美团热修复Robust-源码篇

  上一篇主要分析了Robust的使用方法,这一篇就来总结一下Robust的源码分析。

  我个人倾向于将Robust框架分为两个部分,自动插入代码和动态加载Patch。

一、Robust源码分析

  目前我的分析将Robust动态加载分为两个部分,一部分是插桩后的代码逻辑,一部分是拉取Patch的逻辑。

  我们首先来看插桩后的代码(这里面套用的是官方的代码,可能有些过时了)

  插桩前

public long getIndex() {
    return 100;
}

  插桩后

public static ChangeQuickRedirect changeQuickRedirect;
    public long getIndex() {
        if(changeQuickRedirect != null) {
            //PatchProxy中封装了获取当前className和methodName的逻辑,并在其内部最终调用了changeQuickRedirect的对应函数
            if(PatchProxy.isSupport(new Object[0], this, changeQuickRedirect, false)) {
                return ((Long)PatchProxy.accessDispatch(new Object[0], this, changeQuickRedirect, false)).longValue();
            }
        }
    return 100L;
}

  我们可以看到Robust为我们的类添加了一个静态的ChangeQuickRedirect对象,我们可以看到当ChangeQuickRedirect为空时,证明此时没有补丁,走原逻辑。当它不为空时,我们可以看到它调用了PatchProxy中的isSupport方法和accessDispatch方法。我们具体来看一下PatchProxy中的这两个方法。

  

 1   public static boolean isSupport(Object[] paramsArray, Object current, ChangeQuickRedirect changeQuickRedirect, boolean isStatic, int methodNumber, Class[] paramsClassTypes, Class returnType) {
 2         //Robust补丁优先执行,其他功能靠后
 3         if (changeQuickRedirect == null) {
 4             //不执行补丁,轮询其他监听者
 5             if (registerExtensionList == null || registerExtensionList.isEmpty()) {
 6                 return false;
 7             }
 8             for (RobustExtension robustExtension : registerExtensionList) {
 9                 if (robustExtension.isSupport(new RobustArguments(paramsArray, current, isStatic, methodNumber, paramsClassTypes, returnType))) {
10                     robustExtensionThreadLocal.set(robustExtension);
11                     return true;
12                 }
13             }
14             return false;
15         }
16         String classMethod = getClassMethod(isStatic, methodNumber);
17         if (TextUtils.isEmpty(classMethod)) {
18             return false;
19         }
20         Object[] objects = getObjects(paramsArray, current, isStatic);
21         try {
22             return changeQuickRedirect.isSupport(classMethod, objects);
23         } catch (Throwable t) {
24             return false;
25         }
26     }

  我们可以看到第22行,它调用了changeQuickRedirect.isSupport方法,这个changeQuickRedirect便是我们注入的对象。

  我们接下来再看accessDispatch方法

 1  public static Object accessDispatch(Object[] paramsArray, Object current, ChangeQuickRedirect changeQuickRedirect, boolean isStatic, int methodNumber, Class[] paramsClassTypes, Class returnType) {
 2 
 3         if (changeQuickRedirect == null) {
 4             RobustExtension robustExtension = robustExtensionThreadLocal.get();
 5             robustExtensionThreadLocal.remove();
 6             if (robustExtension != null) {
 7                 notify(robustExtension.describeSelfFunction());
 8                 return robustExtension.accessDispatch(new RobustArguments(paramsArray, current, isStatic, methodNumber, paramsClassTypes, returnType));
 9             }
10             return null;
11         }
12         String classMethod = getClassMethod(isStatic, methodNumber);
13         if (TextUtils.isEmpty(classMethod)) {
14             return null;
15         }
16         notify(Constants.PATCH_EXECUTE);
17         Object[] objects = getObjects(paramsArray, current, isStatic);
18         return changeQuickRedirect.accessDispatch(classMethod, objects);

