Move project common code into include

native/src/include/consts.rs

@@ -0,0 +1,8 @@
+// Expose constant strings as macros so that we can use concat!() on these values
+
+#[macro_export]
+macro_rules! LOGFILE {
+    () => {
+        "/cache/magisk.log"
+    };
+}

native/src/include/gen.rs

@@ -0,0 +1,45 @@
+// This file hosts shared build script logic
+
+use std::fmt::Display;
+use std::fs::File;
+use std::io::Write;
+use std::path::Path;
+use std::{fs, io, process};
+
+use cxx_gen::Opt;
+
+trait ResultExt<T> {
+    fn ok_or_exit(self) -> T;
+}
+
+impl<T, E: Display> ResultExt<T> for Result<T, E> {
+    fn ok_or_exit(self) -> T {
+        match self {
+            Ok(r) => r,
+            Err(e) => {
+                eprintln!("error occurred: {}", e);
+                process::exit(1);
+            }
+        }
+    }
+}
+
+fn write_if_diff<P: AsRef<Path>>(path: P, bytes: &[u8]) -> io::Result<()> {
+    let path = path.as_ref();
+    if let Ok(orig) = fs::read(path) {
+        // Do not modify the file if content is the same to make incremental build more optimal
+        if orig.as_slice() == bytes {
+            return Ok(());
+        }
+    }
+    let mut f = File::create(path)?;
+    f.write_all(bytes)
+}
+
+pub fn gen_cxx_binding(name: &str) {
+    println!("cargo:rerun-if-changed=lib.rs");
+    let opt = Opt::default();
+    let gen = cxx_gen::generate_header_and_cc_with_path("lib.rs", &opt);
+    write_if_diff(format!("{}.cpp", name), gen.implementation.as_slice()).ok_or_exit();
+    write_if_diff(format!("{}.hpp", name), gen.header.as_slice()).ok_or_exit();
+}