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.)

2 files changed, 8 insertions, 9 deletions

diff --git a/src/libmain/shared.cc b/src/libmain/shared.cc
index 5106739c81ce..656d04cab011 100644
--- a/src/libmain/shared.cc
+++ b/src/libmain/shared.cc
@@ -4,7 +4,6 @@
 #include "globals.hh"
 #include "store-api.hh"
 #include "util.hh"
-#include "misc.hh"
 
 #include <iostream>
 #include <cctype>
@@ -47,22 +46,22 @@ void printGCWarning()
 }
 
 
-void printMissing(StoreAPI & store, const PathSet & paths)
+void printMissing(ref<StoreAPI> store, const PathSet & paths)
 {
     unsigned long long downloadSize, narSize;
     PathSet willBuild, willSubstitute, unknown;
-    queryMissing(store, paths, willBuild, willSubstitute, unknown, downloadSize, narSize);
+    store->queryMissing(paths, willBuild, willSubstitute, unknown, downloadSize, narSize);
     printMissing(store, willBuild, willSubstitute, unknown, downloadSize, narSize);
 }
 
 
-void printMissing(StoreAPI & store, const PathSet & willBuild,
+void printMissing(ref<StoreAPI> store, const PathSet & willBuild,
     const PathSet & willSubstitute, const PathSet & unknown,
     unsigned long long downloadSize, unsigned long long narSize)
 {
     if (!willBuild.empty()) {
         printMsg(lvlInfo, format("these derivations will be built:"));
-        Paths sorted = topoSortPaths(store, willBuild);
+        Paths sorted = store->topoSortPaths(willBuild);
         reverse(sorted.begin(), sorted.end());
         for (auto & i : sorted)
             printMsg(lvlInfo, format("  %1%") % i);
diff --git a/src/libmain/shared.hh b/src/libmain/shared.hh
index 8e756bd5e842..6f826d8f6fd7 100644
--- a/src/libmain/shared.hh
+++ b/src/libmain/shared.hh
@@ -19,8 +19,6 @@ public:
     Exit(int status) : status(status) { }
 };
 
-class StoreAPI;
-
 int handleExceptions(const string & programName, std::function<void()> fun);
 
 void initNix();
@@ -33,9 +31,11 @@ void printVersion(const string & programName);
 /* Ugh.  No better place to put this. */
 void printGCWarning();
 
-void printMissing(StoreAPI & store, const PathSet & paths);
+class StoreAPI;
+
+void printMissing(ref<StoreAPI> store, const PathSet & paths);
 
-void printMissing(StoreAPI & store, const PathSet & willBuild,
+void printMissing(ref<StoreAPI> store, const PathSet & willBuild,
     const PathSet & willSubstitute, const PathSet & unknown,
     unsigned long long downloadSize, unsigned long long narSize);