Tinker源码分析(七):dex合成流程
本系列 Tinker 源码解析基于 Tinker v1.9.12
前面讲到了 Tinker 安装补丁的流程，现在就详细地来看下 dex 合成的代码。代码入口就在 DexDiffPatchInternal.tryRecoverDexFiles 中。
UpgradePatch
//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;
}直接调用了 DexDiffPatchInternal.tryRecoverDexFiles 方法。
tryRecoverDexFiles
protected static boolean tryRecoverDexFiles(Tinker manager, ShareSecurityCheck checker, Context context,
String patchVersionDirectory, File patchFile) {
// 检查是否开启支持dex补丁开关
if (!manager.isEnabledForDex()) {
TinkerLog.w(TAG, "patch recover, dex is not enabled");
return true;
}
// 检查补丁包中的 dex_meta.txt 是否存在
String dexMeta = checker.getMetaContentMap().get(DEX_META_FILE);
if (dexMeta == null) {
TinkerLog.w(TAG, "patch recover, dex is not contained");
return true;
}
long begin = SystemClock.elapsedRealtime();
// 到这个方法中执行具体的操作
boolean result = patchDexExtractViaDexDiff(context, patchVersionDirectory, dexMeta, patchFile);
long cost = SystemClock.elapsedRealtime() - begin;
TinkerLog.i(TAG, "recover dex result:%b, cost:%d", result, cost);
return result;
}tryRecoverDexFiles 方法开头做了些校验，最后又到 patchDexExtractViaDexDiff 中。
patchDexExtractViaDexDiff
private static boolean patchDexExtractViaDexDiff(Context context, String patchVersionDirectory, String meta, final File patchFile) {
// dex补丁合成的路径
String dir = patchVersionDirectory + "/" + DEX_PATH + "/";
// extractDexDiffInternals 这个方法是重点！！！
if (!extractDexDiffInternals(context, dir, meta, patchFile, TYPE_DEX)) {
TinkerLog.w(TAG, "patch recover, extractDiffInternals fail");
return false;
}
// 把 tinker/patch-xxxxx/dex/ 下面的文件校验下，看看是否是合法的dex文件
File dexFiles = new File(dir);
File[] files = dexFiles.listFiles();
List<File> legalFiles = new ArrayList<>();
// may have directory in android o
if (files != null) {
for (File file : files) {
final String fileName = file.getName();
if (file.isFile()
&& (fileName.endsWith(ShareConstants.DEX_SUFFIX)
|| fileName.endsWith(ShareConstants.JAR_SUFFIX)
|| fileName.endsWith(ShareConstants.PATCH_SUFFIX))
) {
legalFiles.add(file);
}
}
}
TinkerLog.i(TAG, "legal files to do dexopt: " + legalFiles);
// 对 dex 做 opt 优化
final String optimizeDexDirectory = patchVersionDirectory + "/" + DEX_OPTIMIZE_PATH + "/";
return dexOptimizeDexFiles(context, legalFiles, optimizeDexDirectory, patchFile);
}在 patchDexExtractViaDexDiff 中可以看到， dex 文件合成之后，会对其做 opt 优化。而合成的代码就在 extractDexDiffInternals 里面。
extractDexDiffInternals 方法有点长。按照老规矩，我们分段来看。
extractDexDiffInternals
private static boolean extractDexDiffInternals(Context context, String dir, String meta, File patchFile, int type) {
// 读取 dex_meta.txt 中的信息
patchList.clear();
ShareDexDiffPatchInfo.parseDexDiffPatchInfo(meta, patchList);
if (patchList.isEmpty()) {
TinkerLog.w(TAG, "extract patch list is empty! type:%s:", ShareTinkerInternals.getTypeString(type));
return true;
}首先读取 dex_meta.txt 中的信息，用“,”分割，保存到 patchList 中。
下面贴出一份 dex_meta.txt 的示例：
classes.dex,,1a6e6d6a40eff95aa33ab06e07acd413,1a6e6d6a40eff95aa33ab06e07acd413,d865f383455abd6e3f70096109543644,2999635299,712828526,jar
test.dex,,56900442eb5b7e1de45449d0685e6e00,56900442eb5b7e1de45449d0685e6e00,0,0,0,jardex_meta.txt 记录着
- name ：补丁 dex 名字
- path ：补丁 dex 路径
- destMd5InDvm ：合成新 dex 在 dvm 中的 md5 值
- destMd5InArt ：合成新 dex 在 art 中的 md5 值
- dexDiffMd5 ：补丁包 dex 文件的 md5 值
- oldDexCrc ：基准包中对应 dex 的 crc 值
- newDexCrc ：合成新 dex 的 crc 值
- dexMode ：dex 类型，为 jar 类型
接着往下看。
File directory = new File(dir);
if (!directory.exists()) {
directory.mkdirs();
}
//I think it is better to extract the raw files from apk
Tinker manager = Tinker.with(context);
ZipFile apk = null;
ZipFile patch = null;
try {
ApplicationInfo applicationInfo = context.getApplicationInfo();
if (applicationInfo == null) {
// Looks like running on a test Context, so just return without patching.