  可以看到第18行调用了changeQuickRedirect的accseeDispatch方法。

  注入后的代码我们先看到这里,我们接下来看一看,我们拉取Patch的代码

 1   new PatchExecutor(getApplicationContext(), new PatchManpulateImp(), new RobustCallBack() {
 2                     @Override
 3                     public void onPatchListFetched(boolean result, boolean isNet, List patches) {
 4                         Log.e("error-hot", "打印 onPatchListFetched:" + "isNet=" + isNet );
 5                     }
 6                     @Override
 7                     public void onPatchFetched(boolean result, boolean isNet, Patch patch) {
 8                         Log.e("error-hot", "打印 onPatchFetched:" + "result=" + result+"isNet="+isNet + "--->" + "patch=" + patch);
 9                     }
10                     @Override
11                     public void onPatchApplied(boolean result, Patch patch) {
12                         Log.e("error-hot", "打印 onPatchApplied:" + "result=" + result + "--->" + "patch=" + patch);
13                     }
14                     @Override
15                     public void logNotify(String log, String where) {
16                         Log.e("error-hot", "打印 logNotify:" + "log=" + log + "--->" + "where=" + where);
17                     }
18                     @Override
19                     public void exceptionNotify(Throwable throwable, String where) {
20                         Log.e("error-hot", "打印 exceptionNotify:" + "throwable=" + throwable.toString() + "--->" + "where=" + where);
21                     }
22                 }).start();

  进入PatchExecutor类中看一看,我们可以发现它继承了一个线程,那么直接去run方法看一下

 1    @Override
 2     public void run() {
 3         try {
 4             //拉取补丁列表
 5             List patches = fetchPatchList();
 6             //应用补丁列表
 7             applyPatchList(patches);
 8         } catch (Throwable t) {
 9             Log.e("robust", "PatchExecutor run", t);
10             robustCallBack.exceptionNotify(t, "class:PatchExecutor,method:run,line:36");
11         }
12     }

  可以看到run方法中做了两件事,拉取补丁列表和应用补丁列表。

  我们接着进入fetchPatchList方法

1    protected List fetchPatchList() {
2         return patchManipulate.fetchPatchList(context);
3     }

  他返回了patchManipulate的fetchPatchList方法,这个对象便是我们在初始化的时候传进来的。我们进入看一看

 1     @Override
 2     protected List fetchPatchList(Context context) {
 3         Patch patch = new Patch();
 4         patch.setName("test patch");
 5         patch.setLocalPath(Environment.getExternalStorageDirectory().getPath()+
 6                 File.separator+"robust"+File.separator+"patch");
 7         patch.setPatchesInfoImplClassFullName("com.example.tyr.testrobust.PatchesInfoImpl");
 8         List patches = new ArrayList<>();
 9         patches.add(patch);
10         return patches;
11     }

  我们将这个PatchesInfoImpl拉进到列表中,那么这个PatchInfoImpl是在哪里那?我们后面再说。

  接着看applyPatchList方法

  

protected void applyPatchList(List patches) {
        if (null == patches || patches.isEmpty()) {
            return;
        }
        Log.d("robust", " patchManipulate list size is " + patches.size());
        for (Patch p : patches) {
            if (p.isAppliedSuccess()) {
                Log.d("robust", "p.isAppliedSuccess() skip " + p.getLocalPath());
                continue;
            }
            if (patchManipulate.ensurePatchExist(p)) {
                boolean currentPatchResult = false;
                try {
                    currentPatchResult = patch(context, p);
                } catch (Throwable t) {
                    robustCallBack.exceptionNotify(t, "class:PatchExecutor method:applyPatchList line:69");
                }
                if (currentPatchResult) {
                    //设置patch 状态为成功
                    p.setAppliedSuccess(true);
                    //统计PATCH成功率 PATCH成功
                    robustCallBack.onPatchApplied(true, p);

                } else {
                    //统计PATCH成功率 PATCH失败
                    robustCallBack.onPatchApplied(false, p);
                }

                Log.d("robust", "patch LocalPath:" + p.getLocalPath() + ",apply result " + currentPatchResult);

