将APK解析时间优化到原先的三分之一

重写apk parser，移除了大量不必要的计算，将～70M的APK解析时间从1500～1700ms降低到大约500ms。

Author: Em3rs0n

build.gradle

@@ -19,12 +19,6 @@ apply plugin: 'com.android.library'
 apply plugin: 'kotlin-android'
 apply plugin: 'org.jetbrains.dokka-android'
 
-kotlin {
-    experimental {
-        coroutines "enable"
-    }
-}
-
 android {
     compileSdkVersion 28
     defaultConfig {

src/androidTest/kotlin/com/gh0u1l5/wechatmagician/spellbook/MirrorUnitTest.kt

@@ -8,18 +8,20 @@ import com.gh0u1l5.wechatmagician.spellbook.base.Version
 import com.gh0u1l5.wechatmagician.spellbook.mirror.MirrorClasses
 import com.gh0u1l5.wechatmagician.spellbook.mirror.MirrorFields
 import com.gh0u1l5.wechatmagician.spellbook.mirror.MirrorMethods
+import com.gh0u1l5.wechatmagician.spellbook.parser.ApkFile
 import com.gh0u1l5.wechatmagician.spellbook.util.FileUtil
 import com.gh0u1l5.wechatmagician.spellbook.util.MirrorUtil
 import com.gh0u1l5.wechatmagician.spellbook.util.ReflectionUtil
 import dalvik.system.PathClassLoader
-import net.dongliu.apk.parser.ApkFile
 import org.junit.Assert.*
 import org.junit.Before
 import org.junit.Test
 import org.junit.runner.RunWith
 import java.io.File
 import java.lang.ClassLoader.getSystemClassLoader
+import kotlin.system.measureTimeMillis
 
+@ExperimentalUnsignedTypes
 @RunWith(AndroidJUnit4::class)
 class MirrorUnitTest {
     companion object {
@@ -34,8 +36,13 @@ class MirrorUnitTest {
     }
 
     private fun verifyPackage(apkPath: String) {
-        val cacheDir = context!!.cacheDir
+        // Parse the version of the apk
+        val regex = Regex("wechat-v(.*)\\.apk")
+        val match = regex.find(apkPath) ?: throw Exception("Unexpected path format")
+        val version = match.groupValues[1]
 
+        // Store APK file to cache directory.
+        val cacheDir = context!!.cacheDir
         val apkFile = File(cacheDir, apkPath)
         try {
             javaClass.classLoader!!.getResourceAsStream(apkPath).use {
@@ -46,25 +53,36 @@ class MirrorUnitTest {
             return // ignore if the apk isn't accessible
         }
 
+        // Ensure the apk is presented, and start the test
         assertTrue(apkFile.exists())
         ApkFile(apkFile).use {
+            // Benchmark the APK parser
+            val timeParseDex = measureTimeMillis { it.classTypes }
+            Log.d("MirrorUnitTest", "Benchmark: Parse DexClasses takes $timeParseDex ms.")
+
+            // Initialize WechatGlobal
             WechatGlobal.wxUnitTestMode = true
-            WechatGlobal.wxVersion = Version(it.apkMeta.versionName)
-            WechatGlobal.wxPackageName = it.apkMeta.packageName
+            WechatGlobal.wxVersion = Version(version)
+            WechatGlobal.wxPackageName = "com.tencent.mm"
             WechatGlobal.wxLoader = PathClassLoader(apkFile.absolutePath, getSystemClassLoader())
-            WechatGlobal.wxClasses = it.dexClasses.map { clazz ->
-                ReflectionUtil.ClassName(clazz.classType)
-            }
+            WechatGlobal.wxClasses = it.classTypes
 
+            // Clear cached lazy evaluations
             val objects = MirrorClasses + MirrorMethods + MirrorFields
             ReflectionUtil.clearClassCache()
             ReflectionUtil.clearMethodCache()
             objects.forEach { instance ->
                 MirrorUtil.clearUnitTestLazyFields(instance)
             }
 