TinkerLog.w(TAG, "applicationInfo == null!!!!");
return false;
}
// 获取到基准包apk的路径
String apkPath = applicationInfo.sourceDir;
// 基准包文件
apk = new ZipFile(apkPath);
// 补丁包文件
patch = new ZipFile(patchFile);
if (checkClassNDexFiles(dir)) {
TinkerLog.w(TAG, "class n dex file %s is already exist, and md5 match, just continue", ShareConstants.CLASS_N_APK_NAME);
return true;
}然后获取基本包和补丁包的路径，为下面合成做准备。
// 遍历 ShareDexDiffPatchInfo
for (ShareDexDiffPatchInfo info : patchList) {
long start = System.currentTimeMillis();
// 补丁dex文件路径
final String infoPath = info.path;
String patchRealPath;
if (infoPath.equals("")) {
patchRealPath = info.rawName;
} else {
patchRealPath = info.path + "/" + info.rawName;
}
String dexDiffMd5 = info.dexDiffMd5;
String oldDexCrc = info.oldDexCrC;
// 如果是 dvm 虚拟机环境，但是补丁dex是art环境的，就跳过
if (!isVmArt && info.destMd5InDvm.equals("0")) {
TinkerLog.w(TAG, "patch dex %s is only for art, just continue", patchRealPath);
continue;
}
String extractedFileMd5 = isVmArt ? info.destMd5InArt : info.destMd5InDvm;
// 检查 md5 值
if (!SharePatchFileUtil.checkIfMd5Valid(extractedFileMd5)) {
TinkerLog.w(TAG, "meta file md5 invalid, type:%s, name: %s, md5: %s", ShareTinkerInternals.getTypeString(type), info.rawName, extractedFileMd5);
manager.getPatchReporter().onPatchPackageCheckFail(patchFile, BasePatchInternal.getMetaCorruptedCode(type));
return false;
}
File extractedFile = new File(dir + info.realName);
// 如果合成的dex文件已经存在了
if (extractedFile.exists()) {
// 就校验合成的 dex 文件md5值，如果通过就跳过
if (SharePatchFileUtil.verifyDexFileMd5(extractedFile, extractedFileMd5)) {
//it is ok, just continue
TinkerLog.w(TAG, "dex file %s is already exist, and md5 match, just continue", extractedFile.getPath());
continue;
} else {
TinkerLog.w(TAG, "have a mismatch corrupted dex " + extractedFile.getPath());
// 否则删除文件
extractedFile.delete();
}
} else {
extractedFile.getParentFile().mkdirs();
}从这里开始，就是遍历 patchList 中的记录，进行一个个 dex 文件合成了。一开头会去校验合成的文件是否存在，存在的话就跳过，进行下一个。
ZipEntry patchFileEntry = patch.getEntry(patchRealPath);
ZipEntry rawApkFileEntry = apk.getEntry(patchRealPath);
if (oldDexCrc.equals("0")) {
if (patchFileEntry == null) {
TinkerLog.w(TAG, "patch entry is null. path:" + patchRealPath);
manager.getPatchReporter().onPatchTypeExtractFail(patchFile, extractedFile, info.rawName, type);
return false;
}
//it is a new file, but maybe we need to repack the dex file
if (!extractDexFile(patch, patchFileEntry, extractedFile, info)) {
TinkerLog.w(TAG, "Failed to extract raw patch file " + extractedFile.getPath());
manager.getPatchReporter().onPatchTypeExtractFail(patchFile, extractedFile, info.rawName, type);
return false;
}
} 如果 oldDexCrc 为0，就说明基准包中对应的 oldDex 文件不存在，直接按照 patch 信息重新打包 dex 即可。
// 如果 dexDiffMd5 为 0， 就说明补丁包中没有这个dex，但是基准包中存在
else if (dexDiffMd5.equals("0")) {
// skip process old dex for real dalvik vm
// 如果是 dvm 环境的无须做处理
if (!isVmArt) {
continue;
}
// 检查基准包中的 dex 是否为空
if (rawApkFileEntry == null) {
TinkerLog.w(TAG, "apk entry is null. path:" + patchRealPath);
manager.getPatchReporter().onPatchTypeExtractFail(patchFile, extractedFile, info.rawName, type);
return false;
}
//check source crc instead of md5 for faster
// 检查基准包中的 dex 的 crc 值和 dex_meta.txt 中是否一致
String rawEntryCrc = String.valueOf(rawApkFileEntry.getCrc());
if (!rawEntryCrc.equals(oldDexCrc)) {
TinkerLog.e(TAG, "apk entry %s crc is not equal, expect crc: %s, got crc: %s", patchRealPath, oldDexCrc, rawEntryCrc);
manager.getPatchReporter().onPatchTypeExtractFail(patchFile, extractedFile, info.rawName, type);
return false;
}
// Small patched dex generating strategy was disabled, we copy full original dex directly now.