            }
        }
    }

  可以看到for循环patches中的每一个patch并调用patch方法。我们接着进入patch方法。

 1 protected boolean patch(Context context, Patch patch) {
 2         if (!patchManipulate.verifyPatch(context, patch)) {
 3             robustCallBack.logNotify("verifyPatch failure, patch info:" + "id = " + patch.getName() + ",md5 = " + patch.getMd5(), "class:PatchExecutor method:patch line:107");
 4             return false;
 5         }
 6 
 7         DexClassLoader classLoader = new DexClassLoader(patch.getTempPath(), context.getCacheDir().getAbsolutePath(),
 8                 null, PatchExecutor.class.getClassLoader());
 9         patch.delete(patch.getTempPath());
10 
11         Class patchClass, oldClass;
12 
13         Class patchsInfoClass;
14         PatchesInfo patchesInfo = null;
15         try {
16             Log.d("robust", "PatchsInfoImpl name:" + patch.getPatchesInfoImplClassFullName());
17             patchsInfoClass = classLoader.loadClass(patch.getPatchesInfoImplClassFullName());
18             patchesInfo = (PatchesInfo) patchsInfoClass.newInstance();
19             Log.d("robust", "PatchsInfoImpl ok");
20         } catch (Throwable t) {
21             robustCallBack.exceptionNotify(t, "class:PatchExecutor method:patch line:108");
22             Log.e("robust", "PatchsInfoImpl failed,cause of" + t.toString());
23             t.printStackTrace();
24         }
25 
26         if (patchesInfo == null) {
27             robustCallBack.logNotify("patchesInfo is null, patch info:" + "id = " + patch.getName() + ",md5 = " + patch.getMd5(), "class:PatchExecutor method:patch line:114");
28             return false;
29         }
30 
31         //classes need to patch
32         List patchedClasses = patchesInfo.getPatchedClassesInfo();
33         if (null == patchedClasses || patchedClasses.isEmpty()) {
34             robustCallBack.logNotify("patchedClasses is null or empty, patch info:" + "id = " + patch.getName() + ",md5 = " + patch.getMd5(), "class:PatchExecutor method:patch line:122");
35             return false;
36         }
37 
38         for (PatchedClassInfo patchedClassInfo : patchedClasses) {
39             String patchedClassName = patchedClassInfo.patchedClassName;
40             String patchClassName = patchedClassInfo.patchClassName;
41             if (TextUtils.isEmpty(patchedClassName) || TextUtils.isEmpty(patchClassName)) {
42                 robustCallBack.logNotify("patchedClasses or patchClassName is empty, patch info:" + "id = " + patch.getName() + ",md5 = " + patch.getMd5(), "class:PatchExecutor method:patch line:131");
43                 continue;
44             }
45             Log.d("robust", "current path:" + patchedClassName);
46             try {
47                 oldClass = classLoader.loadClass(patchedClassName.trim());
48                 Field[] fields = oldClass.getDeclaredFields();
49                 Log.d("robust", "oldClass :" + oldClass + "     fields " + fields.length);
50                 Field changeQuickRedirectField = null;
51                 for (Field field : fields) {
52                     if (TextUtils.equals(field.getType().getCanonicalName(), ChangeQuickRedirect.class.getCanonicalName()) && TextUtils.equals(field.getDeclaringClass().getCanonicalName(), oldClass.getCanonicalName())) {
53                         changeQuickRedirectField = field;
54                         break;
55                     }
56                 }
57                 if (changeQuickRedirectField == null) {
58                     robustCallBack.logNotify("changeQuickRedirectField  is null, patch info:" + "id = " + patch.getName() + ",md5 = " + patch.getMd5(), "class:PatchExecutor method:patch line:147");
59                     Log.d("robust", "current path:" + patchedClassName + " something wrong !! can  not find:ChangeQuickRedirect in" + patchClassName);
60                     continue;
61                 }
62                 Log.d("robust", "current path:" + patchedClassName + " find:ChangeQuickRedirect " + patchClassName);
63                 try {
64                     patchClass = classLoader.loadClass(patchClassName);
65                     Object patchObject = patchClass.newInstance();
66                     changeQuickRedirectField.setAccessible(true);
67                     changeQuickRedirectField.set(null, patchObject);
68                     Log.d("robust", "changeQuickRedirectField set sucess " + patchClassName);
69                 } catch (Throwable t) {
70                     Log.e("robust", "patch failed! ");
71                     t.printStackTrace();
72                     robustCallBack.exceptionNotify(t, "class:PatchExecutor method:patch line:163");
73                 }
74             } catch (Throwable t) {
75                 Log.e("robust", "patch failed! ");
76                 t.printStackTrace();
77                 robustCallBack.exceptionNotify(t, "class:PatchExecutor method:patch line:169");
78             }
79         }
80         Log.d("robust", "patch finished ");
81         return true;
82     }

