libexpr: add findDerivationFilename

extract the derivation to filename:lineno heuristic

1 files changed, 2 insertions, 21 deletions

diff --git a/src/nix/edit.cc b/src/nix/edit.cc
index 3a27b9cca..a4aa40bed 100644
--- a/src/nix/edit.cc
+++ b/src/nix/edit.cc
@@ -36,28 +36,9 @@ struct CmdEdit : InstallableCommand
 
         auto v = installable->toValue(*state);
 
-        Value * v2;
-        try {
-            auto dummyArgs = state->allocBindings(0);
-            v2 = findAlongAttrPath(*state, "meta.position", *dummyArgs, *v);
-        } catch (Error &) {
-            throw Error("package '%s' has no source location information", installable->what());
-        }
-
-        auto pos = state->forceString(*v2);
-        debug("position is %s", pos);
-
-        auto colon = pos.rfind(':');
-        if (colon == std::string::npos)
-            throw Error("cannot parse meta.position attribute '%s'", pos);
-
-        std::string filename(pos, 0, colon);
+        std::string filename;
         int lineno;
-        try {
-            lineno = std::stoi(std::string(pos, colon + 1));
-        } catch (std::invalid_argument & e) {
-            throw Error("cannot parse line number '%s'", pos);
-        }
+        std::tie(filename, lineno) = findDerivationFilename(*state, *v, installable->what());
 
         stopProgressBar();