From 7b312a8762988ff7a8e0f0890fcd2406cd89c1a3 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Tue, 16 Apr 2019 14:27:54 +0200
Subject: [PATCH] Pass stuff by reference

---
 src/libexpr/primops/flake.cc | 17 +++++++++--------
 src/libexpr/primops/flake.hh |  7 ++++---
 2 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/src/libexpr/primops/flake.cc b/src/libexpr/primops/flake.cc
index f65ae09ea..3d11d9ec4 100644
--- a/src/libexpr/primops/flake.cc
+++ b/src/libexpr/primops/flake.cc
@@ -34,7 +34,7 @@ std::shared_ptr<FlakeRegistry> readRegistry(const Path & path)
 }
 
 /* Write a registry to a file. */
-void writeRegistry(const FlakeRegistry & registry, Path path)
+void writeRegistry(const FlakeRegistry & registry, const Path & path)
 {
     nlohmann::json json;
     json["version"] = 1;
@@ -99,7 +99,7 @@ LockFile readLockFile(const Path & path)
     return lockFile;
 }
 
-nlohmann::json flakeEntryToJson(LockFile::FlakeEntry & entry)
+nlohmann::json flakeEntryToJson(const LockFile::FlakeEntry & entry)
 {
     nlohmann::json json;
     json["uri"] = entry.ref.to_string();
@@ -110,7 +110,7 @@ nlohmann::json flakeEntryToJson(LockFile::FlakeEntry & entry)
     return json;
 }
 
-void writeLockFile(LockFile lockFile, Path path)
+void writeLockFile(const LockFile & lockFile, const Path & path)
 {
     nlohmann::json json;
     json["version"] = 1;
@@ -156,7 +156,8 @@ const std::vector<std::shared_ptr<FlakeRegistry>> EvalState::getFlakeRegistries(
 }
 
 static FlakeRef lookupFlake(EvalState & state, const FlakeRef & flakeRef,
-    std::vector<std::shared_ptr<FlakeRegistry>> registries, std::vector<FlakeRef> pastSearches = {})
+    const std::vector<std::shared_ptr<FlakeRegistry>> & registries,
+    std::vector<FlakeRef> pastSearches = {})
 {
     for (std::shared_ptr<FlakeRegistry> registry : registries) {
         auto i = registry->entries.find(flakeRef);
@@ -362,14 +363,14 @@ Dependencies resolveFlake(EvalState & state, const FlakeRef & topRef, bool impur
     return deps;
 }
 
-LockFile::FlakeEntry dependenciesToFlakeEntry(Dependencies & deps)
+LockFile::FlakeEntry dependenciesToFlakeEntry(const Dependencies & deps)
 {
     LockFile::FlakeEntry entry(deps.flake.ref);
 
-    for (Dependencies & deps : deps.flakeDeps)
+    for (auto & deps : deps.flakeDeps)
         entry.flakeEntries.insert_or_assign(deps.flake.id, dependenciesToFlakeEntry(deps));
 
-    for (NonFlake & nonFlake : deps.nonFlakeDeps)
+    for (auto & nonFlake : deps.nonFlakeDeps)
         entry.nonFlakeEntries.insert_or_assign(nonFlake.alias, nonFlake.ref);
 
     return entry;
@@ -385,7 +386,7 @@ LockFile getLockFile(EvalState & evalState, FlakeRef & flakeRef)
     return lockFile;
 }
 
-void updateLockFile(EvalState & state, Path path)
+void updateLockFile(EvalState & state, const Path & path)
 {
     // 'path' is the path to the local flake repo.
     FlakeRef flakeRef = FlakeRef("file://" + path);
diff --git a/src/libexpr/primops/flake.hh b/src/libexpr/primops/flake.hh
index 73446c908..347dd2077 100644
--- a/src/libexpr/primops/flake.hh
+++ b/src/libexpr/primops/flake.hh
@@ -33,7 +33,7 @@ void makeFlakeValue(EvalState & state, const FlakeRef & flakeRef, bool impureTop
 
 std::shared_ptr<FlakeRegistry> readRegistry(const Path &);
 
-void writeRegistry(const FlakeRegistry &, Path);
+void writeRegistry(const FlakeRegistry &, const Path &);
 
 struct Flake
 {
@@ -75,7 +75,8 @@ struct Dependencies
 
 Dependencies resolveFlake(EvalState &, const FlakeRef &, bool impureTopRef, bool isTopFlake = true);
 
-FlakeRegistry updateLockFile(EvalState &, Flake &);
+FlakeRegistry updateLockFile(EvalState &, const Flake &);
+
+void updateLockFile(EvalState &, const Path & path);
 
-void updateLockFile(EvalState &, Path path);
 }