  可以看到我们的类加载器在这里加载了我们的patch,我们接下来可以看到classloader加载了我们的PatchInfoImpl类。在这个类中继承了Robust的PatchInfo接口,这里只有一个方法

1 public interface PatchesInfo {
2     List getPatchedClassesInfo();
3 }  

  他拉取了我们需要修改的类的信息。

  这里面的PatchedClassInfo中保存了两个类的信息,一个是我们需要修改的类PatchedClass和修改他的类PatchClass。

  第39,40行Robust拿到了这两个类的名字。

  第48行通过反射获取了我们需要修改的类的所有field

  接下来是一个for循环获取到我们注入代码中的静态ChangeQuickRedirect对象。

  获取到对象后我们看第64行他加载了我们PatchClass的类

  接下来的65,66,67三行,我们可以看到他通过反射将我们PatchedClass即oldClass中的changeQuickRedirect字段赋值为我们的PatchClass。至于这个PatchClass是什么。我们接下来说。

  到目前为止,我们可以看到,插桩后的逻辑已经说完了,不得不说Robust的原理还是比较通俗易懂的。我们接下来回答前面的两个剩余问题,PatchInfoImpl和PatchClass在哪里。我们顺着我们的Patch.jar去寻找。反编译后得到如下列表。

  美团热修复Robust-源码篇_第1张图片

  找到了我们的PatchesInfoImpl,而我们的PatchClass就是RobustActivityPatchControl了

  我们先来看一看PatchesInfoImpl做了什么

 1 import com.meituan.robust.PatchedClassInfo;
 2 import com.meituan.robust.PatchesInfo;
 3 import java.util.ArrayList;
 4 import java.util.List;
 5 
 6 public class PatchesInfoImpl
 7   implements PatchesInfo
 8 {
 9   public List getPatchedClassesInfo()
10   {
11     ArrayList localArrayList = new ArrayList();
12     localArrayList.add(new PatchedClassInfo("com.example.tyr.testrobust.RobustActivity", "com.example.tyr.testrobust.RobustActivityPatchControl"));
13     com.meituan.robust.utils.EnhancedRobustUtils.isThrowable = false;
14     return localArrayList;
15   }
16 }

  可以看到他把我们的patchedClass和patchClass加入了list中,也就是上面返回的信息。

  我们接着看我们注入的这个patchClass中的方法

 1 public class RobustActivityPatchControl
 2   implements ChangeQuickRedirect
 3 {
 4   public static final String MATCH_ALL_PARAMETER = "(\\w*\\.)*\\w*";
 5   private static final Map keyToValueRelation = new WeakHashMap();
 6 
 7   private static Object fixObj(Object paramObject)
 8   {
 9     Object localObject = paramObject;
10     if ((paramObject instanceof Byte))
11       if (((Byte)paramObject).byteValue() == 0)
12         break label32;
13     label32: for (boolean bool = true; ; bool = false)
14     {
15       localObject = new Boolean(bool);
16       return localObject;
17     }
18   }
19 
20   public Object accessDispatch(String paramString, Object[] paramArrayOfObject)
21   {
22     label134: 
23     while (true)
24       try
25       {
26         if (!paramString.split(":")[2].equals("false"))
27           continue;
28         if (keyToValueRelation.get(paramArrayOfObject[(paramArrayOfObject.length - 1)]) != null)
29           continue;
30         RobustActivityPatch localRobustActivityPatch = new RobustActivityPatch(paramArrayOfObject[(paramArrayOfObject.length - 1)]);
31         keyToValueRelation.put(paramArrayOfObject[(paramArrayOfObject.length - 1)], null);
32         break label134;
33         if (!"12".equals(paramString.split(":")[3]))
34           break;
35         localRobustActivityPatch.onCreate((Bundle)paramArrayOfObject[0]);
36         return null;
37         localRobustActivityPatch = (RobustActivityPatch)keyToValueRelation.get(paramArrayOfObject[(paramArrayOfObject.length - 1)]);
38         break label134;
39         localRobustActivityPatch = new RobustActivityPatch(null);
40         continue;
41       }
42       catch (Throwable paramString)
43       {
44         paramString.printStackTrace();
45         return null;
46       }
47     return null;
48   }
49 
50   public Object getRealParameter(Object paramObject)
51   {
52     Object localObject = paramObject;
53     if ((paramObject instanceof RobustActivity))
54       localObject = new RobustActivityPatch(paramObject);
55     return localObject;
56   }
57 
58   public boolean isSupport(String paramString, Object[] paramArrayOfObject)
59   {
60     paramString = paramString.split(":")[3];
61     return ":12:".contains(":" + paramString + ":");
62   }
63 }

