編輯:關於android開發
上一篇文章介紹了Dex文件的熱更新流程,本文將會分析Tinker中對資源文件的熱更新流程。
同Dex,資源文件的熱更新同樣包括三個部分:資源補丁生成,資源補丁合成及資源補丁加載。
本系列將從以下三個方面對Tinker進行源碼解析:
轉載請標明本文來源:http://www.cnblogs.com/yyangblog/p/6252490.html
更多內容歡迎star作者的github:https://github.com/LaurenceYang/article
如果發現本文有什麼問題和任何建議,也隨時歡迎交流~
ResDiffDecoder.patch(File oldFile, File newFile)主要負責資源文件補丁的生成。
如果是新增的資源,直接將資源文件拷貝到目標目錄。
如果是修改的資源文件則使用dealWithModeFile函數處理。
1 // 如果是新增的資源,直接將資源文件拷貝到目標目錄. 2 if (oldFile == null || !oldFile.exists()) { 3 if (Utils.checkFileInPattern(config.mResIgnoreChangePattern, name)) { 4 Logger.e("found add resource: " + name + " ,but it match ignore change pattern, just ignore!"); 5 return false; 6 } 7 FileOperation.copyFileUsingStream(newFile, outputFile); 8 addedSet.add(name); 9 writeResLog(newFile, oldFile, TypedValue.ADD); 10 return true; 11 } 12 ... 13 // 新舊資源文件的md5一樣,表示沒有修改. 14 if (oldMd5 != null && oldMd5.equals(newMd5)) { 15 return false; 16 } 17 ... 18 // 修改的資源文件使用dealWithModeFile函數處理. 19 dealWithModeFile(name, newMd5, oldFile, newFile, outputFile);
dealWithModeFile會對文件大小進行判斷,如果大於設定值(默認100Kb),采用bsdiff算法對新舊文件比較生成補丁包,從而降低補丁包的大小。
如果小於設定值,則直接將該文件加入修改列表,並直接將該文件拷貝到目標目錄。
1 if (checkLargeModFile(newFile)) { //大文件采用bsdiff算法 2 if (!outputFile.getParentFile().exists()) { 3 outputFile.getParentFile().mkdirs(); 4 } 5 BSDiff.bsdiff(oldFile, newFile, outputFile); 6 //treat it as normal modify 7 // 對生成的diff文件大小和newFile進行比較,只有在達到我們的壓縮效果後才使用diff文件 8 if (Utils.checkBsDiffFileSize(outputFile, newFile)) { 9 LargeModeInfo largeModeInfo = new LargeModeInfo(); 10 largeModeInfo.path = newFile; 11 largeModeInfo.crc = FileOperation.getFileCrc32(newFile); 12 largeModeInfo.md5 = newMd5; 13 largeModifiedSet.add(name); 14 largeModifiedMap.put(name, largeModeInfo); 15 writeResLog(newFile, oldFile, TypedValue.LARGE_MOD); 16 return true; 17 } 18 } 19 modifiedSet.add(name); // 加入修改列表 20 FileOperation.copyFileUsingStream(newFile, outputFile); 21 writeResLog(newFile, oldFile, TypedValue.MOD); 22 return false;
BsDiff屬於二進制比較,其具體實現大家可以自行百度。
ResDiffDecoder.onAllPatchesEnd()中會加入一個測試用的資源文件,放在assets目錄下,用於在加載補丁時判斷其是否加在成功。
這一步同時會向res_meta.txt文件中寫入資源更改的信息。
1 //加入一個測試用的資源文件 2 addAssetsFileForTestResource(); 3 ... 4 //first, write resource meta first 5 //use resources.arsc's base crc to identify base.apk 6 String arscBaseCrc = FileOperation.getZipEntryCrc(config.mOldApkFile, TypedValue.RES_ARSC); 7 String arscMd5 = FileOperation.getZipEntryMd5(extractToZip, TypedValue.RES_ARSC); 8 if (arscBaseCrc == null || arscMd5 == null) { 9 throw new TinkerPatchException("can't find resources.arsc's base crc or md5"); 10 } 11 12 String resourceMeta = Utils.getResourceMeta(arscBaseCrc, arscMd5); 13 writeMetaFile(resourceMeta); 14 15 //pattern 16 String patternMeta = TypedValue.PATTERN_TITLE; 17 HashSet<String> patterns = new HashSet<>(config.mResRawPattern); 