Add NativeLibraryFinder

Author: Akirathan

engine/runtime/src/main/java/org/enso/interpreter/runtime/HostClassLoader.java

@@ -81,6 +81,31 @@ protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundE
     }
   }
 
+  /**
+   * Find the library with the specified name inside the {@code polyglot/lib} directory of caller's
+   * project. The search inside the {@code polyglot/lib} directory hierarchy is specified by <a
+   * href="https://bits.netbeans.org/23/javadoc/org-openide-modules/org/openide/modules/doc-files/api.html#jni">NetBeans
+   * JNI specification</a>.
+   *
+   * <p>Note: The current implementation iterates all the {@code polyglot/lib} directories of all
+   * the packages.
+   *
+   * @param libname The library name. Without platform-specific suffix or prefix.
+   * @return Absolute path to the library if found, or null.
+   */
+  @Override
+  protected String findLibrary(String libname) {
+    var pkgRepo = EnsoContext.get(null).getPackageRepository();
+    for (var pkg : pkgRepo.getLoadedPackagesJava()) {
+      var libPath = NativeLibraryFinder.findNativeLibrary(libname, pkg);
+      if (libPath != null) {
+        return libPath;
+      }
+    }
+    logger.trace("Native library {} not found in any package", libname);
+    return null;
+  }
+
   @Override
   public void close() {
     loadedClasses.clear();

engine/runtime/src/main/java/org/enso/interpreter/runtime/NativeLibraryFinder.java

@@ -0,0 +1,53 @@
+package org.enso.interpreter.runtime;
+
+import com.oracle.truffle.api.TruffleFile;
+import java.util.Locale;
+import org.enso.pkg.Package;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Helper class to find native libraries in packages. The search algorithm complies to the <a
+ * href="https://bits.netbeans.org/23/javadoc/org-openide-modules/org/openide/modules/doc-files/api.html#jni">NetBeans
+ * JNI specification</a>.
+ */
+final class NativeLibraryFinder {
+
+  private static final Logger logger = LoggerFactory.getLogger(NativeLibraryFinder.class);
+
+  private NativeLibraryFinder() {}
+
+  /**
+   * Tries to find native library in the given package.
+   *
+   * @param libName the name of the library to find, without platform specific prefix or suffix.
+   * @param pkg the package to search in.
+   * @return null if not found, absolute path otherwise.
+   */
+  static String findNativeLibrary(String libName, Package<TruffleFile> pkg) {
+    var arch = System.getProperty("os.arch");
+    var osName = System.getProperty("os.name").toLowerCase(Locale.ENGLISH);
+    var libNameWithSuffix = System.mapLibraryName(libName);
+    var libDir = pkg.polyglotDir().resolve("lib");
+    if (!libDir.exists()) {
+      logger.trace("Native library directory {} does not exist", libDir);
+      return null;
+    }
+    var nativeLib = libDir.resolve(libNameWithSuffix);
+    if (nativeLib.exists()) {
+      logger.trace("Found native library {}", nativeLib);
+      return nativeLib.getAbsoluteFile().getPath();
+    }
+    nativeLib = libDir.resolve(arch).resolve(libNameWithSuffix);
+    if (nativeLib.exists()) {
+      logger.trace("Found native library {}", nativeLib);
+      return nativeLib.getAbsoluteFile().getPath();
+    }
+    nativeLib = libDir.resolve(arch).resolve(osName).resolve(libNameWithSuffix);
+    if (nativeLib.exists()) {
+      logger.trace("Found native library {}", nativeLib);
+      return nativeLib.getAbsoluteFile().getPath();
+    }
+    return null;
+  }
+}