aboutsummaryrefslogtreecommitdiff
path: root/build2/algorithm.cxx
diff options
context:
space:
mode:
Diffstat (limited to 'build2/algorithm.cxx')
-rw-r--r--build2/algorithm.cxx48
1 files changed, 48 insertions, 0 deletions
diff --git a/build2/algorithm.cxx b/build2/algorithm.cxx
index a7126cc..cae6645 100644
--- a/build2/algorithm.cxx
+++ b/build2/algorithm.cxx
@@ -454,6 +454,54 @@ namespace build2
return e;
}
+ target*
+ execute_prerequisites (const target_type& tt,
+ action a, target& t, const timestamp& mt)
+ {
+ bool e (mt == timestamp_nonexistent);
+ target* r (nullptr);
+
+ for (target* pt: t.prerequisite_targets)
+ {
+ if (pt == nullptr) // Skip ignored.
+ continue;
+
+ target_state ts (execute (a, *pt));
+
+ if (!e)
+ {
+ // If this is an mtime-based target, then compare timestamps.
+ //
+ if (auto mpt = dynamic_cast<const mtime_target*> (pt))
+ {
+ timestamp mp (mpt->mtime ());
+
+ // What do we do if timestamps are equal? This can happen, for
+ // example, on filesystems that don't have subsecond resolution.
+ // There is not much we can do here except detect the case where
+ // the prerequisite was changed in this run which means the
+ // action must be executed on the target as well.
+ //
+ if (mt < mp || (mt == mp && ts == target_state::changed))
+ e = true;
+ }
+ else
+ {
+ // Otherwise we assume the prerequisite is newer if it was changed.
+ //
+ if (ts == target_state::changed)
+ e = true;
+ }
+ }
+
+ if (pt->is_a (tt))
+ r = pt;
+ }
+
+ assert (r != nullptr);
+ return e ? r : nullptr;
+ }
+
target_state
noop_action (action a, target& t)
{