18 //we will process them separate 19 patterns.remove(TypedValue.RES_MANIFEST); 20 21 writeMetaFile(patternMeta + patterns.size()); 22 //write pattern 23 for (String item : patterns) { 24 writeMetaFile(item); 25 } 26 //write meta file, write large modify first 27 writeMetaFile(largeModifiedSet, TypedValue.LARGE_MOD); 28 writeMetaFile(modifiedSet, TypedValue.MOD); 29 writeMetaFile(addedSet, TypedValue.ADD); 30 writeMetaFile(deletedSet, TypedValue.DEL);
最後的res_meta.txt文件的格式范例如下:
resources_out.zip,4019114434,6148149bd5ed4e0c2f5357c6e2c577d6 pattern:4 resources.arsc r/* res/* assets/* modify:1 r/g/ag.xml add:1 assets/only_use_to_test_tinker_resource.txt
到此,資源文件的補丁打包流程結束。
ResDiffPatchInternal.tryRecoverResourceFiles會調用extractResourceDiffInternals進行補丁的合成。
合成過程比較簡單,沒有使用bsdiff生成的文件直接寫入到resources.apk文件;
使用bsdiff生成的文件則采用bspatch算法合成資源文件,然後將合成文件寫入resouces.apk文件。
最後,生成的resouces.apk文件會存放到/data/data/${package_name}/tinker/res對應的目錄下。
1 / 首先讀取res_meta.txt的數據 2 ShareResPatchInfo.parseAllResPatchInfo(meta, resPatchInfo); 3 // 驗證resPatchInfo的MD5是否合法 4 if (!SharePatchFileUtil.checkIfMd5Valid(resPatchInfo.resArscMd5)) { 5 ... 6 // resources.apk 7 File resOutput = new File(directory, ShareConstants.RES_NAME); 8 9 // 該函數裡面會對largeMod的文件進行合成,合成的算法也是采用bsdiff 10 if (!checkAndExtractResourceLargeFile(context, apkPath, directory, patchFile, resPatchInfo, type, isUpgradePatch)) { 11 12 // 基於oldapk,合並補丁後將這些資源文件寫入resources.apk文件中 13 while (entries.hasMoreElements()) { 14 TinkerZipEntry zipEntry = entries.nextElement(); 15 if (zipEntry == null) { 16 throw new TinkerRuntimeException("zipEntry is null when get from oldApk"); 17 } 18 String name = zipEntry.getName(); 19 if (ShareResPatchInfo.checkFileInPattern(resPatchInfo.patterns, name)) { 20 //won't contain in add set. 21 if (!resPatchInfo.deleteRes.contains(name) 22 && !resPatchInfo.modRes.contains(name) 23 && !resPatchInfo.largeModRes.contains(name) 24 && !name.equals(ShareConstants.RES_MANIFEST)) { 25 ResUtil.extractTinkerEntry(oldApk, zipEntry, out); 26 totalEntryCount++; 27 } 28 } 29 } 30 31 //process manifest 32 TinkerZipEntry manifestZipEntry = oldApk.getEntry(ShareConstants.RES_MANIFEST); 33 if (manifestZipEntry == null) { 34 TinkerLog.w(TAG, "manifest patch entry is null. path:" + ShareConstants.RES_MANIFEST); 35 manager.getPatchReporter().onPatchTypeExtractFail(patchFile, resOutput, ShareConstants.RES_MANIFEST, type, isUpgradePatch); 36 return false; 37 } 38 ResUtil.extractTinkerEntry(oldApk, manifestZipEntry, out); 39 totalEntryCount++; 40 41 for (String name : resPatchInfo.largeModRes) { 42 TinkerZipEntry largeZipEntry = oldApk.getEntry(name); 43 if (largeZipEntry == null) { 44 TinkerLog.w(TAG, "large patch entry is null. path:" + name); 45 manager.getPatchReporter().onPatchTypeExtractFail(patchFile, resOutput, name, type, isUpgradePatch); 