Test default interface stub generation (#4431)

Author: shai-almog

vm/ByteCodeTranslator/src/com/codename1/tools/translator/ByteCodeClass.java

@@ -977,9 +977,12 @@ public String generateCCode(List<ByteCodeClass> allClasses) {
                 }
             }
         }
-        if(baseClassObject != null) {
+        if(!isInterface) {
             List<BytecodeMethod> bm = new ArrayList<BytecodeMethod>(methods);
-            appendSuperStub(b, bm, baseClassObject);
+            if(baseClassObject != null) {
+                appendSuperStub(b, bm, baseClassObject);
+            }
+            appendDefaultInterfaceStubs(b, bm);
         }
         int offset = 0;
         if(clsName.equals("java_lang_Class")) {
@@ -1198,6 +1201,50 @@ private void appendSuperStub(StringBuilder b, List<BytecodeMethod> bm, ByteCodeC
         }
         BytecodeMethod.setAcceptStaticOnEquals(false);
     }
+
+    private boolean hasMethodInBaseClass(BytecodeMethod method) {
+        if(baseClassObject == null) {
+            return false;
+        }
+        if(baseClassObject.methods.contains(method)) {
+            return true;
+        }
+        return baseClassObject.hasMethodInBaseClass(method);
+    }
+
+    private void appendDefaultInterfaceStubs(StringBuilder b, List<BytecodeMethod> bm) {
+        if(baseInterfacesObject == null) {
+            return;
+        }
+        BytecodeMethod.setAcceptStaticOnEquals(true);
+        for(ByteCodeClass baseInterface : baseInterfacesObject) {
+            appendDefaultInterfaceStubs(b, bm, baseInterface);
+        }
+        BytecodeMethod.setAcceptStaticOnEquals(false);
+    }
+
+    private void appendDefaultInterfaceStubs(StringBuilder b, List<BytecodeMethod> bm, ByteCodeClass baseInterface) {
+        if(baseInterface == null) {
+            return;
+        }
+        if(baseClassObject != null && baseClassObject.doesImplement(baseInterface)) {
+            return;
+        }
+        for(BytecodeMethod m : baseInterface.methods) {
+            if(m.isAbstract() || m.isStatic() || m.isPrivate()) {
+                continue;
+            }
+            if(!bm.contains(m) && !hasMethodInBaseClass(m)) {
+                m.appendSuperCall(b, clsName);
+                bm.add(m);
+            }
+        }
+        if(baseInterface.baseInterfacesObject != null) {
+            for(ByteCodeClass parentInterface : baseInterface.baseInterfacesObject) {
+                appendDefaultInterfaceStubs(b, bm, parentInterface);
+            }
+        }
+    }
 
     private void appendSuperStubHeader(StringBuilder b, List<BytecodeMethod> bm, ByteCodeClass base) {
         BytecodeMethod.setAcceptStaticOnEquals(true);
@@ -1213,6 +1260,40 @@ private void appendSuperStubHeader(StringBuilder b, List<BytecodeMethod> bm, Byt
         }
         BytecodeMethod.setAcceptStaticOnEquals(false);
     }
+
+    private void appendDefaultInterfaceStubHeaders(StringBuilder b, List<BytecodeMethod> bm) {
+        if(baseInterfacesObject == null) {
+            return;
+        }
+        BytecodeMethod.setAcceptStaticOnEquals(true);
+        for(ByteCodeClass baseInterface : baseInterfacesObject) {
+            appendDefaultInterfaceStubHeaders(b, bm, baseInterface);
+        }
+        BytecodeMethod.setAcceptStaticOnEquals(false);
+    }
+
+    private void appendDefaultInterfaceStubHeaders(StringBuilder b, List<BytecodeMethod> bm, ByteCodeClass baseInterface) {
+        if(baseInterface == null) {
+            return;
+        }
+        if(baseClassObject != null && baseClassObject.doesImplement(baseInterface)) {
+            return;
+        }
+        for(BytecodeMethod m : baseInterface.methods) {
+            if(m.isAbstract() || m.isStatic() || m.isPrivate()) {
+                continue;
+            }
+            if(!bm.contains(m) && !hasMethodInBaseClass(m)) {
+                m.appendMethodHeader(b, clsName);
+                bm.add(m);
+            }
+        }
+        if(baseInterface.baseInterfacesObject != null) {
+            for(ByteCodeClass parentInterface : baseInterface.baseInterfacesObject) {
+                appendDefaultInterfaceStubHeaders(b, bm, parentInterface);
+            }
+        }
+    }
 
     private void buildInstanceFieldList(List<ByteCodeField> fieldList) {
         buildInstanceFieldList(fieldList, true);
@@ -1363,10 +1444,13 @@ public String generateCHeader() {
 
         appendMethodsToHeader(b);
 
-        if(baseClassObject != null) {
+        if(!isInterface) {
             // append super stub
             List<BytecodeMethod> bm = new ArrayList<BytecodeMethod>(methods);
-            appendSuperStubHeader(b, bm, baseClassObject);
+            if(baseClassObject != null) {
+                appendSuperStubHeader(b, bm, baseClassObject);
+            }
+            appendDefaultInterfaceStubHeaders(b, bm);
         }
 
         for(BytecodeMethod m : virtualMethodList) {

vm/tests/src/test/java/com/codename1/tools/translator/ParserTest.java

@@ -129,6 +129,11 @@ void translatesDefaultInterfaceMethodImplementations() throws Exception {
         String implCode = impl.generateCCode(classes);
         assertTrue(implCode.contains("&com_example_Greeter_greet___R_java_lang_String"),
                 "Implementing class should point vtable slot to the interface default method implementation");
+        assertTrue(implCode.contains("com_example_GreeterImpl_greet___R_java_lang_String"),
+                "Implementing class should emit a concrete stub for default interface methods");
+        String implHeader = impl.generateCHeader();
+        assertTrue(implHeader.contains("com_example_GreeterImpl_greet___R_java_lang_String"),
+                "Implementing class header should declare the default interface stub");
     }
 
     @Test