-            MirrorUtil.generateReportWithForceEval(objects).forEach {
-                Log.d("MirrorUnitTest", "Verified ${it.first} -> ${it.second}")
+            // Test each lazy evaluation and generate result.
+            var result: List<Pair<String, String>>? = null
+            val timeSearch = measureTimeMillis {
+                result = MirrorUtil.generateReportWithForceEval(objects)
+            }
+            Log.d("MirrorUnitTest", "Benchmark: Search over classes takes $timeSearch ms.")
+            result?.forEach { entry ->
+                Log.d("MirrorUnitTest", "Verified: ${entry.first} -> ${entry.second}")
             }
         }
 

src/main/kotlin/com/gh0u1l5/wechatmagician/spellbook/WechatGlobal.kt

@@ -5,9 +5,9 @@ import android.widget.BaseAdapter
 import com.gh0u1l5.wechatmagician.spellbook.SpellBook.getApplicationVersion
 import com.gh0u1l5.wechatmagician.spellbook.base.Version
 import com.gh0u1l5.wechatmagician.spellbook.base.WaitChannel
+import com.gh0u1l5.wechatmagician.spellbook.parser.ApkFile
 import com.gh0u1l5.wechatmagician.spellbook.util.BasicUtil.tryAsynchronously
 import de.robv.android.xposed.callbacks.XC_LoadPackage
-import net.dongliu.apk.parser.ApkFile
 import java.lang.ref.WeakReference
 
 /**
@@ -38,7 +38,7 @@ object WechatGlobal {
      *
      * Example: "Ljava/lang/String;"
      */
-    @Volatile var wxClasses: List<String>? = null
+    @Volatile var wxClasses: Array<String>? = null
 
     /**
      * A flag indicating whether the codes are running under unit test mode.
@@ -114,7 +114,7 @@ object WechatGlobal {
                 wxLoader = lpparam.classLoader
 
                 ApkFile(lpparam.appInfo.sourceDir).use {
-                    wxClasses = it.dexClasses.map { it.classType }
+                    wxClasses = it.classTypes
                 }
             } finally {
                 initializeChannel.done()

src/main/kotlin/com/gh0u1l5/wechatmagician/spellbook/parser/ApkFile.kt

@@ -0,0 +1,36 @@
+package com.gh0u1l5.wechatmagician.spellbook.parser
+
+import java.io.Closeable
+import java.io.File
+import java.nio.ByteBuffer
+import java.util.zip.ZipEntry
+import java.util.zip.ZipFile
+
+@ExperimentalUnsignedTypes
+class ApkFile(apkFile: File) : Closeable {
+    companion object {
+        const val DEX_FILE = "classes.dex"
+        const val DEX_ADDITIONAL = "classes%d.dex"
+    }
+
+    constructor(path: String) : this(File(path))
+
+    private val zipFile: ZipFile = ZipFile(apkFile)
+
+    private fun readEntry(entry: ZipEntry): ByteArray =
+            zipFile.getInputStream(entry).use { it.readBytes() }
+
+    override fun close() =
+            zipFile.close()
+
+    val classTypes: Array<String> by lazy {
+        var ret = emptyArray<String>()
+        for (i in 1 until 1000) {
+            val path = if (i == 1) DEX_FILE else String.format(DEX_ADDITIONAL, i)
+            val entry = zipFile.getEntry(path) ?: break
+            val buffer = ByteBuffer.wrap(readEntry(entry))
+            ret += DexParser(buffer).parseClassTypes()
+        }
+        return@lazy ret
+    }
+}

src/main/kotlin/com/gh0u1l5/wechatmagician/spellbook/parser/DexHeader.kt

@@ -0,0 +1,55 @@
+package com.gh0u1l5.wechatmagician.spellbook.parser
+
+@ExperimentalUnsignedTypes
+class DexHeader {
+    var version: Int = 0
+
+    var checksum: UInt = 0u
+
+    var signature: ByteArray = ByteArray(kSHA1DigestLen)
+
+    var fileSize: UInt = 0u
+
+    var headerSize: UInt = 0u
+
+    var endianTag: UInt = 0u
+    
+    var linkSize: UInt = 0u
+    
+    var linkOff: UInt = 0u
+    
+    var mapOff: UInt = 0u
+    
+    var stringIdsSize: Int = 0
+    
+    var stringIdsOff: UInt = 0u
+    
+    var typeIdsSize: Int = 0
+    
+    var typeIdsOff: UInt = 0u
+    
+    var protoIdsSize: Int = 0
+    
+    var protoIdsOff: UInt = 0u
+    
+    var fieldIdsSize: Int = 0
+    
+    var fieldIdsOff: UInt = 0u
+    
+    var methodIdsSize: Int = 0
+    
+    var methodIdsOff: UInt = 0u
+    
+    var classDefsSize: Int = 0
+    
+    var classDefsOff: UInt = 0u
+    
+    var dataSize: Int = 0
+    
+    var dataOff: UInt = 0u
+
+    companion object {
+        const val kSHA1DigestLen = 20
+        const val kSHA1DigestOutputLen = kSHA1DigestLen * 2 + 1
+    }
+}