1 files changed, 164 insertions, 0 deletions
diff --git a/java/org/gnu/emacs/EmacsNoninteractive.java b/java/org/gnu/emacs/EmacsNoninteractive.java
new file mode 100644
index 00000000000..a3aefee5e0b
--- /dev/null
+++ b/java/org/gnu/emacs/EmacsNoninteractive.java
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+/* Communication module for Android terminals.  -*- c-file-style: "GNU" -*-
+
+Copyright (C) 2023 Free Software Foundation, Inc.
+
+This file is part of GNU Emacs.
+
+GNU Emacs is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or (at
+your option) any later version.
+
+GNU Emacs is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
+
+package org.gnu.emacs;
+
+import android.os.Looper;
+import android.os.Build;
+
+import android.content.Context;
+import android.content.res.AssetManager;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+
+/* Noninteractive Emacs.
+
+   This is the class that libandroid-emacs.so starts.
+   libandroid-emacs.so figures out the system classpath, then starts
+   dalvikvm with the framework jars.
+
+   At that point, dalvikvm calls main, which sets up the main looper,
+   creates an ActivityThread and attaches it to the main thread.
+
+   Then, it obtains an application context for the LoadedApk in the
+   application thread.
+
+   Finally, it obtains the necessary context specific objects and
+   initializes Emacs.  */
+
+@SuppressWarnings ("unchecked")
+public class EmacsNoninteractive
+{
+  private static String
+  getLibraryDirectory (Context context)
+  {
+    int apiLevel;
+
+    apiLevel = Build.VERSION.SDK_INT;
+
+    if (apiLevel >= Build.VERSION_CODES.GINGERBREAD)
+      return context.getApplicationInfo().nativeLibraryDir;
+    else if (apiLevel >= Build.VERSION_CODES.DONUT)
+      return context.getApplicationInfo().dataDir + "/lib";
+
+    return "/data/data/" + context.getPackageName() + "/lib";
+  }
+
+  public static void
+  main (String[] args)
+  {
+    Object activityThread, loadedApk;
+    Class activityThreadClass, loadedApkClass, contextImplClass;
+    Class compatibilityInfoClass;
+    Method method;
+    Context context;
+    AssetManager assets;
+    String filesDir, libDir, cacheDir;
+
+    Looper.prepare ();
+    context = null;
+    assets = null;
+    filesDir = libDir = cacheDir = null;
+
+    try
+      {
+	/* Get the activity thread.  */
+	activityThreadClass = Class.forName ("android.app.ActivityThread");
+
+	/* Get the systemMain method.  */
+	method = activityThreadClass.getMethod ("systemMain");
+
+	/* Create and attach the activity thread.  */
+	activityThread = method.invoke (null);
+
+	/* Now get an LoadedApk.  */
+	loadedApkClass = Class.forName ("android.app.LoadedApk");
+
+	/* Get a LoadedApk.  How to do this varies by Android version.
+	   On Android 2.3.3 and earlier, there is no
+	   ``compatibilityInfo'' argument to getPackageInfo.  */
+
+	if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.GINGERBREAD)
+	  {
+	    method
+	      = activityThreadClass.getMethod ("getPackageInfo",
+					       String.class,
+					       int.class);
+	    loadedApk = method.invoke (activityThread, "org.gnu.emacs",
+				       0);
+	  }
+	else
+	  {
+	    compatibilityInfoClass
+	      = Class.forName ("android.content.res.CompatibilityInfo");
+
+	    method
+	      = activityThreadClass.getMethod ("getPackageInfo",
+					       String.class,
+					       compatibilityInfoClass,
+					       int.class);
+	    loadedApk = method.invoke (activityThread, "org.gnu.emacs", null,
+				       0);
+	  }
+
+	if (loadedApk == null)
+	  throw new RuntimeException ("getPackageInfo returned NULL");
+
+	/* Now, get a context.  */
+	contextImplClass = Class.forName ("android.app.ContextImpl");
+	method = contextImplClass.getDeclaredMethod ("createAppContext",
+						     activityThreadClass,
+						     loadedApkClass);
+	method.setAccessible (true);
+	context = (Context) method.invoke (null, activityThread, loadedApk);
+
+	/* Don't actually start the looper or anything.  Instead, obtain
+	   an AssetManager.  */
+	assets = context.getAssets ();
+
+	/* Now configure Emacs.  The class path should already be set.  */
+
+	filesDir = context.getFilesDir ().getCanonicalPath ();
+	libDir = getLibraryDirectory (context);
+	cacheDir = context.getCacheDir ().getCanonicalPath ();
+      }
+    catch (Exception e)
+      {
+	System.err.println ("Internal error: " + e);
+	System.err.println ("This means that the Android platform changed,");
+	System.err.println ("and that Emacs needs adjustments in order to");
+	System.err.println ("obtain required system internal resources.");
+	System.err.println ("Please report this bug to bug-gnu-emacs@gnu.org.");
+
+	System.exit (1);
+      }
+
+    EmacsNative.setEmacsParams (assets, filesDir,
+				libDir, cacheDir, 0.0f,
+				0.0f, null, null);
+
+    /* Now find the dump file that Emacs should use, if it has already
+       been dumped.  */
+    EmacsApplication.findDumpFile (context);
+
+    /* Start Emacs.  */
+    EmacsNative.initEmacs (args, EmacsApplication.dumpFileName);
+  }
+};