Add support for feature selection

README.md

@@ -152,6 +152,10 @@ The pairs can also be generator expressions, as they will be evaluated using $<G
 For example this may be useful if the build scripts of crates look for environment variables.
 This feature requires CMake >= 3.19.0.
 
+Cargo crates sometimes offer features, which traditionally can be specified with `cargo build` on the
+command line as opt-in. You can select the features to use for a crate imported with Corrosion by
+setting the `CORROSION_FEATURES` target list property on the targets created by `corrosion_import_crate`.
+
 ### Developer/Maintainer Options
 These options are not used in the course of normal Corrosion usage, but are used to configure how
 Corrosion is built and installed. Only applies to Corrosion builds and subdirectory uses.

cmake/Corrosion.cmake

@@ -173,6 +173,9 @@ function(_add_cargo_build)
 
     if (CMAKE_VERSION VERSION_GREATER_EQUAL 3.19.0)
         set(build_env_variable_genex "$<GENEX_EVAL:$<TARGET_PROPERTY:${target_name},CORROSION_ENVIRONMENT_VARIABLES>>")
+
+        set(features_target_property "$<GENEX_EVAL:$<TARGET_PROPERTY:${target_name},CORROSION_FEATURES>>")
+        set(features_genex "$<$<BOOL:${features_target_property}>:--features=$<JOIN:${features_target_property},$<COMMA>>>")
 
         set(if_not_host_build_condition "$<NOT:$<BOOL:$<TARGET_PROPERTY:${target_name},CORROSION_USE_HOST_BUILD>>>")
 
@@ -192,7 +195,6 @@ function(_add_cargo_build)
         endif()
     endforeach()
 
-
     add_custom_target(
         cargo-build_${target_name}
         ALL
@@ -215,6 +217,7 @@ function(_add_cargo_build)
                 --manifest-path "${path_to_toml}"
                 build-crate
                     $<$<NOT:$<OR:$<CONFIG:Debug>,$<CONFIG:>>>:--release>
+                    ${features_genex}
                     ${cargo_target_option}
                     --package ${package_name}
         # Copy crate artifacts to the binary dir

generator/src/subcommands/build_crate.rs

@@ -9,6 +9,9 @@ const RELEASE: &str = "release";
 const PACKAGE: &str = "package";
 const TARGET: &str = "target";
 
+// build-crate features list
+const FEATURES: &str = "features";
+
 pub fn subcommand() -> App<'static, 'static> {
     SubCommand::with_name(BUILD_CRATE)
         .arg(Arg::with_name(RELEASE).long("release"))
@@ -26,20 +29,35 @@ pub fn subcommand() -> App<'static, 'static> {
                 .required(true)
                 .help("The name of the package being built with cargo"),
         )
+        .arg(
+            Arg::with_name(FEATURES)
+                .long("features")
+                .value_name("features")
+                .takes_value(true)
+                .multiple(true)
+                .require_delimiter(true)
+                .help("Specifies which features of the crate to use"),
+        )
 }
 
 pub fn invoke(
     args: &crate::GeneratorSharedArgs,
     matches: &ArgMatches,
 ) -> Result<(), Box<dyn std::error::Error>> {
     let target = matches.value_of(TARGET).unwrap();
+    let features = matches
+        .values_of(FEATURES)
+        .map_or(Vec::new(), |c| c.collect())
+        .join(" ");
 
     let mut cargo = process::Command::new(&args.cargo_executable);
 
     cargo.args(&[
         "build",
         "--target",
         target,
+        "--features",
+        &features,
         "--package",
         matches.value_of(PACKAGE).unwrap(),
         "--manifest-path",

test/CMakeLists.txt

@@ -20,6 +20,7 @@ add_subdirectory(workspace)
 if (CMAKE_VERSION VERSION_GREATER_EQUAL 3.19.0)
     add_subdirectory(envvar)
     add_subdirectory(hostbuild)
+    add_subdirectory(features)
 endif()
 
 # Config tests don't work if this is the top level directory.

test/features/CMakeLists.txt

@@ -0,0 +1,19 @@
+corrosion_import_crate(MANIFEST_PATH rust/Cargo.toml)
+
+add_executable(features-cpp-exe main.cpp)
+target_link_libraries(features-cpp-exe PUBLIC rust-feature-lib)
+set_property(
+    TARGET features-cpp-exe
+    APPEND
+    PROPERTY app_features myfeature
+)
+set_property(
+    TARGET features-cpp-exe
+    APPEND
+    PROPERTY app_features secondfeature
+)
+set_property(
+    TARGET rust-feature-lib
+    APPEND
+    PROPERTY CORROSION_FEATURES $<TARGET_PROPERTY:features-cpp-exe,app_features>
+)

test/features/main.cpp

@@ -0,0 +1,9 @@
+extern "C" void rust_function(char const *name);
+
+int main(int argc, char **argv) {
+    if (argc < 2) {
+        rust_function("C++");
+    } else {
+        rust_function(argv[1]);
+    }
+}

test/features/rust/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "rust-feature-lib"
+version = "0.1.0"
+authors = ["Andrew Gaspar <andrew.gaspar@outlook.com>"]
+license = "MIT"
+edition = "2018"
+
+[dependencies]
+
+[lib]
+crate-type=["staticlib"]
+
+[features]
+default = []
+myfeature = []
+secondfeature = []

test/features/rust/src/lib.rs

@@ -0,0 +1,16 @@
+#[cfg(feature = "myfeature")]
+use std::os::raw::c_char;
+
+#[no_mangle]
+#[cfg(feature = "myfeature")]
+pub extern "C" fn rust_function(name: *const c_char) {
+    let name = unsafe { std::ffi::CStr::from_ptr(name).to_str().unwrap() };
+    println!("Hello, {}! I'm Rust!", name);
+}
+
+#[no_mangle]
+#[cfg(feature = "secondfeature")]
+pub extern "C" fn rust_second_function(name: *const c_char) {
+    let name = unsafe { std::ffi::CStr::from_ptr(name).to_str().unwrap() };
+    println!("Hello, {}! I'm Rust again!", name);
+}