Allow to exclude certain classes, fields and methods from compilation

core/src/main/java/org/teavm/parsing/ClasspathResourceMapper.java

@@ -24,7 +24,10 @@ import java.util.*;
 import java.util.function.Function;
 import org.teavm.common.CachedFunction;
 import org.teavm.model.ClassHolder;
+import org.teavm.model.FieldHolder;
+import org.teavm.model.MethodHolder;
 import org.teavm.model.ReferenceCache;
+import org.teavm.vm.spi.ElementFilter;
 
 public class ClasspathResourceMapper implements Function<String, ClassHolder>, ClassDateProvider {
     private static final String PACKAGE_PREFIX = "packagePrefix.";
@@ -35,6 +38,7 @@ public class ClasspathResourceMapper implements Function<String, ClassHolder>, C
     private ClassLoader classLoader;
     private Map<String, ModificationDate> modificationDates = new HashMap<>();
     private ReferenceCache referenceCache;
+    private List<ElementFilter> elementFilters = new ArrayList<>();
 
     private static class Transformation {
         String packageName;
@@ -63,6 +67,11 @@ public class ClasspathResourceMapper implements Function<String, ClassHolder>, C
             throw new RuntimeException("Error reading resources", e);
         }
         renamer = new ClassRefsRenamer(referenceCache, new CachedFunction<>(classNameMapper));
+
+        for (ElementFilter elementFilter : ServiceLoader.load(ElementFilter.class)) {
+            elementFilters.add(elementFilter);
+        }
+
         this.classLoader = classLoader;
     }
 
@@ -104,6 +113,38 @@ public class ClasspathResourceMapper implements Function<String, ClassHolder>, C
 
     @Override
     public ClassHolder apply(String name) {
+        for (ElementFilter filter : elementFilters) {
+            if (!filter.acceptClass(name)) {
+                return null;
+            }
+        }
+
+        ClassHolder cls = find(name);
+
+        if (cls != null) {
+            for (MethodHolder method : cls.getMethods().toArray(new MethodHolder[0])) {
+                for (ElementFilter filter : elementFilters) {
+                    if (!filter.acceptMethod(method.getReference())) {
+                        cls.removeMethod(method);
+                        break;
+                    }
+                }
+            }
+
+            for (FieldHolder field : cls.getFields().toArray(new FieldHolder[0])) {
+                for (ElementFilter filter : elementFilters) {
+                    if (!filter.acceptField(field.getReference())) {
+                        cls.removeField(field);
+                        break;
+                    }
+                }
+            }
+        }
+
+        return cls;
+    }
+
+    private ClassHolder find(String name) {
         for (Transformation transformation : transformations) {
             if (name.startsWith(transformation.packageName)) {
                 int index = name.lastIndexOf('.');

core/src/main/java/org/teavm/vm/spi/ElementFilter.java

@@ -0,0 +1,27 @@
+/*
+ *  Copyright 2019 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.vm.spi;
+
+import org.teavm.model.FieldReference;
+import org.teavm.model.MethodReference;
+
+public interface ElementFilter {
+    boolean acceptClass(String className);
+
+    boolean acceptMethod(MethodReference method);
+
+    boolean acceptField(FieldReference field);
+}