本系列 Tinker 源码解析基于 Tinker v1.9.12

前一篇讲到了利用反射执行的是 TinkerLoader.tryLoad 方法

tryLoad

    @Override
    public Intent tryLoad(TinkerApplication app) {
        Intent resultIntent = new Intent();
    
        long begin = SystemClock.elapsedRealtime();
        tryLoadPatchFilesInternal(app, resultIntent);
        long cost = SystemClock.elapsedRealtime() - begin;
        ShareIntentUtil.setIntentPatchCostTime(resultIntent, cost);
        return resultIntent;
    }

加载的流程主要在 tryLoadPatchFilesInternal 里面。tryLoadPatchFilesInternal 方法很长，我们需要分段来看。

tryLoadPatchFilesInternal

一开始是各种校验

检查 tinker 是否开启

    final int tinkerFlag = app.getTinkerFlags();
    // 检查 tinker 是否开启
    if (!ShareTinkerInternals.isTinkerEnabled(tinkerFlag)) {
        Log.w(TAG, "tryLoadPatchFiles: tinker is disable, just return");
        ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_DISABLE);
        return;
    }

检查当前的进程

    // 检查当前的进程，确保不是 :patch 进程
    if (ShareTinkerInternals.isInPatchProcess(app)) {
        Log.w(TAG, "tryLoadPatchFiles: we don't load patch with :patch process itself, just return");
        ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_DISABLE);
        return;
    }

获取 tinker 目录，检查目录是否存在

    // tinker 获取 tinker 目录，/data/data/tinker.sample.android/tinker
    File patchDirectoryFile = SharePatchFileUtil.getPatchDirectory(app);
    if (patchDirectoryFile == null) {
        Log.w(TAG, "tryLoadPatchFiles:getPatchDirectory == null");
        //treat as not exist
        ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_PATCH_DIRECTORY_NOT_EXIST);
        return;
    }
    String patchDirectoryPath = patchDirectoryFile.getAbsolutePath();
    // 检查 tinker 目录是否存在
    //check patch directory whether exist
    if (!patchDirectoryFile.exists()) {
        Log.w(TAG, "tryLoadPatchFiles:patch dir not exist:" + patchDirectoryPath);
        ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_PATCH_DIRECTORY_NOT_EXIST);
        return;
    }

检查 patch.info 文件是否存在, patch.info 是补丁信息文件，里面记录着新旧两个补丁版本的 md5 值

    // 文件目录 /data/data/tinker.sample.android/tinker/patch.info
    File patchInfoFile = SharePatchFileUtil.getPatchInfoFile(patchDirectoryPath);
    
    // 检查 patch.info 补丁信息文件是否存在
    //check patch info file whether exist
    if (!patchInfoFile.exists()) {
        Log.w(TAG, "tryLoadPatchFiles:patch info not exist:" + patchInfoFile.getAbsolutePath());
        ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_PATCH_INFO_NOT_EXIST);
        return;
    }

读取 patch.info 文件，并包装成一个 SharePatchInfo ，并检查 patchInfo 是否为空 (先加锁 file lock 再解锁)

    //old = 641e634c5b8f1649c75caf73794acbdf
    //new = 2c150d8560334966952678930ba67fa8
    // tinker/info.lock
    File patchInfoLockFile = SharePatchFileUtil.getPatchInfoLockFile(patchDirectoryPath);
    
    // 检查 patch info 文件中的补丁版本信息
    patchInfo = SharePatchInfo.readAndCheckPropertyWithLock(patchInfoFile, patchInfoLockFile);
    if (patchInfo == null) {
        ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_PATCH_INFO_CORRUPTED);
        return;
    }

检查读取出来的 patchInfo 补丁版本信息

    String oldVersion = patchInfo.oldVersion;
    String newVersion = patchInfo.newVersion;
    String oatDex = patchInfo.oatDir;
    
    if (oldVersion == null || newVersion == null || oatDex == null) {
        //it is nice to clean patch
        Log.w(TAG, "tryLoadPatchFiles:onPatchInfoCorrupted");
        ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_PATCH_INFO_CORRUPTED);
        return;
    }

如果发现 patchInfo 中的 isRemoveNewVersion 为 true 并且在主进程中运行的话，就代表需要清除补丁了

    boolean mainProcess = ShareTinkerInternals.isInMainProcess(app);
    boolean isRemoveNewVersion = patchInfo.isRemoveNewVersion;

