編輯:關於android開發
Tinker是微信的第一個開源項目,主要用於安卓應用bug的熱修復和功能的迭代。
Tinker github地址:https://github.com/Tencent/tinker
首先向微信致敬,感謝毫無保留的開源出了這麼一款優秀的熱更新項目。
因Tinker支持Dex,資源文件及so文件的熱更新,本系列將從以下三個方面對Tinker進行源碼解析:
Tinker中Dex的熱更新也主要分為三個部分,本文也將從這三個方面進行分析:
轉載請標明本文來源:http://www.cnblogs.com/yyangblog/p/6249715.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~
當在命令行裡面調用tinkerPatchRelease任務時會調用com.tencent.tinker.build.patch.Runner.tinkerPatch()進行生成補丁生成過程。
1 //gen patch 2 ApkDecoder decoder = new ApkDecoder(config); 3 decoder.onAllPatchesStart(); 4 decoder.patch(config.mOldApkFile, config.mNewApkFile); 5 decoder.onAllPatchesEnd(); 6 7 //gen meta file and version file 8 PatchInfo info = new PatchInfo(config); 9 info.gen(); 10 11 //build patch 12 PatchBuilder builder = new PatchBuilder(config); 13 builder.buildPatch();
ApkDecoder.patch(File oldFile, File newFile)函數中,
會先對manifest文件進行檢測,看其是否有更改,如果發現manifest的組件有新增,則拋出異常,因為目前Tinker暫不支持四大組件的新增。
檢測通過後解壓apk文件,遍歷新舊apk,交給ApkFilesVisitor進行處理。
1 //check manifest change first 2 manifestDecoder.patch(oldFile, newFile); 3 4 unzipApkFiles(oldFile, newFile); 5 6 Files.walkFileTree(mNewApkDir.toPath(), new ApkFilesVisitor(config, mNewApkDir.toPath(), mOldApkDir.toPath(), dexPatchDecoder, soPatchDecoder, resPatchDecoder));
ApkFilesVisitor的visitFile函數中,對於dex類型的文件,調用dexDecoder進行patch操作;
對於so類型的文件,使用soDecoder進行patch操作;
對於Res類型文件,使用resDecoder進行操作。
本文中主要是針對dexDecoder進行分析。
1 public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException { 2 3 Path relativePath = newApkPath.relativize(file); 4 5 Path oldPath = oldApkPath.resolve(relativePath); 6 7 File oldFile = null; 8 //is a new file?! 9 if (oldPath.toFile().exists()) { 10 oldFile = oldPath.toFile(); 11 } 12 String patternKey = relativePath.toString().replace("\\", "/"); 13 14 if (Utils.checkFileInPattern(config.mDexFilePattern, patternKey)) { 15 //also treat duplicate file as unchanged 16 if (Utils.checkFileInPattern(config.mResFilePattern, patternKey) && oldFile != null) { 17 resDuplicateFiles.add(oldFile); 18 } 19 20 try { 21 dexDecoder.patch(oldFile, file.toFile()); 22 } catch (Exception e) { 23 // e.printStackTrace(); 24 throw new RuntimeException(e); 25 } 26 return FileVisitResult.CONTINUE; 27 } 28 if (Utils.checkFileInPattern(config.mSoFilePattern, patternKey)) { 29 //also treat duplicate file as unchanged 30 if (Utils.checkFileInPattern(config.mResFilePattern, patternKey) && oldFile != null) { 31 resDuplicateFiles.add(oldFile); 32 } 33 try { 34 soDecoder.patch(oldFile, file.toFile()); 35 } catch (Exception e) { 36 // e.printStackTrace(); 37 throw new RuntimeException(e); 38 } 39 return FileVisitResult.CONTINUE; 40 } 41 if (Utils.checkFileInPattern(config.mResFilePattern, patternKey)) { 42 try { 43 resDecoder.patch(oldFile, file.toFile()); 44 } catch (Exception e) { 45 // e.printStackTrace(); 46 throw new RuntimeException(e); 47 } 48 return FileVisitResult.CONTINUE; 49 } 50 return FileVisitResult.CONTINUE;
DexDiffDecoder.patch(final File oldFile, final File newFile)
首先檢測輸入的dex文件中是否有不允許修改的類被修改了,如loader相關的類是不允許被修改的,這種情況下會拋出異常;
如果dex是新增的,直接將該dex拷貝到結果文件;
如果dex是修改的,收集增加和刪除的class。oldAndNewDexFilePairList將新舊dex對應關系保存起來,用於後面的分析。
1 excludedClassModifiedChecker.checkIfExcludedClassWasModifiedInNewDex(oldFile, newFile); 2 ... 3 //new add file 4 if (oldFile == null || !oldFile.exists() || oldFile.length() == 0) { 5 hasDexChanged = true; 6 if (!config.mUsePreGeneratedPatchDex) { 7 copyNewDexAndLogToDexMeta(newFile, newMd5, dexDiffOut); 8 return true; 9 } 10 } 11 ... 12 // collect current old dex file and corresponding new dex file for further processing. 13 oldAndNewDexFilePairList.add(new AbstractMap.SimpleEntry<>(oldFile, newFile));
UniqueDexDiffDecoder.patch中將新的dex文件加入到addedDexFiles。
