Replace Context with ContextWrapper

realm/realm-library/src/main/java/io/realm/BaseRealm.java

@@ -37,6 +37,7 @@
 import io.realm.internal.Table;
 import io.realm.internal.UncheckedRow;
 import io.realm.internal.Util;
+import io.realm.internal.android.ContextWrapper;
 import io.realm.internal.async.RealmThreadPoolExecutor;
 import io.realm.log.RealmLog;
 import io.realm.internal.ObjectServerFacade;
@@ -60,8 +61,8 @@ abstract class BaseRealm implements Closeable {
     private static final String NOT_IN_TRANSACTION_MESSAGE =
             "Changing Realm data can only be done from inside a transaction.";
 
-    // Thread pool for all async operations (Query & transaction)
-    volatile static Context applicationContext;
+    // Android ContextWrapper. Must be initialized by calling `Realm.init()` before calling any other API's.
+    volatile static ContextWrapper contextWrapper;
 
     // Thread pool for all async operations (Query & transaction)
     static final RealmThreadPoolExecutor asyncTaskExecutor = RealmThreadPoolExecutor.newDefaultExecutor();

realm/realm-library/src/main/java/io/realm/Realm.java

@@ -21,7 +21,6 @@
 import android.content.Context;
 import android.os.Build;
 import android.util.JsonReader;
-import android.util.Log;
 
 import org.json.JSONArray;
 import org.json.JSONException;
@@ -57,6 +56,7 @@
 import io.realm.internal.RealmProxyMediator;
 import io.realm.internal.SharedRealm;
 import io.realm.internal.Table;
+import io.realm.internal.android.ContextWrapper;
 import io.realm.internal.async.RealmAsyncTaskImpl;
 import io.realm.log.RealmLog;
 import rx.Observable;
@@ -182,15 +182,16 @@ public Observable<Realm> asObservable() {
      * @see #getDefaultInstance()
      */
     public static synchronized void init(Context context) {
-        if (BaseRealm.applicationContext == null) {
+        if (BaseRealm.contextWrapper == null) {
             if (context == null) {
                 throw new IllegalArgumentException("Non-null context required.");
             }
             RealmCore.loadLibrary(context);
-            defaultConfiguration = new RealmConfiguration.Builder(context).build();
+            ContextWrapper wrapper = new ContextWrapper(context);
+            defaultConfiguration = new RealmConfiguration.Builder(wrapper).build();
             ObjectServerFacade.getSyncFacadeIfPossible().init(context);
-            BaseRealm.applicationContext = context.getApplicationContext();
-            SharedRealm.initialize(new File(context.getFilesDir(), ".realm.temp"));
+            BaseRealm.contextWrapper = wrapper;
+            SharedRealm.initialize(new File(wrapper.getDefaultRealmFileDirectory(), ".realm.temp"));
         }
     }
 

realm/realm-library/src/main/java/io/realm/RealmConfiguration.java

@@ -16,7 +16,6 @@
 
 package io.realm;
 
-import android.content.Context;
 import android.text.TextUtils;
 
 import java.io.File;
@@ -32,9 +31,9 @@
 import io.realm.annotations.RealmModule;
 import io.realm.exceptions.RealmException;
 import io.realm.exceptions.RealmFileException;
-import io.realm.internal.RealmCore;
 import io.realm.internal.RealmProxyMediator;
 import io.realm.internal.SharedRealm;
+import io.realm.internal.android.ContextWrapper;
 import io.realm.internal.modules.CompositeMediator;
 import io.realm.internal.modules.FilterableMediator;
 import io.realm.rx.RealmObservableFactory;
@@ -187,7 +186,8 @@ boolean hasAssetFile() {
      * @throws IOException if copying the file fails.
      */
     InputStream getAssetFile() throws IOException {
-        return BaseRealm.applicationContext.getAssets().open(assetFilePath);
+        return BaseRealm.contextWrapper.getAsset(assetFilePath);
+
     }
 
     /**
@@ -391,20 +391,19 @@ public static class Builder {
          * change depending on vendor implementations of Android.
          */
         public Builder() {
-            this(BaseRealm.applicationContext);
+            this(BaseRealm.contextWrapper);
         }
 
-        Builder(Context context) {
+        Builder(ContextWrapper context) {
             if (context == null) {
                 throw new IllegalStateException("Call `Realm.init(Context)` before creating a RealmConfiguration");
             }
-            RealmCore.loadLibrary(context);
             initializeBuilder(context);
         }
 
         // Setup builder in its initial state
-        private void initializeBuilder(Context context) {
-            this.directory = context.getFilesDir();
+        private void initializeBuilder(ContextWrapper context) {
+            this.directory = context.getDefaultRealmFileDirectory();
             this.fileName = Realm.DEFAULT_REALM_NAME;
             this.key = null;
             this.schemaVersion = 0;

realm/realm-library/src/main/java/io/realm/internal/android/ContextWrapper.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2016 Realm Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.realm.internal.android;
+
+import android.content.Context;
+import android.content.res.AssetManager;
+
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * This class wraps the Android Context class by extracting all relevant information from the context.
+ * This means we only need the Context when {@link io.realm.Realm#init(Context)} is called, but we don't
+ * need to hold onto it.
+ *
+ * This should also make Realm play nicer with Instant Run.
+ */
+public class ContextWrapper {
+
+    private final AssetManager assetManager;
+    private File filesDir;
+
+    public ContextWrapper(Context applicationContext) {
+        assetManager = applicationContext.getAssets();
+        filesDir = applicationContext.getFilesDir();
+    }
+
+    /**
+     * Returns the default location for Realm files.
+     */
+    public File getDefaultRealmFileDirectory() {
+        return filesDir;
+    }
+
+    /**
+     * Returns an asset specified by a given path.
+     * On Android this path is assumed to be a path under the {@code assets} folder.
+     */
+    public InputStream getAsset(String assetFilePath) throws IOException {
+        return assetManager.open(assetFilePath);
+    }
+}

realm/realm-library/src/objectServer/java/io/realm/SyncConfiguration.java

@@ -16,8 +16,6 @@
 
 package io.realm;
 
-import android.content.Context;
-
 import java.io.File;
 import java.io.UnsupportedEncodingException;
 import java.net.URI;
@@ -34,6 +32,7 @@
 import io.realm.exceptions.RealmException;
 import io.realm.internal.RealmProxyMediator;
 import io.realm.internal.SharedRealm;
+import io.realm.internal.android.ContextWrapper;
 import io.realm.internal.syncpolicy.AutomaticSyncPolicy;
 import io.realm.internal.syncpolicy.SyncPolicy;
 import io.realm.rx.RealmObservableFactory;
@@ -277,14 +276,14 @@ public static final class Builder  {
          * @see SyncUser#isValid()
          */
         public Builder(SyncUser user, String uri) {
-            this(BaseRealm.applicationContext, user, uri);
+            this(BaseRealm.contextWrapper, user, uri);
         }
 
-        Builder(Context context, SyncUser user, String url) {
+        Builder(ContextWrapper context, SyncUser user, String url) {
             if (context == null) {
                 throw new IllegalStateException("Call `Realm.init(Context)` before creating a SyncConfiguration");
             }
-            this.defaultFolder = new File(context.getFilesDir(), "realm-object-server");
+            this.defaultFolder = new File(context.getDefaultRealmFileDirectory(), "realm-object-server");
             if (Realm.getDefaultModule() != null) {
                 this.modules.add(Realm.getDefaultModule());
             }