Examples with ClassVisitor org.simpleflatmapper.ow2asm.ClassVisitor used on opensource projects

Example 1 with ClassVisitor

use of org.simpleflatmapper.ow2asm.ClassVisitor in project SimpleFlatMapper by arnaudroger.

the class AsmInstantiatorDefinitionFactory method extractDefinitions.

public static List<InstantiatorDefinition> extractDefinitions(final Type target) throws IOException {
    final List<InstantiatorDefinition> constructors = new ArrayList<InstantiatorDefinition>();
    final Class<?> targetClass = TypeHelper.toClass(target);
    ClassLoader cl = targetClass.getClassLoader();
    if (cl == null) {
        cl = ClassLoader.getSystemClassLoader();
    }
    final String fileName = targetClass.getName().replace('.', '/') + ".class";
    final InputStream is = cl.getResourceAsStream(fileName);
    try {
        if (is == null) {
            throw new IOException("Cannot find file " + fileName + " in " + cl);
        }
        ClassReader classReader = new ClassReader(is);
        classReader.accept(new ClassVisitor(Opcodes.ASM5) {

            List<String> genericTypeNames;

            @Override
            public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
                if (signature != null) {
                    genericTypeNames = AsmUtils.extractGenericTypeNames(signature);
                } else {
                    genericTypeNames = Collections.emptyList();
                }
                super.visit(version, access, name, signature, superName, interfaces);
            }

            @Override
            public MethodVisitor visitMethod(int access, final String methodName, String desc, String signature, String[] exceptions) {
                final boolean isConstructor = "<init>".equals(methodName);
                if ((Opcodes.ACC_PUBLIC & access) == Opcodes.ACC_PUBLIC && (isConstructor || ((Opcodes.ACC_STATIC & access) == Opcodes.ACC_STATIC && !desc.endsWith("V")))) {
                    final List<String> descTypes = AsmUtils.extractTypeNamesFromSignature(desc);
                    final List<String> genericTypes;
                    final List<String> names = new ArrayList<String>();
                    if (signature != null) {
                        genericTypes = AsmUtils.extractTypeNamesFromSignature(signature);
                    } else {
                        genericTypes = descTypes;
                    }
                    if (!isConstructor) {
                        if (descTypes.size() > 0) {
                            try {
                                final Type genericType = AsmUtils.toGenericType(descTypes.get(descTypes.size() - 1), genericTypeNames, target);
                                if (!targetClass.isAssignableFrom(TypeHelper.toClass(genericType))) {
                                    return null;
                                }
                            } catch (ClassNotFoundException e) {
                                return null;
                            }
                        } else
                            return null;
                    }
                    return new MethodVisitor(Opcodes.ASM5) {

                        Label firstLabel;

                        Label lastLabel;

                        @Override
                        public void visitLabel(Label label) {
                            if (firstLabel == null) {
                                firstLabel = label;
                            }
                            lastLabel = label;
                        }

                        @Override
                        public void visitLocalVariable(String name, String desc, String signature, Label start, Label end, int index) {
                            if (start.equals(firstLabel) && end.equals(lastLabel) && !"this".equals(name)) {
                                names.add(name);
                            }
                        }

                        @Override
                        public void visitEnd() {
                            try {
                                final List<Parameter> parameters = new ArrayList<Parameter>();
                                int l = descTypes.size() - (isConstructor ? 0 : 1);
                                for (int i = 0; i < l; i++) {
                                    String name = "arg" + i;
                                    if (i < names.size()) {
                                        name = names.get(i);
                                    }
                                    parameters.add(createParameter(i, name, descTypes.get(i), genericTypes.get(i)));
                                }
                                final Member executable;
                                if (isConstructor) {
                                    executable = targetClass.getDeclaredConstructor(toTypeArray(parameters));
                                } else {
                                    executable = targetClass.getDeclaredMethod(methodName, toTypeArray(parameters));
                                }
                                constructors.add(new ExecutableInstantiatorDefinition(executable, parameters.toArray(new Parameter[0])));
                            } catch (Exception e) {
                                ErrorHelper.rethrow(e);
                            }
                        }

                        private Class<?>[] toTypeArray(List<Parameter> parameters) {
                            Class<?>[] types = new Class<?>[parameters.size()];
                            for (int i = 0; i < types.length; i++) {
                                types[i] = parameters.get(i).getType();
                            }
                            return types;
                        }

                        private Parameter createParameter(int index, String name, String desc, String signature) {
                            try {
                                Type basicType = AsmUtils.toGenericType(desc, genericTypeNames, target);
                                Type genericType = basicType;
                                if (signature != null) {
                                    Type type = AsmUtils.toGenericType(signature, genericTypeNames, target);
                                    if (type != null) {
                                        genericType = type;
                                    }
                                }
                                return new Parameter(index, name, TypeHelper.toClass(basicType), genericType);
                            } catch (ClassNotFoundException e) {
                                throw new Error("Unexpected error " + e, e);
                            }
                        }
                    };
                } else {
                    return null;
                }
            }
        }, 0);
    } finally {
        if (is != null) {
            try {
                is.close();
            } catch (Exception e) {
            }
        }
    }
    return constructors;
}