1 public boolean patch(File oldFile, File newFile) throws IOException, TinkerPatchException { 2 boolean added = super.patch(oldFile, newFile); 3 if (added) { 4 String name = newFile.getName(); 5 if (addedDexFiles.contains(name)) { 6 throw new TinkerPatchException("illegal dex name, dex name should be unique, dex:" + name); 7 } else { 8 addedDexFiles.add(name); 9 } 10 } 11 return added; 12 }
在patch完成後,會調用generatePatchInfoFile生成補丁文件。
DexFiffDecoder.generatePatchInfoFile中首先遍歷oldAndNewDexFilePairList,取出新舊文件對。
判斷新舊文件的MD5是否相等,不相等,說明有變化,會根據新舊文件創建DexPatchGenerator,
DexPatchGenerator構造函數中包含了15個Dex區域的比較算法:
DexDiffDecoder.executeAndSaveTo(OutputStream out) 這個函數裡面會根據上面的15個算法對dex的各個區域進行比較,最後生成dex文件的差異,
這是整個dex diff算法的核心。以StringDataSectionDiffAlgorithm為例,算法流程如下:
--------------------------------------------
獲取oldDex中StringData區域的Item,並進行排序
獲取newDex中StringData區域的Item,並進行排序
然後對ITEM依次比較
<0
說明從老的dex中刪除了該String,patchOperationList中添加Del操作
\>0
說明添加了該String,patchOperationList添加add操作
=0
說明都有該String, 記錄oldIndexToNewIndexMap,oldOffsetToNewOffsetMap
old item已到結尾
剩下的item說明都是新增項,patchOperationList添加add操作
new item已到結尾
剩下的item說明都是刪除項,patchOperationList添加del操作
最後對對patchOperationList進行優化(
{OP_DEL idx} followed by {OP_ADD the_same_idx newItem} will be replaced by {OP_REPLACE idx newItem})
--------------------------------------------
Dexdiff得到的最終生成產物就是針對原dex的一個操作序列。
關於DexDiff算法,更加詳細的介紹可以參考https://www.zybuluo.com/dodola/note/554061,算法名曰二路歸並。
對每個區域比較後會將比較的結果寫入文件中,文件格式寫在DexDataBuffer中
1 private void writeResultToStream(OutputStream os) throws IOException { 2 DexDataBuffer buffer = new DexDataBuffer(); 3 buffer.write(DexPatchFile.MAGIC); 4 buffer.writeShort(DexPatchFile.CURRENT_VERSION); 5 buffer.writeInt(this.patchedDexSize); 6 // we will return here to write firstChunkOffset later. 7 int posOfFirstChunkOffsetField = buffer.position(); 8 buffer.writeInt(0); 9 buffer.writeInt(this.patchedStringIdsOffset); 10 buffer.writeInt(this.patchedTypeIdsOffset); 11 buffer.writeInt(this.patchedProtoIdsOffset); 12 buffer.writeInt(this.patchedFieldIdsOffset); 13 buffer.writeInt(this.patchedMethodIdsOffset); 14 buffer.writeInt(this.patchedClassDefsOffset); 15 buffer.writeInt(this.patchedMapListOffset); 16 buffer.writeInt(this.patchedTypeListsOffset); 17 buffer.writeInt(this.patchedAnnotationSetRefListItemsOffset); 18 buffer.writeInt(this.patchedAnnotationSetItemsOffset); 19 buffer.writeInt(this.patchedClassDataItemsOffset); 20 buffer.writeInt(this.patchedCodeItemsOffset); 21 buffer.writeInt(this.patchedStringDataItemsOffset); 22 buffer.writeInt(this.patchedDebugInfoItemsOffset); 23 buffer.writeInt(this.patchedAnnotationItemsOffset); 24 buffer.writeInt(this.patchedEncodedArrayItemsOffset); 25 buffer.writeInt(this.patchedAnnotationsDirectoryItemsOffset); 26 buffer.write(this.oldDex.computeSignature(false)); 27 int firstChunkOffset = buffer.position(); 28 buffer.position(posOfFirstChunkOffsetField); 29 buffer.writeInt(firstChunkOffset); 30 buffer.position(firstChunkOffset); 31 32 writePatchOperations(buffer, this.stringDataSectionDiffAlg.getPatchOperationList()); 33 writePatchOperations(buffer, this.typeIdSectionDiffAlg.getPatchOperationList()); 34 writePatchOperations(buffer, this.typeListSectionDiffAlg.getPatchOperationList()); 35 writePatchOperations(buffer, this.protoIdSectionDiffAlg.getPatchOperationList()); 36 writePatchOperations(buffer, this.fieldIdSectionDiffAlg.getPatchOperationList()); 37 writePatchOperations(buffer, this.methodIdSectionDiffAlg.getPatchOperationList()); 38 writePatchOperations(buffer, this.annotationSectionDiffAlg.getPatchOperationList()); 39 writePatchOperations(buffer, this.annotationSetSectionDiffAlg.getPatchOperationList()); 40 