From 5f8159ec659e03b6a13ba733d86f66bc14cb648e Mon Sep 17 00:00:00 2001
From: Nullptr <tsng.nullptr@outlook.com>
Date: Thu, 26 Aug 2021 22:27:43 +0800
Subject: [PATCH] Fix cached origin_apk.bin not changed after app update

---
 .../appstub/LSPAppComponentFactoryStub.java   | 25 ++++++++++++++++---
 .../org/lsposed/lspatch/util/FileUtils.java   | 12 +++++++++
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/appstub/src/main/java/org/lsposed/lspatch/appstub/LSPAppComponentFactoryStub.java b/appstub/src/main/java/org/lsposed/lspatch/appstub/LSPAppComponentFactoryStub.java
index ecf6b6d..d416d00 100644
--- a/appstub/src/main/java/org/lsposed/lspatch/appstub/LSPAppComponentFactoryStub.java
+++ b/appstub/src/main/java/org/lsposed/lspatch/appstub/LSPAppComponentFactoryStub.java
@@ -13,10 +13,12 @@ import android.util.Log;
 
 import org.lsposed.lspatch.util.FileUtils;
 
+import java.io.File;
+import java.io.FileInputStream;
 import java.io.InputStream;
-import java.nio.file.FileAlreadyExistsException;
 import java.nio.file.Files;
 import java.nio.file.Paths;
+import java.util.zip.ZipFile;
 
 import dalvik.system.PathClassLoader;
 
@@ -41,10 +43,25 @@ public class LSPAppComponentFactoryStub extends AppComponentFactory {
         final String originalAppComponentFactoryClass = FileUtils.readTextFromInputStream(baseClassLoader.getResourceAsStream(ORIGINAL_APP_COMPONENT_FACTORY_ASSET_PATH));
 
         try {
-            try (InputStream inputStream = baseClassLoader.getResourceAsStream(ORIGINAL_APK_ASSET_PATH)) {
-                Files.copy(inputStream, Paths.get(cacheApkPath));
-            } catch (FileAlreadyExistsException ignored) {
+            File cacheApk = new File(cacheApkPath);
+            if (cacheApk.exists()) {
+                try (ZipFile sourceFile = new ZipFile(aInfo.sourceDir);
+                     InputStream is = new FileInputStream(cacheApk)) {
+                    var sourceCrc = sourceFile.getEntry(ORIGINAL_APK_ASSET_PATH).getCrc();
+                    var cacheCrc = FileUtils.calculateCrc(is);
+                    if (sourceCrc != cacheCrc) {
+                        Log.i(TAG, "Application updated, extract original apk again");
+                        cacheApk.delete();
+                    }
+                }
             }
+
+            if (!cacheApk.exists()) {
+                try (InputStream is = baseClassLoader.getResourceAsStream(ORIGINAL_APK_ASSET_PATH)) {
+                    Files.copy(is, Paths.get(cacheApkPath));
+                }
+            }
+
             appClassLoader = new PathClassLoader(cacheApkPath, aInfo.nativeLibraryDir, baseClassLoader.getParent());
 
             try {
diff --git a/appstub/src/main/java/org/lsposed/lspatch/util/FileUtils.java b/appstub/src/main/java/org/lsposed/lspatch/util/FileUtils.java
index b4f6234..99e43ab 100644
--- a/appstub/src/main/java/org/lsposed/lspatch/util/FileUtils.java
+++ b/appstub/src/main/java/org/lsposed/lspatch/util/FileUtils.java
@@ -1,9 +1,11 @@
 package org.lsposed.lspatch.util;
 
 import java.io.BufferedReader;
+import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.nio.charset.StandardCharsets;
+import java.util.zip.CRC32;
 
 public class FileUtils {
 
@@ -19,4 +21,14 @@ public class FileUtils {
         }
         return null;
     }
+
+    public static long calculateCrc(InputStream is) throws IOException {
+        CRC32 crcMaker = new CRC32();
+        byte[] buffer = new byte[65536];
+        int bytesRead;
+        while((bytesRead = is.read(buffer)) != -1) {
+            crcMaker.update(buffer, 0, bytesRead);
+        }
+        return crcMaker.getValue();
+    }
 }
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