本系列 Tinker 源码解析基于 Tinker v1.9.12
补丁合成流程
下发的补丁包其实并不能直接加载，因为补丁包只是差异包，需要和本地的 dex 、资源等进行合成后，得到全量的 dex 才能被完整地使用。这样也就避免了热修复中 dex 的 pre-verify 问题，也减少了补丁包的体积，方便用户下载。
补丁合成的入口在 TinkerInstaller.onReceiveUpgradePatch 方法
TinkerInstaller.onReceiveUpgradePatch
代码语言：javascript复制public static void onReceiveUpgradePatch(Context context, String patchLocation) {
Tinker.with(context).getPatchListener().onPatchReceived(patchLocation);
}这里的 PatchListener 有默认实现类，即 DefaultPatchListener 。
DefaultPatchListener.onPatchReceived
代码语言：javascript复制@Override
public int onPatchReceived(String path) {
File patchFile = new File(path);
// 对补丁进行校验
int returnCode = patchCheck(path, SharePatchFileUtil.getMD5(patchFile));
if (returnCode == ShareConstants.ERROR_PATCH_OK) {
// 通过的话就启动 :process 进程进行补丁合成
TinkerPatchService.runPatchService(context, path);
} else {
// 校验失败就回调 onLoadPatchListenerReceiveFail
Tinker.with(context).getLoadReporter().onLoadPatchListenerReceiveFail(new File(path), returnCode);
}
return returnCode;
}我们直接来看 TinkerPatchService.runPatchService 方法
TinkerPatchService.runPatchService
代码语言：javascript复制public static void runPatchService(final Context context, final String path) {
TinkerLog.i(TAG, "run patch service...");
Intent intent = new Intent(context, TinkerPatchService.class);
// path 就是补丁的路径
intent.putExtra(PATCH_PATH_EXTRA, path);
// RESULT_CLASS_EXTRA 一般默认就是 DefaultTinkerResultService
intent.putExtra(RESULT_CLASS_EXTRA, resultServiceClass.getName());
try {
enqueueWork(context, TinkerPatchService.class, JOB_ID, intent);
} catch (Throwable thr) {
TinkerLog.e(TAG, "run patch service fail, exception:" thr);
}
}在 runPatchService 中去启动了 TinkerPatchService 。TinkerPatchService 是跑在 :patch 进程中的。
TinkerPatchService 主要做的事情都在 onHandleWork 中
代码语言：javascript复制@Override
protected void onHandleWork(Intent intent) {
// 提高优先级
increasingPriority();
// 合成补丁
doApplyPatch(this, intent);
}首先是 increasingPriority 方法，目的就是提高 service 的优先级，具体的方案就是设置为前台服务
代码语言：javascript复制private void increasingPriority() {
if (Build.VERSION.SDK_INT >= 26) {
TinkerLog.i(TAG, "for system version >= Android O, we just ignore increasingPriority "
"job to avoid crash or toasts.");
return;
}
if ("ZUK".equals(Build.MANUFACTURER)) {
TinkerLog.i(TAG, "for ZUK device, we just ignore increasingPriority "
"job to avoid crash.");
return;
}
TinkerLog.i(TAG, "try to increase patch process priority");
// 设置为前台服务，提高优先级
try {
Notification notification = new Notification();
if (Build.VERSION.SDK_INT < 18) {
startForeground(notificationId, notification);
} else {
startForeground(notificationId, notification);
// start InnerService
startService(new Intent(this, InnerService.class));
}
} catch (Throwable e) {
TinkerLog.i(TAG, "try to increase patch process priority error:" e);
}
}接着是 doApplyPatch 方法，在这里做补丁合成的事
代码语言：javascript复制private static void doApplyPatch(Context context, Intent intent) {
// Since we may retry with IntentService, we should prevent
// racing here again.
