Eliminate the "store" global variable

Also, move a few free-standing functions into StoreAPI and Derivation.

Also, introduce a non-nullable smart pointer, ref<T>, which is just a
wrapper around std::shared_ptr ensuring that the pointer is never
null. (For reference-counted values, this is better than passing a
"T&", because the latter doesn't maintain the refcount. Usually, the
caller will have a shared_ptr keeping the value alive, but that's not
always the case, e.g., when passing a reference to a std::thread via
std::bind.)

1 files changed, 2 insertions, 2 deletions

diff --git a/src/nix-store/dotgraph.cc b/src/nix-store/dotgraph.cc
index af4cd48e7757..326c668e06fb 100644
--- a/src/nix-store/dotgraph.cc
+++ b/src/nix-store/dotgraph.cc
@@ -94,7 +94,7 @@ void printClosure(const Path & nePath, const StoreExpr & fs)
 #endif
 
 
-void printDotGraph(const PathSet & roots)
+void printDotGraph(StoreAPI & store, const PathSet & roots)
 {
     PathSet workList(roots);
     PathSet doneSet;
@@ -111,7 +111,7 @@ void printDotGraph(const PathSet & roots)
         cout << makeNode(path, symbolicName(path), "#ff0000");
 
         PathSet references;
-        store->queryReferences(path, references);
+        store.queryReferences(path, references);
 
         for (PathSet::iterator i = references.begin();
              i != references.end(); ++i)