cmLocalGenerator: Require a valid cmState::Snapshot in the ctor.

Refactor the local generator creation API to accept a
cmState::Snapshot.  Adjust MakeLocalGenerator to use the 'current'
snapshot in cases where there is no parent.  Create the snapshot
for subdirectories in cmMakefile::AddSubdirectory.

This means that snapshots are now created at the point of extending the tree,
as appropriate, and independently of the cmLocalGenerator and cmMakefile they
represent the state for.

1 files changed, 4 insertions, 7 deletions

diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index d00b677daa..7d8596ea19 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -44,19 +44,16 @@
 #endif
 
 cmLocalGenerator::cmLocalGenerator(cmGlobalGenerator* gg,
-                                   cmLocalGenerator* parent)
+                                   cmLocalGenerator* parent,
+                                   cmState::Snapshot snapshot)
+  : StateSnapshot(snapshot)
 {
+  assert(snapshot.IsValid());
   this->GlobalGenerator = gg;
   this->Parent = parent;
   if (parent)
     {
     parent->AddChild(this);
-    this->StateSnapshot =
-        this->GetState()->CreateSnapshot(parent->StateSnapshot);
-    }
-  else
-    {
-    this->StateSnapshot = gg->GetCMakeInstance()->GetCurrentSnapshot();
     }
 
   this->Makefile = new cmMakefile(this);