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基本使用
//创建一个PatchManager实例
patchManager = new PatchManager(context);
//初始化
patchManager.init(appversion);//current version
//加载补丁
patchManager.loadPatch();
// 手动加载补丁
//patchManager.addPatch(path);//path of the patch file that was downloaded
源码分析
//PatchManager构造方法 主要是实例化一些对象和创建爱你一些表
public PatchManager(Context context) {
mContext = context;
mAndFixManager = new AndFixManager(mContext);
mPatchDir = new File(mContext.getFilesDir(), DIR);
mPatchs = new ConcurrentSkipListSet<Patch>();
mLoaders = new ConcurrentHashMap<String, ClassLoader>();
}
//初始化方法 主要是查看版本，清除旧的补丁文件 ，把需要的补丁文件封装成patch对象放到一个集合ConcurrentSkipListSet
/**
* initialize
*
* @param appVersion
* App version
*/
public void init(String appVersion) {
if (!mPatchDir.exists() && !mPatchDir.mkdirs()) {// make directory fail
Log.e(TAG, "patch dir create error.");
return;
} else if (!mPatchDir.isDirectory()) {// not directory
mPatchDir.delete();
return;
}
SharedPreferences sp = mContext.getSharedPreferences(SP_NAME,
Context.MODE_PRIVATE);
String ver = sp.getString(SP_VERSION, null);
if (ver == null || !ver.equalsIgnoreCase(appVersion)) {
cleanPatch();
sp.edit().putString(SP_VERSION, appVersion).commit();
} else {
initPatchs();
}
}
private void initPatchs() {
File[] files = mPatchDir.listFiles();
for (File file : files) {
addPatch(file);
}
}
/**
* add patch file
*
* @param file
* @return patch
*/
private Patch addPatch(File file) {
Patch patch = null;
if (file.getName().endsWith(SUFFIX)) {
try {
patch = new Patch(file);
mPatchs.add(patch);
} catch (IOException e) {
Log.e(TAG, "addPatch", e);
}
}
return patch;
}
** PatchManager#loadPatch 方法 **
//当应用启动时候加载补丁
public void loadPatch() {
mLoaders.put("*", mContext.getClassLoader());// wildcard
Set<String> patchNames;
List<String> classes;
for (Patch patch : mPatchs) {
patchNames = patch.getPatchNames();
for (String patchName : patchNames) {
classes = patch.getClasses(patchName);
//最终调用AndFixManager里面的fix方法修复
mAndFixManager.fix(patch.getFile(), mContext.getClassLoader(),
classes);
}
}
}
** AndFixManager#fix 方法 **
public synchronized void fix(String patchPath) {
fix(new File(patchPath), mContext.getClassLoader(), null);
}
//真正的fix方法
public synchronized void fix(File file, ClassLoader classLoader,
List<String> classes) {
if (!mSupport) {
return;
}
//安全验证
if (!mSecurityChecker.verifyApk(file)) {// security check fail
return;
}
try {
File optfile = new File(mOptDir, file.getName());
boolean saveFingerprint = true;
if (optfile.exists()) {
// need to verify fingerprint when the optimize file exist,
// prevent someone attack on jailbreak device with
// Vulnerability-Parasyte.
