (cmpscore(&ss->score, &ss->best_score) < 0)
- record_solution(ss);
-
- if (cmpscore(&zero_score, &ss->score) >= 0) {
- /* found solution - it is optimal because we permutate
- * each preferred local option first, and permutations
- * happen in topologally sorted order. */
- r = 0;
- break;
- }
- r = next_branch(ss);
+ /* need EXPAND if here, can return SOLUTION|PRUNED|EXPAND */
+ r = expand_branch(ss);
+ if (r == SOLVERR_SOLUTION) {
+ dbg_printf("solution with: %d unsatisfiable, %d preference\n",
+ ss->score.unsatisfiable,
+ ss->score.preference);
+
+ if (cmpscore(&ss->score, &ss->best_score) < 0)
+ record_solution(ss);
+
+ if (cmpscore(&zero_score, &ss->score) >= 0) {
+ /* found solution - it is optimal because we permutate
+ * each preferred local option first, and permutations
+ * happen in topologally sorted order. */
+ break;
}
- } else {
- r = next_branch(ss);
+ r = SOLVERR_PRUNED;
}
- } while (r == 0);
+ /* next_branch() returns PRUNED, STOP or EXPAND */
+ while (r == SOLVERR_PRUNED)
+ r = next_branch(ss);
+ /* STOP or EXPAND */
+ } while (r != SOLVERR_STOP);
/* collect packages */
if (changeset != NULL) {
@@ -1171,11 +1223,11 @@ int apk_solver_solve(struct apk_database *db,
} else {
apk_solution_array_free(&ss->best_solution);
}
- r = ss->best_score.unsatisfiable;
+ i = ss->best_score.unsatisfiable;
apk_solver_free(db);
free(ss);
- return r;
+ return i;
}
static void print_change(struct apk_database *db,