writePatchOperations(buffer, this.annotationSetRefListSectionDiffAlg.getPatchOperationList()); 41 writePatchOperations(buffer, this.annotationsDirectorySectionDiffAlg.getPatchOperationList()); 42 writePatchOperations(buffer, this.debugInfoSectionDiffAlg.getPatchOperationList()); 43 writePatchOperations(buffer, this.codeSectionDiffAlg.getPatchOperationList()); 44 writePatchOperations(buffer, this.classDataSectionDiffAlg.getPatchOperationList()); 45 writePatchOperations(buffer, this.encodedArraySectionDiffAlg.getPatchOperationList()); 46 writePatchOperations(buffer, this.classDefSectionDiffAlg.getPatchOperationList()); 47 48 byte[] bufferData = buffer.array(); 49 os.write(bufferData); 50 os.flush(); 51 }
生成的文件以dex結尾,但需要注意的是,它不是真正的dex文件,其格式可參考DexDataBuffer類。
當app收到服務器下發的補丁後,會觸發DefaultPatchListener.onPatchReceived事件,
調用TinkerPatchService.runPatchService啟動patch進程進行補丁patch工作。
UpgradePatch.tryPatch()中會首先檢查補丁的合法性,簽名,以及是否安裝過補丁,檢查通過後會嘗試dex,so以及res文件的patch。
本文中主要分析DexDiffPatchInternal.tryRecoverDexFiles,討論dex的patch過程。
1 DexDiffPatchInternal.tryRecoverDexFiles 2 BsDiffPatchInternal.tryRecoverLibraryFiles 3 ResDiffPatchInternal.tryRecoverResourceFiles 4 rewritePatchInfoFileWithLock
tryRecoverDexFiles調用DexDiffPatchInternal.patchDexFile,
最終通過DexPatchApplier.executeAndSaveTo進行執行及生產全量dex。
1 private static void patchDexFile( 2 ZipFile baseApk, ZipFile patchPkg, ZipEntry oldDexEntry, ZipEntry patchFileEntry, 3 ShareDexDiffPatchInfo patchInfo, File patchedDexFile) throws IOException { 4 InputStream oldDexStream = null; 5 InputStream patchFileStream = null; 6 try { 7 oldDexStream = baseApk.getInputStream(oldDexEntry); 8 patchFileStream = (patchFileEntry != null ? patchPkg.getInputStream(patchFileEntry) : null); 9 10 final boolean isRawDexFile = SharePatchFileUtil.isRawDexFile(patchInfo.rawName); 11 if (!isRawDexFile || patchInfo.isJarMode) { 12 ZipOutputStream zos = null; 13 try { 14 zos = new ZipOutputStream(new BufferedOutputStream(new FileOutputStream(patchedDexFile))); 15 zos.putNextEntry(new ZipEntry(ShareConstants.DEX_IN_JAR)); 16 // Old dex is not a raw dex file. 17 if (!isRawDexFile) { 18 ZipInputStream zis = null; 19 try { 20 zis = new ZipInputStream(oldDexStream); 21 ZipEntry entry; 22 while ((entry = zis.getNextEntry()) != null) { 23 if (ShareConstants.DEX_IN_JAR.equals(entry.getName())) break; 24 } 25 if (entry == null) { 26 throw new TinkerRuntimeException("can't recognize zip dex format file:" + patchedDexFile.getAbsolutePath()); 27 } 28 new DexPatchApplier(zis, (int) entry.getSize(), patchFileStream).executeAndSaveTo(zos); 29 } finally { 30 SharePatchFileUtil.closeQuietly(zis); 31 } 32 } else { 33 new DexPatchApplier(oldDexStream, (int) oldDexEntry.getSize(), patchFileStream).executeAndSaveTo(zos); 34 } 35 zos.closeEntry(); 36 } finally { 37 SharePatchFileUtil.closeQuietly(zos); 38 } 39 } else { 40 new DexPatchApplier(oldDexStream, (int) oldDexEntry.getSize(), patchFileStream).executeAndSaveTo(patchedDexFile); 41 } 42 } finally { 43 SharePatchFileUtil.closeQuietly(oldDexStream); 44 SharePatchFileUtil.closeQuietly(patchFileStream); 45 } 46 }
DexPatchApplier.executeAndSaveTo(OutputStream out)中會對15個dex區域進行patch操作,
針對old dex和patch dex進行合並,生成全量dex文件。
