StorePath: Rewrite in C++

On nix-env -qa -f '<nixpkgs>', this reduces maximum RSS by 20970 KiB
and runtime by 0.8%. This is mostly because we're not parsing the hash
part as a hash anymore (just validating that it consists of base-32
characters).

Also, replace storePathToHash() by StorePath::hashPart().

1 files changed, 5 insertions, 5 deletions

diff --git a/src/nix/why-depends.cc b/src/nix/why-depends.cc
index 6057beedb..a4ee2d971 100644
--- a/src/nix/why-depends.cc
+++ b/src/nix/why-depends.cc
@@ -76,7 +76,7 @@ struct CmdWhyDepends : SourceExprCommand
         auto packagePath = toStorePath(store, Build, package);
         auto dependency = parseInstallable(*this, store, _dependency, false);
         auto dependencyPath = toStorePath(store, NoBuild, dependency);
-        auto dependencyPathHash = storePathToHash(store->printStorePath(dependencyPath));
+        auto dependencyPathHash = dependencyPath.hashPart();
 
         StorePathSet closure;
         store->computeFSClosure({packagePath}, closure, false, false);
@@ -175,7 +175,7 @@ struct CmdWhyDepends : SourceExprCommand
                 auto & node2 = graph.at(ref);
                 if (node2.dist == inf) continue;
                 refs.emplace(node2.dist, &node2);
-                hashes.insert(storePathToHash(store->printStorePath(node2.path)));
+                hashes.insert(std::string(node2.path.hashPart()));
             }
 
             /* For each reference, find the files and symlinks that
@@ -211,7 +211,7 @@ struct CmdWhyDepends : SourceExprCommand
                                     p2,
                                     hilite(filterPrintable(
                                             std::string(contents, pos2, pos - pos2 + hash.size() + margin)),
-                                        pos - pos2, storePathHashLen,
+                                        pos - pos2, StorePath::HashLen,
                                         getColour(hash))));
                         }
                     }
@@ -224,7 +224,7 @@ struct CmdWhyDepends : SourceExprCommand
                         auto pos = target.find(hash);
                         if (pos != std::string::npos)
                             hits[hash].emplace_back(fmt("%s -> %s\n", p2,
-                                    hilite(target, pos, storePathHashLen, getColour(hash))));
+                                    hilite(target, pos, StorePath::HashLen, getColour(hash))));
                     }
                 }
             };
@@ -235,7 +235,7 @@ struct CmdWhyDepends : SourceExprCommand
 
             RunPager pager;
             for (auto & ref : refs) {
-                auto hash = storePathToHash(store->printStorePath(ref.second->path));
+                std::string hash(ref.second->path.hashPart());
 
                 bool last = all ? ref == *refs.rbegin() : true;