//patchDexFile(apk, patch, rawApkFileEntry, null, info, smallPatchInfoFile, extractedFile);
// 直接复制 ：copy full original dex directly now.
extractDexFile(apk, rawApkFileEntry, extractedFile, info);
// 复制完后校验一下md5值是否一致
if (!SharePatchFileUtil.verifyDexFileMd5(extractedFile, extractedFileMd5)) {
TinkerLog.w(TAG, "Failed to recover dex file when verify patched dex: " + extractedFile.getPath());
manager.getPatchReporter().onPatchTypeExtractFail(patchFile, extractedFile, info.rawName, type);
SharePatchFileUtil.safeDeleteFile(extractedFile);
return false;
}
} 上面这段代码用来处理基准包中有 oldDex ，但是补丁包中没有 dex 的情况。
如果是 dvm 环境就跳过不处理即可，如果是 art 环境就把 oldDex 复制过去。
else {
// 检查补丁包中 dex 是否存在
if (patchFileEntry == null) {
TinkerLog.w(TAG, "patch entry is null. path:" + patchRealPath);
manager.getPatchReporter().onPatchTypeExtractFail(patchFile, extractedFile, info.rawName, type);
return false;
}
// 检查补丁包中的 dex md5值是否合法
if (!SharePatchFileUtil.checkIfMd5Valid(dexDiffMd5)) {
TinkerLog.w(TAG, "meta file md5 invalid, type:%s, name: %s, md5: %s", ShareTinkerInternals.getTypeString(type), info.rawName, dexDiffMd5);
manager.getPatchReporter().onPatchPackageCheckFail(patchFile, BasePatchInternal.getMetaCorruptedCode(type));
return false;
}
// 检查基准包中的 dex 是否存在
if (rawApkFileEntry == null) {
TinkerLog.w(TAG, "apk entry is null. path:" + patchRealPath);
manager.getPatchReporter().onPatchTypeExtractFail(patchFile, extractedFile, info.rawName, type);
return false;
}
// 检查基准包中的 dex 的 crc 值是否一致
String rawEntryCrc = String.valueOf(rawApkFileEntry.getCrc());
if (!rawEntryCrc.equals(oldDexCrc)) {
TinkerLog.e(TAG, "apk entry %s crc is not equal, expect crc: %s, got crc: %s", patchRealPath, oldDexCrc, rawEntryCrc);
manager.getPatchReporter().onPatchTypeExtractFail(patchFile, extractedFile, info.rawName, type);
return false;
}
// 执行合成操作
patchDexFile(apk, patch, rawApkFileEntry, patchFileEntry, info, extractedFile);
// 检查合成出来的dex的 md5 值是否一致
if (!SharePatchFileUtil.verifyDexFileMd5(extractedFile, extractedFileMd5)) {
TinkerLog.w(TAG, "Failed to recover dex file when verify patched dex: " + extractedFile.getPath());
manager.getPatchReporter().onPatchTypeExtractFail(patchFile, extractedFile, info.rawName, type);
SharePatchFileUtil.safeDeleteFile(extractedFile);
return false;
}
TinkerLog.w(TAG, "success recover dex file: %s, size: %d, use time: %d",
extractedFile.getPath(), extractedFile.length(), (System.currentTimeMillis() - start));
}
}
if (!mergeClassNDexFiles(context, patchFile, dir)) {
return false;
}
} catch (Throwable e) {
throw new TinkerRuntimeException("patch " + ShareTinkerInternals.getTypeString(type) + " extract failed (" + e.getMessage() + ").", e);
} finally {
SharePatchFileUtil.closeZip(apk);
SharePatchFileUtil.closeZip(patch);