46 return false; 47 } 48 ShareResPatchInfo.LargeModeInfo largeModeInfo = resPatchInfo.largeModMap.get(name); 49 ResUtil.extractLargeModifyFile(largeZipEntry, largeModeInfo.file, largeModeInfo.crc, out); 50 totalEntryCount++; 51 } 52 53 for (String name : resPatchInfo.addRes) { 54 TinkerZipEntry addZipEntry = newApk.getEntry(name); 55 if (addZipEntry == null) { 56 TinkerLog.w(TAG, "add patch entry is null. path:" + name); 57 manager.getPatchReporter().onPatchTypeExtractFail(patchFile, resOutput, name, type, isUpgradePatch); 58 return false; 59 } 60 ResUtil.extractTinkerEntry(newApk, addZipEntry, out); 61 totalEntryCount++; 62 } 63 64 for (String name : resPatchInfo.modRes) { 65 TinkerZipEntry modZipEntry = newApk.getEntry(name); 66 if (modZipEntry == null) { 67 TinkerLog.w(TAG, "mod patch entry is null. path:" + name); 68 manager.getPatchReporter().onPatchTypeExtractFail(patchFile, resOutput, name, type, isUpgradePatch); 69 return false; 70 } 71 ResUtil.extractTinkerEntry(newApk, modZipEntry, out); 72 totalEntryCount++; 73 } 74 75 //最後對resouces.apk文件進行MD5檢查,判斷是否與resPatchInfo中的MD5一致 76 boolean result = SharePatchFileUtil.checkResourceArscMd5(resOutput, resPatchInfo.resArscMd5);
到此,resources.apk文件生成完畢。
合成好的資源補丁存放在/data/data/${PackageName}/tinker/res/中,名為reosuces.apk。
資源補丁的加載的操作主要放在TinkerResourceLoader.loadTinkerResources函數中,同dex的加載時機一樣,在app啟動時會被調用。直接上源碼,loadTinkerResources會調用monkeyPatchExistingResources執行實際的補丁加載。
1 public static boolean loadTinkerResources(Context context, boolean tinkerLoadVerifyFlag, String directory, Intent intentResult) { 2 if (resPatchInfo == null || resPatchInfo.resArscMd5 == null) { 3 return true; 4 } 5 String resourceString = directory + "/" + RESOURCE_PATH + "/" + RESOURCE_FILE; 6 File resourceFile = new File(resourceString); 7 long start = System.currentTimeMillis(); 8 9 if (tinkerLoadVerifyFlag) { 10 if (!SharePatchFileUtil.checkResourceArscMd5(resourceFile, resPatchInfo.resArscMd5)) { 11 Log.e(TAG, "Failed to load resource file, path: " + resourceFile.getPath() + ", expect md5: " + resPatchInfo.resArscMd5); 12 ShareIntentUtil.setIntentReturnCode(intentResult, ShareConstants.ERROR_LOAD_PATCH_VERSION_RESOURCE_MD5_MISMATCH); 13 return false; 14 } 15 Log.i(TAG, "verify resource file:" + resourceFile.getPath() + " md5, use time: " + (System.currentTimeMillis() - start)); 16 } 17 try { 18 TinkerResourcePatcher.monkeyPatchExistingResources(context, resourceString); 19 Log.i(TAG, "monkeyPatchExistingResources resource file:" + resourceString + ", use time: " + (System.currentTimeMillis() - start)); 20 } catch (Throwable e) { 21 Log.e(TAG, "install resources failed"); 22 //remove patch dex if resource is installed failed 23 try { 24 SystemClassLoaderAdder.uninstallPatchDex(context.getClassLoader()); 25 } catch (Throwable throwable) { 26 Log.e(TAG, "uninstallPatchDex failed", e); 27 } 28 intentResult.putExtra(ShareIntentUtil.INTENT_PATCH_EXCEPTION, e); 29 ShareIntentUtil.setIntentReturnCode(intentResult, ShareConstants.ERROR_LOAD_PATCH_VERSION_RESOURCE_LOAD_EXCEPTION); 30 return false; 31 } 32 33 return true; 34 }
