nix: switch to crane for incramental builds

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: Ia5ab2f512ffac20722966b605d7eaf156a6a6964

nix/package.nix

@@ -1,28 +1,32 @@
 {
   lib,
-  rustPlatform,
+  craneLib,
 }: let
-  fs = lib.fileset;
+  pname = "eris";
+  inherit ((lib.importTOML ../Cargo.toml).package) version;
+  src = let
+    fs = lib.fileset;
+    s = ../.;
+  in
+    fs.toSource {
+      root = s;
+      fileset = fs.unions [
+        (fs.fileFilter (file: builtins.any file.hasExt ["rs"]) (s + /src))
+        (s + /Cargo.lock)
+        (s + /Cargo.toml)
+      ];
+    };
 
-  lockfile = ../Cargo.lock;
-  cargoToml = ../Cargo.toml;
+  cargoArtifacts = craneLib.buildDepsOnly {
+    name = "${pname}-deps";
+    strictDeps = true;
+    inherit src;
+  };
 in
-  rustPlatform.buildRustPackage {
-    pname = "eris";
-    version = "0.0.1";
+  craneLib.buildPackage {
+    inherit pname src version cargoArtifacts;
 
-    src = let
-      s = ../.;
-    in
-      fs.toSource {
-        root = s;
-        fileset = fs.unions [
-          (fs.fileFilter (file: builtins.any file.hasExt ["rs"]) (s + /src))
-          (s + /contrib)
-          lockfile
-          cargoToml
-        ];
-      };
+    strictDeps = true;
 
     postInstall = ''
       mkdir -p $out/share/contrib
@@ -30,10 +34,10 @@ in
       cp -rv $src/contrib/lua $out/share/contrib
     '';
 
-    cargoLock.lockFile = lockfile;
-
     meta = {
       description = "Sophisticated HTTP tarpit and honeypot stream";
+      homepage = "https://git.frzn.dev/NotAShelf/eris";
+      maintainers = [lib.maintainers.NotAShelf];
       mainProgram = "eris";
     };
   }