1 public void executeAndSaveTo(OutputStream out) throws IOException { 2 // Before executing, we should check if this patch can be applied to 3 // old dex we passed in. 4 // 首先old apk的簽名和patchfile所攜帶的old apk簽名是否一致,不一致則拋出異常 5 byte[] oldDexSign = this.oldDex.computeSignature(false); 6 if (oldDexSign == null) { 7 throw new IOException("failed to compute old dex's signature."); 8 } 9 10 if (this.patchFile != null) { 11 byte[] oldDexSignInPatchFile = this.patchFile.getOldDexSignature(); 12 if (CompareUtils.uArrCompare(oldDexSign, oldDexSignInPatchFile) != 0) { 13 throw new IOException( 14 String.format( 15 "old dex signature mismatch! expected: %s, actual: %s", 16 Arrays.toString(oldDexSign), 17 Arrays.toString(oldDexSignInPatchFile) 18 ) 19 ); 20 } 21 } 22 23 String oldDexSignStr = Hex.toHexString(oldDexSign); 24 25 // Firstly, set sections' offset after patched, sort according to their offset so that 26 // the dex lib of aosp can calculate section size. 27 // patchedDex是最終合成的dex,首先設定各個區域的偏移量 28 TableOfContents patchedToc = this.patchedDex.getTableOfContents(); 29 30 patchedToc.header.off = 0; 31 patchedToc.header.size = 1; 32 patchedToc.mapList.size = 1; 33 34 if (extraInfoFile == null || !extraInfoFile.isAffectedOldDex(this.oldDexSignStr)) { 35 patchedToc.stringIds.off 36 = this.patchFile.getPatchedStringIdSectionOffset(); 37 patchedToc.typeIds.off 38 = this.patchFile.getPatchedTypeIdSectionOffset(); 39 patchedToc.typeLists.off 40 = this.patchFile.getPatchedTypeListSectionOffset(); 41 patchedToc.protoIds.off 42 = this.patchFile.getPatchedProtoIdSectionOffset(); 43 patchedToc.fieldIds.off 44 = this.patchFile.getPatchedFieldIdSectionOffset(); 45 patchedToc.methodIds.off 46 = this.patchFile.getPatchedMethodIdSectionOffset(); 47 patchedToc.classDefs.off 48 = this.patchFile.getPatchedClassDefSectionOffset(); 49 patchedToc.mapList.off 50 = this.patchFile.getPatchedMapListSectionOffset(); 51 patchedToc.stringDatas.off 52 = this.patchFile.getPatchedStringDataSectionOffset(); 53 patchedToc.annotations.off 54 = this.patchFile.getPatchedAnnotationSectionOffset(); 55 patchedToc.annotationSets.off 56 = this.patchFile.getPatchedAnnotationSetSectionOffset(); 57 patchedToc.annotationSetRefLists.off 58 = this.patchFile.getPatchedAnnotationSetRefListSectionOffset(); 59 patchedToc.annotationsDirectories.off 60 = this.patchFile.getPatchedAnnotationsDirectorySectionOffset(); 61 patchedToc.encodedArrays.off 62 = this.patchFile.getPatchedEncodedArraySectionOffset(); 63 patchedToc.debugInfos.off 64 = this.patchFile.getPatchedDebugInfoSectionOffset(); 65 patchedToc.codes.off 66 = this.patchFile.getPatchedCodeSectionOffset(); 67 patchedToc.classDatas.off 68 = this.patchFile.getPatchedClassDataSectionOffset(); 69 patchedToc.fileSize 70 = this.patchFile.getPatchedDexSize(); 71 } else { 72 ... 73 } 74 75 Arrays.sort(patchedToc.sections); 76 77 patchedToc.computeSizesFromOffsets(); 78 79 // Secondly, run patch algorithms according to sections' dependencies. 80 // 對每個區域進行patch操作 81 this.stringDataSectionPatchAlg = new StringDataSectionPatchAlgorithm( 82 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 83 patchedToSmallPatchedIndexMap, extraInfoFile 84 ); 85 this.typeIdSectionPatchAlg = new TypeIdSectionPatchAlgorithm( 86 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 87 patchedToSmallPatchedIndexMap, extraInfoFile 88 ); 89 this.protoIdSectionPatchAlg = new ProtoIdSectionPatchAlgorithm( 90 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 91 patchedToSmallPatchedIndexMap, extraInfoFile 92 ); 93 this.fieldIdSectionPatchAlg = new FieldIdSectionPatchAlgorithm( 94 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 95 patchedToSmallPatchedIndexMap, extraInfoFile 96 ); 97 this.methodIdSectionPatchAlg = new MethodIdSectionPatchAlgorithm( 98 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 99 patchedToSmallPatchedIndexMap, extraInfoFile 100 ); 101 this.classDefSectionPatchAlg = new ClassDefSectionPatchAlgorithm( 102 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 103 patchedToSmallPatchedIndexMap, extraInfoFile 104 ); 105 this.typeListSectionPatchAlg = new TypeListSectionPatchAlgorithm( 106 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 