Implement Java.add_to_classpath

CHANGELOG.md

@@ -3,6 +3,7 @@
 New features:
 
 * Foreign strings now have all methods of Ruby `String`. They are treated as `#frozen?` UTF-8 Ruby Strings.
+* Add `Java.add_to_classpath` method to add jar paths at runtime (#2693, @bjfish).
 
 Bug fixes:
 

spec/tags/truffle/interop/add_to_classpath_tags.txt

@@ -0,0 +1 @@
+slow:Java.add_to_classpath loads a jar file

spec/truffle/interop/add_to_classpath_spec.rb

@@ -0,0 +1,29 @@
+# Copyright (c) 2022, 2022 Oracle and/or its affiliates. All rights reserved. This
+# code is released under a tri EPL/GPL/LGPL license. You can use it,
+# redistribute it and/or modify it under the terms of the:
+#
+# Eclipse Public License version 2.0, or
+# GNU General Public License version 2, or
+# GNU Lesser General Public License version 2.1.
+
+require_relative '../../ruby/spec_helper'
+
+guard -> { !TruffleRuby.native? } do
+  describe "Java.add_to_classpath" do
+    before :all do
+      jar_dir = File.expand_path(File.dirname(__FILE__)) + '/fixtures/examplejar'
+      bin_dir = TruffleRuby.graalvm_home + '/bin'
+      Dir.chdir(jar_dir) do
+        system("#{bin_dir}/javac org/truffleruby/examplejar/Example.java")
+        system("#{bin_dir}/jar cf example.jar org/truffleruby/examplejar/Example.class")
+      end
+      @jar_file = jar_dir + '/example.jar'
+    end
+
+    it "loads a jar file" do
+      Java.add_to_classpath(@jar_file).should == true
+      example_object = Java.type('org.truffleruby.examplejar.Example').new
+      example_object.hello("Spec").should == "Hello Spec"
+    end
+  end
+end

spec/truffle/interop/fixtures/examplejar/org/truffleruby/examplejar/Example.java

@@ -0,0 +1,9 @@
+package org.truffleruby.examplejar;
+
+public class Example {
+
+    public String hello(String name){
+        return "Hello " + name;
+    }
+
+}

src/main/java/org/truffleruby/interop/InteropNodes.java

@@ -54,6 +54,7 @@
 import org.truffleruby.language.control.RaiseException;
 import org.truffleruby.language.dispatch.DispatchNode;
 import org.truffleruby.language.library.RubyStringLibrary;
+import org.truffleruby.language.loader.FileLoader;
 import org.truffleruby.language.objects.LogicalClassNode;
 import org.truffleruby.shared.TruffleRuby;
 
@@ -1767,6 +1768,27 @@ private Object javaType(String name) {
             return env.lookupHostSymbol(name);
         }
 
+    }
+
+    @Primitive(name = "java_add_to_classpath")
+    public abstract static class JavaAddToClasspathNode extends PrimitiveArrayArgumentsNode {
+
+        @TruffleBoundary
+        @Specialization(guards = "strings.isRubyString(path)")
+        protected boolean javaAddToClasspath(Object path,
+                @CachedLibrary(limit = "LIBSTRING_CACHE") RubyStringLibrary strings) {
+            TruffleLanguage.Env env = getContext().getEnv();
+            try {
+                TruffleFile file = FileLoader.getSafeTruffleFile(getLanguage(), getContext(),
+                        strings.getJavaString(path));
+                env.addToHostClassPath(file);
+                return true;
+            } catch (SecurityException e) {
+                throw new RaiseException(getContext(),
+                        coreExceptions().securityError("unable to add to classpath", this), e);
+            }
+        }
+
     }
     // endregion
 

src/main/java/org/truffleruby/language/loader/FileLoader.java

@@ -77,7 +77,7 @@ public Pair<Source, Rope> loadFile(String path) throws IOException {
         return Pair.create(source, sourceRope);
     }
 
-    static TruffleFile getSafeTruffleFile(RubyLanguage language, RubyContext context, String path) {
+    public static TruffleFile getSafeTruffleFile(RubyLanguage language, RubyContext context, String path) {
         final Env env = context.getEnv();
         final TruffleFile file;
         try {

src/main/ruby/truffleruby/core/truffle/polyglot.rb

@@ -535,6 +535,10 @@ class ForeignException < Exception # rubocop:disable Lint/InheritException
 end
 
 module Java
+  def self.add_to_classpath(path)
+    Primitive.java_add_to_classpath(path)
+  end
+
   def self.type(name)
     Truffle::Interop.java_type(name)
   end