From 5a92b07f5ddb808f7711166d27d840ae51a99505 Mon Sep 17 00:00:00 2001
From: Colin <colin@uninsane.org>
Date: Sun, 19 May 2024 22:33:00 +0000
Subject: [PATCH] cross: clean up the meson x cargo flag patching

---
 overlays/cross.nix | 68 ++++++++++++++--------------------------------
 1 file changed, 20 insertions(+), 48 deletions(-)

diff --git a/overlays/cross.nix b/overlays/cross.nix
index 09cdf0f1..f8adb9cb 100644
--- a/overlays/cross.nix
+++ b/overlays/cross.nix
@@ -75,8 +75,20 @@ let
       pkg
     );
 
+  # build a GI_TYPELIB_PATH out of some packages, useful for build-time tools which otherwise
+  # try to load gobject-introspection files for the wrong platform (e.g. `blueprint` compiler).
   typelibPath = pkgs: lib.concatStringsSep ":" (builtins.map (p: "${lib.getLib p}/lib/girepository-1.0") pkgs);
 
+  # `cargo` which adds the correct env vars and `--target` flag when invoked from meson build scripts
+  crossCargo = let
+    inherit (final.pkgsBuildHost) cargo;
+    inherit (final.rust.envVars) setEnv rustHostPlatformSpec;
+  in (final.pkgsBuildBuild.writeShellScriptBin "cargo" ''
+    exec ${setEnv} "${lib.getExe cargo}" "$@" --target "${rustHostPlatformSpec}"
+  '').overrideAttrs {
+    inherit (cargo) meta;
+  };
+
 
   emulated = mkEmulated final prev;
 
@@ -474,24 +486,14 @@ in with final; {
   #   ];
   # });
 
-  delfin = prev.delfin.overrideAttrs (upstream:
-  let
-    cargoEnvWrapper = buildPackages.writeShellScript "cargo-env-wrapper" ''
-      CARGO_BIN="$1"
-      shift
-      CARGO_OP="$1"
-      shift
-
-      ${rust.envVars.setEnv} "$CARGO_BIN" "$CARGO_OP" --target "${rust.envVars.rustHostPlatformSpec}" "$@"
-    '';
-  in {
+  delfin = prev.delfin.overrideAttrs (upstream: {
     nativeBuildInputs = upstream.nativeBuildInputs ++ [
       # fixes: loaders/meson.build:72:7: ERROR: Program 'msgfmt' not found or not executable
       buildPackages.gettext
     ];
     postPatch = ''
       substituteInPlace delfin/meson.build \
-        --replace "cargo, 'build'," "'${cargoEnvWrapper}', cargo, 'build'," \
+        --replace "cargo, 'build'," "'${lib.getExe crossCargo}', 'build'," \
         --replace "'delfin' / rust_target" "'delfin' / '${rust.envVars.rustHostPlatformSpec}' / rust_target"
     '';
   });
@@ -745,24 +747,14 @@ in with final; {
   # });
 
   # 2024/02/27: upstreaming is unblocked
-  glycin-loaders = prev.glycin-loaders.overrideAttrs (upstream:
-  let
-    cargoEnvWrapper = buildPackages.writeShellScript "cargo-env-wrapper" ''
-      CARGO_BIN="$1"
-      shift
-      CARGO_OP="$1"
-      shift
-
-      ${rust.envVars.setEnv} "$CARGO_BIN" "$CARGO_OP" --target "${rust.envVars.rustHostPlatformSpec}" "$@"
-    '';
-  in {
+  glycin-loaders = prev.glycin-loaders.overrideAttrs (upstream: {
     nativeBuildInputs = upstream.nativeBuildInputs ++ [
       # fixes: loaders/meson.build:72:7: ERROR: Program 'msgfmt' not found or not executable
       buildPackages.gettext
     ];
     postPatch = ''
       substituteInPlace loaders/meson.build \
-        --replace "cargo_bin, 'build'," "'${cargoEnvWrapper}', cargo_bin, 'build'," \
+        --replace "cargo_bin, 'build'," "'${lib.getExe crossCargo}', 'build'," \
         --replace "'loaders' / rust_target" "'loaders' / '${rust.envVars.rustHostPlatformSpec}' / rust_target"
     '';
   });
@@ -1210,20 +1202,10 @@ in with final; {
   # });
 
   # 2023/12/19: upstreaming blocked on glycin-loaders
-  loupe = prev.loupe.overrideAttrs (upstream:
-  let
-    cargoEnvWrapper = buildPackages.writeShellScript "cargo-env-wrapper" ''
-      CARGO_BIN="$1"
-      shift
-      CARGO_OP="$1"
-      shift
-
-      ${rust.envVars.setEnv} "$CARGO_BIN" "$CARGO_OP" --target "${rust.envVars.rustHostPlatformSpec}" "$@"
-    '';
-  in {
+  loupe = prev.loupe.overrideAttrs (upstream: {
     postPatch = (upstream.postPatch or "") + ''
       substituteInPlace src/meson.build \
-        --replace "cargo, 'build'," "'${cargoEnvWrapper}', cargo, 'build'," \
+        --replace "cargo, 'build'," "'${lib.getExe crossCargo}', 'build'," \
         --replace "'src' / rust_target" "'src' / '${rust.envVars.rustHostPlatformSpec}' / rust_target"
     '';
   });
@@ -1845,21 +1827,11 @@ in with final; {
   #   inherit (emulated) stdenv;
   # };
 
-  snapshot = prev.snapshot.overrideAttrs (upstream:
-  let
-    cargoEnvWrapper = buildPackages.writeShellScript "cargo-env-wrapper" ''
-      CARGO_BIN="$1"
-      shift
-      CARGO_OP="$1"
-      shift
-
-      ${rust.envVars.setEnv} "$CARGO_BIN" "$CARGO_OP" --target "${rust.envVars.rustHostPlatformSpec}" "$@"
-    '';
-  in {
+  snapshot = prev.snapshot.overrideAttrs (upstream: {
     # fixes "error: linker `cc` not found"
     postPatch = (upstream.postPatch or "") + ''
       substituteInPlace src/meson.build \
-        --replace "cargo, 'build'," "'${cargoEnvWrapper}', cargo, 'build'," \
+        --replace "cargo, 'build'," "'${lib.getExe crossCargo}', 'build'," \
         --replace "'src' / rust_target" "'src' / '${rust.envVars.rustHostPlatformSpec}' / rust_target"
     '';
   });