Reduce unnecessary IO when using compat mode

Bridge/src/main/java/com/elderdrivers/riru/xposed/config/ConfigManager.java

@@ -1,6 +1,7 @@
 package com.elderdrivers.riru.xposed.config;
 
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.Set;
 
 import de.robv.android.xposed.SELinuxHelper;
@@ -16,24 +17,32 @@ public class ConfigManager {
     private static final String USE_WHITE_LIST = INSTALLER_DATA_BASE_DIR + "conf/usewhitelist";
     private static final String DYNAMIC_MODULES = INSTALLER_DATA_BASE_DIR + "conf/dynamicmodules";
     private static final Set<String> WHITE_LIST = Collections.singleton(INSTALLER_PACKAGE_NAME);
+    private static final HashMap<String, Boolean> compatModeCache = new HashMap<>();
     private static volatile boolean IS_DYNAMIC_MODULES = false;
 
+    public static boolean isDynamicModulesMode() {
+        return IS_DYNAMIC_MODULES;
+    }
+
     public static synchronized void setDynamicModulesMode(boolean isDynamicModulesMode) {
         if (isDynamicModulesMode != IS_DYNAMIC_MODULES) {
             IS_DYNAMIC_MODULES = isDynamicModulesMode;
         }
     }
 
-    public static boolean isDynamicModulesMode() {
-        return IS_DYNAMIC_MODULES;
-    }
-
     public static boolean shouldUseWhitelist() {
         return isFileExists(USE_WHITE_LIST);
     }
 
     public static boolean shouldUseCompatMode(String packageName) {
-        return isFileExists(COMPAT_LIST_PATH + packageName);
+        Boolean result;
+        if (compatModeCache.containsKey(packageName)
+                && (result = compatModeCache.get(packageName)) != null) {
+            return result;
+        }
+        result = isFileExists(COMPAT_LIST_PATH + packageName);
+        compatModeCache.put(packageName, result);
+        return result;
     }
 
     public static boolean shouldHook(String packageName) {

Bridge/src/main/java/com/elderdrivers/riru/xposed/dexmaker/DexMakerUtils.java

@@ -10,7 +10,6 @@ import com.elderdrivers.riru.xposed.config.ConfigManager;
 import java.util.HashMap;
 import java.util.Map;
 
-import de.robv.android.xposed.SELinuxHelper;
 import external.com.android.dx.Code;
 import external.com.android.dx.Local;
 import external.com.android.dx.TypeId;
@@ -156,8 +155,8 @@ public class DexMakerUtils {
         code.loadConstant(booleanLocal, false);
         code.loadConstant(byteLocal, (byte) 0);
         code.loadConstant(charLocal, '\0');
-        code.loadConstant(doubleLocal,0.0);
+        code.loadConstant(doubleLocal, 0.0);
-        code.loadConstant(floatLocal,0.0f);
+        code.loadConstant(floatLocal, 0.0f);
         code.loadConstant(intLocal, 0);
         code.loadConstant(longLocal, 0L);
         code.loadConstant(shortLocal, (short) 0);

Bridge/src/main/java/com/elderdrivers/riru/xposed/dexmaker/DynamicBridge.java

@@ -27,6 +27,10 @@ public final class DynamicBridge {
     private static File dexDir;
     private static File dexOptDir;
 
+    /**
+     * Reset dexPathInited flag once we enter child process
+     * since it might have been set to true in zygote process
+     */
     public static void onForkPost() {
         dexPathInited.set(false);
     }
@@ -46,36 +50,48 @@ public final class DynamicBridge {
         try {
             // for Android Oreo and later use InMemoryClassLoader
             if (!shouldUseInMemoryHook()) {
-                // using file based DexClassLoader
+                setupDexCachePath();
-                if (dexPathInited.compareAndSet(false, true)) {
-                    // delete previous compiled dex to prevent potential crashing
-                    // TODO find a way to reuse them in consideration of performance
-                    try {
-                        // we always choose to use device encrypted storage data on android N and later
-                        // in case some app is installing hooks before phone is unlocked
-                        String fixedAppDataDir = getDataPathPrefix() + getPackageName(Main.appDataDir) + "/";
-                        dexDir = new File(fixedAppDataDir, "/cache/edhookers/"
-                                + getCurrentProcessName().replace(":", "_") + "/");
-                        dexOptDir = new File(dexDir, "oat");
-                        dexDir.mkdirs();
-                        DexLog.d(Main.appProcessName + " deleting dir: " + dexOptDir.getAbsolutePath());
-                        try {
-                            FileUtils.delete(dexOptDir);
-                        } catch (Throwable throwable) {
-                        }
-                    } catch (Throwable throwable) {
-                        DexLog.e("error when init dex path", throwable);
-                    }
-                }
             }
             dexMaker.start(hookMethod, additionalHookInfo,
-                    hookMethod.getDeclaringClass().getClassLoader(), dexDir == null ? null : dexDir.getAbsolutePath());
+                    hookMethod.getDeclaringClass().getClassLoader(), getDexDirPath());
             hookedInfo.put(hookMethod, dexMaker.getCallBackupMethod());
         } catch (Exception e) {
             DexLog.e("error occur when generating dex. dexDir=" + dexDir, e);
         }
     }
 
