写在前面的话
<p>
前面一篇Tinker相关的文章已经介绍了Tinker热修复框架的使用与整个的修复流程，那么这一篇就要开启Tinker的源码解析之路了。
首先简单说一下Tinker的原理，Tinker其实也是类似multidex的dex方式，将目标dex插入到数组最前面，主要是通过对比原dex文件（存在bug）与现dex文件（bug已修复）生成差异包，生成的差异包作为补丁包下发给客户端，客户端做一系列校验之后，将下发的差异包与本应用的dex文件合并成成全量的dex文件，并进行opt优化，当再次启动APP时候则加载优化过的全量dex文件，将dex文件插入到DexPathList 中 dexElements的前面。
所以Tinker其实是两个流程，一个是加载补丁包，另外一个是加载dex文件，两个的加载流程相对较长，这里分开说明，这一篇呢，主要介绍加载补丁包的流程。
补丁包加载流程
<p>
加载补丁包的方法如下
TinkerInstaller.onReceiveUpgradePatch(getApplicationContext(), "FilePath");
往下看发现调用了TinkerInstaller的onReceiveUpgradePatch方法
TinkerInstaller.java
public static void onReceiveUpgradePatch(Context context, String patchLocation) {
Tinker.with(context).getPatchListener().onPatchReceived(patchLocation);
}
这里调用了PatchListener的onPatchReceived方法
而PatchListener是一个接口，他的具体实现为SamplePatchListener方法，onPatchReceived在SamplePatchListener的父类DefaultPatchListener有实现，我们看下DefaultPatchListener中的onPatchReceived方法
如下
DefaultPatchListener.java
@Override
public int onPatchReceived(String path) {
int returnCode = patchCheck(path);
if (returnCode == ShareConstants.ERROR_PATCH_OK) {
TinkerPatchService.runPatchService(context, path);
} else {
Tinker.with(context).getLoadReporter().onLoadPatchListenerReceiveFail(new File(path), returnCode);
}
return returnCode;
}
首先这个检测了一下这个插件是否可用，通过SamplePatchListener的patchCheck方法来检测
SamplePatchListener.java
@Override
public int patchCheck(String path) {
File patchFile = new File(path);
TinkerLog.i(TAG, "receive a patch file: %s, file size:%d", path, SharePatchFileUtil.getFileOrDirectorySize(patchFile));
int returnCode = super.patchCheck(path);
if (returnCode == ShareConstants.ERROR_PATCH_OK) {
returnCode = Utils.checkForPatchRecover(NEW_PATCH_RESTRICTION_SPACE_SIZE_MIN, maxMemory);
}
if (returnCode == ShareConstants.ERROR_PATCH_OK) {
String patchMd5 = SharePatchFileUtil.getMD5(patchFile);
SharedPreferences sp = context.getSharedPreferences(ShareConstants.TINKER_SHARE_PREFERENCE_CONFIG, Context.MODE_MULTI_PROCESS);
//optional, only disable this patch file with md5
int fastCrashCount = sp.getInt(patchMd5, 0);
if (fastCrashCount >= SampleUncaughtExceptionHandler.MAX_CRASH_COUNT) {
returnCode = Utils.ERROR_PATCH_CRASH_LIMIT;
} else {
//for upgrade patch, version must be not the same
//for repair patch, we won't has the tinker load flag
Tinker tinker = Tinker.with(context);
if (tinker.isTinkerLoaded()) {
TinkerLoadResult tinkerLoadResult = tinker.getTinkerLoadResultIfPresent();
if (tinkerLoadResult != null) {
String currentVersion = tinkerLoadResult.currentVersion;
if (patchMd5.equals(currentVersion)) {
returnCode = Utils.ERROR_PATCH_ALREADY_APPLY;
}
}
}
}
//check whether retry so many times
if (returnCode == ShareConstants.ERROR_PATCH_OK) {
returnCode = UpgradePatchRetry.getInstance(context).onPatchListenerCheck(patchMd5)
? ShareConstants.ERROR_PATCH_OK : Utils.ERROR_PATCH_RETRY_COUNT_LIMIT;
}
}
// Warning, it is just a sample case, you don't need to copy all of these
// Interception some of the request
if (returnCode == ShareConstants.ERROR_PATCH_OK) {
Properties properties = ShareTinkerInternals.fastGetPatchPackageMeta(patchFile);
if (properties == null) {
returnCode = Utils.ERROR_PATCH_CONDITION_NOT_SATISFIED;
} else {
String platform = properties.getProperty(Utils.PLATFORM);
TinkerLog.i(TAG, "get platform:" + platform);
// check patch platform require
if (platform == null || !platform.equals(BuildInfo.PLATFORM)) {
returnCode = Utils.ERROR_PATCH_CONDITION_NOT_SATISFIED;
}
}
}
SampleTinkerReport.onTryApply(returnCode == ShareConstants.ERROR_PATCH_OK);