}
return true;
}最后，就是基准包和补丁包中都存在对应 dex 的情况了。
代码一开始就是一堆的各种校验，都通过后，调用 patchDexFile 执行合成操作。合成完后再对合成的 dex 进行md5校验。
patchDexFile
private static void patchDexFile(
ZipFile baseApk, ZipFile patchPkg, ZipEntry oldDexEntry, ZipEntry patchFileEntry,
ShareDexDiffPatchInfo patchInfo, File patchedDexFile) throws IOException {
InputStream oldDexStream = null;
InputStream patchFileStream = null;
try {
// 基准包 dex 文件输入流
oldDexStream = new BufferedInputStream(baseApk.getInputStream(oldDexEntry));
// 补丁包 dex 文件输入流
patchFileStream = (patchFileEntry != null ? new BufferedInputStream(patchPkg.getInputStream(patchFileEntry)) : null);
final boolean isRawDexFile = SharePatchFileUtil.isRawDexFile(patchInfo.rawName);
if (!isRawDexFile || patchInfo.isJarMode) {
ZipOutputStream zos = null;
try {
// 合成 dex 文件的输出流
zos = new ZipOutputStream(new BufferedOutputStream(new FileOutputStream(patchedDexFile)));
zos.putNextEntry(new ZipEntry(ShareConstants.DEX_IN_JAR));
// Old dex is not a raw dex file.
if (!isRawDexFile) {
ZipInputStream zis = null;
try {
zis = new ZipInputStream(oldDexStream);
ZipEntry entry;
while ((entry = zis.getNextEntry()) != null) {
if (ShareConstants.DEX_IN_JAR.equals(entry.getName())) break;
}
if (entry == null) {
throw new TinkerRuntimeException("can't recognize zip dex format file:" + patchedDexFile.getAbsolutePath());
}
new DexPatchApplier(zis, patchFileStream).executeAndSaveTo(zos);
} finally {
StreamUtil.closeQuietly(zis);
}
} else {
new DexPatchApplier(oldDexStream, patchFileStream).executeAndSaveTo(zos);
}
zos.closeEntry();
} finally {
StreamUtil.closeQuietly(zos);
}
} else {
new DexPatchApplier(oldDexStream, patchFileStream).executeAndSaveTo(patchedDexFile);
}
} finally {
StreamUtil.closeQuietly(oldDexStream);
StreamUtil.closeQuietly(patchFileStream);
}
}在 patchDexFile 中，拿到基准包 dex 文件的 InputStream 和补丁包 dex 文件的 InputStream ，然后利用 DexPatchApplier 把这两个流合成一个 dex 文件。
public void executeAndSaveTo(OutputStream out) throws IOException {
// Before executing, we should check if this patch can be applied to
// old dex we passed in.
byte[] oldDexSign = this.oldDex.computeSignature(false);
if (oldDexSign == null) {
throw new IOException("failed to compute old dex's signature.");
}
if (this.patchFile == null) {
throw new IllegalArgumentException("patch file is null.");
}
byte[] oldDexSignInPatchFile = this.patchFile.getOldDexSignature();
if (CompareUtils.uArrCompare(oldDexSign, oldDexSignInPatchFile) != 0) {
throw new IOException(
String.format(
"old dex signature mismatch! expected: %s, actual: %s",
Arrays.toString(oldDexSign),
Arrays.toString(oldDexSignInPatchFile)
)
);
}
// Firstly, set sections' offset after patched, sort according to their offset so that
// the dex lib of aosp can calculate section size.