if (!sIsPatchApplying.compareAndSet(false, true)) {
TinkerLog.w(TAG, "TinkerPatchService doApplyPatch is running by another runner.");
return;
}
Tinker tinker = Tinker.with(context);
tinker.getPatchReporter().onPatchServiceStart(intent);
if (intent == null) {
TinkerLog.e(TAG, "TinkerPatchService received a null intent, ignoring.");
return;
}
// 获取补丁文件的路径
String path = getPatchPathExtra(intent);
if (path == null) {
TinkerLog.e(TAG, "TinkerPatchService can't get the path extra, ignoring.");
return;
}
File patchFile = new File(path);
long begin = SystemClock.elapsedRealtime();
boolean result;
long cost;
Throwable e = null;
PatchResult patchResult = new PatchResult();
try {
if (upgradePatchProcessor == null) {
throw new TinkerRuntimeException("upgradePatchProcessor is null.");
}
// 处理补丁合成
result = upgradePatchProcessor.tryPatch(context, path, patchResult);
} catch (Throwable throwable) {
e = throwable;
result = false;
tinker.getPatchReporter().onPatchException(patchFile, e);
}
cost = SystemClock.elapsedRealtime() - begin;
tinker.getPatchReporter().
onPatchResult(patchFile, result, cost);
patchResult.isSuccess = result;
patchResult.rawPatchFilePath = path;
patchResult.costTime = cost;
patchResult.e = e;
// 补丁合成的结果回调给 DefaultResultService
AbstractResultService.runResultService(context, patchResult, getPatchResultExtra(intent));
sIsPatchApplying.set(false);
}upgradePatchProcessor 是一个接口，具体的实现类是 UpgradePatch 。
UpgradePatch.tryPatch
那么来看看 UpgradePatch.tryPatch ，方法比较长，分段来看吧。
首先是对 Tinker 自身开关的校验，然后对补丁文件的合法性进行校验。
代码语言：javascript复制@Override
public boolean tryPatch(Context context, String tempPatchPath, PatchResult patchResult) {
Tinker manager = Tinker.with(context);
final File patchFile = new File(tempPatchPath);
if (!manager.isTinkerEnabled() || !ShareTinkerInternals.isTinkerEnableWithSharedPreferences(context)) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:patch is disabled, just return");
return false;
}
if (!SharePatchFileUtil.isLegalFile(patchFile)) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:patch file is not found, just return");
return false;
}然后检查补丁包的签名以及 tinkerId , 这里的操作和加载补丁是一样的。
然后就是获取补丁文件的 md5 值
代码语言：javascript复制//check the signature, we should create a new checker
ShareSecurityCheck signatureCheck = new ShareSecurityCheck(context);
int returnCode = ShareTinkerInternals.checkTinkerPackage(context, manager.getTinkerFlags(), patchFile, signatureCheck);
if (returnCode != ShareConstants.ERROR_PACKAGE_CHECK_OK) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:onPatchPackageCheckFail");
manager.getPatchReporter().onPatchPackageCheckFail(patchFile, returnCode);
return false;
}
// 获取补丁文件的 md5
String patchMd5 = SharePatchFileUtil.getMD5(patchFile);
if (patchMd5 == null) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:patch md5 is null, just return");
return false;
}
//use md5 as version
// 用 md5 做版本号
patchResult.patchVersion = patchMd5;
TinkerLog.i(TAG, "UpgradePatch tryPatch:patchMd5:%s", patchMd5);接着，校验完成后，我们就来构造一个新的 patch.info 文件了。
代码语言：javascript复制//check ok, we can real recover a new patch
final String patchDirectory = manager.getPatchDirectory().getAbsolutePath();
// info.lock 文件
File patchInfoLockFile = SharePatchFileUtil.getPatchInfoLockFile(patchDirectory);
// patch.info 文件
File patchInfoFile = SharePatchFileUtil.getPatchInfoFile(patchDirectory);
// 读取出老的 patch.info 文件，可能存在 可能不存在
SharePatchInfo oldInfo = SharePatchInfo.readAndCheckPropertyWithLock(patchInfoFile, patchInfoLockFile);
//it is a new patch, so we should not find a exist
SharePatchInfo newInfo;
//如果有老的 patch.info 文件
if (oldInfo != null) {
if (oldInfo.oldVersion == null || oldInfo.newVersion == null || oldInfo.oatDir == null) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:onPatchInfoCorrupted");
manager.getPatchReporter().onPatchInfoCorrupted(patchFile, oldInfo.oldVersion, oldInfo.newVersion);