  我们可以看到它实现了Robust的ChangeQuickRedirect接口,并实现了他们的两个方法accessDispatch和isSupport的两个方法,也就是PatchProxy中调用的这两个方法。

  先说isSupport方法

  这里的isSupport方法是混淆后的,我们可以看到在PatchProxy类中,他传入了classMethod的名字和这个方法所需要的参数。校验后进行判断。

  在PatchProxy中他传入了的classMethod格式为className:methodName:isStatic:methodNumber。这里只校验了方法的number。这里是在accessDispatch中传入,目测插桩后的代码有所改动。

  继续说accessPatch方法。

  第26行校验了是否为静态方法。将参数数组传给了RobustActivityPatch这个类,并调用了它的onCreat方法,莫名的熟悉感,这个就是我们标注为Modify标签的那个类。

  我们接下来看一看RobustActivityPatch这个类

  

 1 import android.os.Bundle;
 2 import android.support.v7.app.c;
 3 import android.view.View;
 4 import android.widget.TextView;
 5 import com.meituan.robust.utils.EnhancedRobustUtils;
 6 
 7 public class RobustActivityPatch
 8 {
 9   RobustActivity originClass;
10 
11   public RobustActivityPatch(Object paramObject)
12   {
13     this.originClass = ((RobustActivity)paramObject);
14   }
15 
16   public static void staticRobustonCreate(RobustActivityPatch paramRobustActivityPatch, RobustActivity paramRobustActivity, Bundle paramBundle)
17   {
18     RobustActivityPatchRobustAssist.staticRobustonCreate(paramRobustActivityPatch, paramRobustActivity, paramBundle);
19   }
20 
21   public Object[] getRealParameter(Object[] paramArrayOfObject)
22   {
23     if ((paramArrayOfObject == null) || (paramArrayOfObject.length < 1))
24       return paramArrayOfObject;
25     Object[] arrayOfObject = new Object[paramArrayOfObject.length];
26     int i = 0;
27     if (i < paramArrayOfObject.length)
28     {
29       if ((paramArrayOfObject[i] instanceof Object[]))
30         arrayOfObject[i] = getRealParameter((Object[])paramArrayOfObject[i]);
31       while (true)
32       {
33         i += 1;
34         break;
35         if (paramArrayOfObject[i] == this)
36         {
37           arrayOfObject[i] = this.originClass;
38           continue;
39         }
40         arrayOfObject[i] = paramArrayOfObject[i];
41       }
42     }
43     return arrayOfObject;
44   }
45 
46   protected void onCreate(Bundle paramBundle)
47   {
48     staticRobustonCreate(this, this.originClass, paramBundle);
49     EnhancedRobustUtils.invokeReflectMethod("setContentView", ((RobustActivityPatch)this).originClass, getRealParameter(new Object[] { new Integer(2131296284) }), new Class[] { Integer.TYPE }, c.class);
50     paramBundle = (View)EnhancedRobustUtils.invokeReflectMethod("findViewById", ((RobustActivityPatch)this).originClass, getRealParameter(new Object[] { new Integer(2131165307) }), new Class[] { Integer.TYPE }, c.class);
51     if (paramBundle == this);
52     for (paramBundle = ((RobustActivityPatch)paramBundle).originClass; ; paramBundle = (TextView)paramBundle)
53     {
54       String str = (String)EnhancedRobustUtils.invokeReflectMethod("RobustPublicgetString", new RobustActivityInLinePatch(getRealParameter(new Object[] { this })[0]), getRealParameter(new Object[0]), null, null);
55       Object localObject = paramBundle;
56       if (paramBundle == this)
57         localObject = ((RobustActivityPatch)paramBundle).originClass;
58       EnhancedRobustUtils.invokeReflectMethod("setText", localObject, getRealParameter(new Object[] { str }), new Class[] { CharSequence.class }, TextView.class);
59       return;
60     }
61   }
62 }