// btw:exaggerated android Vulnerability-Parasyte
// http://secauo.com/Exaggerated-Android-Vulnerability-Parasyte.html
if (mSecurityChecker.verifyOpt(optfile)) {
saveFingerprint = false;
} else if (!optfile.delete()) {
return;
}
}
//DexFile 加载dex
final DexFile dexFile = DexFile.loadDex(file.getAbsolutePath(),
optfile.getAbsolutePath(), Context.MODE_PRIVATE);
if (saveFingerprint) {
mSecurityChecker.saveOptSig(optfile);
}
ClassLoader patchClassLoader = new ClassLoader(classLoader) {
@Override
protected Class<?> findClass(String className)
throws ClassNotFoundException {
Class<?> clazz = dexFile.loadClass(className, this);
if (clazz == null
&& className.startsWith("com.alipay.euler.andfix")) {
return Class.forName(className);// annotation’s class
// not found
}
if (clazz == null) {
throw new ClassNotFoundException(className);
}
return clazz;
}
};
Enumeration<String> entrys = dexFile.entries();
Class<?> clazz = null;
while (entrys.hasMoreElements()) {
String entry = entrys.nextElement();
//通过classloader找到要修复的类
if (classes != null && !classes.contains(entry)) {
continue;// skip, not need fix
}
clazz = dexFile.loadClass(entry, patchClassLoader);
//找到对应的类实例
if (clazz != null) {
//调用fixclass进行修复
fixClass(clazz, classLoader);
}
}
} catch (IOException e) {
Log.e(TAG, "pacth", e);
}
}
** AndFixManager#fixClass 方法 **
private void fixClass(Class<?> clazz, ClassLoader classLoader) {
Method[] methods = clazz.getDeclaredMethods();
MethodReplace methodReplace;
String clz;
String meth;
for (Method method : methods) {
//拿到带注解的方法，即找到要修复方法
methodReplace = method.getAnnotation(MethodReplace.class);
if (methodReplace == null)
continue;
clz = methodReplace.clazz();
meth = methodReplace.method();
if (!isEmpty(clz) && !isEmpty(meth)) {
//进行方法的替换
replaceMethod(classLoader, clz, meth, method);
}
}
}
** AndFixManager#replaceMethod 方法 **
//主要是通过本地方法进行方法指针的替换
private void replaceMethod(ClassLoader classLoader, String clz,
String meth, Method method) {
try {
String key = clz + "@" + classLoader.toString();
Class<?> clazz = mFixedClass.get(key);
if (clazz == null) {// class not load
Class<?> clzz = classLoader.loadClass(clz);
// initialize target class
clazz = AndFix.initTargetClass(clzz);
}
if (clazz != null) {// initialize class OK
mFixedClass.put(key, clazz);
Method src = clazz.getDeclaredMethod(meth,
method.getParameterTypes());
AndFix.addReplaceMethod(src, method);
}
} catch (Exception e) {
Log.e(TAG, "replaceMethod", e);
}
}
** AndFixManager#replaceMethod 方法 **
private static native void replaceMethod(Method dest, Method src);
/**
* replace method's body
*
* @param src
* source method
* @param dest
* target method
*
*/
public static void addReplaceMethod(Method src, Method dest) {
try {
//通过调用本地方法replaceMethod实现
replaceMethod(src, dest);
initFields(dest.getDeclaringClass());
} catch (Throwable e) {
Log.e(TAG, "addReplaceMethod", e);
}
}
** AndFix.c replaceMethod函数 **
static void replaceMethod(JNIEnv* env, jclass clazz, jobject src,
jobject dest) {
//判断是否是ART虚拟机
if (isArt) {
art_replaceMethod(env, src, dest);
} else {
dalvik_replaceMethod(env, src, dest);
}
}
// 这里我们找一个虚拟机环境的函数分析即可
extern void __attribute__ ((visibility ("hidden"))) dalvik_replaceMethod(
JNIEnv* env, jobject src, jobject dest) {
jobject clazz = env->CallObjectMethod(dest, jClassMethod);
ClassObject* clz = (ClassObject*) dvmDecodeIndirectRef_fnPtr(
dvmThreadSelf_fnPtr(), clazz);
clz->status = CLASS_INITIALIZED;
Method* meth = (Method*) env->FromReflectedMethod(src);
Method* target = (Method*) env->FromReflectedMethod(dest);
LOGD("dalvikMethod: %s", meth->name);
//替换目标方法的各种属性，简言之指针的替换
// meth->clazz = target->clazz;
meth->accessFlags |= ACC_PUBLIC;
meth->methodIndex = target->methodIndex;
meth->jniArgInfo = target->jniArgInfo;
meth->registersSize = target->registersSize;
meth->outsSize = target->outsSize;
meth->insSize = target->insSize;
meth->prototype = target->prototype;
meth->insns = target->insns;
meth->nativeFunc = target->nativeFunc;
}