    // So far new version is not loaded in main process and other processes.
    // We can remove new version directory safely.
    if (mainProcess && isRemoveNewVersion) {
        Log.w(TAG, "found clean patch mark and we are in main process, delete patch file now.");
        // 获取新的补丁文件夹，例如 patch-2c150d85
        String patchName = SharePatchFileUtil.getPatchVersionDirectory(newVersion);
        if (patchName != null) {
             // 删除新的补丁文件夹   
            String patchVersionDirFullPath = patchDirectoryPath + "/" + patchName;
            SharePatchFileUtil.deleteDir(patchVersionDirFullPath);
            // 如果旧版本和新版本一致，就把 oldVersion 和 newVersion 设置为空来清除补丁
            if (oldVersion.equals(newVersion)) {
                // !oldVersion.equals(newVersion) means new patch is applied, just fall back to old one in that case.
                // Or we will set oldVersion and newVersion to empty string to clean patch.
                oldVersion = "";
            }
            // 如果 !oldVersion.equals(newVersion) 意味着新补丁已经应用了，需要回退到原来的旧版本
            newVersion = oldVersion;
            patchInfo.oldVersion = oldVersion;
            patchInfo.newVersion = newVersion;
            // 把数据重新写入 patchInfo 文件中
            SharePatchInfo.rewritePatchInfoFileWithLock(patchInfoFile, patchInfo, patchInfoLockFile);
            // 杀掉主进程以外的所有进程
            ShareTinkerInternals.killProcessExceptMain(app);
        }
    }
    
    resultIntent.putExtra(ShareIntentUtil.INTENT_PATCH_OLD_VERSION, oldVersion);
    resultIntent.putExtra(ShareIntentUtil.INTENT_PATCH_NEW_VERSION, newVersion);

根据版本变化和是否是主进程的条件决定是否允许加载最新的补丁

    boolean versionChanged = !(oldVersion.equals(newVersion));
    boolean oatModeChanged = oatDex.equals(ShareConstants.CHANING_DEX_OPTIMIZE_PATH);
    oatDex = ShareTinkerInternals.getCurrentOatMode(app, oatDex);
    resultIntent.putExtra(ShareIntentUtil.INTENT_PATCH_OAT_DIR, oatDex);
    
    String version = oldVersion;
    
    // 根据版本变化和是否是主进程的条件决定是否允许加载最新的补丁
    if (versionChanged && mainProcess) {
        version = newVersion;
    }
    if (ShareTinkerInternals.isNullOrNil(version)) {
        Log.w(TAG, "tryLoadPatchFiles:version is blank, wait main process to restart");
        ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_PATCH_INFO_BLANK);
        return;
    }

检查当前新版本补丁文件夹是否存在

    //patch-641e634c
    String patchName = SharePatchFileUtil.getPatchVersionDirectory(version);
    if (patchName == null) {
        Log.w(TAG, "tryLoadPatchFiles:patchName is null");
        //we may delete patch info file
        ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_PATCH_VERSION_DIRECTORY_NOT_EXIST);
        return;
    }
    //tinker/patch.info/patch-641e634c
    String patchVersionDirectory = patchDirectoryPath + "/" + patchName;
    
    File patchVersionDirectoryFile = new File(patchVersionDirectory);
    
    if (!patchVersionDirectoryFile.exists()) {
        Log.w(TAG, "tryLoadPatchFiles:onPatchVersionDirectoryNotFound");
        //we may delete patch info file
        ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_PATCH_VERSION_DIRECTORY_NOT_EXIST);
        return;
    }

检查补丁文件是否存在并且可读

    //tinker/patch.info/patch-641e634c/patch-641e634c.apk
    final String patchVersionFileRelPath = SharePatchFileUtil.getPatchVersionFile(version);
    File patchVersionFile = (patchVersionFileRelPath != null ? new File(patchVersionDirectoryFile.getAbsolutePath(), patchVersionFileRelPath) : null);
    
    if (!SharePatchFileUtil.isLegalFile(patchVersionFile)) {
        Log.w(TAG, "tryLoadPatchFiles:onPatchVersionFileNotFound");
        //we may delete patch info file
        ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_PATCH_VERSION_FILE_NOT_EXIST);
        return;
    }

检查补丁文件签名以及补丁文件中的 tinker id 和基准包的 tinker id 是否一致。

注意，这里补丁文件的 tinker id 是当前补丁基准包的 tinker id ，也就是有 bug 的基准包 tinker id 。另外一个 new tinker id 是补丁加载完成后的 tinker id ，就是 bug 修复后的 tinker id 。

