Load libs from splits by path

Summary: [If a library is located under one of the standard paths (for example it is located directly under base.apk!/lib/arm64/ directory) then it can be loaded via path](https://cs.android.com/android/platform/superproject/main/+/main:bionic/linker/linker_namespaces.cpp;l=50). As a result we don't need to load libs by name when the app is installed on sd-card.

Reviewed By: adicatana

Differential Revision: D56573273

fbshipit-source-id: 9b8e485c9742ef1fac93f7a5695bc83792d0588d

java/com/facebook/soloader/DirectSplitSoSource.java

@@ -16,6 +16,7 @@
 
 package com.facebook.soloader;
 
+import android.annotation.SuppressLint;
 import android.os.Build;
 import android.os.StrictMode;
 import java.io.File;
@@ -25,7 +26,7 @@
 import java.util.Set;
 import javax.annotation.Nullable;
 
-public abstract class DirectSplitSoSource extends SoSource {
+public class DirectSplitSoSource extends SoSource {
   protected final String mSplitName;
 
   protected @Nullable Manifest mManifest = null;
@@ -35,19 +36,6 @@ public DirectSplitSoSource(String splitName) {
     mSplitName = splitName;
   }
 
-  public DirectSplitSoSource(String splitName, Manifest manifest) {
-    mSplitName = splitName;
-    mManifest = manifest;
-    mLibs = new HashSet<String>(manifest.libs);
-  }
-
-  public DirectSplitSoSource(
-      String splitName, @Nullable Manifest manifest, @Nullable Set<String> libs) {
-    mSplitName = splitName;
-    mManifest = manifest;
-    mLibs = libs;
-  }
-
   Manifest getManifest() {
     if (mManifest == null) {
       throw new IllegalStateException("prepare not called");
@@ -78,7 +66,16 @@ public int loadLibrary(String soName, int loadFlags, StrictMode.ThreadPolicy thr
     return LOAD_RESULT_NOT_FOUND;
   }
 
-  protected abstract int loadLibraryImpl(String soName, int loadFlags);
+  @SuppressLint("MissingSoLoaderLibrary")
+  protected int loadLibraryImpl(String soName, int loadFlags) {
+    @Nullable String path = getLibraryPath(soName);
+    if (path == null) {
+      throw new NullPointerException();
+    }
+
+    System.load(path);
+    return LOAD_RESULT_LOADED;
+  }
 
   @Override
   @Nullable
@@ -154,4 +151,9 @@ public String[] getSoSourceAbis() {
     }
     return new String[] {mManifest.arch};
   }
+
+  @Override
+  public String getName() {
+    return "DirectSplitSoSource";
+  }
 }

java/com/facebook/soloader/SoLoader.java

@@ -356,7 +356,7 @@ private static void initSoSources(Context context, int flags) throws IOException
         addSystemLoadWrapperSoSource(context, soSources);
       } else if (isEnabledBaseApkSplitSource) {
         addSystemLibSoSource(soSources);
-        soSources.add(0, new DirectSplitSoSourceLoadByName("base"));
+        soSources.add(0, new DirectSplitSoSource("base"));
       } else {
         addSystemLibSoSource(soSources);