monkeyPatchExistingResources中實現了對外部資源的加載。
1 public static void monkeyPatchExistingResources(Context context, String externalResourceFile) throws Throwable { 2 if (externalResourceFile == null) { 3 return; 4 } 5 // Find the ActivityThread instance for the current thread 6 Class<?> activityThread = Class.forName("android.app.ActivityThread"); 7 Object currentActivityThread = getActivityThread(context, activityThread); 8 9 for (Field field : new Field[]{packagesFiled, resourcePackagesFiled}) { 10 Object value = field.get(currentActivityThread); 11 12 for (Map.Entry<String, WeakReference<?>> entry 13 : ((Map<String, WeakReference<?>>) value).entrySet()) { 14 Object loadedApk = entry.getValue().get(); 15 if (loadedApk == null) { 16 continue; 17 } 18 if (externalResourceFile != null) { 19 resDir.set(loadedApk, externalResourceFile); 20 } 21 } 22 } 23 // Create a new AssetManager instance and point it to the resources installed under 24 // /sdcard 25 // 通過反射調用AssetManager的addAssetPath添加資源路徑 26 if (((Integer) addAssetPathMethod.invoke(newAssetManager, externalResourceFile)) == 0) { 27 throw new IllegalStateException("Could not create new AssetManager"); 28 } 29 30 // Kitkat needs this method call, Lollipop doesn't. However, it doesn't seem to cause any harm 31 // in L, so we do it unconditionally. 32 ensureStringBlocksMethod.invoke(newAssetManager); 33 34 for (WeakReference<Resources> wr : references) { 35 Resources resources = wr.get(); 36 //pre-N 37 if (resources != null) { 38 // Set the AssetManager of the Resources instance to our brand new one 39 try { 40 assetsFiled.set(resources, newAssetManager); 41 } catch (Throwable ignore) { 42 // N 43 Object resourceImpl = resourcesImplFiled.get(resources); 44 // for Huawei HwResourcesImpl 45 Field implAssets = ShareReflectUtil.findField(resourceImpl, "mAssets"); 46 implAssets.setAccessible(true); 47 implAssets.set(resourceImpl, newAssetManager); 48 } 49 50 resources.updateConfiguration(resources.getConfiguration(), resources.getDisplayMetrics()); 51 } 52 } 53 54 // 使用我們的測試資源文件測試是否更新成功 55 if (!checkResUpdate(context)) { 56 throw new TinkerRuntimeException(ShareConstants.CHECK_RES_INSTALL_FAIL); 57 } 58 }
主要原理還是依靠反射,通過AssertManager的addAssetPath函數,加入外部的資源路徑,然後將Resources的mAssets的字段設為前面的AssertManager,這樣在通過getResources去獲取資源的時候就可以獲取到我們外部的資源了。更多具體資源動態替換的原理,可以參考文檔。
轉載請標明本文來源:http://www.cnblogs.com/yyangblog/p/6252490.html
更多內容歡迎star作者的github:https://github.com/LaurenceYang/article
如果發現本文有什麼問題和任何建議,也隨時歡迎交流~
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