gpui: make build dependencies mac only

This removes bindgen and cbindgen from the dependency graph on non-macos
systems, improving compile times on those systems.

Signed-off-by: Niklas Wimmer <mail@nwimmer.me>

crates/gpui/Cargo.toml

@@ -78,7 +78,7 @@ backtrace = "0.3"
 collections = { workspace = true, features = ["test-support"] }
 util = { workspace = true, features = ["test-support"] }
 
-[build-dependencies]
+[target.'cfg(target_os = "macos")'.build-dependencies]
 bindgen = "0.65.1"
 cbindgen = "0.26.0"
 

crates/gpui/build.rs

@@ -1,29 +1,36 @@
 #![cfg_attr(any(not(target_os = "macos"), feature = "macos-blade"), allow(unused))]
 
-use std::{
-    env,
-    path::{Path, PathBuf},
-};
-
-use cbindgen::Config;
-
 //TODO: consider generating shader code for WGSL
 //TODO: deprecate "runtime-shaders" and "macos-blade"
 
 fn main() {
     #[cfg(target_os = "macos")]
-    generate_dispatch_bindings();
-    #[cfg(all(target_os = "macos", not(feature = "macos-blade")))]
-    let header_path = generate_shader_bindings();
-    #[cfg(all(target_os = "macos", not(feature = "macos-blade")))]
-    #[cfg(feature = "runtime_shaders")]
-    emit_stitched_shaders(&header_path);
-    #[cfg(all(target_os = "macos", not(feature = "macos-blade")))]
-    #[cfg(not(feature = "runtime_shaders"))]
-    compile_metal_shaders(&header_path);
+    macos::build();
 }
 
-fn generate_dispatch_bindings() {
+#[cfg(target_os = "macos")]
+mod macos {
+    use std::{
+        env,
+        path::{Path, PathBuf},
+    };
+
+    use cbindgen::Config;
+
+    pub(super) fn build() {
+        generate_dispatch_bindings();
+        #[cfg(not(feature = "macos-blade"))]
+        {
+            let header_path = generate_shader_bindings();
+
+            #[cfg(feature = "runtime_shaders")]
+            emit_stitched_shaders(&header_path);
+            #[cfg(not(feature = "runtime_shaders"))]
+            compile_metal_shaders(&header_path);
+        }
+    }
+
+    fn generate_dispatch_bindings() {
         println!("cargo:rustc-link-lib=framework=System");
         println!("cargo:rerun-if-changed=src/platform/mac/dispatch.h");
 
@@ -54,9 +61,9 @@ fn generate_dispatch_bindings() {
         bindings
             .write_to_file(out_path.join("dispatch_sys.rs"))
             .expect("couldn't write dispatch bindings");
-}
+    }
 
-fn generate_shader_bindings() -> PathBuf {
+    fn generate_shader_bindings() -> PathBuf {
         let output_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("scene.h");
         let crate_dir = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap());
         let mut config = Config::default();
@@ -114,18 +121,19 @@ fn generate_shader_bindings() -> PathBuf {
             .write_to_file(&output_path);
 
         output_path
-}
+    }
 
-/// To enable runtime compilation, we need to "stitch" the shaders file with the generated header
-/// so that it is self-contained.
-#[cfg(feature = "runtime_shaders")]
-fn emit_stitched_shaders(header_path: &Path) {
+    /// To enable runtime compilation, we need to "stitch" the shaders file with the generated header
+    /// so that it is self-contained.
+    #[cfg(feature = "runtime_shaders")]
+    fn emit_stitched_shaders(header_path: &Path) {
         use std::str::FromStr;
         fn stitch_header(header: &Path, shader_path: &Path) -> std::io::Result<PathBuf> {
             let header_contents = std::fs::read_to_string(header)?;
             let shader_contents = std::fs::read_to_string(shader_path)?;
             let stitched_contents = format!("{header_contents}\n{shader_contents}");
-        let out_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("stitched_shaders.metal");
+            let out_path =
+                PathBuf::from(env::var("OUT_DIR").unwrap()).join("stitched_shaders.metal");
             std::fs::write(&out_path, stitched_contents)?;
             Ok(out_path)
         }
@@ -133,13 +141,15 @@ fn emit_stitched_shaders(header_path: &Path) {
         let shader_path = PathBuf::from_str(shader_source_path).unwrap();
         stitch_header(header_path, &shader_path).unwrap();
         println!("cargo:rerun-if-changed={}", &shader_source_path);
-}
-#[cfg(not(feature = "runtime_shaders"))]
-fn compile_metal_shaders(header_path: &Path) {
+    }
+
+    #[cfg(not(feature = "runtime_shaders"))]
+    fn compile_metal_shaders(header_path: &Path) {
         use std::process::{self, Command};
         let shader_path = "./src/platform/mac/shaders.metal";
         let air_output_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("shaders.air");
-    let metallib_output_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("shaders.metallib");
+        let metallib_output_path =
+            PathBuf::from(env::var("OUT_DIR").unwrap()).join("shaders.metallib");
         println!("cargo:rerun-if-changed={}", shader_path);
 
         let output = Command::new("xcrun")
@@ -183,4 +193,5 @@ fn compile_metal_shaders(header_path: &Path) {
             );
             process::exit(1);
         }
+    }
 }