func (self *BuildState) parentChanged(
parent dag.Node, pstate dag.NodeState, oldsig []byte) (
bool, error) {
var cursig []byte
var err error
if !(pstate == dag.SOURCE || pstate == dag.BUILT || self.checkAll()) {
// parent is an intermediate target that has not been built in
// the current run. We don't want the expense of calling
// Signature() for target nodes, because people don't normally
// modify targets behind their build tool's back. But it might
// have been modified by a previous build, in which case we'll
// use the signature previously recorded for parent *as a
// target*. This can still be fooled by modifying intermediate
// targets behind Fubsy's back, but that's what --check-all is
// for.
precord, err := self.db.LookupNode(parent.Name())
if err != nil {
return false, err
}
if precord != nil {
cursig = precord.TargetSignature()
}
}
if cursig == nil {
cursig, err = parent.Signature()
if err != nil {
// This should not happen: parent should exist and be readable,
// since we've already visited it earlier in the build and we
// avoid looking at failed/tainted parents.
return false, err
}
}
changed := parent.Changed(cursig, oldsig)
//log.Verbose("parent %s: oldsig=%v, cursig=%v, changed=%v",
// parent, oldsig, cursig, changed)
return changed, nil
}
