Introduce DefaultContainer

core/src/main/java/com/topjohnwu/superuser/ContainerApp.java

@@ -18,27 +18,8 @@ package com.topjohnwu.superuser;
 
 import android.app.Application;
 
-import androidx.annotation.Nullable;
-
 /**
- * A subclass of {@link Application} with a {@link Shell.Container} injected.
+ * @deprecated
  */
-public class ContainerApp extends Application implements Shell.Container {
-
-    private volatile Shell mShell;
-
-    public ContainerApp() {
-        Shell.Config.setContainer(this);
-    }
-
-    @Nullable
-    @Override
-    public Shell getShell() {
-        return mShell;
-    }
-
-    @Override
-    public void setShell(@Nullable Shell shell) {
-        mShell = shell;
-    }
-}
+@Deprecated
+public class ContainerApp extends Application {}

core/src/main/java/com/topjohnwu/superuser/Shell.java

@@ -18,6 +18,7 @@ package com.topjohnwu.superuser;
 
 import android.content.Context;
 
+import com.topjohnwu.superuser.internal.DefaultContainer;
 import com.topjohnwu.superuser.internal.Factory;
 import com.topjohnwu.superuser.internal.InternalUtils;
 import com.topjohnwu.superuser.internal.UiThreadHandler;
@@ -42,24 +43,17 @@ import androidx.annotation.Nullable;
 /**
  * A class providing an API to an interactive (root) shell.
  * <p>
- * Sharing shells means that the {@code Shell} instance would need to be stored somewhere.
- * Generally, most developers would want to have the {@code Shell} instance shared globally
- * across the application. In that case, the developer can directly use or subclass the the readily
- * available {@link com.topjohnwu.superuser.ContainerApp} and the setup is all done. If you already
- * overridden {@link android.app.Application}, and it is impossible to change the base class,
- * or for some reason one would want to store the {@code Shell} instance somewhere else, check the
- * documentation of {@link Container} for more info. Once a global {@link Container} is registered,
- * use {@link #getShell()} or {@link #getShell(GetShellCallback)} to get/construct {@code Shell}.
- * <p>
- * However in most cases, developers do not need to deal with a {@code Shell} instance.
- * Use these high level APIs:
+ * In most cases, developers do not need to directly access a {@code Shell} instance.
+ * Use these high level APIs instead:
  * <ul>
  *     <li>{@link #sh(String...)}</li>
  *     <li>{@link #su(String...)}</li>
  *     <li>{@link #sh(InputStream)}</li>
  *     <li>{@link #su(InputStream)}</li>
  * </ul>
- * These methods uses the global shell and are more convenient to use.
+ * These methods not only uses the global shell instance but are also more convenient to use.
+ * The global shell instance is constructed on-demand and cached.
+ * To get the instance directly, call {@link #getShell()} or {@link #getShell(GetShellCallback)}.
  * <p>
  * Developers can check the example that came along with the library, it demonstrates many features
  * the library has to offer.
@@ -182,6 +176,12 @@ public abstract class Shell implements Closeable {
         }
     }
 
+    @NonNull
+    private static Container getContainer() {
+        Container container = weakContainer.get();
+        return container == null ? DefaultContainer.CONTAINER : container;
+    }
+
     /**
      * Get a {@code Shell} instance from the global container, return {@code null} if no active
      * shell is stored in the container or no container is assigned.
@@ -190,24 +190,17 @@ public abstract class Shell implements Closeable {
      */
     @Nullable
     public static Shell getCachedShell() {
-        Shell shell = null;
-        Container container = weakContainer.get();
-
-        if (container != null)
-            shell = container.getShell();
-
+        Shell shell = getContainer().getShell();
         if (shell != null && !shell.isAlive())
             shell = null;
 
         return shell;
     }
 
-    static void setCachedShell(Shell shell) {
+    private static void setCachedShell(Shell shell) {
         if (isInitGlobal) {
             // Set the global shell
-            Container container = weakContainer.get();
-            if (container != null)
-                container.setShell(shell);
+            getContainer().setShell(shell);
         }
     }
 
@@ -458,17 +451,10 @@ public abstract class Shell implements Closeable {
         private Config() {}
 
