Add support of Class.getDeclaringClass()

tests/integration_tests.rs

@@ -654,3 +654,23 @@ Interfaces implemented by int:
 "#,
     );
 }
+
+#[test]
+fn should_return_declaring_class() {
+    assert_success(
+        "samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample",
+        r#"double: null
+[Ljava.lang.String;: null
+samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample: null
+samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample$TopLevel: class samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample
+samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample$SimpleNested$Inner: class samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample$SimpleNested
+samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample$SimpleNested$StaticNested: class samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample$SimpleNested
+samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample$1: null
+samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample$1LocalClass: null
+samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample$1StaticMethodInner: null
+samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample$DeepNesting$Inner: class samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample$DeepNesting
+samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample$DeepNesting$Inner$DeepInner: class samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample$DeepNesting$Inner
+samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample$DeepNesting$Inner$DeepInner: class samples.reflection.trivial.classgetdeclaringclassexample.GetDeclaringClassExample$DeepNesting$Inner
+"#,
+    );
+}

tests/test_data/GetDeclaringClassExample.java

@@ -0,0 +1,72 @@
+package samples.reflection.trivial.classgetdeclaringclassexample;
+
+public class GetDeclaringClassExample {
+    public static class TopLevel {
+    }
+
+    public static class SimpleNested {
+        public class Inner {
+        }
+
+        public static class StaticNested {
+        }
+    }
+
+    public static void main(String[] args) {
+        print(double.class);
+
+        print(String[].class);
+
+        print(GetDeclaringClassExample.class);
+
+        print(TopLevel.class);
+
+        print(SimpleNested.Inner.class);
+
+        print(SimpleNested.StaticNested.class);
+
+        Runnable anonymous = new Runnable() {
+            @Override
+            public void run() {
+            }
+        };
+        print(anonymous.getClass());
+
+        class LocalClass {
+        }
+        print(LocalClass.class);
+
+        testStaticMethodInner();
+
+        DeepNesting outer = new DeepNesting();
+        DeepNesting.Inner inner = outer.new Inner();
+        DeepNesting.Inner.DeepInner deepInner = inner.new DeepInner();
+        print(DeepNesting.Inner.class);
+        print(DeepNesting.Inner.DeepInner.class);
+        print(deepInner.getClass());
+
+//         Runnable lambda = () -> {
+//         };
+//         print(lambda.getClass()); // Execution Error: Unknown reference opcode: 186
+    }
+
+    private static void testStaticMethodInner() {
+        class StaticMethodInner {
+        }
+        print(StaticMethodInner.class);
+    }
+
+    static class DeepNesting {
+        public class Inner {
+            public class DeepInner {
+            }
+        }
+    }
+
+    private static void print(Class<?> clazz) {
+        System.out.print(clazz.getName());
+        System.out.print(": ");
+        System.out.println(clazz.getDeclaringClass());
+    }
+
+}

vm/src/execution_engine/system_native_table.rs

@@ -2,7 +2,7 @@ use crate::error::Error;
 use crate::execution_engine::system_native_table::NativeMethod::{Basic, WithStackFrames};
 use crate::helper::i64_to_vec;
 use crate::stack::stack_frame::StackFrames;
-use crate::system_native::class::{class_init_class_name_wrp, for_name0_wrp, get_modifiers_wrp, get_primitive_class_wrp, is_array_wrp, is_interface_wrp, is_primitive_wrp, get_superclass_wrp, get_interfaces0_wrp};
+use crate::system_native::class::{class_init_class_name_wrp, for_name0_wrp, get_modifiers_wrp, get_primitive_class_wrp, is_array_wrp, is_interface_wrp, is_primitive_wrp, get_superclass_wrp, get_interfaces0_wrp, get_declaring_class0_wrp};
 use crate::system_native::file_descriptor::{file_descriptor_close0_wrp, get_handle_wrp};
 use crate::system_native::file_output_stream::{
     file_output_stream_open0_wrp, file_output_stream_write_bytes_wrp, file_output_stream_write_wrp,
@@ -94,6 +94,10 @@ static SYSTEM_NATIVE_TABLE: Lazy<HashMap<&'static str, NativeMethod>> = Lazy::ne
         "java/lang/Class:getInterfaces0:()[Ljava/lang/Class;",
         Basic(get_interfaces0_wrp),
     );
+    table.insert(
+        "java/lang/Class:getDeclaringClass0:()Ljava/lang/Class;",
+        Basic(get_declaring_class0_wrp),
+    );
     table.insert(
         "jdk/internal/misc/Unsafe:registerNatives:()V",
         Basic(void_stub),

vm/src/method_area/attributes_helper.rs

@@ -1,4 +1,4 @@
-use jclass::attributes::Attribute;
+use jclass::attributes::{Attribute, InnerClassRecord};
 use std::collections::HashMap;
 
 pub struct AttributesHelper {
@@ -109,6 +109,14 @@ impl AttributesHelper {
             _ => None,
         }
     }
+
+    pub fn get_inner_class_records(&self) -> Option<Vec<InnerClassRecord>> {
+        match self.data.get(&AttributeType::InnerClasses)? {
+            Attribute::InnerClasses { classes } => Some(classes.clone()),
+            _ => None,
+        }
+    }
+
 }
 
