build: fix build script to run tika-native gradle build inside OUT_DIR

extractous-core/build.rs

@@ -5,21 +5,27 @@ use std::path::{Path, PathBuf};
 use std::process::Command;
 
 fn main() {
-    // Main build output directory
-    let out_dir = env::var("OUT_DIR").map(PathBuf::from).unwrap();
-    let jdk_install_dir = out_dir.join("graalvm-jdk"); // jdk install dir if no JAVA_HOME is set
-    let libs_out_dir = out_dir.join("libs"); // Directory to copy the built shared library to
-
     // Set tika_native source directory and python bindings directory
     let root_dir = env::var("CARGO_MANIFEST_DIR").map(PathBuf::from).unwrap();
-    let tika_native_dir = root_dir.join("tika-native");
+    let tika_native_source_dir = root_dir.join("tika-native");
     // canonicalize does not work on Windows because it returns UNC paths
     //let python_bind_dir = fs::canonicalize("../bindings/extractous-python/python/extractous").unwrap();
     let python_bind_dir = root_dir.join("../bindings/extractous-python/python/extractous");
 
-    // Use JAVA_HOME to find or install GraalVM JDK
+    // Main build output directory
+    let out_dir = env::var("OUT_DIR").map(PathBuf::from).unwrap();
+    let jdk_install_dir = out_dir.join("graalvm-jdk"); // out_dir subdir where jdk is downloaded
+    let libs_out_dir = out_dir.join("libs"); // out_dir subdir to copy the built libs to
+    let tika_native_dir = out_dir.join("tika-native"); // out_dir subdir where the gradle build is run
+
+    // Try to find a GraalVM JDK or install one if not found
     let graalvm_home = get_graalvm_home(&jdk_install_dir);
 
+    // Because build script are not allowed to change files outside of OUT_DIR
+    // we need to copy the tika-native source directory to OUT_DIR and call gradle build there
+    fs_extra::dir::copy(&tika_native_source_dir, &out_dir, &fs_extra::dir::CopyOptions::new())
+        .expect("Failed to copy tika-native source to OUT_DIR");
+
     // Just for debugging
     // let graal_home = env::var("GRAALVM_HOME");
     // let java_home = env::var("JAVA_HOME");
@@ -29,6 +35,7 @@ fn main() {
     // println!("cargo:warning=out_dir: {}", out_dir.display());
     //println!("cargo:warning=tika_native_dir: {:?}", tika_native_dir);
 
+    // Launch the gradle build
     gradle_build(
         &graalvm_home,
         &tika_native_dir,