working autocxx local demo

Author: miguelraz

exercise-templates/cpp-interop/Cargo.toml

@@ -4,3 +4,9 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+autocxx = "0.27.0"
+cxx = "1.0.78"
+
+[build-dependencies]
+autocxx-build = "0.27.0"
+miette = { version = "5", features = ["fancy"] } # optional but gives nicer error messages!

exercise-templates/cpp-interop/build.rs

@@ -0,0 +1,17 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+fn main() -> miette::Result<()> {
+    let path = std::path::PathBuf::from("src");
+    let mut b = autocxx_build::Builder::new("src/main.rs", [&path]).build()?;
+    b.flag_if_supported("-std=c++14").compile("autocxx-demo");
+
+    println!("cargo:rerun-if-changed=src/main.rs");
+    println!("cargo:rerun-if-changed=src/input.h");
+    Ok(())
+}

exercise-templates/cpp-interop/src/input.h

@@ -0,0 +1,35 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#pragma once
+
+#include <cstdint>
+#include <sstream>
+#include <stdint.h>
+#include <string>
+
+class Goat {
+public:
+    Goat() : horns(0) {}
+    void add_a_horn();
+    std::string describe() const;
+private:
+    uint32_t horns;
+};
+
+inline uint32_t DoMath(uint32_t a) {
+    return a * 3;
+}
+
+inline void Goat::add_a_horn() { horns++; }
+inline std::string Goat::describe() const {
+    std::ostringstream oss;
+    std::string plural = horns == 1 ? "" : "s";
+    oss << "This goat has " << horns << " horn" << plural << ".";
+    return oss.str();
+}

exercise-templates/cpp-interop/src/main.rs

@@ -1,3 +1,26 @@
-fn main() {
-    println!("Hello, world!");
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use autocxx::prelude::*;
+include_cpp! {
+    #include "input.h"
+    safety!(unsafe_ffi)
+    generate!("DoMath")
+    generate!("Goat")
 }
+
+fn main() {
+    println!("Hello, world! - C++ math should say 12={}", ffi::DoMath(4));
+    let mut goat = ffi::Goat::new().within_box();
+    goat.as_mut().add_a_horn();
+    goat.as_mut().add_a_horn();
+    assert_eq!(
+        goat.describe().as_ref().unwrap().to_string_lossy(),
+        "This goat has 2 horns."
+    );
+}