Update Android port

* doc/emacs/android.texi (Android Startup, Android Environment):
Document that restrictions on starting Emacs have been lifted.

* java/README: Document Java for Emacs developers and how the
Android port works.

* java/org/gnu/emacs/EmacsApplication.java (EmacsApplication)
(findDumpFile): New function.
(onCreate): Factor out dump file finding functions to there.

* java/org/gnu/emacs/EmacsNative.java (EmacsNative): Update
function declarations.
* java/org/gnu/emacs/EmacsNoninteractive.java
(EmacsNoninteractive): New class.

* java/org/gnu/emacs/EmacsService.java (EmacsService, getApkFile)
(onCreate): Pass classpath to setEmacsParams.
* java/org/gnu/emacs/EmacsThread.java (EmacsThread): Make run an
override.
* lisp/loadup.el: Don't dump on Android when noninteractive.
* lisp/shell.el (shell--command-completion-data): Handle
inaccessible directories.
* src/Makefile.in (android-emacs): Link with gnulib.
* src/android-emacs.c (main): Implement to launch app-process
and then EmacsNoninteractive.
* src/android.c (setEmacsParams): New argument `class_path'.
Don't set stuff up when running noninteractive.
* src/android.h (initEmacs): Likewise.
* src/androidfont.c (init_androidfont):
* src/androidselect.c (init_androidselect): Don't initialize
when running noninteractive.
* src/emacs.c (load_pdump): New argument `dump_file'.
(android_emacs_init): Give new argument `dump_file' to
`load_pdump'.
* src/sfntfont-android.c (init_sfntfont_android): Don't
initialize when running noninteractive.

5 files changed, 243 insertions, 46 deletions

diff --git a/java/org/gnu/emacs/EmacsApplication.java b/java/org/gnu/emacs/EmacsApplication.java
index 87085c32d62..96328b99d1c 100644
--- a/java/org/gnu/emacs/EmacsApplication.java
+++ b/java/org/gnu/emacs/EmacsApplication.java
@@ -22,27 +22,20 @@ package org.gnu.emacs;
 import java.io.File;
 import java.io.FileFilter;
 
+import android.content.Context;
+
 import android.app.Application;
 import android.util.Log;
 
-public class EmacsApplication extends Application implements FileFilter
+public class EmacsApplication extends Application
 {
   private static final String TAG = "EmacsApplication";
 
   /* The name of the dump file to use.  */
   public static String dumpFileName;
 
-  @Override
-  public boolean
-  accept (File file)
-  {
-    return (!file.isDirectory ()
-            && file.getName ().endsWith (".pdmp"));
-  }
-
-  @Override
-  public void
-  onCreate ()
+  public static void
+  findDumpFile (Context context)
   {
     File filesDirectory;
     File[] allFiles;
@@ -52,13 +45,19 @@ public class EmacsApplication extends Application implements FileFilter
     wantedDumpFile = ("emacs-" + EmacsNative.getFingerprint ()
                       + ".pdmp");
 
-    Log.d (TAG, "onCreate: looking for " + wantedDumpFile);
-
     /* Obtain a list of all files ending with ``.pdmp''.  Then, look
        for a file named ``emacs-<fingerprint>.pdmp'' and delete the
        rest.  */
-    filesDirectory = getFilesDir ();
-    allFiles = filesDirectory.listFiles (this);
+    filesDirectory = context.getFilesDir ();
+    allFiles = filesDirectory.listFiles (new FileFilter () {
+        @Override
+        public boolean
+        accept (File file)
+        {
+          return (!file.isDirectory ()
+                  && file.getName ().endsWith (".pdmp"));
+        }
+      });
 
     /* Now try to find the right dump file.  */
     for (i = 0; i < allFiles.length; ++i)
@@ -69,9 +68,13 @@ public class EmacsApplication extends Application implements FileFilter
           /* Delete this outdated dump file.  */
           allFiles[i].delete ();
       }
+  }
 
-    Log.d (TAG, "onCreate: found " + dumpFileName);
-
+  @Override
+  public void
+  onCreate ()
+  {
+    findDumpFile (this);
     super.onCreate ();
   }
 };
diff --git a/java/org/gnu/emacs/EmacsNative.java b/java/org/gnu/emacs/EmacsNative.java
index 9636561a524..a772b965301 100644
--- a/java/org/gnu/emacs/EmacsNative.java
+++ b/java/org/gnu/emacs/EmacsNative.java
@@ -29,8 +29,7 @@ public class EmacsNative
      can be used to determine the dump file name.  */
   public static native String getFingerprint ();
 
-  /* Set certain parameters before initializing Emacs.  This proves
-     that libemacs.so is being loaded from Java code.
+  /* Set certain parameters before initializing Emacs.
 
      assetManager must be the asset manager associated with the
      context that is loading Emacs.  It is saved and remains for the
@@ -48,19 +47,26 @@ public class EmacsNative
      pixelDensityX and pixelDensityY are the DPI values that will be
      used by Emacs.
 