  看到onCreate方法,第48行,这里我们可以看到他特殊处理了一下我们在RobustActivity的onCreate方法,感觉有点怪怪的,这里似乎是又执行了一边RobustActivity的OnCreate方法,而不是super.onCreate。

  ps:看了看美团官方关于super的解析,似乎是这样的,他通过调用RobustActivity的OnCreate,将class文件中的invokevirtual指令替换为invokesuper指令,从而达到super的效果,这里面还有个问题,如果这样调用会出现这样的问题

Caused by: java.lang.NoSuchMethodError: No super method thisIsSuper()V in class Lcom/meituan/sample/TestSuperClass; or its super classes (declaration of 'com.meituan.sample.TestSuperClass' appears in /data/app/com.meituan.robust.sample-3/base.apk)

  Robust的解决方案是使这个类也继承RobustActivity的父类,我们可以看到RobustActivityPatchRobustAssist类果然继承了一个类,但是由于混淆我们看到的是他继承了一个c的类,猜测它应该就是RobustActivity的父类AppCompatActivity。

  验证一下打印dex文件

  美团热修复Robust-源码篇_第2张图片

  看到invoke-super指令,现在可以确定了

  再看一下RobustActivityPatchRobustAssist的父类,这绝对就是android.support.v7.app.AppcompatActivity了。

  

  然后我们可以看到他执行了setContentView,findViewById这里传入的两串数字便是我们的布局和空间在R类的数字。

  然后我们可以看到它执行到了我们修改代码的地方。

  第54行它调用了RobustPublicgetString方法,又是莫名的熟悉感,,

  进入RobustActivityInLinePatch看一看。

 1 public class RobustActivityInLinePatch
 2 {
 3   RobustActivity originClass;
 4 
 5   public RobustActivityInLinePatch(Object paramObject)
 6   {
 7     this.originClass = ((RobustActivity)paramObject);
 8   }
 9 
10   private String getString()
11   {
12     return "hello robust";
13   }
14 
15   public String RobustPublicgetString()
16   {
17     return getString();
18   }
19 
20   public Object[] getRealParameter(Object[] paramArrayOfObject)
21   {
22     if ((paramArrayOfObject == null) || (paramArrayOfObject.length < 1))
23       return paramArrayOfObject;
24     Object[] arrayOfObject = new Object[paramArrayOfObject.length];
25     int i = 0;
26     if (i < paramArrayOfObject.length)
27     {
28       if ((paramArrayOfObject[i] instanceof Object[]))
29         arrayOfObject[i] = getRealParameter((Object[])paramArrayOfObject[i]);
30       while (true)
31       {
32         i += 1;
33         break;
34         if (paramArrayOfObject[i] == this)
35         {
36           arrayOfObject[i] = this.originClass;
37           continue;
38         }
39         arrayOfObject[i] = paramArrayOfObject[i];
40       }
41     }
42     return arrayOfObject;
43   }
44 }

  可以看到我们传入的getString方法出现在了这里。

二、总结

  到目前为止,Robust的逻辑算是走通了。

  目前为止,我认为Robust的核心应该算是它自动插桩的那一部分,目前暂时不涉及了,下一篇将会了解一下热修复背后的动态加载。

参考资料:

  Android中热修复框架Robust原理解析+并将框架代码从"闭源"变成"开源"(上篇)

  Android热更新方案Robust

 

转载于:https://www.cnblogs.com/yrstudy/p/8977315.html

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