TableOfContents patchedToc = this.patchedDex.getTableOfContents();
patchedToc.header.off = 0;
patchedToc.header.size = 1;
patchedToc.mapList.size = 1;
patchedToc.stringIds.off
= this.patchFile.getPatchedStringIdSectionOffset();
patchedToc.typeIds.off
= this.patchFile.getPatchedTypeIdSectionOffset();
patchedToc.typeLists.off
= this.patchFile.getPatchedTypeListSectionOffset();
patchedToc.protoIds.off
= this.patchFile.getPatchedProtoIdSectionOffset();
patchedToc.fieldIds.off
= this.patchFile.getPatchedFieldIdSectionOffset();
patchedToc.methodIds.off
= this.patchFile.getPatchedMethodIdSectionOffset();
patchedToc.classDefs.off
= this.patchFile.getPatchedClassDefSectionOffset();
patchedToc.mapList.off
= this.patchFile.getPatchedMapListSectionOffset();
patchedToc.stringDatas.off
= this.patchFile.getPatchedStringDataSectionOffset();
patchedToc.annotations.off
= this.patchFile.getPatchedAnnotationSectionOffset();
patchedToc.annotationSets.off
= this.patchFile.getPatchedAnnotationSetSectionOffset();
patchedToc.annotationSetRefLists.off
= this.patchFile.getPatchedAnnotationSetRefListSectionOffset();
patchedToc.annotationsDirectories.off
= this.patchFile.getPatchedAnnotationsDirectorySectionOffset();
patchedToc.encodedArrays.off
= this.patchFile.getPatchedEncodedArraySectionOffset();
patchedToc.debugInfos.off
= this.patchFile.getPatchedDebugInfoSectionOffset();
patchedToc.codes.off
= this.patchFile.getPatchedCodeSectionOffset();
patchedToc.classDatas.off
= this.patchFile.getPatchedClassDataSectionOffset();
patchedToc.fileSize
= this.patchFile.getPatchedDexSize();
Arrays.sort(patchedToc.sections);
patchedToc.computeSizesFromOffsets();
// Secondly, run patch algorithms according to sections' dependencies.
this.stringDataSectionPatchAlg = new StringDataSectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.typeIdSectionPatchAlg = new TypeIdSectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.protoIdSectionPatchAlg = new ProtoIdSectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.fieldIdSectionPatchAlg = new FieldIdSectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.methodIdSectionPatchAlg = new MethodIdSectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.classDefSectionPatchAlg = new ClassDefSectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.typeListSectionPatchAlg = new TypeListSectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.annotationSetRefListSectionPatchAlg = new AnnotationSetRefListSectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.annotationSetSectionPatchAlg = new AnnotationSetSectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.classDataSectionPatchAlg = new ClassDataSectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.codeSectionPatchAlg = new CodeSectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.debugInfoSectionPatchAlg = new DebugInfoItemSectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.annotationSectionPatchAlg = new AnnotationSectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.encodedArraySectionPatchAlg = new StaticValueSectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.annotationsDirectorySectionPatchAlg = new AnnotationsDirectorySectionPatchAlgorithm(
patchFile, oldDex, patchedDex, oldToPatchedIndexMap
);
this.stringDataSectionPatchAlg.execute();
this.typeIdSectionPatchAlg.execute();
this.typeListSectionPatchAlg.execute();
this.protoIdSectionPatchAlg.execute();
this.fieldIdSectionPatchAlg.execute();
this.methodIdSectionPatchAlg.execute();
this.annotationSectionPatchAlg.execute();
this.annotationSetSectionPatchAlg.execute();
this.annotationSetRefListSectionPatchAlg.execute();
this.annotationsDirectorySectionPatchAlg.execute();
this.debugInfoSectionPatchAlg.execute();
this.codeSectionPatchAlg.execute();
this.classDataSectionPatchAlg.execute();
this.encodedArraySectionPatchAlg.execute();
this.classDefSectionPatchAlg.execute();
// Thirdly, write header, mapList. Calculate and write patched dex's sign and checksum.
Dex.Section headerOut = this.patchedDex.openSection(patchedToc.header.off);
patchedToc.writeHeader(headerOut);
Dex.Section mapListOut = this.patchedDex.openSection(patchedToc.mapList.off);
patchedToc.writeMap(mapListOut);
this.patchedDex.writeHashes();
// Finally, write patched dex to file.
this.patchedDex.writeTo(out);
}而 DexPatchApplier 里面合流操作的代码是需要根据 Tinker 的 DexDiff 算法来的。大致就是把两个 Dex 文件的每个分区做 merge 操作。
这里先留一个坑。等以后把 DexDiff 算法看明白了再补上。
另外，dodola 写了一篇 Tinker Dexdiff算法解析，有需要的同学可以看下。
那么 dex 合成的流程就到这吧。
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原始发表：2019.03.24 ，如有侵权请联系 cloudcommunity@tencent.com 删除
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