return false;
}
if (!SharePatchFileUtil.checkIfMd5Valid(patchMd5)) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:onPatchVersionCheckFail md5 %s is valid", patchMd5);
manager.getPatchReporter().onPatchVersionCheckFail(patchFile, oldInfo, patchMd5);
return false;
}
// if it is interpret now, use changing flag to wait main process
final String finalOatDir = oldInfo.oatDir.equals(ShareConstants.INTERPRET_DEX_OPTIMIZE_PATH)
? ShareConstants.CHANING_DEX_OPTIMIZE_PATH : oldInfo.oatDir;
// 构造新的 patch.info
newInfo = new SharePatchInfo(oldInfo.oldVersion, patchMd5, false, Build.FINGERPRINT, finalOatDir);
} else {
// 构造新的 patch.info
newInfo = new SharePatchInfo("", patchMd5, false, Build.FINGERPRINT, ShareConstants.DEFAULT_DEX_OPTIMIZE_PATH);
}再接下来，就是把补丁包复制到私有目录中
具体的路径也就是之前在加载补丁中遇到的 /data/data/应用包名/tinker/patch-xxxxxx/patch-xxxxxx.apk
代码语言：javascript复制//it is a new patch, we first delete if there is any files
//don't delete dir for faster retry
// SharePatchFileUtil.deleteDir(patchVersionDirectory);
final String patchName = SharePatchFileUtil.getPatchVersionDirectory(patchMd5);
final String patchVersionDirectory = patchDirectory "/" patchName;
TinkerLog.i(TAG, "UpgradePatch tryPatch:patchVersionDirectory:%s", patchVersionDirectory);
//copy file
File destPatchFile = new File(patchVersionDirectory "/" SharePatchFileUtil.getPatchVersionFile(patchMd5));
try {
// check md5 first
if (!patchMd5.equals(SharePatchFileUtil.getMD5(destPatchFile))) {
// 复制补丁包到 /data/data/ 中
SharePatchFileUtil.copyFileUsingStream(patchFile, destPatchFile);
TinkerLog.w(TAG, "UpgradePatch copy patch file, src file: %s size: %d, dest file: %s size:%d", patchFile.getAbsolutePath(), patchFile.length(),
destPatchFile.getAbsolutePath(), destPatchFile.length());
}
} catch (IOException e) {
// e.printStackTrace();
TinkerLog.e(TAG, "UpgradePatch tryPatch:copy patch file fail from %s to %s", patchFile.getPath(), destPatchFile.getPath());
manager.getPatchReporter().onPatchTypeExtractFail(patchFile, destPatchFile, patchFile.getName(), ShareConstants.TYPE_PATCH_FILE);
return false;
}复制好之后，就是把补丁包和基准包进行整合了
代码语言：javascript复制//we use destPatchFile instead of patchFile, because patchFile may be deleted during the patch process
// 合成 dex
if (!DexDiffPatchInternal.tryRecoverDexFiles(manager, signatureCheck, context, patchVersionDirectory, destPatchFile)) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:new patch recover, try patch dex failed");
return false;
}
// 合成 so 文件
if (!BsDiffPatchInternal.tryRecoverLibraryFiles(manager, signatureCheck, context, patchVersionDirectory, destPatchFile)) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:new patch recover, try patch library failed");
return false;
}
// 合成资源文件
if (!ResDiffPatchInternal.tryRecoverResourceFiles(manager, signatureCheck, context, patchVersionDirectory, destPatchFile)) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:new patch recover, try patch resource failed");
return false;
}这里面的三个合成代码我们到后面的章节再分析，这里先跳过了。
合成完后，还要对 dex 进行opt优化
代码语言：javascript复制// check dex opt file at last, some phone such as VIVO/OPPO like to change dex2oat to interpreted
if (!DexDiffPatchInternal.waitAndCheckDexOptFile(patchFile, manager)) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:new patch recover, check dex opt file failed");
return false;
}最后，就是把结果重新写入到 patch.info ，这样在加载补丁的流程中就能加载新补丁了。
代码语言：javascript复制if (!SharePatchInfo.rewritePatchInfoFileWithLock(patchInfoFile, newInfo, patchInfoLockFile)) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:new patch recover, rewrite patch info failed");
manager.getPatchReporter().onPatchInfoCorrupted(patchFile, newInfo.oldVersion, newInfo.newVersion);
return false;
}
TinkerLog.w(TAG, "UpgradePatch tryPatch: done, it is ok");
return true;over ，整个合成补丁的流程讲完了，这里还留了三个坑：
- dex 文件的合成
- so 文件的合成
- 资源文件的合成
到后面再讲吧。
