Add PendingIntent in TermuxService to return data from execution

This commit adds an optional final argument to the BackgroundJob
constructor for a PendingIntent to return the results of its
execution to, and also attempts to pass an optional pendingIntent to
it from the Service start intent

app/src/main/java/com/termux/app/BackgroundJob.java

@@ -1,5 +1,9 @@
 package com.termux.app;
 
+import android.app.Activity;
+import android.app.PendingIntent;
+import android.content.Intent;
+import android.os.Bundle;
 import android.util.Log;
 
 import java.io.BufferedReader;
@@ -25,6 +29,10 @@ public final class BackgroundJob {
     final Process mProcess;
 
     public BackgroundJob(String cwd, String fileToExecute, final String[] args, final TermuxService service){
+        this(cwd, fileToExecute, args, service, null);
+    }
+
+    public BackgroundJob(String cwd, String fileToExecute, final String[] args, final TermuxService service, PendingIntent pendingIntent) {
         String[] env = buildEnvironment(false, cwd);
         if (cwd == null) cwd = TermuxService.HOME_PATH;
 
@@ -43,6 +51,28 @@ public final class BackgroundJob {
 
         mProcess = process;
         final int pid = getPid(mProcess);
+        final Bundle result = new Bundle();
+        final StringBuilder outResult = new StringBuilder();
+        final StringBuilder errResult = new StringBuilder();
+
+        Thread errThread = new Thread() {
+            @Override
+            public void run() {
+                InputStream stderr = mProcess.getErrorStream();
+                BufferedReader reader = new BufferedReader(new InputStreamReader(stderr, StandardCharsets.UTF_8));
+                String line;
+                try {
+                    // FIXME: Long lines.
+                    while ((line = reader.readLine()) != null) {
+                        errResult.append(line).append('\n');
+                        Log.i(LOG_TAG, "[" + pid + "] stderr: " + line);
+                    }
+                } catch (IOException e) {
+                    // Ignore.
+                }
+            }
+        };
+        errThread.start();
 
         new Thread() {
             @Override
@@ -50,11 +80,13 @@ public final class BackgroundJob {
                 Log.i(LOG_TAG, "[" + pid + "] starting: " + processDescription);
                 InputStream stdout = mProcess.getInputStream();
                 BufferedReader reader = new BufferedReader(new InputStreamReader(stdout, StandardCharsets.UTF_8));
+
                 String line;
                 try {
                     // FIXME: Long lines.
                     while ((line = reader.readLine()) != null) {
                         Log.i(LOG_TAG, "[" + pid + "] stdout: " + line);
+                        outResult.append(line).append('\n');
                     }
                 } catch (IOException e) {
                     Log.e(LOG_TAG, "Error reading output", e);
@@ -68,26 +100,25 @@ public final class BackgroundJob {
                     } else {
                         Log.w(LOG_TAG, "[" + pid + "] exited with code: " + exitCode);
                     }
-                } catch (InterruptedException e) {
-                    // Ignore.
-                }
-            }
-        }.start();
 
+                    result.putString("stdout", outResult.toString());
+                    result.putInt("exitCode", exitCode);
 
-        new Thread() {
-            @Override
-            public void run() {
-                InputStream stderr = mProcess.getErrorStream();
-                BufferedReader reader = new BufferedReader(new InputStreamReader(stderr, StandardCharsets.UTF_8));
-                String line;
+                    errThread.join();
+                    result.putString("stderr", errResult.toString());
+
+                    Intent data = new Intent();
+                    data.putExtra("result", result);
+
+                    if(pendingIntent != null) {
                         try {
-                    // FIXME: Long lines.
-                    while ((line = reader.readLine()) != null) {
-                        Log.i(LOG_TAG, "[" + pid + "] stderr: " + line);
+                            pendingIntent.send(service.getApplicationContext(), Activity.RESULT_OK, data);
+                        } catch (PendingIntent.CanceledException e) {
+                            // The caller doesn't want the result? That's fine, just ignore
                         }
-                } catch (IOException e) {
-                    // Ignore.
+                    }
+                } catch (InterruptedException e) {
+                    // Ignore
                 }
             }
         }.start();

app/src/main/java/com/termux/app/TermuxService.java

@@ -148,7 +148,7 @@ public final class TermuxService extends Service implements SessionChangedCallba
             String cwd = intent.getStringExtra(EXTRA_CURRENT_WORKING_DIRECTORY);
 
             if (intent.getBooleanExtra(EXTRA_EXECUTE_IN_BACKGROUND, false)) {
-                BackgroundJob task = new BackgroundJob(cwd, executablePath, arguments, this);
+                BackgroundJob task = new BackgroundJob(cwd, executablePath, arguments, this, intent.getParcelableExtra("pendingIntent"));
                 mBackgroundTasks.add(task);
                 updateNotification();
             } else {