+    private static String getDexDirPath() {
+        if (dexDir == null) {
+            return null;
+        }
+        return dexDir.getAbsolutePath();
+    }
+
+    private static void setupDexCachePath() {
+        // using file based DexClassLoader
+        if (!dexPathInited.compareAndSet(false, true)) {
+            return;
+        }
+        // delete previous compiled dex to prevent potential crashing
+        // TODO find a way to reuse them in consideration of performance
+        try {
+            // we always choose to use device encrypted storage data on android N and later
+            // in case some app is installing hooks before phone is unlocked
+            String fixedAppDataDir = getDataPathPrefix() + getPackageName(Main.appDataDir) + "/";
+            dexDir = new File(fixedAppDataDir, "/cache/edhookers/"
+                    + getCurrentProcessName().replace(":", "_") + "/");
+            dexOptDir = new File(dexDir, "oat");
+            dexDir.mkdirs();
+            DexLog.d(Main.appProcessName + " deleting dir: " + dexOptDir.getAbsolutePath());
+            try {
+                FileUtils.delete(dexOptDir);
+            } catch (Throwable throwable) {
+            }
+        } catch (Throwable throwable) {
+            DexLog.e("error when init dex path", throwable);
+        }
+    }
+
     private static boolean checkMember(Member member) {
 
         if (member instanceof Method) {

Bridge/src/main/java/com/elderdrivers/riru/xposed/dexmaker/HookerDexMaker.java

@@ -30,7 +30,6 @@ import static com.elderdrivers.riru.xposed.dexmaker.DexMakerUtils.autoBoxIfNeces
 import static com.elderdrivers.riru.xposed.dexmaker.DexMakerUtils.autoUnboxIfNecessary;
 import static com.elderdrivers.riru.xposed.dexmaker.DexMakerUtils.createResultLocals;
 import static com.elderdrivers.riru.xposed.dexmaker.DexMakerUtils.getObjTypeIdIfPrimitive;
-import static com.elderdrivers.riru.xposed.dexmaker.DexMakerUtils.shouldUseInMemoryHook;
 
 public class HookerDexMaker {
 
@@ -193,14 +192,11 @@ public class HookerDexMaker {
         generateCallBackupMethod();
 
         ClassLoader loader;
-        if (shouldUseInMemoryHook()) {
+        if (TextUtils.isEmpty(mDexDirPath)) {
             // in memory dex classloader
             byte[] dexBytes = mDexMaker.generate();
             loader = new InMemoryDexClassLoader(ByteBuffer.wrap(dexBytes), mAppClassLoader);
         } else {
-            if (TextUtils.isEmpty(mDexDirPath)) {
-                throw new IllegalArgumentException("dexDirPath should not be empty!!!");
-            }
             // Create the dex file and load it.
             loader = mDexMaker.generateAndLoad(mAppClassLoader, new File(mDexDirPath));
         }

Bridge/src/main/java/com/elderdrivers/riru/xposed/util/FileUtils.java

@@ -1,6 +1,8 @@
 package com.elderdrivers.riru.xposed.util;
 
+import android.annotation.SuppressLint;
 import android.os.Build;
+import android.os.Process;
 import android.text.TextUtils;
 
 import java.io.BufferedReader;
@@ -10,6 +12,8 @@ import java.io.FileReader;
 import java.io.FileWriter;
 import java.io.IOException;
 
+import static com.elderdrivers.riru.xposed.util.ProcessUtils.PER_USER_RANGE;
+
 public class FileUtils {
 
     public static final boolean IS_USING_PROTECTED_STORAGE = Build.VERSION.SDK_INT >= Build.VERSION_CODES.N;
@@ -71,7 +75,11 @@ public class FileUtils {
         return dataDir.substring(lastIndex + 1);
     }
 
+    // FIXME: Although multi-users is considered here, but compat mode doesn't support other users' apps on Oreo and later yet.
+    @SuppressLint("SdCardPath")
     public static String getDataPathPrefix() {
-        return IS_USING_PROTECTED_STORAGE ? "/data/user_de/0/" : "/data/data/";
+        int userId = Process.myUid() / PER_USER_RANGE;
+        String format = IS_USING_PROTECTED_STORAGE ? "/data/user_de/%d/" : "/data/user/%d/";
+        return String.format(format, userId);
     }
 }

Bridge/src/main/java/com/elderdrivers/riru/xposed/util/ProcessUtils.java

@@ -12,6 +12,10 @@ import java.io.InputStreamReader;
 
 public class ProcessUtils {
 
+    // Copied from UserHandle, indicates range of uids allocated for a user.
+    public static final int PER_USER_RANGE = 100000;
+    public static final int USER_SYSTEM = 0;
+
     public static String getCurrentProcessName() {
         String prettyName = Main.appProcessName;
         if (!TextUtils.isEmpty(prettyName)) {