libexpr: add findDerivationFilename

extract the derivation to filename:lineno heuristic

2 files changed, 3 insertions, 43 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();
 
diff --git a/src/nix/repl.cc b/src/nix/repl.cc
index d4334cf7f..5cfb408f7 100644
--- a/src/nix/repl.cc
+++ b/src/nix/repl.cc
@@ -481,28 +481,7 @@ bool NixRepl::processLine(string line)
             lineno = 0;
         } else {
             // assume it's a derivation
-            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", arg);
-            }
-
-            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);
-
-            filename = std::string(pos, 0, colon);
-            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, arg);
         }
 
         // Open in EDITOR