From c2d7d083d5ee819dd3113dd5bcface1ffe4aa4c6 Mon Sep 17 00:00:00 2001
From: Ivan Petkov <ivanppetkov@gmail.com>
Date: Sun, 26 Dec 2021 17:10:04 -0800
Subject: [PATCH] Add configureCargoCommonVarsHook

---
 lib/buildWithCargo.nix               |  2 ++
 pkgs/configureCargoCommonVarsHook.sh | 15 +++++++++++++++
 pkgs/default.nix                     |  5 +++++
 3 files changed, 22 insertions(+)
 create mode 100644 pkgs/configureCargoCommonVarsHook.sh

diff --git a/lib/buildWithCargo.nix b/lib/buildWithCargo.nix
index 72177bf..25b102c 100644
--- a/lib/buildWithCargo.nix
+++ b/lib/buildWithCargo.nix
@@ -1,4 +1,5 @@
 { cargo
+, configureCargoCommonVarsHook
 , configureCargoVendoredDepsHook
 , lib
 , stdenv
@@ -8,6 +9,7 @@ args@{ nativeBuildInputs ? [ ], ... }:
 stdenv.mkDerivation (args // {
   nativeBuildInputs = nativeBuildInputs ++ [
     cargo
+    configureCargoCommonVarsHook
     configureCargoVendoredDepsHook
   ];
 
diff --git a/pkgs/configureCargoCommonVarsHook.sh b/pkgs/configureCargoCommonVarsHook.sh
new file mode 100644
index 0000000..c62bdda
--- /dev/null
+++ b/pkgs/configureCargoCommonVarsHook.sh
@@ -0,0 +1,15 @@
+configureCargoCommonVars() {
+  echo "Executing configureCargoCommonVars"
+
+  export CARGO_BUILD_JOBS=${CARGO_BUILD_JOBS:-$NIX_BUILD_CORES}
+  export RUST_TEST_THREADS=${RUST_TEST_THREADS:-$NIX_BUILD_CORES}
+
+  # Disable incremental builds by default since we don't get a ton of benefit
+  # while building with nix. Allow a declared-but-empty variable which will tell
+  # cargo to honor the definition used in the build profile
+  export CARGO_BUILD_INCREMENTAL=${CARGO_BUILD_INCREMENTAL-false}
+
+  echo "Finished configureCargoCommonVars"
+}
+
+preConfigureHooks+=(configureCargoCommonVars)
diff --git a/pkgs/default.nix b/pkgs/default.nix
index d0a1e59..d749198 100644
--- a/pkgs/default.nix
+++ b/pkgs/default.nix
@@ -1,6 +1,11 @@
 { makeSetupHook }:
 
 {
+  configureCargoCommonVarsHook = makeSetupHook
+    {
+      name = "configureCargoCommonVarsHook";
+    } ./configureCargoCommonVarsHook.sh;
+
   configureCargoVendoredDepsHook = makeSetupHook
     {
       name = "configureCargoVendoredDepsHook";