107 patchedToSmallPatchedIndexMap, extraInfoFile 108 ); 109 this.annotationSetRefListSectionPatchAlg = new AnnotationSetRefListSectionPatchAlgorithm( 110 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 111 patchedToSmallPatchedIndexMap, extraInfoFile 112 ); 113 this.annotationSetSectionPatchAlg = new AnnotationSetSectionPatchAlgorithm( 114 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 115 patchedToSmallPatchedIndexMap, extraInfoFile 116 ); 117 this.classDataSectionPatchAlg = new ClassDataSectionPatchAlgorithm( 118 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 119 patchedToSmallPatchedIndexMap, extraInfoFile 120 ); 121 this.codeSectionPatchAlg = new CodeSectionPatchAlgorithm( 122 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 123 patchedToSmallPatchedIndexMap, extraInfoFile 124 ); 125 this.debugInfoSectionPatchAlg = new DebugInfoItemSectionPatchAlgorithm( 126 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 127 patchedToSmallPatchedIndexMap, extraInfoFile 128 ); 129 this.annotationSectionPatchAlg = new AnnotationSectionPatchAlgorithm( 130 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 131 patchedToSmallPatchedIndexMap, extraInfoFile 132 ); 133 this.encodedArraySectionPatchAlg = new StaticValueSectionPatchAlgorithm( 134 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 135 patchedToSmallPatchedIndexMap, extraInfoFile 136 ); 137 this.annotationsDirectorySectionPatchAlg = new AnnotationsDirectorySectionPatchAlgorithm( 138 patchFile, oldDex, patchedDex, oldToFullPatchedIndexMap, 139 patchedToSmallPatchedIndexMap, extraInfoFile 140 ); 141 142 this.stringDataSectionPatchAlg.execute(); 143 this.typeIdSectionPatchAlg.execute(); 144 this.typeListSectionPatchAlg.execute(); 145 this.protoIdSectionPatchAlg.execute(); 146 this.fieldIdSectionPatchAlg.execute(); 147 this.methodIdSectionPatchAlg.execute(); 148 Runtime.getRuntime().gc(); 149 this.annotationSectionPatchAlg.execute(); 150 this.annotationSetSectionPatchAlg.execute(); 151 this.annotationSetRefListSectionPatchAlg.execute(); 152 this.annotationsDirectorySectionPatchAlg.execute(); 153 Runtime.getRuntime().gc(); 154 this.debugInfoSectionPatchAlg.execute(); 155 this.codeSectionPatchAlg.execute(); 156 Runtime.getRuntime().gc(); 157 this.classDataSectionPatchAlg.execute(); 158 this.encodedArraySectionPatchAlg.execute(); 159 this.classDefSectionPatchAlg.execute(); 160 Runtime.getRuntime().gc(); 161 162 // Thirdly, write header, mapList. Calculate and write patched dex's sign and checksum. 163 Dex.Section headerOut = this.patchedDex.openSection(patchedToc.header.off); 164 patchedToc.writeHeader(headerOut); 165 166 Dex.Section mapListOut = this.patchedDex.openSection(patchedToc.mapList.off); 167 patchedToc.writeMap(mapListOut); 168 169 this.patchedDex.writeHashes(); 170 171 // Finally, write patched dex to file. 172 this.patchedDex.writeTo(out);
每個區域的合並算法采用二路歸並,在old dex的基礎上對元素進行刪除,增加,替換操作。
這裡的算法和生成補丁的DexDiff是一個逆向的過程。
1 private void doFullPatch( 2 Dex.Section oldSection, 3 int oldItemCount, 4 int[] deletedIndices, 5 int[] addedIndices, 6 int[] replacedIndices 7 ) { 8 int deletedItemCount = deletedIndices.length; 9 int addedItemCount = addedIndices.length; 10 int replacedItemCount = replacedIndices.length; 11 int newItemCount = oldItemCount + addedItemCount - deletedItemCount; 12 13 int deletedItemCounter = 0; 14 int addActionCursor = 0; 15 int replaceActionCursor = 0; 16 17 int oldIndex = 0; 18 int patchedIndex = 0; 19 while (oldIndex < oldItemCount || patchedIndex < newItemCount) { 20 if (addActionCursor < addedItemCount && addedIndices[addActionCursor] == patchedIndex) { 21 T addedItem = nextItem(patchFile.getBuffer()); 22 int patchedOffset = writePatchedItem(addedItem); 23 ++addActionCursor; 24 ++patchedIndex; 25 } else 26 if (replaceActionCursor < replacedItemCount && replacedIndices[replaceActionCursor] == patchedIndex) { 27 T replacedItem = nextItem(patchFile.getBuffer()); 28 int patchedOffset = writePatchedItem(replacedItem); 29 ++replaceActionCursor; 30 ++patchedIndex; 31 } else 32 if (Arrays.binarySearch(deletedIndices, oldIndex) >= 0) { 33 T skippedOldItem = nextItem(oldSection); // skip old item. 34 markDeletedIndexOrOffset( 35 oldToFullPatchedIndexMap, 36 oldIndex, 37 getItemOffsetOrIndex(oldIndex, skippedOldItem) 38 ); 39 ++oldIndex; 40 ++deletedItemCounter; 41 } else 42 if (Arrays.binarySearch(replacedIndices, oldIndex) >= 0) { 43 T skippedOldItem = nextItem(oldSection); // skip old item. 44 markDeletedIndexOrOffset( 45 oldToFullPatchedIndexMap, 46 oldIndex, 47 getItemOffsetOrIndex(oldIndex, skippedOldItem) 48 ); 49 ++oldIndex; 50 } else 51 if (oldIndex < oldItemCount) { 52 T oldItem = adjustItem(this.oldToFullPatchedIndexMap, nextItem(oldSection)); 53 54 int patchedOffset = writePatchedItem(oldItem); 55 56 updateIndexOrOffset( 57 this.oldToFullPatchedIndexMap, 58 oldIndex, 59 getItemOffsetOrIndex(oldIndex, oldItem), 60 patchedIndex, 61 patchedOffset 62 ); 63 64 ++oldIndex; 65 ++patchedIndex; 66 } 67 } 68 69 if (addActionCursor != addedItemCount || deletedItemCounter != deletedItemCount 70 || replaceActionCursor != replacedItemCount 71 ) { 72 throw new IllegalStateException( 73 String.format( 74 "bad patch operation sequence. addCounter: %d, addCount: %d, " 75 + "delCounter: %d, delCount: %d, " 76 + "replaceCounter: %d, replaceCount:%d", 77 addActionCursor, 78 addedItemCount, 79 deletedItemCounter, 80 deletedItemCount, 81 replaceActionCursor, 82 replacedItemCount 83 ) 84 ); 85 } 86 }
在extractDexDiffInternals調用完以後,
會調用TinkerParallelDexOptimizer.optimizeAll對生成的全量dex進行optimize操作,生成odex文件。
最終合成的文件會放到/data/data/${package_name}/tinker目錄下。
到此,生成Dex過程完成。
TinkerApplication通過反射的方式將實際的app業務隔離,這樣可以在熱更新的時候修改實際的app內容。
在TinkerApplication中的onBaseContextAttached中會通過反射調用TinkerLoader的tryLoad加載已經合成的dex。
1 private static final String TINKER_LOADER_METHOD = "tryLoad"; 2 private void loadTinker() { 3 //disable tinker, not need to install 4 if (tinkerFlags == TINKER_DISABLE) { 5 return; 6 } 7 tinkerResultIntent = new Intent(); 8 try { 9 //reflect tinker loader, because loaderClass may be define by user! 10 Class<?> tinkerLoadClass = Class.forName(loaderClassName, false, getClassLoader()); 11 12 Method loadMethod = tinkerLoadClass.getMethod(TINKER_LOADER_METHOD, TinkerApplication.class, int.class, boolean.class); 13 Constructor<?> constructor = tinkerLoadClass.getConstructor(); 14 tinkerResultIntent = (Intent) loadMethod.invoke(constructor.newInstance(), this, tinkerFlags, tinkerLoadVerifyFlag); 15 } catch (Throwable e) { 16 //has exception, put exception error code 17 ShareIntentUtil.setIntentReturnCode(tinkerResultIntent, ShareConstants.ERROR_LOAD_PATCH_UNKNOWN_EXCEPTION); 18 tinkerResultIntent.putExtra(INTENT_PATCH_EXCEPTION, e); 19 } 20 }
tryLoadPatchFilesInternal是加載Patch文件的核心函數,主要做了以下的事情:
TinkerDexLoader.loadTinkerJars處理加載dex文件。