 #[cfg(test)]

vm/src/method_area/java_class.rs

@@ -32,6 +32,7 @@ pub(crate) struct JavaClass {
 
     instance_fields_hierarchy: OnceCell<IndexMap<ClassName, IndexMap<FieldNameType, Field>>>,
     fields_offset_mapping: OnceCell<IndexSet<FullyQualifiedFieldName>>,
+    declaring_class: Option<String>,
 }
 
 #[derive(Debug)]
@@ -71,6 +72,7 @@ impl JavaClass {
         parent: Option<String>,
         interfaces: IndexSet<String>,
         access_flags: u16,
+        declaring_class: Option<String>,
     ) -> Self {
         let external_name = PRIMITIVE_TYPE_BY_CODE
             .get(this_class_name)
@@ -90,6 +92,7 @@ impl JavaClass {
             static_fields_initialized: AtomicBool::new(false),
             instance_fields_hierarchy: OnceCell::new(),
             fields_offset_mapping: OnceCell::new(),
+            declaring_class,
         }
     }
 
@@ -235,6 +238,10 @@ impl JavaClass {
     pub fn external_name(&self) -> &str {
         &self.external_name
     }
+
+    pub fn declaring_class(&self) -> &Option<String> {
+        &self.declaring_class
+    }
 }
 
 impl Methods {

vm/src/method_area/method_area.rs

@@ -19,6 +19,7 @@ use std::io::Read;
 use std::path::{Path, PathBuf};
 use std::sync::{Arc, RwLock};
 use tracing::trace;
+use jclass::attributes::Attribute;
 
 static METHOD_AREA: OnceCell<MethodArea> = OnceCell::new();
 
@@ -163,6 +164,12 @@ impl MethodArea {
 
         let access_flags = class_file.access_flags().bits();
 
+        let declaring_class = Self::get_declaring_class(
+            &class_file.attributes(),
+            &cpool_helper,
+            class_name.as_str(),
+        );
+
         Ok((
             class_name.clone(),
             Arc::new(JavaClass::new(
@@ -174,6 +181,7 @@ impl MethodArea {
                 super_class_name,
                 interface_names,
                 access_flags,
+                declaring_class,
             )),
         ))
     }
@@ -451,6 +459,7 @@ impl MethodArea {
             None,
             IndexSet::new(),
             PUBLIC | FINAL | ABSTRACT,
+            None,
         ))
     }
 
@@ -467,6 +476,7 @@ impl MethodArea {
             Some("java/lang/Object".to_string()),
             IndexSet::from(["java/lang/Cloneable".to_string(), "java/io/Serializable".to_string()]),
             PUBLIC | FINAL | ABSTRACT,
+            None,
         ))
     }
 
@@ -503,4 +513,27 @@ impl MethodArea {
         *guard = Some(thread_id);
         Ok(())
     }
+
+    fn get_declaring_class(
+        attributes: &[Attribute],
+        cpool_helper: &CPoolHelper,
+        class_name: &str,
+    ) -> Option<String> {
+        let attribute_helper = AttributesHelper::new(attributes);
+        let inner_class_records = attribute_helper.get_inner_class_records()?;
+
+        inner_class_records.iter().find_map(|inner_class_record| {
+            let inner_class_info_index = inner_class_record.inner_class_info_index();
+            let inner_class_info = cpool_helper.get_class_name(inner_class_info_index)?;
+
+            if class_name == inner_class_info {
+                let outer_class_info_index = inner_class_record.outer_class_info_index();
+                let outer_class_info = cpool_helper.get_class_name(outer_class_info_index)?;
+
+                Some(outer_class_info)
+            } else {
+                None
+            }
+        })
+    }
 }

vm/src/system_native/class.rs

@@ -194,3 +194,27 @@ fn get_interfaces0(class_ref: i32) -> crate::error::Result<i32> {
     });
     Ok(result_ref)
 }
+
+pub(crate) fn get_declaring_class0_wrp(args: &[i32]) -> crate::error::Result<Vec<i32>> {
+    let clazz_ref = args[0];
+    let declaring_class_ref = get_declaring_class0(clazz_ref)?;
+    Ok(vec![declaring_class_ref])
+}
+fn get_declaring_class0(clazz_ref: i32) -> crate::error::Result<i32> {
+    let declaring_class_ref = with_method_area(|method_area| {
+        let class_name = method_area.get_from_reflection_table(clazz_ref)?;
+        let jc = method_area.get(&class_name)?;
+        let declaring_class_ref = jc
+            .declaring_class()
+            .as_ref()
+            .map(|declaring_class| {
+                let declaring_class_ref = method_area.load_reflection_class(declaring_class);
+                declaring_class_ref
+            })
+            .unwrap_or(Ok(0));
+
+        declaring_class_ref
+    });
+
+    declaring_class_ref
+}