Use `BuildableReq` for `buildPaths` and `ensurePath`

This avoids an ambiguity where the `StorePathWithOutputs { drvPath, {}
}` could mean "build `brvPath`" or "substitute `drvPath`" depending on
context.

It also brings the internals closer in line to the new CLI, by
generalizing the `Buildable` type is used there and makes that
distinction already.

In doing so, relegate `StorePathWithOutputs` to being a type just for
backwards compatibility (CLI and RPC).

1 files changed, 35 insertions, 0 deletions

diff --git a/src/libstore/path-with-outputs.cc b/src/libstore/path-with-outputs.cc
index a898ad09c..353286ac6 100644
--- a/src/libstore/path-with-outputs.cc
+++ b/src/libstore/path-with-outputs.cc
@@ -1,3 +1,4 @@
+#include "path-with-outputs.hh"
 #include "store-api.hh"
 
 namespace nix {
@@ -10,6 +11,40 @@ std::string StorePathWithOutputs::to_string(const Store & store) const
 }
 
 
+BuildableReq StorePathWithOutputs::toBuildableReq() const
+{
+    if (!outputs.empty() || path.isDerivation())
+        return BuildableReqFromDrv { path, outputs };
+    else
+        return BuildableOpaque { path };
+}
+
+
+std::vector<BuildableReq> toBuildableReqs(const std::vector<StorePathWithOutputs> ss)
+{
+	std::vector<BuildableReq> reqs;
+	for (auto & s : ss) reqs.push_back(s.toBuildableReq());
+	return reqs;
+}
+
+
+std::variant<StorePathWithOutputs, StorePath> StorePathWithOutputs::tryFromBuildableReq(const BuildableReq & p)
+{
+    return std::visit(overloaded {
+        [&](BuildableOpaque bo) -> std::variant<StorePathWithOutputs, StorePath> {
+            if (bo.path.isDerivation()) {
+                // drv path gets interpreted as "build", not "get drv file itself"
+                return bo.path;
+            }
+            return StorePathWithOutputs { bo.path };
+        },
+        [&](BuildableReqFromDrv bfd) -> std::variant<StorePathWithOutputs, StorePath> {
+            return StorePathWithOutputs { bfd.drvPath, bfd.outputs };
+        },
+    }, p);
+}
+
+
 std::pair<std::string_view, StringSet> parsePathWithOutputs(std::string_view s)
 {
     size_t n = s.find("!");