    ShareSecurityCheck securityCheck = new ShareSecurityCheck(app);
    // 1. 检查补丁包 apk 的签名
    // 2. 检查基准包的 tinker id 与补丁包中是否一致
    // 3. 检查 tinker 设置与补丁包中的类型是否符合
    int returnCode = ShareTinkerInternals.checkTinkerPackage(app, tinkerFlag, patchVersionFile, securityCheck);
    if (returnCode != ShareConstants.ERROR_PACKAGE_CHECK_OK) {
        Log.w(TAG, "tryLoadPatchFiles:checkTinkerPackage");
        resultIntent.putExtra(ShareIntentUtil.INTENT_PATCH_PACKAGE_PATCH_CHECK, returnCode);
        ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_PATCH_PACKAGE_CHECK_FAIL);
        return;
    }

    resultIntent.putExtra(ShareIntentUtil.INTENT_PATCH_PACKAGE_CONFIG, securityCheck.getPackagePropertiesIfPresent());

下面是 checkTinkerPackage 方法的具体代码

    public static int checkTinkerPackage(Context context, int tinkerFlag, File patchFile, ShareSecurityCheck securityCheck) {
        // 检查补丁文件签名和 tinker id 是否一致
        // 这里为了快速校验,就只检验补丁包内部以meta.txt结尾的文件的签名，而其他的文件的合法性则通过meta.txt文件内部记录的补丁文件Md5值来校验
        int returnCode = checkSignatureAndTinkerID(context, patchFile, securityCheck);
        if (returnCode == ShareConstants.ERROR_PACKAGE_CHECK_OK) {
            // 检查配置的 tinker flag 和 meta.txt 是否匹配
            // 如果不匹配的话，中断接下来的流程
            returnCode = checkPackageAndTinkerFlag(securityCheck, tinkerFlag);
        }
        return returnCode;
    }

根据不同的情况,最多有四个文件是以meta.txt结尾的:

• package_meta.txt 补丁包的基本信息
• dex_meta.txt dex补丁的信息
• so_meta.txt so补丁的信息
• res_meta.txt 资源补丁的信息

如果开启了支持 dex 热修复，检查 dex_meta.txt 文件中记录的dex文件信息对应的dex文件是否存在

    final boolean isEnabledForDex = ShareTinkerInternals.isTinkerEnabledForDex(tinkerFlag);
    
    if (isEnabledForDex) {
        //tinker/patch.info/patch-641e634c/dex
        // 检查下发的meta文件中记录的dex信息中对应的dex文件是否存在
        boolean dexCheck = TinkerDexLoader.checkComplete(patchVersionDirectory, securityCheck, oatDex, resultIntent);
        if (!dexCheck) {
            //file not found, do not load patch
            Log.w(TAG, "tryLoadPatchFiles:dex check fail");
            return;
        }
    }

如果开启了支持 so 热修复，检查 so_meta.txt 文件中记录的so文件信息对应的so文件是否存在

    final boolean isEnabledForNativeLib = ShareTinkerInternals.isTinkerEnabledForNativeLib(tinkerFlag);
    
    if (isEnabledForNativeLib) {
        //tinker/patch.info/patch-641e634c/lib
        boolean libCheck = TinkerSoLoader.checkComplete(patchVersionDirectory, securityCheck, resultIntent);
        if (!libCheck) {
            //file not found, do not load patch
            Log.w(TAG, "tryLoadPatchFiles:native lib check fail");
            return;
        }
    }

如果开启了支持 res 热修复，检查 res_meta.txt 文件中记录的res文件信息对应的res文件是否存在

    //check resource
    final boolean isEnabledForResource = ShareTinkerInternals.isTinkerEnabledForResource(tinkerFlag);
    Log.w(TAG, "tryLoadPatchFiles:isEnabledForResource:" + isEnabledForResource);
    if (isEnabledForResource) {
        boolean resourceCheck = TinkerResourceLoader.checkComplete(app, patchVersionDirectory, securityCheck, resultIntent);
        if (!resourceCheck) {
            //file not found, do not load patch
            Log.w(TAG, "tryLoadPatchFiles:resource check fail");
            return;
        }
    }

符合条件的话就更新版本信息,并将最新的patch info更新入文件.在v1.7.5的版本开始有了isSystemOTA判断,

只要用户是ART环境并且做了OTA升级，则在加载dex补丁的时候就会先把最近一次的补丁全部DexFile.loadDex一遍重新生成odex，再加载dex补丁。否则会报错

