cmState: Move snapshot creation to the cmake instance.

Don't create a snapshot in Initialize(), but leave the creation
responsibility to the cmake instance instead.  Previously, the
cmState would Initialize() in its constructor, and the cmake instance
would re-Initialize() during Configure().  The end result was the
same and there would be one snapshot present.  However, cmLocalGenerator
also created a snapshot on construction, and that one was used, leaving
the first snapshot unused, and potential for off-by-one errors.

Fix that by making the cmLocalGenerator use the existing snapshot
if it is top-level.  Add a CurrentSnapshot to the cmake instance and
populated it while configuring a directory.  This will eventually
replace the 'current local generator' concept.  Fix the GetParent
implementation to be able to return the first snapshot.

1 files changed, 5 insertions, 0 deletions

diff --git a/Source/cmake.h b/Source/cmake.h
index c0a9b49..12b7e68 100644
--- a/Source/cmake.h
+++ b/Source/cmake.h
@@ -316,6 +316,10 @@ class cmake
   void WatchUnusedCli(const std::string& var);
 
   cmState* GetState() const { return this->State; }
+  void SetCurrentSnapshot(cmState::Snapshot snapshot)
+  { this->CurrentSnapshot = snapshot; }
+  cmState::Snapshot GetCurrentSnapshot() const
+  { return this->CurrentSnapshot; }
 
 protected:
   void RunCheckForUnusedVariables();
@@ -396,6 +400,7 @@ private:
   InstalledFilesMap InstalledFiles;
 
   cmState* State;
+  cmState::Snapshot CurrentSnapshot;
 
   void UpdateConversionPathTable();