         /**
-         * Set the container to store the global {@code Shell} instance.
-         * <p>
-         * Future shell commands using static method APIs will automatically obtain a {@code Shell}
-         * from the container with {@link #getShell()} or {@link #getShell(GetShellCallback)}.
-         * <p>
-         * A {@link WeakReference} of the registered container would be saved statically
-         * so the container could be garbage collected to prevent memory leak if you decide to
-         * store {@code Shell} in places like {@link android.app.Activity}.
-         * @param container the container to store the global {@code Shell} instance.
+         * @deprecated
          */
-        public static void setContainer(@Nullable Container container) {
+        @Deprecated
+        public static void setContainer(@NonNull Container container) {
             weakContainer = new WeakReference<>(container);
         }
 

core/src/main/java/com/topjohnwu/superuser/internal/DefaultContainer.java

@@ -0,0 +1,25 @@
+package com.topjohnwu.superuser.internal;
+
+import com.topjohnwu.superuser.Shell;
+
+import androidx.annotation.Nullable;
+
+public class DefaultContainer implements Shell.Container {
+
+    public static final DefaultContainer CONTAINER = new DefaultContainer();
+
+    private volatile Shell shell;
+
+    private DefaultContainer() {}
+
+    @Nullable
+    @Override
+    public Shell getShell() {
+        return shell;
+    }
+
+    @Override
+    public void setShell(@Nullable Shell s) {
+        shell = s;
+    }
+}

example/src/main/AndroidManifest.xml

@@ -1,15 +1,16 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
     package="com.topjohnwu.libsuexample">
 
     <application
-        android:name=".ExampleApp"
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
-        android:theme="@style/AppTheme">
+        android:theme="@style/AppTheme"
+        tools:ignore="GoogleAppIndexingWarning">
         <activity android:name=".MainActivity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />

example/src/main/java/com/topjohnwu/libsuexample/ExampleApp.java

@@ -1,34 +0,0 @@
-package com.topjohnwu.libsuexample;
-
-import android.content.Context;
-import android.util.Log;
-
-import com.topjohnwu.superuser.BusyBoxInstaller;
-import com.topjohnwu.superuser.ContainerApp;
-import com.topjohnwu.superuser.Shell;
-
-import androidx.annotation.NonNull;
-
-public class ExampleApp extends ContainerApp {
-
-    public static final String TAG = "EXAMPLE";
-
-    static {
-        // Use internal busybox
-        Shell.Config.addInitializers(BusyBoxInstaller.class);
-        // Configuration
-        Shell.Config.setFlags(Shell.FLAG_REDIRECT_STDERR);
-        Shell.Config.verboseLogging(BuildConfig.DEBUG);
-        Shell.Config.addInitializers(ExampleInitializer.class);
-    }
-
-    // Demonstrate Shell.Initializer
-    private static class ExampleInitializer extends Shell.Initializer {
-
-        @Override
-        public boolean onInit(Context context, @NonNull Shell shell) {
-            Log.d(TAG, "onInit");
-            return true;
-        }
-    }
-}

example/src/main/java/com/topjohnwu/libsuexample/MainActivity.java

@@ -1,6 +1,7 @@
 package com.topjohnwu.libsuexample;
 
 import android.app.Activity;
+import android.content.Context;
 import android.os.Bundle;
 import android.text.TextUtils;
 import android.util.Log;
@@ -9,19 +10,42 @@ import android.widget.EditText;
 import android.widget.ScrollView;
 import android.widget.TextView;
 
+import com.topjohnwu.superuser.BusyBoxInstaller;
 import com.topjohnwu.superuser.CallbackList;
 import com.topjohnwu.superuser.Shell;
 
 import java.io.IOException;
 import java.util.List;
 
+import androidx.annotation.NonNull;
+
 public class MainActivity extends Activity {
 
+    public static final String TAG = "EXAMPLE";
+
     private TextView console;
     private EditText input;
     private ScrollView sv;
     private List<String> consoleList;
 
+    static {
+        // Configuration
+        Shell.Config.setFlags(Shell.FLAG_REDIRECT_STDERR);
+        Shell.Config.verboseLogging(BuildConfig.DEBUG);
+        // Use internal busybox
+        Shell.Config.addInitializers(BusyBoxInstaller.class, ExampleInitializer.class);
+    }
+
+    // Demonstrate Shell.Initializer
+    static class ExampleInitializer extends Shell.Initializer {
+
+        @Override
+        public boolean onInit(Context context, @NonNull Shell shell) {
+            Log.d(TAG, "onInit");
+            return true;
+        }
+    }
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
@@ -48,7 +72,7 @@ public class MainActivity extends Activity {
         async_cmd.setOnClickListener(v -> {
             Shell.sh(input.getText().toString())
                     .to(consoleList)
-                    .submit(out -> Log.d(ExampleApp.TAG, "async_cmd_result: " + out.getCode()));
+                    .submit(out -> Log.d(TAG, "async_cmd_result: " + out.getCode()));
             input.setText("");
         });