return returnCode;
}
这里对插件是否可用进行了判断，就不进行详细分析了
当插件可用时候returnCode为ERROR_PATCH_OK，当不可用则会log出来失败的errorcode
成功则调用
TinkerPatchService.runPatchService(context, path);
来启动TinkerPatchService这个IntentService，并且把插件的路径给传递到IntentService
TinkerPatchService通过onHandleIntent来接收传递过来的数据
TinkerPatchService.java
@Override
protected void onHandleIntent(Intent intent) {
final Context context = getApplicationContext();
Tinker tinker = Tinker.with(context);
tinker.getPatchReporter().onPatchServiceStart(intent);
if (intent == null) {
TinkerLog.e(TAG, "TinkerPatchService received a null intent, ignoring.");
return;
}
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;
increasingPriority();
PatchResult patchResult = new PatchResult();
try {
if (upgradePatchProcessor == null) {
throw new TinkerRuntimeException("upgradePatchProcessor is null.");
}
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;
AbstractResultService.runResultService(context, patchResult, getPatchResultExtra(intent));
}
这里首先调用了PatchReporter的onPatchServiceStart方法，而PatchReporter的实现为SamplePatchReporter
SamplePatchReporter.java
@Override
public void onPatchServiceStart(Intent intent) {
super.onPatchServiceStart(intent);
SampleTinkerReport.onApplyPatchServiceStart();
UpgradePatchRetry.getInstance(context).onPatchServiceStart(intent);
}
这里主要看UpgradePatchRetry的onPatchServiceStart方法
UpgradePatchRetry.java
public void onPatchServiceStart(Intent intent) {
if (!isRetryEnable) {
TinkerLog.w(TAG, "onPatchServiceStart retry disabled, just return");
return;
}
if (intent == null) {
TinkerLog.e(TAG, "onPatchServiceStart intent is null, just return");
return;
}
String path = TinkerPatchService.getPatchPathExtra(intent);
if (path == null) {
TinkerLog.w(TAG, "onPatchServiceStart patch path is null, just return");
return;
}
RetryInfo retryInfo;
File patchFile = new File(path);
String patchMd5 = SharePatchFileUtil.getMD5(patchFile);
if (patchMd5 == null) {
TinkerLog.w(TAG, "onPatchServiceStart patch md5 is null, just return");
return;
}
if (retryInfoFile.exists()) {
retryInfo = RetryInfo.readRetryProperty(retryInfoFile);
if (retryInfo.md5 == null || retryInfo.times == null || !patchMd5.equals(retryInfo.md5)) {
copyToTempFile(patchFile);
retryInfo.md5 = patchMd5;
retryInfo.times = "1";
} else {
int nowTimes = Integer.parseInt(retryInfo.times);
if (nowTimes >= RETRY_MAX_COUNT) {
SharePatchFileUtil.safeDeleteFile(tempPatchFile);
TinkerLog.w(TAG, "onPatchServiceStart retry more than max count, delete retry info file!");
return;
} else {
retryInfo.times = String.valueOf(nowTimes + 1);
}
}
} else {
copyToTempFile(patchFile);
retryInfo = new RetryInfo(patchMd5, "1");
}
RetryInfo.writeRetryProperty(retryInfoFile, retryInfo);
}
这里主要也做了一些验证，并且把文件复制一份到/data/data/tinker.sample.android/tinker_temp/路径下，然后把相关信息写入到配置文件中
在回到TinkerPatchService的onHandleIntent方法
主要看
result = upgradePatchProcessor.tryPatch(context, path, patchResult);
这个方法的实现在UpgradePatch中
UpgradePatch.java
@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 (!patchFile.isFile() || !patchFile.exists()) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:patch file is not found, just return");
return false;
}
//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;
}
//it is a new patch, so we should not find a exist
SharePatchInfo oldInfo = manager.getTinkerLoadResultIfPresent().patchInfo;
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
patchResult.patchVersion = patchMd5;
SharePatchInfo newInfo;