1 // 獲取PatchClassLoader 2 PathClassLoader classLoader = (PathClassLoader) TinkerDexLoader.class.getClassLoader(); 3 4 ... 5 // 生產合法文件列表 6 ArrayList<File> legalFiles = new ArrayList<>(); 7 8 final boolean isArtPlatForm = ShareTinkerInternals.isVmArt(); 9 for (ShareDexDiffPatchInfo info : dexList) { 10 //for dalvik, ignore art support dex 11 // dalvik虛擬機中,忽略掉只支持art的dex 12 if (isJustArtSupportDex(info)) { 13 continue; 14 } 15 String path = dexPath + info.realName; 16 File file = new File(path); 17 18 if (tinkerLoadVerifyFlag) { 19 long start = System.currentTimeMillis(); 20 String checkMd5 = isArtPlatForm ? info.destMd5InArt : info.destMd5InDvm; 21 if (!SharePatchFileUtil.verifyDexFileMd5(file, checkMd5)) { 22 //it is good to delete the mismatch file 23 ShareIntentUtil.setIntentReturnCode(intentResult, ShareConstants.ERROR_LOAD_PATCH_VERSION_DEX_MD5_MISMATCH); 24 intentResult.putExtra(ShareIntentUtil.INTENT_PATCH_MISMATCH_DEX_PATH, 25 file.getAbsolutePath()); 26 return false; 27 } 28 Log.i(TAG, "verify dex file:" + file.getPath() + " md5, use time: " + (System.currentTimeMillis() - start)); 29 } 30 legalFiles.add(file); 31 } 32 33 // 如果系統OTA,對這些合法dex進行優化 34 if (isSystemOTA) { 35 parallelOTAResult = true; 36 parallelOTAThrowable = null; 37 Log.w(TAG, "systemOTA, try parallel oat dexes!!!!!"); 38 39 TinkerParallelDexOptimizer.optimizeAll( 40 legalFiles, optimizeDir, 41 new TinkerParallelDexOptimizer.ResultCallback() { 42 @Override 43 public void onSuccess(File dexFile, File optimizedDir) { 44 // Do nothing. 45 } 46 @Override 47 public void onFailed(File dexFile, File optimizedDir, Throwable thr) { 48 parallelOTAResult = false; 49 parallelOTAThrowable = thr; 50 } 51 } 52 ); 53 if (!parallelOTAResult) { 54 Log.e(TAG, "parallel oat dexes failed"); 55 intentResult.putExtra(ShareIntentUtil.INTENT_PATCH_EXCEPTION, parallelOTAThrowable); 56 ShareIntentUtil.setIntentReturnCode(intentResult, ShareConstants.ERROR_LOAD_PATCH_VERSION_PARALLEL_DEX_OPT_EXCEPTION); 57 return false; 58 } 59 } 60 61 // 加載Dex 62 SystemClassLoaderAdder.installDexes(application, classLoader, optimizeDir, legalFiles);
SystemClassLoaderAdder.installDexes中按照安卓的版本對dex進行install,這裡應該是借鑒了MultiDex裡面的install做法。
另外Tinker在生成補丁階段會生成一個test.dex,這個test.dex的作用就是用來驗證dex的加載是否成功。
test.dex中含有com.tencent.tinker.loader.TinkerTestDexLoad類,該類中包含一個字段isPatch,checkDexInstall就是通過findField該字段判斷是否加載成功。
1 public static void installDexes(Application application, PathClassLoader loader, File dexOptDir, List<File> files) throws Throwable { 2 if (!files.isEmpty()) { 3 ClassLoader classLoader = loader; 4 if (Build.VERSION.SDK_INT >= 24) { 5 classLoader = AndroidNClassLoader.inject(loader, application); 6 } 7 //because in dalvik, if inner class is not the same classloader with it wrapper class. 8 //it won't fail at dex2opt 9 if (Build.VERSION.SDK_INT >= 23) { 10 V23.install(classLoader, files, dexOptDir); 11 } else if (Build.VERSION.SDK_INT >= 19) { 12 V19.install(classLoader, files, dexOptDir); 13 } else if (Build.VERSION.SDK_INT >= 14) { 14 V14.install(classLoader, files, dexOptDir); 15 } else { 16 V4.install(classLoader, files, dexOptDir); 17 } 18 //install done 19 sPatchDexCount = files.size(); 20 21 // Tinker在生成補丁階段會生成一個test.dex,這個test.dex的作用就是用來驗證dex的加載是否成功。test.dex中含有com.tencent.tinker.loader.TinkerTestDexLoad類,該類中包含一個字段isPatch,checkDexInstall就是通過findField該字段判斷是否加載成功。 22 if (!checkDexInstall(classLoader)) { 23 //reset patch dex 24 SystemClassLoaderAdder.uninstallPatchDex(classLoader); 25 throw new TinkerRuntimeException(ShareConstants.CHECK_DEX_INSTALL_FAIL); 26 } 27 } 28 }
------分割線-----
在講install具體細節之前,回顧一下具體原理。關於Android的ClassLoader體系,android中加載類一般使用的是PathClassLoader和DexClassLoader
PathClassLoader,源碼注釋可以看出,android使用這個類作為系統類和應用類的加載器。
/** * Provides a simple {@link ClassLoader} implementation that operates on a list * of files and directories in the local file system, but does not attempt to * load classes from the network. Android uses this class for its system class * loader and for its application class loader(s). */
DexClassLoader,源碼注釋可以看出,可以用來從.jar和.apk類型的文件內部加載classes.dex文件。
