Clean up generated C++ include directory handling

Don't generate the headers by default in the source directory, put them
into a sub-directory in OUT_DIR instead and convey that location via
links to the C++ test driver.

.gitignore

@@ -4,4 +4,3 @@ node_modules
 tools/figma_import/target
 tools/figma_import/figma_output
 *.code-workspace
-api/sixtyfps-cpp/generated_include

api/sixtyfps-cpp/Cargo.toml

@@ -9,6 +9,8 @@ description = "SixtyFPS C++ integration"
 repository = "https://github.com/sixtyfpsui/sixtyfps"
 homepage = "https://sixtyfps.io"
 publish = false
+# prefix used to convey path to generated includes to the C++ test driver
+links = "sixtyfps_cpp"
 
 [lib]
 path = "lib.rs"

api/sixtyfps-cpp/build.rs

@@ -20,8 +20,12 @@ fn main() -> Result<(), anyhow::Error> {
         manifest_dir.to_string_lossy()
     ));
 
-    let output_dir = std::env::var_os("SIXTYFPS_GENERATED_INCLUDE_DIR")
+    let output_dir = std::env::var_os("SIXTYFPS_GENERATED_INCLUDE_DIR").unwrap_or_else(|| {
-        .unwrap_or_else(|| Path::new(&manifest_dir).join("generated_include").into());
+        Path::new(&std::env::var_os("OUT_DIR").unwrap()).join("generated_include").into()
+    });
+    let output_dir = Path::new(&output_dir);
 
-    cbindgen::gen_all(&root_dir, &Path::new(&output_dir))
+    println!("cargo:GENERATED_INCLUDE_DIR={}", output_dir.display());
+
+    cbindgen::gen_all(&root_dir, &output_dir)
 }

tests/driver/cpp/Cargo.toml

@@ -10,9 +10,11 @@ license = "GPL-3.0-only"
 path = "main.rs"
 name = "test-driver-cpp"
 
+[dependencies]
+sixtyfps-cpp = { path = "../../../api/sixtyfps-cpp", features = ["testing"] }
+
 [dev-dependencies]
 sixtyfps-compilerlib = { path = "../../../sixtyfps_compiler", features = ["cpp", "display-diagnostics"] }
-sixtyfps-cpp = { path = "../../../api/sixtyfps-cpp", features = ["testing"] }
 cc = "1.0.54"
 tempfile = "3"
 scopeguard = "1.1.0"

tests/driver/cpp/build.rs

@@ -8,7 +8,7 @@
     Please contact info@sixtyfps.io for more information.
 LICENSE END */
 use std::io::Write;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 
 /// The root dir of the git repository
 fn root_dir() -> PathBuf {
@@ -34,15 +34,17 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     println!("cargo:rustc-env=CPP_LIB_PATH={}", target_dir.display());
 
+    let generated_include_dir = std::env::var_os("DEP_SIXTYFPS_CPP_GENERATED_INCLUDE_DIR")
+        .expect("the sixtyfps-cpp crate needs to provide the meta-data that points to the directory with the generated includes");
+    println!(
+        "cargo:rustc-env=GENERATED_CPP_HEADERS_PATH={}",
+        Path::new(&generated_include_dir).display()
+    );
     let root_dir = root_dir();
     println!(
         "cargo:rustc-env=CPP_API_HEADERS_PATH={}/api/sixtyfps-cpp/include",
         root_dir.display()
     );
-    println!(
-        "cargo:rustc-env=GENERATED_CPP_HEADERS_PATH={}/api/sixtyfps-cpp/generated_include",
-        root_dir.display()
-    );
 
     let tests_file_path =
         std::path::Path::new(&std::env::var_os("OUT_DIR").unwrap()).join("test_functions.rs");