Examples with ExprEditor org.hotswap.agent.javassist.expr.ExprEditor used on opensource projects

Example 6 with ExprEditor

use of org.hotswap.agent.javassist.expr.ExprEditor in project HotswapAgent by HotswapProjects.

the class ClassInitPlugin method patch.

@OnClassLoadEvent(classNameRegexp = ".*", events = LoadEvent.REDEFINE)
public static void patch(final CtClass ctClass, final ClassLoader classLoader, final Class<?> originalClass) throws IOException, CannotCompileException, NotFoundException {
    if (isSyntheticClass(originalClass)) {
        return;
    }
    final String className = ctClass.getName();
    try {
        CtMethod origMethod = ctClass.getDeclaredMethod(HOTSWAP_AGENT_CLINIT_METHOD);
        ctClass.removeMethod(origMethod);
    } catch (org.hotswap.agent.javassist.NotFoundException ex) {
    // swallow
    }
    CtConstructor clinit = ctClass.getClassInitializer();
    if (clinit != null) {
        LOGGER.debug("Adding __ha_clinit to class: {}", className);
        CtConstructor haClinit = new CtConstructor(clinit, ctClass, null);
        haClinit.getMethodInfo().setName(HOTSWAP_AGENT_CLINIT_METHOD);
        haClinit.setModifiers(Modifier.PUBLIC | Modifier.STATIC);
        ctClass.addConstructor(haClinit);
        final boolean[] reinitializeStatics = new boolean[] { false };
        haClinit.instrument(new ExprEditor() {

            public void edit(FieldAccess f) throws CannotCompileException {
                try {
                    if (f.isStatic() && f.isWriter()) {
                        Field originalField = null;
                        try {
                            originalField = originalClass.getDeclaredField(f.getFieldName());
                        } catch (NoSuchFieldException e) {
                            LOGGER.debug("New field will be initialized {}", f.getFieldName());
                            reinitializeStatics[0] = true;
                        }
                        if (originalField != null) {
                            // ENUM$VALUES is last in enumeration
                            if (originalClass.isEnum() && "ENUM$VALUES".equals(f.getFieldName())) {
                                if (reinitializeStatics[0]) {
                                    LOGGER.debug("New field will be initialized {}", f.getFieldName());
                                } else {
                                    reinitializeStatics[0] = checkOldEnumValues(ctClass, originalClass);
                                }
                            } else {
                                LOGGER.debug("Skipping old field {}", f.getFieldName());
                                f.replace("{}");
                            }
                        }
                    }
                } catch (Exception e) {
                    LOGGER.error("Patching __ha_clinit method failed.", e);
                }
            }
        });
        if (reinitializeStatics[0]) {
            PluginManager.getInstance().getScheduler().scheduleCommand(new Command() {

                @Override
                public void executeCommand() {
                    try {
                        Class<?> clazz = classLoader.loadClass(className);
                        Method m = clazz.getDeclaredMethod(HOTSWAP_AGENT_CLINIT_METHOD, new Class[] {});
                        if (m != null) {
                            m.invoke(null, new Object[] {});
                        }
                    } catch (Exception e) {
                        LOGGER.error("Error initializing redefined class {}", e, className);
                    } finally {
                        reloadFlag = false;
                    }
                }
            }, // Hack : init should be done after dependant class redefinition. Since the class can
            150);
        // be proxied by syntetic proxy, the class init must be scheduled after proxy redefinition.
        // Currently proxy redefinition (in ProxyPlugin) is scheduled with 100ms delay, therefore
        // the class init must be scheduled after it.
        } else {
            reloadFlag = false;
        }
    }
}