//already have patch
if (oldInfo != null) {
if (oldInfo.oldVersion == null || oldInfo.newVersion == null) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:onPatchInfoCorrupted");
manager.getPatchReporter().onPatchInfoCorrupted(patchFile, oldInfo.oldVersion, oldInfo.newVersion);
return false;
}
if (oldInfo.oldVersion.equals(patchMd5) || oldInfo.newVersion.equals(patchMd5)) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:onPatchVersionCheckFail");
manager.getPatchReporter().onPatchVersionCheckFail(patchFile, oldInfo, patchMd5);
return false;
}
newInfo = new SharePatchInfo(oldInfo.oldVersion, patchMd5, Build.FINGERPRINT);
} else {
newInfo = new SharePatchInfo("", patchMd5, Build.FINGERPRINT);
}
//check ok, we can real recover a new patch
final String patchDirectory = manager.getPatchDirectory().getAbsolutePath();
TinkerLog.i(TAG, "UpgradePatch tryPatch:patchMd5:%s", patchMd5);
final String patchName = SharePatchFileUtil.getPatchVersionDirectory(patchMd5);
final String patchVersionDirectory = patchDirectory + "/" + patchName;
TinkerLog.i(TAG, "UpgradePatch tryPatch:patchVersionDirectory:%s", patchVersionDirectory);
//it is a new patch, we first delete if there is any files
//don't delete dir for faster retry
// SharePatchFileUtil.deleteDir(patchVersionDirectory);
//copy file
File destPatchFile = new File(patchVersionDirectory + "/" + SharePatchFileUtil.getPatchVersionFile(patchMd5));
try {
SharePatchFileUtil.copyFileUsingStream(patchFile, destPatchFile);
TinkerLog.w(TAG, "UpgradePatch after %s size:%d, %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;
}
//we use destPatchFile instead of patchFile, because patchFile may be deleted during the patch process
if (!DexDiffPatchInternal.tryRecoverDexFiles(manager, signatureCheck, context, patchVersionDirectory, destPatchFile)) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:new patch recover, try patch dex failed");
return false;
}
if (!BsDiffPatchInternal.tryRecoverLibraryFiles(manager, signatureCheck, context, patchVersionDirectory, destPatchFile)) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:new patch recover, try patch library failed");
return false;
}
if (!ResDiffPatchInternal.tryRecoverResourceFiles(manager, signatureCheck, context, patchVersionDirectory, destPatchFile)) {
TinkerLog.e(TAG, "UpgradePatch tryPatch:new patch recover, try patch resource failed");
return false;
}
final File patchInfoFile = manager.getPatchInfoFile();
if (!SharePatchInfo.rewritePatchInfoFileWithLock(patchInfoFile, newInfo, SharePatchFileUtil.getPatchInfoLockFile(patchDirectory))) {
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;
}
}
这里首先初始化相关数据与相关验证，再将补丁文件拷贝到目标目录中
SharePatchFileUtil.copyFileUsingStream(patchFile, destPatchFile);
路径为/data/data/tinker.sample.android/tinker/patch-xxxxxx/patch-xxxxxx.apk
接下来就是调用DexDiffPatchInternal，BsDiffPatchInternal，ResDiffPatchInternal这些类的方法进行dexDiff差分的计算相关
至于相关差分的计算，由于比较复杂，我暂时还没有深入去看，暂时埋个坑在这里，等后面找时间去填上这个坑
在回到TinkerPatchService的onHandleIntent方法
后面调用了PatchReporter的onPatchResult，这个方法主要删除了上面拷贝在/data/data/tinker.sample.android/tinker_temp/的文件
接下来启动了AbstractResultService，并把插件的路径传递过去了
AbstractResultService的实现在SampleResultService类里面，SampleResultService的onPatchResult删除了原始的插件文件。
到这里插件加载分析就基本结束了
写在后面的话
<p>
插件加载分析结束了，但是却没有去分析dexDiff差分的计算，而这个dexDiff差分计算则是区分的Tinker与其他相同方案的热修复库，dexDiff是基于 Dex 的文件结构来下手，将产生变化的结构提取出来，产生的补丁非常小，而且在 diff 的过程中也处理了一些会造成补丁包很大的场景，所以等后面有时间将这一块补上，下一篇文章则是对dex文件加载进行源码分析了，peace~~~
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