-     emacsService must be the emacsService singleton.  */
+     classPath must be the classpath of this app_process process, or
+     NULL.
+
+     emacsService must be the EmacsService singleton, or NULL.  */
   public static native void setEmacsParams (AssetManager assetManager,
                                             String filesDir,
                                             String libDir,
                                             String cacheDir,
                                             float pixelDensityX,
                                             float pixelDensityY,
+                                            String classPath,
                                             EmacsService emacsService);
 
   /* Initialize Emacs with the argument array ARGV.  Each argument
      must contain a NULL terminated string, or else the behavior is
-     undefined.  */
-  public static native void initEmacs (String argv[]);
+     undefined.
+
+     DUMPFILE is the dump file to use, or NULL if Emacs is to load
+     loadup.el itself.  */
+  public static native void initEmacs (String argv[], String dumpFile);
 
   /* Abort and generate a native core dump.  */
   public static native void emacsAbort ();
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
@@ -0,0 +1,164 @@
+/* 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);
+  }
+};
diff --git a/java/org/gnu/emacs/EmacsService.java b/java/org/gnu/emacs/EmacsService.java
index 4db1ea5359f..91db76b08e3 100644
--- a/java/org/gnu/emacs/EmacsService.java
+++ b/java/org/gnu/emacs/EmacsService.java
@@ -41,6 +41,9 @@ import android.app.Service;
 
 import android.content.Context;
 import android.content.Intent;
+import android.content.pm.ApplicationInfo;
+import android.content.pm.PackageManager.ApplicationInfoFlags;
+import android.content.pm.PackageManager;
 import android.content.res.AssetManager;
 
 import android.net.Uri;
@@ -118,8 +121,38 @@ public class EmacsService extends Service
     return null;
   }
 
+  @SuppressWarnings ("deprecation")
+  private String
+  getApkFile ()
+  {
+    PackageManager manager;
+    ApplicationInfo info;
+
+    manager = getPackageManager ();
+
+    try
+      {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.TIRAMISU)
+          info = manager.getApplicationInfo ("org.gnu.emacs", 0);
+        else
+          info = manager.getApplicationInfo ("org.gnu.emacs",
+                                             ApplicationInfoFlags.of (0));
+
+        /* Return an empty string upon failure.  */
+
+        if (info.sourceDir != null)
+          return info.sourceDir;
+
+        return "";
+      }
+    catch (Exception e)
+      {
+        return "";
+      }
+  }
+
   @TargetApi (Build.VERSION_CODES.GINGERBREAD)
-  String
+  private String
   getLibraryDirectory ()
   {
     int apiLevel;
@@ -142,7 +175,7 @@ public class EmacsService extends Service
   {
     AssetManager manager;
     Context app_context;
-    String filesDir, libDir, cacheDir;
+    String filesDir, libDir, cacheDir, classPath;
     double pixelDensityX;
     double pixelDensityY;
 
@@ -162,13 +195,18 @@ public class EmacsService extends Service
         libDir = getLibraryDirectory ();
         cacheDir = app_context.getCacheDir ().getCanonicalPath ();
 
+        /* Now provide this application's apk file, so a recursive
+           invocation of app_process (through android-emacs) can
+           find EmacsNoninteractive.  */
+        classPath = getApkFile ();
+
         Log.d (TAG, "Initializing Emacs, where filesDir = " + filesDir
-               + " and libDir = " + libDir);
+               + ", libDir = " + libDir + ", and classPath = " + classPath);
 
         EmacsNative.setEmacsParams (manager, filesDir, libDir,
                                     cacheDir, (float) pixelDensityX,
                                     (float) pixelDensityY,
-                                    this);
+                                    classPath, this);
 
         /* Start the thread that runs Emacs.  */
         thread = new EmacsThread (this, needDashQ);
@@ -491,8 +529,6 @@ public class EmacsService extends Service
   public static void
   startEmacsService (Context context)
   {
-    PendingIntent intent;
-
     if (EmacsService.SERVICE == null)
       {
         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O)
diff --git a/java/org/gnu/emacs/EmacsThread.java b/java/org/gnu/emacs/EmacsThread.java
index 5b76d11db4b..f5e9d54044a 100644
--- a/java/org/gnu/emacs/EmacsThread.java
+++ b/java/org/gnu/emacs/EmacsThread.java
@@ -33,30 +33,18 @@ public class EmacsThread extends Thread
     this.startDashQ = startDashQ;
   }
 
+  @Override
   public void
   run ()
   {
     String args[];
 
-    if (EmacsApplication.dumpFileName == null)
-      {
-        if (!startDashQ)
-          args = new String[] { "libandroid-emacs.so", };
-        else
-          args = new String[] { "libandroid-emacs.so", "-Q", };
-      }
+    if (!startDashQ)
+      args = new String[] { "libandroid-emacs.so", };
     else
-      {
-        if (!startDashQ)
-          args = new String[] { "libandroid-emacs.so", "--dump-file",
-                                EmacsApplication.dumpFileName, };
-        else
-          args = new String[] { "libandroid-emacs.so", "-Q",
-                                "--dump-file",
-                                EmacsApplication.dumpFileName, };
-      }
+      args = new String[] { "libandroid-emacs.so", "-Q", };
 
     /* Run the native code now.  */
-    EmacsNative.initEmacs (args);
+    EmacsNative.initEmacs (args, EmacsApplication.dumpFileName);
   }
 };