Add Store::buildPathsWithResults()

This function is like buildPaths(), except that it returns a vector of
BuildResults containing the exact statuses and output paths of each
derivation / substitution. This is convenient for functions like
Installable::build(), because they then don't need to do another
series of calls to get the outputs of CA derivations. It's also a
precondition to impure derivations, where we *can't* query the output
of those derivations since they're not stored in the Nix database.

Note that PathSubstitutionGoal can now also return a BuildStatus.

1 files changed, 8 insertions, 0 deletions

diff --git a/src/libstore/remote-store.hh b/src/libstore/remote-store.hh
index 2628206b1..9f6f50593 100644
--- a/src/libstore/remote-store.hh
+++ b/src/libstore/remote-store.hh
@@ -97,6 +97,11 @@ public:
 
     void buildPaths(const std::vector<DerivedPath> & paths, BuildMode buildMode, std::shared_ptr<Store> evalStore) override;
 
+    std::vector<BuildResult> buildPathsWithResults(
+        const std::vector<DerivedPath> & paths,
+        BuildMode buildMode,
+        std::shared_ptr<Store> evalStore) override;
+
     BuildResult buildDerivation(const StorePath & drvPath, const BasicDerivation & drv,
         BuildMode buildMode) override;
 
@@ -171,6 +176,9 @@ private:
 
     std::atomic_bool failed{false};
 
+    void copyDrvsFromEvalStore(
+        const std::vector<DerivedPath> & paths,
+        std::shared_ptr<Store> evalStore);
 };