Change Shell.EXECUTOR type from ExecutorService to Executor

Remove unnecessary restrictions

Author: topjohnwu

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023 John "topjohnwu" Wu
+ * Copyright 2024 John "topjohnwu" Wu
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -37,7 +37,6 @@
 import java.util.List;
 import java.util.Objects;
 import java.util.concurrent.Executor;
-import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
@@ -120,13 +119,13 @@ public abstract class Shell implements Closeable {
     @interface ConfigFlags {}
 
     /**
-     * The {@link ExecutorService} that manages all worker threads used in {@code libsu}.
+     * The {@link Executor} that manages all worker threads used in {@code libsu}.
      * <p>
-     * Note: If the developer decides to replace the default ExecutorService, keep in mind that
+     * Note: If the developer decides to replace the default Executor, keep in mind that
      * each {@code Shell} instance requires at least 3 threads to operate properly.
      */
     @NonNull
-    public static ExecutorService EXECUTOR = Executors.newCachedThreadPool();
+    public static Executor EXECUTOR = Executors.newCachedThreadPool();
 
 
     /**

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

@@ -34,7 +34,7 @@
 import java.util.UUID;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executor;
-import java.util.concurrent.Future;
+import java.util.concurrent.FutureTask;
 
 abstract class JobTask extends Shell.Job implements Shell.Task, Closeable {
 
@@ -75,10 +75,13 @@ public void run(@NonNull OutputStream stdin,
             result.err = list;
         }
 
-        try {
-            Future<Integer> outGobbler = EXECUTOR.submit(new StreamGobbler.OUT(stdout, result.out));
-            Future<Void> errGobbler = EXECUTOR.submit(new StreamGobbler.ERR(stderr, result.err));
+        FutureTask<Integer> outGobbler =
+                new FutureTask<>(new StreamGobbler.OUT(stdout, result.out));
+        FutureTask<Void> errGobbler = new FutureTask<>(new StreamGobbler.ERR(stderr, result.err));
+        EXECUTOR.execute(outGobbler);
+        EXECUTOR.execute(errGobbler);
 
+        try {
             for (ShellInputSource src : sources)
                 src.serve(stdin);
             stdin.write(END_CMD);

io/src/main/java/com/topjohnwu/superuser/internal/ShellPipeStream.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2023 John "topjohnwu" Wu
+ * Copyright 2024 John "topjohnwu" Wu
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -28,7 +28,7 @@
 import java.io.FileOutputStream;
 import java.io.InputStream;
 import java.io.OutputStream;
-import java.util.concurrent.Future;
+import java.util.concurrent.FutureTask;
 import java.util.concurrent.TimeUnit;
 
 class ShellPipeStream {
@@ -58,7 +58,8 @@ static InputStream openReadStream(SuFile file) throws FileNotFoundException {
             });
 
             // Open the fifo only after the shell request
-            Future<InputStream> stream = Shell.EXECUTOR.submit(() -> new FileInputStream(fifo));
+            FutureTask<InputStream> stream = new FutureTask<>(() -> new FileInputStream(fifo));
+            Shell.EXECUTOR.execute(stream);
             return stream.get(FIFO_TIMEOUT, TimeUnit.MILLISECONDS);
         } catch (Exception e) {
             if (e instanceof FileNotFoundException)
@@ -104,7 +105,8 @@ static OutputStream openWriteStream(SuFile file, boolean append) throws FileNotF
             });
 
             // Open the fifo only after the shell request
-            Future<OutputStream> stream = Shell.EXECUTOR.submit(() -> new FileOutputStream(fifo));
+            FutureTask<OutputStream> stream = new FutureTask<>(() -> new FileOutputStream(fifo));
+            Shell.EXECUTOR.execute(stream);
             return stream.get(FIFO_TIMEOUT, TimeUnit.MILLISECONDS);
         } catch (Exception e) {
             if (e instanceof FileNotFoundException)