    //only work for art platform oat，because of interpret, refuse 4.4 art oat
    //android o use quicken default, we don't need to use interpret mode
    boolean isSystemOTA = ShareTinkerInternals.isVmArt()
        && ShareTinkerInternals.isSystemOTA(patchInfo.fingerPrint)
        && Build.VERSION.SDK_INT >= 21 && !ShareTinkerInternals.isAfterAndroidO();
    
    resultIntent.putExtra(ShareIntentUtil.INTENT_PATCH_SYSTEM_OTA, isSystemOTA);
    
    //we should first try rewrite patch info file, if there is a error, we can't load jar
    // 把patch.info的旧版本的值更新为新版本的值，写入 patch.info 中
    if (mainProcess && (versionChanged || oatModeChanged)) {
        patchInfo.oldVersion = version;
        patchInfo.oatDir = oatDex;
    
        //update old version to new
        if (!SharePatchInfo.rewritePatchInfoFileWithLock(patchInfoFile, patchInfo, patchInfoLockFile)) {
            ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_PATCH_REWRITE_PATCH_INFO_FAIL);
            Log.w(TAG, "tryLoadPatchFiles:onReWritePatchInfoCorrupted");
            return;
        }
    
        Log.i(TAG, "tryLoadPatchFiles:success to rewrite patch info, kill other process.");
        ShareTinkerInternals.killProcessExceptMain(app);
    
        if (oatModeChanged) {
            // delete interpret odex
            // for android o, directory change. Fortunately, we don't need to support android o interpret mode any more
            Log.i(TAG, "tryLoadPatchFiles:oatModeChanged, try to delete interpret optimize files");
            SharePatchFileUtil.deleteDir(patchVersionDirectory + "/" + ShareConstants.INTERPRET_DEX_OPTIMIZE_PATH);
        }
    }

加载补丁的安全次数最多三次

    if (!checkSafeModeCount(app)) {
        resultIntent.putExtra(ShareIntentUtil.INTENT_PATCH_EXCEPTION, new TinkerRuntimeException("checkSafeModeCount fail"));
        ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_PATCH_UNCAUGHT_EXCEPTION);
        Log.w(TAG, "tryLoadPatchFiles:checkSafeModeCount fail");
        return;
    }

加载补丁 jar ，这一部分的代码我们后面会详细展开

    //now we can load patch jar
    if (isEnabledForDex) {
        boolean loadTinkerJars = TinkerDexLoader.loadTinkerJars(app, patchVersionDirectory, oatDex, resultIntent, isSystemOTA);
        // 如果是 ota 的话，更新 oat 的文件夹路径
        if (isSystemOTA) {
            // update fingerprint after load success
            patchInfo.fingerPrint = Build.FINGERPRINT;
            patchInfo.oatDir = loadTinkerJars ? ShareConstants.INTERPRET_DEX_OPTIMIZE_PATH : ShareConstants.DEFAULT_DEX_OPTIMIZE_PATH;
            // reset to false
            oatModeChanged = false;
    
            if (!SharePatchInfo.rewritePatchInfoFileWithLock(patchInfoFile, patchInfo, patchInfoLockFile)) {
                ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_PATCH_REWRITE_PATCH_INFO_FAIL);
                Log.w(TAG, "tryLoadPatchFiles:onReWritePatchInfoCorrupted");
                return;
            }
            // update oat dir
            resultIntent.putExtra(ShareIntentUtil.INTENT_PATCH_OAT_DIR, patchInfo.oatDir);
        }
        if (!loadTinkerJars) {
            Log.w(TAG, "tryLoadPatchFiles:onPatchLoadDexesFail");
            return;
        }
    }

加载补丁资源，这一部分的代码我们后面会详细展开

    //now we can load patch resource
    if (isEnabledForResource) {
        boolean loadTinkerResources = TinkerResourceLoader.loadTinkerResources(app, patchVersionDirectory, resultIntent);
        if (!loadTinkerResources) {
            Log.w(TAG, "tryLoadPatchFiles:onPatchLoadResourcesFail");
            return;
        }
    }

补丁加载流程结束

    // Init component hotplug support.
    if (isEnabledForDex && isEnabledForResource) {
        ComponentHotplug.install(app, securityCheck);
    }
    
    //all is ok!
    ShareIntentUtil.setIntentReturnCode(resultIntent, ShareConstants.ERROR_LOAD_OK);
    Log.i(TAG, "tryLoadPatchFiles: load end, ok!");
    return;