/** * A class loader that loads classes from {@code .jar} and {@code .apk} files * containing a {@code classes.dex} entry. This can be used to execute code not * installed as part of an application. * * <p>This class loader requires an application-private, writable directory to * cache optimized classes. Use {@code Context.getDir(String, int)} to create * such a directory: <pre> {@code * File dexOutputDir = context.getDir("dex", 0); * }</pre> * * <p><strong>Do not cache optimized classes on external storage.</strong> * External storage does not provide access controls necessary to protect your * application from code injection attacks. */
ok,到這裡,大家只需要明白,Android使用PathClassLoader作為其類加載器,DexClassLoader可以從.jar和.apk類型的文件內部加載classes.dex文件就好了。
PathClassLoader和DexClassLoader都繼承自BaseDexClassLoader。在BaseDexClassLoader中有如下源碼:
##BaseDexClassLoader.java## /** structured lists of path elements */ private final DexPathList pathList; @Override protected Class<?> findClass(String name) throws ClassNotFoundException { Class clazz = pathList.findClass(name); if (clazz == null) { throw new ClassNotFoundException(name); } return clazz; } ##DexPathList.java## /** list of dex/resource (class path) elements */ private final Element[] dexElements; public Class findClass(String name) { for (Element element : dexElements) { DexFile dex = element.dexFile; if (dex != null) { Class clazz = dex.loadClassBinaryName(name, definingContext); if (clazz != null) { return clazz; } } } return null; } ##DexFile.java## public Class loadClassBinaryName(String name, ClassLoader loader) { return defineClass(name, loader, mCookie); } private native static Class defineClass(String name, ClassLoader loader, int cookie);
通俗點講:
一個ClassLoader可以包含多個dex文件,每個dex文件是一個Element,多個dex文件排列成一個有序的數組dexElements,當找類的時候,會按順序遍歷dex文件,然後從當前遍歷的dex文件中找類,如果找類則返回,如果找不到從下一個dex文件繼續查找。(來自:安卓App熱補丁動態修復技術介紹)
回到分割線以前:
install的做法就是,先獲取BaseDexClassLoader的dexPathList對象,
然後通過dexPathList的makeDexElements函數將我們要安裝的dex轉化成Element[]對象,
最後將其和dexPathList的dexElements對象進行合並,就是新的Element[]對象,
因為我們添加的dex都被放在dexElements數組的最前面,所以當通過findClass來查找這個類時,就是使用的我們最新的dex裡面的類。
以V19的install為例,下面的代碼非常清晰的描述了實際的加載所做的事情:
1 private static final class V19 { 2 private static void install(ClassLoader loader, List<File> additionalClassPathEntries, 3 File optimizedDirectory) 4 throws IllegalArgumentException, IllegalAccessException, 5 NoSuchFieldException, InvocationTargetException, NoSuchMethodException, IOException { 6 /* The patched class loader is expected to be a descendant of 7 * dalvik.system.BaseDexClassLoader. We modify its 8 * dalvik.system.DexPathList pathList field to append additional DEX 9 * file entries. 10 */ 11 Field pathListField = ShareReflectUtil.findField(loader, "pathList"); 12 Object dexPathList = pathListField.get(loader); 13 ArrayList<IOException> suppressedExceptions = new ArrayList<IOException>(); 14 ShareReflectUtil.expandFieldArray(dexPathList, "dexElements", makeDexElements(dexPathList, 15 new ArrayList<File>(additionalClassPathEntries), optimizedDirectory, 16 suppressedExceptions)); 17 if (suppressedExceptions.size() > 0) { 18 for (IOException e : suppressedExceptions) { 19 Log.w(TAG, "Exception in makeDexElement", e); 20 throw e; 21 } 22 } 23 } 24 }
因為android版本更新較快,不同版本裡面的DexPathList等類的函數和字段都有一些變化,這也是在install的時候需要對不同版本進行適配的原因。
到此,在當前app的classloader裡面就包含了我們第二步驟裡面合成的全量DEX,我們在加載類的時候就能用到新的內容了。
Congratulations!!Dex的加載流程完成。
轉載請標明本文來源:http://www.cnblogs.com/yyangblog/p/6249715.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~
下一篇文章我們將對Tinker中對資源文件的熱更新進行分析。
EditText在API中的結構 java.lang.Object android.view.View android.widget.Text
ListView的CheckBox實現全部選中/不選中,listviewcheckbox在Adapter類中定義一個HashMap列表,保存每一行是否被選中: priv
Java 單例模式,Java模式前言:昨天公司計劃把項目中的部分功能做出SDK的形式,供其他公司的產品使用,所以不得不重新研究一下單例模式。 為什麼單例 1
Android數據庫相關整理,android數據庫整理今天對Android中數據庫相關的操作和代碼做了一個整理,便於自己之後的查閱。主要內容有: 1.原生數據庫寫法 2.